JP7737889B2 - Boom control devices for construction machinery - Google Patents

Description

The present invention relates to a boom control device that controls the operation of a multi-stage boom that can be extended and retracted in the longitudinal direction in a construction machine.

Patent Document 1 discloses a crane as a construction machine equipped with a multi-stage boom that can be extended and retracted in the longitudinal direction. In this crane, the multi-stage boom has a rear section attached to an upper rotating body and a front section detachably attached to the rear section. In a crane in which the front section of the multi-stage boom can be separated from the rear section, the number of sections of the multi-stage boom differs between a state in which the front section is attached to the rear section and a state in which the front section is separated from the rear section. Furthermore, in a crane in which the front section of the multi-stage boom can be separated from the rear section, the front section is transported to a work site or the like detached from the rear section. Then, at the work site, work is performed using a multi-stage boom in which the front section is attached to the rear section and the front section is attached to the rear section.

In addition, in Patent Document 1, a cord extends from a reel installed in the rear portion toward the front side. The end (distal end) of the cord extending from the reel can be selectively connected to either the front portion or the rear portion. When attaching the front portion to the rear portion, the extended end of the cord is detached from the rear portion and connected to the front portion. On the other hand, when separating the front portion from the rear portion, the extended end of the cord is detached from the front portion and connected to the rear portion.

Japanese Patent Application Laid-Open No. 2021-38072

In construction machinery with a multi-stage boom in which the front section can be separated from the rear section, as in Patent Document 1, the number of sections of the multi-stage boom varies depending on whether the front section is attached to the rear section, and therefore the weight and longitudinal length of the multi-stage boom vary depending on whether the front section is attached to the rear section. For this reason, there is a need to safely and appropriately control the extension and retraction of the multi-stage boom by appropriately controlling the extension and retraction of the telescopic cylinder that extends and retracts the multi-stage boom depending on whether the front section is attached to the rear section. There is also a need to appropriately calculate the real-time working radius of the multi-stage boom, the real-time load (actual load) applied to the multi-stage boom, and the limit value (upper limit) for the load applied to the multi-stage boom depending on whether the front section is attached to the rear section, and to safely and appropriately control the operation of the multi-stage boom based on the calculation results.

Furthermore, in a multi-section boom in which the front section can be separated from the rear section, as mentioned above, it is necessary to change the connection destination of the extended cord end when attaching the front section to the rear section and when separating the front section from the rear section. There is a need to simplify the process of changing the connection destination of the extended cord end, for example, by changing the connection destination of the extended cord end when the multi-section boom is fully retracted.

The present invention was made to solve the above-mentioned problems, and its purpose is to provide a boom control device for construction machinery that appropriately and safely controls the operation of a multi-stage boom depending on whether the detachable front section is attached to the rear section, and simplifies the task of changing the connection destination of the extended cord end.

In order to achieve the above-mentioned objective, one aspect of the present invention is a boom control device that controls the operation of a multi-stage boom, which includes a rearmost base boom member and multiple telescopic boom members that are longitudinally extendable and retractable relative to the base boom member, and a front section formed from one or more of the telescopic boom members that is detachably attached to a rear section formed from the base boom member and one or more of the telescopic boom members, and includes a cord extending from the rear section and having an extension end connectable to the front section, a telescopic cylinder that can be selectively connected to one of the telescopic boom members and that extends or retracts the connected telescopic boom member by telescoping, and a telescopic cylinder that can be extended or retracted along the longitudinal direction by telescoping and retracting the telescopic boom member. a detector that moves along a front section and detects, by proximity, a detection object attached to the first telescopic boom member, which is the telescopic boom member at the rearmost section of the front section; and a controller that, when the extended end of the cord is connected to the rear section and the telescopic cylinder is connected to the second telescopic boom member, which is the telescopic boom member at the frontmost section of the rear section, determines that the front section is attached to the rear section based on the detection of the detection object on the first telescopic boom member, and controls the operation of the multi-section boom, including extension and contraction of the multi-section boom, based on the determination result of whether the front section is attached to the rear section.

This invention provides a boom control device for construction machinery that appropriately and safely controls the operation of a multi-stage boom depending on whether the detachable front section is attached to the rear section, and simplifies the process of changing the connection destination of the extended cord end.

FIG. 1 is a schematic diagram showing a state in which a front section is attached to a rear section of a multi-stage boom according to a first embodiment, and FIG. 1b is a schematic diagram showing a state in which the front section is separated from the rear section. FIG. 2 is a schematic diagram showing the rearmost boom member in the front section (first telescopic boom member), the frontmost boom member in the rear section (second telescopic boom member), and the surrounding components of the multi-section boom according to the first embodiment, with the telescopic cylinder connected to the rearmost boom member in the front section. FIG. 3 is a schematic diagram showing the rearmost boom member in the front section (first telescopic boom member), the frontmost boom member in the rear section (second telescopic boom member), and the surrounding components in a state where a telescopic cylinder is connected to the frontmost boom member in the rear section of the multi-section boom according to the first embodiment. 4A is a schematic diagram showing the multi-section boom according to the first embodiment, in which (a) the front section is attached to the rear section and each of the boom members (telescopic boom members) is in its most retracted state, (b) the state in which the fourth boom section has been extended to its most extended state from (a), (c) the state in which the cylinder tube of the telescopic cylinder has been connected to the third boom section from (b), (d) the state in which the third boom section has been extended to a predetermined retracted state from (c), (e) the state in which the fourth boom section has been released from the third boom section and the front section has been lifted up from (d), (f) the state in which the third boom section has been retracted and the front section has been separated from the rear section from (e), and (g) the state in which the third boom section has been retracted to its most retracted state from (f). FIG. 5 is a schematic diagram showing a system provided with a boom control device that controls the operation of a multi-stage boom in the first embodiment. FIG. 6 is a flowchart that schematically illustrates an example of a process for determining the attachment state between the front portion and the rear portion by the controller in the first embodiment. FIG. 7 is a schematic diagram showing the detector (first detector) and the configuration in its vicinity in a multi-stage boom according to a first modified example, in a certain state while the boom member (second telescopic boom member) is being extended from the state in FIG. 4( f) to the state in FIG. 4( e) during the operation of attaching the front section to the rear section. FIG. 8 is a schematic diagram showing the detector (first detector) and the configuration in its vicinity in a multi-stage boom according to a first modified example, in a state in which the boom member (second telescopic boom member) is further extended from the state shown in FIG. 7 . FIG. 9 is a schematic diagram showing the detector (first detector), the rearmost boom member (first telescopic boom member) in the front section, and the configuration of their vicinity in a multi-stage boom according to a second modified example.

Embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
First, a first embodiment will be described. FIGS. 1A and 1B show the configuration of a multi-stage boom 1 according to the first embodiment. As shown in FIGS. 1A and 1B, the multi-stage boom 1 extends longitudinally. One longitudinal side of the multi-stage boom 1 is the rear side (the side indicated by arrow C1), and the opposite side is the front side (the side indicated by arrow C2). In a crane equipped with the multi-stage boom 1 shown in FIG. 1, a rotating body (not shown) is provided on a traveling vehicle (not shown), and the rear end of the multi-stage boom 1 is attached to the rotating body. The multi-stage boom 1 can be raised and lowered relative to the rotating body and can rotate together with the rotating body relative to the traveling vehicle. An attachment (not shown), such as a jib, can be attached to the front end of the multi-stage boom 1.

In this embodiment, the multi-stage boom 1 comprises a rear section 2 and a front section 3. The front section 3 is separably attached to the rear section 2. Therefore, in the multi-stage boom 1, the attachment state (connection state) between the front section 2 and the rear section 2 changes between two states: a state in which the front section 3 is attached to the rear section 2 as shown in Figure 1(a), and a state in which the front section 3 is separated from the rear section 2 as shown in Figure 1(b).

In the multi-stage boom 1 of this embodiment, the rear section 2 includes multiple (three in this embodiment) boom members B1 to B3. Here, the i in boom member Bi (i = 1, 2, 3) indicates the stage number in the multi-stage boom 1. Each boom member Bi extends along the longitudinal direction of the multi-stage boom 1. In the multi-stage boom 1, the rear end of boom member B1 in the rear section 2 is attached to the rotating body. In the multi-stage boom 1, boom member B1 serves as the base boom member for the rearmost stage, and boom member B1 in the rear section 2 serves as the initial stage (first stage). In the multi-stage boom 1, boom members B2 and B3 in the rear section 2 serve as the second and third stages, respectively. In the rear section 2, each of boom members B2 and B3 serves as a telescopic boom member that can be extended and retracted in the longitudinal direction of the multi-stage boom 1 relative to boom member B1, which is the base boom member. When either boom member B2 or B3 extends or contracts in the longitudinal direction, the dimensions of the rear section 2 along the longitudinal direction of the multi-stage boom 1 change.

Of the boom members Bi in the rear section 2, the first boom member B1 is located on the outermost side, and boom member B3 is located on the innermost side. Among the boom members Bi in the rear section, the higher the stage number, the more inwardly they are located. In the multi-stage boom 1, the rear end is formed by the first boom member (base boom member) B1. In the rear section 2, the front end is formed by the boom member B3. Among the boom members Bi in the rear section 2, the higher the stage number, the more forward the front end is located. Due to the configuration described above, in the rear section 2, boom member B1 is one stage rearward of boom member B2, and boom member B3 is one stage forward of boom member B2. In this embodiment, boom member B3 is the forwardmost boom member Bα in the rear section 2. When the front section 3 is separated from the rear section 2, boom member B3 (Bα) becomes the foremost section (final section) of the multi-section boom 1, and boom member B3 forms the front end of the multi-section boom 1. Therefore, when the front section 3 is separated from the rear section 2, the number of sections of the multi-section boom 1 is three.

In addition, in the multi-stage boom 1 of this embodiment, the front section 3 includes multiple (three in this embodiment) boom members B4 to B6. Here, the j in boom member Bj (j = 4, 5, 6) indicates the stage number in the multi-stage boom 1 in which the front section 3 is attached to the rear section 2. When the front section 3 is attached to the rear section 2, each boom member Bj extends along the longitudinal direction of the multi-stage boom 1. The front section 3 is attached to the rear section 2 by connecting the rear end of boom member B4 to boom member B3 (Bα) of the rear section 2. In the multi-stage boom 1 in which the front section 3 is attached to the rear section 2, boom members B4 to B6 are the fourth, fifth, and sixth stages, respectively. In addition, in the multi-stage boom 1 in which the front section 3 is attached to the rear section 2, each boom member Bj is a telescopic boom member that can be extended and retracted in the longitudinal direction of the multi-stage boom 1 relative to boom member B1, which is the base boom member. Therefore, in a multi-stage boom 1 in which the front section 3 is attached to the rear section 2, the dimensions of the multi-stage boom 1 along the longitudinal direction change when any of the boom members B2, B3, or Bj extends or contracts longitudinally. Additionally, in the front section 3, a boom head 5 is provided at the front end of boom member B6.

In a multi-stage boom 1 in which the front section 3 is attached to the rear section 2, the first boom section B1 is positioned outermost among the boom members Bi and Bj, and boom member B6 is positioned innermost. When the front section 3 is attached to the rear section 2, the higher the boom section number among the boom members Bi and Bj, the more inward the boom section is positioned. In a multi-stage boom 1 in which the front section 3 is attached to the rear section 2, the front end is formed by the boom head 5 of boom member B6. When the front section 3 is attached to the rear section 2, the higher the boom section number among the boom members Bi and Bj, the more forward the front end is located. Due to the above-described configuration, in a multi-stage boom 1 in which the front section 3 is attached to the rear section 2, boom member B3 is one section rearward of boom member B4, and boom member B5 is one section forward of boom member B4. Furthermore, when the front section 3 is attached to the rear section 2, boom member B6 is one stage forward of boom member B5, making it the forwardmost (final) boom member Bγ of the multi-stage boom 1 (front section 3). Therefore, when the front section 3 is attached to the rear section 2, the multi-stage boom 1 has six stages. Furthermore, of the boom members Bj of the front section 3 attached to the rear section 2, boom member B4 is the rearmost boom member Bβ.

A telescopic cylinder (boom telescopic cylinder) 10 is located inside the multi-section boom 1. The telescopic cylinder 10 includes a cylinder rod 11 and a cylinder tube 12. The cylinder rod 11 is connected to the first boom member B1, which is the base boom member, via a connecting member 15, such as a connecting pin. As the cylinder tube 12 moves along the longitudinal direction of the multi-section boom 1 relative to the cylinder rod 11, the telescopic cylinder 10 extends or retracts along the longitudinal direction of the multi-section boom 1, thereby telescoping. In addition, a connecting member 16, such as a grip pin, is attached to the end of the cylinder tube 12 facing the cylinder rod 11, i.e., the rear end of the cylinder tube 12. As the telescopic cylinder 10 extends or retracts, the connecting member 16, together with the cylinder tube 12, moves along the longitudinal direction of the multi-section boom 1 relative to the cylinder rod 11 and connecting member 15.

Furthermore, an engagement hole H that can engage with the connecting member 16 is formed at the rear end of each of the boom members B2, B3, and Bj, which are telescopic boom members. In the following description, the engagement hole formed in boom member B2 will be referred to as H2, and the engagement hole formed in boom member Bk of stage k will be referred to as Hk. When the front section 3 is attached to the rear section 2, regardless of the telescopic state of the multi-section boom 1, the engagement holes H2, H3, and Hj are positioned offset from each other in the longitudinal direction and are arranged in the following order from the rear side: H2, H3, H4, H5, and H6. When the front section 3 is attached to the rear section 2, it can selectively engage with one of the engagement holes H2, H3, and Hj. Therefore, when the front section 3 is attached to the rear section 2, the cylinder tube 12 can be selectively connected to either one of the boom members (telescopic boom members) B2, B3 of the rear section 2 or the boom member (telescopic boom member) Bj of the front section 3 via the connecting member 16. Furthermore, when the front section 3 is separated from the rear section 2, the engagement holes H2, H3 are offset from each other in the longitudinal direction, and are arranged in the order of H2, H3 from the rear side, regardless of the telescopic state of the multi-stage boom 1. When the front section 3 is separated from the rear section 2, the cylinder tube 12 can selectively engage with either one of the engagement holes H2, H3. Therefore, when the front section 3 is separated from the rear section 2, the cylinder tube 12 can be selectively connected to either one of the boom members (telescopic boom members) B2, B3 of the rear section 2 via the connecting member 16.

When the front section 3 is attached to the rear section 2, the cylinder tube 12 is connected to one of the boom members B2, B3, or Bj. By extending or retracting the telescopic cylinder 10, the boom member (B2, B3, or Bj) to which the cylinder tube 12 is connected extends or retracts in the longitudinal direction of the multi-section boom 1 relative to the boom member B1. This changes the longitudinal length (dimension) of the multi-section boom 1 when the front section 3 is attached to the rear section 2. In the state shown in Figure 1(a), the cylinder tube 12 is connected to boom member B6, and by extending or retracting the telescopic cylinder 10, boom member B6 can be extended or retracted relative to boom member B1. Figure 1(a) also shows the boom members (telescopic boom members) B2, B3, and Bj in their fully retracted state (0% extension). When extending or retracting one of the boom members B2, B3, or Bj, the cylinder tube 12 is connected to the boom member being extended or retracted (the corresponding one of B2, B3, or Bj) as described above, and the connection by the lock pin (not shown) to the boom member one stage behind the boom member being extended or retracted (the corresponding one of B2, B3, or Bj) is released.

When the front section 3 is separated from the rear section 2, the cylinder tube 12 is connected to one of the boom members B2 and B3. By extending or retracting the telescopic cylinder 10, the boom member (B2 or B3) to which the cylinder tube 12 is connected extends or retracts in the longitudinal direction of the multi-section boom 1 relative to the boom member B1. This changes the longitudinal length (dimension) of the multi-section boom 1, which is formed only from the rear section 2. In the state shown in Figure 1(b), the cylinder tube 12 is connected to the boom member B3, and by extending or retracting the telescopic cylinder 10, the boom member B3 can be extended or retracted relative to the boom member B1. Figure 1(b) also shows the boom members (telescopic boom members) B2 and B3 in their fully retracted state (0% extension). When extending or retracting one of the boom members B2, B3, the cylinder tube 12 is connected to the boom member being extended or retracted (the corresponding one of B2, B3) as described above, and the lock pin connection to the boom member one stage behind the boom member being extended or retracted (the corresponding one of B2, B3) is released.

In this embodiment, a reel 21 is installed on the boom member (base boom member) B1 of the rear section 2. In the multi-stage boom 1, a cord 22 extends from the reel 21 of the rear section 2 toward the front side. A connector 23 is provided on the cord 22 at the end extending from the reel 21, i.e., at the end distal to the reel 21. In a multi-stage boom 1 in which the front section 3 is attached to the rear section 2, the connector 23 (extended end) of the cord 22 is connectable to the boom head 5 of the boom member B6 of the front section 3. In a multi-stage boom 1 in which the front section 3 is separated from the rear section 2, the connector 23 (extended end) of the cord 22 is connectable to the boom member B3 of the rear section 2. Note that in a multi-stage boom 1 in which the front section 3 is separated from the rear section 2, the connector 23 of the cord 22 may be connectable to either the boom member B1 or B2 in the rear section 2, instead of the boom member B3. As mentioned above, in this embodiment, the extending end (distal end) of the cord 22 from the reel 21 can be selectively connected to either the front portion 3 or the rear portion 2.

Figures 2 and 3 show the rearmost boom member (first telescopic boom member) Bβ in the front section 3, the frontmost boom member (second telescopic boom member) Bα in the rear section 2, and the surrounding area. Each of Figures 2 and 3 shows a cross section parallel or approximately parallel to the longitudinal direction of the multi-section boom 1. Figure 2 also shows the state in which the cylinder tube 12 of the telescopic cylinder 10 is connected to the rearmost boom member B4 (Bβ) in the front section 3, with boom member B4 in its fully contracted state (0% extension). Figure 3 also shows the state in which the cylinder tube 12 of the telescopic cylinder 10 is connected to the frontmost boom member B3 (Bα) in the rear section 2, with boom member B4 in its fully extended state (100% extension).

As shown in Figures 2 and 3, the multi-section boom 1 of this embodiment is equipped with two detectors 17, 18. Each of the detectors 17, 18 is attached to the cylinder tube 12 of the telescopic cylinder 10. When the telescopic cylinder 10 extends or retracts during telescopic operation, each of the detectors 17, 18 moves along the longitudinal direction of the multi-section boom 1, together with the cylinder tube 12 and connecting member 16, relative to the cylinder rod 11 and connecting member 15. The detector (first detector) 17 is positioned forward of the connecting member 16, and is positioned forward of the connection position where the cylinder tube 12 of the telescopic cylinder 10 is connected to the telescopic boom member. The detector (second detector) 18 is not misaligned or is barely misaligned relative to the connecting member 16 in the longitudinal direction. For this reason, the detector 18 is positioned rearward and away from the detector 17. The longitudinal separation between detectors 17, 18, i.e., the longitudinal separation between connecting member 16 and detector 17, is the same or substantially the same as the longitudinal separation between engagement hole H3 (Hα) of boom member B3 (Bα) and engagement hole H4 (Hβ) of boom member B4 (Bβ) when boom member B4 (Bβ) is in a predetermined extension/contraction state. In the example shown in Figures 2 and 3, the longitudinal separation between detectors 17, 18 is the same or substantially the same as the longitudinal separation between engagement holes H3, H4 when boom member B4 is in its most extended state (100% extension).

Furthermore, a detection plate D is provided at the rear end of each of the telescopic boom members B2, B3, and Bj as the detection target of the detector 18. In each of the boom members B2, B3, and Bj, the detection plate D is not or barely misaligned with the engagement hole H in the longitudinal direction. In the following description, the detection plate provided on boom member B2 will be referred to as D2, and the detection plate provided on boom member Bk of stage number k will be referred to as Dk. When the front section 3 is attached to the rear section 2, the detection plates D2, D3, and Dj are positioned with a longitudinal offset from each other, regardless of the telescopic state of the multi-section boom 1, and are arranged in the following order from the rear: D2, D3, D4, D5, and D6. Furthermore, when the front section 3 is separated from the rear section 2, the detection plates D2 and D3 are positioned with a longitudinal offset from each other, regardless of the telescopic state of the multi-section boom 1, and are arranged in the following order from the rear: D2, D3, D4, D5, and D6.

Detector (second detector) 18 detects each of the detection plates D2, D3, and Dj, which are the detection targets, by proximity. While detector 18 is detecting one of detection plates D2, D3, or Dj, it does not detect any other detection plates. In other words, detector 18 does not simultaneously detect multiple detection plates. In the example shown in Figures 2 and 3, detector 18 is provided with multiple infrared sensors as proximity sensors, each of which emits infrared light. In this case, each infrared sensor in detector 18 receives infrared light reflected from a corresponding one of detection plates D2, D3, or Dj, thereby detecting the corresponding detection plate that reflected the infrared light. Also, in the example shown in Figures 2 and 3, a different infrared sensor receives the reflected infrared light for each of detection plates D2, D3, and Dj in detector 18. Therefore, it is possible to identify which of detection plates D2, D3, or Dj has been detected based on which infrared sensor in detector 18 received the infrared light. The proximity sensor provided in the detector 18 is not limited to an infrared sensor, but may also be a magnetic sensor, etc.

When the detector 18 is detecting one of the detection plates D2, D3, or Dj, which are the detection target, the telescopic cylinder 10 (cylinder tube 12) is connected to the corresponding telescopic boom member (B2, B3, or Bj) detected by the detector 18, or is located in a longitudinal position where the detection plate can be connected to the corresponding telescopic boom member (B2, B3, or Bj) detected by the detector 18 or in its vicinity. In the state shown in Figure 2, the telescopic cylinder 10 is connected to the rearmost boom member (first telescopic boom member) Bβ in the front section 3, and the detector 18 detects the detection plate Dβ (D4) attached to the boom member Bβ (B4). In the state shown in Figure 3, the telescopic cylinder 10 is connected to the frontmost boom member (second telescopic boom member) Bα in the rear section 2, and the detector 18 detects the detection plate Dα (D3) attached to the boom member Bα (B3).

The detector (first detector) 17 detects the detection plate D4 (Dα) attached to boom member B4, which is the rearmost boom member (first telescopic boom member) Bβ in the front section 3, as the detection target. The detector 17 is equipped with a proximity sensor that detects detection plate D4 by proximity. Detection plates other than detection plate D4 are not detected by the detector 17, even when the detector 17 approaches. In the example shown in Figures 2 and 3, the detector 17 is equipped with an infrared sensor as a proximity sensor, and detects detection plate D4 by receiving infrared light reflected by detection plate D4. Note that the proximity sensor attached to the detector 17 may be a proximity sensor other than an infrared sensor, such as a magnetic sensor. Furthermore, when the front section 3 is attached to the rear section 2 and the detector 18 is detecting detection plate D3 (Dα) of boom member B3 (Bα), the detector 17 detects detection plate D4 (Dβ) when boom member B4 (Bβ) is in the predetermined telescopic state described above. In the example shown in Figures 2 and 3, when the front section 3 is attached to the rear section 2 and the detector 18 detects the detection plate D3 of the boom member B3, the detector 17 detects the detection plate D4 when the boom member B4 is in the most extended state (extension rate 100%).

A lock pin R4 (Rβ) is provided at the rear end of the rearmost boom member B4 (Bβ) in the forward section 3. In boom member B4, the lock pin R4 (Rβ) is not misaligned or is barely misaligned in the longitudinal direction with respect to the engagement hole H4 (Hβ) and detection plate D4 (Dβ). Furthermore, the forwardmost boom member B3 (Bα) in the rear section is formed with multiple lock holes, including lock holes Eb3 (Ebα) and Ef3 (Efα), into which the lock pin R4 can engage. In boom member B3, lock hole Eb3 is located at the rear end, and lock hole Ef3 is located forward of lock hole Eb3. The lock pin R4 can be selectively coupled to any one of the multiple lock holes, including lock holes Eb3 and Ef3.

When boom member B4 (Bβ) is fully retracted (0% extension), lock pin R4 can engage with lock hole Eb3 of boom member B3. Furthermore, when boom member B4 is in the predetermined extension/contraction state described above, as shown in the example of Figures 2 and 3, when boom member B4 (Bβ) is fully extended (100% extension), lock pin R4 can engage with lock hole Ef3 of boom member B3. Note that when boom member B4 is extended or retracted, lock pin R4 does not engage with either lock hole Eb3 or Ef3. Furthermore, the front section 3 is separated from the rear section 2 with lock pin R4 not engaged with either lock hole Eb3 or Ef3.

Next, the process of separating the front section 3 from the rear section 2 will be described using Figures 4(a) to (g). To separate the front section 3 from the rear section 2, first, as shown in Figure 4(a), each of the boom members (telescopic boom members) B2, B3, and Bj is placed in its most contracted state (0% extension). At this time, the connector 23 (extended end) of the cord 22 is connected to boom member B6, which is the frontmost boom member Bγ in the front section 3. Then, the connecting member 16 is engaged with the engaging hole H4 (Hβ) of boom member B4 (Bβ), and the cylinder tube 12 of the telescopic cylinder 10 is connected to boom member B4, which is the rearmost boom member (first telescopic boom member) Bβ in the front section 3, via the connecting member 16. Then, with each of the telescopic boom members B2, B3, and Bj fully retracted and the cylinder tube 12 connected to boom member B4 (Bβ), the connector 23 (extended end) of the cord 22 is removed from boom member B6 of the front section 3 and connected to boom member B3 of the rear section 2. That is, the connector 23 is removed from the position indicated by the solid line in Figure 4(a) and connected to the position indicated by the dashed line in Figure 4(a).

As shown in Figure 4(b), with the cylinder tube 12 connected to the boom member B4 and the extended end of the cord 22 connected to the rear section 2, the telescopic cylinder 10 is extended, extending the boom member B4 to its maximum extension state (100% extension). At this time, the lock pin R4 (Rβ) is not engaged with any of the lock holes of the boom member B3, including the lock holes Eb3 (Ebα) and Ef3 (Efα), and the telescopic cylinder 10 is extended to extend the boom member B4. When the boom member B4 reaches its maximum extension state, the lock pin R4 engages with the lock hole Ef3, connecting the boom member B4 to the boom member B3. The connection of the cylinder tube 12 to the boom member B4 is then released. Then, as shown in Figure 4(c), after the cylinder tube 12 is retracted while it is not connected to any of the boom members B2, B3, or Bj, the connecting member 16 is engaged with the engaging hole H3 (Hα) of the boom member B3 (Bα), and the cylinder tube 12 of the telescopic cylinder 10 is connected to the boom member B3, which is the foremost boom member (second telescopic boom member) Bα in the rear section 2, via the connecting member 16.

As shown in Figure 4(d), with the cylinder tube 12 connected to boom member B3, the telescopic cylinder 10 is extended, extending boom member B3 to a predetermined telescopic state, such as a 50% extension ratio. At this time, the lock pin connection between boom member B3 and boom member B2 is released, and the telescopic cylinder 10 is extended to extend boom member B3. As a result, boom member B4, the rearmost boom member (first telescopic boom member) Bβ in the front section 3, reaches its maximum extension, while boom member B3, the frontmost boom member (second telescopic boom member) Bα in the rear section 2, reaches its predetermined telescopic state. With boom member B3 in its predetermined telescopic state, the lock pin R4 (Rβ) connecting boom member B4 to boom member B3 and the lock hole Ef3 (Efα) in which the lock pin R4 is engaged, are positioned forward of the forward end of boom member B2 and exposed. Then, as shown in Figure 4(e), when boom members B3 and B4 are in the extended and retracted state shown in Figure 4(d), the connection of boom member B4 to boom member B3 by lock pin R4 is forcibly released, and the front section 3 (boom member Bj) is lifted vertically upward using a crane separate from the crane on which the multi-stage boom 1 is mounted.

Then, as shown in Figure 4(f), with the front section 3 lifted, the telescopic cylinder 10 is retracted. Because the cylinder tube 12 is connected to the boom member B3, the boom member B3 (Bα) retracts from a predetermined telescopic state (e.g., a state with an extension rate of 50%) in response to the retraction of the telescopic cylinder 10. As the boom member B3 retracts from the predetermined telescopic state, the front section 3 is separated from the rear section 2. Note that Figure 4(f) shows the boom member B3 in a state retracted from the predetermined retracted state, e.g., a state with an extension rate of 15%. Then, as shown in Figure 4(g), the telescopic cylinder 10 is further retracted, bringing the boom member B3 to its fully retracted state (0% extension rate), completing the process of separating the front section 3 from the rear section 2.

The procedure for attaching the front section 3 to the rear section 2 is performed in the reverse order of the procedure for separating the front section 3 from the rear section 2. That is, when separating the front section 3 from the rear section 2, the state of the multi-stage boom 1 changes in the order of Figures 4(a), 4(b), ..., 4(f), and 4(g). Meanwhile, when attaching the front section 3 to the rear section 2, the state of the multi-stage boom 1 changes in the order of Figures 4(g), 4(f), ..., 4(b), and 4(a). Furthermore, when attaching the front section 3 to the rear section 2, the multi-stage boom 1 is first moved to the state shown in Figure 4(a), and then the connector 23 (extended end) of the cord 22 is removed from the boom member B3 of the rear section 2 and connected to the boom member B6 of the front section 3. That is, when each of the telescopic boom members B2, B3, and Bj is fully retracted and the cylinder tube 12 is connected to boom member B4 (Bβ), the connector 23 is removed from the position shown by the dashed line in Figure 4(a) and connected to the position shown by the solid line in Figure 4(a).

Figure 5 shows a system equipped with a boom control device 20 that controls the operation of the multi-stage boom 1, including its extension and retraction. As shown in Figure 5, the boom control device 20 includes the aforementioned cord 22 with a connector 23 attached to the distal end extending from the reel 21, as well as the aforementioned telescopic cylinder 10 and detectors 17 and 18. The boom control device 20 also includes a controller 25. The controller 25 includes a processor and a storage medium. The processor is an integrated circuit or circuitry including a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), or an FPGA (Field Programmable Gate Array). Only one processor may be provided, or multiple processors may be provided. Processing by the processor is performed according to a program stored in the processor or the storage medium. The storage medium also stores the processing program used by the processor, as well as parameters, functions, tables, and other information used in the processor's calculations.

The controller 25 acquires information indicating the extension and contraction history of each of the telescopic boom members that make up the multi-stage boom 1. For example, when the front section 3 is attached to the rear section 2, the controller 25 acquires the extension and contraction history of each of the boom members (telescopic boom members) B2, B3, and Bj, and acquires information indicating the real-time extension and contraction state (extension rate, etc.) of each of the boom members B2, B3, and Bj. Similarly, when the front section 3 is separated from the rear section 2, the controller 25 acquires the extension and contraction history of each of the boom members (telescopic boom members) B2 and B3, and acquires information indicating the real-time extension and contraction state (extension rate, etc.) of each of the boom members B2 and B3. The extension and contraction history of each of the telescopic boom members can be calculated based on the connection history of the cylinder tube 12 of the telescopic cylinder 10 to each of the telescopic boom members, the longitudinal length history of the multi-stage boom 1, and the extension and contraction history of the telescopic cylinder 10, etc. Additionally, a user interface (not shown) or the like can be used by an operator or the like to input operation commands related to the operation of the multi-stage boom 1, including the extension and contraction of the multi-stage boom 1. The controller 25 acquires the operation commands input via the user interface or the like.

The controller 25 also determines the connection destination of the connector 23 (extended end) of the cord 22. In a first example of determining the connection destination of the extended end of the cord 22, the controller 25 can communicate with the device attached to the connection destination of the connector 23, and acquires information related to the device attached to the connection destination of the connector 23 based on signals transmitted from the device via the cord 22. For example, when the connector 23 (extended end) is connected to the front section 3, the controller 25 can communicate with the device attached to the boom head 5 of the boom member B6 (Bγ), and when the connector 23 is connected to the rear section 2, the controller 25 can communicate with the device attached to the rear section 2. Examples of devices with which the controller 25 can communicate include a switch that detects over-winding of the rope suspending the hook from the boom head 5, and a sensor that detects parameters related to the multi-stage boom 1, such as the ground angle of the multi-stage boom 1.

In a first example, the controller 25 determines whether the connector 23 (extended end) of the cord 22 is connected based on information transmitted through the cord 22, including signals transmitted via the cord 22. For example, the address of the device attached to the connection destination of the connector 23 is transmitted to the controller 25 via the cord 22 via serial communication. In this case, different unique addresses are set for the device attached to the front section 3 and the device attached to the rear section 2. The controller 25 then determines whether the connection destination of the connector 23 is the front section 3 or the rear section 2, based on the device address transmitted via the cord 22.

In the first example, when the extended end of cord 22 is connected to front section 3, the transmission path of the signal from the device in cord 22 may be different from when the extended end of cord 22 is connected to rear section 2. In this case, controller 25 determines whether connector 23 is connected to front section 3 or rear section 2 based on the transmission path of the transmitted signal in cord 22. In the first example, when a signal from the device is not transmitted via cord 22, such as when the device address is not acquired, controller 25 determines that a detection failure has occurred at the connection destination of the extended end of cord 22 due to a break in cord 22, a device malfunction, or the like.

In the second example, when the aforementioned device is not attached to the rear section 2 and the connector 23 of the cord 22 is connected to the rear section 2, the controller 25 does not communicate via the cord 22. In this case, the controller 25 determines that the connector 23 of the cord 22 is connected to the rear section based on the fact that a signal is not transmitted via the cord 22, such as when the device address is not acquired. In this example, when the extended end of the cord 22 is connected to the front section 3, a signal from the device attached to the front section 3 is transmitted to the controller 25 via the cord 22. The controller 25 then determines whether the extended end of the cord 22 is connected to the front section 3 based on the acquired device address or the signal transmission path in the cord 22, etc. In the first and second examples described above, the controller 25 determines the connection (destination) of the connector 23 (extended end) of the cord 22 based on the presence or absence of a signal transmitted via the cord 22, the address of the device transmitted via the cord 22, or the transmission path of the signal transmitted through the cord 22.

In a third example of determining the connection destination of the extended end of the cord 22, a boom length measurement unit that measures the longitudinal length of the multi-stage boom 1 is composed of the controller 25 and the cord 22. In this case, the controller 25 acquires the measurement result of the extended length of the cord 22 from the reel 21 (rear section 2) to the extended end. The controller 25 and other components calculate the longitudinal length of the multi-stage boom 1 based on the measurement result of the extended length of the cord 22. Note that when the extended end of the cord 22 (connector 23) is connected to the front section 3, the extended length of the cord 22 from the reel 21 to the extended end is different from when the extended end of the cord 22 is connected to the rear section 2, even if the aforementioned extension history of each telescopic boom member (the extension and contraction state of each telescopic boom member) is the same. In other words, the extended length of the cord 22 changes depending on the connection destination of the extended end of the cord 22.

In the third example, the controller 25 determines the connection of the extended end of the cord 22 based on the measurement results of the aforementioned extended length of the cord 22 and the history of extension and contraction of the boom members (telescopic boom members) B2, B3 of the rear section 2 and the boom member (telescopic boom member) Bj of the front section 3 attached to the rear section 2. In other words, the connection destination of the extended end of the cord 22 is determined based on the extended length of the cord 22 and the history of extension and contraction (e.g., history of extension rates) of the second-stage and forward-stage boom members B2, B3, Bj.

For example, suppose the controller 25 acquires information indicating that the extension rate of the third stage is 50% and the extension rates of stages other than the third stage are 0% as the extension history of each boom member (telescopic boom member). In this case, if the measured value of the extension length of the cord 22 is the same as or approximately the same as value L1, the controller 25 determines that the connection destination of the extension end of the cord 22 is the rear section 2 (boom member B3). Note that in states such as those shown in Figures 4(d) and 4(e), the extension length of the cord 22 is the same as or approximately the same as value L1. If the extension length of the cord 22 is the same as or approximately the same as value L2, which is greater than value L1, the controller 25 determines that the connection destination of the extension end of the cord 22 is the front section 3 (boom member B6). Furthermore, in the third example, even if the controller 25 acquires information different from the aforementioned information as the extension and contraction history of each boom member (telescopic boom member), the controller 25 similarly determines the connection (connection destination) of the extended end of the cord 22 based on the measurement results of the extended length of the cord 22.

The controller 25 may make both a determination regarding the connection (destination) of the extended end of the cord 22 based on information transmitted from the device via the cord 22 (e.g., the first and second examples), and a determination based on the extended length of the cord (e.g., the third example). In this case, a priority order is set for the two determinations. If the two determinations yield different results, the controller 25 uses the determination result with the higher priority order as the determination result regarding the connection (destination) of the extended end of the cord 22. By making two determinations, even if a detection error occurs regarding the destination of the extended end of the cord 22 in one of the two determinations, the destination of the extended end of the cord 22 can be appropriately determined by the other of the two determinations.

The controller 25 acquires the detection results of detection plates D2, D3, and Dj, which are the detection targets of detector 18, and also acquires the detection results of detection plate D4 (Dβ), which is the detection target of detector 17. Based on the detection results of detector 18, etc., the controller 25 also determines the connection between each of the boom members (telescopic boom members) B2, B3, and Bj and the cylinder tube 12 of the telescopic cylinder 10. When determining the connection between each of the boom members B2, B3, and Bj and the cylinder tube 12, it determines whether the cylinder tube 12 is connected to any of the boom members B2, B3, and Bj, and, if the cylinder tube 12 is connected to any of the boom members B2, B3, and Bj, it determines to which of the boom members B2, B3, and Bj the cylinder tube 12 is connected.

The connection between each of the boom members B2, B3, and Bj and the cylinder tube 12 is determined using one or more of the following: the detection results from the detector 18, the operation history of the connecting member 16, the extension/retraction history of the telescopic cylinder 10, and the longitudinal length history of the multi-section boom 1. In one example, the controller 25 determines that the telescopic cylinder 10 is connected to the boom member (telescopic boom member) Bk based on the fact that the detector 18 continuously detects the detection plate Dk of the boom member Bk with stage number k over time while the telescopic cylinder 10 is being extended or retracted. In another example, the controller 25 determines that the telescopic cylinder 10 is connected to the boom member (telescopic boom member) Bk based on the fact that the detector 18 detects the detection plate Dk of the boom member Bk with stage number k and the connecting member 16 is actuated to engage with the engagement hole Hk of the boom member Bk.

The controller 25 determines the attachment state (connection state) between the front section 3 and the rear section 2 based on the results of the connection (connection destination) of the extended end (connector 23) of the cord 22, the results of the connection of the cylinder tube 12 of the telescopic cylinder 10 to each of the boom members (telescopic boom members) B2, B3, Bj, and the detection results of the detection plate Dβ (D4) in the detector (first detector) 17. At this time, it determines whether the front section 3 is attached to the rear section 2, and determines whether the front section 3 is attached to the rear section 2 as shown in Figure 1(a) or separated from the rear section 2 as shown in Figure 1(b).

Figure 6 shows an example of the process performed by the controller 25 to determine the attachment status between the front section 3 and the rear section 2. The determination process in Figure 6 is repeatedly performed over time while the controller 25 is controlling the operation of the multi-section boom 1. When the determination process in Figure 6 begins, the controller 25 determines whether the connector 23 (extended end) of the cord 22 is connected to the front section 3 (S101). The connection destination of the connector 23 is determined in the same manner as in any of the above-mentioned examples, including the first to third examples. If the connector 23 is connected to the front section 3 (S101-Yes), the controller 25 determines that the front section 3 is attached to the rear section (S102). In this case, it is determined that boom member B6 (Bγ) is the most forward section of the multi-section boom 1, and the multi-section boom 1 is determined to have six sections. If the connector 23 is not connected to the front section 3 (S101-No), the controller 25 determines whether the connector 23 (extended end) of the cord 22 is connected to the rear section 2 (S103).

If the connector 23 is connected to the rear section 2 (S103—Yes), the controller 25 determines whether the cylinder tube 12 of the telescopic cylinder 10 is connected to any of the telescopic boom members (boom members B2, B3, Bj) (S104). If the cylinder tube 12 is not connected to any of the telescopic boom members (S104—No), the controller 25 ends the process without determining the attachment status between the front section 3 and the rear section 2. In this case, the previous determination result regarding the attachment status between the front section 3 and the rear section 2 is maintained. On the other hand, if the cylinder tube 12 is connected to any of the telescopic boom members (S104—Yes), the controller 25 determines whether the cylinder tube 12 is connected to any of the boom members B4 to B6 of the front section 3 (S105). If the cylinder tube 12 is connected to one of the boom members B4 to B6 (S105-Yes), the controller 25 determines that the front section 3 is attached to the rear section 2 (S106). However, in this case, although the front section 3 is formed from boom members B4 to B6, the controller 25 determines that boom member B4 (Bβ) is the frontmost section of the multi-section boom 1 (S107). Therefore, the multi-section boom 1 is determined to have four sections.

If the cylinder tube 12 is connected to a boom member other than boom members B4 to B6 (S105—No), the controller 25 determines whether the cylinder tube 12 is connected to the boom member B3 (Bα), the forwardmost stage in the rear section 2 (S108). If the cylinder tube 12 is connected to boom member B3 (Bα) (S108—Yes), the controller 25 determines whether the detector (first detector) 17 detects detection plate D4 (Dβ) (S109). If the detector 17 detects detection plate D4 (S109—Yes), the controller 25 determines that the front section 3 is attached to the rear section 2 (S106) and that boom member B4 (Bβ) is the forwardmost stage of the multi-section boom 1 (S107). On the other hand, if the detector 17 does not detect the detection plate D4 (S109-No), the controller 25 determines that the front section 3 is separated from the rear section 2 (S110). In this case, the boom member B3 (Bα) is determined to be the frontmost section of the multi-section boom 1, and the multi-section boom 1 is determined to have three sections.

Furthermore, if the connection destination of the cylinder tube 12 is not boom member B3 (Bα) in S108 (S108-No), the controller 25 determines that the connection destination of the cylinder tube 12 is boom member B2. That is, it determines that the boom member is connected to a telescopic boom member that is rearward of boom member B3 (Bα) in the rear section 2. The controller 25 then determines that the front section 3 is separated from the rear section 2 (S110). Furthermore, if the connector 23 is not connected to the rear section 2 in S103 (S103-No), the controller 25 determines that a detection failure has occurred with respect to the connection destination of the connector 23 of the cord 22 (S111).

In one example, if the connector 23 is not connected to the front section 3 in S101 (S101-No), the controller 25 skips S103 and performs S104. In this case, if the connector 23 is not connected to the front section 3 in S101 (S101-No), the controller 25 determines that the connector 23 is connected to the rear section 2. In another example, if the connection destination of the cylinder tube 12 is other than boom members B4 to B6 in S105 (S105-No), the controller 25 skips S108 and performs S109. In this case, if the connection destination of the cylinder tube 12 is other than boom members B4 to B6 in S105 (S105-No), the controller 25 determines that the connection destination of the cylinder tube 12 is boom member B3 (Bα).

The controller 25 controls the operation of the multi-stage boom 1, including its extension and contraction, based on the determination of whether the front section 3 is attached to the rear section 2. The controller 25 also controls the operation of the multi-stage boom 1 based on the determination of which of the boom members (telescopic boom members) B2, B3, and Bj is the forwardmost section of the multi-stage boom 1, i.e., the determination of the number of sections in the multi-stage boom 1. The weight and longitudinal length of the multi-stage boom 1 vary depending on the attachment state (connection state) of the front section 3 to the rear section 2 and the number of sections in the multi-stage boom 1. Therefore, the controller 25 controls the operation of the multi-stage boom 1, including its extension and contraction, based on the real-time attachment state of the front section 3 to the rear section 2. The operation of the multi-stage boom 1 is controlled based on the results of determining the attachment status of the front section 3 to the rear section 2, the results of determining the number of sections of the multi-stage boom 1, as well as information indicating the history of extension and retraction of each telescopic boom member and operational commands related to the operation of the multi-stage boom 1.

As shown in Figure 5 and other figures, the controller 25 controls the extension and retraction of the telescopic cylinder 10, i.e., the operation of the telescopic cylinder 10, thereby controlling the extension and retraction of the multi-section boom 1. In controlling the operation of the telescopic cylinder 10, i.e., the extension and retraction of the multi-section boom 1, the controller 25 sets the extension and retraction range of the telescopic cylinder 10 in response to the determination results of the attachment state of the front section 3 to the rear section 2 and the determination results of the number of sections of the multi-section boom 1. The controller 25 then controls the operation of the telescopic cylinder 10 so that the telescopic cylinder 10 only extends and retracts within the set extension and retraction range. The set extension and retraction range of the telescopic cylinder 10 differs depending on the determination results of the attachment state of the front section 3 to the rear section 2 and the determination results of the number of sections of the multi-section boom 1. In other words, if it is determined that the front section 3 is attached to the rear section 2, the set extension and retraction range of the telescopic cylinder 10 will be different from if it is determined that the front section 3 is separated from the rear section 2. If the multi-stage boom 1 is determined to have four stages, the extension and retraction range of the telescopic cylinder 10 that is set will be different from if the multi-stage boom 1 is determined to have six stages.

When the front section 3 is attached to the rear section 2 and it is determined that boom member B6 (Bγ) is the frontmost section of the multi-section boom 1 (the multi-section boom 1 has six sections), and the cylinder tube 12 (connecting member 16) is not connected to any of the boom members B2, B3, or Bj, the telescopic range of the telescopic cylinder 10, i.e., the range within which the connecting member 16 can move in the longitudinal direction of the multi-section boom 1, is set to the range between the position where the cylinder tube 12 can be connected to boom member B2 and the position where the cylinder tube 12 can be connected to boom member B6. For example, when the boom members (telescopic boom members) B2, B3, and Bj are fully retracted (extension rate 0%) as shown in Figure 1(a), the telescopic range of the telescopic cylinder 10 when the cylinder tube 12 is not connected to any of the boom members B2, B3, or Bj is set to range δa.

Furthermore, when the front section 3 is attached to the rear section 2 and boom member B4 (Bβ) is determined to be the frontmost section of the multi-section boom 1, and the cylinder tube 12 (connecting member 16) is not connected to any of the boom members B2, B3, or Bj, the telescopic range of the telescopic cylinder 10 (the range within which the connecting member 16 can move in the longitudinal direction of the multi-section boom 1) is set to the range between the position where the cylinder tube 12 can be connected to boom member B2 and the position where the cylinder tube 12 can be connected to boom member B4. For example, when the boom members (telescopic boom members) B2, B3, and Bj are all fully retracted as shown in Figure 1(a), the telescopic range of the telescopic cylinder 10 when the cylinder tube 12 is not connected to any of the boom members B2, B3, or Bj is set to range δb.

If it is determined that the front section 3 will separate from the rear section 2, and the cylinder tube 12 (connecting member 16) is not connected to either boom member B2 or B3, the telescopic range of the telescopic cylinder 10 is set to the range between the position where the cylinder tube 12 can be connected to boom member B2 and the position where the cylinder tube 12 can be connected to boom member B3. For example, as shown in Figure 1(b), when the boom members (telescopic boom members) B2 and B3 are fully retracted, the range δc is set as the telescopic range of the telescopic cylinder 10 when the cylinder tube 12 is not connected to either boom member B2 or B3.

As shown in FIG. 5 and other figures, the controller 25, which controls the operation of the multi-stage boom 1, controls the operation of the boom hoisting cylinder (derrick cylinder) to control the hoisting of the multi-stage boom 1. In controlling the operation of the multi-stage boom 1, including its extension, contraction, and hoisting, the controller 25 calculates the real-time working radius of the multi-stage boom 1 and controls the extension, contraction, and hoisting of the multi-stage boom 1 so that the multi-stage boom 1 does not interfere with obstacles around the crane. The controller 25 also calculates the load (actual load) being applied to the multi-stage boom 1 in real time due to a lifted load, etc., and calculates and sets a limit value (upper limit value) for the load being applied to the multi-stage boom 1. The controller 25 then issues a warning when the difference between the real-time load and the limit value falls below a threshold, and forcibly stops the operation of the multi-stage boom 1, including its extension, contraction, and hoisting, if the real-time load exceeds the limit value.

Here, the real-time working radius of the multi-stage boom 1 is calculated based on the longitudinal length of the multi-stage boom 1, etc., and the real-time load (actual load) applied to the multi-stage boom 1 and the limit value of the load applied to the multi-stage boom 1 are calculated based on the longitudinal length of the multi-stage boom 1 and the weight of the multi-stage boom 1, etc. Therefore, the calculated real-time working radius and load (actual load) of the multi-stage boom 1 and the set limit value for the load of the multi-stage boom 1 differ depending on the determination result of the attachment state of the front section 3 to the rear section 2 and the determination result of the number of sections of the multi-stage boom 1. In other words, when it is determined that the front section 3 is attached to the rear section 2, the calculation results of the real-time working radius and load of the multi-stage boom 1 and the set limit value for the load of the multi-stage boom 1 will differ from when it is determined that the front section 3 is separated from the rear section 2. Furthermore, when it is determined that the multi-stage boom 1 has four stages, the calculation results for the real-time working radius and load of the multi-stage boom 1, as well as the limit value set for the load of the multi-stage boom 1, will differ from when it is determined that the multi-stage boom 1 has six stages.

In this embodiment, the process shown in FIG. 6 is performed to determine the attachment state of the front section 3 to the rear section 2. Therefore, when separating the front section 3 from the rear section 2, the controller 25 performs the following determination and process. That is, in the state shown in FIG. 4(a), when the connector 23 (extended end) of the cord 22 is connected to the front section 3 (the connector 23 is connected to the position shown by the solid line), the controller 25 determines S101 as Yes. Then, in S102, the controller 25 determines that the front section 3 is attached to the rear section 2 and determines that boom member B6 (Bγ) is the foremost section of the multi-section boom 1.

When the connection destination of the connector 23 (extended end) of the cord 22 is changed to the rear section 2 (position indicated by the dashed line) in the state shown in Figure 4(a), the controller 25 sequentially determines S101 - No, S103 - Yes, S104 - Yes, and S105 - Yes. Then, in S106, the controller 25 determines that the front section 3 is attached to the rear section 2, and in S107, the controller 25 determines that boom member B4 (Bβ) is the forwardmost section of the multi-section boom 1. After the boom member B4 is extended to the state shown in Figure 4(b), the controller 25 sequentially determines S101 - No, S103 - Yes, S104 - Yes, and S105 - Yes until the connection of the cylinder tube 12 to the boom member B4 is released, and determines the attachment state of the front section 3 to the rear section 2 as shown in S106 and S107.

When the cylinder tube 12 is released from the boom member B4 (Bβ), the controller 25 sequentially determines S101 - No, S103 - Yes, and S104 - No until the cylinder tube 12 is connected to the boom member B3 (Bα) in the state shown in Figure 4(c). Therefore, the controller 25 does not determine the attachment state between the front section 3 and the rear section 2. Therefore, until the cylinder tube 12 is connected to the boom member B3 (Bα) in the state shown in Figure 4(c), the determination that the front section 3 is attached to the rear section 2 and that the boom member B4 (Bβ) is the foremost section of the multi-section boom 1 is maintained.

When the cylinder tube 12 is connected to the boom member B3 (Bα) in the state shown in Figure 4(c), the controller 25 makes a determination in the following order: S101 - No, S103 - Yes, S104 - Yes, S105 - No, S108 - Yes. In the state shown in Figure 4(c), the detector (first detector) 17 detects the detection plate D4 (Dβ), so the controller 25 makes a determination in S109 - Yes. The controller 25 then determines in S106 that the front section 3 is attached to the rear section 2, and determines in S107 that the boom member B4 (Bβ) is the frontmost section of the multi-section boom 1. The state of the multi-stage boom 1 is then changed in the order of Figure 4(d) and Figure 4(e), and until the front section 3 is separated from the rear section 2 as shown in Figure 4(f), the controller 25 makes judgments in the order of S101 - No, S103 - Yes, S104 - Yes, S105 - No, S108 - Yes, S109 - Yes, and determines the attachment state of the front section 3 to the rear section 2 as shown in S106 and S107.

When the front section 3 is separated from the rear section 2 in the state shown in Figure 4(f), the detector 17 no longer detects detection plate D4 (Dβ). Therefore, the controller 25 determines in the following order: S101 - No, S103 - Yes, S104 - Yes, S105 - No, S108 - Yes, S109 - No. Then, in S110, the controller 25 determines that the front section 3 is separated from the rear section 2, and determines that boom member B3 (Bα) is the frontmost section of the multi-section boom 1. Then, while the boom member B3 is being retracted to the state shown in Figure 4(g), and even while it is in the state shown in Figure 4(g), the controller 25 makes determinations in the following order: S101 - No, S103 - Yes, S104 - Yes, S105 - No, S108 - Yes, S109 - No, and determines the attachment state of the front section 3 to the rear section 2 as shown in S110.

When attaching the front portion 3 to the rear portion 2, the controller 25 determines the attachment state of the front portion 3 to the rear portion 2 in each of the states shown in Figures 4(a) to 4(g) in the same manner as when separating the front portion 3 from the rear portion 2. Therefore, from the state shown in Figure 4(g) to the state shown in Figure 4(e) where the front portion 3 is attached to the rear portion 2, the controller 25 makes determinations in the order S101 - No, S103 - Yes, S104 - Yes, S105 - No, S108 - Yes, S109 - No, and determines the attachment state of the front portion 3 to the rear portion 2 as shown in S110. From the time the front section 3 is attached to the rear section until the connection of the cylinder tube 12 to the boom member B3 (Bα) in Figure 4(c) is released, the controller 25 makes determinations in the following order: S101 - No, S103 - Yes, S104 - Yes, S105 - No, S108 - Yes, S109 - Yes, and determines the attachment status of the front section 3 to the rear section 2 as shown in S106 and S107.

After the cylinder tube 12 is released from the boom member B3 (Bα), while the telescopic cylinder 10 is extended to the state shown in Figure 4(b), the controller 25 makes the following determinations in order: S101 - No, S103 - Yes, S104 - No. Therefore, the determination that the front section 3 is attached to the rear section 2 and that the boom member B4 (Bβ) is the frontmost section of the multi-section boom 1 is maintained. When the cylinder tube 12 is connected to the boom member B4 (Bβ) in the state shown in Figure 4(b), the controller 25 makes the following determinations in order: S101 - No, S103 - Yes, S104 - Yes, S105 - Yes, and makes the following determinations regarding the attachment status of the front section 3 to the rear section 2, as shown in S106 and S107. Then, in the state shown in Figure 4(a), if the connection destination of the connector 23 (extended end) of the cord 22 is changed to the front section 3 (position shown by the solid line), the controller 25 determines S101 as Yes and determines the attachment state of the front section 3 to the rear section 2 as shown in S102.

In this embodiment, when the extended end of the cord 22 is connected to the rear section 2 and the telescopic cylinder 10 is connected to the forward-most boom section Bα (B3) in the rear section 2, the controller 25 determines that the front section 3 is attached to the rear section 2 based on the detector 17 detecting the detection plate (detection object) Dβ of the rearmost boom section Bβ (B4) in the front section 3. Therefore, even if the connection destination of the extended end of the cord 22 is changed when the multi-section boom 1 is fully retracted, such as in the state shown in Figure 4(a), it is possible to appropriately determine whether the front section 3 is attached to the rear section 2 when attaching and detaching the front section 3 to and from the rear section 2.

In this embodiment, when the extended end of the cord 22 is connected to the rear section 2 and the telescopic cylinder 10 is connected to the boom member Bα (B3), the controller 25 determines that the front section 3 is separated from the rear section 2 based on the fact that the detector 17 does not detect the detection plate Dβ of the boom member Bβ (B4). Then, when the extended end of the cord 22 is connected to the rear section 2, the controller 25 determines that the front section 3 is attached to the rear section 2 based on the fact that the telescopic cylinder 10 is connected to one of the telescopic boom members B4 to B6 of the front section 3, including the boom member Bβ (B4). Furthermore, when the extended end of the cord 22 is connected to the front section 3, the controller 25 determines that the front section 3 is attached to the rear section 2 based on the fact that the extended end of the cord 22 is connected to the front section 3. This makes it possible to more appropriately determine whether the front section 3 is attached to the rear section 2 during the attachment and detachment of the front section 3 from the rear section 2, even if the connection destination of the extended end of the cord 22 is changed when the multi-stage boom 1 is fully retracted.

In this embodiment, the controller 25 controls the operation of the multi-stage boom 1, including the extension and contraction of the multi-stage boom 1, based on the determination result regarding the attachment state of the front section 3 to the rear section 2. In this embodiment, the attachment state of the front section 3 to the rear section 2 is appropriately determined, as described above. Therefore, by controlling the operation of the multi-stage boom 1 based on the appropriately determined determination result, the operation of the multi-stage boom 1 is appropriately and safely controlled depending on whether or not the front section 3 is attached to the rear section 2.

Furthermore, in this embodiment, if it is determined that the front section 3 is attached to the rear section when the extended end of the cord 22 is connected to the rear section 2, the controller 25 determines that the rearmost boom member Bβ (B4) in the front section 3 is the frontmost section of the multi-stage boom 1, and controls the operation of the multi-stage boom 1. In other words, the controller 25 determines that the multi-stage boom 1 is in the β stage (four stages in this embodiment), and controls the operation of the multi-stage boom 1. As a result, even if it is impossible to determine the number of telescopic boom members in the front section 3, i.e., even if it is impossible to determine the number of stages in the multi-stage boom 1 when the front section 3 is attached to the rear section 2, the operation of the multi-stage boom 1 can be controlled appropriately and safely.

For example, the controller 25 sets the telescopic range of the telescopic cylinder 10 based on the results of determining the attachment state of the front section 3 to the rear section 2 and the number of sections of the multi-section boom 1. This appropriately sets the telescopic range of the telescopic cylinder 10 to a range that corresponds to the real-time attachment state of the front section 3 to the rear section 2 and the number of sections of the multi-section boom 1. Therefore, by controlling the operation of the telescopic cylinder 10 so that it extends and retracts within the set telescopic range, the operation of the telescopic cylinder 10 is appropriately controlled, and the extension and retraction of the multi-section boom 1 is appropriately controlled. By appropriately controlling the operation of the telescopic cylinder 10 and the extension and retraction of the multi-section boom 1, the telescopic cylinder 10 is effectively prevented from excessively extending beyond the appropriate telescopic range. This effectively prevents the cylinder tube 12 from coming out of the cylinder guide or the front end of the cylinder tube 12 from interfering with the boom head 5.

The controller 25 also acquires the longitudinal length of the multi-stage boom 1 and the weight of the multi-stage boom 1 based on the results of the determination of the attachment state of the front section 3 to the rear section 2 and the results of the determination of the number of stages of the multi-stage boom 1, and calculates the real-time working radius of the multi-stage boom 1, the real-time load (actual load) applied to the multi-stage boom 1, and the limit value (upper limit value) for the load applied to the multi-stage boom 1. Therefore, values corresponding to the determination of the real-time attachment state of the front section 3 to the rear section 2 and the number of stages of the multi-stage boom 1 are appropriately calculated as the working radius of the multi-stage boom 1, the load (actual load) of the multi-stage boom 1, and the limit value for the load of the multi-stage boom 1. Therefore, by controlling the extension and retraction, elevation, etc. of the multi-stage boom 1 based on the calculated working radius of the multi-stage boom 1, interference of the multi-stage boom 1 with obstacles around the crane is effectively prevented. Furthermore, by controlling the operation of the multi-stage boom 1 based on the calculated load of the multi-stage boom 1 and the limit value for the load of the multi-stage boom 1, an appropriate warning is issued in response to the real-time attachment status of the front section 3 to the rear section 2, and the operation of the multi-stage boom 1 is appropriately forcibly stopped. This effectively prevents the crane from assuming a position that makes it more likely to tip over.

In addition, in this embodiment, during the attachment of the front section 3 to the rear section 2 and the detachment of the front section 3 from the rear section 2, the connection destination of the extended end of the cord 22 can be changed when the multi-stage boom 1 is fully retracted. This simplifies the process of changing the connection destination of the extended end of the cord 22. Furthermore, since the connection destination of the extended end of the cord 22 can be changed when the multi-stage boom 1 is fully retracted, work efficiency and safety are improved when changing the connection destination of the extended end of the cord 22.

(Modification)
In the first modified example, in the operation of attaching the front section 3 to the rear section 2, the controller 25 determines whether the lock pin Rβ (R4) of the boom member Bβ (B4) can engage with the lock hole Efα (Ef3) of the boom member Bα (B3). To attach the front section 3 to the rear section 2, as shown in FIG. 4(f), the front section 3 (boom member Bj) is lifted vertically upward by a crane separate from the crane on which the multi-stage boom 1 is mounted, and then the boom member Bα (B3) is extended. Then, as shown in FIG. 4(e), the boom member Bα (B3) is extended until the lock pin Rβ (R4) can engage with the lock hole Efα (Ef3). FIGS. 7 and 8 show the change in the position of the detector (first detector) 17 while the boom member (second telescopic boom member) Bα is extended from the state shown in FIG. 4(f) to the state shown in FIG. 4(e). As the boom member Bα is extended from the state shown in Figure 4(f) to the state shown in Figure 4(e), the detector 17 moves forward to the position shown in Figure 7. When the boom member Bα is further extended from the state shown in Figure 7, the detector 17 moves further forward to the position shown in Figure 8.

When the detector 17 moves forward to the position shown in Figure 8, the detector 17 begins detecting the detection plate Dβ (D4). Therefore, the point at which the detector 17 moves to the position shown in Figure 8 is the point at which the detector 17 begins detecting the detection plate Dβ. However, in the state shown in Figure 8, the lock pin Rβ (R4) of the boom member Bβ (B4) cannot engage with the lock hole Efα (Ef3) of the boom member Bα (B3). By further extending the telescopic cylinder 10 from the state shown in Figure 8 and moving the detector 17 forward to the position shown in Figure 3, the lock pin Rβ (R4) can engage with the lock hole Efα (Ef3). In this modified example, the controller 25 obtains the length of the telescopic cylinder 10 at the point at which the detector 17 begins detecting the detection plate Dβ (the state shown in Figure 8) as the reference length Yref. The controller 25 also detects the extension amount ΔY of the telescopic cylinder 10 from the reference length Yref.

In this modified example, when the detector 17 begins detecting the detection plate Dβ (D4) in the state shown in Figure 8, the controller 25 determines whether the extension amount ΔY of the telescopic cylinder 10 from the reference length Yref is within a predetermined range greater than or equal to the lower limit ΔYmin and less than or equal to the upper limit ΔYmax. If the extension amount ΔY is within the predetermined range, the controller 25 determines that the lock pin Rβ (R4) can engage with the lock hole Efα (Ef3) and notifies the user via a user interface (not shown) or the like that the lock pin Rβ can engage with the lock hole Efα. On the other hand, if the extension amount ΔY is outside the predetermined range, the controller 25 determines that the lock pin Rβ (R4) cannot engage with the lock hole Efα (Ef3) and notifies the user via a user interface or the like that the lock pin Rβ cannot engage with the lock hole Efα.

In this modified example, the attachment state of the front section 3 to the rear section 2 is determined in the same manner as in the previously described embodiment. Therefore, as in the previously described embodiment, even if the connection destination of the extended end of the cord 22 is changed when the multi-stage boom 1 is fully retracted, it is possible to appropriately determine whether the front section 3 is attached to the rear section 2. Therefore, the operation of the multi-stage boom 1 is appropriately and safely controlled depending on whether the front section 3 is attached to the rear section 2, and the process of changing the connection destination of the extended end of the cord 22 is simplified.

In addition, in this modified example, the controller 25 determines whether the lock pin Rβ (R4) of the boom member Bβ (B4) can engage with the lock hole Efα (Ef3) of the boom member Bα (B3), and notifies the user of the determination result. This makes it easier to adjust the positions of the lock pin Rβ (R4) and the lock hole Efα (Ef3) when attaching the front section 3 to the rear section 2. This improves work efficiency when attaching the front section 3 to the rear section 2.

In the second modified example shown in FIG. 9 , in addition to detection plate Dβ (D4), detection plate P is provided on the rearmost boom member (first telescopic boom member) Bβ in the front section 3 as an object to be detected by the detector 17. Detection plate P is not misaligned or is barely misaligned with detection plate Dβ in the longitudinal direction of the multi-stage boom 1. However, the detection range of detection plate P by detector 17 is smaller than the detection range of detection plate Dβ (D4) by detector 17 and is included within the detection range of detection plate Dβ (D4) by detector 17. Therefore, when detector 17 is detecting detection plate P, it is also detecting detection plate Dβ. In other words, the detector 17 will not detect only detection plate P without detecting detection plate Dβ.

In this modified example, when the detector 17 is detecting the detection plate Dβ (D4), the controller 25 determines whether the detector 17 is detecting the detection plate P. If the detector 17 is detecting the detection plate P, the controller 25 determines that the lock pin Rβ (R4) can engage with the lock hole Efα (Ef3). On the other hand, if the detector 17 is not detecting the detection plate P, the controller 25 determines that the lock pin Rβ (R4) cannot engage with the lock hole Efα (Ef3). In this modified example, the controller 25 also notifies the user of the determination result regarding the engagement between the lock pin Rβ (R4) and the lock hole Efα (Ef3) via a user interface or the like. In this modified example, the engagement between the lock pin Rβ (R4) and the lock hole Efα (Ef3) is determined and notified, thereby achieving the same functions and effects as the first modified example described above.

In addition, while in the aforementioned embodiments, the rear section 2 is formed from one base boom member (B1) and two telescopic boom members (B2, B3), the rear section 2 may simply include one base boom member and one or more telescopic boom members. Also, in the aforementioned embodiments, the front section 3 is formed from three telescopic boom members (B4-B6), but the front section 3 may simply include one or more telescopic boom members. In these cases, the attachment state (connection state) between the front section 3 and the rear section 2 is determined in the same manner as in the aforementioned embodiments. Therefore, the same functions and effects as in the aforementioned embodiments are achieved.

Furthermore, the rear section 2 may be capable of selectively attaching any one of two or more types of front sections. In this case, whether or not a front section is attached to the rear section 2 is determined in the same manner as in the previously described embodiment during the process of attaching any one of the types of front sections to the rear section 2 and during the process of separating the front section attached to the rear section 2 from the rear section 2. Therefore, the same functions and effects as in the previously described embodiment are achieved. Note that when any one of two or more types of front sections can be selectively attached to the rear section 2, the two or more types of front sections may differ from one another in one or more of the following: the number of boom members (telescopic boom members), longitudinal length, weight, etc. In other words, the two or more types of front sections may be the same in the number of boom members (telescopic boom members) provided, as long as they differ from one another in one or more of the following: longitudinal length, weight, etc.

The present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the various embodiments may be implemented in combination as appropriate as possible, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining the multiple disclosed constituent elements.

1...multi-stage boom, 2...rear section, 3...front section, 10...telescopic cylinder, 12...cylinder tube, 17...detector (first detector), 18...detector (second detector), 20...boom control device, 22...cord, 23...connector, 25...controller, Bi, Bj...boom members, Dk...detection plate.

Claims (6)

A boom control device for controlling the operation of a multi-stage boom, comprising: a rearmost base boom member; and a plurality of telescopic boom members that are extendable and retractable in the longitudinal direction relative to the base boom member; and a front section formed of one or more of the telescopic boom members detachably attached to a rear section formed of the base boom member and one or more of the telescopic boom members,
a cord extending from the rear portion and having an extended end connectable to the front portion;
a telescopic cylinder selectively connectable to one of the telescopic boom members and extending or retracting the connected telescopic boom member by telescoping;
a first detector that moves along the longitudinal direction by the extension and retraction operation of the telescopic cylinder and is attached to the first telescopic boom member, which is the rearmost telescopic boom member in the front section, and detects a detection target by proximity;
a controller that determines that the front section is attached to the rear section based on whether the first detector detects the object to be detected on the first telescopic boom member, when the extended end of the cord is connected to the rear section and the telescopic cylinder is connected to the second telescopic boom member which is the frontmost telescopic boom member in the rear section, and controls the operation of the multi-section boom, including extension and contraction of the multi-section boom, based on the determination result of whether the front section is attached to the rear section;
A boom control device comprising: The boom control device of claim 1, wherein the controller determines that the front section is separated from the rear section based on the first detector not detecting the detection target of the first telescopic boom member when the extended end of the cord is connected to the rear section and the telescopic cylinder is connected to the second telescopic boom member. The boom control device of claim 1 or 2, wherein the controller determines that the front section is attached to the rear section based on whether the telescopic cylinder is connected to any of the telescopic boom members in the front section, including the first telescopic boom member, when the extended end of the cord is connected to the rear section. A boom control device according to any one of claims 1 to 3, wherein the controller determines that the forward portion is attached to the rearward portion based on the fact that the extended end of the cord is connected to the forward portion. a second detector that moves along the longitudinal direction due to the extension and retraction operation of the telescopic cylinder and detects, by proximity, detection objects provided on each of the telescopic boom members, including the detection object on the first telescopic boom member, and is disposed rearward and spaced apart from the first detector;
When the second detector detects the detection object of any one of the telescopic boom members, the telescopic cylinder is connected to the telescopic boom member that is detected by the second detector, or is located at a position in the longitudinal direction where the detection object can be connected to the telescopic boom member that is detected by the second detector.
The boom control device according to any one of claims 1 to 4. A boom control device according to any one of claims 1 to 5, wherein when the controller determines that the front section is attached to the rear section while the extended end of the cord is connected to the rear section, the controller determines that the first telescopic boom member of the front section is the frontmost section of the multi-stage boom and controls the operation of the multi-stage boom, including the extension and retraction of the multi-stage boom.