JP3233917B2 - Multi-stage telescopic arm - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-stage telescopic arm for a construction machine or the like.

[0002]

2. Description of the Related Art Conventionally, for example, many construction machines for excavating a deep foundation have a multistage telescopic arm as shown in FIG. The structure of such a construction machine will be described with reference to FIG. 16. The construction machine 1 is provided with an upper swing body 9 that can swing freely on a lower traveling body 8, and can swing vertically on the upper swing body 9. And a multi-stage telescopic arm which is also swingable in the vertical direction at the tip thereof. For example, in the case of a three-stage telescopic arm, the multi-stage telescopic arm includes a base arm 3, a second-stage arm 4, and a third-stage arm 5. An excavating bucket such as a hydraulic clam bucket 7 is provided at the end of the third-stage arm 5, for example. The clam bucket 7 is driven to open and close by a hydraulic cylinder (not shown).

[0003] During excavation work, the construction machine 1 moves the ground surface G. L
The boom 2 and the multi-stage telescopic arm are set on the top, and are swung to the excavation posture. When the base arm 3, the second arm 4, and the third arm 5 extend to reach the depth at which the hydraulic clam bucket 7 is excavating, the clam bucket 7 is operated and soil and the like are removed. 7. Thereafter, each arm is reduced, and the clam bucket 7 is moved to the ground surface G. Lifted to near L, and boom 2
Is swung to the position of the boom 2a and the base arm 3
Is pulled up to the position of the base arm 3a. Next, the upper swing body 9 of the construction machine 1 is swiveled to a predetermined position, and the base arm 3 is swung to the position of the base arm 3b. Is loaded. Until the trench is at the desired drilling depth
The above operation is repeated.

In order to extend and retract such a multi-stage telescopic arm, for example, a driving device as shown in FIG. 17 is generally used. Hereinafter, the configuration and operation of the conventional driving device will be described with reference to FIG. FIG. 17 shows an example in which a hydraulic cylinder 10 is used as a driving device, and the hydraulic cylinder 10 is a base arm 3, a second arm 4 and a third arm 3.
It is provided inside the step arm 5. The rod mounting end 10a of the hydraulic cylinder 10 is fixed to the upper end of the base arm 3,
On the other hand, the rod-side end (tube mounting end) 10b of the tube of the hydraulic cylinder 10 is fixed to the upper end of the second-stage arm 4, and is a so-called trunnion type attachment. The sheave 11 is at the upper end of the second stage arm 4 and
The sheave 12 is provided so as to be built inside.
It is provided at the lower end of the step arm 4. The wire rope 13, one end of which is fixed at the inner lower end 13 a of the base arm 3, is guided to the third arm 5 through the fixed sheave 11, and the other end of the wire rope 13 is connected to the third arm. 5
Is fixed at the upper end 13b. A wire rope 14 having one end fixed to an outer lower end 14a of the base arm 3
Is guided to the third arm 5 via the fixed sheave 12, and the other end of the wire rope 14 is fixed at the upper end 14 b of the third arm 5.

When the hydraulic cylinder 10 is extended, the second stage arm 4 is lowered by the driving force, and the fixed sheave 12 is moved downward accordingly. By this movement, one end 14b of the wire rope 14 is pushed down, and the third arm 5 is driven downward. The hydraulic cylinder 10
Is reduced, the second-stage arm 4 is pulled upward,
The fixed sheave 11 moves upward. By this movement, one end 13b of the wire rope 13 is pulled upward, and 3
The step arm 5 is driven upward. At this time, the driving force to be lifted upward is transmitted to the hydraulic cylinder 10, the second-stage arm 4, the fixed sheave 11, the wire rope 13, the third-stage arm 5, and the clam bucket 7 in this order.

[0006]

In the conventional multi-stage telescopic arm driving device as described above, since the driving force for pulling up the multi-stage telescopic arm acts on the wire rope 13, the wire rope 13 is gradually used during use. Tired,
It may be broken at the end of its life. If the wire rope 13 is broken, the third stage arm 5 and the clam bucket 7 may fall, which is extremely dangerous. In addition, since the wire rope 13 is inside the base arm 3 and the second arm 4, it takes a very long time to replace the broken wire rope 13, and the workability at the time of replacement is not very good.

For this reason, it is strongly required to predict the life of the wire rope as well as to improve the life. As a method of performing this prediction, conventionally, fixed sheaves 11, 1
There is a method of counting the number of rotations of 2 and determining that the life is reached when the number of rotations reaches a predetermined number of rotations, and there is a method of outputting an alarm or an instruction to replace the wire rope 13 when the life is determined. However, in this method, the wire rope 13
It is not possible to take into account factors such as the magnitude of the load and trauma that greatly affect the life of the device. Therefore, the life is predicted in vain, and the frequency of replacement of the wire rope 13 is increased, or there is a possibility that an unexpected disconnection may be caused due to a sudden cause.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and has as its object to provide a multi-stage telescopic arm which can predict the life of a wire rope and improve the maintainability of the wire rope.

[0009]

In order to achieve the above object, a first invention of a multi-stage telescopic arm according to the present invention is a multi-stage telescopic arm comprising: In a multi-stage telescopic arm driven to be extendable and retractable by a wire rope, a pair of right and left sheaves mounted on the arm of the predetermined stage and one end are fixed to an arm before or after the arm of the predetermined stage, The other end is rotatably attached to a pair of wire ropes respectively guided by the pair of sheaves and an arm at a stage subsequent to or at a stage preceding the arm of the predetermined stage, and is connected to a connection end distributed by a rotation center. the 1 and the other end of the pair of the wire rope is connected, has a configuration in which a equalizer to equalize the load applied to the connecting end the pair of wire rope by the rotation of the .

[0010] According to the first invention, the left arm is provided at the predetermined stage.
A pair of right sheaves is provided, and the arm of the predetermined stage is driven in a suspended state by a pair of wire ropes respectively guided to an arm at a stage preceding or subsequent to the arm of the predetermined stage via the pair of sheaves. ing. At this time, since the connecting one end of the wire rope to be paired with the arm through the equalizer, it is possible to apply a load to the wire rope to be the pair equally. When one of the wire rope is weak compared to the other (easily stretched rope against tensile load), go elongation gradually weaker wire rope, gradually turning angle of the equalizer Accordingly growing. Therefore, based on the strength of a pair of wire ropes,
The fatigue of the wire rope can be detected from the rotation angle of the moving equalizer . Also, since the life of the weaker wire rope is shorter than the other wire rope,
The weaker ones are more likely to break. Since the rotational angle of the equalizer when life approaches approaches the predetermined angle, also it becomes possible to predict the life of visually or the like, it is replacement of the wire rope before breaking. Thereby, breakage of the wire rope can be prevented beforehand, and workability at the time of replacing the wire rope can be improved.

[0012] In a second aspect based on the first aspect, the icon
The riser is an equalizer bar, and is provided with a detector for detecting the inclination angle thereof .

According to the second aspect of the present invention, since the inclination angle of the equalizer bar is detected by the angle detector, the life can be predicted (automatically or visually) based on the detected inclination angle, Or to be notified. This makes it possible to easily manage the life of the wire rope accurately, reliably prevent the wire rope from being cut, increase the life prediction accuracy of the wire rope, reduce the frequency of replacement, and reduce the maintenance cost.

[0013] In a third aspect of the present invention, in the second aspect, a notifying means for notifying when the angle detector detects that the equalizer bar is tilted by a predetermined angle or more is provided.

According to the third aspect, when the equalizer bar is inclined by a predetermined angle or more, the notifying means automatically notifies the operator or the external control device of the replacement timing of the wire rope. Therefore, it is possible to accurately know the replacement time of the wire rope, and it is possible to reliably prevent the wire rope from being cut.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments will be described in detail with reference to the drawings.

An embodiment will be described with reference to FIGS. 1, 2, 3 and 4. The present invention has a structure in which it is possible to easily determine that the life of the wire rope is nearing by using a pair of the arm driving sheave and the corresponding wire rope.

First, the configuration of a three-stage telescopic arm according to the present invention will be described with reference to FIGS. 1 and 2
Shows a side view of the three-stage telescopic arm and a Y view of FIG. The lower part of the base arm 3 of the three-stage telescopic arm is swingably mounted via a boom mounting portion 3g on the tip of a boom 2 which can swing vertically in a construction machine or the like. The hydraulic cylinder 10 is used as an example of the arm expansion / contraction drive device 60. The hydraulic cylinder 10 is incorporated in the third arm 5 at the final stage and the second arm 4 before the latter. Rod attachment end 10a of hydraulic cylinder 10
Is mounted on the upper end of the second-stage arm 4, while the tube mounting end 10b of the hydraulic cylinder 10 is mounted on the upper end of the third-stage arm 5 (trunnion-type mounting structure).

A pair of lifting sheaves 2
2, 22 are provided at the lower end of the second stage arm 4,
The fixed sheaves 22 are disposed on both left and right sides so as to sandwich the third arm 5 as viewed from the boom 2. One end of each of the connection ends 26a, 26
A pair of wire ropes 26, 26 for pulling up the second arm 4 connected at 6a are guided to the third arm 5 through the inside of the second arm 4 via the fixed sheaves 22, 22, respectively. The other ends of the wire ropes 26, 26 are connected to a pair of connection ends 26b, 26b at the outer upper end of the third-stage arm 5, respectively.

A pair of fixed sheaves 24 for depression are provided at the upper end of the second arm 4, and the fixed sheaves 24 are arranged on the left and right as viewed from the boom 2. . A pair of second-stage arm 4 wire ropes 28, 28 having one ends connected to a pair of connection ends 28a, 28a at the inner lower end of the base arm 3, respectively, are connected via fixed sheaves 24, 24, respectively. Through the inside of the second stage arm 4 to the third stage arm 5, and the wire rope 28,
The other ends of the connecting arms 28 are connected to a pair of connecting ends 28b, 28b at the outer upper end of the third-stage arm 5, respectively.

The operation of the above configuration will be described below. When the hydraulic cylinder 10 is extended, the third-stage arm 5 is lowered by the driving force so as to protrude from the lower portion of the second-stage arm 4. Accordingly, a pair of wire ropes 2 connected to the connection ends 28b, 28b at the upper end of the third stage arm 5
8 and 28 are pulled downward and the fixed sheaves 24 and 24 are respectively pushed down, so that the second arm 4 descends so as to protrude from the lower part of the base arm 3.
When the hydraulic cylinder 10 contracts, the third-stage arm 5
Rises and is drawn into the second-stage arm 4, whereby the pair of wire ropes 26, 26 connected to the connection ends 26 b, 26 b at the upper end of the third-stage arm 5 are pulled upward. At this time, since the fixed sheaves 22 are respectively lifted upward, the lower part of the second-stage arm 4 comes closer to the lower end of the base arm 3, and as a result, the second-stage arm 4 is placed inside the base arm 3. It is drawn into and rises.

According to such a configuration, the driving force for pulling up and the load of the arms and the clam bucket 7 in the second and subsequent stages act on the pair of wire ropes 26, 26. Therefore, in order to extend the life of the pair of wire ropes 26, 26, it is necessary to increase the diameter of the pair of fixed sheaves 22, 22 as the diameter of the wire rope increases. Since the fixed sheaves 22, 22 are provided outside the second-stage arm 4 as described above, the diameter thereof can be arbitrarily set without being limited by the inner width of the arm.
As a result, the diameter of the wire rope can be increased as compared with the related art, and the radius of curvature of the wire rope 26 can be increased, so that the life of the wire rope 26 can be greatly improved. Further, as a result, the number of times of replacement of the wire rope 26 is reduced, so that maintainability is also improved. Even if the hydraulic cylinder 10 has another mounting structure different from the above-described trunnion type, the operation and the effect do not change.

Next, a pair of wire ropes 2 according to the present invention will be described.
Connection ends 26a, 2 at the outer lower end of the base arm 3,
The structure for attaching to 6a will be described. FIG. 3 shows a schematic side view of the arm. In this figure, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals, and the description thereof will be omitted. In addition, the positions of the fixed sheave for driving the arm and the connection position of the wire rope are shown in FIGS. It is not shown because it is the same as. A pair of fixed sheaves 22
Provided at the lower end of the step arm 4 and viewed from the boom 2
The step arm 5 is disposed on the left and right sides so as to sandwich the step arm 5. One end of each of the two pulling wire ropes 26, 26 is 3
A pair of connection ends 26b, 26b at the outer upper end of the step arm 5
The other end passes through the inside of the second-stage arm 4 and is guided to the outer lower end of the base arm 3 via a pair of fixed sheaves 22. An equalizer bar 40 is provided at the outer lower end of the base arm 3, and the other ends of the wire ropes 26, 26 are connected to a pair of connection ends 26 a, 26 a at both left and right ends of the equalizer bar 40, respectively. Is done.

FIG. 3 is a detailed view of the equalizer bar 40, that is, FIG.
4 is shown in FIG. 4, and the equalizer bar 40 will be described in detail with reference to FIG. A support shaft 43 that is substantially perpendicular to the moving direction of each arm is provided on the outer lower end of the base arm 3.
The equalizer bar 40 is provided rotatably around the support shaft 43 as a fulcrum. A pair of wire ropes 2
The other end of each of the equalizer bars 6 and 26 is viewed from the boom 2 by the equalizer bar 4.
0 are connected to the connection ends 26a, 26a at both left and right ends, respectively. Stoppers 41, 41 are provided on the lower left and right sides of the equalizer bar 40 so that the rotation of the equalizer bar 40 stops when the equalizer bar 40 rotates by a predetermined angle. Further, in the present embodiment, the left and right stoppers 41
Detectors 42, 42 are attached to the side surfaces of. The detector 42 detects that the equalizer bar 40 has rotated by a predetermined angle, and includes, for example, a limit switch and a proximity switch. Note that the detector 42 may detect that the equalizer bar 40 has rotated and hit the stopper 41.

Next, the operation in such a configuration will be described. First, when a predetermined load is applied to the two wire ropes 26, 26, the equalizer bar 40 is adjusted with screws or the like at the connection ends 26a, 26a of the wire ropes 26, 26 so as to be substantially horizontal. During the work with the multi-stage telescopic arm, the load is evenly applied to the two wire ropes 26, 26, so that the equalizer bar 40
Keeps a substantially horizontal state. As the frequency of use increases, the one of the two wire ropes 26, 26, which has a longer life, gradually weakens against the tensile load, so that it gradually extends.
Its cross section becomes thinner. When one of the wire ropes 26 is slightly extended, the equalizer bar 40 is slightly tilted so that the load is evenly applied to the two wire ropes 26, 26, and the equalizer bar 40 is balanced at that angle. However, since the cross section becomes thinner, the stretched wire rope 26 becomes weaker against the tensile load than before, and thus the wire rope 26 becomes easier to stretch. In this manner, one of the wire ropes 26 has a thinner cross section than the other wire ropes 26, and the deterioration proceeds. Accordingly, the inclination angle of the equalizer bar 40 gradually increases.

Therefore, by visually observing the inclination angle of the equalizer bar 40, it can be easily determined that the life of the wire rope 26 is approaching. Therefore, when the service life is approaching, it is possible to replace the wire rope 26 only in a deteriorated state or both of them before breaking. And
At the time of replacement, the old wire rope 26 before replacement and the new wire rope 26 can be connected to each other, and the old wire rope 26 can be dragged, so that the new wire rope 26 can be passed through the arm. Exchange work can be easily performed. Therefore, maintainability and maintainability of the wire rope 26 are improved.

Then, if one of the wire ropes 26
When the end of the life is broken, the equalizer bar 40 rotates and stops until it hits the stopper 41. At this time,
The other wire ropes 26 will support the full load,
Since the wire rope 26 has almost the original strength, it does not break even if it is supported by this one wire rope. Therefore, there is no danger of falling of the clam bucket 7, etc., and it is very safe.

When the mounting positions of the stoppers 41, 41 are set so that the equalizer bar 40 hits either of the right and left stoppers 41 before the wire rope 26 breaks at the end of its life, the left and right detectors 42, 42 It is possible to detect that the life of the wire rope 26 is approaching.
Using such detectors 42, 42, for example, a lamp, a buzzer, or the like is operated, or a message or the like is displayed or transmitted by inputting to a controller (not shown) using, for example, a microcomputer. This makes it possible to automatically notify the operator or another external control device of the replacement timing of the wire rope. The detectors 42, 42
When a limit switch, a proximity switch, or the like is used for the switch, a circuit that can operate the lamp, the buzzer, and the like by the output contact signal can be easily configured. For example, although not shown in the circuit diagram, when the a contacts of the left and right limit switches are connected in parallel and this parallel circuit is connected in series with a power supply and a lamp (or a buzzer or the like), the left or right limit switch operates. By doing so, a lamp (or a buzzer or the like) can be configured to operate.

Further, in the above embodiment, the example in which the lifting wire rope is connected to the equalizer bar has been described. However, the present invention is not limited to this, and the equalizing bar is similarly connected to the pushing wire rope. The same operation and effect can be obtained even if it is provided.

In the above embodiment, the case of a three-stage telescopic arm has been described as an example of a multi-stage telescopic arm. However, the present invention is not limited to this. However, the operation and effect are the same. 5 and 6 are a side view and FIG.
FIG. Base arm 3 of 4-stage telescopic arm
The lower part is a boom 2 that can swing up and down such as construction machinery.
Is swingably attached to the distal end portion via a boom mounting portion 3g. Here, the hydraulic cylinder 10 is used as an example of the arm expansion / contraction drive device 60, and the hydraulic cylinder 10 is built in the fourth arm 6 at the final stage and the third arm 5 before this. The rod mounting end 10a of the hydraulic cylinder 10 is mounted on the upper end of the third stage arm 5, while the tube mounting end 10b of the hydraulic cylinder 10 is mounted on the upper end of the fourth stage arm 6. Further, fixed sheaves 21 and 22 for lifting are provided at the lower end of the third-stage arm 5 and the lower end of the second-stage arm 4, respectively. In this embodiment, as can be seen from FIG. 6, two fixed sheaves 21 and 22 are provided, and the fixed sheaves 21 and 21 are provided on both the left and right sides so as to sandwich the fourth-stage arm 6 when viewed from the boom 2. The fixed sheaves 22 are disposed on the left and right sides, respectively, so as to sandwich the third arm 5 as viewed from the boom 2.

A wire rope 25 for pulling up the third-stage arm 5, one end of which is connected at a connection end 25 a at the outer lower end of the second-stage arm 4, is connected to the inside of the third-stage arm 5 via the fixed sheave 21. Then, the other end of the wire rope 25 is connected to a connection end 25b at the outer upper end of the fourth arm 6. A wire rope 26 for pulling up the second-stage arm 4, one end of which is connected at a connection end 26 a at the lower end of the outside of the base-stage arm 3, passes through the inside of the second-stage arm 4 via the fixed sheave 22. And the other end of the wire rope 26 is connected to the third arm 5.
Are connected at the connection end 26b at the upper end of the outside.

The fixed sheaves 23 and 24 for pressing are provided at the upper end of the third-stage arm 5 and the upper end of the second-stage arm 4, respectively. In the present embodiment, the fixed sheaves 23, 24
Are shown in the figure. This 2
Fixed sheaves 23, 23 and fixed sheaves 24, 2 each
Reference numeral 4 denotes a left and right side when viewed from the boom 2, and is disposed at a position where the third arm 5 and the second arm 4 are lifted and the whole arm is in the most contracted state and does not interfere with each other.

A wire rope 27 for pushing down the third arm 5, one end of which is connected at a connection end 27 a at the lower end of the inside of the second arm 4, is connected to the third arm 5 via the fixed sheave 23. The wire rope 27 is guided to the fourth-stage arm 6 through the inside, and the other end of the wire rope 27 is connected to a connection end 27 b at the upper end of the outside of the fourth-stage arm 6. A wire rope 28 for pushing down the second-stage arm 4, one end of which is connected at the connection end 28 a at the lower end of the inside of the base arm 3, passes through the inside of the second-stage arm 4 via the fixed sheave 24. Then, the other end of the wire rope 28 is connected to a connection end 28b at the outer upper end of the third stage arm 5.

The operation of the above configuration will now be described.
First, when the hydraulic cylinder 10 is extended, the fourth stage arm 6 is pushed down by the driving force so as to protrude from the lower part of the third stage arm 5. Accordingly, the wire rope 27 connected to the connection end 27b at the upper end of the fourth arm 6 is pulled downward. At this time, fixed sheave 2
Since 3 is pushed down, the third arm 5 is pushed down so as to protrude from the lower part of the second arm 4. Further with this, the wire rope 28 connected to the connection end 28b at the upper end of the third-stage arm 5 is pulled downward. Then, since the fixed sheave 24 is pushed down, the second-stage arm 4 is pushed down so as to protrude from the lower portion of the base arm 3.

When the hydraulic cylinder 10 is contracted, the fourth stage arm 6 is pulled upward and is drawn into the third stage arm 5. Accordingly, the wire rope 25 connected to the upper end connection end 25b of the fourth arm 6 is pulled upward. At this time, since the fixed sheave 21 is pulled up, the lower end of the third-stage arm 5 comes closer to the lower end of the second-stage arm 4. Drawn into. Further with this, the wire rope 26 connected to the connection end 26b at the upper end of the third-stage arm 5 is pulled upward. At this time, since the fixed sheave 22 is pulled up, the lower end of the second-stage arm 4 approaches the lower end of the base arm 3, and as a result, the second-stage arm 4 is drawn into the base arm 3. It is.

According to the above configuration, the driving force for pulling up and the load on the second and subsequent arms and the clam bucket 7 act on the wire ropes 25 and 26. Therefore, in order to improve the life of the wire rope 25 and the wire rope 26, it is necessary to increase the diameter of the fixed sheaves 21 and 22 as the diameter of the wire rope increases. Fixed sheaves 21, 22 as described above
Is provided outside the third-stage arm 5 and the second-stage arm, the diameter thereof can be arbitrarily set without being restricted by the inner width of the arm. As a result, the diameter of the wire rope can be increased and the radius of curvature of the wire rope can be increased as compared with the related art, so that the life of the wire rope can be greatly improved. Further, as a result, the number of times of replacing the wire rope is reduced, so that maintainability is also improved. Even in the case of the above-described four-stage telescopic arm, a pair of connection ends 25a and 25a of the second-stage arm 4 and a pair of connection ends 26a and 26a of the base-stage arm 3 are used. At least one of the connection ends 27a, 27a and at least one of the pair of connection ends 28a, 28a of the base arm 3 is connected to the equalizer bar 40 in the same manner as in the above embodiment.
May be provided at both ends.

In the above embodiment, the fixed sheave 22,
Although 22 is provided at the lower end of the second-stage arm 4, the present invention is not limited to this, and may be provided below the second-stage arm 4, for example, as shown in FIGS. 7 and 8.

7 and 8 show a side view of the four-stage telescopic arm of the embodiment in another sheave position and a U view of FIG. 7, respectively. Here, the same components as those in FIGS. 5 and 6 are denoted by the same reference numerals, and description thereof is omitted. 2
The fixed sheave 22 for lifting the stage arm 4 is rotatably mounted below the second stage arm 4. One end was connected at a connection end 26a at the outer lower end of the base stage arm 3,
The wire rope 26 for lifting the second-stage arm 4 passes through the inside of the second-stage arm 4 via the fixed sheave 22, and
The other end of the wire rope 26 is connected to the outer end of the third arm 5 at a connection end 26b. The fixed sheave 21 for lifting the third-stage arm 5 is rotatably mounted below the third-stage arm 5. One end is a connection end 25 at the lower end of the outside of the second stage arm 4
The wire rope 25 for pulling up the third arm 5 connected at a is guided to the fourth arm 6 through the inside of the third arm 5 via the fixed sheave 21, and the wire rope 25 Is connected to a connection end 25b at the upper end of the outside of the fourth arm 6. In the present embodiment, similarly to the above, two fixed sheaves 22 are provided on the left and right of the second arm 4 as viewed from the boom 2, and two fixed sheaves 21 are provided on the left and right of the third arm 5. The fixed sheaves 22 and 22 and the fixed sheaves 21 and 21 each have 2
Holes 4 a, 4 a and holes 5 a, 5 a are provided at positions that go outside from the step arm 4 and the third step arm 5. Then, the fixed sheaves 22, 22 and the fixed sheaves 21, 2,
The lower part of 1 is protected from interference with the outside by guards 72, 72 and guards 71, 71 provided outside the lower part of the second-stage arm 4 and the third-stage arm 5, respectively.

A pad 75 is attached to the lower end of the inner surface of the second stage arm 4. FIG. 9 is a cross-sectional view taken along the line CC of FIG. A pad 75 is provided at the lower end of the inner surface of the second-stage arm 4. The pad 75 is provided on the third-stage arm so that there is no play between the lower end of the second-stage arm 4 and the third-stage arm 5. 5 is uniformly in contact with the outer surface. Further, similarly, a pad 76 is mounted on the upper end of the outer surface of the third arm 5, and this pad 76 has no backlash between the upper end of the third arm 5 and the second arm 4. As described above, the second stage arm 4 is provided in uniform contact with the inner surface. These pads 75 and 76 are attached with screws or the like, so that they can be easily attached and detached during maintenance when the pads are worn. Similarly, a pad 73 is provided at the lower end of the inner surface of the third-stage arm 5, and the pad 73 uniformly contacts the outer surface of the fourth-stage arm 6. A pad 74 is attached to the upper end of the outer surface of the fourth arm 6.
The pad 74 is provided in uniform contact with the inner surface of the third-stage arm 5.

In the multistage telescopic arm having such a configuration, the operation at the time of expansion and contraction is the same as in the case described above. That is, when the hydraulic cylinder 10 as the driving device 60 is reduced, the third-stage arm 5 moves up via the wire rope 25 and the fixed sheave 21, and accordingly, the second stage arm 5 moves through the wire rope 26 and the fixed sheave 22. The arm 4 moves up.
When the hydraulic cylinder 10 extends, the third-stage arm 5 descends via the wire rope 27 and the fixed sheave 23, and accordingly, the second-stage arm 4 descends via the wire rope 28 and the fixed sheave 24.

In this case as well, the driving force for pulling up and the loads on the second and subsequent arms and the clam bucket 7 act on the wire ropes 25 and 26 in the same manner as described above. Since the diameter of the fixed sheaves 21 and 22 can be arbitrarily large without being restricted by the inner width of the arm and the like, the diameter of the fixed sheaves 21 and 22 can also be increased. As a result, the wire diameter of the wire rope 25 and the wire rope 26 can be increased and the radius of curvature of the wire rope can be increased as compared with the related art, so that the life of the wire rope can be greatly improved. Further, as a result, the number of times of replacing the wire rope is reduced, so that maintainability is also improved. As shown in FIG. 7, the wire ropes 25 and 26 do not necessarily have to be parallel to the longitudinal axis of each arm. The fixed sheaves 21 and 21 and the fixed sheaves 22 and 22 are connected to the third arm 5 and the second arm 4 respectively.
The pad 73 and the pad 7 are provided above the lower end of the pad.
5 can be easily replaced and maintenance workability is good. Further, since the guards 72, 72 and the guards 71, 71 are also provided, the fixed sheaves 21, 21 and the fixed sheave 22,
The contact between the arm 22 and an external obstacle from below each arm can be eliminated. Even in the case of the four-stage telescopic arm at the sheave position as described above, the second-stage arm 4
, A pair of connection ends 26 a, 26 a of the base arm 3, a pair of connection ends 27 a, 27 a of the second arm 4, and a pair of connection ends of the base arm 3. 28
A pair of connection ends of at least one of a and a may be provided at both ends of the equalizer bar 40 as in the above-described embodiment.

Next, another embodiment using a device other than the hydraulic cylinder as the arm driving device 60 will be described.
First, FIGS. 10 and 11 show an example in which a rack and a pinion are provided and the pinion is rotated by a drive motor. FIG. 10 is a schematic side view of the arm, and FIG. 11 is a sectional view taken along line AA of FIG. 10 showing details of a rack and a pinion portion. In these figures, the same components as those in FIG. 5 are denoted by the same reference numerals, and are the same as those described so far. Therefore, the driving device 60 will be described here. The drive motor 32 is mounted on the upper end of the fourth stage arm 6 at the last stage, and the pinion 31 is mounted on the rotation shaft of the drive motor 32. The direction of the rotation axis of the drive motor 32 is orthogonal to the direction of movement of the fourth arm 6, and the outer dimensions of the drive motor 32 and the pinion 31 are smaller than the inner width of the cross section of the third arm 5. is there. On the inner surface of the third stage arm 5 just before the last stage,
A rack 30 is provided in parallel with the moving direction of the fourth arm 6,
The rack 30 is mounted so as to mesh with the pinion 31. The drive motor 32 may be, for example, a hydraulic motor or an electric motor. Further, the positions of the fixed sheave for driving the arm and the connection position of the wire rope and the like are the same as those in the above-described embodiments, and are omitted in the drawings, and description thereof is omitted.

The operation in the above configuration is as follows. When the drive motor 32 rotates and the fourth stage arm 6 moves so as to protrude downward by the rack 30 and the pinion 31, the operation is the same as when the hydraulic cylinder is extended in the case of the hydraulic cylinder described above. When the drive motor 32 rotates, the fourth-stage arm 6 becomes the third-stage arm 5.
When the hydraulic cylinder rises so as to be drawn inside, the operation is the same as when the hydraulic cylinder is contracted.

FIGS. 12 and 13 show an embodiment of a driving device in which a chain and a sprocket are provided and the sprocket is rotated by a driving motor. FIG.
FIG. 13 is a schematic side view of the arm, and FIG. 13 is a sectional view taken along the line BB of FIG. 12 showing details of the chain and the sprocket portion. 5, the same components as those in FIG. 5 are denoted by the same reference numerals, and description thereof will be omitted. Hereinafter, the driving device 60 will be described. A drive motor 35 is provided on the upper end of the fourth arm 6 at the last stage.
Is mounted, and the sprocket 34 is mounted on the rotation shaft of the drive motor 35. The direction of the rotation axis of the drive motor 35 is orthogonal to the direction of movement of the fourth arm 6, and the outer dimensions of the drive motor 35 and the sprocket 34 are smaller than the inner width of the cross section of the third arm 5. is there. A chain 33 is provided on the inner surface of the third stage arm 5 just before the final stage in parallel with the moving direction of the fourth stage arm 6, and the chain 33 is attached so as to mesh with the sprocket 34. The fixed sheave arrangement position for arm driving and the wire rope connection position
Since it is the same as the above-described embodiment, illustration and description are omitted.

The operation in the above configuration is the same as that described above. When the drive motor 32 rotates, the sprocket 34 moves downward or upward along the chain 33, whereby the multi-stage telescopic arm extends or contracts.

FIG. 14 and FIG. 15 show an embodiment of a driving device provided with a wire rope and a winch and rotating the winch by a driving motor. FIG. 14 is a schematic side view of the arm, and FIG. 15 is a Z view of FIG. 14 showing details of a wire rope and a winch portion. 5, the same components as those in FIG. 5 are denoted by the same reference numerals, and the description thereof will be omitted. The drive device 60 will be described below. A winch 38 having a built-in drive motor 39 is mounted on the upper end of the fourth arm 6 at the last stage. The directions of the rotation axes of the drive motor 39 and the winch 38 are orthogonal to the moving direction of the fourth arm 6, and the size of the outer shape of the winch 38 is smaller than the inner width of the cross section of the third arm 5. .
The wire rope 36 has one end connected to the winch 38, wound around the winch 38 a predetermined number of times, and the other end connected to the winch 38.
It is connected to the inner upper end of the step arm 5. The wire rope 37 has one end connected to the winch 38, wound around the winch 38 a predetermined number of times in the direction opposite to the wire rope 36, and the other end connected to the lower end inside the third arm 5. The arrangement position of the fixed sheave for driving the arm, the connection position of the wire rope, and the like are the same as those in the above-described examples, and thus illustration and description are omitted.

The operation in the above configuration is the same as described above. When the winch 38 is rotated by the drive motor 39, one of the wire ropes 36 and 37 is wound around the winch 38, and the other rope is unreeled from the winch 38. The winch 38 moves downward or upward along the wire rope and drives the fourth arm 6. Thereby, the multi-stage telescopic arm extends or contracts.

As described above, the other three examples of the driving device 60 operate in the same manner as the example using the hydraulic cylinder. Therefore, similarly to the embodiment described with reference to FIGS. 1 and 5 described above, the pulling wire ropes 25 and 26 are used.
The diameters of the fixed sheaves 21 and 22 relating to the life of the wire ropes can be made arbitrarily large. As a result, the life of the wire ropes 25 and 26 can be improved. Also, in the example using such various driving devices 60, the connection ends of the wire ropes 25 and 26 may be provided at both ends of the equalizer bar 40 described above.

As described above, according to the present invention, the drive between the last arm and the arm immediately before the last stage arm is driven to expand and contract by the driving device built in these arms, and at least the lower part of the above-mentioned immediately preceding arm Since the pulling sheave having a diameter larger than the inner width of the arm is attached to the arm, the diameter of the wire rope and the radius of curvature of the wire rope can be increased as compared with the related art. As a result, the life of the wire rope is dramatically increased, so that the replacement interval of the wire rope due to breakage is extended, and the maintainability is improved.

Since the two pulling wire ropes are connected to the equalizer bar via the two pulling sheaves, when the life of one of the wire ropes becomes short, the inclination angle of the equalizer bar increases. The angle can be visually observed or detected by a detector. Thus, it is possible to determine that the life of the wire rope is near, and to replace the wire rope before breaking. Therefore, it is safe to prevent the bucket or the like from dropping, and it is possible to improve the workability when replacing the wire rope by using the wire rope that is not broken.

[Brief description of the drawings]

FIG. 1 is a side view of a three-stage telescopic arm according to the present embodiment.

FIG. 2 is a Y view of FIG. 1;

FIG. 3 is a schematic side view of a multi-stage telescopic arm for explaining a wire rope mounting structure according to the embodiment.

FIG. 4 is a view as viewed from W in FIG. 3;

FIG. 5 is a side view of an example of a four-stage telescopic arm according to the present invention.

FIG. 6 is an X view of FIG. 5;

FIG. 7 is a side view of a four-stage telescopic arm showing another embodiment of a sheave position.

FIG. 8 is a view as viewed in the direction U in FIG. 7;

FIG. 9 is a sectional view taken along the line CC in FIG. 7;

FIG. 10 is a side view of another embodiment of the driving device.

11 is a sectional view taken along line AA of FIG.

FIG. 12 is a side view of another embodiment of the driving device.

FIG. 13 is a sectional view taken along line BB of FIG.

FIG. 14 is a side view of another embodiment of the driving device.

FIG. 15 is a Z view of FIG. 14;

FIG. 16 is a view for explaining a state of excavation work using a multi-stage telescopic arm according to a conventional technique.

FIG. 17 is a side view of a multi-stage telescopic arm according to the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Construction machine, 2 ... Boom, 3 ... Base arm, 3g ... Boom mounting part, 4 ... Second stage arm, 4a, 5a ... Hole, 5 ...
Third stage arm, 6 ... Fourth stage arm, 7 ... Clam bucket, 8 ... Lower traveling body, 9 ... Upper revolving body, 10 ... Hydraulic cylinder, 10a ... Rod attachment end, 10b ... Tube attachment end, 11, 12, 21, 22, 23, 24 ... fixed sheave, 13, 14, 25, 26, 27, 28, 36, 37
... wire ropes, 24a, 24b, 24c, 24d ... sheaves, 25a, 25b, 26a, 26b, 27a, 27
b, 28a, 28b connection end, 30 rack, 31 pinion, 32, 35, 39 drive motor, 33 chain, 34 sprocket, 38 winch, 40 equalizer bar, 41 stopper, 42 detection 43, support shaft, 60, drive device, 71, 72, guard, 73, 7
4, 75, 76 ... pad, G. L: Ground surface.

Continuation of the front page (56) References JP-A-3-267423 (JP, A) JP-A-5-51939 (JP, A) JP-A-7-172763 (JP, A) JP-A-7-4559 (JP) , U) Jiko 3-30436 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) E02F 3/413 B66C 23/687 E02F 3/39

Claims (3)

(57) [Claims] 1. A multi-stage telescopic arm in which a plurality of stages of arms are sequentially inserted and driven by a wire rope via a sheave mounted on the arm, wherein the arms at predetermined stages are provided. A pair of sheaves (21, 21), (22, 22) attached to the left and right ends, one end of which is fixed to an arm preceding or following the predetermined stage arms (3), (4), and the other end The pair of sheaves (21, 21),
A pair of wire ropes respectively guided by (22,22)
(25, 25), (26, 26), and a connection end which is rotatably attached to an arm at a later stage or an earlier stage than the arms (3), (4) at the predetermined stage, and which is distributed by the center of rotation. In addition, the pair of wire ropes (25, 25), (2
6,26) is connected, and the rotation of the connection end
Multistage telescopic arm, wherein more the pair of wire ropes (25, 25), that a equalizer (4 0) to even such load (26, 26). 2. A multi-stage telescopic arms according to claim 1, wherein an equalizer (40) is an equalizer bar, multistage telescopic arm, characterized in that it comprises a detector for detecting the tilt angle of it. 3. The multi-stage telescopic arm according to claim 2, further comprising: a notifying means for notifying when the angle detector detects that the equalizer bar (40) has tilted by a predetermined angle or more. arm.