JP6007766B2 - crane - Google Patents

Description

  The present invention relates to a crane having an extendable boom.

  Conventionally, a crane having an extendable boom is widely known. A crane having such an extendable boom is often used particularly in a narrow construction site because it has good workability and transportability. As a specific configuration of the boom, there is a so-called telescope that has a multi-stage box-shaped boom body that is fitted so as to be movable relative to each other in the axial direction. The scope type is widely known.

  In a crane equipped with such a telescopic boom, as a means for raising and lowering the boom, generally, a hydraulic cylinder interposed between the tip side of the lowermost boom body and the base of the crane is mounted. The hydraulic cylinder moves the entire boom in the standing direction by pushing up the lowermost boom body from below (see, for example, Patent Document 1).

Registered Utility Model No. 3062585

  As described above, the boom supported by the hydraulic cylinder from the bottom is in a so-called cantilever state where the tip is a free end, and is caused by the weight of the boom and the suspended load as the boom extends. The bending moment is increased, and the bending of the boom is increased. If an attempt is made to increase the rigidity of the boom in order to suppress this bending, the structure is naturally complicated and heavy, and the workability and transportability, which are inherent advantages, may be impaired.

  In order to solve the above-mentioned problems, the present inventors, like a so-called lattice boom, connect a hoisting rope drawn out from a hoisting winch to the tip of the boom via a guy line, and wind the line by the hoisting winch. I came up with the idea to raise and lower the boom. With such an undulating drive mechanism, the boom is supported at both ends by a pivot center point (for example, a boom foot pin) on the proximal end side and a connecting point of the line on the distal end side. The deflection is greatly reduced.

  However, when such a hoisting drive mechanism using a winch is applied to an extendable boom, the distance from the tip of the boom to the hoisting winch varies significantly as the boom expands and contracts. Otherwise, the boom will move greatly in the undulation direction as it expands and contracts. That is, it becomes impossible to make the boom expansion / contraction operation and the undulation operation independent. As a means for avoiding such mutual interference between the telescopic operation and the hoisting operation, the hoisting winch is operated in the winding or feeding direction in accordance with the expansion and contraction of the boom to eliminate the influence on the hoisting operation of the boom. Although it is conceivable, the fluctuation of the distance from the tip of the boom to the hoisting winch due to the expansion and contraction of the boom is very large as described above. Therefore, in order to make the operation of the hoisting winch follow the telescopic operation, the hoisting winch Must be driven at high speed and with high frequency. This is not practical considering the large inertial force of the hoisting winch drum.

  An object of the present invention is a crane including an extendable boom, and by using a hoisting winch, the boom can be raised and lowered while suppressing a bending moment acting on the boom, It is an object of the present invention to provide a crane that can effectively suppress interference between the telescopic motion and the hoisting motion of the boom without operating the hoisting winch at high speed.

  A crane provided by the present invention includes a base, a boom that can be raised and lowered to the base, and can extend and contract in the longitudinal direction, an expansion and contraction device that expands and contracts the boom, and a hoisting line that is drawn from the tip of the boom. A hoisting rope connected to the hoisting line, a hoisting winch mounted on the base and operating the boom in the hoisting direction via the hoisting line by winding and unwinding the hoisting rope, and the boom And a line length adjusting mechanism assembled to. The line length adjusting mechanism includes a plurality of sheaves including a tip side sheave attached to the tip of the boom, the undulation line is wound around these sheaves, and the boom can be expanded and contracted. The plurality of sheaves are arranged so that the hoisting line is fed out from the tip sheave and the hoisting line is taken into the tip boom.

  According to this crane, when the hoisting winch winds or unwinds the hoisting rope connected to the hoisting line drawn from the tip of the boom and the boom is operated in the hoisting direction, the tip becomes a free end. Unlike conventional cranes in which the boom is raised and lowered in this state, the bending moment acting on the boom can be reduced, and the line length adjusting mechanism assembled to the boom can be adjusted according to the extension and contraction of the boom. Since the hoisting line is fed out from the tip side sheave attached to the tip of the boom or the hoisting line is taken in, when the hoisting winch is not operated along with the expansion and contraction of the boom, the boom moves in the hoisting direction along with the expansion and contraction. It is possible to effectively suppress movement. In other words, it is not necessary to operate the hoisting winch in order to suppress the influence of the boom extending and retracting operation on the hoisting operation of the boom, or the required speed of the operation can be kept low.

  Preferably, the line length adjusting mechanism feeds the undulation line from the tip sheave by a length corresponding to the extension amount as the boom extends, and adjusts the contraction amount as the boom contracts. It is preferable that the hoisting line is taken into the boom from the tip side sheave by a corresponding length. Such a line length adjusting mechanism eliminates the need for the drive control of the hoisting winch for suppressing the effect of the boom extending and retracting operation on the hoisting operation of the boom, or can greatly simplify the drive control.

  Specifically, the boom includes a plurality of boom bodies arranged in the longitudinal direction of the boom, and these boom bodies are movable relative to the boom body adjacent thereto in the telescopic direction of the boom. The line length adjusting mechanism is a sheave included in the line length adjusting mechanism, and the sheaves other than the distal end side sheave are proximal end ends and distal end ends of the boom bodies. The hoisting line is fixed to a base end side portion connected to the base of the boom and is close to the base end side of the boom with respect to each sheave. It is preferable that the sheave is provided in order from the sheave provided on the boom body and led out of the boom from the tip sheave. This line length adjusting mechanism has a simple structure, and can realize the feeding and taking-in of the undulation line from the tip sheave corresponding to the extension and contraction of the boom.

  In the present invention, in addition to the line length adjusting mechanism, a control device for controlling the operation of the hoisting winch based on the expansion / contraction operation of the boom may be further provided. The control device includes a boom length detector for detecting the boom length, a boom angle detector for detecting the boom undulation angle, and booms detected by the boom length detector and the boom angle detector, respectively. Based on the length and the angle of undulation, a correction amount is calculated to absorb the variation in the distance from the tip sheave to the fulcrum of the undulation rope on the base side as the boom expands and contracts. A winch control unit that operates the hoisting winch based on the amount is preferable. This control device can further reduce the influence of the boom expansion and contraction on the boom hoisting operation. In addition, since the influence is basically reduced by feeding or taking in the undulation line by the line length adjustment mechanism, the correction amount that the control device calculates to suppress the influence on the undulation operation is small. Therefore, it is not necessary to move the hoisting winch at high speed.

  As described above, according to the present invention, a crane including an extendable boom can be used to raise and lower the boom while suppressing a bending moment acting on the boom by using a hoisting winch. In addition, there is provided a crane that can effectively suppress the interference between the boom telescopic operation and the hoisting operation without operating the hoisting winch at high speed.

It is a side view of the crawler crane concerning an embodiment of the invention. It is a cross-sectional front view of the boom in the said crawler crane. It is a top view of the boom. (A) is the figure which showed typically the AA line cross section of FIG. 3, (b) is the figure which showed the BB line cross section of FIG. 3 typically. It is a block diagram which shows the said control apparatus. It is a schematic diagram for demonstrating the principle of the calculation of the correction amount which the said control apparatus performs. It is a flowchart which shows the calculation control operation which the said control apparatus performs.

  A preferred embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows a crane according to an embodiment of the present invention. This crane is a so-called crawler crane, and is a crawler-type lower traveling body 1 and an upper swing that is mounted on the lower traveling body 1 so as to be pivotable about a vertical axis and constitutes a base together with the lower traveling body 1. A body 2, a boom 3 mounted on the front portion of the upper swing body 2 so as to be raised and lowered, a cab 4 disposed on the side of the boom 3, a main winding winch 5, and an auxiliary winding winch 6, A hoisting winch 7, a pair of left and right hoisting lines 8 drawn out from the boom 3, hoisting ropes 9 respectively connected to the hoisting lines 8, and a line length adjustment assembled to the boom 3 And a mechanism. Each of the winches 5, 6 and 7 has a winch drum and a motor for driving the winch drum, and is mounted on the upper swing body 2 so as to be arranged in order from the middle portion to the rear portion of the upper swing body 2.

  The boom 3 according to this embodiment includes a proximal-side structure 31 having a lattice structure, a distal-side structure 32 also having a lattice structure, and a proximal-side structure 31 and a distal-side structure 32. And an extendable intermediate structure 33. The base end side structure 31 is connected to the upper swing body 2 via a boom foot pin 13 so as to be rotatable about a horizontal axis, and the boom 3 as a whole is raised and lowered by the rotation. A main winding sheave 348 and an auxiliary winding sheave 349 are rotatably attached to the tip of the distal end side structure 32, and the main winding hook 34 and the auxiliary winding hook 35 are suspended from the sheaves 348 and 349, respectively. .

  2 to 4 show the structure of the intermediate structure 33. 2 is a cross-sectional side view showing a state in which the intermediate structure 33 is most contracted, FIG. 3 is a plan view thereof, and FIGS. 4A and 4B are taken along lines AA and BB in FIG. It is sectional drawing and shows the structure of the said intermediate structure 33 typically.

  The intermediate structure 33 includes a plurality of boom bodies. The intermediate structure 33 shown in the figure includes a first stage boom body 331, a second stage boom body 332, a third stage boom body 333, and a fourth stage boom body 334 arranged in order from the base end side in a state where the boom 3 is extended. These boom bodies 331 to 334 are hollow box-shaped, and have a shape in which adjacent boom bodies can be fitted in a telescope shape (that is, they can be fitted so as to be movable relative to each other in the expansion and contraction direction of the boom 3).

  The hydraulic cylinders 335, 336, and 337, which are telescopic devices, are provided inside the 2 to 4 stage boom bodies 332, 333, and 334, respectively. Each of the hydraulic cylinders 335 to 337 includes a cylinder main body and an expansion / contraction rod that is displaced in the axial direction, that is, the cylinder expansion / contraction direction with respect to the cylinder main body. 332 to 334 are housed and fixed, and the distal ends of the telescopic rods are respectively fixed to the boom bodies at the level immediately below. Accordingly, the boom bodies 331 to 334 are relatively displaced in the boom longitudinal direction by the expansion and contraction operation of the hydraulic cylinders 335, 336, and 337, and thereby the intermediate structure 33 expands and contracts.

  A plurality of connecting portions 338 and a plurality of connecting portions 339 are provided at the proximal end of the first-stage boom body 331 and the distal end of the fourth boom body 334, respectively. Each connecting portion 338 includes a bracket 338b extending diagonally outward from the four corners of the boom body 338a of the first-stage boom body 331, and an eyepiece 338c fixed to the bracket 338b, and the eyepiece 338c is shown in FIG. The base end structure 31 shown in FIG. Similarly, each connecting portion 339 includes a bracket 339b extending diagonally outward from four corners of the boom body 339a of the four-stage boom body 334, and an eyepiece 339c fixed to the bracket 338b. Is pin-coupled to the distal-end structure 32 shown in FIG.

  As will be described in detail later, the hoisting line 8 is wound around a line length adjusting mechanism assembled to the boom 3 and pulled out from the tip of the boom 3 to the upper swing body 2 side. On the other hand, a gantry 21 is erected at the rear part of the upper swing body 2, and spreaders 22 and 23 are provided at the top of the gantry 21 and at positions spaced from the top toward the boom 3, respectively. The end of the undulation line 8 is connected to the undulation. The portion of the hoisting rope 9 that includes one end is wound around the winch drum of the hoisting winch 7, and the portion that includes the other end is wound between the spreaders 22 and 23. Therefore, the hoisting winch 7 winds or unwinds the hoisting rope 9 by the rotation of the winch drum, so that the tip of the boom 3 passes around the boom foot pin 13 via the hoisting line 8. It is possible to perform the rotation operation, that is, the operation in the undulation direction. Further, the position of the lower spreader 22 corresponds to a fulcrum for supporting the hoisting rope 8 on the upper swing body 2 side constituting the base.

  The line length adjusting mechanism is a pair of left and right tip sheaves 345 provided at the tip of the boom 3 and a plurality of other sheaves, and is assembled to the boom 3 as shown in FIGS. It includes a pair of left and right proximal sheaves 340 and a pair of left and right first to fourth intermediate sheaves 341 to 344, and the undulation line 8 wound around these sheaves extends as the boom 3 extends. The sheaves are arranged so that they are fed out from the tip side sheave 345 by the amount, and conversely, as the boom 3 contracts, the amount of contraction is taken into the boom 3 from the tip side sheave 345, that is, absorbed. ing. In FIG. 4A, the direction of the rotation axis of each sheave 330 to 345 is the left-right direction in the figure, but these sheaves are drawn in small circles for convenience.

  The base end side sheave 340 is housed between the first-stage boom body 331 and the second-stage boom body 332, and a base direction of the second-stage boom body 332 has a specific direction orthogonal to the boom longitudinal direction (this implementation). In the embodiment, the boom 3 is attached so as to be rotatable around an axis in a direction parallel to the rotation center axis of the boom 3. The first intermediate sheave 341 is inclined around the axis in the specific direction at a position inclined to the end of the second-stage boom body 332 at the front end side of the second-stage boom body 332 and projecting from the first-stage boom body 331. It is mounted for rotation. The second intermediate sheave 342 is housed between the second-stage boom body 332 and the third-stage boom body 333, and is arranged around the axis in the specific direction at the proximal end of the third-stage boom body 333. It is mounted for rotation. The third intermediate sheave 343 is inclined around the axis in the specific direction at a position inclined to the end of the four-stage boom body 334 at the end of the third-stage boom body 333 protruding from the second-stage boom body 332. It is attached to be rotatable. The fourth intermediate sheave 344 is housed between the third-stage boom body 333 and the fourth-stage boom body 334, and is arranged around the axis in the specific direction at the proximal end of the fourth-stage boom body 334. It is mounted for rotation. As shown in FIG. 1, the tip side sheave 345 is attached to the tip portion of the tip side structure 31 so as to be rotatable about the axis in the specific direction.

  The left and right undulation lines 8 are wound around the sheaves constituting the line length adjusting mechanism as follows. First, one end of the hoisting line 8 is connected to the upper swing body 2 of the boom 3 and is not displaced in the telescopic direction (in this embodiment, the distal end side of the first-stage boom body 331). The base end side portion may be, for example, the base end side structure 31.) And fixed to a fixing point 347 set to the base end side sheave 340 from the fixing point 347. By being wound around the base end side sheave 340, it is turned 180 ° upward. Hereinafter, similarly, the hoisting line 8 turns 180 ° downward by being wound around the first intermediate sheave 341 at the distal end portion of the two-stage boom body 331, and rotates at the first end portion of the three-stage boom body 333. 2 wraps around the intermediate sheave 342 and turns upward 180 °, and wraps around the third intermediate sheave 343 at the tip of the three-stage boom body 333 and turns downward 180 °, thereby turning the base of the four-stage boom body 334. It is wound around the fourth intermediate sheave 344 at the end and turned upward by 180 °, and further wound around the tip-side sheave 345 at the tip of the boom 3 and then locked to the upper spreader 23.

  According to this line length adjusting mechanism, as is apparent from FIG. 4A in particular, when the intermediate structure 33 is extended, the hoisting line 8 is fed out of the boom 3 from the tip side sheave 345 to that extent, Conversely, when the intermediate structure 33 contracts, the hoisting line 8 is taken into the boom 3 from the tip side sheave 345 by that amount. For example, when the four-stage boom body 334 is displaced to the boom tip side, that is, the boom extension side with respect to the three-stage boom body 333, the distance between the third intermediate sheave 343 and the fourth intermediate sheave 344 is reduced by that amount. The undulation line 8 having a size corresponding to the reduced amount is fed out from the tip side sheave 345. On the contrary, when the four-stage boom body 334 is displaced to the boom proximal end side, that is, the boom contraction side with respect to the three-stage boom body 333, the distance between the third intermediate sheave 343 and the fourth intermediate sheave 344 increases accordingly. The undulation line 8 having a size corresponding to the increase in the distance is taken into the boom 3 from the tip side sheave 345.

  The extending and taking-in of the hoisting line 8 accompanying the expansion and contraction of the boom 3 is a distance from the tip sheave 345 to the lower spreader 22 accompanying the extension of the boom 3 (hereinafter referred to as “an effective hoisting distance”). .) Suppressing the increase / decrease of LR, so that the boom 3 is operated in the hoisting direction when the boom 3 is extended and retracted while the hoisting winch 7 is stopped, that is, the interference between the telescopic operation and the hoisting operation. Can be suppressed.

  However, in reality, a narrow angle γ as shown in FIG. 1 exists between the boom 3 and the portion of the hoisting line 8 extending from the tip of the boom 3 to the upper spreader 23. In addition, the narrow angle γ changes according to the boom undulation angle. Therefore, even if the hoisting winch 7 is stopped, if the hoisting effective distance LR remains constant, the hoisting angle of the boom 3 is actually slightly increased as the intermediate structure 33 of the boom 3 expands and contracts. Change.

  In order to further suppress such changes, the crane according to this embodiment includes a control device as shown in FIG. This control device includes a boom angle sensor 110 that outputs a detection signal corresponding to the undulation angle α of the boom 3, that is, the angle formed by the reference axis X of the boom 3 and the horizontal line as shown in FIG. 1, and the boom length LB. A boom length sensor 120 that outputs a detection signal corresponding to FIG. 1 and a controller 100 are provided. The controller 100 includes a detection signal output from the boom angle sensor 110 and the boom length sensor 120, and an expansion / contraction command signal generated based on the operation of the expansion / contraction operation lever 130 operated to extend / contract the boom 3. The operation of the hydraulic cylinders 335 to 337 for expanding and contracting the boom 3 based on the raising and lowering command signal generated based on the operation of the raising and lowering operation lever 140 operated to raise and lower the boom 3; A signal for controlling the operation of the hoisting winch 7 is generated. The telescopic operation lever 130 and the hoisting operation lever 140 are disposed in the cab 4. In addition, the boom angle sensor 110 and the boom length sensor 120 are disposed at appropriate positions on the boom 3 and include, for example, a rotary encoder or a potentiometer.

  The controller 100 includes an angle calculation unit 101, a length calculation unit 102, an expansion / contraction operation control unit 103, a undulation operation control unit (control unit) 104, a correction unit (correction unit) 105, a memory 106, and a determination as shown in FIG. Part 107 is included. The units 101 to 107 are embodied by various programs that are read and executed by a CPU (not shown), for example.

  The angle calculation unit 101 calculates the undulation angle α of the boom 3 based on the detection signal (boom angle signal SA) output from the boom angle sensor 101, and the length calculation unit 102 detects the detection signal (output from the boom length sensor 102). The boom length LB is calculated based on the boom length signal SL). The memory 106 includes a pivot point of the boom 3 on the upper swing body 2, that is, a center point of the boom foot pin 13, and a fulcrum of the hoisting rope 9 on the upper swing body 2 side (in this embodiment, the top of the gantry 21). A straight line X connecting the vertical distance a and the horizontal distance b of the lower spreader 22) with the boom rotation fulcrum and the fulcrum of the hoisting line 8 on the tip side of the boom 3, that is, the center of the tip sheave 345. The angle β formed by ′ with respect to the reference axis X is stored.

  The determination unit 107 determines the operator's operation pattern from the presence / absence of the lever operation of the telescopic operation lever 103 and the presence / absence of the lever operation of the hoisting operation lever 104. As the operation patterns, there are an expansion / contraction operation pattern in which only the expansion / contraction operation of the boom 3 is performed, a undulation operation pattern in which only the undulation operation of the boom 3 is performed, and a composite operation pattern in which the expansion / contraction and undulation operations of the boom 3 are performed simultaneously. .

  The expansion / contraction operation control unit 103 issues an expansion / contraction operation command for the boom 3 based on the lever operation amount VT of the expansion / contraction operation lever 103. When the determination unit 107 determines that the movement operation pattern is a undulation operation pattern, the expansion / contraction operation command is issued. The expansion / contraction operation of the intermediate structure 33 is locked without the determination unit 107 determining that it is an expansion / contraction operation pattern or a composite operation pattern, and the expansion / contraction operation commands are sent to the expansion / contraction control valves 235 and 236 in the hydraulic circuit 200. 237 to input. These expansion / contraction control valves 235 to 237 are interposed between a hydraulic pump (not shown) included in the hydraulic circuit 200 and the hydraulic cylinders 335 to 337, and correspond to control signals input from the expansion / contraction operation control unit 103. By opening the valve, the hydraulic oil discharged from the hydraulic pump is supplied to the corresponding hydraulic cylinder to expand or contract the hydraulic cylinder.

  The hoisting operation control unit 104 issues a hoisting operation command for the boom 3 based on the lever operation amount VH of the hoisting operation lever 104. If the determination unit 107 determines that the hoisting operation pattern is used, the hoisting operation command is used as it is. This is input to the undulation control valve 207 in the hydraulic circuit 200. The hoisting control valve 207 is interposed between the hydraulic pump and a hydraulic motor for driving a winch drum incorporated in the hoisting winch 7, and responds to a control signal input from the hoisting operation control unit 104. By opening the valve, the hydraulic oil discharged from the hydraulic pump is supplied to the hydraulic motor, and the hydraulic motor is rotated in the winding driving direction or the feeding driving direction.

  On the other hand, when the determination unit 107 determines that the pattern is an expansion / contraction operation pattern or a composite operation pattern, the undulation operation control unit 104 inputs the undulation operation command to the correction unit 105, and the correction unit 105 corrects the undulation operation command. To do. Specifically, the correction unit 105 calculates the correction amount ΔLr using the boom hoisting angle α, the boom length LB, and the following formulas (1) to (3), and the correction amount ΔLr is set in the hoisting operation command. to add. The final undulation operation command corrected by adding the correction amount ΔLr in this way is input to the undulation control valve 207. That is, the hoisting operation control unit 104 and the correction unit 105 correspond to a winch control unit that controls the operation of the hoisting winch 7.

  The principle of correction of the undulation operation command in the composite operation pattern is as follows. First, the undulation effective distance LR, that is, the linear distance from the tip sheave 345 to the lower spreader 22 is expressed by the following equation using the distances a and b and the angle β stored in the memory 106 as described above. It can be expressed by (1).

Here, since β = tan ⁻¹ (c / LB) and L = LB / cos β, LR can be expressed as a function LR (α, LB) of the boom hoisting angle α and the boom length LB. On the other hand, when the boom 3 expands and contracts, the hoisting line 8 having a length corresponding to the expansion / contraction amount, that is, the change amount ΔLB of the boom length LB is drawn out or taken in from the tip side sheave 345. For example, as shown in FIG. Further, the fulcrum (the central point of the tip sheave 345 in this embodiment) of the hoisting line 8 on the initial boom side and the hoisting effective distance are respectively P1 and LR1, and the boom side after the boom 3 is extended from this initial state, for example. If the fulcrum of the hoisting line 8 and the hoisting effective distance are P2 and LR2, respectively, the correction amount ΔLr for keeping the boom hoisting angle α constant regardless of the extension, that is, the boom hoisting due to the expansion and contraction of the boom 3 In order to cancel the influence on the angle α, the hoisting winch 7 is unwound from the winch drum or wound around the winch drum. The length of the hoisting rope 9 shall can be expressed by the following equation.

[Equation 2]
ΔLr = LR1 + ΔLB−LR2
= LR (α ₁ , LB ₁ ) + ΔLB−LR (α ₂ , LB ₂ )
Here, when the correction amount ΔLr is a positive value, the absolute value means the winding dimension of the hoisting rope 9 by the hoisting winch 7, and conversely, when the correction amount ΔLr is a negative value (that is, the boom 3 is contracted). The absolute value of (when) means the feeding dimension of the hoisting rope 9. By adding this correction amount to the hoisting operation command, the operation amount of the hoisting operation lever 140, that is, the hoisting lever operation amount VH is accurately followed regardless of the expansion and contraction of the boom 3 (for example, the operation amount VH is 0). In this case, a final hoisting operation command (to prevent the boom 3 from moving in the hoisting direction) is generated.

  FIG. 6 shows a control operation actually performed by the controller 100.

  First, the controller 100 reads the telescopic lever operation amount VT and the hoisting lever operation amount VH (step S1), and reads the boom angle signal SA and the boom length signal SL (step S2). The boom raising / lowering angle α is calculated from SA (step S3), and the boom length LB is calculated from the boom length signal SL (step S4).

  When the absolute value of the hoisting lever operation amount VH is larger than 0 and the absolute value of the telescopic lever operation amount VT is 0 (YES in step S5), that is, when only the hoisting operation among the hoisting operation and the telescopic operation is performed. The controller 100 inputs the hoisting operation command corresponding to the hoisting lever operation amount VH to the hoisting control valve 207 as it is (that is, without correction) (step S6). As a result, the hoisting winch 7 winds or unwinds the hoisting rope 9 by an amount corresponding to the hoisting operation command, whereby the boom 3 is moved in the hoisting direction.

  On the other hand, in the case of NO in step S5, the controller 100 calculates the correction amount ΔLr using the equation (1) based on the boom undulation angle α and the boom length LB in preparation for the expansion and contraction of the boom 3 ( Step S7).

  Contrary to the above, when the absolute value of the telescopic lever operation amount VT is greater than 0 and the absolute value of the telescopic lever operation amount VT is 0 (YES in step S8), that is, out of the undulation operation and the expansion operation When only the expansion / contraction operation is performed, the controller 100 inputs an expansion / contraction operation command corresponding to the expansion / contraction lever operation amount VT to the expansion / contraction control valves 235 to 237 (step S9), and operates the hydraulic cylinders 335 to 337 to operate the boom. 3, the undulation operation command corresponding to the correction amount ΔLr, in other words, the final undulation operation command obtained by adding the correction amount ΔLr to the undulation operation command of 0, (Step S10). As described above, the final hoisting operation command is related to the expansion and contraction of the boom 3 on the assumption that the line length adjusting mechanism pays out or takes in the wire rope 8 by the tip side sheave 345 as the boom 3 expands and contracts. Therefore, the hoisting rope 9 is wound or unwound by the hoisting winch 7 based on this command, so that the boom 3 is raised and lowered. Extending and retracting the boom 3 without moving in the direction is realized.

  When the absolute value of the telescopic lever operation amount VT and the absolute value of the telescopic lever operation amount VT are both greater than 0 (YES in step S11), that is, in the case of a composite operation in which the undulation operation and the expansion operation are performed simultaneously, The controller 100 inputs a telescopic operation command corresponding to the telescopic lever operation amount VT to the telescopic control valves 235 to 237 (step S12) and operates the hydraulic cylinders 335 to 337 to expand and contract the boom 3, A final hoisting operation command obtained by adding the correction amount ΔLr to the hoisting operation command corresponding to the lever operation amount VH is input to the hoisting control valve 207 (step S13). Thus, drive control of the hoisting winch 7 that accurately follows the hoisting lever operation amount VH without being affected by the expansion and contraction of the boom 3 is realized.

  When the absolute value of the telescopic lever operation amount VT and the absolute value of the telescopic lever operation amount VT are both 0 (NO in any of steps S5, S8, and S11), the controller 100 does not output an operation command. Thereby, the stationary state of the boom 3 is maintained.

  According to the crane described above, the hoisting winch 7 winds or unwinds the hoisting rope 9 and operates the front end of the boom 3 in the hoisting direction via the hoisting line 8 connected thereto. Unlike conventional cranes in which the boom is raised and lowered with a free end, the bending moment acting on the boom 3 can be reduced, and the line length adjusting mechanism assembled to the boom 3 Even if the hoisting winch 7 is not operated when the boom 3 expands or contracts, the hoisting line 8 is fed out or taken in from the tip side sheave 345 attached to the tip of the boom according to the extension and contraction. It is possible to effectively prevent the boom 3 from moving in the undulation direction as it expands and contracts. In addition, the fact that the portion that supports the boom 3 on the distal end side is configured by a rotatable distal end sheave also leads to a reduction in the mechanical strength of the hoisting line 8 at the fulcrum.

  In addition to the line length adjusting mechanism, the crane further includes a control device that controls the operation of the hoisting winch 7 based on the expansion and contraction operation of the boom 3, and the control device includes the boom length LB and the boom length LB. Absorbs fluctuations in the effective lifting distance (distance from the tip sheave 345 to the lower spreader 22 that is the fulcrum of the lifting rope 9 on the upper swing body 2 side) due to the expansion and contraction of the boom 3 based on the lifting angle α. Therefore, since the hoisting winch 7 is operated based on the correction amount ΔLr, the effect of the expansion and contraction of the boom 3 on the hoisting operation of the boom can be more effectively suppressed. In addition, the influence of the expansion and contraction of the boom 3 on the hoisting operation is basically reduced by feeding or taking in the hoisting line 8 by the line length adjusting mechanism, so the correction amount ΔLr can be small. The necessity of moving the hoisting winch 7 at a high speed in order to eliminate the influence on the hoisting operation is reduced.

  However, in the crane according to the present invention, the control device may be omitted, and even in that case, the line length adjusting mechanism feeds or takes in the undulation line from the tip side sheave as the boom expands and contracts. As a result, it is possible to reduce the influence of the boom expansion and contraction on the undulation operation. Even when a control device is provided, the control device is not necessarily limited to the one that always performs the line length adjustment mechanism. For example, when the boom is expanded and contracted while the expansion and contraction of the boom is performed in a state where the boom is largely lying down, the above-described line length adjustment control is stopped. May be performed.

  In the present invention, the amount by which the line length adjusting mechanism pays out the undulation line as the boom extends and retracts can be set as appropriate. However, as in the above-described embodiment, when the boom 3 is extended or retracted, the hoisting line 8 is extended or taken in from the distal sheave 345 by a length corresponding to the expansion / contraction amount. The influence on the undulation operation can be reduced, and when the control device is provided, the control contents can be greatly simplified.

  Further, instead of the control device, even if the tip sheave is attached to the boom so as to move in a specific direction (for example, the boom width direction) with respect to the boom so as to absorb the fluctuation of the undulation effective distance, It is possible to eliminate or reduce the influence of the boom expansion and contraction on the undulation angle. In that case, further, an actuator for moving the tip sheave according to the tension of the hoisting line and the boom hoisting angle is provided, thereby supporting the tip sheave from the boom side with a force that does not cause the boom to fall down. Is preferred.

  In the present invention, the specific structure of the boom is not particularly limited. For example, in the above-described embodiment, the intermediate structure 33 included in the boom 3 has been shown to expand and contract by being provided with a plurality of stages of boom bodies 331 to 334. However, not only the intermediate structure 33 but also the entire boom can be expanded and contracted. It may be a thing. Further, the number of boom bodies constituting the extendable part is not particularly limited. The means for moving each boom body is not limited to the hydraulic cylinder, and an electric actuator such as an electric motor may be used. The same applies to the driving of the hoisting winch.

  In the present invention, the specific type of crane is not limited. For example, the present invention can be similarly applied to other mobile cranes such as a wheel crane and a tower crane in addition to the above-described crawler crane.

DESCRIPTION OF SYMBOLS 1 Lower traveling body 2 Upper revolving body 3 Boom 7 Hoisting winch 8 Hoisting line 9 Hoisting rope 13 Boom foot pin 21 Gantry 22 Lower spreader 33 Intermediate structure 100 Controller 104 Hoisting operation control part (constitutes winch control part)
105 Correction unit (constitutes winch control unit)
106 Memory 107 Judgment Unit 110 Boom Angle Sensor (Boom Angle Detector)
120 Boom length sensor (Boom length detector)
130 Telescopic operation lever 140 Hoisting operation lever 340 Base end side sheave (composed of a line length adjustment mechanism)
341-344 Intermediate sheave (line length adjustment mechanism)
345 Sheave on tip side

Claims (4)

A crane,
Base and
A boom that can be raised and lowered on this base and can be expanded and contracted in the longitudinal direction;
A telescopic device for expanding and contracting the boom;
A undulation line drawn from the tip of the boom;
A hoisting rope connected to the hoisting line;
A hoisting winch mounted on the base and operating the boom in the hoisting direction via the hoisting line by winding and unwinding the hoisting rope;
A telescopic operation lever operated to extend and contract the boom;
A hoisting operation lever operated to raise and lower the boom;
A line length adjusting mechanism assembled to the boom;
A control device for controlling operations of the telescopic device and the hoisting winch based on the boom telescopic operation and the hoisting operation;
With
The line length adjusting mechanism includes a plurality of sheaves including a tip side sheave attached to a tip portion of the boom, the undulation line is wound around the sheaves, and the boom extends and contracts The plurality of sheaves are arranged so that the undulation line is fed out from the tip side sheave and the undulation line is taken into the tip boom, respectively .
The controller is
Based on the operation amount of the telescopic operation lever and the hoisting operation lever, the telescopic operation pattern in which only the telescopic operation is performed among the telescopic operation and hoisting operation of the boom, and only the hoisting operation is performed among the telescopic operation and the hoisting operation. A determination unit that determines an operation pattern in which the boom is operated from a hoisting operation pattern in which the boom is operated and a composite operation pattern in which the expansion operation and the hoisting operation are performed simultaneously
A boom length detector for detecting the length of the boom;
A boom angle detector for detecting the boom undulation angle;
The boom lengths detected by the boom length detector and the boom angle detector, respectively, when the determination unit determines that the operation pattern is one of the telescopic operation pattern and the composite operation pattern. Based on the height and the undulation angle, a correction amount is calculated to absorb the fluctuation of the distance from the tip sheave to the fulcrum of the undulation rope on the base side due to the expansion and contraction of the boom, and this correction amount A winch control unit for operating the hoisting winch based on
Having a crane.   2. The crane according to claim 1, wherein the line length adjusting mechanism extends the hoisting line from the tip side sheave by a length corresponding to an extension amount of the boom as the boom extends, and the boom contracts. Accordingly, the crane takes in the hoisting line from the tip side sheave into the boom by a length corresponding to the amount of contraction. 3. The crane according to claim 2, wherein the boom includes a plurality of boom bodies arranged in a longitudinal direction of the boom, and the boom bodies extend in a telescopic direction of the boom with respect to a boom body adjacent thereto. The boom is connected so as to be relatively movable, and the boom is connected to the base and includes a proximal end portion that is not displaced in the expansion / contraction direction, and the line length adjustment mechanism is connected to the line length adjustment mechanism. The sheaves included are sheaves other than the sheaves on the front end side, and are provided rotatably at the base end side end portions and the front end side end portions of the boom bodies, respectively, and the hoisting line has a distal end at the tip of the boom. It is fixed to the base end side part, and it is spanned in order from the sheave provided on the boom body close to the base end side of the boom to each sheave, and from the tip side sheave to the outside of the boom. Issued is, crane. 4. The crane according to claim 1, wherein the control device controls the telescopic device when the operation unit determines that the operation pattern is the undulation operation pattern. 5. A crane that locks the expansion and contraction of the boom.

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