Construction machinery work equipment

Abstract

To enhance workability when a connecting pin connecting between a first member and a second member is prevented from coming off.SOLUTION: A work device of a construction machine includes a connection device 15 for connecting between a first left bracket 9 and a first right bracket 10, and a second left bracket 11 and a second right bracket 12, using a left connecting pin 13 and a right connecting pin 14. The connection device 15 includes: a left connecting pin 13 and a right connecting pin 14; a hydraulic cylinder 16; a floating link 17 mounted on the hydraulic cylinder 16; a first left link 19 for connecting between the left connecting pin 13 and the floating link 17; a first right link 20 for connecting the right connecting pin 14 and the floating link 17; a second left link 21 for connecting between the first left link 19 and the hydraulic cylinder 16; a second right link 22 for connecting between the first right link 20 and the hydraulic cylinder 16; and a pin coming-off prevention mechanism 24 for preventing the left connecting pin 13 and the right connecting pin 14 from coming off.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a working device provided in a construction machine such as a hydraulic excavator.

Background Art

[0002] A hydraulic excavator, which is representative of construction machines, is composed of a self-propelled vehicle body and a working device rotatably attached to the vehicle body. When disassembling a structure with a large ground height such as a high-rise building, a hydraulic excavator equipped with a working device for disassembly work is preferably used. This working device for disassembly work usually has a plurality of booms called a multi-boom. An arm is attached to the tip side of the uppermost boom among these booms, and a working tool such as a crusher or a grapple is attached to the tip side of the arm.

[0003] The multi-boom for disassembly work is configured to have a desired length by connecting a plurality of booms to each other. These plurality of booms are detachably connected using connection pins. That is, a left first member and a right first member provided facing each other in the left-right direction on one of the two booms connected to each other, and a left second member and a right second member provided facing each other in the left-right direction on the other boom are connected by a left connection pin and a right connection pin, respectively.

[0004] Here, a working device has been proposed that includes a coupling device for inserting and removing a left connecting pin between a left first member provided on one boom and a left second member provided on the other boom, and for inserting and removing a right connecting pin between a right first member provided on one boom and a right second member provided on the other boom. This coupling device is composed of a hydraulic cylinder, a floating link attached to the hydraulic cylinder, a left first link with one end connected to the left connecting pin and the other end connected to the floating link, a right first link with one end connected to the right connecting pin and the other end connected to the floating link, a left second link with one end connected to the middle part of the left first link and the other end connected to the hydraulic cylinder, and a right second link with one end connected to the middle part of the right first link and the other end connected to the hydraulic cylinder together with the other end of the left second link.

[0005] In the coupling device, the hydraulic cylinder extends and retracts, causing one end of the left first link and the right first link to move left and right around the connection point with the floating link. As a result, the left connecting pin and the right connecting pin are inserted into and removed from the pin insertion holes in the left first member and the right first member provided on one boom, and from the pin insertion holes in the left second member and the right second member provided on the other boom (Patent Document 1). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 5139385 [Overview of the project] [Problems that the invention aims to solve]

[0007] In the coupling device according to Reference 1, the left coupling pin is inserted through the pin insertion hole of the left first member and the pin insertion hole of the left second member, and the right coupling pin is inserted through the pin insertion hole of the right first member and the pin insertion hole of the right second member, and this state is maintained by a hydraulic cylinder.

[0008] However, when an external force is applied to the working device in the left-right direction during the operation of the hydraulic excavator, a force acts on the left connecting pin in a direction that causes it to detach from the pin insertion holes of the left first member and left second member, and a force acts on the right connecting pin in a direction that causes it to detach from the pin insertion holes of the right first member and right second member. For this reason, it is necessary to secure the left and right connecting pins to the first or second member using bolts or the like. The work of securing the left and right connecting pins with bolts or the like is done manually, which reduces work efficiency. Moreover, if the left and right connecting pins are at a high altitude, the work of securing them with bolts or the like becomes work at height, which further reduces work efficiency.

[0009] The object of the present invention is to provide a work device for construction machinery that can improve the workability when removing a connecting pin that connects a first member and a second member. [Means for solving the problem]

[0010] The present invention comprises a first front member having a left first member having a left first pin insertion hole and a right first member having a right first pin insertion hole, a second front member having a left second member having a left second pin insertion hole and a right second member having a right second pin insertion hole, and a connecting device connecting the first front member and the second front member, the connecting device comprising a left connecting pin inserted through the left first pin insertion hole and the left second pin insertion hole, a right connecting pin inserted through the right first pin insertion hole and the right second pin insertion hole, a hydraulic cylinder positioned spaced apart from the axes of the left connecting pin and the right connecting pin, and either the tube or rod of the hydraulic cylinder A working device for a construction machine comprising: a floating link mounted on the side and positioned in a floating state so as to be movable in a direction approaching or moving away from the axes of the left connecting pin and the right connecting pin; a left first link with one end connected to the left connecting pin and the other end connected to the floating link; a right first link with one end connected to the right connecting pin and the other end connected to the floating link; a left second link with one end connected to the middle part of the left first link and the other end connected to either the tube or the rod of the hydraulic cylinder; and a right second link with one end connected to the middle part of the right first link and the other end connected to either the tube or the rod of the hydraulic cylinder, wherein the The left connecting pin is inserted through the left first pin insertion hole and the left second pin insertion hole, and the right connecting pin is inserted through the right first pin insertion hole and the right second pin insertion hole. In this state, the connection between the left second link and the right second link and the hydraulic cylinder is located on the axial side of the left connecting pin and the right connecting pin, compared to the connection between the left second link and the left first link and the connection between the right second link and the right first link, and the connecting device is, When the left connecting pin is inserted through the left first pin insertion hole and the left second pin insertion hole, and the right connecting pin is inserted through the right first pin insertion hole and the right second pin insertion hole, The device is characterized by having a pin retention mechanism that restricts the movement of the left connecting pin and the right connecting pin toward the axis due to the extension operation of the hydraulic cylinder at the connection point between the left second link and the right second link and the hydraulic cylinder. [Effects of the Invention]

[0011] According to the present invention, the pin retention mechanism allows the left connecting pin to be retained in a state where it is inserted through the left first pin insertion hole and the left second pin insertion hole, and the right connecting pin to be retained in a state where it is inserted through the right first pin insertion hole and the right second pin insertion hole. This eliminates the need to use bolts or the like to retain the left and right connecting pins, thereby improving work efficiency when retaining the left and right connecting pins. [Brief explanation of the drawing]

[0012] [Figure 1] This is a front view showing a hydraulic excavator equipped with a multi-boom work device. [Figure 2] This is a front view showing the intermediate boom being attached to and detached from the lower boom. [Figure 3] This is a cross-sectional view of the coupling device according to the first embodiment, taken from the direction indicated by arrow III-III in Figure 2. [Figure 4] This is a cross-sectional view of the coupling device taken from the direction indicated by arrow IV-IV in Figure 3. [Figure 5] This is a cross-sectional view showing the lower boom and the intermediate boom separated. [Figure 6] This is a cross-sectional view showing the left and right connecting pins removed from the left and right second brackets, respectively. [Figure 7] This is a cross-sectional view showing the left connecting pin and the right connecting pin inserted into the left second bracket and the right second bracket, respectively. [Figure 8] This is a cross-sectional view showing the left connecting pin inserted through the left first pin insertion hole and the left second pin insertion hole, and the right connecting pin inserted through the right first pin insertion hole and the right second pin insertion hole. [Figure 9] This is a hydraulic circuit diagram for supplying and discharging pressurized oil to the hydraulic cylinder of a coupling device. [Figure 10] This is a cross-sectional view showing a coupling device equipped with a pin retention mechanism according to a second embodiment. [Figure 11] This is a cross-sectional view showing the state in which the left connecting pin and the right connecting pin are locked in place by the pin retention mechanism according to the second embodiment.

Best Mode for Carrying Out the Invention

[0013] Hereinafter, an embodiment of a working device of a construction machine according to the present invention will be described in detail by taking a multi-boom type working device mounted on a hydraulic excavator as an example and referring to the accompanying drawings. In this embodiment, the traveling direction of the hydraulic excavator is defined as the front-rear direction, and the direction orthogonal to the traveling direction of the hydraulic excavator is defined as the left-right direction for the description.

[0014] FIGS. 1 to 9 show a first embodiment of the present invention. In the figures, a hydraulic excavator 1 includes a crawler-type lower traveling body 2 capable of self-traveling, and an upper revolving body 3 rotatably mounted on the lower traveling body 2. A cab 3A is arranged on the front left side of the upper revolving body 3. The lower traveling body 2 and the upper revolving body 3 constitute the vehicle body of the hydraulic excavator 1, and a multi-boom type working device 4 is rotatably attached to the front side of the upper revolving body 3. The hydraulic excavator 1 is preferably used for demolishing structures with a large ground height such as high-rise buildings using the working device 4.

[0015] The multi-boom type working device 4 has a boom 5 composed of a lower boom 5A, an intermediate boom 5B, and an upper boom 5C rotatably attached to the front side of the upper revolving body 3. The lower boom 5A constitutes a first front member provided with a left first bracket 9 and a right first bracket 10, which will be described later. The intermediate boom 5B constitutes a second front member provided with a left second bracket 11 and a right second bracket 12, which will be described later. A middle arm 6 is rotatably attached to the tip side of the upper boom 5C, and an arm 7 composed of a lower arm 7A and an upper arm 7B is rotatably attached to the tip side of the middle arm 6. A crusher 8 as a working tool is rotatably attached to the tip side of the upper arm 7B. <管理>

[0016] When attaching the intermediate boom 5B to the lower boom 5A of the boom 5, for example, as shown in FIG. 2, with the lower boom 5A held horizontally with respect to the ground, the intermediate boom 5B is lifted using a hydraulic crane 100 or the like. Then, with the intermediate boom 5B disposed on the tip side of the lower boom 5A, the lower boom 5A and the intermediate boom 5B are connected using the left connecting pin 13, the right connecting pin 14, etc., which will be described later. Specifically, the left first bracket 9 provided at the tip of the lower boom 5A and the left second bracket 11 provided at the base end of the intermediate boom 5B are connected via the left connecting pin 13, and the right first bracket 10 provided at the tip of the lower boom 5A and the right second bracket 12 provided at the base end of the intermediate boom 5B are connected via the right connecting pin 14.

[0017] The left first bracket 9 as the left first member is provided on the left side of the tip of the lower boom 5A. The left first bracket 9 is formed in a bifurcated shape by a left inner first bracket 9A and a left outer first bracket 9B facing each other in the left-right direction at a certain interval. These left inner first bracket 9A and left outer first bracket 9B are formed using a steel plate or the like and are fixed to the tip of the lower boom 5A using means such as welding.

[0018] The left second bracket 11, which will be described later, is disposed between the left inner first bracket 9A and the left outer first bracket 9B. At both ends in the length direction of the left inner first bracket 9A and the left outer first bracket 9B, left first pin insertion holes 9C penetrating in the left-right direction are respectively formed, and the left connecting pin 13 is inserted into these a total of four left first pin insertion holes 9C so as to be removable.

[0019] The right first bracket 10 as the right first member is provided on the right side of the tip of the lower boom 5A. The right first bracket 10 is formed in a bifurcated shape by a right inner first bracket 10A and a right outer first bracket 10B facing each other in the left-right direction at a certain interval. These right inner first bracket 10A and right outer first bracket 10B are formed using a steel plate or the like and are fixed to the tip of the lower boom 5A using means such as welding.

[0020] A right second bracket 12, described later, is positioned between the right inner first bracket 10A and the right outer first bracket 10B. Right first pin insertion holes 10C, which penetrate in the left-right direction, are drilled at both ends of the right inner first bracket 10A and the right outer first bracket 10B in the longitudinal direction, and right connecting pins 14 are inserted into these four right first pin insertion holes 10C in a removable manner.

[0021] The left first pin insertion hole 9C, drilled in the left inner first bracket 9A and left outer first bracket 9B of the left first bracket 9, and the right first pin insertion hole 10C, drilled in the right inner first bracket 10A and right outer first bracket 10B of the right first bracket 10, are located on the same axis AA.

[0022] The left second bracket 11, as the left second member, is provided on the left side of the base end of the intermediate boom 5B. The left second bracket 11 is formed using steel plate or the like and is fixed to the base end of the intermediate boom 5B by means of welding or other means. The left second bracket 11 is positioned between the left inner first bracket 9A and the left outer first bracket 9B of the left first bracket 9, and faces these left inner first bracket 9A and left outer first bracket 9B in the left-right direction. The left second bracket 11 has a left second pin insertion hole 11A that penetrates in the left-right direction at a position corresponding to the left first pin insertion hole 9C of the left first bracket 9.

[0023] The right second bracket 12, as the right second member, is provided on the right side of the base end of the intermediate boom 5B. The right second bracket 12 is formed using steel plate or the like and is fixed to the base end of the intermediate boom 5B by means of welding or other means. The right second bracket 12 is positioned between the right inner first bracket 10A and the right outer first bracket 10B of the right first bracket 10, and faces these right inner first bracket 10A and right outer first bracket 10B in the left-right direction. The right second bracket 12 has a right second pin insertion hole 12A that penetrates in the left-right direction at a position corresponding to the right first pin insertion hole 10C of the right first bracket 10.

[0024] The left second pin insertion hole 11A of the left second bracket 11 aligns with the left first pin insertion hole 9C of the left first bracket 9 on the same axis AA, and the right second pin insertion hole 12A of the right second bracket 12 aligns with the right first pin insertion hole 10C of the right first bracket 10 on the same axis AA.

[0025] Two left connecting pins 13 are provided spaced apart along the length of the left first bracket 9, connecting the left first bracket 9 and the left second bracket 11. The left connecting pins 13 are formed in a cylindrical shape extending in the left-right direction and are removably inserted into the left first pin insertion hole 9C of the left first bracket 9 and the left second pin insertion hole 11A of the left second bracket 11. Therefore, the axis of the left connecting pin 13 lies on the same axis AA as the left first pin insertion hole 9C of the left first bracket 9. A link mounting portion 13A is provided on the base end of the left connecting pin 13, and one end 19A of the left first link 19, which will be described later, is rotatably attached to the link mounting portion 13A.

[0026] Two right connecting pins 14 are provided on the right first bracket 10, spaced apart along its length, connecting the right first bracket 10 and the right second bracket 12. The right connecting pins 14 are formed in a cylindrical shape extending in the left-right direction and are removably inserted into the right first pin insertion hole 10C of the right first bracket 10 and the right second pin insertion hole 12A of the right second bracket 12. Therefore, the axis of the right connecting pin 14 aligns with the same axis AA as the right first pin insertion hole 10C of the right first bracket 10. A link mounting portion 14A is provided on the base end of the right connecting pin 14, and one end 20A of the right first link 20, which will be described later, is rotatably attached to the link mounting portion 14A.

[0027] Thus, the left connecting pins 13 and right connecting pins 14 are provided in two sets (a total of four pins) spaced apart along the length of the right first bracket 10. The two left connecting pins 13 are inserted into the left first pin insertion hole 9C of the left first bracket 9 and the left second pin insertion hole 11A of the left second bracket 11, respectively. The two right connecting pins 14 are inserted into the right first pin insertion hole 10C of the right first bracket 10 and the right second pin insertion hole 12A of the right second bracket 12, respectively. The left first bracket 9 and the left second bracket 11 are connected via the two left connecting pins 13, and the right first bracket 10 and the right second bracket 12 are connected via the two right connecting pins 14, thereby connecting the intermediate boom 5B to the lower boom 5A.

[0028] Next, the coupling device 15, which is positioned between the left first bracket 9 and the right first bracket 10, will be described. The coupling device 15 inserts and removes the left coupling pin 13 into the left first pin insertion hole 9C and the left second pin insertion hole 11A, and inserts and removes the right coupling pin 14 into the right first pin insertion hole 10C and the right second pin insertion hole 12A.

[0029] The coupling device 15 is provided in two sets, spaced apart in the longitudinal direction of the left first bracket 9 and the right first bracket 10. These two sets of coupling devices 15 have the same configuration and include a left coupling pin 13, a right coupling pin 14, a hydraulic cylinder 16 (described later), a floating link 17, a left first link 19, a right first link 20, a left second link 21, a right second link 22, and a pin retention mechanism 24.

[0030] The hydraulic cylinder 16 is positioned at a distance from the axis AA of the left connecting pin 13 and the right connecting pin 14. The hydraulic cylinder 16 consists of a tube 16A, a piston 16B (see Figure 9), and a rod 16C whose base end is fixed to the piston 16B and whose tip end protrudes from the tube 16A. The hydraulic cylinder 16 extends and retracts the rod 16C when pressurized oil is supplied and discharged from a hydraulic source, causing the left connecting pin 13 and the right connecting pin 14 to move axially via the left first link 19, the right first link 20, the left second link 21, the right second link 22, etc.

[0031] The floating link 17 is attached to the hydraulic cylinder 16. The floating link 17 is formed by two triangular plates facing each other across the tube 16A of the hydraulic cylinder 16, and is attached to the tube 16A. The floating link 17 is not attached to either the left first bracket 9 or the right first bracket 10, and is positioned in a floating state that allows it to move toward or away from the axis AA of the left connecting pin 13 and the right connecting pin 14.

[0032] The length L of the floating link 17 in the left-right direction is set to be slightly smaller than the distance between the left inner first bracket 9A and the right inner first bracket 10A. As a result, a small gap is formed between the left end of the floating link 17 and the left inner first bracket 9A, and between the right end of the floating link 17 and the right inner first bracket 10A. Therefore, the floating link 17 can move between the left inner first bracket 9A and the right inner first bracket 10A in accordance with the extension and contraction of the hydraulic cylinder 16. The bottom side of the hydraulic cylinder 16 (tube 16A) is rotatably attached to the middle portion of the floating link 17 in the left-right direction via a pin 18. In addition, the base ends of the left first link 19 and the right first link 20, which will be described later, are rotatably connected to the floating link 17.

[0033] The left first link 19 connects the left connecting pin 13 and the floating link 17. The left first link 19 is formed by two plates facing each other with the floating link 17 in between. One end 19A in the longitudinal direction of the left first link 19 is connected to the link mounting portion 13A of the left connecting pin 13 via pin 19B. The other end 19C in the longitudinal direction of the left first link 19 is connected to the floating link 17 via pin 19D.

[0034] The right first link 20 connects the right connecting pin 14 and the floating link 17. The right first link 20 is formed by two plates facing each other with the floating link 17 in between. One end 20A in the longitudinal direction of the right first link 20 is connected to the link mounting portion 14A of the right connecting pin 14 via pin 20B. The other end 20C in the longitudinal direction of the right first link 20 is connected to the floating link 17 via pin 20D.

[0035] The left second link 21 connects the middle section of the left first link 19 in the longitudinal direction to the rod 16C of the hydraulic cylinder 16. The left second link 21 is formed by two plates facing each other with the rod 16C of the hydraulic cylinder 16 in between, and transmits the extension and retraction force of the hydraulic cylinder 16 to the left first link 19. One end 21A of the left second link 21 in the longitudinal direction is connected to the middle section of the left first link 19 via a pin 21B, and the other end 21C of the left second link 21 in the longitudinal direction is connected to the tip of the rod 16C of the hydraulic cylinder 16 via a pin 16D.

[0036] The right second link 22 connects the middle section of the right first link 20 in the longitudinal direction to the rod 16C of the hydraulic cylinder 16. The right second link 22 is formed by two plates facing each other with the rod 16C of the hydraulic cylinder 16 in between, and transmits the extension and retraction force of the hydraulic cylinder 16 to the right first link 20. One end 22A of the right second link 22 in the longitudinal direction is connected to the middle section of the right first link 20 via a pin 22B, and the other end 22C of the right second link 22 in the longitudinal direction is connected to the tip of the rod 16C of the hydraulic cylinder 16 via a pin 16D.

[0037] In this way, the other end 21C of the left second link 21, the other end 22C of the right second link 22, and the tip of the rod 16C of the hydraulic cylinder 16 are rotatably connected via a common pin 16D. The extension and retraction force of the hydraulic cylinder 16 is transmitted to the left first link 19 via the left second link 21 and to the right first link 20 via the right second link 22. As a result, the left first link 19 rotates left and right with the connection point (pin 19D) with the floating link 17 as the pivot point, and the right first link 20 rotates left and right with the connection point (pin 20D) with the floating link 17 as the pivot point.

[0038] As shown in Figures 6 to 8, when the hydraulic cylinder 16 is extended, the left connecting pin 13 connected to one end 19A of the left first link 19 is inserted through the left first pin insertion hole 9C of the left first bracket 9 and the left second pin insertion hole 11A of the left second bracket 11. Also, the right connecting pin 14 connected to one end 20A of the right first link 20 is inserted through the right first pin insertion hole 10C of the right first bracket 10 and the right second pin insertion hole 12A of the right second bracket 12. As a result, the left first bracket 9 and the left second bracket 11 can be connected via the left connecting pin 13, and the right first bracket 10 and the right second bracket 12 can be connected via the right connecting pin 14.

[0039] On the other hand, when the hydraulic cylinder 16 is retracted, the left connecting pin 13 is removed from the left second pin insertion hole 11A of the left second bracket 11, and the right connecting pin 14 is removed from the right second pin insertion hole 12A of the right second bracket 12. This allows the left second bracket 11 to be separated from the left first bracket 9, and the right second bracket 12 to be separated from the right first bracket 10.

[0040] In this way, the coupling device 15 is displaced by the extension and retraction of the hydraulic cylinder 16 to a coupled position (position in Figure 3) in which the left coupling pin 13 is inserted through the left first pin insertion hole 9C and the left second pin insertion hole 11A, and the right coupling pin 14 is inserted through the right first pin insertion hole 10C and the right second pin insertion hole 12A, and to a detached position (position in Figure 6) in which the left coupling pin 13 is detached from the left second pin insertion hole 11A, and the right coupling pin 14 is detached from the right second pin insertion hole 12A.

[0041] When the hydraulic cylinder 16 retracts and the left connecting pin 13 is withdrawn from the left second pin insertion hole 11A, the left connecting pin 13 remains inserted only through the left first pin insertion hole 9C of the left inner first bracket 9A. Also, when the hydraulic cylinder 16 retracts and the right connecting pin 14 is withdrawn from the right second pin insertion hole 12A, the right connecting pin 14 remains inserted only through the right first pin insertion hole 10C of the right inner first bracket 10A. As a result, the connecting device 15 is cantilevered by the left connecting pin 13 and the right connecting pin 14 and held between the left inner first bracket 9A and the right inner first bracket 10A.

[0042] The left inner first bracket 9A of the left first bracket 9 and the right inner first bracket 10A of the right first bracket 10 are each provided with a rotation-preventing member 23. The rotation-preventing member 23 consists of a rectangular prism-shaped block and is fixed to the inner surface of the left inner first bracket 9A and the inner surface of the right inner first bracket 10A, specifically the portion corresponding to the floating link 17, using means such as welding. The rotation-preventing member 23 is sandwiched between the two plates constituting the floating link 17 with a small gap between them, thereby restricting the rotation of the connecting device 15 around the left connecting pin 13 and the right connecting pin 14.

[0043] Next, the pin retention mechanism 24 used in the first embodiment will be described. The pin retention mechanism 24 is provided on each of the two sets of connecting devices 15 and is composed of a pin 25 and an engaging member 26, which will be described later. The pin retention mechanism 24 prevents the left connecting pin 13, which is inserted through the left first pin insertion hole 9C of the left first bracket 9 and the left second pin insertion hole 11A of the left second bracket 11, from being removed by restricting the extension movement of the hydraulic cylinder 16, and also prevents the right connecting pin 14, which is inserted through the right first pin insertion hole 10C of the right first bracket 10 and the right second pin insertion hole 12A of the right second bracket 12 from being removed.

[0044] Pins 25 are provided on each of the two plate bodies that make up the right second link 22. Pins 25 have a cylindrical shaft and are fixed to the other end 22C of the right second link 22, which is connected to the rod 16C of the hydraulic cylinder 16 via pin 16D. Pins 25 are positioned on the other end 22C of the right second link 22 and protrude away from the hydraulic cylinder 16.

[0045] The engaging members 26 are provided on each of the left second link 21, which is composed of two plate bodies. The engaging members 26 are made of plate bodies having the same thickness as the left second link 21, for example, and are fixed to the outer peripheral edge of the other end 21C of the left second link 21, which is connected to the rod 16C of the hydraulic cylinder 16 via a pin 16D. The engaging members 26 protrude in a direction perpendicular to the longitudinal direction of the left second link 21, and a recessed hook 26A that engages with the pin 25 is formed on the protruding end side of the engaging member 26.

[0046] The engaging member 26 approaches the pin 25 as the coupling device 15 is displaced from the disconnected position shown in Figure 6 to the connected position shown in Figure 3 by the extension of the hydraulic cylinder 16. Then, after the left connecting pin 13 is inserted through the left first pin insertion hole 9C and the left second pin insertion hole 11A, and the right connecting pin 14 is inserted through the right first pin insertion hole 10C and the right second pin insertion hole 12A, the engaging member 26 engages with the pin 25 at the connected position shown in Figure 3 as the hydraulic cylinder 16 extends further.

[0047] Here, we focus on the displacement of pins 16D, 21B, and 22B accompanying the extension movement of the hydraulic cylinder 16. As shown in Figures 6 and 7, when the left connecting pin 13 is not inserted through the left first pin insertion hole 9C of the left outer first bracket 9B, and the right connecting pin 14 is not inserted through the right first pin insertion hole 10C of the right outer first bracket 10B, the centers of pins 16D, 21B, and 22B are arranged in an isosceles triangle shape, with pins 21B and 22B closer to axis AA than pin 16D. As shown in Figure 8, when the left connecting pin 13 is inserted through the left first pin insertion hole 9C of the left outer first bracket 9B, and the right connecting pin 14 is inserted through the right first pin insertion hole 10C of the right outer first bracket 10B, the centers of pins 16D, 21B, and 22B are arranged on a straight line.

[0048] In the coupling position of the coupling device 15 shown in Figure 3, when the engaging member 26 of the pin retention mechanism 24 is engaged with the pin 25, the centers of pins 16D, 21B, and 22B are arranged in an isosceles triangle shape, with pin 16D being closer to axis AA than pins 21B and 22B. In this state, when the lower boom 5A and the intermediate boom 5B are connected by the coupling device 15, the connection portion (pin 16D) between the left second link 21 and the right second link 22 and the hydraulic cylinder 16 is located closer to axis AA of the left connecting pin 13 and the right connecting pin 14 than the connection portion (pin 21B) between the left second link 21 and the left first link 19, and the connection portion (pin 22B) between the right second link 22 and the right first link 20.

[0049] When the centers of pins 16D, 21B, and 22B are arranged in an isosceles triangle shape as shown in Figure 3, if a force acts on the left connecting pin 13 in the direction away from the left first pin insertion hole 9C and the left second pin insertion hole 11A (direction F indicated by arrow), an extension force acts on the rod 16C of the hydraulic cylinder 16. Similarly, if a force acts on the right connecting pin 14 in the direction away from the right first pin insertion hole 10C and the right second pin insertion hole 12A (direction F indicated by arrow), an extension force acts on the rod 16C of the hydraulic cylinder 16.

[0050] However, at the connection position of the coupling device 15, the engaging member 26 of the pin retention mechanism 24 engages with the pin 25, thereby preventing further extension of the hydraulic cylinder 16 (rod 16C). In this way, the pin retention mechanism 24 restricts the connection portion (pin 16D) between the left second link 21 and the right second link 22 and the hydraulic cylinder 16 from moving toward the axis AA side of the left connecting pin 13 and the right connecting pin 14 due to the extension of the hydraulic cylinder 16. As a result, the left connecting pin 13 is retained from the left first pin insertion hole 9C and the left second pin insertion hole 11A, and the right connecting pin 14 is retained from the right first pin insertion hole 10C and the right second pin insertion hole 12A.

[0051] Next, the hydraulic circuit that drives the hydraulic cylinder 16 of the coupling device 15 will be described with reference to Figure 9. In Figure 9, the hydraulic source, consisting of the main hydraulic pump 27 and tank 28, and the hydraulic cylinder 16 are connected via oil passages 29 and 30. Oil passage 29 is connected to the rod-side oil chamber 16E of the hydraulic cylinder 16, and oil passage 30 is connected to the bottom-side oil chamber 16F of the hydraulic cylinder 16.

[0052] A control valve 31 is provided in the oil passages 29 and 30, located between the hydraulic power source and the hydraulic cylinder 16. The control valve 31 is formed, for example, by a 6-port, 3-position directional control valve, and is switched from a neutral position (a) to a switching position (b) or a switching position (c) in accordance with the pilot pressure supplied to the hydraulic pilot sections 31A and 31B. In addition, a pilot-operated check valve 39, described later, is provided in the oil passage 30, located between the hydraulic cylinder 16 and the control valve 31.

[0053] The control valve 31 is switched to position (b) when pilot pressure is supplied to the hydraulic pilot unit 31A. As a result, pressurized oil from the hydraulic pump 27 is supplied to the bottom oil chamber 16F of the hydraulic cylinder 16, and the rod 16C of the hydraulic cylinder 16 extends. The control valve 31 is switched to position (c) when pilot pressure is supplied to the hydraulic pilot unit 31B. As a result, pressurized oil from the hydraulic pump 27 is supplied to the rod-side oil chamber 16E of the hydraulic cylinder 16, and the rod 16C of the hydraulic cylinder 16 retracts.

[0054] The hydraulic pilot section 31A of the control valve 31 and the pilot pump 32 are connected via a pilot oil passage 33. A switching valve 34 is provided in the pilot oil passage 33, located between the hydraulic pilot section 31A and the pilot pump 32. The switching valve 34 is formed by a 3-port, 2-position solenoid valve and is switched from the shut-off position (d) to the supply position (e) when a pilot signal is supplied to the solenoid pilot section 34A.

[0055] The hydraulic pilot section 31B of the control valve 31 and the pilot pump 32 are connected via a pilot oil passage 35. A switching valve 36 is provided in the pilot oil passage 35, located between the hydraulic pilot section 31B and the pilot pump 32. The switching valve 36 is formed by a 3-port, 2-position solenoid valve and is switched from the shut-off position (f) to the supply position (g) when a pilot signal is supplied to the solenoid pilot section 36A. In addition, an on-off valve 41, described later, is provided in the pilot oil passage 35, located between the hydraulic pilot section 31B and the switching valve 36.

[0056] A connecting pin insertion switch 37 is connected to the electromagnetic pilot section 34A of the switching valve 34. The connecting pin insertion switch 37 is installed, for example, in the cab 3A and is operated ON / OFF by an operator. When the connecting pin insertion switch 37 is operated ON, the switching valve 34 is switched to the supply position (e), and pilot pressure from the pilot pump 32 is supplied to the hydraulic pilot section 31A of the control valve 31. Consequently, the control valve 31 moves to the switching position (b), and the rod 16C of the hydraulic cylinder 16 extends. As a result, the left connecting pin 13 is inserted through the left first pin insertion hole 9C and the left second pin insertion hole 11A, and the right connecting pin 14 is inserted through the right first pin insertion hole 10C and the right second pin insertion hole 12A, and the connecting device 15 moves to the connecting position shown in Figure 3.

[0057] A coupling pin removal switch 38 is connected to the electromagnetic pilot section 36A of the switching valve 36. The coupling pin removal switch 38 is installed, for example, in the cab 3A and is operated ON / OFF by an operator. When the coupling pin removal switch 38 is operated ON, the switching valve 36 is switched to the supply position (g), and pilot pressure from the pilot pump 32 is supplied to the hydraulic pilot section 31B of the control valve 31. Consequently, the control valve 31 moves to the switching position (c), and the rod 16C of the hydraulic cylinder 16 retracts. As a result, the left coupling pin 13 is removed from the left second pin insertion hole 11A, and the right coupling pin 14 is removed from the right second pin insertion hole 12A, and the coupling device 15 moves to the disconnection position shown in Figure 6.

[0058] The pilot-operated check valve 39 is located in the oil passage 30 between the hydraulic cylinder 16 and the control valve 31. A branch pilot oil passage 40, which branches off from the pilot oil passage 35, is connected to the pilot-operated check valve 39. When pilot pressure is not supplied through the branch pilot oil passage 40, the pilot-operated check valve 39 allows pressurized oil to be supplied to the bottom oil chamber 16F of the hydraulic cylinder 16, and prevents pressurized oil from being discharged from the bottom oil chamber 16F. On the other hand, when pilot pressure is supplied through the branch pilot oil passage 40, the pilot-operated check valve 39 allows the supply and discharge of pressurized oil to and from the bottom oil chamber 16F of the hydraulic cylinder 16.

[0059] Therefore, when the coupling pin removal switch 38 is turned ON to move the coupling device 15 to the disconnected position, and the switching valve 36 is in the supply position (g), pilot pressure is supplied to the hydraulic pilot section 31B of the control valve 31, a portion of this pilot pressure is supplied to the pilot-operated check valve 39 through the branched pilot oil passage 40. As a result, the pressurized oil in the bottom oil chamber 16F of the hydraulic cylinder 16 is discharged to the tank 28 through the oil passage 30, and the rod 16C of the hydraulic cylinder 16 retracts.

[0060] Thus, the pilot-operated check valve 39 allows the supply of pressurized oil to the bottom oil chamber 16F of the hydraulic cylinder 16 when moving the coupling device 15 to the coupling position, and restricts the supply and discharge of pressurized oil to the bottom oil chamber 16F of the hydraulic cylinder 16 when moving the coupling device 15 to the disconnected position. On the other hand, when pilot pressure (pilot signal) is supplied to the hydraulic pilot section 31B of the control valve 31 to move the coupling device 15 to the disconnected position, the pilot-operated check valve 39 allows the supply and discharge of pressurized oil to the bottom oil chamber 16F of the hydraulic cylinder 16. In other words, unless the coupling pin removal switch 38 is operated, the rod 16C of the hydraulic cylinder 16 will not retract, and the configuration prevents the coupling device 15 from unintentionally moving to the disconnected position.

[0061] The on-off valve 41, which functions as a signal switch, is located between the hydraulic pilot section 31B of the control valve 31 and the switching valve 36 and is provided in the pilot oil passage 35. The on-off valve 41 is formed by a 3-port, 2-position solenoid valve and is switched from the closed position (h) to the open position (j) when a pilot signal is supplied to the solenoid pilot section 41A. A calculator 42 is connected to the solenoid pilot section 41A of the on-off valve 41, and an angle sensor 43, which functions as a rotation angle detector, is connected to the calculator 42.

[0062] The angle sensor 43 is installed, for example, on a connecting shaft (not shown) that rotatably connects the upper slewing body 3 and the lower boom 5A. It detects the rotation angle of the lower boom 5A relative to the upper slewing body 3 and outputs a signal corresponding to this rotation angle to the arithmetic unit 42. The arithmetic unit 42 compares the detected rotation angle of the lower boom 5A with a preset predetermined value. When the rotation angle of the lower boom 5A is less than the predetermined value, for example, as shown in Figure 2, when the lower boom 5A is extended horizontally to the ground, the arithmetic unit 41 outputs a pilot signal to the electromagnetic pilot unit 41A of the on-off valve 41. In this way, when the rotation angle of the lower boom 5A relative to the upper slewing body 3 detected by the angle sensor 43 is less than the predetermined value, the on-off valve 41 supplies a pilot signal to the hydraulic pilot unit 31B of the control valve 31 to move the connecting device 15 to the disconnected position.

[0063] As a result, the on-off valve 41 switches from the closed position (h) to the open position (j), and when the coupling pin removal switch 38 is turned ON, pilot pressure from the pilot pump 32 is supplied to the hydraulic pilot section 31B of the control valve 31 through the pilot oil passage 35. In addition, a portion of this pilot pressure is supplied to the pilot-operated check valve 39 through the branched pilot oil passage 40. In this way, the coupling device 15 can be moved to the detached position only when the ground clearance of the upper surface of the lower boom 5A is, for example, within a range that does not constitute work at height.

[0064] The working device 4 of the hydraulic excavator 1 according to this embodiment has the coupling device 15 described above, and the operation of connecting the intermediate boom 5B to the lower boom 5A of the working device 4 will be described.

[0065] First, as shown in Figure 2, the base end of the lower boom 5A is attached to the upper slewing body 3 of the hydraulic excavator 1, and the lower boom 5A is held in a position horizontal to the ground. In this state, the intermediate boom 5B is lifted using the hydraulic crane 100, and as shown in Figure 5, the base end of the intermediate boom 5B is positioned towards the tip of the lower boom 5A.

[0066] At this time, as shown in Figure 6, with the hydraulic cylinder 16 retracted, the coupling device 15 has its left coupling pin 13 inserted through the left first pin insertion hole 9C of the left inner first bracket 9A, and its right coupling pin 14 inserted through the right first pin insertion hole 10C of the right inner first bracket 10A. As a result, the coupling device 15 is held between the left inner first bracket 9A and the right inner first bracket 10A via the left coupling pin 13 and the right coupling pin 14.

[0067] In this state, the left second bracket 11 provided on the intermediate boom 5B is inserted between the left inner first bracket 9A and the left outer first bracket 9B provided on the lower boom 5A, and the right second bracket 12 provided on the intermediate boom 5B is inserted between the right inner first bracket 10A and the right outer first bracket 10B provided on the lower boom 5A. Then, the left second pin insertion hole 11A of the left second bracket 11 is aligned with the left first pin insertion hole 9C of the left first bracket 9 on the same axis AA, and the right second pin insertion hole 12A of the right second bracket 12 is aligned with the right first pin insertion hole 10C of the right first bracket 10 on the same axis AA.

[0068] In this state, by turning on the connecting pin insertion switch 37, the switching valve 34 switches to the supply position (e), and pilot pressure from the pilot pump 32 is supplied to the hydraulic pilot section 31A of the control valve 31. As a result, the control valve 31 switches to the switching position (b), and pressurized oil from the hydraulic pump 27 is supplied to the bottom oil chamber 16F of the hydraulic cylinder 16, causing the rod 16C of the hydraulic cylinder 16 to extend. The force of the hydraulic cylinder 16 is transmitted to the left first link 20 via the left second link 21, and also to the right first link 20 via the right second link 22. Therefore, as shown in Figures 7 and 8, one end 19A of the left first link 19 rotates toward the left first bracket 9 with the pin 19D as the pivot point, and one end 20A of the right first link 20 rotates toward the right first bracket 10 with the pin 20D as the pivot point.

[0069] As a result, the left connecting pin 13 is inserted through the left first pin insertion hole 9C of the left first bracket 9 and the left second pin insertion hole 11A of the left second bracket 11, and the right connecting pin 14 is inserted through the right first pin insertion hole 10C of the right first bracket 10 and the right second pin insertion hole 12A of the right second bracket 12. In this way, the left first bracket 9 and the left second bracket 11 can be connected via the left connecting pin 13, and the right first bracket 10 and the right second bracket 12 can be connected via the right connecting pin 14. At this time, the pin 25 and the engaging member 26 that constitute the pin retention mechanism 24 move closer to each other as the left second link 21 and the right second link 22 are displaced.

[0070] As the hydraulic cylinder 16 extends, the left connecting pin 13 is inserted into the left first pin insertion hole 9C and the left second pin insertion hole 11A, and the right connecting pin 14 is inserted into the right first pin insertion hole 10C and the right second pin insertion hole 12A. After this, the hydraulic cylinder 16 is further extended. As a result, the coupling device 15 is displaced to the coupling position shown in Figure 3, and the hook 26A of the engaging member 26 provided on the left second link 21 engages with the pin 25 provided on the right second link 22. In this way, by displacing the coupling device 15 to the coupling position shown in Figure 3 and assembling the work device 4 with the lower boom 5A and intermediate boom 5B connected, demolition work and the like can be performed using the hydraulic excavator 1 equipped with the work device 4.

[0071] During operation of the hydraulic excavator 1, an external force is applied to the working device 4 in the left-right direction, causing a force to act on the left connecting pin 13 in the direction of separation from the left first pin insertion hole 9C and the left second pin insertion hole 11A (direction F indicated by arrow). Similarly, a force acts on the right connecting pin 14 in the direction of separation from the right first pin insertion hole 10C and the right second pin insertion hole 12A (direction F indicated by arrow).

[0072] Here, when the coupling device 15 is displaced to the coupling position shown in Figure 3, the centers of pins 16D, 21B, and 22B are arranged in an isosceles triangle shape, with pin 16D closer to axis AA than pins 21B and 22B. Therefore, when a force in the direction of arrow F acts on the left coupling pin 13, one end 21A of the left second link 21 is pressed against the left first link 19, causing the other end 21C of the left second link 21 to be displaced in a direction that extends the rod 16C of the hydraulic cylinder 16. Similarly, when a force in the direction of arrow F acts on the right coupling pin 14, one end 22A of the right second link 22 is pressed against the right first link 20, causing the other end 22C of the right second link 22 to be displaced in a direction that extends the rod 16C of the hydraulic cylinder 16.

[0073] However, when the coupling device 15 is displaced to the coupling position shown in Figure 3, the hook 26A of the engaging member 26 provided on the left second link 21 engages with the pin 25 provided on the right second link 22. This prevents further extension of the hydraulic cylinder 16 by the engagement between the engaging member 26 and the pin 25. As a result, the left connecting pin 13 can be locked in place between the left first bracket 9 and the left second bracket 11, and the right connecting pin 14 can be locked in place between the right first bracket 10 and the right second bracket 12.

[0074] Therefore, there is no need to remove the left connecting pin 13 from the left first bracket 9 and the left second bracket 11 using a bolt or the like, and there is no need to remove the right connecting pin 14 from the right first bracket 10 and the right second bracket 12 using a bolt or the like. As a result, the work of removing the left connecting pin 13 and the right connecting pin 14 using a bolt or the like can be eliminated, and high-altitude work by the worker can also be eliminated. Accordingly, according to this embodiment, the workability when removing the left connecting pin 13 and the right connecting pin 14 that connect the lower boom 5A and the intermediate boom 5B can be improved.

[0075] Next, we will explain the process of separating the intermediate boom 5B from the lower boom 5A of the working device 4.

[0076] First, as shown in Figure 2, the lower boom 5A, to which the intermediate boom 5B is connected, is rotated relative to the upper slewing body 3 so that it is horizontal to the ground, and the height of the upper surface of the lower boom 5A from the ground is maintained at a position that does not involve working at height. Then, the intermediate boom 5B is lifted using the hydraulic crane 100.

[0077] In this state, by turning on the connecting pin removal switch 38, the switching valve 36 switches to the supply position (g), and pilot pressure from the pilot pump 32 is led to the pilot oil passage 35. At this time, the calculator 42 compares the rotation angle of the lower boom 5A detected by the angle sensor 43 with a preset predetermined value, and when the rotation angle of the lower boom 5A is less than the predetermined value, for example, when the lower boom 5A is in a horizontal position relative to the ground as shown in Figure 2, it outputs a pilot signal to the on-off valve 41. As a result, the on-off valve 41 switches to the open position (j), and the pilot pressure is supplied to the hydraulic pilot section 31B of the control valve 31 through the pilot oil passage 35. In addition, a portion of the pilot pressure is supplied to the pilot-operated check valve 39 through the branch pilot oil passage 40.

[0078] As a result, pressurized oil from the hydraulic pump 27 is supplied to the rod-side oil chamber 16E of the hydraulic cylinder 16, and the pressurized oil in the bottom-side oil chamber 16F is discharged to the tank 28, causing the rod 16C of the hydraulic cylinder 16 to retract. This causes one end 19A of the left first link 19 to rotate towards the right connecting pin 14 with the pin 19D as a pivot point, and one end 20A of the right first link 20 to rotate towards the left connecting pin 13 with the pin 20D as a pivot point. As a result, the coupling device 15 is displaced to the detachment position shown in Figure 6, the left connecting pin 13 is removed from the left second pin insertion hole 11A of the left second bracket 11, and the right connecting pin 14 is removed from the right second pin insertion hole 12A of the right second bracket 12. As a result, the intermediate boom 5B can be detached from the lower boom 5A of the working device 4.

[0079] In this embodiment, an on-off valve 41 is provided in the pilot oil passage 35. The on-off valve 41 supplies a pilot signal to the control valve 31 (hydraulic pilot unit 31B) to move the coupling device 15 to the detachment position when the rotation angle of the lower boom 5A detected by the angle sensor 43 is less than a predetermined value. Therefore, the coupling device 15 can be moved to the detachment position only when the ground clearance of the upper surface of the lower boom 5A is within a range that does not constitute high-altitude work. In other words, if the rotation angle of the lower boom 5A exceeds a predetermined value and the ground clearance of the upper surface of the lower boom 5A falls within the range of high-altitude work, the coupling device 15 can be prevented from moving to the detachment position. As a result, the safety of the detachment operation between the lower boom 5A and the intermediate boom 5B can be enhanced.

[0080] Furthermore, in this embodiment, a pilot-operated check valve 39 is provided in the oil passage 30, and the pilot-operated check valve 39 allows the supply and discharge of pressurized oil to and from the bottom oil chamber 16F of the hydraulic cylinder 16 when pilot pressure is supplied to the control valve 31 by operating the coupling pin removal switch 38. Therefore, unless the coupling pin removal switch 38 is operated, the retraction operation of the hydraulic cylinder 16 can be prohibited, and the coupling device 15 can be reliably prevented from moving unintentionally to the disconnected position.

[0081] Next, Figures 10 and 11 show a second embodiment of the present invention. The characteristic of this embodiment is that the pin retention mechanism is configured with stoppers that contact the left second link and the right second link to limit the extension movement of the hydraulic cylinder. In this embodiment, the same reference numerals are used for the same components as in the first embodiment, and their descriptions are omitted.

[0082] The stopper 44, which acts as a pin removal mechanism, is provided between the left first bracket 9 and the right first bracket 10, and is positioned on the opposite side from the coupling device 15, straddling the axis AA of the left connecting pin 13 and the right connecting pin 14. The stopper 44 restricts the extension movement of the hydraulic cylinder 16 by contacting the left second link 21 and the right second link 22 of the coupling device 15.

[0083] The stopper 44 consists of a base plate 44A spanning between the left inner first bracket 9A and the right inner first bracket 10A, and a contact plate 44B protruding from the center of the base plate 44A in the left-right direction. The contact plate 44B extends from the base plate 44A toward the rod 16C of the hydraulic cylinder 16, and when the coupling device 15 is displaced to the coupling position shown in Figure 11, the other end 21C of the left second link 21 and the other end 22C of the right second link 22 come into contact with the contact plate 44B, thereby preventing further extension of the hydraulic cylinder 16 (rod 16C).

[0084] The coupling device 15 according to the second embodiment has a stopper 44 as described above, and by extending the hydraulic cylinder 16, the left coupling pin 13 is inserted through the left first pin insertion hole 9C and the left second pin insertion hole 11A, and the right coupling pin 14 is inserted through the right first pin insertion hole 10C and the right second pin insertion hole 12A. Then, as shown in Figure 10, after the centers of pins 16D, 21B and 22B are aligned in a straight line, the hydraulic cylinder 16 is further extended.

[0085] As a result, the coupling device 15 is displaced to the coupling position shown in Figure 11, and the centers of pins 16D, 21B, and 22B are arranged in an isosceles triangle shape, with pin 16D closer to axis AA than pins 21B and 22B. In this state, the other end 21C of the left second link 21 and the other end 22C of the right second link 22, which are connected to the rod 16C of the hydraulic cylinder 16, come into contact with the contact plate 44B of the stopper 44. This prevents the hydraulic cylinder 16 from extending any further, which can be prevented by the stopper 44. As a result, the left coupling pin 13 can be locked in place between the left first bracket 9 and the left second bracket 11, and the right coupling pin 14 can be locked in place between the right first bracket 10 and the right second bracket 12.

[0086] Thus, the working device 4 according to the embodiment comprises a first front member having a left first bracket 9 with a left first pin insertion hole 9C and a right first bracket 10 with a right first pin insertion hole 10C, a second front member having a left second bracket 11 with a left second pin insertion hole 11A and a right second bracket 12 with a right second pin insertion hole 12A, and a connecting device 15 that connects the first front member and the second front member, the connecting device 15 having a left connecting pin 1 inserted through the left first pin insertion hole 9C and the left second pin insertion hole 11A 3, a right connecting pin 14 inserted through the right first pin insertion hole 10C and the right second pin insertion hole 12A, a hydraulic cylinder 16 positioned spaced apart from the axes of the left connecting pin 13 and the right connecting pin 14, a floating link 17 attached to the tube 16A of the hydraulic cylinder 16 and positioned in a floating state that can move in a direction toward or away from the axes of the left connecting pin 13 and the right connecting pin 14, a left first link 19 with one end 19A connected to the left connecting pin 13 and the other end 19C connected to the floating link 17, and one end 20A connected to the right connecting pin 14 and the other end 20C In a construction machine work device comprising a right first link 20 connected to a floating link 17, a left second link 21 with one end 21A connected to the middle part of the left first link 19 and the other end 21C connected to the rod 16C of a hydraulic cylinder 16, and a right second link 22 with one end 22A connected to the middle part of the right first link 20 and the other end 22C connected to the hydraulic cylinder 16 together with the other end 21C of the left second link 21, when the first front member and the second front member are connected by a connecting device 15, the left second link 21 and the right second link 2 The connection point (pin 16D) between the left second link 21 and the left first link 19 (pin 21B) and the connection point (pin 22B) between the right second link 22 and the right first link 20 is located on the axis AA side of the left connecting pin 13 and the right connecting pin 14, and the connecting device 15 is characterized by having a pin retention mechanism 24 that restricts the movement of the left connecting pin 13 and the right connecting pin 14 toward the axis AA side due to the extension operation of the hydraulic cylinder 16 at the connection point (pin 16D) between the left second link 21 and the right second link 22 and the hydraulic cylinder 16.

[0087] In this configuration, the first front member and the second front member are connected by a connecting device 15, and the connecting portion (pin 16D) between the left second link 21 and the right second link 22 and the hydraulic cylinder 16 is located on the axis AA side of the left connecting pin 13 and the right connecting pin 14, compared to the connecting portion (pin 21B) between the left second link 21 and the left first link 19, and the connecting portion (pin 22B) between the right second link 22 and the right first link 20. In this state, the pin retention mechanism 24 restricts the connecting portion (pin 16D) from moving on the axis AA side of the left connecting pin 13 and the right connecting pin 14 due to the extension operation of the hydraulic cylinder 16. Therefore, the left connecting pin 13 can be secured by inserting it through the left first pin insertion hole 9C and the left second pin insertion hole 11A, and the right connecting pin 14 can be secured by inserting it through the right first pin insertion hole 10C and the right second pin insertion hole 12A. This eliminates the need to secure the left connecting pin 13 and the right connecting pin 14 with bolts or the like, improving the workability when securing the left connecting pin 13 and the right connecting pin 14.

[0088] In this embodiment, the pin retention mechanism 24 comprises a pin 25 provided on one of the left second link 21 and the right second link 22, and an engaging member 26 provided on the other of the left second link 21 and the right second link 22, which engages with the pin 25 to restrict the extension movement of the hydraulic cylinder 16 after the left connecting pin 13 is inserted into the left first pin insertion hole 9C and the left second pin insertion hole 11A, and the right connecting pin 14 is inserted into the right first pin insertion hole 10C and the right second pin insertion hole 12A, as a result of the extension movement of the hydraulic cylinder 16. With this configuration, since the displacement of the left second link 21 and the right second link 22 is prohibited when the engaging member 26 is engaged with the pin 25, further extension movement of the hydraulic cylinder 16 can be restricted, and the left connecting pin 13 and the right connecting pin 14 can be retained.

[0089] In this embodiment, the pin retention mechanism is provided between the left first bracket 9 and the right first bracket 10. The left connecting pin 13 is inserted into the left first pin insertion hole 9C and the left second pin insertion hole 11A as the hydraulic cylinder 16 extends, and the right connecting pin 14 is inserted into the right first pin insertion hole 10C and the right second pin insertion hole 12A. After this, a stopper 44 contacts the left second link 21 and the right second link 22 to restrict the extension movement of the hydraulic cylinder 16. With this configuration, when the left second link 21 and the right second link 22 are in contact with the stopper 44, the extension movement of the hydraulic cylinder 16 can be restricted, and the left connecting pin 13 and the right connecting pin 14 can be prevented from being removed.

[0090] In this embodiment, the coupling device 15 is displaced by the extension and retraction of the hydraulic cylinder 16 to a coupled position in which the left coupling pin 13 is inserted through the left first pin insertion hole 9C and the left second pin insertion hole 11A, and the right coupling pin 14 is inserted through the right first pin insertion hole 10C and the right second pin insertion hole 12A, and to a disconnected position in which the left coupling pin 13 is detached from the left first pin insertion hole 9C or the left second pin insertion hole 11A, and the right coupling pin 14 is detached from the right first pin insertion hole 10C or the right second pin insertion hole 12A, and a pilot is provided in the oil passage connecting the hydraulic cylinder 16 and the hydraulic power source. A control valve 31 controls the direction of pressurized oil supplied to the hydraulic cylinder 16 in response to a signal, and a pilot-operated check valve 39 is provided that allows the supply and discharge of pressurized oil to the hydraulic cylinder 16 when the coupling device 15 is moved to the coupling position, and restricts the supply and discharge of pressurized oil to the hydraulic cylinder 16 when the coupling device 15 is moved to the disconnected position. The pilot-operated check valve 39 allows the supply and discharge of pressurized oil to the hydraulic cylinder 16 when a pilot signal is supplied to the control valve 31 to move the coupling device 15 to the disconnected position. With this configuration, unless an operation is performed to supply a pilot signal to the control valve 31 to move the coupling device 15 to the disconnected position, the retraction operation of the hydraulic cylinder 16 can be prohibited, and the coupling device 15 can be reliably prevented from moving to the disconnected position unintentionally.

[0091] In this embodiment, the left first bracket 9 and the right first bracket 10 are provided at the tip of the lower boom 5A, which is rotatably attached to the upper slewing body 3 of a self-propelled hydraulic excavator 1, and the left second bracket 11 and the right second bracket 12 are provided at the base end of the intermediate boom 5B, which is attached to the tip of the lower boom 5A. An angle sensor 43 is provided to detect the rotation angle of the lower boom 5A relative to the upper slewing body 3, and an on-off valve 41 is provided to switch the supply and cut off of a pilot signal to the control valve 31. The on-off valve 41 supplies a pilot signal to the control valve 31 to move the coupling device 15 to the detached position when the rotation angle of the lower boom 5A relative to the upper slewing body 3, as detected by the angle sensor 43, is less than a predetermined value. With this configuration, the coupling device 15 can be moved to the detached position only when the rotation angle of the lower boom 5A relative to the upper slewing body 3 is less than a predetermined value and the ground clearance of the upper surface of the lower boom 5A is, for example, within a range that does not constitute high-altitude work. As a result, the safety of the separation operation between the lower boom 5A and the intermediate boom 5B can be improved.

[0092] In the first embodiment, a pin retention mechanism 24 is formed by a pin 25 provided on the right second link 22 and an engaging member 26 provided on the left second link 21, and the extension movement of the hydraulic cylinder 16 is restricted by the engaging member 26 with the pin 25. In the second embodiment, a stopper 44 is provided between the left first bracket 9 and the right first bracket 10, and the extension movement of the hydraulic cylinder 16 is restricted by the left second link 21 and the right second link 22 contacting the stopper 44. However, the present invention is not limited to these, and for example, the pin retention mechanism may be formed by the stroke end on the extension side of the hydraulic cylinder 16. That is, the hydraulic cylinder 16 may be configured to reach its stroke end when it is extended, with the left connecting pin 13 inserted through the left first pin insertion hole 9C of the left first bracket 9 and the left second pin insertion hole 11A of the left second bracket 11, and the right connecting pin 14 inserted through the right first pin insertion hole 10C of the right first bracket 10 and the right second pin insertion hole 12A of the right second bracket 12.

[0093] Furthermore, in this embodiment, the left first bracket 9 is made up of two plates, a left inner first bracket 9A and a left outer first bracket 9B, and the right first bracket 10 is made up of two plates, a right inner first bracket 10A and a right outer first bracket 10B. However, the present invention is not limited to this, and for example, the left first bracket and the right first bracket may each be made up of a single plate.

[0094] Furthermore, in the embodiment, an example is shown in which a left connecting pin 13, a right connecting pin 14, and a connecting device 15 are used in the connecting portion between the lower boom 5A and the intermediate boom 5B that constitute the boom 5 of the work device 4. However, the present invention is not limited to this, and may also be used, for example, in the connecting portion between the intermediate boom 5B and the upper boom 5C, or in the connecting portion between the lower arm 7A and the upper arm 7B that constitute the arm 7.

[0095] Furthermore, the embodiment illustrates a case where the lower boom 5A is provided with a left first bracket 9 and a right first bracket 10, and the intermediate boom 5B is provided with a left second bracket 11 and a right second bracket 12. However, the present invention is not limited to this, and for example, the lower boom 5A may be provided with a left second bracket 11 and a right second bracket 12, and the intermediate boom 5B may be provided with a left first bracket 9 and a right first bracket 10. [Explanation of symbols]

[0096] 3. Upper rotating body (vehicle body) 4. Working equipment 5A Lower boom (first front member) 5B Intermediate boom (second front member) 9. Left first bracket (left first component) 9C Left first pin insertion hole 10 Right first bracket (right first member) 10C Right first pin insertion hole 11. Left second bracket (left second component) 12 Right second bracket (right second component) 13 Left connecting pin 14 Right connecting pin 15 Coupling device 16 Hydraulic Cylinders 17 Floating Links 19 Left 1st link 20 Right 1st link 21 Left 2nd link 22 Right 2nd link 24 Pin retention mechanism 25 pins 26 Engaging member 27. Hydraulic pump (hydraulic source) 28 Tank (hydraulic source) 29,30 Oil passage 31 Control valve 39. Pilot-operated check valve (check valve) 41. On / off valve (signal changeover) 43. Angle sensor (rotation angle detector) 44. Stopper (pin retention mechanism)

Claims

1. The device comprises a first front member having a left first member with a left first pin insertion hole and a right first member with a right first pin insertion hole, a second front member having a left second member with a left second pin insertion hole and a right second member with a right second pin insertion hole, and a connecting device connecting the first front member and the second front member. The coupling device includes a left coupling pin inserted through the left first pin insertion hole and the left second pin insertion hole, A right connecting pin is inserted through the right first pin insertion hole and the right second pin insertion hole, A hydraulic cylinder positioned at a location spaced apart from the axes of the left connecting pin and the right connecting pin, A floating link is attached to either the tube or the rod of the hydraulic cylinder and is positioned in a floating state so as to be movable in a direction toward or toward the axes of the left connecting pin and the right connecting pin, A left first link, one end of which is connected to the left connecting pin and the other end of which is connected to the floating link, A right first link, one end of which is connected to the right connecting pin and the other end of which is connected to the floating link, A left second link, one end of which is connected to the middle section of the left first link and the other end of which is connected to either the tube or the rod of the hydraulic cylinder, A construction machine working device comprising a right second link, one end of which is connected to the middle part of the right first link and the other end of which is connected to either the tube or the rod of the hydraulic cylinder, When the left connecting pin is inserted through the left first pin insertion hole and the left second pin insertion hole, and the right connecting pin is inserted through the right first pin insertion hole and the right second pin insertion hole, the connection portion between the left second link and the right second link and the hydraulic cylinder is located on the axial side of the left connecting pin and the right connecting pin than the connection portion between the left second link and the left first link and the connection portion between the right second link and the right first link. The coupling device is characterized by having a pin retention mechanism that restricts the axial movement of the left coupling pin and the right coupling pin due to the extension operation of the hydraulic cylinder at the connection between the left second link and the right second link and the hydraulic cylinder, when the left coupling pin is inserted through the left first pin insertion hole and the left second pin insertion hole, and the right coupling pin is inserted through the right first pin insertion hole and the right second pin insertion hole.

2. A first front member having a left first member having a left first pin insertion hole and a right first member having a right first pin insertion hole; a second front member having a left second member having a left second pin insertion hole and a right second member having a right second pin insertion hole; and a connecting device connecting the first front member and the second front member, The coupling device includes a left coupling pin inserted through the left first pin insertion hole and the left second pin insertion hole, A right connecting pin is inserted through the right first pin insertion hole and the right second pin insertion hole, A hydraulic cylinder positioned at a location spaced apart from the axes of the left connecting pin and the right connecting pin, A floating link is attached to either the tube or the rod of the hydraulic cylinder and is positioned in a floating state so as to be movable in a direction toward or toward the axes of the left connecting pin and the right connecting pin, A left first link, one end of which is connected to the left connecting pin and the other end of which is connected to the floating link, A right first link, one end of which is connected to the right connecting pin and the other end of which is connected to the floating link, A left second link, one end of which is connected to the middle section of the left first link and the other end of which is connected to either the tube or the rod of the hydraulic cylinder, A construction machine working device comprising a right second link, one end of which is connected to the middle part of the right first link and the other end of which is connected to either the tube or the rod of the hydraulic cylinder, When the first front member and the second front member are connected by the connecting device, the connection portion between the left second link and the right second link and the hydraulic cylinder is located on the axial side of the left connecting pin and the right connecting pin, compared to the connection portion between the left second link and the left first link and the connection portion between the right second link and the right first link. The coupling device includes a pin retention mechanism that restricts the axial movement of the left and right connecting pins due to the extension operation of the hydraulic cylinder at the connection point between the left second link and the right second link and the hydraulic cylinder. The pin retention mechanism is characterized by being the stroke end of the hydraulic cylinder, and is a working device for construction machinery.

3. A first front member having a left first member having a left first pin insertion hole and a right first member having a right first pin insertion hole; a second front member having a left second member having a left second pin insertion hole and a right second member having a right second pin insertion hole; and a connecting device connecting the first front member and the second front member. The coupling device includes a left coupling pin inserted through the left first pin insertion hole and the left second pin insertion hole, A right connecting pin is inserted through the right first pin insertion hole and the right second pin insertion hole, A hydraulic cylinder positioned at a location spaced apart from the axes of the left connecting pin and the right connecting pin, A floating link is attached to either the tube or the rod of the hydraulic cylinder and is positioned in a floating state so as to be movable in a direction toward or toward the axes of the left connecting pin and the right connecting pin, A left first link, one end of which is connected to the left connecting pin and the other end of which is connected to the floating link, A right first link, one end of which is connected to the right connecting pin and the other end of which is connected to the floating link, A left second link, one end of which is connected to the middle section of the left first link and the other end of which is connected to either the tube or the rod of the hydraulic cylinder, A construction machine working device comprising a right second link, one end of which is connected to the middle part of the right first link and the other end of which is connected to either the tube or the rod of the hydraulic cylinder, When the first front member and the second front member are connected by the connecting device, the connection portion between the left second link and the right second link and the hydraulic cylinder is located on the axial side of the left connecting pin and the right connecting pin, compared to the connection portion between the left second link and the left first link and the connection portion between the right second link and the right first link. The coupling device includes a pin retention mechanism that restricts the axial movement of the left and right connecting pins due to the extension operation of the hydraulic cylinder at the connection point between the left second link and the right second link and the hydraulic cylinder. The pin retention mechanism includes a pin provided on one of the left second link and the right second link, A working device for a construction machine, characterized by comprising an engaging member provided on the other side of the left second link and the right second link, wherein the left connecting pin is inserted into the left first pin insertion hole and the left second pin insertion hole by the extension operation of the hydraulic cylinder, and the right connecting pin is inserted into the right first pin insertion hole and the right second pin insertion hole, and the engaging member engages with the pins to restrict the extension operation of the hydraulic cylinder.

4. A first front member having a left first member having a left first pin insertion hole and a right first member having a right first pin insertion hole; a second front member having a left second member having a left second pin insertion hole and a right second member having a right second pin insertion hole; and a connecting device connecting the first front member and the second front member, The coupling device includes a left coupling pin inserted through the left first pin insertion hole and the left second pin insertion hole, A right connecting pin is inserted through the right first pin insertion hole and the right second pin insertion hole, A hydraulic cylinder positioned at a location spaced apart from the axes of the left connecting pin and the right connecting pin, A floating link is attached to either the tube or the rod of the hydraulic cylinder and is positioned in a floating state so as to be movable in a direction toward or toward the axes of the left connecting pin and the right connecting pin, A left first link, one end of which is connected to the left connecting pin and the other end of which is connected to the floating link, A right first link, one end of which is connected to the right connecting pin and the other end of which is connected to the floating link, A left second link, one end of which is connected to the middle section of the left first link and the other end of which is connected to either the tube or the rod of the hydraulic cylinder, A construction machine working device comprising a right second link, one end of which is connected to the middle part of the right first link and the other end of which is connected to either the tube or the rod of the hydraulic cylinder, When the first front member and the second front member are connected by the connecting device, the connection portion between the left second link and the right second link and the hydraulic cylinder is located on the axial side of the left connecting pin and the right connecting pin, compared to the connection portion between the left second link and the left first link and the connection portion between the right second link and the right first link. The coupling device includes a pin retention mechanism that restricts the axial movement of the left and right connecting pins due to the extension operation of the hydraulic cylinder at the connection point between the left second link and the right second link and the hydraulic cylinder. The pin retention mechanism is provided between the left first member and the right first member, and is configured with a stopper that, after the left connecting pin is inserted into the left first pin insertion hole and the left second pin insertion hole and the right connecting pin is inserted into the right first pin insertion hole and the right second pin insertion hole by the extension operation of the hydraulic cylinder, abuts against the left second link and the right second link to restrict the extension operation of the hydraulic cylinder.

5. A first front member having a left first member having a left first pin insertion hole and a right first member having a right first pin insertion hole; a second front member having a left second member having a left second pin insertion hole and a right second member having a right second pin insertion hole; and a connecting device connecting the first front member and the second front member, The coupling device includes a left coupling pin inserted through the left first pin insertion hole and the left second pin insertion hole, A right connecting pin is inserted through the right first pin insertion hole and the right second pin insertion hole, A hydraulic cylinder positioned at a location spaced apart from the axes of the left connecting pin and the right connecting pin, A floating link is attached to either the tube or the rod of the hydraulic cylinder and is positioned in a floating state so as to be movable in a direction toward or toward the axes of the left connecting pin and the right connecting pin, A left first link, one end of which is connected to the left connecting pin and the other end of which is connected to the floating link, A right first link, one end of which is connected to the right connecting pin and the other end of which is connected to the floating link, A left second link, one end of which is connected to the middle section of the left first link and the other end of which is connected to either the tube or the rod of the hydraulic cylinder, A construction machine working device comprising a right second link, one end of which is connected to the middle part of the right first link and the other end of which is connected to either the tube or the rod of the hydraulic cylinder, When the first front member and the second front member are connected by the connecting device, the connection portion between the left second link and the right second link and the hydraulic cylinder is located on the axial side of the left connecting pin and the right connecting pin, compared to the connection portion between the left second link and the left first link and the connection portion between the right second link and the right first link. The coupling device includes a pin retention mechanism that restricts the axial movement of the left and right connecting pins due to the extension operation of the hydraulic cylinder at the connection point between the left second link and the right second link and the hydraulic cylinder. The coupling device is displaced by the extension and retraction of the hydraulic cylinder to a coupling position in which the left coupling pin is inserted through the left first pin insertion hole and the left second pin insertion hole, and the right coupling pin is inserted through the right first pin insertion hole and the right second pin insertion hole, and to a detached position in which the left coupling pin is detached from the left first pin insertion hole or the left second pin insertion hole, and the right coupling pin is detached from the right first pin insertion hole or the right second pin insertion hole. The oil passage connecting the hydraulic cylinder and the hydraulic power source is provided with a control valve that controls the direction of pressurized oil supplied to the hydraulic cylinder in response to a pilot signal, and a check valve that allows the supply and discharge of pressurized oil to and from the hydraulic cylinder when the coupling device is moved to the coupling position, and restricts the supply and discharge of pressurized oil to and from the hydraulic cylinder when the coupling device is moved to the disconnection position. The work device of a construction machine is characterized in that the check valve allows the supply and discharge of pressurized oil to the hydraulic cylinder when a pilot signal is supplied to the control valve in order to move the coupling device to the disconnected position.

6. The left first member and the right first member are provided at the tip of the first front member which is rotatably attached to a self-propelled vehicle body. The left second member and the right second member are configured to be provided at the base end of the second front member, which is attached to the tip of the first front member. A rotation angle detector is provided to detect the rotation angle of the first front member relative to the vehicle body. A signal switch is provided to switch the supply and interruption of a pilot signal to the control valve. The work device for a construction machine according to claim 5, characterized in that the signal switch supplies a pilot signal to the control valve to move the coupling device to the disconnected position when the rotation angle of the first front member relative to the vehicle body detected by the rotation angle detector is less than a predetermined value.

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