JP2009091757A - Grapple device of construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grapple device of a construction machine enhanced in durability and stabilized in operation by preventing a hydraulic cylinder for operating grapple arms from being overheated. <P>SOLUTION: The grapple device comprises a plurality of the grapple arms 6, 7 so rotatably attached to the end of a boom 4 as to be opposed to each other. A hydraulic cylinder 15 for rotating the grapple arms 6, 7 in the holding direction during extension and rotating the grapple arms 6, 7 in the opening direction during retraction is provided. A bypass oil path 29 allowing a first oil path 25 for extending the hydraulic cylinder 15 to communicate with a second oil path 26 for retracting the hydraulic cylinder 15 is formed near the hydraulic cylinder 15. A relief valve 30 is installed in the bypass oil path 29. The relief valve 30 makes hydraulic oil flow from the second oil path 26 to the first oil path 25 when the pressure of the hydraulic oil supplied into the second oil path 26 reaches a predetermined value. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a grapple device for a construction machine that is attached to the tip of a boom of a construction machine, such as a power shovel, and that grabs timber, rocks, or the like or squeezes a tree to break it.

  In general, a grapple device of a construction machine is configured such that two or four grapple arms are rotatably coupled to a mounting bracket provided at the tip of a boom so that each grapple arm is opened and closed by a hydraulic cylinder. I have to. In this case, the hydraulic cylinder is configured so that the grapple arm can be closed to grasp a timber or rock, or can be crushed by pinching the tree during an extension operation that exerts a large force.

By the way, the conventional grapple device is operated by supplying hydraulic oil to the hydraulic cylinder by a hydraulic pump installed in the main body of the construction machine, and excess hydraulic oil is provided with a relief valve provided in the vicinity of the hydraulic pump. It was returned to the oil tank through which it was cooled and purified. In this case, the hydraulic oil is recirculated only in the vicinity of the hydraulic pump, and the hydraulic oil in the hydraulic cylinder portion is not returned to the oil tank. For this reason, if the hydraulic cylinder that operates the grapple arm is frequently expanded and contracted due to continuation of work, etc., the hydraulic cylinder is heated by the hydraulic oil, resulting in a decrease in durability or an unstable operation. It was a thing.
JP-A-8-319639

  An object of the present invention is to obtain a grapple device for a construction machine that improves durability and stabilizes operation by preventing heating of a hydraulic cylinder that operates a grapple arm.

The present invention is configured as follows to achieve the above object. That is, the invention according to claim 1 is provided with a plurality of grapple arms facing each other at the tip of the boom so as to be pivotable, and the grapple arm is pivoted in the clamping direction during the extension operation, and the grapple during the shortening operation. A bypass oil passage provided with a hydraulic cylinder that rotates the arm in the opening direction, and a first oil passage that extends the hydraulic cylinder and a second oil passage that shortens the hydraulic cylinder communicate with each other in the vicinity of the hydraulic cylinder The relief valve is provided in the bypass oil passage, and the relief valve is configured to move from the second oil passage to the first oil passage when the pressure of the hydraulic oil supplied to the second oil passage reaches a predetermined value. The hydraulic oil is allowed to flow.
According to a second aspect of the present invention, an auxiliary machine is attached to the case of the hydraulic cylinder, and a bypass oil passage and a relief valve are provided in the auxiliary machine.

  In the invention according to claim 1 of the present application, when the hydraulic oil is supplied to the first oil passage, the hydraulic cylinder extends and the grapple arm is closed to hold the object. When the hydraulic oil is supplied to the second oil passage, the hydraulic cylinder is shortened and the grapple arm is opened to release the object. In this state, when the pressure of the hydraulic oil in the second oil passage reaches a predetermined value, the relief valve is opened and the hydraulic oil flows from the second oil passage to the first oil passage, and the oil passes through the first oil passage. It will be returned to the tank. As a result, the hydraulic oil returned to the oil tank is cooled in the oil tank to prevent the hydraulic cylinder from being heated, and the hydraulic oil returned to the oil tank is filtered by the filter. Can be purified.

  In the invention according to claim 2, since the bypass oil passage and the relief valve are provided in the auxiliary machine attached to the case of the hydraulic cylinder, the size can be reduced and the existing hydraulic cylinder can be easily improved.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing an open / close state of a grapple device according to the present invention, FIG. 2 is a hydraulic circuit showing an extension operation state of a hydraulic cylinder, and FIG. 3 is a hydraulic circuit showing a shortening operation state of the hydraulic cylinder.

  In FIG. 1, reference numeral 1 denotes a grapple device, which includes a mounting bracket 2, a pair of upper and lower grapple arms 6 and 7, and a hydraulic cylinder 15 that opens and closes the grapple arms 6 and 7 as main components. The mounting bracket 2 is connected to the tip of the boom 4 through a horizontal and widthwise support shaft 3 so as to be pivotable up and down, and is centered on the support shaft 3 by a hydraulic bracket cylinder 5 attached to the boom side. The rotation is controlled up and down.

  A pair of upper and lower grapple arms 6 and 7 having a fork shape are attached to the mounting bracket 2 so as to be rotatable. That is, the first fulcrum pin P1 and the second fulcrum pin P2 are arranged in parallel with the support shaft 3 on the upper and lower portions of the front portion of the mounting bracket 2, and are rotatably mounted. The operation brackets 6a and 7a are fixed to P2, the connection members 6b and 7b are fixed to the operation brackets 6a and 7a by extending in the width direction, and a plurality of clamping claws 6c and 7c are arranged in parallel with the connection members 6b and 7b. And protruding and fixed toward the front (left side in FIG. 1).

  A connecting rod 10 is rotatably connected to the upper and lower operating brackets 6a and 7a. That is, the upper end of the connecting rod 10 is rotatably connected to the upper operating bracket 6a via the third fulcrum pin P3 disposed in front of the first fulcrum pin P1, and the lower end of the connecting rod 10 is connected to the second fulcrum pin P2. Is pivotally connected to the lower working bracket 7a via a fourth fulcrum pin P4 arranged at the rear of the actuator. Thereby, the upper and lower grapple arms 6 and 7 are interlocked in the opening / closing (contact / separation) direction.

   And the hydraulic cylinder 15 which rotates the upper grapple arm 6 is attached. That is, the lower end (base portion) of the cylinder case 16 is rotatably connected to the lower portion of the mounting bracket 2 via the fifth fulcrum pin P5, and the upper end (tip end) of the cylinder rod 17 connected to the piston 18 (FIG. 2). ) Is rotatably connected to the rear end portion of the upper working bracket 6a via a sixth fulcrum pin P6 disposed behind the first fulcrum pin P1. As a result, when the hydraulic cylinder 15 is shortened, the upper and lower grapple arms 6 and 7 are opened as shown by the solid lines in FIG. 1, and when the hydraulic cylinder 15 is extended, the upper and lower grapple arms are opened. 6 and 7 are closed as shown by the phantom lines in FIG. 1 to grab the wood W or the like.

  The hydraulic cylinder 15 is expanded and contracted by supplying hydraulic oil from the hydraulic circuit 20 shown in FIGS. 2 and 3, reference numeral 20 denotes a hydraulic circuit, and a hydraulic pump 21, a control valve 22 with a relief valve, a manual switching valve 23, and an oil tank 24 are installed on the main body side of the construction machine. Switching operation is performed by a foot pedal provided in the cab. The oil tank 24 is equipped with a cooling device and a filter (not shown) so that the working oil in the oil tank 24 is cooled and purified.

  The first oil passage 25 and the second oil passage 26 that are switched by the manual switching valve 23 are extended to the hydraulic cylinder 15 along the boom 4, and the end of the first oil passage 25 is connected to the first variable throttle valve 27. To the base of the cylinder case 16 and the end of the second oil passage 26 is connected to the tip of the cylinder case 16 (on the cylinder rod 17 side) via the second variable throttle valve 28.

  A bypass oil passage 29 connects the first oil passage 25 and the second oil passage 26 located immediately upstream (on the manual switching valve 23 side) of the first variable throttle valve 27 and the second variable throttle valve 28; A relief valve 30 is attached in the middle of the bypass oil passage 29. The relief valve 30 opens when the pressure of the hydraulic oil supplied to the second oil passage 26 reaches a predetermined value, that is, when the pressure becomes slightly higher than the opening operating pressure of the grapple arm 6. The hydraulic oil in the second oil passage 26 is caused to flow toward the first oil passage 25.

  As shown in FIG. 1, the first and second variable throttle valves 27 and 28, the bypass oil passage 29, and the relief valve 30 are assembled in an auxiliary machine 31 attached to the outer wall of the cylinder case 16, and the hydraulic cylinder 15 and It is integrated.

  According to the embodiment, when the discharge path of the hydraulic pump 21 is connected to the first oil path 25 side by the manual switching valve 23, the hydraulic oil is supplied to the first oil path 25 and the first variable as shown in FIG. It flows into the base side of the cylinder case 16 through the throttle valve 27, and the hydraulic cylinder 15 is extended. Then, as shown by the phantom line in FIG. 1, the cylinder rod 17 protrudes from the cylinder case 16 to operate the grapple arms 6 and 7 in the closing direction, and the object, that is, the wood W is clamped with a predetermined force. become. After sandwiching the wood W with a predetermined force, excess hydraulic oil discharged from the hydraulic pump 21 passes through a relief valve provided in the control valve 22 and is returned to the oil tank 24.

  Further, when the discharge path of the hydraulic pump 21 is connected to the second oil path 26 side by the manual switching valve 23, as shown in FIG. 3, the hydraulic oil passes through the second oil path 26 and the second variable throttle valve 28. Then, it flows into the tip end side of the cylinder case 16 and the hydraulic cylinder 15 is shortened. In this case, as shown by the solid line in FIG. 1, the cylinder rod 17 enters the cylinder case 16 to operate the grapple arms 6 and 7 in the opening direction to release the object, that is, the wood W. Become.

  In this state, when the pressure of the hydraulic oil in the second oil passage 26 reaches a predetermined value, the relief valve 30 on the hydraulic cylinder 15 side is opened, and the operation supplied to the second oil passage 26 as shown in FIG. Oil flows in the direction of the first oil passage 25 through the bypass oil passage 29. As a result, the heated hydraulic oil flowing out from the base side of the cylinder case 16 is returned to the oil tank 24 by the hydraulic oil flowing from the second oil passage 26 to the first oil passage 25. The returned hydraulic oil is cooled in the oil tank 24 and filtered by a filter provided in the oil tank 24. As a result, heating of the hydraulic cylinder 15 is prevented.

  The first and second variable throttle valves 27, 28, the bypass oil passage 29, and the relief valve 30 are integrated into the auxiliary machine 31 attached to the outer wall of the cylinder case 16 and integrated with the hydraulic cylinder 15. Therefore, it is possible to reduce the size and easily improve the existing hydraulic cylinder.

It is a side view which shows the open / close state of the grapple device by this invention. It is a hydraulic circuit which shows the expansion operation state of a hydraulic cylinder. It is a hydraulic circuit which shows the shortening operation state of a hydraulic cylinder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Grapple apparatus 2 Mounting bracket 3 Support shaft 4 Boom 5 Bracket cylinder 6 Grapple arm 6a Actuation bracket 6b Connection member 6c Holding claw 7 Grapple arm 7a Actuation bracket 7b Connection member 7c Holding claw 10 Connection rod 15 Hydraulic cylinder 16 Cylinder case 17 Cylinder case 17 18 Piston 20 Hydraulic circuit 21 Hydraulic pump 22 Control valve 23 Manual switching valve 24 Oil tank 25 First oil passage 26 First variable throttle valve 27 Second oil passage 28 Second variable throttle valve 29 Bypass oil passage 30 Relief valve 31 Auxiliary machine P1 to P6 First fulcrum pin to sixth fulcrum pin

Claims (2)

  A plurality of grapple arms (6, 7) are provided at the front end of the boom (4) so as to be opposed to each other so as to be rotatable, and the grapple arms (6, 7) are rotated in the clamping direction during extension operation, and shortened. A hydraulic cylinder (15) for rotating the grapple arm (6, 7) in the opening direction is sometimes provided, and a first oil passage (25) for extending the hydraulic cylinder (15) is provided in the vicinity of the hydraulic cylinder (15). ) And a second oil passage (26) for shortening the hydraulic cylinder (15), a bypass oil passage (29) is provided, a relief valve (30) is provided in the bypass oil passage (29), and The relief valve (30) is a hydraulic oil from the second oil passage (26) to the first oil passage (25) when the pressure of the hydraulic oil supplied to the second oil passage (26) reaches a predetermined value. It is characterized by allowing distribution of Setting machinery of the grapple device.   The auxiliary machine (31) is attached to a case (16) of the hydraulic cylinder (15), and a bypass oil passage (29) and a relief valve (30) are provided in the auxiliary machine (31). Grapple equipment for construction machinery.

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