JPH0745673Y2 - Hydraulic circuit for gripping device - Google Patents

Description

[Detailed Description of Device] a. Object of the Invention (Field of Industrial Application) The present invention relates to a gripping device for gripping an object, and further to a hydraulic circuit for the gripping device in which the gripping force of the gripping device can be switched.

(Prior Art) A gripping device for gripping an object is composed of a gripping member that actually grips the object and a hydraulic actuating means such as a hydraulic cylinder that causes actuation (opening / closing operation) of the gripping member. In this case, the gripping force by the gripping member is determined according to the hydraulic pressure in the hydraulic cylinder.

On the other hand, for example, the applicant has provided a flexible arm at the tip of the boom, and a gripping device that can swing and rotate freely at the end of the boom. We proposed a grip type building pole work vehicle. The material of the electric pole, which is the object to be gripped by this gripping device, is a steel pipe,
There are multiple types such as concrete and wood, and the weight and compressive strength of utility poles differ depending on their materials.

(Problems to be Solved by the Invention) When the gripping force of the above-mentioned gripping device (operating hydraulic pressure of the hydraulic cylinder) is set corresponding to, for example, a relatively lightweight wooden utility pole, this gripping device Even if an attempt is made to grip a concrete utility pole, since the weight of the concrete utility pole is larger than that of the wooden utility pole, there is a possibility that the weight of the concrete utility pole is too large for the gripping force and cannot be gripped.

Further, when the gripping force is set corresponding to, for example, a steel-tube utility pole, when the gripping device grips a wooden utility pole, the compressive strength of the wooden utility pole is smaller than that of the steel-tube utility pole, so There is also a problem in that the holding force is too large for the compressive strength of the utility pole and the utility pole may be damaged.

In view of the above problems, it is an object of the present invention to provide a hydraulic circuit for a gripping device in which the gripping force of the gripping device can be switched according to the strength of each object.

B. Configuration of the Invention (Means for Solving the Problems) In order to achieve the above-mentioned object, in the present invention, the oil pump is arranged in a supply oil passage connecting an oil pump and a hydraulic operating means,
The operation control valve for controlling the operation of the gripping device by controlling the supply of the hydraulic oil to the hydraulic operating means, and the main oil passage connecting the oil pump and the operation control valve in the supply oil passage, are connected to the main oil passage. The main relief valve that opens this main oil passage to the oil tank when the oil pressure exceeds the predetermined relief pressure is connected to the supply oil passage in parallel with the main relief valve, and the oil pressure in the supply oil passage is higher than the predetermined relief pressure. The hydraulic circuit for the gripping device consists of a sub-relief valve that opens this supply oil passage to the oil tank when a low relief pressure is reached, and a gripping force switching valve that opens and closes the relief oil passage that connects the supply oil passage and the sub-relief valve. The predetermined relief pressure and the relief pressure of the sub-relief valve are set so as to correspond to the strength of each object. In addition, a plurality of sub-relief valves each having a different relief pressure are connected in parallel with each other to the supply oil passage, and the gripping force switching valve is selectively opened to the plurality of relief oil passages connecting the supply oil passage and these sub-relief valves. The position may be switchable between the open position for closing and the closed position for closing all the relief oil passages.

(Operation) By using the hydraulic circuit for the gripping device as described above, since the gripping force of the gripping device can be set to an appropriate force corresponding to the strength and weight of each object, the gripping device has a relatively large weight. It is possible to securely grip an object having high strength, and it is possible to grip an object having relatively weak strength without damage. Moreover, since the main relief valve is directly connected to the main oil passage, one or both of the operation control valve and the gripping force switching valve malfunctions, and the main oil passage and the relief oil passage are both blocked. Even in such a case, when the hydraulic pressure in the main oil passage exceeds a predetermined relief pressure, the main relief valve operates to protect the hydraulic circuit.

By providing multiple sub-relief valves and selectively opening or closing all of the relief oil passages by the gripping force switching valve, the relief pressure of the supply oil passage can be reduced by connecting the main relief valve and the multiple relief oil passages. Each relief pressure of the sub-relief valve can be selectively set, and the gripping force can be switched in three or more steps.

(Embodiment) Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

First, a gripping device whose operation is controlled by using the hydraulic circuit for the gripping device according to the present invention will be described with an example of its use.

FIG. 2A and FIG. 2B are a top view and a side view of a digging column vehicle (grip type digging column vehicle) equipped with a gripping device, respectively.

Outriggers 3 are respectively arranged at four front, rear, left and right sides of the body 2 of the grip-type digger / columner 1. When the work is performed, these outriggers 3 are extended and the body 2 is installed horizontally on the ground. Also,
A swivel base 4 is mounted on the rear part of the vehicle body 2.
Is rotatable by the operation of a swing motor (not shown). The boom 5 attached to this swivel base 4
It is composed of a base end side member 5a and a tip end side member 5b which is expandable and contractable with respect to the base end side member 5a. At the same time, the tip side member 5b is made to expand and contract by the expansion and contraction operation of an expansion and contraction cylinder (not shown) provided in the boom 5. Further, the swivel base 4 has a cabin for an operator to operate each actuator.
4a is attached.

On the other hand, an auger device (drilling device) 6 is attached to the tip of the base end member 5a of the boom 5. The auger device 6 is composed of an auger drill 6a and an auger motor 6b, the upper end of the auger drill 6a is connected to the output shaft of the auger motor 6b, and the upper part of the auger motor 6b is suspended on the boom 5. In addition, the auger device 6 is attached to the boom 5
It is also possible to fix it to the tip side member 5b, and in this case, the auger device 6 moves as the boom 5 expands and contracts. However, FIGS. 1A and 1B show the storage state when the auger device is not used.
Is attached to the base end side member 5 a of the boom 5. When performing a digging operation using the auger device 6, first, attach the auger device 6 to the tip side member 5b of the boom 5, move the auger device 6 to an arbitrary position by extending the boom 5, and the like. First, the auger device 6 is lowered so as to be perpendicular to the ground, and the auger motor 6b is rotated (see A in FIG. 5).

At the tip of the tip side member 5b of the boom 5, the gripper arm 7a is attached.
And gripper (grasping device) via the joint member 7c
7 is attached. The gripper 7 can perform bending and stretching operations centered on the connecting portion with the boom tip portion by the extension and contraction operation of the bending and stretching cylinder 7b attached between the gripper arm 7a and the tip portion of the boom 5.

A bucket (workbench) 8 for working at high places, which will be described later, is fixed to the right front part of the vehicle body 2 by a band 8a, and the bucket 8 can be used by removing the band 8a.

Further, utility pole pedestals 9 are provided on the front and rear portions of the vehicle body 2, respectively, on which utility poles can be placed for transportation.

Next, referring to FIG. 3A, FIG. 3B and FIG.
The configuration of will be described.

These figures are a top view, a side view, and a cross-sectional view taken along the plane FF, respectively, showing the periphery of the gripper 7.

The gripper 7 includes a pair of grip members 71 for gripping a utility pole, a gripper cylinder (hydraulic actuation means) 72 for opening and closing the grip member 71, and a link connecting the grip member 71 and the gripper cylinder 72. Mechanism (two link members 74 and guide members 75 are formed in a Y shape)
And a gripper housing 73 provided so as to cover the gripper cylinder 72 and extend rightward in the drawing (toward the grip member 71).

The left side (the side covering the gripper cylinder 72) of the gripper housing 73 has a cylindrical shape, and the right side has a prismatic shape. Further, the upper and lower surfaces of the right end of the gripper housing 73 are opened in a T shape, and the fulcrums 71b of the grip member 71 are pivotally attached to both ends of the T shape. Further, the grip member 71 is provided with an action point 71c offset inward from the fulcrum 71b, one end of each of the two link members 74 is pivotally attached to the action point 71c, and the other end of the link member 74 is Link members on the other side
It overlaps with the other end of 74 and is pivotally attached to one end of a guide member 75 that slides along the inner wall of the gripper housing 73, and the other end of the guide member 75 is connected to the piston rod 72a of the gripper cylinder 72.

In the gripper 7 having such a structure, when the gripper cylinder 72 is extended, the grip member 71 is pushed open outward around the fulcrum 71b, and when the gripper cylinder 72 is contracted, the grip member 71 is centered around the fulcrum 71b. For example, the electric pole 90 and the columnar gripped member 83 of the bucket 8 to be described later are gripped by being closed inside.

Since the guide member 75 is guided by the gripper housing 73, the grip member 71 is symmetrically opened and closed.

Further, in order to grip a comparatively small-diameter member such as the columnar gripped member 83, the grip member 71 is provided with notches 71e and 71e 'at the tip end thereof in a staggered manner.
The tips of the can intersect.

On the other hand, a cylindrical member 76 is attached so as to cover the prismatic portion of the gripper housing 73 (see FIGS. 3B and 3C), and further, the cylindrical member 76 is inserted in the cylindrical rotation support member 77. It penetrates and is rotatably attached to this. Further, a worm wheel 78 is attached to the outer periphery of the side surface of the cylindrical member 76 concentrically with the cylindrical member 76, and is rotatably attached to the worm wheel 78 and a support member 77a attached to the outside of the rotation support member 77. When the gripper rotation motor 79a connected to the worm pinion 79 is rotated, the worm wheel 78, that is, the gripper 7 is rotated.
Is rotated with respect to the rotation support member 77 (for example, the gripper 7 is rotated 90 ° until the state shown by the chain double-dashed line E in FIG. 3B is reached).

As shown in FIGS. 3B and 3C, the rotation support member 77 supports the side surface of the rotation support member 77 so as to be sandwiched from above and below by the joint member 7c. It is swingable around its support point.
Also, the horizontal swing cylinder 7d is attached to the lower end of the joint member 7c.
Is pivoted on its side surface, and the piston rod of the horizontal swing cylinder 7d pushes or pulls the swinging member 77b fixed to the support member 77a, whereby the gripper 7 moves to the 3A position.
From the position shown by the chain double-dashed line A in the figure to the position shown by the same B, it is swingable in the left-right direction, that is, it is swingable horizontally.

Further, the joint member 7c is pivotally attached to the tip of the gripper arm 7a, and the joint member 7c, that is, the gripper 7, is moved by the expansion and contraction operation of the vertical swing cylinder 7e attached between the joint member 7c and the gripper arm 7a. From the position shown by the chain double-dashed line C in FIG. 3B to the position shown by D in FIG.

In addition, as described above, the gripper arm 7a and the gripper 7 are flexed / extended integrally by the expansion / contraction operation of the flexion / extension cylinder 7b attached between the gripper arm 7a and the boom tip.

By controlling the vertical / horizontal swing of the gripper 7, the rotation and rotation of the boom, the ups and downs, and the bending and stretching of the gripper arm 7a, the electric pole mounted on the electric pole pedestal 9 in FIG. 1 is grasped and lifted, It is possible to carry out the building work without shifting from the building hole drilled by the above-mentioned drilling work (see B in FIG. 5).

Next, with reference to FIG. 4, a bucket for use by a worker to be used when working at a high place will be described.

The bucket 8 is composed of a box portion 81 on which an operator rides, and a columnar grasped member 83 whose upper and lower ends are supported by columnar supporting members 82 on the side surface of the box portion 81. When the bucket 8 is used Grips the columnar gripped member 83 by the grip member 71 of the gripper 7. In this way, after erection work of the utility pole, if the gripper 7 which has been gripping the utility pole until then grasps the bucket 8, it is possible to perform work at a high place such as wire drawing work of the constructed pole (fifth aspect). (See Figure C).

If the operation of the gripper 7 and the boom 5 described above is performed by the remote controller, when performing a digging / building operation, the worker can perform the work while confirming the building hole. In addition, when performing work in high places, the bucket 8
By operating the remote controller by himself / herself, the bucket 8 can be easily moved to a desired position.

Next, the gripper hydraulic circuit (grasping device hydraulic circuit) for supplying hydraulic oil to the gripper cylinder 72 (hydraulic operating means) for performing the gripping operation of the gripper 7 described above will be described with reference to FIG. explain.

A main oil passage 102 extends from the discharge port of the hydraulic pump 101, and a gripper opening / closing valve (operation control valve) 103 is connected to the oil passage 102. The gripper opening / closing valve 103 is a 4-port 3-position valve, has an input port P to which the main oil passage 102 is connected, two output ports A and B, and a drain port T connected to the tank 130, and further has a non-operating position ( It has a central position), a closing operation position (right position), and an opening operation position (left position), and is located at any position by excitation control of the left and right solenoids. The input port P and the drain port T are connected when the on-off valve 103 is in the non-actuated position. Two output ports A and B have
An oil passage 104 connected to the reduction-side oil chamber 72b of the gripper cylinder 72 and an oil passage 105 connected to the extension-side oil chamber 72c are connected to each other.

Pilot operated check valves 106a and 106b are provided on the oil passages 104 and 105, respectively.
When the hydraulic pressure in one of the oil passages reaches the cracking pressure of the check valve provided in the oil passage and hydraulic oil begins to pass through the check valve, a and 106b are upstream sides of the check valve, respectively. The other check valve is designed to be opened via the pilot oil passage that is connected from. These pilot-operated check valves 106a and 106b enable the reduction-side oil chamber
When the working oil is flowing into either one of the 72b and the extension side oil chamber 72c, the working oil in the other oil chamber is stored in the tank 130.
Can flow towards.

Next, a hydraulic circuit for setting the pressure of the hydraulic oil will be described.

An oil passage connected to the tank 130 in the middle of the main oil passage 102
110 is branched, and on this oil passage 110, a main relief valve 110a for setting the gripping force (that is, the working hydraulic pressure of the gripper cylinder 72) to the rated (maximum) gripping force of the gripper 7 is provided.
Is provided.

Further, a relief oil passage 121 branches from the main oil passage 102 downstream of the branch point of the oil passage 110, and this oil passage 121 is connected to the gripping force switching valve 123. This gripping force switching valve 123 is a 4-port 3-position valve, has an input port P to which the oil passage 121 is connected, two output ports A and B, and a drain port T connected to the tank 130, and further has a closed position (center). Position), a middle gripping force position (right position) and a small gripping force position (left position), and they are positioned at either position by excitation control of the left and right solenoids. The drain port P of the gripping force switching valve 123 is connected to the oil passage 11 via the oil passage 122.
It is connected to the downstream side of the main relief valve 110a of 0 and finally to the tank 130.

Each of the two output ports A and B has a relief oil passage 12
4 and 125 are connected, and these oil passages 124 and 125 are connected to the oil passage 110.
Is connected to the downstream side (tank 130 side) of the mounting position of the main relief valve 110a.

On the oil passage 124, a middle gripping force relief valve (sub-relief valve) 124a set to a relief pressure smaller than the relief pressure of the main relief valve 110a is attached. Also,
On the oil passage 125, a small gripping force relief valve (sub-relief valve) 125a set to a relief pressure smaller than the relief pressure of the medium gripping force relief valve 124a is attached.

Next, the operation of the gripper hydraulic circuit will be described.

For example, the relief pressure of the main relief valve 110a is set to a pressure at which the gripper 7 generates an appropriate gripping force for gripping the steel pipe utility pole by its operating hydraulic pressure, and the same applies to the middle gripping force relief valve. The relief pressure of 124a is set for the concrete utility pole, and the relief pressure of the small gripping force relief valve 125a is set for the wooden utility pole.

When the gripper 7 grips the steel pipe utility pole, first, the left and right solenoids of the gripping force switching valve 123 are de-energized based on the operation of the operator. At this time, the gripping force switching valve 123 is located at the closed position. Next, when the operator operates the gripper 7 to perform the closing operation, the right solenoid of the gripper opening / closing valve 103 is excited and the opening / closing valve 103 is switched to the closing operation position. Then, the hydraulic oil discharged from the hydraulic power source 101 flows into the reduction side oil chamber 72b of the gripper cylinder 72 via the main oil passage 102 and the oil passage 104, and the gripper cylinder 72
Is contracted, and the gripper 7 starts the closing operation accordingly. Thus, when the gripper 7 grips the steel pipe utility pole and the gripping force becomes an appropriate force for the steel pipe utility pole, that is,
When the working oil pressure reaches the relief pressure of the main relief valve 110a, the relief valve 110a opens and the working oil pressure does not rise any more. Therefore, the gripper 7 maintains the gripping force at this time.

When the gripper 7 is made to grip a concrete electric pole, the right solenoid of the gripping force switching valve 123 is excited based on the operation of the operator, and the spool moves to the left.
123 is located in the middle gripping force position. After that, by the same gripper closing operation as described above, the hydraulic oil is transferred to the main oil passage 10
2, reduction side oil chamber 72 of gripper cylinder 72 via oil passage 104
b, while the working hydraulic pressure is
The relief valve 124a for medium gripping force acts in a direction to open the relief valve 124a via the 124 and the pilot oil passage 124b. When the gripper 7 grips the concrete utility pole and the gripping force becomes an appropriate force for the concrete utility pole, that is, when the operating hydraulic pressure reaches the relief pressure of the intermediate gripping force relief valve 124a, the relief valve 124a Opens, and the rise in operating hydraulic pressure (grasping force) stops.

Further, when the gripper 7 is made to grip a wooden electric pole,
The left solenoid of the gripping force switching valve 123 is excited based on the operation of the operator, the spool moves to the right, and the switching valve 123 is positioned at the small gripping force position. At this time, the hydraulic oil is the main oil passage.
102 is supplied to the gripper cylinder 72, while the hydraulic pressure is supplied to the oil passages 121 and 125 and the pilot oil passage.
The relief valve 125a for small gripping force acts on the relief valve 125a via 125b in the opening direction. Then, when the gripping force of the gripper 7 becomes an appropriate force for the wooden utility pole, that is, when the operating oil pressure reaches the relief pressure of the small gripping force relief valve 125a, the relief valve 125a opens and the operating oil pressure ( Grasping force) stops increasing.

Since the relief pressures of the medium gripping force relief valve 124a and the small gripping force relief valve 125a are set to be smaller than that of the main relief valve 110a, the gripping force switching valve 123
The main relief valve 110a does not open when is positioned at the middle gripping force position or the small gripping force position. in this way,
The operator selects one of the main relief 110a, the medium gripping force relief valve 124a, and the small gripping force relief valve 125a to be actuated based on the material (strength) of the electric pole. The strength of the electric pole that holds the gripping force can be made appropriate. In addition, the gripper opening / closing valve 10
When one or both of 3 and the gripping force switching valve 123 have malfunctioned and the main oil passage 102 and the relief oil passage 121 are both blocked, the oil pressure in the main oil passage 102 is the main leaf. The main leaf valve 110a operates when the relief pressure of the valve 110a is exceeded. Therefore, the hydraulic pressure in the main oil passage 102 and the relief oil passage 121 is prevented from excessively rising, and the circuit is protected.

C. Effect of the Invention By using the hydraulic circuit for the gripping device as described above, the gripping force of the gripping device can be set to an appropriate force for strength and weight of each object. Therefore, the gripping device can surely grip an object having a relatively large weight and high strength, such as a steel pipe or concrete power pole, with a large gripping force commensurate with the strength and the weight, and like a wooden power pole. By gripping an object having a relatively low strength with a small gripping force commensurate with the strength, it is possible to prevent damage to the object due to an excessive gripping force. Moreover, since the main relief valve is directly connected to the discharge passage (main oil passage) of the oil pump, one or both of the operation control valve and the gripping force switching valve may malfunction and the main oil passage and the relief oil may be damaged. Even if both of the passages are blocked, the main relief valve operates when the hydraulic pressure in the main oil passage exceeds a predetermined relief pressure, and the hydraulic circuit is protected.

By providing multiple sub-relief valves and selectively opening or closing all of the relief oil passages by the gripping force switching valve, the relief pressure of the supply oil passage can be reduced by connecting the main relief valve and the multiple relief oil passages. It is possible to selectively set each relief pressure of the sub-relief valve of (3) to switch the gripping force in three or more steps.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a hydraulic circuit for a gripping device according to the present invention, and FIGS. 2A and 2B are gripping hole excavating structures equipped with grippers and attitude control means for controlling using the above circuits, respectively. 3A, 3B and 3C are a plan view and a side view of the cart, and FIG. 4A is a plan view, a side view and a sectional view of a gripper equipped on the grip type digging column vehicle. FIG. 5 is a perspective view showing a bucket mounted on the grip type digging column vehicle, and FIG. 5 is a conceptual diagram showing a working state using the grip type digging column vehicle. 7 ... Gripper, 72 ... Gripper cylinder 123 ... Gripping force switching valve 124a ... Medium gripping force relief valve 125a ... Small gripping force relief valve

Claims (2)

[Scope of utility model registration request] 1. A gripping device hydraulic circuit for supplying hydraulic oil discharged from an oil pump to a hydraulic operating means for driving a gripping device capable of gripping a plurality of types of objects having different strengths. An operation control valve which is disposed in a supply oil passage connecting the pump and the hydraulic operation means, and which controls the supply of the operation oil to the hydraulic operation means to control the operation of the gripping device; A main relief valve that is connected to a main oil passage that connects the oil pump and the operation control valve, and opens the main oil passage to an oil tank when the hydraulic pressure in the main oil passage exceeds a predetermined relief pressure; A valve that is connected to the supply oil passage in parallel with a relief valve and opens this supply oil passage to an oil tank when the hydraulic pressure in the supply oil passage exceeds a relief pressure lower than the predetermined relief pressure. A relief valve and a gripping force switching valve that opens and closes a relief oil passage that connects the supply oil passage and the sub-relief valve, and the predetermined relief pressure and the relief pressure of the sub-relief valve are the target objects. A hydraulic circuit for a gripping device, which is set so as to correspond to the strength of an object. 2. A plurality of the sub-relief valves each having a different relief pressure are connected to the supply oil passage in parallel with each other, and the grip force switching valve is a plurality of connecting the supply oil passage and these sub-relief valves. 2. The gripping device according to claim 1, wherein position switching is possible between an opening position for selectively opening the relief oil passages of the above and a closing position for closing all the relief oil passages. Hydraulic circuit.