JPH07241Y2 - Grapple saw hydraulic circuit - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hydraulic circuit of a grapple saw mounted on a tip of a work attachment of a hydraulic excavator or the like of a work vehicle.

2. Description of the Related Art FIG. 3 is a side view of a hydraulic excavator to which the grapple saw 1 is attached. In the figure, 2 is a work attachment mounted on the front part of the hydraulic excavator, 3 is a grapple device part of the grapple saw 1, 4 is a saw device part, 5 is a gripper device part 3 and is cut by the saw device part 4 or It is wood such as logs that are cut into pieces. FIG. 4 is a detailed view of part A of FIG. In the figure, 6 is a chain saw part of the saw device part 4, 7 is a cover member, 8 is a spring action member for returning the chain saw part 6, and arrow a is a cutting feed direction of the chain saw part. FIG. 5 is a perspective view of a main part of the saw device unit 4. In the figure, 9 is a hydraulic motor that only rotates forward to drive the chain saw portion 6, 10 is a saw feed cylinder that feeds the saw portion 6 by cutting, and 11 is a fluid communication with the head side air chamber of the saw feed cylinder 10. An air tank, 12 is a link member connecting the saw feed cylinder 10 and the chain saw section 6, and arrow B indicates the saw rotation direction of the chain saw section 6. FIG. 6 is a hydraulic circuit diagram of a conventional technique main part of a grapple saw. In the figure, 13 is a hydraulic motor switching valve for controlling the hydraulic motor 9, and 14
Is a hydraulic pump, 15 is a relief valve, 16 is a throttle part, 17 is a rod side oil chamber of the saw feed cylinder 10, 18 is a head side air chamber, 19 is an oil tank, and 20 is a stop valve for an air passage.

Next, the structure and function of the conventional hydraulic circuit will be described with reference to FIGS. The chain saw portion 6 of the grapple saw 1 can be rotationally driven by a hydraulic motor 9, and one downstream side of the hydraulic motor 9 communicates with a rod side oil chamber 17 of a saw feed cylinder 10 to set a feed oil passage 21. The other is communicated with the oil tank 19 via the throttle portion 16. When the hydraulic motor 9 rotates, the pressure oil on the downstream side of the hydraulic motor 9 is transferred to the rod-side oil chamber of the saw feed cylinder 10.
The cutting saw portion 6 is fed by being acted on 17 and the gripping wood 5 is cut into pieces.

Therefore, when the wood 5 is cut into pieces, the hydraulic motor switching valve 13 is switched from the c position to the two position. Hydraulic pump 14
The pressure oil from the oil passage 22
Through the hydraulic motor 9. At the same time that the hydraulic motor 9 rotates, the chain saw section 6 also rotates. Along with that, the pressure oil drawn from the downstream side of the hydraulic motor 9 is
It acts on the rod side oil chamber 17 of the saw feed cylinder 10 via the feed oil passage 23 and the feed oil passage 21. The piston part 24 in the saw feed cylinder 10 is connected to the air tank 11 and the head side air chamber 18
The air inside is compressed and moved in the direction of arrow E, and the cutting and feeding of the chain saw portion 6 is performed. When the chopping of the wood 5 is completed, the hydraulic motor switching valve 13 is operated to the original C position. Since the pressure oil from the hydraulic pump 14 is not supplied to the hydraulic motor 9, the hydraulic motor 9 stops and the rotation of the chain saw part 6 also stops. Since the oil pressure does not act on the rod side oil chamber 17 of the saw feed cylinder 10, the air tank 11
Also, due to the pneumatic pressure of the compressed air in the head side air chamber 18, the piston portion 24 is returned in the direction opposite to the arrow E. As a result, the chain saw unit 6 is returned to the original position direction when starting the ball cutting.

Problem to be solved by the invention When the cutting of the wood by the grapple saw is finished, the rotation of the chain saw part is stopped. Then, the chain saw part is returned to the original position direction at the start of the ball cutting, that is, the upward direction. However, in that case, the chain saw part may not be returned to its original position due to being caught by the cut surface part of the chopped wood or other protruding obstacles. Therefore, it takes a lot of time and labor to deal with the problem, and the work efficiency is lowered. Further, in the conventional grapple saw, when cutting a piece of wood, it is not possible to adjust the cut according to the size of the log diameter, the hardness of the material of the wood, the sharpness of the saw in the chain saw part, and the like.

The present invention solves the above-mentioned problems, and when the cutting of the wood is finished, the hydraulic circuit that can return the original position while rotating the chain saw part, and the cutting resistance applied to the chain saw part during the cutting An object of the present invention is to provide a hydraulic circuit capable of automatically adjusting the cutting conditions of the chain saw portion according to changes.

Means for Solving the Problems (1) a. A grapple saw is attached to the tip of the work attachment of the work vehicle, and the chain saw part of the grapple saw can be rotationally driven by a hydraulic motor.One of the downstream sides of the hydraulic motor communicates with the rod side oil chamber of the saw feed cylinder to feed A grapple saw in which an oil passage is set and a chain saw portion is rotatably connected to a cylinder rod portion to perform a chopping operation for grasping timber. A saw feed switching valve is provided in the feed oil passage, and by switching the saw feed switching valve, the chain saw portion is returned to its original position without stopping the rotation of the chain saw portion hydraulic motor.

(2) b. A grapple saw is attached to the tip of the work attachment of the work vehicle, and the chain saw part of the grapple saw can be rotationally driven by a hydraulic motor.One of the downstream sides of the hydraulic motor communicates with the rod side oil chamber of the saw feed cylinder to feed An oil passage is set, and the other one is made to communicate with the oil tank via the throttle portion, and when the hydraulic motor is rotating, the pressure oil on the downstream side of the hydraulic motor is made to act on the saw feed cylinder to feed the chain saw portion by cutting. In a grapple saw designed to perform chopping work on grasped timber, b. The throttle portion is set as a variable throttle portion, the throttle opening degree of the variable throttle portion can be adjusted by the hydraulic pressure on the upstream side of the hydraulic motor, and the rod side oil chamber pressure of the saw feed cylinder can be adjusted.

Action (1) a. When the chopping of the wood is completed, the switching valve for the hydraulic motor is not operated, and the switching valve for the saw feed is operated to switch from the original position of the open oil passage to the position of the tank communicating oil passage.

B. According to the above item (a), the rod-side oil chamber of the saw feed cylinder communicates with the oil tank via the tank communication oil passage position of the saw feed switching valve.

C. According to the above items (a) and (b), after the cutting of the wood is finished, the chain saw part is returned to its original position while rotating as in the case of cutting.

(2) b. The opening degree of the variable throttle portion provided in the tank communication passage on the downstream side of the hydraulic motor is adjusted by the hydraulic pressure on the upstream side of the hydraulic motor.

B. When cutting a piece of wood, for example, when excessive excavation resistance is applied to the chain saw portion, the hydraulic pressure on the upstream side of the hydraulic motor increases. As the hydraulic pressure rises, the diaphragm aperture of the variable diaphragm section increases. Therefore, the hydraulic pressure in the hydraulic motor downstream side, that is, in the rod-side oil chamber of the saw feed cylinder decreases. As a result, the cutting feed of the chain saw section is automatically reduced.

C. On the contrary to the above item (b), when the cutting resistance is relatively small, the throttle opening degree of the variable throttle portion becomes small and the rod side oil chamber oil pressure of the saw feed cylinder rises. As a result, the cutting feed of the chain saw section automatically increases.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a hydraulic circuit diagram of claim 1 of the present invention. In the figure, the same reference numerals are given to those using the same constituent elements as those in the prior art. 25 is a saw feed switching valve, 26 is a saw feed switching valve 25 solenoid, 27 is an electric circuit,
28 is a switch and 29 is a power supply.

Next, the construction and operation of the hydraulic circuit according to the first aspect of the present invention will be described with reference to FIG. A saw feed switching valve 25 is provided in a feed oil passage that connects the downstream side of the hydraulic motor 9 and the rod side oil chamber 17 of the saw feed cylinder 10, and the saw feed switching valve 25 is switched by operating a switch 28. Configured possible. Therefore, when the switch 28 is turned off, the electric circuit 27 is not energized, so that the saw feed switching valve 25 is in the open oil passage position. This case is similar to the case of the hydraulic circuit of the related art. However, when the chopping of the wood is finished, the switch 28 for the hydraulic motor is not turned on but the switch 28 is turned on. Since the solenoid 26 is energized, the saw feed switching valve 25 switches from the open oil passage position to the tank communication oil passage position. The rod side oil chamber 17 of the saw feed cylinder 10 communicates with the oil tank 19 via the feed oil passage 30 and the tank communication oil passage position of the saw feed switching valve 25. As a result, no hydraulic pressure acts on the rod-side oil chamber 17, so that the chain saw portion 6 is returned to the original position at the start of the ball cutting operation while performing cutting rotation.
Even if the chain saw portion 6 comes into contact with another projecting obstacle, for example, during the process, the projecting obstacle can be cut and returned to the original position.

In this embodiment, the solenoid valve is operated as the saw feed switching valve 25.However, the hydraulic pilot type saw feed switching valve (shown in the figure) is switched by operating the pilot pressure from the pilot pressure hydraulic source. No) may be used instead of the solenoid valve.

Next, FIG. 2 is a hydraulic circuit diagram of claim 2 of the present invention. In the figure, 31 is a variable diaphragm unit. The configuration and operation of the hydraulic circuit according to claim 2 will be described with reference to FIG. The throttle portion provided in the tank communication passage on the downstream side of the hydraulic motor 9 is set to the variable throttle portion 31, and the throttle opening degree of the variable throttle portion 31 can be adjusted by the hydraulic pressure on the upstream side of the hydraulic motor 9. Therefore, when cutting wood, for example, when an excessive cutting resistance is applied to the chain saw portion 6, the oil pressure in the oil passage 22 on the upstream side of the hydraulic motor 9 increases. The oil pressure acts on the variable throttle portion 31 through the pilot oil passage 32 to increase the aperture opening degree of the variable throttle portion 31. Therefore, the hydraulic motor 9 downstream side, that is, the saw feed cylinder
The oil pressure in the rod-side oil chamber 17 of 10 decreases. As a result, the cutting feed of the chain saw section 6 is automatically reduced. Further, when the cutting resistance of the chain saw section 6 is relatively small, the diaphragm aperture of the variable diaphragm section 31 becomes small. By the operation opposite to the above, the cutting feed of the chain saw portion 6 automatically increases. In this way, the cutting conditions of the chain saw portion 6 can be automatically adjusted according to the change in the cutting resistance applied to the chain saw portion 6 when cutting a piece of wood.

Effect of the Invention In the grapple saw of the related art, the rotation of the chain saw portion is stopped when the cutting of the wood is finished. Then, the chain saw part is returned to the original position direction at the start of the ball cutting, that is, the upward direction. However, in that case, the chain saw part may not be returned to its original position due to being caught by the cut surface part of the chopped wood or other protruding obstacles. Therefore, it takes a lot of time and labor to deal with the problem, and the work efficiency is lowered. Further, in the conventional grapple saw, when cutting a piece of wood, it is not possible to adjust the cutting feed in accordance with the size of the log diameter, the material hardness of the wood, the saw sharpness of the chain saw part, and the like. .

However, in the hydraulic circuit according to claim 1 of the present invention, when the switch is operated, the saw feed switching valve provided in the feed oil passage is switched to operate, and the chain saw portion is rotated in its original position without stopping the rotation of the chain saw portion. I went back to.
Thus, even if the chain saw portion comes into contact with another projecting obstacle during the returning, the projecting obstacle can be cut and returned to the original position. In the hydraulic circuit according to the second aspect of the present invention, the variable throttle portion is provided in the tank communication passage on the downstream side of the hydraulic motor, and the throttle opening degree of the variable throttle portion can be adjusted by the hydraulic pressure on the upstream side of the hydraulic motor. As a result, the cutting conditions of the chain saw section can be automatically adjusted according to changes in the cutting resistance applied to the chain saw section during cutting of wood.

Therefore, in the grapple saw with the hydraulic circuit of the present invention, it is possible to improve the functionality and workability of the chain saw section.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of claim 1 of the present invention, FIG. 2 is a hydraulic circuit diagram of claim 2 of the present invention, FIG. 3 is a side view of a hydraulic excavator having a grapple saw attached, and FIG. 3 is a detailed view of a portion A in FIG. 3, FIG. 5 is a perspective view of a main portion of a saw device portion, and FIG. 6 is a hydraulic circuit diagram of a main portion of a conventional technique. 1 Grapple saw 5 Wood 6 Chain saw 9 Hydraulic motor 10 Saw feed cylinder 11 Air tank 12 Link member 13 Hydraulic motor switching valve 17 Rod side oil chamber 25 …… Saw feed switching valve 28 …… Switch 31 …… Variable throttle

Claims (2)

[Scope of utility model registration request] 1. A grapple saw is attached to a tip of a work attachment of a work vehicle, a chain saw portion of the grapple saw can be rotationally driven by a hydraulic motor, and one downstream side of the hydraulic motor is a rod side oil chamber of a saw feed cylinder. In the grapple saw in which the feed oil passage is set in communication with the cylinder rod and the chain saw portion is rotatably connected to the cylinder rod portion to perform the chopping work of the gripped wood, the saw feed switching valve is provided in the feed oil passage. A hydraulic circuit for a grapple saw, wherein the chain saw unit is returned to its original position and actuated without stopping the rotation of the chain saw hydraulic motor by switching the saw feed switching valve. 2. A grapple saw is attached to a tip of a work attachment of a work vehicle, a chain saw portion of the grapple saw can be rotationally driven by a hydraulic motor, and one downstream side of the hydraulic motor is a rod side oil chamber of a saw feed cylinder. To establish a feed oil passage in communication with the oil tank, and the other to communicate with the oil tank via the throttle.When the hydraulic motor rotates, the pressure oil on the downstream side of the hydraulic motor acts on the saw feed cylinder to allow In a grapple saw that cuts and feeds and cuts timber of gripping wood, the throttle part is set as a variable throttle part, and the throttle opening degree of the variable throttle part can be adjusted by the hydraulic pressure on the upstream side of the hydraulic motor. The hydraulic circuit of the grapple saw is characterized in that the pressure in the oil chamber on the rod side of the saw feed cylinder can be adjusted.