JP3046870U - Hydraulic cylinder interlock control circuit - Google Patents

Abstract

(57) [Problem] To provide a hydraulic circuit in which forward and backward movement is automatically reversed when a piston of a hydraulic cylinder stops due to overload. SOLUTION: An automatic switching valve is interposed between a directional control valve and a rod-side and / or head-side oil chamber of a hydraulic cylinder, and the automatic switching valve is set to be in a non-operating position in a no-load state. When the hydraulic oil flows into the automatic switching valve from the directional control valve, the pilot pressure is used to switch to the operating position and send the hydraulic oil to the rod-side or head-side oil chamber, where the piston of the hydraulic cylinder stops and the rod-side or head-side When the hydraulic oil inlet pressure in the oil chamber rises, the pilot pressure switches the automatic switching valve to the non-operating position and switches the directional control valve to the opposite position.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a control circuit for continuously driving a hydraulic cylinder, and more particularly to a control circuit for a bucket built in a crusher mounted on a work vehicle such as a hydraulic shovel.

[0002]

[Prior art]

 When a hydraulic cylinder is used in a jaw crusher, it is necessary to continuously extend and retract the rod of the cylinder in order to continuously drive the rocking plate. The bucket built into the crusher is a type of jaw crusher, and is used by being mounted on a work vehicle such as a hydraulic shovel, and an example of a hydraulic control circuit of a rocking plate mounted inside is disclosed in JP-A-8-150344. It has been disclosed.

In Japanese Unexamined Patent Publication No. 8-150344, in the description related to FIG. 4 of the accompanying drawings, the piston rod 32b of the hydraulic cylinder 32 for driving the rocking plate is located at the top dead center and the bottom dead center (both stroke ends). When it is located, the valve 61 is switched via a cam mechanism and a lever which comes into contact with the rod, and the valve operates the switching valve 60 for supplying hydraulic oil to the oil chamber on the rod side or the head side of the hydraulic cylinder 32. . By operating the changeover switch 82 in FIG. 9 and the limit switches 83A and 83B in FIG. 10, a signal is sent to the solenoid valve 81 to switch the connection state of the main pipeline.

[0004]

[Problems to be solved by the invention]

 In a crusher or crusher of this type, if a large hard concrete mass or rock is caught and cannot be crushed in one stroke, and the rocking plate stops in the middle of the stroke, the crushing work is temporarily stopped. Then, it is necessary to retreat the rocking plate in the separating direction to make a gap, and to remove the caught foreign matter. In this case, if the mechanism does not reverse the movement of the rocking plate during the stroke as in Japanese Patent Application Laid-Open No. 8-150344, artificial means such as manually removing the caught foreign matter using a hammer or lever is used. As a result, the rocking plate must be forcibly retracted to remove the foreign matter, and it takes a considerable amount of time and labor to take measures when a foreign matter that is difficult to crush is caught, resulting in a drastic reduction in work efficiency.

On the other hand, if the crusher or the crusher incorporates a changeover switch or a limit switch and an electric device such as a solenoid valve, it is necessary to supply power from the hydraulic shovel side. For this reason, it is necessary to install and connect the power cable before use, which causes inconvenience, such as the time required for installation work as well as the preparation of auxiliary facilities.

An object of the present invention is to solve the above-mentioned problem in the continuous operation of the hydraulic cylinder, particularly in the bucket built in the crusher without using an electric control means such as a switch or a solenoid valve. An object of the present invention is to provide an interlocking control circuit that automatically switches a directional control valve to an opposite position when a piston of a hydraulic cylinder stops. Another object of the present invention is to provide a crusher capable of automatically reversing the movement of a rocking plate during the stroke of the rocking plate when the object is difficult to crush, thereby enabling continuous operation without stopping the rocking plate. The object is to provide a control circuit for the built-in bucket.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, the control circuit according to the present invention includes a two-way directional control valve installed in two main conduits connected to the rod side and the head side oil chamber of the hydraulic cylinder, and the rod side. And / or interpose an automatic switching valve between the head side oil chamber and the direction control valve. This automatic switching valve is set so as to be in the non-operating position in a no-load state, and when hydraulic oil flows into the automatic switching valve from the directional control valve, it is switched to the operating position by the pilot pressure and the hydraulic oil is switched to the rod side. Or send it to the head side oil chamber. When the hydraulic cylinder piston stops and the hydraulic oil inflow pressure in the rod-side or head-side oil chamber increases, the pilot pressure switches the automatic switching valve to the non-operating position and switches the direction control valve to the opposite position. .

[0008] The control circuit according to the present invention includes two directional control valves installed in two main pipelines connected to the rod-side and head-side oil chambers of the hydraulic cylinder, and a rod-side and / or head-side oil chamber. A branch passage may be provided between the directional control valve and the branch passage so that the hydraulic oil flows through the relief valve and the check valve to return to the main pipeline near the directional control valve. When the hydraulic cylinder piston stops and the hydraulic oil inflow pressure in the rod-side or head-side oil chamber rises, the relief valve is activated and the directional control valve is switched to the opposite position by the discharged oil.

The control circuit of the present invention is preferably applied to a bucket with a built-in crusher as illustrated in FIG. The bucket built into the crusher is usually rotatably mounted near the rear opening of the bucket frame with the hydraulic cylinder housed in the bucket frame, and moves closer to or away from the fixed wall by the expansion and contraction operation of the hydraulic cylinder. It has a rocking plate and a bracket portion provided with a pin hole for mounting on a work carriage arm such as a hydraulic shovel.

In the control circuit of the present invention, one of the two main pipelines connecting the circuit configuration including the automatic switching valve and the circuit configuration including the relief valve to the rod side of the hydraulic cylinder and the oil chamber on the head side. Can be connected one by one. In addition, it is also possible to connect only one of the circuit having the automatic switching valve and the circuit having the relief valve to each of the two main pipelines. In this specification, normally, the directional control valve is a two-way pilot hydraulically operated two-position four-way valve, and the automatic switching valve may be a two-way pilot hydraulically operated two-position three-way valve.

[0011]

[Embodiment of the invention]

 6 to 8 show an example of a crusher built-in bucket equipped with the control circuit of the present invention. The bucket 20 with a built-in crusher includes a hydraulic cylinder 1 housed in a bucket having a rectangular cross section surrounded by four side walls, and a swinging plate 25 approaching / separating from the fixed wall 23 by the expansion / contraction operation of the hydraulic cylinder 1. The swing plate 25 has its rear end rotatably mounted near the rear opening of the bucket frame. A valve block 50 incorporating a hydraulic device is attached to the hydraulic cylinder 1.

The hydraulic source of the control circuit is, for example, a driving hydraulic pump 5 (FIG. 1) such as a hydraulic shovel. Usually, between the hydraulic pressure source and the valve block 50, a three-position, four-way hydraulically operated valve 6 installed in the cab of the hydraulic shovel is interposed. A hydraulic pipe (not shown) is attached along the arm 39 of the hydraulic shovel so that the hydraulic operation valve 6 can control the expansion and contraction operation of the hydraulic cylinder 1, and the distal end thereof is connected to the connection 38 (FIG. 6 or FIG. 8). To the hydraulic cylinder 1 via

In the control circuits shown in FIGS. 1 to 3, the frames 50, 50 ', and 50 "indicated by alternate long and short dash lines are formed as valve blocks, and the entire block does not have to be individually connected between hydraulic devices. 6, the valve block 50 is compactly configured and attached to the body of the hydraulic cylinder 1. The valve block 50 may be installed at a position distant from the hydraulic cylinder 1.

In the valve block 50, for example, as shown in FIG. 3, a two-way pilot hydraulic actuation type that alternately switches a hydraulic oil supply direction from a hydraulic source to a main pipeline connected to both oil chambers 3 and 4 of the hydraulic cylinder 1. The directional control valve 7 of the 2-position 4-way valve is interposed. The directional control valve 7 includes a spring 17 for biasing its own spool (not shown). When the pilot pressures of the pilot hydraulic chambers N and O at the left and right ends of the spool are substantially the same by the spring, a hydraulic pressure source is provided. Is connected to a circuit leading to the head-side oil chamber 3.

The automatic switching valve 8, which is a two-way pilot hydraulically operated two-position three-way valve, is interposed, for example, in a main line connecting the head-side oil chamber 3 and the output port of the direction control valve 7. The automatic switching valve 8 includes a spring 16 for biasing its own spool (not shown), and when the pilot pressures of the pilot hydraulic chambers Q and R at the left and right ends of the spool are substantially the same (see FIGS. 3 and 5). The spring 16 communicates the hydraulic pressure source with the pilot hydraulic chamber O of the direction control valve 7 and shuts off the pilot hydraulic chamber Q on the same side as the spring 16 from the hydraulic pressure source. The spring 16 is preferably set to have a slightly lower elasticity than the spring 17 of the direction control valve 7.

When the flow of hydraulic oil into the head-side oil chamber 3 stops, the automatic switching valve 8 moves its own spool (not shown) due to the pressure increase in the head-side oil chamber 3. As a result, the input port G of the automatic switching valve 8 communicates with the pilot hydraulic chamber O of the direction control valve 7, and the spool is automatically switched in the opposite direction.

In the automatic switching valve 8, one port H of both output ports is directly connected to the port K of the cylinder 1, and the other port I is connected to the pilot hydraulic pressure of the directional control valve 7 via the throttle 14 and the check valve 10. Further, a pipe VG is provided from the check valve 10 to the input port G of the automatic switching valve 8 in communication with the chamber O, and a check valve 11 with a back pressure regulation incorporating a spring 18 is provided in the pipe. By intervening, only the flow from the check valve 10 to the input port G is allowed. The spring 18 of the check valve 11 is preferably set to have a slightly higher elasticity than the spring 17 of the direction control valve 7. The throttle 14 may be provided at any point in the pipeline from the position shown in FIG. 3 to the position of the check valve 10.

On the right side of FIG. 3, a return line KS is further provided with a check valve 12 interposed therebetween, and the return line is connected from the port K of the cylinder 1 to the output port F of the directional control valve 7. Only the flow toward is allowed. In this specification, regarding the description of the pipeline connection, for example, even if the pipeline from the port K is connected between the pipeline between the check valve 12 and the port K, the pipeline is connected to the port K or the check valve. It should be understood that the direct connection to the port of valve 12 is substantially the same, and this applies in other cases as well.

On the other hand, on the left side of FIG. 3, a branch line L is connected to a main line EJ extending from the direction control valve 7 to the rod-side oil chamber 4 of the hydraulic cylinder 1, and the branch line is connected to a relief valve 9. Then, the flow returns to the main line EUJ through the check valve 13. The relief valve 9 that operates to discharge oil at the maximum operating pressure of the cylinder 1 communicates its discharge port M with the pilot hydraulic chamber N of the directional control valve 7, and further discharges oil through the check valve 13 to the line M- Flow in the direction of U.

Next, the switching operation automatically performed by the direction control valve 7 will be described. When the operation valve 6 is pulled to the left at the valve position shown in FIG. 3, the hydraulic pressure source communicates with the input port G of the automatic switching valve 8 through the operation valve 6, the direction control valve 7 and the line FG, and The pressure increased by the resistance acts on the pilot hydraulic chamber R of the automatic switching valve 8. As a result, the automatic switching valve 8 overcomes the spring 16 and pushes the spool to the left to reach the valve position shown in FIG. 4, and the hydraulic oil flows into the head side oil chamber 3 of the hydraulic cylinder 1 from the line FG. In the hydraulic cylinder 1, the piston is pushed out and extended, and the hydraulic oil in the rod-side oil chamber 4 is discharged from the port J and returned to the tank 15.

In the valve position shown in FIG. 4, the pilot hydraulic chamber Q of the automatic switching valve 8 communicates with the port H. However, since the pressure drop due to the passage resistance between the ports G and H is large, the pilot hydraulic chamber R Is larger than the sum of the acting force of the pilot hydraulic chamber Q and the elasticity of the spring 16. Therefore, the automatic switching valve 8 maintains the valve position shown in FIG. 4, and the hydraulic cylinder 1 continues the extension operation.

In this extension stroke, the hydraulic cylinder 1 reaches the end of its stroke, or the crusher bites hard foreign matter that is difficult to crush, and the rotation of the rocking plate 25 stops. When the inflow stops, the flow between ports G and H stops, and both ports have the same pressure, and pilot hydraulic chambers Q and R also have the same pressure. As a result, in the automatic switching valve 8, the spool 16 is pushed rightward by the spring 16, and high-pressure hydraulic oil flows into the pilot hydraulic chamber O via the line FG, the throttle 14, the check valve 10, and the like (see FIG. 3), push the spool of the directional control valve 7 to the left.

At this time, the hydraulic oil in the pilot hydraulic chamber N is discharged from the pipe NU to the tank 15 through the check valve 13, and the direction control valve 7 is switched in the opposite direction to change the direction in FIG. Valve position. In FIG. 5, the hydraulic oil from the hydraulic source flows into the rod-side oil chamber 4 of the hydraulic cylinder 1 via the ports P, A, C, E, and the pipeline EJ. When the piston 2 contracts, the hydraulic oil in the head-side oil chamber 3 is discharged from the port K and returned to the tank 15 via the pipe KSF with the check valve 12.

During this reduction stroke, when the hydraulic cylinder 1 reaches the stroke end and the rotation of the swing plate 25 stops, and the hydraulic oil on the supply side reaches the maximum working pressure of the crusher, the relief valve 9 is activated. When opened, the hydraulic oil acts on the pilot hydraulic chamber N via the branch passage MN to push the spool of the directional control valve 7 rightward. As a result, the hydraulic oil in the pilot hydraulic chamber O is discharged to the tank 15 via the line OV, the check valve 11 with back pressure regulation, and the like, and switches the direction control valve 7 to the position shown in FIG. . Thereafter, the spool of the automatic switching valve 8 is pushed to the left as described above, and the process returns to the extension stroke of FIG. 4 again.

The directional control valve 7 cooperates with a circuit including an automatic switching valve 8 and / or a relief valve 9, and by alternately reversing the operation position as described above, the bucket 20 built in the crusher is automatically turned. The crushing operation can be continued. That is, in the embodiment of FIG. 1, the circuit configuration having the relief valve 9 on the left side of FIG. 3 is replaced with the circuit configuration having the automatic switching valve 8 on the right side of FIG. On the other hand, in the embodiment of FIG. 2, the circuit configuration having the automatic switching valve 8 on the right side of FIG. 3 is replaced with a circuit configuration having the relief valve 9 on the left side of FIG.

[0026]

【Example】

 Next, the present invention will be described based on embodiments, but the present invention is not limited to the embodiments. 6 and 7 show a bucket 20 with a built-in crusher employing the control circuit of the present invention. In FIG. 8, the bucket 20 is mounted on a hydraulic excavator, and the bucket is used to crush concrete blocks and the like. I have.

The crusher built-in bucket 20 includes a bucket frame having a rectangular cross section surrounded by four side walls having front and rear openings 21 and 22, a hydraulic cylinder 1 housed in the bucket frame, and a telescopic operation of the hydraulic cylinder 1. And a bracket 35 provided with pin holes 37, 37 for mounting on an arm 39 of a work cart such as a hydraulic shovel. In this bucket frame, left and right side walls 24 and 24 and upper and lower walls 23 and 31 form openings 21 and 22 having a rectangular cross section and a wider front. In the bracket 35, the pin holes 37, 37 are formed through the pair of side plates 36, 36.

The rocking plate 25 is rotatably supported at its rear portion in the vicinity of the opening 22 behind the bucket by a shaft 30 supported by bearings 29, 29 fixed to both side walls 24, 24. ing. A connecting member 27 is fixed to the upper rear surface of the rocking plate 25, and the rod end of the hydraulic cylinder 1 is pivotally mounted on the connecting portion by a pin 32. In the hydraulic cylinder 1, tube ends are pivotally mounted on bracket side plates 36, 36 adjacent to the upper wall 31 with pins 33. A crushing plate 23a is attached to the inner surface of the lower wall as the fixed wall 23, while a crushing plate 26a is attached to the swinging plate 25. The swinging plate 25 approaches and separates from the fixed wall 23 due to the expansion and contraction operation of the hydraulic cylinder 1, thereby crushing the object taken in between the swinging plate 25 and the fixed wall 23.

The bucket 20 is provided with a plurality of digging teeth 42 at the edge of the front wall to facilitate digging of the crushing target. At the bucket opening 21, a partition plate 28 is provided upward from the tip of the swinging plate 25, and the partition plate is curved in an arc shape about the axis 30, while being provided in front of the side walls 24, 24. The guide plate 34 is mounted diagonally, and the guide plate comes into contact with the partition plate 28, thereby guiding the crushed object 55 to be crushed rearward and preventing it from entering the cylinder 1 side. Hydraulic connections 38, 38 are fixed above both sides of the bucket 20, and are connected to the connection 38 from the drive pump 5 (see FIG. 3) of the excavator 1 via a pipe (not shown) attached along an arm 39. Hydraulic cylinder 1 is supplied with hydraulic oil via 50.

The bucket 20 can be rotated by the arm 39 of the hydraulic excavator and the operation cylinder 41 of the bucket link 40, and can easily shift from the position shown in FIG. 6 to the position shown in FIG. The bucket 20 scoops up a crushed object 55 such as a concrete lump in the front opening 21, crushes the crushed object 55 by the expansion and contraction operation of the hydraulic cylinder 1, and discharges the fine particles 56 from the rear opening 22.

FIGS. 3 to 5 show an example of the control circuit of the present invention. In FIG. 3, the hydraulic oil for driving the crusher built-in bucket 20 is also used as the hydraulic oil discharged from the hydraulic pump 5 for driving the hydraulic shovel, and the hydraulic oil is supplied by the operating valve 6 installed on the hydraulic shovel. And shut off, that is, the operation and stop of the hydraulic cylinder 1 are controlled. The oil discharged from the hydraulic pump 5 is guided from the operator cab of the hydraulic excavator to the primary input port P of the operation valve 6 of a three-position, four-way valve operated by a pedal or the like. To the secondary output ports A and B connected to the reciprocating pipe to the hydraulic cylinder 1 side or the primary port T returning to the tank 15.

A directional control valve 7, which is a two-way pilot hydraulically operated two-position four-way valve, is interposed between two main lines connecting the operation valve 6 and the hydraulic cylinder 1. Is alternately switched to the rod side of the hydraulic cylinder 1 and the head side oil chambers 3, 4. The directional control valve 7 is provided with pilot hydraulic chambers N and O at the left and right ends of a spool (not shown), and further includes a spring 17 for biasing the spool, so that the hydraulic oil in both hydraulic chambers N and O can be substantially reduced. When the pressure is the same, the hydraulic pressure source normally communicates with the circuit side of the hydraulic cylinder 1 which reaches the head side oil chamber 3.

In FIG. 3, a two-way pilot is connected to a main conduit FSGGHK from a port F of a direction control valve 7 provided in a main conduit of the hydraulic cylinder 1 to a head side oil chamber 3 of the hydraulic cylinder 1. The hydraulically operated automatic switching valve 8 is interposed. In the automatic switching valve 8, one port H of the output port is directly connected to the port K of the cylinder 1, and the other port I is connected to the pilot hydraulic chamber O of the directional control valve 7 via the throttle 14 and the check valve 10, respectively. Communicate. A pipeline VG is provided from a pipeline between the check valve 10 and the pilot hydraulic chamber O to an input port G of the automatic switching valve 8, and a back pressure regulating check having a spring 18 built in the pipeline. By interposing the valve 11, only the flow from the check valve 10 to the port G is allowed.

The automatic switching valve 8 is a two-position three-way valve. Two pilot hydraulic chambers Q and R are provided at the left and right ends of a spool (not shown), and a spring 16 for urging the spool to the hydraulic chamber Q is provided. When the pilot pressures of the two hydraulic chambers Q and R are substantially the same (see FIGS. 3 and 5), the hydraulic source is connected to the circuit side of the directional control valve 7 which communicates with the pilot hydraulic chamber O. The pilot hydraulic chamber Q on the same side as the spring 16 is shut off from the hydraulic pressure source. Further, a return line KS with a check valve 12 interposed is provided. The return line is connected from the port K of the cylinder 1 to the output port F of the directional control valve 7 and the input port G of the automatic switching valve 8. Only the incoming flow is allowed.

On the other hand, on the left side of FIG. 3, a branch line L is connected to a main line EJ extending from the direction control valve 7 to the rod-side oil chamber 4 of the hydraulic cylinder 1, and the branch line is connected to a relief valve 9. And returns to the same main line via the check valve 13. In other words, the discharge port M of the relief valve 9 communicates with the pilot hydraulic chamber N of the direction control valve 7 and provides a pipe returning from the pipe M-N to the same main pipe via the check valve 13. . The relief valve 9 discharges oil at the maximum operating pressure of the cylinder 1, and the discharged oil flows only through the check valve 13 from the line MN to the main line.

In this control circuit, when the hydraulic operation valve 6 is switched to the left as shown in FIG. 4 when the valve is in the valve position shown in FIG. 3, the hydraulic pump 5 of the hydraulic source is connected to the ports P and A of the operation valve 6. After passing through the ports C and F of the directional control valve 7 in sequence, it is in communication with the port G of the automatic switching valve 8. At this time, since the spring 16 of the automatic switching valve 8 is set slightly weaker than the spring 17 of the direction control valve 7, the pressure of the port G rises due to the resistance of the throttle 14 between the ports GI, Before the directional control valve 7 is switched, the spool of the automatic switching valve 8 is pushed to the left as shown in FIG. 4, and the hydraulic oil from the hydraulic pressure source flows from the port G to the port H.

With this hydraulic oil, the pressure on the port H side drops slightly due to the passage resistance from the port G to the port H. As a result, even if the port H communicates with the pilot hydraulic chamber Q of the automatic switching valve 8, the pressure of the port G, that is, the pressure of the pilot hydraulic chamber R, is a resultant force of the slightly reduced pilot pressure and the elasticity of the spring 16. The spool is maintained at the position shown in FIG.

The hydraulic oil that has passed through the ports G and H flows into the cylinder head side oil chamber 3 from the port K of the hydraulic cylinder 1, pushes the piston 2 to the left, and the hydraulic cylinder 1 is extended. On the other hand, the hydraulic oil in the rod-side oil chamber 4 is discharged from the port J, reaches the directional control valve 7 through the main pipeline JLUE, and furthermore, the ports E and D and the ports of the operation valve 6. After returning to B and T, the tank 15 is returned. By the extension operation of the hydraulic cylinder 1, the rocking plate 25 of the crusher built-in bucket 20 is turned toward the fixed plate 23, and the object between the rocking plate and the fixed wall 23 is crushed.

The oscillating plate 25 stops when the hydraulic cylinder 1 extends to the stroke end or when the bucket 20 bites hard foreign matter that is difficult to crush during the stroke, whereby the flow of the hydraulic oil in the main circuit is caused. Stops. As a result, in the automatic switching valve 8, the passage resistance disappears between the ports G and H, and the pressure becomes the same, and the force for pushing the spool to the right or left coincides. Switching to the direction, the port G communicates with the port I through the throttle 14, and guides the hydraulic oil in the port G to the pilot hydraulic chamber O of the direction control valve 7 through the throttle 14, the port I, and the check valve 10. At this time, since the pilot hydraulic chamber N of the directional control valve 7 communicates with the tank 15 via the check valve 13 and the like, the rightward biasing force of the spool of the directional control valve 7 is only the elasticity of the spring 17. 5, the pressure acting on the pilot hydraulic chamber O is overwhelmingly large, and the spool is switched to the left to reach the valve position shown in FIG.

In FIG. 5, the hydraulic oil discharged from the hydraulic pump 5 reaches the port J of the hydraulic cylinder 1 through the ports P, A, C, and E, flows into the rod-side oil chamber 4 and flows into the piston 2. Press. The hydraulic oil in the head side oil chamber 3 returns from the port K to the tank 15 via the check valve 12 and the ports F, D, B and T. As a result, the hydraulic cylinder 1 is contracted to separate the rocking plate 25 of the crusher built-in bucket 20 from the fixed wall 23 and discharge the fine particles 56 between the fixed wall 23 and the rocking plate 25 downward. .

In this reduction stroke, the rocking plate 25 stops when the hydraulic cylinder 1 contracts to the end of the stroke or when foreign matter is entrained in the middle of the stroke, and the flow of the hydraulic oil in the main circuit stops. The pressure in the passage ELUJ rises above the maximum working pressure of the relief valve 9. Due to this increase in pressure, the relief valve 9 of the branch passage L pushes the spring 19 to perform oil discharge operation, and hydraulic oil flows into the pilot hydraulic chamber N of the direction control valve 7 from the port M. The thrust of No. 17 pushes the spool of the directional control valve 7 rightward.

At this time, the pilot hydraulic chamber O on the opposite side is connected from the ports F, D, B, and T to the tank 1 via the line OV, the check valve 11 with back pressure regulation, and the line GF. It leads to 5. When the spool of the automatic switching valve 17 moves to the right, the elasticity of the spring 18 of the check valve 11 with back pressure regulation acts on the hydraulic oil in the pilot hydraulic chamber O. Since the pressure is set only slightly higher, the spool easily switches rightward when the pressure acting on the pilot hydraulic chamber N from the port M is sufficiently high. As a result, the control circuit returns to the valve position of FIG.

As described above, the hydraulic cylinder 1 changes to the extension operation, the rocking plate 25 approaches the fixed wall 23, and the object lowered between the fixed wall 23 and the rocking plate 25 in the previous step. 55, and a series of such operations are repeated. If the caught foreign matter is hard and cannot be crushed, the bucket 20 may be turned downward by operating the hydraulic shovel and the foreign matter may be discharged together with the contents.

The control circuit shown in FIG. 1 replaces the circuit configuration having the relief valve 9 on the left side of FIG. 3 with the circuit configuration having the automatic switching valve 8 on the right side of FIG. That is, a circuit having an automatic switching valve 8 is symmetrically arranged in two main pipelines connecting the directional control valve 7 and the hydraulic cylinder 1 to realize the same function and effect as the circuit of FIG. I have.

In FIG. 1, hydraulic oil discharged from the rod-side oil chamber 4 when the hydraulic cylinder 1 is extended extends from a port J through a check valve 12 ′, and through ports E, D, B and T to a tank. Return to 15. The hydraulic oil discharged from the head-side oil chamber 3 when the hydraulic cylinder 1 is contracted, passes through the check valve 12 from the port K, and returns to the tank 15 through the ports F, D, B, and T. When the direction control valve 7 switches to the left, the hydraulic oil in the pilot hydraulic chamber N passes through the check valve 11 ′ with back pressure regulation, and returns to the tank 15 via the ports E, D, B, and T. When the direction control valve 7 is switched to the right, the hydraulic oil in the pilot hydraulic chamber O passes through the check valve 11 with back pressure regulation, and returns to the tank 15 via the ports F, D, B, and T.

The control circuit of FIG. 2 replaces the circuit configuration having the automatic switching valve 8 on the right side of FIG. 3 with the circuit configuration having the relief valve 9 on the left side of FIG. That is, a circuit having a relief valve 9 is symmetrically arranged in two main pipelines connecting the directional control valve 7 and the hydraulic cylinder 1 to realize the same function and effect as the circuit of FIG. You. In this control circuit, the check valve 13 corresponds to the check valve 13 ′ with back pressure regulation, and its spring resilience is set to be slightly stronger than that of the spring 17 of the direction control valve 7. When the hydraulic cylinder 1 is contracted, a constant pressure in the pilot hydraulic chamber O is maintained to prevent the spool from naturally switching rightward due to the elasticity of the spring 17 of the directional control valve 7.

In FIG. 2, the hydraulic oil flowing into the head-side oil chamber 3 when the hydraulic cylinder 1 is extended extends through the pipe FU-U′-L′-K to push out the piston 2. When the extension operation of the hydraulic cylinder 1 is stopped, the relief valve 9 ′ performs a drainage operation, and this hydraulic oil flows into the pilot hydraulic chamber O of the directional control valve 7 to move the spool of the directional control valve to the left. Press Further, when the hydraulic cylinder 1 is contracted, the hydraulic oil flows into the rod-side oil chamber 4 of the hydraulic cylinder through the line ULJ. When the contraction operation of the hydraulic cylinder 1 stops, the hydraulic oil discharged from the relief valve 9 flows into the pilot hydraulic chamber N and pushes the spool to the right, and the hydraulic oil in the pilot hydraulic chamber O has a back pressure regulation. It returns to the tank 15 through the check valve 13 '.

[0048]

[Effect of the invention]

 The interlocking control circuit according to the present invention is different from the conventional system in which the forward / backward movement of the hydraulic cylinder is reversed at the stroke end position as in the case of a conventional jaw crusher.If the hydraulic cylinder piston stops due to overload, the forward / backward movement is automatically performed. This is a mechanism for reversing. If this control circuit is incorporated into, for example, a crusher built-in bucket, the control circuit is cut at that position even if the rocker plate is caught by a foreign object such as a block of concrete or rock that is difficult to crush at any position while moving back and forth. Instead, the rotation of the rocking plate is automatically reversed. For this reason, the rocking plate does not remain stopped, and the repeated movement of the rocking plate toward and away from the fixed wall is repeated several times. Even if the foreign material is stopped in the device without being crushed, it can be discharged by turning the bucket downward. Therefore, the rocking plate does not stop during the crushing work, and the work can be continued while always maintaining a constant crushing force, so that the work efficiency is higher than that of the conventional jaw crusher.

The interlocking control circuit according to the present invention is a system in which the automatic changeover valve is directly operated by the pilot pressure by self-detecting the pressure change of the hydraulic oil, and is provided with a changeover switch, a limit switch, a solenoid valve, and a control panel. There is no need to install electrical equipment. If this control circuit is incorporated in a crusher built-in bucket and the bucket is mounted on a hydraulic excavator, it is not necessary to supply a control power supply or the like, and no additional equipment such as cables is required.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram showing a control circuit according to the present invention.

FIG. 2 is a hydraulic circuit diagram showing another embodiment of the present invention.

FIG. 3 is a hydraulic circuit diagram showing still another embodiment of the present invention.

FIG. 4 is a circuit diagram showing a state at the time of an extension operation of a hydraulic cylinder in the circuit of FIG. 3;

FIG. 5 is a circuit diagram showing a state of the circuit of FIG. 3 at the time of a hydraulic cylinder reducing operation.

FIG. 6 shows a bucket with a built-in crusher to which the present invention is applied.
It is the longitudinal cross-sectional view cut | disconnected along the XX line of FIG.

FIG. 7 is a plan view of the bucket shown in FIG. 6;

8 is a side view showing the state of the crushing operation of the bucket shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic cylinder 3 Head side oil chamber 4 Rod side oil chamber 7 Direction control valve 8 Automatic switching valve 9 Relief valve 10 Check valve 11 Check valve with back pressure regulation 12 Check valve 14 Restrictor 16, 17 Spring 20 Built-in crusher bucket

Claims (5)

[Utility model registration claims] A directional control valve is provided at two positions on two main pipelines connected to a rod side and a head side oil chamber of a hydraulic cylinder, and a directional control valve is provided between the rod side and / or the head side oil chamber and the directional control valve. An automatic switching valve is interposed between the automatic switching valve and the automatic switching valve is set to be in the non-operating position in a no-load state. When the hydraulic oil is pumped into the rod side or head side oil chamber and the hydraulic cylinder piston stops and the hydraulic oil inflow side pressure in the rod side or head side oil chamber rises, the pilot pressure deactivates the automatic switching valve. An interlocking control circuit that switches to the position and switches the direction control valve to the opposite position. 2. A two-way directional control valve is provided in two main pipelines connected to a rod side and a head side oil chamber of a hydraulic cylinder, and a directional control valve is provided between the rod side and / or head side oil chamber and the directional control valve. Hydraulic oil flows through the branch passage through the relief valve and the check valve to return to the main pipeline near the directional control valve, the piston of the hydraulic cylinder stops, and the rod side or head side oil chamber is provided. When the hydraulic oil inflow side pressure rises, the relief valve operates and the directional control valve is switched to the opposite position by the discharged oil. 3. A hydraulic cylinder housed in a bucket frame, and a rocking plate rotatably mounted near a rear opening of the bucket frame and approaching / separating from a bucket fixing wall by expansion / contraction operation of the hydraulic cylinder. And two main pipelines connected to a rod side and a head side oil chamber of a hydraulic cylinder in a bucket with a built-in crusher having a bracket portion provided with a pin hole for mounting on a work cart arm such as a hydraulic shovel. A directional control valve at two positions, and an automatic switching valve is interposed between the directional control valve and the rod-side and / or head-side oil chambers. Set to the non-operating position, and for the automatic switching valve,
The input port is the output port of the directional control valve, the one output port is the port of the rod-side oil chamber or the head-side oil chamber of the hydraulic cylinder, and the other output port is the throttle, check valve, and non-return valve with back pressure regulation. Each of them communicates with its own input port through a pipe line provided with a valve, and allows only the flow from the other output port of the automatic switching valve to the input port while allowing the pilot pressure from one output port to flow. Acts on the spool of the automatic switching valve in the same direction as the spring pressure, the pilot pressure from the input port acts on the spool of the automatic switching valve in the opposite direction to the spring pressure, and the pipe has a check valve and back pressure regulation. The pilot pressure between the check valve and the directional control valve acts on the spool of the directional control valve, and further, a return path from the port of the rod side oil chamber or the head side oil chamber of the hydraulic cylinder to the input port of the directional control valve. When hydraulic oil flows from the directional control valve to the automatic switching valve by interposing the check valve, the automatic switching valve is switched to the operation position by the pilot pressure, and the hydraulic oil is sent to the rod-side or head-side oil chamber, and the excess oil is discharged. When the swing plate stops rotating due to the load, the piston of the hydraulic cylinder stops, and the hydraulic oil inflow side pressure in the rod-side or head-side oil chamber increases, the pilot switching pressure switches the automatic switching valve to the non-operating position. The control circuit of the crusher built-in bucket that switches the direction control valve to the opposite position. 4. A hydraulic cylinder housed in a bucket frame, and a rocking plate rotatably mounted near a rear opening of the bucket frame and approaching / separating from a bucket fixing wall by expansion / contraction operation of the hydraulic cylinder. And two main pipelines connected to a rod side and a head side oil chamber of a hydraulic cylinder in a bucket with a built-in crusher having a bracket portion provided with a pin hole for mounting on a work cart arm such as a hydraulic shovel. A directional control valve at two positions and a branch passage between the directional control valve and the rod-side and / or head-side oil chamber, and the branch passage is configured to perform oil discharge operation at the maximum operating pressure of the hydraulic cylinder. The flow of the hydraulic oil is allowed to return to the main line near the directional control valve via the valve and the check valve, and the pilot pressure between the relief valve and the check valve in the branch path is controlled by the directional control valve. When the swing plate stops rotating due to overload, the piston of the hydraulic cylinder stops and the hydraulic oil inflow pressure in the rod-side or head-side oil chamber rises, causing the relief valve to operate. The crusher built-in bucket control circuit switches the directional control valve to the opposite position by the discharged oil. 5. A circuit provided with an automatic switching valve according to claim 3 in one of the main pipelines, for two main pipelines connected to a rod side of a hydraulic cylinder, a head side oil chamber, and a directional control valve at two positions. The control circuit according to claim 3, wherein a circuit provided with the relief valve according to claim 4 is installed on the other of the main lines.