JP2687825B2 - Bucket attachment / detachment device control circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a control circuit for a bucket attaching / detaching device equipped on a construction machine such as a hydraulic excavator.

[0002]

2. Description of the Related Art FIG. 7 is a side view of a hydraulic excavator.
In the drawing, reference numeral 1 denotes a work attachment mounted on a front part of a hydraulic shovel, and 2 denotes a work attachment 1.
, 3 is an arm, 4 is a bucket, 5 is a bucket link, 6 is an idler link, 7 is a bracket erected on the back of the bucket 4, and 8 and 9 are connecting pins. FIG. 8 is a sectional view taken along the line AA of FIG. In the figure, 10 is an arm tip boss of the arm 3, 11 is a bucket link tip boss of the bucket link 5, 12 is an arm tip mounting pin hole drilled in the bracket 7, 13 is a bucket link tip mounting pin hole, Reference numerals 14 and 15 are locking portions when the pins 8 and 9 are pivoted.

As shown in FIGS. 7 and 8, in the bucket attaching / detaching device of the prior art, a bracket 7 is erected on the back surface of the bucket 4, and the arm tip mounting pin hole 12 and the bucket link tip mounting portion are mounted on the bracket 7. The pin holes 13 are opened in parallel with each other, and the tip of the arm 3 and the tip of the bucket link 5 of the work attachment 1 and the bracket 7 of the bucket 4 are attached and detached via the pins 8 and 9.

[0004]

In the hydraulic excavator, the buckets are frequently replaced depending on the type of work, work content or work situation. In the prior art shown in FIGS. 7 and 8, since the pins are pivotally attached to the tip ends of the arm and the bucket link and the bracket of the bucket, the driver or the operator pulls out the pins to replace the bucket. Was going on. Therefore, it takes a lot of labor and time to replace the bucket, and the work efficiency is lowered. In view of this, various bucket attaching / detaching devices have been considered in which the bucket replacement operation can be performed easily and in a short time. An object of the present invention is to provide a control circuit for the bucket attaching / detaching device.

[0005]

According to the control circuit of the bucket attaching / detaching device of the present invention, the respective pipe lines leading to the spring chambers inside the bucket link tip boss and inside the arm tip boss are
First and second electromagnetic switching valves capable of switching between a hydraulic pressure source and an oil tank are provided respectively, and piston pin oil chambers inside the bucket link tip boss and arm tip boss are communicated via a pipe line, The communication line is provided with a third electromagnetic switching valve capable of switching between a hydraulic source and an oil tank,
When all the first, second, and third electromagnetic switching valves are energized by a switch operation, all piston pins are retracted, and the first and third electromagnetic switching valves are energized and the second electromagnetic switching valve is energized. When the switching valve is de-energized, the piston pin inside the bucket link tip boss pulls in, and the piston pin inside the arm tip boss projects, and all the first, second, and third electromagnetic switching valves All piston pins are configured so as to perform a projecting operation when is de-energized.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing a cross section of a bucket attaching / detaching device of the present invention and a hydraulic circuit for operating the bucket attaching / detaching device. In the figure, the same reference numerals are given to components using the same components as the conventional technology. Reference numeral 16 denotes a boss portion for the arm tip end mounting pin hole 12 fixed to the inner surface side of the bracket 7 of the bucket 4 facing the bracket 7, 17 for the bucket link tip end mounting pin hole 13, and 18 for the arm. A tip boss, 19 is a bucket link tip boss, 20 is a piston pin fitted into both left and right ends of the arm tip boss 18 and the bucket link tip boss 19, 21 is a bush, 22 is a seal member, and 23 is an O ring. 24 is a seal member fitted to the outer periphery of the base of the piston pin 20, 25 and 25 'are spring chambers inside the bosses 18 and 19, 26 are springs, 27 and 27' are piston pin oil chambers, respectively. 28 is a stopper portion of the piston pin 20,
29L and 29R are hydraulic ports that are opened in the arm tip boss 18 and communicate with the left and right piston pin oil chambers 27.
0L and 30R are hydraulic ports that are opened in the bucket link tip boss 19 and communicate with the left and right piston pin oil chambers 27 ', and 31 and 31' communicate with the spring chambers 25 and 25 'of the bosses 18 and 19, respectively. Hydraulic ports, 32 is a frame, 33L and 33R are left and right plates of the frame 32, 3
4 is a central connecting plate, 35, 36 and 37 are first, second and third electromagnetic switching valves respectively, 38, 39 and 40 are solenoids of the electromagnetic switching valves 35, 36 and 37 respectively, 41 is a hydraulic power source, 42 Is an oil tank. Since the bucket 4 is used after being inverted and replaced for the excavating operation and the loading operation, the inner diameters of the pin hole 12 for attaching the tip of the arm and the pin hole 13 for attaching the tip of the bucket link are set to the same size φd. Therefore, the diameter of the piston pin 20 is set to be the same as the diameter (φd) of both the pin holes 12 and 13, and the both bosses 18 and 19 are connected to the frame 32 so that both the bosses 18 and 19 are connected.
Is set to the same size as the hole-center distance between the pin holes 12 and 13 of the bucket 4 (dimension p shown in FIG. 1). 2 and 3 are views showing respective working examples of the bucket attaching / detaching device in FIG.

FIG. 4 shows an electromagnetic switching valve (35,
36, 37) is an electric circuit diagram for switching. In the figure,
43 is a changeover switch, 44 is a power supply, 45 is a relay, 4
6, to 49 are diodes, and 50 is a fuse. FIG. 5 is a plan view of the bucket attaching / detaching device of the present invention. In the figure, 51L and 51R are positioning guide plates fixed to the outer surfaces of the left and right plates 33L and 33R of the frame 32, respectively. FIG. 6 is a side view of the bucket attaching / detaching device of the present invention seen from B of FIG.

Next, the configuration of the control circuit of the present invention will be described with reference to FIGS. In the present invention, the spring chamber 25 ′ inside the bucket link tip boss (19) and the arm tip boss (1
8) A first electromagnetic switching valve 35 and a second electromagnetic switching valve 36 that can switch the respective pipelines 52, 53 communicating with the internal spring chamber 25 with respect to the hydraulic pressure source 41 and the oil tank 42 are provided, respectively, and a bucket. The piston pin oil chamber 27 'inside the link tip boss (19) and the piston pin oil chamber 27 inside the arm tip boss (18) are communicated with each other through a conduit, and the communicating conduit is connected to the hydraulic source 41. Third that can be switched to the oil tank 42
The electromagnetic switching valve 37 is provided, and the piston pin 20 is retracted and ejected by operating the switch (43).

Next, the operation of the control circuit of the present invention will be described. First, when the removed bucket (4) is attached to the tip of the work attachment, the rotary switch 43 is operated to the contact a as shown in FIG. Power 44
The current from flows to the solenoid 39 via the switch 43 and to the relay 45 via the diode 46. Since the relay 45 operates and the electric current also flows through the solenoids 38 and 49, all the solenoids 38, 39,
40 is energized. Therefore, the electromagnetic switching valves 35, 36, 3
The switching positions of 7 are the b position, the c position, and the d position, respectively, as shown in FIG. In this case, the spring chambers 31, 3
1 ′ communicates with the oil tank 42 via the tank communication oil passage positions B and C of the electromagnetic switching valves 35 and 36, respectively. Therefore, the pressure oil from the hydraulic power source 41 passes through the opening oil passage position D of the electromagnetic switching valve 37 and the pipe passage 54, one passage through the pipe passages 55, 56L and 56R, and the ports 29L and 29R, and then the left and right piston pin oil chambers 27. , 27, and branched at the pipe 54, and the other is sent to the left and right piston pin oil chambers 27 ', 27' through the pipes 57, 58L, 58R and the ports 30L, 30R. As a result, all piston pins 20 have springs 2
6 Pulls inward against the spring force. Then, since the tips of all the piston pins 20 are drawn inward from the left and right outer side surfaces of the frame body 32, the driver operates the work attachment of the hydraulic excavator to operate the boss portions 16 and the opposing boss portions 16 of the bracket 7 of the bucket 4. The frame 3 is provided on the inner surface side of each of 17
Insert the outer surface side of 2. At the same time, the guide surfaces 59 of the positioning guide plates 51L and 51R fixedly provided on the left and right of the frame body 32 come into contact with the upper outer peripheral surfaces of the boss portions 16 and 17 of the bucket 4 bracket 7. When operated in this state, the shaft centers of the piston pins 20 of both bosses 18 and 19 and the hole centers of both pin holes 12 and 13 of the bracket 7 of the bucket 4 can be aligned.

As described above, all piston pins 2
0 is pulled inward from both the left and right outer side surfaces of the frame body 32, and the axial center of the piston pin 20 and the pin centers of both pin holes 12 and 13 of the bracket 7 of the bucket 4 are aligned. The switch 43 (shown in FIG. 4) is operated to the contact b. The relay 45 is operating and the solenoids 38 and 40 are energized, but the solenoid 39 is de-energized. In this case, as shown in FIG. 2, the electromagnetic switching valves 35 and 37 remain at the low position and the double position, respectively, but the electromagnetic switching valve 36 switches to the tank communication oil passage position E. The spring chamber 25 'inside the bucket link tip boss 19 communicates with the oil tank 42 via the position b of the electromagnetic switching valve 35, and the piston pin oil chamber 27' is hydraulically operated via the position two of the electromagnetic switching valve 37. Source 41
, The piston pin 20 inside the bucket link tip boss 19 remains in the retracted state. On the other hand, the oil pressure from the hydraulic pressure source 41 acts on the piston pin oil chamber 27 inside the arm tip boss 18 via the two positions of the electromagnetic switching valve 37, but at the same time, the same hydraulic pressure from the hydraulic pressure source 41 is applied. It acts on the spring chamber 25 through the E position of the electromagnetic switching valve 36, the conduit 53, and the port 31. Therefore, the piston pin 20 inside the arm tip boss interior 18 is caused to project outward due to the pressure due to the piston pin pressure receiving area difference and the spring force. Then, the protruding tip side of the piston pin 20 is
It can be fitted into the pin hole 12 of the bucket 4.

When the piston pin 20 on the arm tip boss 18 side is fitted into the pin hole 12 of the bucket 4 as described above, the switch 43 is next operated to the contact C. Since the contact C has no conduction circuit, all the solenoids 38,
39 and 40 are not energized. Therefore, the electromagnetic switching valve 3
As shown in FIG. 3, the switching positions of 5, 36, and 37 are the F position, the E position, and the G position, respectively. In this case, all of the piston pin oil chambers 27 and 27 'are connected to the electromagnetic switching valve 37.
However, since the hydraulic pressure from the hydraulic pressure source 41 is acting on the spring chamber 25 inside the arm tip boss 18 via the E position of the electromagnetic switching valve 36, the arm tip boss 18 is connected to the oil tank 42. The piston pin 20 on the 18 side is still in the pin hole 12 of the bucket 4. At the same time, the pressure oil from the hydraulic pressure source 41 acts on the spring chamber 25 ′ through the position of the electromagnetic switching valve 35, the pipe line 52, and the port 31 ′. Therefore, the piston pin 20 inside the bucket link tip boss 19 is projected outward, and the tip side thereof can be fitted into the pin hole 13 of the bucket 4. Thereby, the bucket 4 can be attached to the work attachment.

As described above, the switch 43 can be operated in sequence in the three stages of the contacts a, b, c to surely and easily attach the bucket 4 to the tip of the work attachment. When removing the attached bucket 4, the reverse operation to the above-mentioned attachment may be performed.

[0013]

According to the control circuit of the bucket attaching / detaching device of the present invention, each of the pipelines leading to the spring chambers inside the bucket link tip boss and the arm tip boss can be switched between a hydraulic power source and an oil tank. A second electromagnetic switching valve is provided, and the piston pin oil chambers inside the bucket link tip boss and the arm tip boss are communicated with each other through a pipeline, and the communication pipeline is connected to a hydraulic source and an oil tank. A third electromagnetic switching valve that can be switched over is provided, and the above three electromagnetic switching valves are switched by a switch operation so that the bucket is detached. That is, when the first, second, and third electromagnetic switching valves are energized as the first-stage switch operation, all piston pins are retracted, and then the second-stage switch operation is performed. When the third solenoid directional control valve is energized and the second solenoid directional control valve is de-energized, the piston pin inside the bucket link tip boss performs a retracting operation and the piston pin inside the arm tip boss performs a protruding operation. Then, as a third stage switch operation, when all the first, second, and third electromagnetic switching valves are de-energized, all piston pins perform a projecting operation.
Therefore, the driver can operate the switch at the driver's seat to reliably, easily, and automatically attach / detach the bucket in a short time, so that the operability and workability of the attaching / detaching work can be improved.

[Brief description of the drawings]

FIG. 1 is a view showing a cross section of a bucket attaching / detaching device of the present invention and a hydraulic circuit for operating the bucket attaching / detaching device.

FIG. 2 is a diagram showing an operation example of the bucket attaching / detaching device in FIG.

FIG. 3 is a diagram showing an operation example of the bucket attaching / detaching device in FIG.

4 is an electric circuit diagram for switching the solenoid operated directional control valve in FIG.

FIG. 5 is a plan view of the bucket attaching / detaching device of the present invention.

FIG. 6 is a side view seen from B of FIG.

FIG. 7 is a side view of the hydraulic excavator.

8 is a cross-sectional view showing the conventional technique seen from AA in FIG.

[Explanation of symbols]

 4 Bucket 7 Bracket 10,18 Arm tip boss 11,19 Bucket link tip boss 12,13 Pin hole 20 Piston pin 25,25 'Spring chamber 26 Spring 27,27' Piston pin oil chamber 32 Frame body 35,36,37 Solenoid switching valve 38, 39, 40 Solenoid 41 Hydraulic power source 42 Oil tank 43 Switch

Claims (1)

(57) [Claims] 1. An arm tip mounting pin hole and a bucket link tip mounting pin hole are opened parallel to each other in a bracket on the back surface of the bucket, and left and right inside the boss of the arm tip and the bucket link tip, respectively. And a piston pin that is movable in the axial direction of the boss is provided, and springs are arranged in the spring chambers between the left and right piston pins to urge the piston pins to the outside respectively. By applying hydraulic pressure to the piston pin oil chamber, the piston pin is moved inward against the spring force of the spring, and the arm tip and bucket link tip of the work attachment and the bucket bracket are Is a bucket attaching / detaching device for attaching / detaching via the above-mentioned piston pin. First and second electromagnetic switching valves capable of switching the respective pipelines communicating with the internal spring chambers with respect to the hydraulic source and the oil tank are provided, respectively, and the piston pin inside the bucket link tip boss and the arm tip boss respectively. The oil chamber is communicated via a pipe, and the communication pipe is provided with a third electromagnetic switching valve capable of switching between a hydraulic pressure source and an oil tank. When all the solenoid switching valves are energized, all piston pins are retracted, and when the first and third electromagnetic switching valves are energized and the second electromagnetic switching valves are de-energized, the inside of the bucket link tip boss , The piston pin performs the retracting operation and the piston pin inside the arm tip boss performs the protruding operation,
A control circuit for a bucket attaching / detaching device, wherein all piston pins are caused to project when all the first, second, and third electromagnetic switching valves are de-energized.