JPH0953608A - Slide arm mechanism with lock device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent natural extension of a slide arm caused by leakage of oil by arranging a lock device on a slide arm such as construction machine in which a hydraulic cylinder is utilized. SOLUTION: When an operating pedal 41 is stepped down to a front side, a limit switch is turned on, pressure oil supplied from a hydraulic pump 46 to an oil pressure pipe 36 flows in a port so as to push up the piston rod 30 of a lock cylinder 28 backward. Pressure oil pushed out from an opposite side port flows from the oil pressure pipe 37 to an oil tank 47. A taper piston 31 is pushed in a right direction by the piston rod 30 whose oil flows out, and simultaneously a taper lock pin 22 is pushed down against a spring 26. A lock pin 22a is engaged with a lock stopper 15, and a slide arm 9 is locked. When leg is stepped off from the pedal 41, the piston rod 30 is held in a present position so as to hold a lock condition. When the pedal 41 is stepped down to a rear side, lock is released. It is thus possible to prevent extension of a slide arm caused by leakage of oil.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of construction machines and the like equipped with a slide arm using a hydraulic cylinder.

[0002]

2. Description of the Related Art Conventionally, slide arms utilizing hydraulic cylinders have been used in construction machines such as power shovels. Fig. 7 shows an overall view of the power shovel. In FIG. 1, the traveling vehicle 1 has an upper revolving structure 3 rotatably provided on a lower traveling structure 2. Further, a boom 4 is provided on the upper swing body 3 so as to be swingable in the vertical direction within the plane of the drawing, and an arm 5 is swingably attached to the tip of the boom 4. Boom 4 is boom cylinder 6
The rotation angle is controlled by, and the rotation angle of the arm 5 is controlled by the arm cylinder 7. A slide arm 9 having a bucket 8 at its tip is slidably provided on the upper surface of the arm 5. Expansion and contraction of the slide arm 9 is controlled by a slide arm cylinder 10. The bucket 8 is a bucket cylinder 11
The rotation angle is controlled.

A large load may act on the slide arm cylinder 10 for controlling the slide arm 9 in the moving direction of the cylinder for a long time, and oil leakage is likely to occur. In a conventional hydraulic excavator, an oversized spool is used or a holding valve is attached in order to reduce oil leak in a hydraulic cylinder.

[0004]

However, even if the above-mentioned oversized spool or holding valve is used, it is difficult to reduce the oil leak of the hydraulic cylinder to zero. Therefore, if the slide arm power shovel is used for continuous excavation or long-time hanging work, the slide arm will naturally extend due to oil leaks without the operator's knowledge, and the slide arm will move beyond what the operator thinks. It has been elongated for a long time, and an operation error may occur when moving to the next operation, which may cause a danger due to the malfunction.

The present invention has been made under the background as described above, and an object thereof is to provide a slide arm which prevents natural extension of the slide arm due to oil leak while the operator does not notice.

[0006]

In order to solve the above problems, a lock device is provided on the slide arm to lock the slide arm when a load is applied for a long time. Further, in order to facilitate the lock, the lock is held so as to solve the problem. In addition, the solution is being made by allowing the lock device to be operated from inside the cabin. More specifically, the following means are used to solve the problem.

That is, the device according to claim 1 is intended to be solved by providing a lock device along with a slide arm using a hydraulic cylinder of a construction machine or the like. Further, the device according to claim 2 is a solution to the locking device according to claim 1, in which a holding means for holding and releasing the locked state is provided. Further, the device according to claim 3 is the locking device according to claim 1 or 2, wherein the lock stopper is provided continuously to one of the arm and the slide arm, and the lock stopper provided to the other one. A locking pin that can be engaged and disengaged is used to solve the problem. The apparatus according to claim 4,
The lock device according to claim 3, wherein a taper piston is provided on a piston rod of a hydraulic cylinder that can be operated from the inside of the cabin, and the lock pin is moved in a direction substantially orthogonal to a moving direction of the taper piston, whereby the lock stopper is provided. The solution is achieved by engaging and disengaging. According to a fifth aspect of the present invention, the interlocking portions of the lock stopper and the lock pin of the third or fourth aspect are constituted by triangular columnar protrusions to solve the problem.

Further, the apparatus according to claim 6 is the apparatus according to claim 4.
Alternatively, the holding means of 5 is constituted by a friction means provided between the taper piston and a guide surface for guiding the taper piston, and a pressurizing means for pressing the friction surface at the time of locking to solve the problem. According to a seventh aspect of the invention, in the apparatus according to the sixth aspect, the slide arm is not unlocked unless an external force of a predetermined amount or more acts on the friction means in the direction in which the piston rod is contracted, and
The structure is such that the slide arm cannot be locked unless an external force of a predetermined amount or more acts in the direction in which the piston rod is extended, so that the locking is facilitated and a solution is achieved.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. 1 is a diagram showing an overall outline of Embodiment 1 of the present invention. In FIG. 1, a slide arm 9 is provided above the arm 5.
Is slidably provided. The slide arm 9 is guided by slide guides 18, 18. One end of a slide arm cylinder 10 is attached to the inner central portion of the slide arm 9, and the other end is attached to an attachment member 12 fixedly provided at the rear end of the arm 5. A lock stopper 1 is provided on the rear portion of the upper surface of the arm 5.
5 are continuously arranged. Lock stopper 15
Has a triangular cross section. The cross section of the lock stopper is not limited to a triangle, and for example, a trapezoidal shape, a rectangular shape, or another projection shape may be continuously arranged.

At the rear end of the slide arm 9, there is provided a slide lock device 16 having a lock pin that meshes with the lock stopper 15. Slide lock device 16
As shown in FIG. 2, when the slide arm is retracted and contracted, a part of the is accommodated in the inner space portion 17 of the mounting member 12.

FIG. 3 shows a state in which the slide lock device 16 is not locked. The slide lock device 16 will be described below. In FIG. 3, a frame 21 is fixedly provided below the slide arm 9 at a position close to and above the lock stopper 15. This frame 2
Taper lock pin 2 at the rear end (right end in the figure)
An opening 2 through which the second lock pin 22a can freely move up and down
3 are provided. The rear end of the frame 21 is bent, and the bent portion forms a piston guide portion 34 of the taper piston 31 described later.

A lock pin 22a is provided below the taper lock pin 22, and a taper portion 22b is provided above the lock pin 22a. The lock pin 22a is fitted in the opening 23 so as to be vertically movable. A bush 24 is provided inside the opening 23.
Is fixed. The tip of the lock pin 22a is in the shape of a triangular prism having an inclination of substantially the same angle so as to mesh with the lock stopper 15. A spring 26 is mounted between the lower side of the tapered portion 22b and the frame 21,
In the unlocked state, the lock pin 22b floats upward, and when the tapered portion 22b is pressed downward to lock, the lock pin 22a and the lock stopper 15 are engaged with each other to be in the locked state. In this embodiment, the top of the lock pin 22a is formed as a triangular prism having the same inclination as the lock stopper 15, so that the lock pin 22a can be easily engaged and disengaged. In addition, in order to further facilitate the meshing, the inclination of the top of the lock pin 22a may be a triangular prism having an acute angle with respect to the inclination of the lock stopper 15.

A mounting member 27 is fixed to the frame 21 by welding or the like, and a lock cylinder 28 is mounted to the mounting member 27 by a pin 29. A taper piston 31 is attached to the tip of a cylinder rod 30 of the lock cylinder 28 by a pin 32. A taper having substantially the same inclination angle as the taper portion 22b of the taper lock pin 22 is formed on the lower surface of the taper piston 31. The taper piston 31 is provided above the guide portion 34 of the frame 21 and the lower frame 21.
Is guided by Friction plates 35a and 35b are attached to the surfaces of the guide portion 34 and the tapered piston 31 that are in contact with each other. As for the friction coefficient of the friction plates 35a and 35b, the taper lock pin 22 cannot be actuated downward unless a predetermined force or more acts in the right direction, and the lock is locked by the spring 26 unless a predetermined force or more acts in the left direction. Select so that it will not come off due to the spring force of. It is desirable that the above-mentioned predetermined force is positive and that it is 50% or less of the maximum output.

FIG. 4 shows a state in which the slide lock device 16 is locked. In FIG. 4, when the tapered piston 31 is pushed rearward (to the right in the figure) by the piston rod 30,
The taper of the taper piston 31 generates a force to push the taper portion 22b downward, and overcomes the force of the spring 26 to push the taper lock pin 22 downward. When the taper lock pin 22 is pushed down, the lock pin 22a meshes with the lock stopper 15 and locks the movement of the slide arm 9 in the front-rear direction (left-right direction in the drawing). Further, in this state, when the propulsive force of the piston rod 30 is made zero (released), the spring 26 acts to move the taper piston 31 forward (to the left in the drawing), but the friction plates 35a and 35b. The taper piston 31 does not return to the front (to the left in the figure) due to the frictional force that acts in between. However, when the piston rod 30 is operated to pull the tapered piston forward, the locked state is easily released and the state shown in FIG. 3 is restored. In addition, in order to hold the locked state more completely, the guide portion 34 may be provided with a slight slope and the friction surface may be formed in an upwardly rightward direction.

The lock cylinder 28 has hydraulic pipes 36, 3
7 is connected to a hydraulic control circuit 40 for moving the cylinder rod 30 back and forth (right and left in the figure). FIG. 5 shows the configuration of the hydraulic control circuit. This hydraulic control circuit is provided at a position where it can be easily operated from inside the cabin (driver's cab) of the upper swing body 3 (see FIG. 7). In FIG. 5, limit switches 42a and 42b are connected to the slide arm operation pedal 41. When the operation pedal 31 is depressed to the front side, the limit switch 42
When a is turned on and the rear side is depressed, the limit switch 4
2b is turned on. When the foot is released, the operation pedal 31
Return to the neutral position and the limit switches 42a, 42b
Are both off.

A power supply 43 is connected to the input terminals of the limit switches 42a and 42b by electric wirings 45a and 45b, and the output terminals of the limit switches 42a and 42b are connected to the solenoid valve 4 by electric wirings 45a and 45b.
4 solenoid. Solenoid valve 4
Reference numeral 4 denotes, for example, an electromagnetic 4-port 3-position switching valve. When current flows through the electric wiring 45a, pressure oil from the hydraulic pump 46 is supplied to the hydraulic pipe 36 to the input port of the lock cylinder 28, and the piston rod 30 moves. extend. When a current flows through the electric wiring 45b, pressure oil is supplied to the hydraulic pipe 37,
The piston rod 30 contracts.

A relief valve 50 is branched and connected midway between the solenoid valve 44 and the pipe 48 of the hydraulic pump 46, so that the supplied hydraulic pressure is maintained constant. The other input port of the solenoid valve 44 is connected to the oil tank 47 by a hydraulic pipe 49 via a throttle valve. Further, a display panel (not shown) is provided in the cabin, and when the lock pin 22a is engaged with the lock pin 15, the display panel displays "Lock On",
A display device (not shown) is provided to display "lock / release" when the locked state is released.

The embodiment of the present invention is configured as described above and operates as follows. First, the case where the slide arm 9 is locked will be described. When the operator depresses the operation pedal to the front side in the cabin, the limit switch 42a is turned on, a current flows through the electric wiring 45a, the port of the solenoid 44 is connected to the hydraulic pipe 36, and the hydraulic oil from the hydraulic pump 46 is hydraulically operated. It is supplied to the pipe 36. The pressure oil supplied to the hydraulic pipe 36 is the lock cylinder 2
The piston rod 30 of No. 8 flows into the port so as to be pushed backward. The pressure oil extruded from the port on the opposite side flows through the hydraulic pipe 37, the solenoid valve 44, the throttle 51, and the oil tank 47. The extruded piston rod 30 pushes the taper piston 31 to the right as shown in FIG. 4, and simultaneously pushes the taper lock pin 22 downward against the force of the spring 26. The pushed down lock pin 22a meshes with the lock stopper 15 to lock the slide arm 9. When the lock operation is completed, "Lock On" is displayed on the display panel in the cabin, and the operator releases his / her foot from the operation pedal.

When the foot is released from the operation pedal, both limit switches 42a and 42b are turned off, and the electric wiring 45
No current flows through a and 45b, and the solenoid valve 44 is in a neutral state. No pressure oil is supplied to either of the hydraulic pipes 36 and 37, and the piston rod 30 of the lock cylinder 28 is held at the current position. Further, for example, even if an oil leak occurs and a force for returning the piston rod 30 to some extent is generated, a strong frictional force is generated between the friction plates 35a and 35b, so that the tapered piston 31 is returned. There is no. Therefore, the locked state is maintained.

Next, the operation of unlocking the lock will be described. When the operator depresses the operation pedal 41 to the rear side, the limit switch 42b is turned on, a current flows through the electric wiring 45b, and the solenoid valve 44 switches the connection of the port so as to supply pressure oil to the hydraulic pipe 37. The pressure oil supplied to the hydraulic pipe 37 flows into the port of the lock cylinder 28 that pulls back the piston rod 30, while the pressure oil in the hydraulic pipe 36 is the solenoid valve 4
4. Returning to the oil tank 47 through the throttle 51. Therefore, the rod piston 30 is pulled back forward (leftward) and contracted, and the taper piston 31 is also pulled back by overcoming the frictional force. The taper pin 22 is pulled upward by the spring 26, and the lock pin 22 and the lock stopper 1
The mesh with 5 is disengaged and the lock is released. When the lock is released, "Lock / Unlock" is displayed on the display panel in the cabin.

Then, when the operator releases his / her foot from the operation pedal 41, the limit switches 42a and 42b are turned off, and no current flows through the electric wires 45a and 45b. The solenoid valve 44 is neutralized by the spring force, pressure oil is not supplied to the hydraulic pipes 36, 37, and the lock cylinder 28 is neutralized. Even if a force is generated in the opposite direction due to the oil leak, a reaction force is generated between the friction plates 35a and 35b, so that the piston rod 30 and the taper piston 31 do not move to the right because they overcome the force of the spring 26. Can not. Therefore, the released state is maintained.

As described above, the configuration of the first embodiment has an effect that the expansion and contraction of the slide arm due to an oil leak that may occur while the operator is not aware is prevented, and the danger due to an operation error is eliminated. In addition, the locked state can be easily maintained, and the locking and unlocking operations are facilitated. Further, there is an effect that the slide arm can be locked at an arbitrary position. Also,
Locking and unlocking operations can be performed from inside the cabin, and the operation is easy.

Second Embodiment Hereinafter, the solenoid valve 44 according to the first embodiment will be described as follows.
A second embodiment in which a port 2 position switching valve is used will be described (see FIG. 5). In FIG. 5, the limit switches 42a and 42b are self-hold type limit switches. That is, when the switches 42a and 42b are turned on once, the switches 42a and 42b are kept on until the other switch is turned on, and turned off when the other switch is turned on.
It is a so-called flip-flop type limit switch. Others are the same as those in the first embodiment.

With the above arrangement, one of the limit switches 42a and 42b is always on, and the pressure oil from the hydraulic pump 46 flows into either the hydraulic pipe 36 or 37, There is no longer a situation where the fluid does not flow into either of the 36 and 37. Therefore, the slide arm 9 operates by clearly distinguishing the locked or unlocked state, and the disturbance of the operation due to the disturbance due to the decrease of the hydraulic pressure, the oil leak or the like is reduced. In addition, since a hold mechanism such as a friction plate is provided, even if there is a hydraulic pump failure, the current state (locked state when locked, unlocked state when unlocked) is maintained. The risks that may occur during operation are reduced.

Embodiment 3 FIG. 6 shows another embodiment. The third embodiment is different from the first embodiment in the control circuit. That is, the control circuit 60 is used instead of the control circuit 40. The control circuit 60 will be described below. In FIG. 6, the slide arm operation pedal 6
The limit switch 62 is connected to 1. When the operation pedal 61 is depressed, the limit switch 62 is turned on, and when the operation pedal 61 is released, the limit switch 62 is turned off. A power supply 63 is attached to one end of the limit switch 62.
However, the solenoid of the solenoid valve 64 is connected to the other end by the electric wiring 65. Solenoid valve 6
Reference numeral 4 is, for example, a two-position switching valve. The input port side of the two-position switching valve 64 is connected to a hydraulic pump 66 and an oil tank 67, respectively, by hydraulic pipes. The output port side is connected to the hydraulic pipes 36 and 37. In this connection, when the operation pedal 61 is depressed, a current flows through the solenoid, and the pressure oil from the hydraulic pump 66 is transferred to the hydraulic pipe 3.
7, the pressure oil from the hydraulic pump 66 is supplied to the hydraulic pipe 36 when the operation pedal 61 is released. Further, the hydraulic pipe 36 pushes out the taper piston 31 and locks it so as to lock the cylinder.
It is connected to 28 input ports. The hydraulic pipe 37 is connected to the input port of the lock cylinder 28 so as to retract the taper piston 31 and release the lock.

The third embodiment is configured as described above and operates as follows. When the operation pedal 61 is stepped on during the operation of the power shovel 1, the limit switch 62 is turned on, a solenoid current flows from the power source 63 to the solenoid valve 64 via the wiring 65, and the switching valve port connection is cut off. Replace By this switching, the pressure oil from the hydraulic pump 66 flows into the hydraulic pipe 37, and the return oil from the lock cylinder 28 is returned to the oil tank 67 via the hydraulic pipe 36. As a result, the piston rod 30
The tapered piston 31 that is contracted and is connected to the piston rod 30 overcomes the frictional force between the friction plates 35a and 35b and is attracted. Then, the taper lock pin 22 is lifted by the force of the spring, and the lock is released.

Next, when the foot is released from the operation pedal 61,
The limit switch 62 is turned off, the solenoid current does not flow, and the port connection of the switching valve is switched to the opposite side. As a result, the pressure oil from the hydraulic pump 66 flows into the hydraulic pipe 36, while the return oil passes through the hydraulic pipe 37 and the oil tank 67.
Is returned to. As a result, the piston rod 30 is pushed out, the taper piston 31 is also pushed out, and the taper lock pin 22 is pushed down by overcoming the force of the spring 26. As a result, the lock pin 22a meshes with the lock stopper 15 to lock the slide arm 9.
Further, in this state, when the pressure oil is supplied from the hydraulic pump due to an accident or the like, a frictional force is generated as a drag force between the friction plates 35a and 35b, so that the locked state is held.

As is apparent from the above description, according to the third embodiment, when the driver wants to operate the driver in the unlocked state, the operator depresses the operating pedal, and when the driver wants to lock and operate the vehicle, the operating pedal is released. Well, the driving operation becomes easier. Further, when the slide arm is locked, even if an accident such as a malfunction of the hydraulic pump occurs, the slide arm is held in the locked state by the frictional force of the friction plate. , No danger to operator's work. Although the limit switch 62 is configured to turn on when the operation pedal is depressed and turn off when the foot is released, the limit switch 62 changes from on to off or off to on each time the operation pedal is depressed. A changing limit switch may be used.

Although the embodiments and examples of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to the embodiments and examples, and the design is within the scope of the present invention. Even if there are changes, etc., it is included in this invention.

[0030]

As described above, according to the structure of the present invention, in the invention according to claim 1, the slide arm due to the oil leak of the slide arm cylinder which may occur without the operator being aware. The expansion and contraction of is prevented, and there is an effect that there is no danger of erroneous operation. In the inventions according to claims 2, 6 and 7,
Further, since the locked state can be maintained, the locking operation becomes easy. Particularly, in the invention according to the seventh aspect, the locking operation is automatically performed, so that the locking operation becomes easier. According to the invention described in claim 3, there is an effect that the slide arm can be locked at an arbitrary position and the locking operation becomes easy. According to the invention described in claim 4, there is an effect that the lock operation can be performed from the inside of the cabin, and the operation is further facilitated.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a state in which a slide arm is contracted.

FIG. 3 is a diagram showing a lock device when a lock is released.

FIG. 4 is a diagram showing a lock-on state.

FIG. 5 is a diagram showing an operation circuit for operating the lock device.

FIG. 6 is a diagram showing another operation circuit.

FIG. 7 is a diagram showing a schematic configuration of a power shovel.

[Explanation of symbols]

 5 arm (slide arm mechanism) 9 slide arm (slide arm mechanism) 10 arm cylinder (slide arm mechanism) 15 lock stopper (lock device) 16 slide lock device (lock device) 21 frame 22 taper lock pin 22a lock pin 22b taper piston 26 spring (pressurizing means) 28 lock cylinder (hydraulic cylinder) 30 piston rod 31 taper piston 34 guide part (guide) 35a, 35b friction plate (friction surface) 40, 60 operation circuit

Claims (7)

[Claims] 1. A slide arm mechanism for a construction machine or the like in which a slidable slide arm is provided on the arm and the position of the slide arm is controlled using a hydraulic cylinder,
A slide arm mechanism comprising a lock device provided on the slide arm. 2. The slide arm mechanism for a construction machine or the like according to claim 1, wherein the lock device is provided with a holding means for holding and releasing a locked state. 3. The lock device comprises a lock stopper continuously arranged on one of the arm and the slide arm, and a lock pin which is engageable with and disengageable from the lock stopper provided on the other one. A slide arm mechanism for a construction machine or the like according to claim 1 or 2. 4. The lock device according to claim 1, wherein a taper piston is provided on a piston rod of a hydraulic cylinder that can be operated from the inside of the cabin, and the lock pin is moved in a direction substantially orthogonal to a moving direction of the taper piston to thereby lock the lock device. The slide arm mechanism for a construction machine or the like according to claim 3, wherein the slide arm mechanism engages and disengages with a stopper. 5. The slide arm mechanism for a construction machine or the like according to claim 3, wherein the lock stopper and the lock pin are protrusions each having a triangular prism shape in a mutually engaging portion. 6. The holding means comprises friction means provided between the taper piston and a guide surface for guiding the taper piston, and pressure means for pressing the friction surface when locked. A slide arm mechanism for a construction machine or the like according to claim 4 or 5. 7. The friction means does not unlock the slide arm unless an external force of a predetermined amount or more acts in the direction of contracting the piston rod, and an external force of a predetermined amount or more acts in the direction of extending the piston rod. The slide arm mechanism for a construction machine or the like according to claim 6, wherein the slide arm cannot be locked unless otherwise.