JPH0592895A - Lift operating valve lever operating device - Google Patents

Abstract

PURPOSE:To provide an operating device for automatically operating the lift operating hydraulic switching valve of a forklift using an actuator while allowing cargo handling means such as a fork to be positioned at the specified height. CONSTITUTION:There are provided a clevis 8 protruding from a lift operating valve lever 2 for a hydraulic switching valve switched manually and having a pin around its tip part, and a motor-driven cylinder 10 with its body side rotatably supported on a valve fitting plate 15. Two plate springs 16A, 16B are rigidly fixed to the tip part of the rod 12 of the motor-driven cylinder 10 in such a way as to hold the rod tip part in the mutually opposed state and to bend at an appropriate angle at the tip part thereof so as to come in contact with each other, and a pin 9 provided at the clevis 8 is inserted with play into a space between two plate springs 16A, 16B to form a lift operating valve lever operating device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operating device for a lift operating valve lever, and more particularly to an automatic operation of a hydraulic switching valve for operating a lift of a forklift by using an actuator so that a fork or the like is moved to a predetermined height. The present invention relates to a device that can be suitably adopted for an automatic lift that can position the cargo handling tool.

[0002]

2. Description of the Related Art Conventionally, there has been proposed an automatic lift device for a forklift having an automatic lift function for raising a fork to a preset lift. This device
A method in which a solenoid valve is attached separately from a manual hydraulic pressure switching valve and the hydraulic pressure is controlled by the manual valve during normal manual operation and by the solenoid valve during automatic lift is used.

This device will be described with reference to FIG. 8. When manually raising the fork 18, the lift operation valve lever 2 is operated to switch the hydraulic pressure switching valve 1 to the port P1. From the above, pressure oil is supplied to the bottom side of the lift cylinder 17 through the solenoid valve S and the check valve C1 by the pump P which is rotationally driven by the motor M, and the fork 18 rises.

When the automatic lift is used, the pump P can be rotationally driven by pressing the automatic lift switch AS, the solenoid valve S is switched to the port P3, and the lift cylinder 17 is passed through the check valve C2. Is supplied to the bottom side of the fork 18 to raise the fork 18. Furthermore, the limit switch LS fixed to the mast etc.
When it is detected that the fork 18 has reached an arbitrary lifting height, the pump P can be stopped and the solenoid valve S is switched to the port 4, so that the fork 18 can be stopped.
The lift will stop. In the case of the automatic lift, the hydraulic pressure switching valve 1 remains in the neutral position.

[0005]

However, in the structure in which the solenoid valve S is mounted separately from the manual hydraulic switching valve 1, a hydraulic system for automatic lift only is added in parallel to the manual hydraulic system. become. Therefore, as shown by the chain line in FIG. 8, not only the solenoid valve S, but also a relief valve R2, a check valve C2, a plate for mounting them, hydraulic pipes, blocks, and other expensive and large-sized parts must be added. In addition to this, there is a problem that piping work increases and assembly takes time. Further, since the hydraulic operation by the solenoid valve S is abruptly performed, there is a problem that a shock is great when the lift is started and stopped, and the load on the fork 18 is easily collapsed. The present invention has been devised in view of the above circumstances, and an object thereof is to provide an automatic lift device for a forklift truck that can realize an automatic lift function at an extremely low cost and that can reduce shock when starting and stopping the lift. There is something to do.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a clevis projecting from a lift operating valve lever of a hydraulic switching valve that is manually switched and a pin is provided near a tip, and a main body side is a valve mounting plate. An electric cylinder rotatably supported is provided, and rod end portions of the electric cylinder are fixed so as to face each other so as to sandwich the rod end portion, and the end portions are bent at an appropriate angle and contact each other. This is a device for operating a lift control valve lever in which a leaf spring is fixed and a pin provided on the clevis is loosely fitted and inserted into a space between the two leaf springs.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to FIG. 1 which is a perspective view showing the structure of the present invention. The present invention relates to a lift operation valve lever (hereinafter, simply referred to as a lift lever) 2
A clevis 8 having a pin 9 is projectingly formed on the
Is loosely fitted and inserted into a space formed by two leaf springs 16A and 16B fixed to the tip of the rod 12 of the electric cylinder 10.

A boss 2A fixed to the lower end of the lift lever 2 is tiltably supported by a shaft 5 fixed to a valve mounting plate 15. An arm 6 is formed on the boss, and the tip end of the arm 6 is
It is connected to the valve plunger 7 of the hydraulic pressure switching valve 1. Therefore, it is well known that the valve plunger 7 can be moved up and down by the tilting operation of the lift lever 2 to switch the direction of hydraulic pressure and adjust the flow rate.
When the lift lever 2 is released, the lift lever 2 returns to the neutral state by the return spring (not shown) inserted in the valve plunger 7. Further, 3 and 4 are levers for other cargo handling operations such as tilt and reach, respectively.

The clevis 8 is formed so as to project from the boss portion 2A of the lift lever 2 to a predetermined length, and a pin 9 is provided near the tip thereof.

The electric cylinder 10 has a bracket 13 fixed to the lower end of the main body 11, and is rotatably supported by the valve mounting plate 15 by a pin 14. Further, the electric cylinder 10 normally keeps its rod 12 extended, and when an automatic lift switch (not shown) is turned on,
The rod 12 is configured to contract, and when the fork 18 reaches a predetermined lift, the rod 12 can be extended again.

A leaf spring 16 is provided at the tip of the rod 12 so as to face each other and sandwich the tip of the rod 12.
A and 16B are fixed, and the pin 9 of the clevis 8 is loosely fitted and inserted into the space of both. Therefore, the electric cylinder 1
0 is a leaf spring 16 fixed to the tip of the rod 12.
A and 16B contact the clevis 8 and the standing state is maintained.

It should be noted that the leaf springs 16A and 16B each have their tip portions bent at an appropriate angle in the respective directions,
In addition, they are kept in contact with each other.

[0013]

The operation of the present invention configured as described above will be described with reference to FIGS. 2 to 7 showing the relationship between the lift lever 2 and the fork 18.

FIG. 2 shows the case where the lift lever 2 is in the neutral position, and for convenience of explanation, it is assumed that the fork 18 is also in the lowest position. In this state, the electric cylinder 10
Has the rod 12 extended.

Next, in FIG. 3, the fork 18 is manually operated.
The operation of the ascending operation (hereinafter referred to as lift-up) is shown. When the lift lever 2 is tilted in the direction of arrow A, the valve plunger 7 is pulled up as described above, and the pressure oil is supplied to the lift cylinder 17. The fork 18 can be raised. When the lift lever 2 is released, it returns to neutral and the fork 18 stops rising.

Further, FIG. 4 shows the lowering operation of the fork 18 (hereinafter referred to as lift down). When the lift lever 2 is tilted in the direction of arrow B, the valve plunger 7 is pushed down and the lift cylinder 17 moves. The pressure oil is discharged, and the fork 18 can be lowered.

Therefore, during manual operation, the rod 12 of the electric cylinder 10 remains stationary in a fully extended state regardless of whether it is lifted up or down, and the pin 9 of the clevis 8 is moved even if the lift lever 2 is moved back and forth. Only moves freely in the space formed between the two leaf springs 16A16B, and the hydraulic switching valve can be manually operated without any influence on the electric cylinder 10.

Next, the automatic lift will be described with reference to FIG. The automatic lift, for example, matches the lift of the fork 18 with the height of the shelf 20 which is known in advance.
In this example, a shelf height L1 is assumed, and a limit switch LS is provided on a mast (not shown) so that the height of the fork 18 can be detected.

The driver operates an automatic lift switch (not shown)
When is pressed, the rod 12 of the electric cylinder 10 contracts, and two leaf springs 16A fixed to the tip of the rod 12 are
The action of pulling down the pin 9 of the clevis 8 is obtained by 16B. As a result, the lift lever 2 is tilted in the direction of the arrow A as in the manual lift-up, and the lift-up can be performed. Further, the limit switch LS detects that the fork 18 has reached the lifting height L1, and based on the detection signal, the rod of the electric cylinder 10 is extended, the lift lever 2 is returned to the neutral position, and the lift-up is stopped. To do.

Further, in the automatic lift state, if the rod 12 of the electric cylinder 10 remains immobile for some reason and remains immobile, the fork 18 will continue to rise even if it exceeds an arbitrary lift L1. , Very dangerous. In such a case, the driver strongly tilts the lift lever 2 in the direction of arrow B, so that
As shown in FIG. 6, even when the rod 12 of the electric cylinder 10 is in a contracted state, the pin 9 of the clevis 8 spreads out the space between the two leaf springs 16A and 16B, and the electric cylinder 10 and the clevis 8 Can be disconnected. As a result, the electric cylinder 10 with the lift lever 2 locked
, And normal manual operation becomes possible.

The main body 11 of the electric cylinder 10 is rotatably supported by the pin 14 as described above. Therefore, when the electric cylinder 10 and the clevis 8 are disconnected, the electric cylinder 10 is electrically driven. Cylinder 10 is centered around pin 14
Since it rotates 0 degree and falls downward, it does not hinder the operation of the lift lever 2. Further, when the electric cylinder is stuck in the extended state, the automatic lift cannot be used, but normal manual operation is possible.

Further, the pair of leaf springs 16A and 16B are
It goes without saying that the spring constant can be arbitrarily selected and variously adopted so that the force required to tilt the lift lever 2 can be generated at the contact portion of the leaf springs 16A and 16B.

[0023]

As a result of adopting the above-described structure, the present invention can realize a lift lever operating device having an automatic lift function by adding a small number of parts without any modification to the hydraulic circuit. Further, since the hydraulic operation of the present invention is a method of operating a manual hydraulic switching valve, which is usually operated by a human, by an electric cylinder, it is possible to greatly reduce the shock caused by switching the solenoid valve as in the conventional case. It is possible to effectively prevent collapse of the upper load. Further, even when the electric cylinder used does not move due to a failure or the like, the electric cylinder and the lift lever can be easily separated, so that the cargo handling work by the manual operation can be secured.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of the present invention.

FIG. 2 is a diagram for explaining the operation of the present invention.

FIG. 3 is a diagram for explaining the operation of the present invention.

FIG. 4 is a diagram for explaining the operation of the present invention.

FIG. 5 is a diagram for explaining the operation of the present invention.

FIG. 6 is a diagram for explaining the operation of the present invention.

FIG. 7 is a diagram for explaining the operation of the present invention.

FIG. 8 is a hydraulic circuit diagram of a conventional automatic lift device.

[Explanation of symbols]

 1 Hydraulic Switching Valve 2 Lift Operation Valve Lever 5 Shaft 8 Clevis 9 Pin 10 Electric Cylinder 11 Main Body 12 Rod 16A Leaf Spring 16B Leaf Spring 17 Lift Cylinder 18 Fork

Claims (1)

[Claims] 1. A clevis that projects from a lift operating valve lever of a hydraulic switching valve that is manually switched and has a pin near its tip, and a main body side rotatably supported by a valve mounting plate. An electric cylinder is provided, and two leaf springs are fixed to the rod tip of the electric cylinder so as to face each other so as to sandwich the rod tip and the tip bends at an appropriate angle and comes into contact with each other. ,
A lift operating valve lever operating device in which a pin provided on the clevis is loosely fitted and inserted into a space between the two leaf springs.