KR100220094B1 - Cargo working control device - Google Patents

Abstract

It is an object of the present invention to provide an unloading control device for a fork lift that can smoothly lower the forks without causing collapse of the cargo at all times.

In order to achieve the above object, the forklift unloading control device of the present invention includes a lift cylinder (4) for elevating the fork (3), a hydraulic pump (8) for distributing pressurized liquid through a pipe to the lift cylinder (4). And a load sensor 21 for detecting the load of the load 32 loaded on the fork 3 and the proportional control valve 7 installed in the pipe connecting the hydraulic pump 8 and the lift cylinder 4 to each other. A lever operating angle detection sensor 22 for outputting a signal corresponding to an operation direction and an operating angle of the lifting operation lever 11, an output of the lever operating angle detection sensor 22. In the fork lowering operation by inputting the controller, a controller 20 is provided to control the hydraulic pump 8 while simultaneously giving a lowering valve opening command proportional to the magnitude of the signal to the proportional control valve 7. The controller 20 is a load detection value of the load sensor 21 exceeds a set value, When the detection signal is in excess of the predetermined value to the detection of the lever operation angle detecting sensor 22 for, it characterized in that it limits the size of the descent valve open command.

Description

Forklift Unloading Control System

1 is a schematic configuration diagram of an unloading control device of a fork lift which is an embodiment of the present invention.

Figure 2 is a graph showing the variation of the gravity acceleration of the cargo during fork lowering of the present invention and the prior art.

3 is a schematic configuration diagram of a conventional forklift unloading control device.

* Explanation of symbols for main parts of the drawings

1: body of the fork lift 14: wheel

2: mast 3: fork

4 lift cylinder 5 valve

6: flow control valve 7: valve (proportional control valve)

8: hydraulic pump 9: motor

10: oil tank 11: lifting operation lever

20: controller 21: load sensor (pressure sensor)

22: Sensor for detecting lever operating angle 30,31: Palette

32: cargo

The present invention relates to an unloading control device of the fork lift.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes a conventional technique with reference to the drawings.

In FIG. 3, 1 is a body of a fork lift which uses a battery as a drive source, 1A is a wheel, 2 is a mast supported by the front surface of the body 1. As shown in FIG.

3 is a fork which takes a cargo and stacks it, and is supported by the mast 2 via the lifting mechanism (not shown) provided with the lift cylinder 4.

The lift cylinder 4 is connected to the hydraulic pump 8 via the flow control valve 6 and the valve 5.

9 is a motor of the hydraulic pump 8, 10 is an oil tank, and the valve 5 and the hydraulic pump 8 are connected.

11 is a lift lever provided on a steering wheel (not shown).

When the lift operation lever 11 is operated, the detection signal of the lever operation angle detection sensor 22 is sent to the controller 20 as the lever operation angle of the operation lever 11, and the controller 20 sends this detection signal. When the valve is received, the valve 5 is opened and a driving command is given to the motor 9.

Thereby, the motor 9 operates at the drive speed according to the elevating operation lever angle, and adjusts the amount of pressurized liquid supplied from the hydraulic pump 8 to the lift cylinder 4. For this reason, the rod of the lift cylinder 4 extends, and the fork 3 rises.

The fork 3 is lowered by controlling the pressurized liquid returned from the flow rate control valve 6 to the oil tank 10 through the valve 5 by the weight of the fork.

However, in this conventional forklift unloading control device, when the lift operation lever 11 is operated to the maximum operating angle to open the valve 5 to lower the load, the flow control valve 6 functions until the flow control valve 6 functions. Since a large amount of the pressurized liquid is returned to the oil tank 10 through the flow control valve 6, the fork 3 descends, and when the flow control valve 6 functions and the flow rate is controlled, the flow returns to the oil tank 10. As the pressure of liquid is limited, the speed of descending the fork 3 suddenly slows down (it feels like thumping). As shown in FIG. 2 (b), the cargo 32 loaded on the fork has a gravity acceleration ( It vibrates by the temporal fluctuation of G).

This causes a collapse of the cargo 32 loaded on the fork 3.

The present invention aims to solve such a problem, and an object of the present invention is to provide a fork lift unloading control device capable of smoothly lowering the fork without causing collapse of cargo.

In order to achieve the above object, the forklift unloading control apparatus of the present invention includes a lift cylinder for elevating the fork, a hydraulic pump for distributing hydraulic fluid through a pipe to the lift cylinder, and a pipe for contacting the hydraulic pump and the lift cylinder. A proportional control valve installed, a load sensor for detecting the load of the cargo loaded on the fork, a lift operation lever, a lever operation angle detection sensor for outputting a detection signal corresponding to the operation direction and operating angle of the lift operation lever, And a controller for inputting the output of the sensor for detecting the lever operation angle to give the proportional control valve a drop valve opening command proportional to the magnitude of the detection signal during the fork operation, and controlling the hydraulic pump. The load detection value of the load sensor exceeds the set value, and the sensor for detecting the lever operating angle is detected. When the detection signal exceeds a predetermined value to, it characterized in that it limits the size of the descent valve open command.

In the above-described fork lift apparatus of the present invention, the controller opens the proportional control valve in response to the detection signal sent by the lever operation angle detection sensor, and loads the fork cargo based on the detection signal sent by the load sensor when the cargo is loaded. Limit the valve opening to the extent that collapse may occur.

EXAMPLE

EMBODIMENT OF THE INVENTION Hereinafter, the unloading control apparatus of the fork lift as one Example of this invention is demonstrated by drawing.

In FIG. 1, 21 is a load sensor (pressure sensor), detects the load of the cargo 32 loaded in the fork 3, and transmits the detection signal (load signal) to the controller 20. In FIG.

11 is a lift operation lever, which is disposed on a steering wheel (not shown). The lever operation angle of the lift operation lever 11 is detected by the lever operation angle detection sensor 22, and the detection signal (lever angle signal) is controlled by the controller. It is sent out to (20).

The controller 20 inputs the detection signals of the load sensor 21 and the lever operation angle detection sensor 22 to open and close the valve 7 and to drive and stop the motor 9 of the hydraulic pump 8. To control.

The valve 7 is connected to the controller 20, and has a mechanism of a proportional control valve that performs opening and closing control of the valve 7 in accordance with a valve opening and closing signal commanded by the controller 30.

30 and 31 are pallets and 32 are cargo.

Hereinafter, the functions of the loading control device will be described in order.

(1) When the driver turns the elevating operation lever 11 forward,

(a) The lever operating angle of the operating lever 11 is transmitted to the controller 20 when the detection signal of the sensor 22 for lever operation angle detection is sent to the controller 20, and the controller 20 receives this detection signal. Give the drive command.

As a result, the motor 9 operates at a drive speed corresponding to the lifting operation lever angle, thereby adjusting the amount of pressurized liquid supplied from the hydraulic pump 8 to the lift cylinder 4, and at the same time, the controller 20 opens the rising valve. Give a command to the valve (7).

As a result, the valve 7 opens the valve in a direction in contact with the lift cylinder 4 and the hydraulic pump 8, the pressurized liquid is supplied to the lift cylinder 4 through the pipe, and the rod of the lift cylinder 4 is closed. The fork 3 rises as it expands.

(b) Next, when the driver releases the elevating operation lever 11, the elevating operation lever 11 returns to the neutral position, and the detection signal transmitted by the lever operation angle detecting sensor 22 is zero. Therefore, the controller 20 gives a driving stop command to the motor 9 to stop the operation of the hydraulic pump 8 and gives a rising valve closing command to the valve 7.

For this reason, the valve 7 closes, the elongation of the rod of the lift cylinder 4 stops, and the fork 3 is maintained at the raised position.

(2) When the driver turns the elevating operation lever 11 upside down, the controller 20

(a) When the magnitude of the detection signal (load signal) outputted by the load sensor 21 indicates the set value or less (for example, when there is no cargo in the fork), the lever operating angle detection sensor 22 detects it. Based on the detection signal (lever angle signal), the valve 7 is provided with a lowering valve opening instruction corresponding to the lever operating angle.

Accordingly, the valve 7 opens the valve in a direction in contact with the lift cylinder 4 and the oil tank 10 at a valve opening degree corresponding to the lever operating angle, thereby loading the cargo 32 on the fork 3 and the fork 3. ), The pressure liquid returns from the lift cylinder 4 to the oil tank 10 through the valve 7, the rod of the lift cylinder 4 contracts, and the fork 3 descends.

(b) When the magnitude of the detection signal (load signal) output by the load sensor 21 exceeds the set value or more (when the fork loads a load), the lever operation angle detection sensor 22 detects If the detection signal (lever angle signal) exceeds a certain level, for example, the magnitude of the falling valve opening command output to the valve 7 is the magnitude that does not cause the cargo to collapse, even if the magnitude gives the maximum valve opening degree. Control with (valve open).

Therefore, the fork 3 lowers smoothly, and the temporal variation of the gravity acceleration G of the cargo 32 loaded on the fork 3 decreases rapidly as shown in FIG. The cargo 32 loaded in 3) is stable without impact and thus no collapse of the cargo occurs.

(c) Next, when the driver releases the elevating operation lever 11, the elevating operation lever 11 returns to the neutral position so that the detection signal sent by the lever operation angle detecting sensor 22 becomes zero, so that the controller The operation 20 gives a driving stop command to the motor 9, stops the operation of the hydraulic pump 8, and gives a lowering valve closing command to the valve 7.

As a result, the valve 7 closes, the contraction of the rod of the lift cylinder 4 stops, and the fork 3 is held at the lowered position.

Since the fork lift movement control of the present embodiment shows an embodiment in which the drive speed command corresponding to the lift operation lever angle is given to the motor 9, the fork lift movement control corresponds to the lift operation lever angle to the proportional control valve 7. The rise valve opening command may be given.

Thus, according to the unloading control apparatus of the fork lift of this embodiment, when the fork 3 is lowered, when there is cargo, the valve opening degree of the proportional control valve 7 is limited, and the fork 3 is lowered smoothly. Can be prevented and the collapse of the cargo can be prevented.

As described above in detail, according to the forklift unloading control apparatus of the present invention, the amount of liquid returned from the lift cylinder at the time of the fork lowering to the oil tank is directly controlled by the proportional control valve, and when there is cargo, the lever operation is performed. Even if the angle is large, the amount of liquid returned is controlled by a predetermined amount so that the fork can be smoothly lowered, thereby preventing the collapse of the cargo.

Claims (1)

A lift cylinder 4 for elevating the fork 3, a hydraulic pump 8 for distributing pressurized liquid through a pipe to the lift cylinder 4, and a pipe for communicating the hydraulic pump 8 and the lift cylinder 4 with each other. Operation direction of the proportional control valve 7 installed therein, the load sensor 21 for detecting the load of the cargo 32 loaded on the fork 3, the elevating operation lever 11, and the elevating operation lever 11 And a lever operating angle detection sensor 22 for outputting a detection signal corresponding to the operating angle and the output of the lever operating angle detection sensor 22, and fork-lowering operation is proportional to the magnitude of the detection signal. And a controller 20 for driving the hydraulic pump 8 at the same time as giving the lowering valve opening instruction to the proportional control valve 7, wherein the load detection value of the load sensor 21 is increased. The detection signal exceeding the set value and detected by the lever operation angle detection sensor is predetermined. Unloading control apparatus for a fork lift in the case of more than one, it characterized in that it limits the size of the descent valve open command a.