JP2624030B2 - Control device for forklift - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forklift control device.

[0002]

2. Description of the Related Art A conventional technique will be described below with reference to the drawings.

In FIG. 3, reference numeral 1 denotes a vehicle body of a forklift vehicle driven by a battery, 1A denotes wheels, and 2 denotes a vehicle body.
Is a mast (an outer mast, an inner mast (not shown)) supported via a tilt mechanism (not shown) including a tilt cylinder 4 on the front surface of the mast. Numeral 3 denotes a fork for loading and unloading, and is supported by a mast 2 (an inner mast not shown) via a lifting mechanism (not shown) having a lift cylinder 5. The tilt cylinder 4 is connected to a hydraulic pump 8 via a valve 6, and the lift cylinder 5 is connected to a hydraulic pump 8 via a valve 7. 9 is a motor of the hydraulic pump 8. Reference numeral 10 denotes a hydraulic tank, which is connected to the valve 6, the valve 7, and the hydraulic pump 8. Numeral 11 denotes a tilt lever, and numeral 12 denotes a lift lever, both of which are arranged in a driver's cab (not shown). When operated toward the user, an operation signal is sent to the control circuit 20. A drive command is given to the motor 9 to operate the hydraulic pump 8. The tilt lever 11 controls opening and closing of the valve 6, whereby the rod of the tilt cylinder 4 moves forward and backward, and the fork 3 is switched between the horizontal position and the inclined position. The lift lever 12 opens and closes the valve 7. When the hydraulic fluid is supplied from the hydraulic pump 8 to the rod of the lift cylinder 5, the fork 3 moves up and down by the weight of the fork 3 side.

[0004]

In this conventional control device, the tilt angle and the elevation of the fork of the forklift are controlled by operating the tilt lever and the lift lever. However, the two types of levers must be individually and simultaneously operated during the unloading and loading operations, and therefore, a skilled operating technique is required.

The present invention has been made to solve this problem, and includes a loading operation lever for controlling the tilt angle of the fork and a lifting / lowering control during the loading operation, and a fork during the loading operation. A fork control is provided by providing a loading operation lever for controlling the tilt angle of the fork and raising and lowering the control, and operating only one type of operation lever in accordance with the work content of the forklift. To provide a control device capable of performing

[0006]

According to the present invention, a tilt cylinder for tilting a fork, a lift cylinder for raising and lowering a fork, a tilt cylinder for raising and lowering the fork, and a pressure pipe connected to the lift cylinder are provided. A hydraulic pump for supplying and discharging liquid, a first valve provided in a pipe connecting the hydraulic pump to the tilt cylinder, and a second valve provided in a pipe connecting the hydraulic pump to the lift cylinder. A valve, a tilt angle detection sensor for detecting the tilting of the fork, a presence sensor for detecting the presence of the fork, and a loading instruction corresponding to the operating angle and operating direction of the loading operation lever. , A loading sensor that outputs a loading instruction corresponding to the operation angle and operation direction of the loading operation lever, the output of each of the above sensors, the valve and the hydraulic pump A control circuit for controlling, the control circuit, when subjected to the load pickup instruction, executes the load pickup program, when subjected to the load deposition instruction, and executes a load deposition program.

[0007] The loading program gives an ascending or descending valve opening command to the second valve based on the output of the loading sensor, and determines whether the fork is tilted based on the output of the tilt angle detecting sensor. Detect, fork tilts,
If the presence sensor does not detect the presence, the first
When the fork sensor detects the presence and the tilt angle detection sensor detects the horizontal attitude of the fork, the first valve is tilted and opened. It is characterized by giving a valve command.

The loading program gives an ascending or descending valve opening command to the second valve based on the output of the loading sensor, a tilt angle detecting sensor detects tilting of the fork, and a loading sensor. When a is detected, a horizontal return valve opening command is given to the first valve.

[0009]

The control device according to the present invention has a control circuit for controlling the valves and the hydraulic pump by inputting the output of each sensor, and executes a load program when receiving a load command. When a command is received, the loading program is executed, thereby eliminating the need for skilled operation skills in a conventional fork control device, and fork tilting during forklift loading and loading operations. Angle and elevation control can be performed.

[0010]

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 21 denotes a tilt angle detecting sensor which detects the tilt angle of the fork 3 and sends a detection signal (tilt angle signal) to the control circuit 20. 22
Is a load sensor (pressure sensor) which detects the presence or absence of a load and, when the fork 3 is present (loading), sends a detection signal (load signal) to the control circuit 20. To send to.
23 is a loading operation lever, and 24 is a loading operation lever.
Both are arranged in a driver's cab (not shown), and the lever operation angle of the operation lever 23 is detected by the load sensor 25A, and the lever operation angle of the operation lever 24 is detected by the load sensor 25B. Then, each detection signal (lever angle signal) is sent to the control circuit 20. The control circuit 20 includes a tilt angle detection sensor 21, a presence sensor 22, and a pickup sensor 2.
5A, the detection signal of the load sensor 25B is input, and the opening and closing of the valves 6, 7 and the driving and stopping (ON / OFF driving) of the motor 9 of the hydraulic pump 8 are controlled in accordance with the sequence described below. I do. The valve 6 is connected to the control circuit 20, and a solenoid valve for controlling the opening and closing of the valve 6 in accordance with a valve opening and closing signal instructed by the control circuit 20. The valve 7 is connected to the control circuit 20 and instructed by the control circuit 20. It has a mechanism of a proportional control valve for controlling the opening and closing of the valve 7 according to the valve opening and closing signal.

Hereinafter, the function of the forklift control device will be described step by step.

1) The driver operates the unloading operation lever 23 when unloading the load 32. When the loading operation lever 23 is moved down, the control circuit 20 executes a loading program shown in FIG.

A) a drive command is given to the motor 9 to operate the hydraulic pump 8; and b) whether the fork 3 is tilted based on the output of the tilt angle signal sent from the tilt angle detecting sensor 21. C) based on the output of the presence signal sent by the presence sensor 22;
It is checked whether the fork 3 is picking up the baggage 32 (load state or no load state).

D) If the fork 3 is tilted backward (mast side) by the angle θ, the fork 3 will not be able to send a signal indicating that the fork 3 Is returned to the valve 6 on the condition that it has not been picked up, and a valve opening command is given. As a result, the valve 6 is opened, the pressure fluid is supplied to one room of the tilt cylinder 4 through the pipe, the lot of the tilt cylinder 4 is extended, and the fork 3 is displaced to a horizontal posture.

When the fork 3 is in the horizontal posture, a horizontal return valve closing command is given to the valve 6, whereby the valve 6 closes, the extension of the rod of the tilt cylinder 4 stops, and the fork 3 It is held in its horizontal position.

E) Simultaneously with the above operation, the control circuit 20 gives the valve 7 an ascending valve opening command corresponding to the lever operation angle based on the lever angle signal sent by the unloading sensor 25A. As a result, the valve 7 opens in a direction in which the hydraulic pump 8 and the lift cylinder 5 communicate with each other at a valve opening degree corresponding to the lever operation angle, and pressurized liquid is supplied to the lift cylinder 5 through the pipe. Is extended, and the fork 3 rises.

2) When the driver releases the operating lever 23 when the fork 3 has risen to the same height as the pallet 30,
The operation lever 23 returns to the neutral position and the control circuit 20
A) Since the lever angle signal sent out by the unloading sensor 25A becomes 0, an ascending valve closing command is given to the valve 7. This allows
The valve 7 closes, the ascent of the fork 3 stops, and the fork 3
Is held in its raised position, and is in a position where it can be unloaded.

3) Next, the driver moves the car forward in this fork position, inserts the fork 3 into the pallet 30, and then lowers the loading operation lever 23 to the front. In the same manner as described above, the valve 7 is opened, and the fork 3 takes up the pallet 30 so that the pallet 30 can be transported.

B) At this time, since the presence sensor 22 detects the package 32, the control circuit 20 receiving the output of the presence sensor 22 gives the valve 6 a tilt valve opening command. Thereby, the pressurized liquid is supplied to the other chamber of the tilt cylinder 4,
The rod of the tilt cylinder 4 contracts, and the fork 3 is tilted backward by a predetermined angle θ.

4) When the driver releases the unloading operation lever 23, the unloading operation lever 23 returns to the neutral position, and the control circuit 20 a) closes the valve 7 in the same manner as described above. When the fork 3 stops rising, the fork 3 is held in its raised position.

5) When the loading operation lever 23 is tilted in the reverse direction, the control circuit 20 outputs the loading signal from the loading sensor 22 if the fork 3 is tilted backward by the angle θ. Is given (provided that the fork 3 has not picked up the luggage 32), a valve opening command is given to the valve 6, the valve 6 is opened, and the fork 3 is brought to the horizontal position. As the posture changes, the valve 6 closes in the same manner as described above,
3 is held in its horizontal position. Also, a lowering valve opening command is given to the valve 7, whereby the valve 7 opens in a direction to connect the lift cylinder 5 and the oil tank 10, and the pressure liquid flows through the pipe by the weight of the fork 3 and the load 32. Oil tank 10
And fork 3 descends. Operation lever for loading
When the release lever 23 is released, the operation lever 23 returns to the neutral position, the valve 7 closes, the lowering of the fork 3 stops, and the fork 3 is held at the lower position.

6) After driving the car to the loading place,
When the loading operation lever 24 is tilted toward the front for loading, the control circuit 20 executes the loading program shown in FIG.

A) The fork 3 is checked for tilt based on the tilt angle signal sent from the tilt angle detecting sensor 21. If the fork 3 is tilted, the load sensor 22 outputs a presence signal. (Condition that the fork 3 is picking up the baggage 32) and returns to the valve 6 to give a valve opening command. As a result, the valve 6 is opened, the pressure fluid is supplied to one room of the tilt cylinder 4 through the pipe, the lot of the tilt cylinder 4 is extended, and the fork 3 is displaced to a horizontal posture.

B) The control circuit 20 also gives the valve 7 a downward valve opening command corresponding to the lever operation angle based on the lever angle signal sent from the load sensor 25B. As a result, the valve 7 opens in a direction in which the lift cylinder 4 and the oil tank 10 communicate with each other at an opening degree corresponding to the lever operation angle, and the hydraulic fluid passes through the pipe due to the dead weight of the fork 3 and the load 32. Tank 1
Returned to 0. As a result, the fork 3 descends. When the operation lever 24 for loading is released at the position where the pallet 30 arrives at the loading area, the operation lever 24 returns to the neutral position, the valve 7 closes, and the lowering of the fork 3 stops. Then, fork 3 is held at its lowered position.

7) When the loading operation lever 24 is tilted upside down, the control circuit 20 determines that the fork 3 is tilted backward (mast side) by the angle θ and the load sensor 22 On the condition that the fork 3 is outputting a stock signal (on the condition that the fork 3 is picking up the baggage 32), a return valve opening command is given to the valve 6 and a rising valve opening command is sent to the valve 7. , The fork 3 is displaced to the horizontal position and raised.

As described above, in this embodiment, when the operation lever 24 is operated, the control of the fork 3 to the loading position and the control of the fork 3 to the transfer position after the loading are automatically performed. I,
Further, when the loading operation lever 25 is operated, the fork 3 is automatically controlled to the loading position, so that two levers are used for loading or loading as in the conventional case. Need not be operated, and only one lever operation is required, so that the unloading or loading operation can be performed safely even by a non-expert.

[0028]

As described above, according to the present invention, only one type of operation lever, ie, the operation lever for unloading and the operation lever for unloading, is operated in accordance with the contents of the unloading and unloading work, and thus the load can be unloaded. There is an effect that the tilt angle of the fork of the forklift vehicle and the ascent / descent control can be performed at the time of loading and unloading.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a forklift control device as one embodiment of the present invention.

FIG. 2 is a flowchart showing command contents and a command procedure of the unloading and loading program of the present invention.

FIG. 3 is a schematic configuration diagram showing a conventional forklift control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Forklift car body 1A Wheel 2 Mast 3 Fork 4 Tilt cylinder 5 Lift cylinder 6 Valve 7 Valve 8 Hydraulic pump 9 Motor 10 Oil tank 11 Tilt lever 12 Left lever 20 Control circuit 21 Tilt angle detection sensor 22 Loading sensor (pressure sensor) 23 Loading operation lever 24 Loading operation lever 25A Loading sensor 25B Loading sensor 30, 31 Pallet 32 Luggage

Claims (3)

(57) [Claims] 1. A tilt cylinder for tilting a fork, a lift cylinder for raising and lowering a fork, the tilt cylinder, a hydraulic pump for supplying and discharging hydraulic fluid through a pipe to the lift cylinder, the hydraulic pump and the tilt cylinder A second valve provided in a pipe connecting the hydraulic pump and the lift cylinder, and a tilt angle detecting whether the fork is tilted or not. A detection sensor, a presence sensor for detecting the presence or absence of a fork, a loading sensor for outputting a loading instruction corresponding to the operation angle and operation direction of the loading operation lever, and a loading operation lever. A load sensor that outputs a load instruction corresponding to the operation angle and operation direction of the sensor, and a control circuit that inputs the output of each of the sensors and controls the valve and the hydraulic pump. When receiving the load pickup instruction, when running the load pickup program, it has received the load deposition instruction,
A forklift control device for executing a loading program. 2. A loading program gives an ascending or descending valve opening command to the second valve based on the output of the loading sensor, and determines whether or not the fork is tilted based on the output of the tilt angle detecting sensor. When the fork is tilted and the load sensor does not detect the load, the horizontal return opening instruction is given to the first valve, and the load sensor detects the load,
2. The forklift control device according to claim 1, wherein when the tilt angle detecting sensor detects the horizontal posture of the fork, a tilt valve opening command is given to the first valve. 3. The loading program gives an ascending or descending valve opening command to the second valve based on the output of the loading sensor, and the tilt angle detecting sensor detects tilting of the fork, and 2. The forklift control device according to claim 1, wherein a horizontal return valve opening instruction is given to the first valve when the load sensor detects the presence of the load.