JPH05318B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a side shift device as an attachment installed on a forklift.
The present invention relates to a device that automatically returns a fork together with a finger bar so that the side shift is in a neutral position, that is, the center of the fork is located on the vehicle center line.

(Prior Art) Generally, a side shift device for a forklift has a configuration in which a shift cylinder is actuated to side shift the fork to the left or right by tilting a side shift lever and switching a hydraulic control valve. It's summery.

(Problem to be Solved by the Invention) Therefore, in the conventional side shift device, after loading the fork with the fork side shifted to the left or right, the fork is returned to the center line of the vehicle together with the finger bar in the neutral position. Since the return operation is left to the driver, the vehicle may be driven in a posture in which the return operation is not performed due to the driver's carelessness or the like. However, traveling with a fork, that is, with the load biased to either the left or right side, is dangerous because the lateral stability of the vehicle is poor. Furthermore, even if the fork is returned to its neutral position, this is based solely on the driver's intuition, and it is not always possible to align the center of the fork with the vehicle center line.

(Means for Solving the Problems) In order to solve the above-mentioned conventional problems, the present invention provides a lift bracket that is moved up and down along the mast, and a lateral movement of the lift bracket in the left and right direction via a guide member. In a forklift equipped with a finger bar for supporting a fork that can be attached to the forklift, and a shift cylinder that moves the finger bar laterally, a means for detecting operation of a side shift cargo handling lever, and detecting a lift height of the fork. means for detecting the backward tilt angle of the mast; means for detecting the neutral position of the finger bar; a side shift cargo handling lever operation signal; a fork lift height signal; a mast backward tilt angle signal; Upon receiving the position signal, the lift height of the fork and the backward tilt angle of the mast are each within the set range, and
A side shift control device is constituted by a control circuit that outputs an actuation signal to the electric control valve for controlling the shift cylinder when the position of the finger bar is outside the set range.

(Function) When the side shift cargo handling lever is operated to side shift the fork from the neutral position to the right or left, the operation signal is input to the control circuit. In such a situation, if the driver uses the fork to pick up cargo in a normal cargo handling operation and then assumes a running position, that is, moves the fork to a height position suitable for running, and then moves the mast to the running position. When tilting back to a preferred position, a detection signal of this is respectively input to the control circuit. At this time, if the signal input to the control circuit from the finger bar position detection means indicates a shift of the fork to the right or left, the control circuit sends an activation signal to the electric control valve for controlling the shift cylinder. Output. Therefore, by actuation of the electric control valve, the shift cylinder returns the fork together with the finger bar to the neutral position, ie, the center position. After the return, the electric control valve is returned to the neutral position.

(Example) Hereinafter, an example of the present invention will be specifically described based on the drawings.

In FIG. 1, 1 is a mast that is tilted back and forth by a tail cylinder 2, and 3 is a lift bracket that is raised and lowered along the mast 1. On the front side of the lift bracket 3 is a finger bar that supports a fork 4. 5 is attached so as to be laterally movable in the left-right direction via a guide bar 6, and is adapted to be moved by a shift cylinder 7. 8 is an oil pump, 9 is an oil tank, and 10 is an electric control valve (electric oil control valve) that controls supply and discharge of hydraulic oil to and from the shift cylinder 7. Reference numeral 11 indicates a side shift loading lever that automatically returns to the neutral position, and 12 indicates an angle sensor (for example, a rotary potentiometer) that detects the tilt angle of the load handling lever 11. The output voltage is converted into a digital value via an A/D converter (not shown) and input to the control circuit 13.

14 is a neutral position sensor (for example, a linear potentiometer) attached to the shift cylinder 7 to detect the neutral position of the side shift, that is, the neutral position of the finger bar 5; left and right forks 4
A voltage corresponding to the amount of shift in the left and right direction is output based on the position where the center line coincides with the vehicle center line, and the output voltage is converted into a digital value via an A/D converter (not shown). and is input to the control circuit 13. Reference numeral 15 denotes a backward tilt angle sensor (for example, a rotary potentiometer) attached to the tilt cylinder 2 to detect the backward tilt angle of the mast 1, and outputs a voltage corresponding to the tilt angle. The output voltage is converted into a digital value via an A/D converter (not shown) and input to the control circuit 13. 16 is a proximity switch attached to the lift bracket 3 as a lift height detection sensor for detecting the lift height of the fork 4;
A vertically long dog 17 installed to face the
is turned on and off by
The signal is input to the control circuit 13.

Therefore, the control circuit 13 controls each of the sensors 12,
Based on the detection signals from 14, 15 and the proximity switch 16, an actuation signal is output to the electric control valve 10. Specifically, this activation signal is set to be output when the vehicle assumes a running attitude while the finger bar 5 is shifted to either the left or right, and in this embodiment, As a condition for the running posture, the backward inclination angle of mast 1 is
For example, the angle is 8 to 13 degrees, and the lift height of the fork 4 is set to, for example, 150 to 500 mm. Note that the condition for the neutral position of the side shift is set to ±50 mm with respect to the reference.

The lift cylinder (not shown) and tail cylinder 2 can be controlled by switching manual oil control valves by tilting the lift and tail cargo handling levers, or as in the case of the above shift. Any type that uses an angle sensor to switch an electric control valve may be used.

Next, automatic return control of the side shift to the neutral position will be explained based on the flowchart shown in FIG. When you turn on the vehicle's key switch,
After the initial settings are made in step 1, the process proceeds to step 2, where the tilt angle of the cargo handling lever 11 for side shift is read, and then in step 3, it is determined whether or not the cargo handling lever 11 has been tilted, and the tilting operation is confirmed. If it has not been performed, the answer is NO, so return to step 2 and repeat steps 2-3. If the judgment result is YES, proceed to step 4 to read the lift height data, and in step 5 judge whether or not the fork 4 is within the range of the set value (150 to 500 mm). If so, return to step 4 and repeat steps 4-5. If YES, proceed to step 6, read the mast 1 aft angle data, and in step 7, the aft angle becomes the set value (8 to 8).
13 degrees), and if NO, return to step 4 and repeat steps 4-5-6-7.
If YES, proceed to step 8, read side shift neutral data, and then proceed to step 9.

In step 9, it is determined whether the position of the finger bar 5 is within the range of the set value (the center of the fork is 50 mm from the center of the vehicle), and if YES, the process returns to step 4 and steps 4-5-6-7-8 Repeat -9. However, if the fork 4 is side-shifted to the left or right beyond the set value, the answer is NO, and the process proceeds to step 10, where it is determined whether the shift position of the fork 4 is to the left or the right. If it is on the left side, proceed to step 11 and output a switching signal to the electric control valve 10 for controlling the shift cylinder.
By the switching operation of the electric control valve 10, the fork 4
will be moved from left to right along with the finger bar 5, and if it is determined that it is on the right side, the step
Proceeding to step 12, a switching signal is output to the electric control valve 10, so that the electric control valve 10 is switched in the opposite direction to the above, and the fork 4 is moved from right to left together with the finger bar 5. After passing step 11 or 12, return to step 8 and proceed to 8-9-10.
-Repeat 11 or 12. When the finger bar 5 returns to the neutral position (within the set value),
If the decision in step 9 is YES, proceed to step 4.
, the actuation signal to the electric control valve 10 is stopped, and the electric control valve 10 is automatically returned to the neutral state.

The above-mentioned automatic return of the fork 4 to the neutral position is not performed when the vehicle is in the loading position, that is, when the mast 1 is tilted forward or straight, or when the fork 4 is rising to pick up a load from a high place. This is executed only when the above-mentioned running posture conditions are satisfied.

In addition, according to this embodiment, the fork 4 is automatically returned to the neutral position when the running posture conditions are satisfied, and therefore, depending on the work content, this may be rather inconvenient. Therefore, the above-mentioned inconvenience can be solved by, for example, installing a cancel button and configuring the control circuit 13 so that the operation by the driver takes priority.

In addition, since there are cases where it is desired to automatically return the fork 4 to the neutral position even in a state other than the running position, a neutral return button is installed, and when the neutral return button is operated, the fork 4 is automatically returned to the neutral position via the control circuit 13. It is possible to configure

Note that the sensors described in the embodiments are merely examples, and may be replaced with other sensors.

(Effects of the Invention) As detailed above, according to the present invention, in the side shift device of a forklift, it is possible to automatically perform the operation of returning the fork to the neutral position, which was conventionally left to the operator. In addition to improving safety, it also ensures a stable posture and improves safety during driving.

Furthermore, in the present invention, the side shift is automatically returned when the lift height of the fork and the backward tilt angle of the mast are each within the setting range suitable for traveling, so that the traveling posture is adjusted. There is no possibility that the automatic return operation of the side shift will be executed even though the side shift is not turned on, causing problems during cargo handling operations.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a control system diagram of a side shift control device (however, for convenience of explanation, the side shift device is shown with imaginary lines);
FIG. 2 is a flowchart of the control circuit. 1...Mast, 4...Fork, 5...Finger bar, 6...Guide bar, 7...Shift cylinder, 10
...Electric control valve, 11...Cargo handling lever, 12...Angle sensor, 13...Control circuit, 14...Neutral position sensor,
15... Backward angle sensor, 16... Proximity switch.

Claims (1)

[Claims] 1. A lift bracket that is moved up and down along the mast, a finger bar for supporting the fork that is attached to the lift bracket via a guide member so as to be able to move laterally in the left and right direction, and a shift cylinder that moves the finger bar laterally. In the forklift equipped with the forklift, means for detecting the operation of the side shift cargo handling lever, means for detecting the lifting height of the fork,
Means for detecting the backward tilt angle of the mast, means for detecting the neutral position of the finger bar, an operation signal of a side shift cargo handling lever, a lift height signal of a fork, a backward tilt angle signal of the mast, and a finger bar position signal. In response to this, when the lift height of the fork and the backward tilt angle of the mast are each within the setting range suitable for running, and the finger bar is outside the setting range of the neutral position, the electric control valve for controlling the shift cylinder is activated. A forklift side shift control device comprising a control circuit that outputs an operating signal to a forklift.