JPH072595B2 - Forklift load / push control device - Google Patents

Description

The present invention relates to industrial use of the present invention. By moving a face on a fork claw forward and backward, a load on a slip sheet is pulled up on the fork claw or pushed out from the claw for cargo handling work. The present invention relates to a load push / pull control device for a forklift.

2. Description of the Related Art Among the conventional load push-pull control devices, those that synchronize the forward / backward movement of the face with the forward / backward movement of the vehicle body are disclosed, for example, in Japanese Utility Model Publication No. 58-4599, Japanese Utility Model Publication No. 58-4600, and Japanese Utility Model Publication No. 58-4600. Many are known, such as the Sho 58-7797 publication.

Problems to be Solved by the Invention Even if the push-pull operation of the face can be synchronized with the longitudinal movement of the vehicle body by the automatic control, the automatic control should be temporarily stopped when performing lift correction, tilt correction, etc. Even if a slight correction operation is required, the correction operation tends to be omitted because the operation is troublesome for the operator, and the cargo handling efficiency deteriorates or the load collapses or This may cause damage to your luggage. Therefore, according to the present invention, even when the push-pull operation of the face is performed by the automatic control, if the control valve is manually operated, the correction operation is prioritized and the push-pull operation of the face is automatically stopped, and the fork and face are operated. It is intended to provide a load push-pull control device for a forklift capable of optimally compensating for the height and inclination of the cargo and improving the cargo handling work efficiency.

In the forklift equipped with the push-pull device that moves the face forwards and backwards on the forks of the forks by operating the control valve, the rotation of the wheels of the forkslift. A drive source as a drive source, an oil discharger including a pump that rotates normally and reversely in response to normal and reverse rotations of the wheel, and a switching valve that performs switching operation in conjunction with forward and reverse rotations of the pump, and Controlling the flow control valve between the oil discharger and the push-pull cylinder via the controller based on the detection actions of the face movement amount detector and the vehicle body movement amount detector to operate the push-pull cylinder. An automatic control device is installed side by side, and the oil discharger of the automatic control device is connected to and connected to the hydraulic oil carry-over circuit of the control valve.

Action If the control valve is manually operated during push-pull operation of the face by the automatic control device, the hydraulic oil carry-over circuit of the control valve is cut off and the hydraulic oil supply to the oil discharger is cut off. The correction operation by the control valve has priority.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

In the drawings, 1 is a vehicle body, 2 is a mast, 3 is a fork, and a face 5 which is moved forward and backward by a push-pull device 4 is arranged on a claw 3a of the fork 3. The push-pull device 4 includes a pantograph-type link mechanism 6 and a push-pull cylinder 7 that extends and retracts the pantograph-type link mechanism 6. Further, a gripper 9 for gripping and releasing an end portion of the slip sheet (not shown) by the operation of the grip cylinder 8 is attached to the lower side portion of the face 5. The push-pull cylinder 7 and the grip cylinder 8 are connected in a parallel circuit. Ten
Is a control valve for operating the push-pull cylinder 7, the lift cylinder 11, and the tilt cylinder 12, and a push-pull valve 13, a lift valve 14, and a tilt valve 15 are provided for each control valve. Reference numeral 16 is a power steering cylinder, 17 is a switching valve for the same, 18 is a flow dividing valve for dividing the hydraulic oil between the control valve 10 side and the switching valve 17 side, 19 is a pump driven by the engine 20, and 21 is a reservoir tank. . A sequence valve 23 is provided in the hydraulic oil circuit of the push-pull cylinder 7 so that the grip cylinder 8 can be operated to grip a slip sheet (not shown) prior to the backward movement of the face 5 by the push-pull cylinder 7. It is becoming like this. Reference numeral 24 is a flow rate adjusting valve provided in the hydraulic oil circuit 6 of the grip cylinder 8.

Reference numeral 25 denotes an automatic control device of the push-pull device 4 described above, which includes an oil ejector 26 and a flow control valve 29 provided between the oil ejector 26 and the push-pre-cylinder 7 and the grip cylinder 8.
It has and.

The oil dispenser 26 uses the wheels W of the forklift as a drive source,
A pump 27 that rotates forward and backward in response to the forward and reverse rotation of the wheel W.
And a switching valve 28 that performs switching operation in conjunction with forward and reverse rotations of the pump 27. This switching valve 28 moves the hydraulic fluid discharged from the pump 27 to the pull side of the push-pull cylinder 7 when the vehicle body 1 moves forward, and moves the hydraulic fluid discharged from the pump 27 to the push side of the push-pull cylinder 7 when the vehicle body 1 moves backward. It is designed to switch and supply to. The drive of the pump 27 is controlled by the electromagnetic clutch 32 which is operated via the controller 31 by the operation of the synchronous operation switch 30. The flow control valve 29 controls the vehicle body 1 according to the amount of rotation of the wheels W.
Based on the detection operations of the vehicle body movement amount detector 33 for detecting the movement amount of the face 5 and the face movement amount detector 34 for detecting the movement amount of the face 5 by the extension and contraction amount of the pantograph type link mechanism 6, the controller 31 It is controlled to open and close via
When the movement of the face 5 is too fast with respect to the movement of the vehicle body 1, the flow control valve 29 is opened to relieve a part of the hydraulic oil, and the movement of the face 5 is synchronized with the movement of the vehicle body 1. Then, the oil discharger 26, specifically, the switching valve 28 is connected to and connected to the hydraulic oil carry-over circuit 22 of the control valve 10 so that the hydraulic oil carried over from the control valve 10 is To be supplied to.

According to the apparatus of the above embodiment, the electromagnetic clutch 32 is connected through the controller 31 by turning on the synchronous operation switch 30, and the power transmission system between the pump 27 of the oil discharger 26 and the wheel W is continued. . When the vehicle body 1 moves forward slowly to load the luggage, the pump 27 is rotated along with the forward movement of the wheels W.
, But at the same time, the switching valve 28 switches from the neutral position to the pull side to supply the hydraulic oil to the pull side of the push-pull cylinder 7, but the sequence valve 23 causes the push-pull cylinder 7 to pull earlier than the pull operation. Grip cylinder 8
The hydraulic oil is supplied to the gripper, and the gripper 9 grips the end of the slip seat (not shown), and at the same time, push-pull cylinder 7
Pulls to move face 5 backwards. Therefore,
Due to the forward movement of the vehicle body 1 and the pulling operation of the load by the push-pull device 4, the load 3 stays in the fixed position and the claws of the forks 3 are held.
Capture on 3a. Here, since the push-pull cylinder 7 is a single rod, the volume of the pull-side oil chamber is smaller than the volume of the push-side oil chamber, and depending on the amount of hydraulic oil supplied from the oil discharger 26, the push-pull cylinder 7 is less than the push-pull operation. Although the pulling operation becomes faster, the backward movement operation of the face 5 tends to be faster than the forward movement of the vehicle body 1. However, the vehicle body movement amount detector 33 and the face movement amount detector 34
This deviation is quickly detected by
The flow rate control valve 29 is opened via 31 and a part of the hydraulic oil is relieved, so that the forward movement of the vehicle body 1 and the backward movement operation of the face 5, that is, the pulling operation of the load are kept in synchronism. At the time of unloading, if the vehicle body 1 is retracted, the pump 27 of the oil discharger 26 is rotated in reverse,
By the push-side switching of the switching valve 28, the hydraulic oil is supplied to the grip cylinder 8 and the push-side of the push-pull cylinder 7, and simultaneously with the release of the slip seat by the gripper 9, the face 5 is moved forward to move the load to a fixed position. As it is, lower it from the nail 3a of the fork 3. During such cargo handling work by the automatic control device 25, the control valve 10
Is manually operated, the hydraulic oil carry-over circuit 22 of the control valve 10 is cut off, and the hydraulic oil supply to the oil discharger 26 is cut off. Manual operation by 10 has priority. Therefore, the tilt control valve 15 is operated to operate the tilt cylinder 12 to correct the angle of the mast 2, and the lift control valve 14 is operated to operate the lift cylinder 11 to move the fork 3 up and down. It can be corrected. Further, by operating the push-pull control valve 13, the push-pull operation and pull operation of the push-pull device 4 can be corrected. When these correction operations are completed, the hydraulic oil carryover circuit 22 is opened. , Can return to automatic control immediately.

As described above, according to the present invention, since the oil discharger of the automatic control device is connected to and connected to the hydraulic oil carryover circuit of the control valve, the synchronous cargo handling work by the automatic control of the push-pull device is performed. In addition, if the control valve is manually operated, the operation control by this control valve has priority, and tilt correction, lift correction, or push-pull correction can be arbitrarily and easily performed to further improve the cargo handling work efficiency. You can Further, the automatic control device uses an oil dispenser that operates using the wheels of the forklift as a drive source to synchronize the forward and reverse rotations of the wheels with the push-pull operation of the push-pull cylinder, that is, the vehicle body. The forward and backward movements can be easily synchronized with the push-pull operation of the push-pull device, which has a practically great effect that safer cargo handling work can be performed.

[Brief description of drawings]

The drawing is a hydraulic circuit diagram showing an embodiment of the device of the present invention. 1 ... Car body, 3 ... Fork, 3a ... Claw, 4 ... Push-pull device, 5 ... Face, 7 ... Push-pull cylinder, 10 ... Control valve, 22 ... Hydraulic oil carryover circuit, 25 …… Automatic control device, 26 …… Oil dispenser, 27 …… Pump, 28 …… Switching valve, 29 …… Flow control valve,
31 …… Controller, 33 …… Vehicle movement amount detector, 34 ……
Face movement amount detector, W ... Wheel.

Claims (1)

[Claims] 1. A forklift equipped with a push-pull device for operating a push-pull cylinder by operating a control valve to move a face forward and backward on a fork claw. As an oil discharger including a pump that rotates forward and backward in response to forward and backward rotation of the wheel, and a switching valve that performs switching operation in conjunction with forward and reverse rotation of the pump, and a face Based on the detection functions of the movement amount detector and the vehicle body movement amount detector, the oil ejector and push
An automatic control device for controlling the flow control valve between the pull cylinder and the push-pull cylinder is installed, and the oil discharger of the automatic control device is connected to a hydraulic oil carryover circuit of the control valve. Forklift load push-pull control device characterized by being connected.