JPS60171999A - Controller for speed of reaching of reaching forklift truck - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a reach speed control device a for a reach forklift truck that is capable of controlling the reach speed, etc. according to the lift height of the mast.

BACKGROUND OF THE INVENTION In recent years, in order to improve loading efficiency in warehouses, reach forklift trucks that are small and capable of high-lift cargo handling operations have been in demand.

However, small reach forklift trucks have a problem in that their stability deteriorates as the lift height increases.

Purpose of the Invention Reach speed control for reach forklift trucks that enables even small vehicles to safely perform high-lift cargo handling operations by controlling the reach speed and acceleration/deceleration characteristics during starting and stopping in accordance with mast lift height. The aim is to provide equipment.

Components of the invention The lift height is detected by an FC lift height detector installed in the mast, and the obtained signal is input to the reach speed control circuit to calculate acceleration/deceleration speed and reach speed according to the lift height. A reach speed control device for a reach forklift truck that enables high-lift cargo handling operations to be performed safely by controlling the discharge amount of a hydraulic pump that supplies hydraulic pressure to a reach cylinder using a reach speed signal.

In the drawings of the embodiment, reference numeral 1 denotes the body of a reach forklift truck that can move freely, and is equipped with a mast 2 that is movable in the front and rear directions, and a fork 3 is attached to this mast 2 so that it can freely move up and down. A reach cylinder 4 is provided between the lower part of the mast 2 and the rear part of the vehicle body 1. Hydraulic pressure is supplied to this reach cylinder 4 from a hydraulic pump 5 via a reach operation valve 6. The mast 2 can be moved back and forth, that is, reach operation can be performed by this, and a reach detector 7 is attached to the reach operation valve 6 to detect the operation of the reach operation valve 6. . In addition, the mast 2 includes an outer mast 2cz that stands upright on the side of the vehicle body 1, an inner mast 2h that can move up and down with respect to the outer mast 2α, and an outer mast 2.
A lifting height detector 8 consisting of a rotary encoder or the like is provided at the top of α, and this lifting height detector 8 can detect the lifting height of the fork 3, and the lifting height detector 8 and The signals detected by the reach detector 7 are respectively input to the reach speed control circuit 9, and based on these signals, the reach speed control circuit 9 controls the rotation of the electric motor 1° that drives the hydraulic pump 5. It is controlled via the circuit 11 as follows.

To explain the action, it is now placed on the fork 3 and the 7'C
ff When the fork 3 is raised together with the inner mast 2h to unload the cargo 12, the lift height of the fork 3 is detected by the lift height detector g.
It is detected and inputted to the reach speed control circuit 9. The reach speed control circuit 9 stores in advance a reach speed map for high lift as shown in FIG. 2 and a reach speed map for low lift as shown in FIG.
The reach speed for the reach stroke S is calculated from the high lift map when the lift becomes high, and from the low lift map when the lift is low. That is, the reach speed is determined for the reach stroke S so that acceleration and deceleration are performed along a gentle curve when the lift is high, and acceleration and deceleration are performed along a steep curve when the lift is low. The reach speed determined by the reach speed control circuit 9 is output to the rotation control circuit 11, and the electric motor 1 drives the hydraulic pump 5 in the rotation control circuit 11.
The rotation of o is controlled. As a result, when the reach operation valve 6 is operated to reach the fork 3, the mast 2 is reached with acceleration/deceleration characteristics in accordance with the high-lift map when the lift is high, so that cargo handling operations at high lift can be carried out safely. Become.

Furthermore, when the lifting head is low, reaching is performed with the same acceleration/deceleration characteristics as in the past, so that the failure of i, which reduces work efficiency, does not occur at all.

In the above embodiment, a reach speed map for high lifts and a reach speed map for low lifts were prepared in advance, and these were selected according to the lift height, but as shown in Fig. 4. The lift height may be continuously detected and the acceleration and deceleration characteristics may be changed steplessly according to the obtained lift height.

Effects of the Invention As described in detail above, this invention detects the lift height of the fork and controls the acceleration/deceleration characteristics and the reach speed during reach according to the lift height. Stable dynamic characteristics can be obtained even when vehicles perform high-lift cargo handling operations. This allows high-lift work to be carried out safely, and by making the vehicle more compact, it is possible to significantly improve maneuverability and loading efficiency within the warehouse.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, with Fig. 1 being a circuit diagram, Fig. 2 being a diagram showing the relationship between the reach stroke and reach speed at high lift, and Fig. 3 showing the reach stroke and reach at low lift. A diagram showing the relationship between speeds, FIG. 4 is a diagram when the acceleration characteristics are continuously changed according to the lift height. 1 is the vehicle body, 2 is the mast, 3 is the fork, 8 is the lift height detector, and 9 is the reach speed control circuit. Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A self-propelled unit 1 is provided with a mast 2 that can move forward and backward by a reach cylinder 4, and a 7 oak 3 is attached to this mast 2 so that it can move up and down, and a part of the mast 2 is equipped with a lift height detector. 8 to detect the lift height of the fork 3,
The obtained lifting control (IT number) is input to the reaching speed control circuit 9, and the reaching speed and acceleration/deceleration speed are calculated according to the lifting height, and the reaching speed of the lifting mast 2 is controlled using the obtained control signal. A reach speed control device for a reach forklift truck, characterized by: