JPH0664900A - Fork shifter - Google Patents

Abstract

PURPOSE:To provide a fork shifter which causes simple regulation of a distance between forks without arranging a large scale of oil pressure pipings on the machine bed side, in a fork-lift constituted such that a distance between a pair of forks is regulatable through rotation of a screw shaft inserted in both two forks. CONSTITUTION:A fork shifter comprises a switching valve 18 disposed on a machine bed 19 and connected to an oil pressure line for cargo handling and a shifter unit 25 removably coupled to the switching valve 18. Equipment on the machine bed side is minimized and a distance between forks is regulatable by means of a shifter unit 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fork shifter adapted to change and adjust the distance between a pair of forks by utilizing the hydraulic pressure of a cargo handling hydraulic device.

[0002]

2. Description of the Related Art In a general forklift truck, as shown in FIG. 4, both forks 2 are suspended on a finger bar 1 and a screw shaft 3 is inserted in both forks 2 by using a handle tool or the like (not shown). By rotating the screw shaft 3, the fork interval is changed and adjusted.

Further, as an arrangement for utilizing mechanical power instead of such manual operation, the idea of providing a dedicated power source such as an electric motor, and the engine or battery of a forklift truck instead of such a single power source. There is a concept of utilizing the power of an operating hydraulic system or a rotating body. In the former case, for example, there is one in which an electric motor controlled by a machine side controller is attached to the screw shaft.
In this case, the electric motor is attached to one of the left and right ends of the screw shaft or the center thereof. In the latter, there is one in which a pulley attached to a screw shaft is positively tilted backward to bring the pulley into contact with a tire, and the screw shaft is rotated in response to forward and backward movement of the vehicle.

[0004]

However, in the case where an electric motor is attached to the screw shaft, the electric motor does not participate in the cargo handling work and impairs the front field of view of the worker during the cargo handling work or traveling. It is extremely uneconomical to provide an electric motor for adjusting the distance between each machine base. Further, the electric motor is unaesthetic in appearance.

Further, in the case where the pulley is brought into contact with the tire, the amount of forward and backward movement of the vehicle corresponds to the amount of movement of the fork, and its adjustment is troublesome and requires skill. Further, the fork tilt angle until the pulley hits the tire must be taken into consideration, which increases design restrictions. It is also conceivable to take the power from the hydraulic circuit of the forklift and drive the hydraulic motor attached to the screw shaft, but in this case, the piping to the hydraulic motor bypasses the upper part of the mast via the hose reel. It will be a structure.

An object of the present invention is to provide a fork shifter in which each machine base is provided with a minimum required number of elements and other necessary elements are united so that they can be shared.

[0007]

A fork shifter of the present invention, which has solved the above-mentioned problems, is disposed on a machine base and is detachably connected to a switching valve connected to a cargo handling hydraulic line and the switching valve. And a shifter unit,
It comprises a flexible hose including a forward / reverse rotary hydraulic motor, and a socket attached to the output shaft of the hydraulic motor and engageable with the screw shaft.

[0008]

In the fork shifter having such a structure, the fork gap can be changed and adjusted only by connecting the shifter unit to the switching valve on the machine base side and connecting the socket to the screw shaft. Therefore, each of the machine bases need only be provided with a switching valve as an element for adjusting the fork interval, and moreover, the movement of the forks can be adjusted while watching it at hand, and the operability becomes extremely easy.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to FIGS. As shown in FIG. 1, the forklift 11 including the fork shifter of the present invention has a control valve 1
2. A hydraulic unit 15 having a hydraulic pump 13 and a tank 14 is provided, and the mast cylinder 16 and the tilt cylinder 1 are driven by the hydraulic energy of the hydraulic unit 15.
7 etc. are driven. A three-position, four-joint switching valve 18 provided in this embodiment is connected to the hydraulic unit 15 as shown in FIG. The switching valve 18 is, for example, the floor 19 of the machine base 19.
It is attached to the side of a.

In FIG. 2, the discharge line 20 of the hydraulic pump 13 is connected to the control valve 12, and the return line 21 from the discharge line 20 to the tank 14 is connected to the switching valve 18. There is. A shifter unit 25 as a tool for adjusting the distance between the pair of forks is connected to the switching valve 18. Shifter unit 2
5 comprises a flexible hose 22, a hydraulic motor 23 connected between the respective one ends of the flexible hose 22, and a socket 24 attached to an output shaft 23a of the hydraulic motor 23. The shifter unit 25 is a flexible hose 2
It is detachable by 2.

On the other hand, the pair of forks 2 is shown in FIGS.
As shown in FIG.
The lower finger bar 28 by the lower hook portion 2b.
Is engaged with. Then, in the middle of the upper finger bar 1 and the lower finger bar 28, the screw shaft 3 that is bridged between the left and right frames 31 and 32 of the backrest 30 is installed in parallel.

The screw shaft 3 projects outward by a predetermined amount from the bracket 35 fixed to the left frame 31, for example. The protrusion 36 has, for example, a rectangular shape,
The shape corresponds to the shape of the fitting hole 24a of the socket 24. The socket 24 can be connected to the protrusion 36 by, for example, a rotating operation. The screw shaft 3 is divided into a right screw 3a and a left screw 3b at the center, and each fork 2 is movable on the screw shaft 3 via a ball nut 34 with the center as a boundary.

According to such a configuration, when the adjustment of the spacing between the forks 2 is performed, the flexible hose 22 of the shifter unit 25 is switched to the machine base side while the engine of the forklift 11 is operating. By connecting to the valve 18 and connecting the socket 24 to the protrusion 36 of the screw shaft 3, it is possible to adjust the fork spacing.

In this case, when the screw shaft 3 is rotated clockwise, as shown in FIG.
The right fork 2 is moved in the right direction E by a, and the left fork 2 is moved in the left direction F by the left screw 3b. Therefore, when the hydraulic motor 23 is rotated right, the space between the forks 2 is widened, and when the hydraulic motor 23 is rotated left, the space between the forks 2 is narrowed.

The direction of rotation of the hydraulic motor 23 depends on the switching valve 18
You can switch the position of the spool. This switching can be operated by a switching lever 37 (see FIG. 1) attached to the main body case of the switching valve 18, as shown in FIG. 1, for example. That is, the spool takes the D or C position by operating the switching lever 37. When the C position is set, a counterclockwise flow of pressure oil occurs in FIG. 1 to rotate the output shaft 23a, for example, to the right, whereby the screw shaft 3 is rotated to the right and the fork interval can be expanded. . Also, the spool is D in FIG.
When the position is taken, a clockwise flow of pressure oil is generated in the flexible hose 22 and the output shaft 23a is rotated counterclockwise, whereby the screw shaft 3 is rotated counterclockwise and the fork interval can be narrowed. .
The adjustment of the fork interval can be performed near the forks, and there is an advantage that reliable adjustment can be performed.

As described above, in the fork shifter of the present invention, it is possible to change and adjust the fork interval without requiring a skill, only by simple attachment / detachment work and lever operation. In addition, since the pressure oil in the hydraulic line is directly used as power, the fork lift can be efficiently adjusted without operating the forklift. A solenoid valve may be used as the switching valve 18. In this case, the changeover lever 37 is a direction changeover switch for the current supplied to the solenoid. Further, the switching lever 37 can be provided on the hydraulic motor 23 of the shifter unit 25. However, in this case, a solenoid valve is used as the switching valve 18, and it is necessary to connect electric wiring in addition to the wiring of the flexible hose 22.

[0017]

As described above, according to the present invention, since the fork shifter is detachably attached to the switching valve mounted on the machine side, the machine side element is only the switching valve. In a facility equipped with a large number of units, if one shifter unit is already installed, that shifter unit can be used for all machine bases, which has the effect of improving economic efficiency.

[Brief description of drawings]

FIG. 1 is an overall view of a forklift including a fork shifter according to the present invention.

FIG. 2 is a circuit diagram showing a hydraulic system of the fork shifter.

FIG. 3 is a perspective view for explaining a change and adjustment operation of a fork gap according to the present invention.

FIG. 4 is a front view illustrating a fork shifter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Upper finger bar, 2 ... Fork, 3 ... Screw shaft, 11 ... Forklift, 12 ... Control valve, 13 ... Hydraulic pump, 14 ... Tank, 15 ... Hydraulic unit, 18 ... Switching valve, 19 ... Machine stand, 20 ... Discharge line,
21 ... Return line, 22 ... Flexible hose, 23 ... Hydraulic motor, 24 ... Socket, 25 ... Shifter unit.

Claims (1)

[Claims] 1. A forklift mounted on a machine base in a forklift configured to adjust a gap between a pair of forks suspended on a finger bar by rotation of a screw shaft inserted in the forks, and a hydraulic pipe for cargo handling. A switching valve connected to the passage and a shifter unit detachably connected to the switching valve, the shifter unit including a flexible hose including a forward / reverse rotary hydraulic motor, and an output shaft of the hydraulic motor. And a fork shifter that is attached to the socket and is capable of engaging with the screw shaft.