JPH021077B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a hydraulic piping structure in a mast system of a material handling vehicle such as a forklift truck.

Conventional technology In this type of conventional hydraulic piping structure, a single-acting piston is used for the front cylinder 2 provided on the inner mast 1, and it is equipped with a return pipe, and there are two pipes, a lift pipe 4 and a return pipe 5. However, due to the compactness of the mast, multiple pipes are required for both lift and return pipes 4 and 5.
It was necessary to divide the mast into left and right sides.

Especially when the cargo handling vehicle becomes large, there are multiple split hoses.

Problems to be Solved by the Invention For this reason, the visibility inside the mast was extremely poor due to the piping. In addition, the front cylinder 2 of the three-tier mast was located at the mast center, which obstructed the view when unloading cargo near the ground.

In addition, because the diameters of the lift and return piping 4 and 5 are large, the pulley diameter of the pulley 7 becomes large, making it impossible to raise the position of the outer head stay 8, resulting in poor driving visibility (Fig. 5, illustration). reference).

The present invention was developed in view of the above circumstances, and its purpose is to reduce the obstruction of visibility by piping inside the mast by half, and also to raise the position of the outer head stay, thereby improving the running visibility. An object of the present invention is to provide a piping structure in a mast device of a cargo handling vehicle that can be satisfactorily constructed.

Means and Effects for Solving the Problems In order to achieve the above object, the present invention has an outer mast 10, an intermediate mast 11, and an inner mast 12, and the inner mast 12 has a front cylinder 16 for raising and lowering a fork. In the mast device of a cargo handling vehicle provided with
and the lower pulley 20 are tilted in opposite directions, and the upper pulley 19 lifts the lift side piping 2 of the front cylinder 16.
1 or the return side piping 23, and the other piping is supported by the lower pulley 20, which reduces the obstruction of the visibility by the piping inside the mast by half and improves the running visibility.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 5. 10 is an outer mast, an intermediate mast 11 is provided on the outer mast 10 so as to be movable up and down, an inner mast 12 is provided on the intermediate mast 11 so as to be movable up and down, and a fork 13 is attached to the inner mast 12.
is provided so that it can be moved up and down.

A rear cylinder 14 is attached to the outer mast 10, and a piston rod 15 of the rear cylinder 14 is connected to the upper part of the intermediate mast 11. Further, a front cylinder 16 is attached to the inner mast 12, and a sprocket 18 is pivotally supported on a piston rod 17 of the front cylinder 16. Further, upper and lower pulleys 19 and 20 are pivotally supported on the upper and lower parts of the intermediate mast 11.

The upper pulley 19 is inclined inward with respect to the center line T of the vehicle, and the lower pulley 20 is inclined outward with respect to the center line T of the vehicle.
The upper and lower pulleys 19 and 20 are in a crossed state as shown in FIG. 4 when viewed from above.

The lift side piping 21 of the front cylinder 16 is connected to the joint part 22 of the outer mast 10 after being hung on the upper pulley 19, and the return side piping 23 of the front cylinder part 16 is connected to the joint part 22 of the outer mast 10 after being hung on the lower pulley 20. It is connected to the joint portion 24 of the outer mast 10. This joint portion 22 is connected to a hydraulic pressure supply source 25 via a conduit 26, and the joint portion 22 communicates with a tank 27.

The chain 28 which is engaged with the fork 13 is engaged with the sprocket 18 and is then engaged with the intermediate mast 11.

Therefore, by supplying hydraulic pressure from the hydraulic pressure supply source 25 to the front cylinder 16 via the lift-side piping 21 and returning oil to the tank 27 via the return-side piping 23, the front cylinder 16 is extended and the sprocket is extended. 18. Raise the fork 13 via the chain 28.

In the piping structure described above, the upper and lower pulleys 1
9 and 20 support the lift side piping 21 and the return side piping 23, and the obliqueness of the upper and lower pulleys 19 and 20 reduces the obstruction of the view by the piping inside the mast by half.

Further, since the upper pulley 19 supports only the lift side pipe 21, the diameter of the upper pulley 19 can be made small. For this reason, the position of the outer head stay 30 can be raised by 1 compared to the conventional one, and the driving visibility is improved (see FIG. 5B).

Effects of the Invention As described in detail above, the piping structure in the mast device of a cargo handling vehicle according to the present invention has the advantage that the intermediate mast 11
The upper pulley 19 and the lower pulley 20 are respectively pivotally supported, and the upper pulley 19 and the lower pulley 20 are tilted in opposite directions. Since the lower pulley 20 supports one of the piping and the other piping is supported by the lower pulley 20, the obstruction of the view by the piping inside the mast can be halved, and the upper pulley 19 can only support one piping. As a result, the pulley diameter of the upper pulley 19 can be made smaller, and the outer head stay position can be raised accordingly, making it possible to improve the running visibility.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the configuration of one embodiment of the present invention, Fig. 2 is a view taken from the direction of Fig. 1, Fig. 3 is a view taken from the direction of Fig. 1, and Fig. 4 is a diagram according to the present invention. A plan view of a mast device equipped with a hydraulic piping structure, FIG. 5 is an explanatory diagram of the height change of the outer head stay, FIG. 6 is an explanatory diagram of the hydraulic piping structure in the mast device of a conventional cargo handling vehicle, and FIG. The same front view and FIG. 8 are the same plan views. 11 is an intermediate mast, 19 is an upper pulley, 20 is a lower pulley, 21 is a lift side piping, and 23 is a return side piping.

Claims (1)

[Claims] 1 Outer mast 10, intermediate mast 11 and inner mast 1
In the mast device for a cargo handling vehicle, the inner mast 12 is provided with a front cylinder 16 for raising and lowering the fork.
and a lower pulley 20 respectively, the upper pulley 19 and the lower pulley 20 are tilted in opposite directions, and the upper pulley 19 supports either the lift side piping 21 or the return side piping 23 of the front cylinder 16. A hydraulic piping structure in a mast device of a cargo handling vehicle, characterized in that the other piping is supported by a lower pulley 20.