JP2001247298A - Mast structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mast structure mounted on a loading vehicle such as a fork lift, to be used as an outer mast of a single-stage mast or a multistage mast, and capable of exercising the sufficient strength to the twisting force with a simple structure. SOLUTION: This mast structure is composed of a frame member 2, an upper connecting member 3, a lower connecting member 4, a back face member 5 and a lower intermediate connecting member 6, in particular, left and right back face members 5 fixed to the lower connecting member 4 to form the approximately U-shape and fixed to lower back faces of the frame members 2, and the proper number of lower intermediate connecting members 6 for connecting the back face members are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a mast structure which is mounted on a cargo-handling vehicle such as a forklift and used as a single-stage mast or a multi-stage mast.

[0002]

2. Description of the Related Art Conventionally, as this type of mast structure, for example, a structure shown in FIG. 2 is known. The mast structure 50 includes left and right frame members 51, an upper connecting member 52 connecting upper portions of both frame members 51, a lower connecting member 53 connecting lower portions of both frame members 51, And an appropriate number of lower connecting members 54 for connecting the lower portions.

The lower connecting member 53 has a flat plate shape, and the upper connecting member 52 and the lower connecting member 54 have a substantially U-shaped plane.

[0004]

However, in such a device, the left and right frame members are simply connected by an appropriate number of connecting members, and therefore, as shown by an arrow in FIG. When a so-called torsional force is applied to move the material upward and the other frame material downward, respectively, the rigidity is low and sufficient strength cannot be exhibited. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has been made in order to solve the problem. The object of the present invention is to provide a simple structure capable of exerting sufficient strength against torsional force. In providing structure.

[0005]

According to the present invention, there is provided a mast structure comprising:
Basically, the left and right frame members, the upper connecting member that connects the upper parts of both frame members, the lower connecting material that connects the lower parts of both frame members, and the lower connecting member are fixed to form a substantially U-shape. The present invention is characterized in that it comprises left and right back members fixed to the lower back surfaces of the respective frame members and an appropriate number of lower connection members for connecting the two back members.

A back member is provided on the lower back surface of each frame member, and an appropriate number of lower connecting members are provided between the two back members. Therefore, even if a so-called twisting force is applied, in which one frame material is moved upward and the other frame material is moved downward, rigidity is increased and sufficient strength is obtained. Can be demonstrated.

[0007] The lower connecting member is a horizontal flat plate with a flat portion facing up and down, the back member is a vertical flat plate with a flat portion pointing left and right, and the lower connecting material is a flat plate portion pointing forward and backward. It is preferably a vertical flat plate. If you do this,
Since the lower connecting portion can be formed entirely of a flat plate and does not require bending as in the related art, the manufacturing can be made easier and the cost can be reduced.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a mast structure of the present invention.

The mast structure 1 includes a frame member 2, an upper connecting member 3,
The main part is constituted by the lower connecting member 4, the back member 5, and the lower connecting member 6, and is used as an outer mast of a single-stage mast or a multi-stage mast.

The frame material (mast frame material) 2 is a left and right material.
In this example, the groove 7 is elongated in the vertical direction and has a substantially groove-shaped section (channel type), and the grooves 7 are opposed to each other while being separated in the horizontal direction.

The upper connecting member 3 connects the upper portions of the two frame members 2 to each other. In this example, the upper connecting member 3 has a substantially U-shape in plan view, cuts the square member into a predetermined size and shape, and bends (substantially). (U-shaped), and both ends thereof are fixed by being welded to the upper outer surfaces of both frame members 2.

The lower connecting member 4 connects the lower portions of the two frame members 2 to each other. In this example, the lower connecting member 4 has a flat shape and is formed by cutting the plate material into a predetermined size and shape (planar substantially U-shaped). It is fixed by being flattened horizontally so as to face up and down and being welded to the lower back surface of both frame members 2.

The back member 5 is fixed to the lower connecting member 4 so as to form a substantially U-shape, and is fixed to the lower back surface of each frame member 2. In this example, the back member 5 has a flat plate shape. It is made by cutting to a predetermined size and shape, the plane portion is made vertical so as to face left and right, the front surface is welded to the lower back surface of both frame members 2, and the lower end is the lower connecting material 4 is fixed by being welded to the left and right upper surfaces.

The lower connecting member 6 is an appropriate number for connecting the two back members 5 and, in this example, comprises two upper and lower members for connecting the middle portions of the two back members 5 to each other. Each of them has a flat plate shape and is manufactured by cutting a plate material into a predetermined size and shape. The flat portion is made vertical so as to face front and rear, and both ends are welded to the back of both back members 5. Is fixed.

Although not shown, a tilt support for a tilt cylinder is provided on the upper outer surface of the back member 5 so as to partially extend over the frame member 2, and the lower connecting member 4 and the lower connecting member 6 are provided. Is provided with a mast support for being attached to the body of a cargo handling vehicle such as a forklift so as to be capable of tilting forward and backward, or a cargo handling device such as a forklift is provided on A mast support is provided for attaching to the vehicle body so that it can be tilted back and forth,
The lower connecting member 4 is provided with a tilt support for a tilt cylinder.

Next, the operation will be described based on such a configuration. On the lower rear surface of each frame member 2, a rear member 5 is provided, and between the two rear members 5, an appropriate number of lower connecting members 6 are provided. Since a substantially U-shaped frame is formed with the connecting member 4, even if a so-called torsional force is applied to move one frame member 2 upward and the other frame member 2 downward, the rigidity is large. And exhibit sufficient strength. Since the back member 5 is provided on the lower rear surface of each frame member 2, the lower side of each frame member is reinforced and the strength against buckling is increased. Since the lower connecting member 6 is provided between them using the back member 5, the lower connecting member 6 can be formed in a flat plate shape. For this reason, it is not necessary to perform a bending process as in the conventional case, so that the production becomes easier and the cost can be reduced.

In the above example, the frame member 2 has a substantially groove-shaped cross section. However, the present invention is not limited to this. For example, the frame member 2 has a substantially I-shaped cross section or a substantially J-shaped cross section.
It may be a mold or the like. In the above-described example, the frame member 2 does not include the intermediate connecting member that connects the intermediate portions. However, the present invention is not limited thereto. For example, the frame member may be provided. In particular, when the vertical length of the frame member 2 is long, it is desirable to make the above-described manner.
In the previous example, the lower connecting material 6 was two upper and lower members,
However, the present invention is not limited to this, and one or three or more may be used.

[0018]

As described above, according to the present invention, as described above,
The following excellent effects can be obtained. (1) It is composed of a frame material, an upper connecting material, a lower connecting material, a backing material, and a lower connecting material. In particular, it is fixed to the lower connecting material so as to form a substantially U-shape and is fixed to the lower rear surface of each frame material. Since the left and right back members and the appropriate number of lower connecting members for connecting the two back members are provided, sufficient strength against twisting force can be exhibited with a simple structure.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a mast structure of the present invention.

FIG. 2 is a perspective view showing a conventional mast structure.

[Explanation of symbols]

1, 50: mast structure, 2, 51: frame material, 3, 52: upper connecting material, 4, 53: lower connecting material, 5: back material, 6, 5
4 ... lower connecting material, 7 ... groove.

Claims (2)

[Claims] 1. A left and right frame member, an upper connecting member connecting upper portions of both frame members, a lower connecting member connecting lower portions of both frame members, and a lower connecting member fixed to form a substantially U-shape. A mast structure comprising left and right rear members fixed to the lower rear surface of each frame member and an appropriate number of lower connecting members connecting the two rear members. 2. The lower connecting member is a horizontal flat plate with a flat portion facing up and down, the back member is a vertical flat plate with a flat portion pointing left and right, and the lower connecting material is a flat plate having front and rear portions. The mast structure according to claim 1, wherein the mast structure is a vertical flat plate oriented toward the mast.