JP2000001296A - Sectional form of mast rail for fork lift - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the sectional form of a mast rail higher in rigity against a lateral bending and twisting without narrowing the field of vision from a driver seat. SOLUTION: The upper rear parts on both the sides of an inner mast rail 11 are in a lift roller sliding contact parts 15, 16 to support a lateral load by slide-contactly supporting the outer periphery of a rotating face of both the lift rollers, and a side roller sliding contact part which a side roller 7 comes into slide-contact with is formed at the about central position of the inner mast rail side face on the side (left side in figure) of a load carrying platform support bracket, and turned into a part for supporting a lateral load given from the load carrying platform support bracket together with the lift roller sliding contact part 15. The lift roller sliding part 16 provided behind a side flat face of the master rail side (right side in figure) is extended to the front position the same as that of the side roller sliding contact part positioned at the about center on the side of an opposite load carrying platform bracket to provide the lift roller sliding contact part 16 as a reinforcing part 17 for the side roller sliding contact part (oblique line in figure).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cross section of a mast rail of a forklift for preventing bending and torsion of the rail due to an eccentric load and for securing a front view.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, in a lifting mechanism 1 around a carrier 10 of a forklift,
The connection structure of the outer mast rail 2, the inner mast rail 3, and the carrier support bracket 4 is symmetrically arranged side by side. (FIG. 3 is a plan sectional view of only the right side).

In this figure, an inner mast rail 3 is slidable in a direction perpendicular to the paper surface inside an outer mast rail 2 which is a component to be installed on a vehicle body (not shown) (inward in a configuration where two are arranged side by side). , And a carrier support bracket 4 is slidably connected in the same direction inside the inner mast rail 3.

A lift roller 5 slides and supports the outer mast rail 2 from the outer mast rail 2 to the inner mast rail 3 in the front-rear direction, and a lift roller from the carrier support bracket 4 to the inner mast rail 3. 6 and the lateral roller 7 is mainly supported by the side rollers 7 in the lateral direction. More specifically, the two lift rollers 5 and 6 also have a configuration in which the two lift rollers 5 and 6 also support the lateral direction by sliding the outer circumference of the rotation surface toward the inner mast rail 3.

FIG. 4 is a plan sectional view of only the conventional inner mast rail 3 constituting the lifting mechanism 1. As shown in FIG.

In this figure, two hatched portions 8, 9 are shown.
Are located in sliding contact with the outer circumferences of the respective rotating surfaces of the two lift rollers 5 and 6, and are made thicker for the purpose of reinforcement as compared with the lateral width of the other inner mast rails.

In these thick portions for supporting the sliding contact, the rotation of the lift rollers 5, 6 is performed in order to avoid excessive lateral rubbing on the rotating surfaces of the lift rollers 5, 6 and to perform natural sliding contact support. A taper T having a clearance angle with respect to the surface, which is generally about 2 °, is provided in a direction gradually separating from the outer periphery to the inner periphery of the rotating surface.

[0008]

However, when a heavy object is loaded on the carrier 10, a lateral load is applied to the carrier due to a centrifugal force generated when the vehicle turns and a contact / collision from the lateral direction. In such a case, damage such as cracking or bending is likely to occur locally at the sliding contact portion between the side roller 7 on the side of the carrier support bracket 4 and the inner mast rail 3 in the conventional configuration, and the entire inner mast rail 3 In such a case, deformation such as twisting is likely to occur.

Since the inner mast rail 3 functions as a guide rail for guiding the sliding with the carrier support bracket 4 on the inner side, and functions as a guide rail for guiding the sliding with the outer mast rail 2 on the outer side. Straightness and parallelism are important factors in smooth lifting and lowering (lifting) of the loading platform. Therefore, the inner mast rail 3 itself should have a shape and configuration that is as rigid as possible against bending and torsion. The lifting mechanism also needs to be configured so as not to add a lateral load or a torsional moment.

Therefore, when the overall side width is increased to improve the strength of the inner mast rail 3 itself against lateral load, when the inner mast rail 3 is increased in lateral direction, the inward direction between the two masts to be fixed side by side (the sliding support direction In order to increase the thickness inevitably, lift rollers 5 and 6 and side rollers 7
At the same time, the carrier support bracket 4 moves inward, resulting in a problem that the field of view from the driver's seat is narrowed.

[0011] Such a problem has also occurred in, for example, an outer mast rail when a side roller is arranged on an inner mast rail.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a mast rail having a higher rigidity against bending and twisting in a lateral direction without narrowing the field of view from the driver's seat.

[0013]

To solve the above problems, the present invention is configured as follows.

First, in the present invention, in the mast rail of a forklift, the lateral width at a sliding contact portion with a side roller disposed on the side of a carrier support bracket is compared with the lateral width at other portions of the mast rail. It has a reinforcing part that protrudes toward the mast rail and is configured to be thick.

[0015] Accordingly, the loading support bracket including the side rollers is moved inward to reinforce the side roller sliding contact portion without any adverse effect such as narrowing the field of view from the driver's seat. The inner mast rail has a high cross section.

Further, the reinforcing portion has a width continuous with a sliding contact portion with a lift roller disposed on the outer mast rail on the rear side.

As a result, it is possible to simplify the cross-sectional shape since the conventional sliding contact portion of the lift roller can be extended, thereby improving rigidity while suppressing an excessive increase in weight. Becomes

Further, the reinforcing portion has a tapered surface in a direction gradually separating from the lift roller from the outer periphery to the inner periphery of the rotation surface of the lift roller and continuing to the sliding contact portion with the lift roller. I do.

As a result, natural sliding contact with the rotating surface of the lift roller is not interrupted.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a cross-sectional shape of an inner mast rail 11 according to an embodiment of the present invention.

In this figure, the inner mast rail 1
The cross-sectional shape of 1 is substantially U-shaped on the carrier support bracket side (left side in the figure), and the inner front portion 12 and the rear portion 13 are sliding portions with the carrier support bracket-side lift rollers and support the carrier. It is a portion that supports the load on the bracket in the front-rear direction. Further, a sliding portion 14 with the outer mast rail side lift roller is provided at the rear of the opposite outer mast rail side (right side in the figure).

The rear side of both sides of the inner mast rail 11 are lift roller sliding contact portions 15 and 16 for supporting the load in the lateral direction by slidingly supporting the outer circumference of the rotation surface of the lift rollers. The wall thickness is increased for the purpose of reinforcement in comparison with the lateral width of the inner mast rail.

A substantially center position of the side surface of the inner mast rail on the side of the carrier support bracket is a side roller sliding portion where the side roller 7 slides, and together with the lift roller sliding contact portion 15, supports a lateral load from the carrier support bracket side. Part.

In the same figure, the difference from the sectional shape of the conventional inner mast rail shown in FIG. 4 is that the lift roller sliding contact portion 16 provided on the rear side of the side on the outer mast rail side is substantially similar to the opposite carrier support bracket side. The configuration is such that a reinforcing portion 17 (hatched portion in the figure) of the side roller sliding contact portion is provided by extending to the same front position as the side roller sliding contact portion located at the center.

The lift roller sliding contact portion 16 on the outer mast rail side and the reinforcing portion 17, which is an extension thereof, are both provided with a taper T of about 2 ° and are continuous with each other. This enables natural sliding contact.

[0027] With the above-described structure, the load carrier support bracket is not moved inward while the side roller sliding contact portion is intensively and functionally reinforced from the opposite side of the outer mast rail. In other words, reinforcement against the lateral load of the inner mast rail 11 without deteriorating the field of view from the driver's seat is achieved.

In practice, the lift roller sliding contact portion 16 conventionally provided on the rear side surface on the outer mast rail side is used.
Is extended forward, so that the reinforcing portion 17 can be formed, so that a relatively simple cross-sectional shape can be obtained, thereby improving the lateral rigidity while suppressing an excessive increase in weight. .

Next, FIG. 2 illustrates the correlation between the center of gravity of each cross-sectional shape and the lateral load F applied from the side roller 7 in the conventional cross-sectional shape (a) and the cross-sectional shape (b) of the present embodiment. FIG.

First, in the conventional sectional shape shown in FIG. 2A, the lift roller sliding contact portion 1 on the outer mast rail side is used.
8 is arranged rearward, so that the side roller sliding contact portion 1
When the cross-sectional shape center of gravity 20 was located at a distance R behind the point 9 (lateral load application point), as shown in FIG.
The lift roller sliding contact portion 16 on the outer mast rail side is extended forward as the reinforcing portion 17 (hatched portion), so that the cross-sectional shape center of gravity 20 moves forward and is positioned closer to the side roller sliding contact portion.

For this reason, in the conventional configuration, by applying a lateral load F from the side roller sliding contact portion 19 (lateral load application point), the torsional moment M (F
× R) occurs over the entire length of the inner mast rail 3,
Although this was a major cause of impairing straightness and parallelism, in the present embodiment, the lateral load F is applied as it is as a simple lateral shear force, and as described above, the rigidity is sufficient in the present embodiment. Becomes

In the above-described embodiment, the present invention is applied to a two-stage mast type forklift in which the lifting mechanism 1 is composed of the outer mast rail 2, the inner mast rail 3, and the carrier support bracket 4. The present invention is not limited to this embodiment, and can be implemented in the following forms, for example.

The present invention is applied to an inner mast rail in a three-stage mast type forklift in which a lifting mechanism includes an outer mast rail, a middle mast rail, an inner mast rail, and a carrier support bracket 4. Further, the present invention is applied to the inner mast rail of a multi-stage mast type forklift having four or more stages.

In a two-stage mast type forklift, the present invention is applied to the outer mast rail adjacent to the inner mast rail when the side rollers are arranged on the inner mast rail instead of the carrier support bracket. In a three-stage mast type forklift, the present invention is applied to a middle mast rail when side rollers are arranged on an inner mast rail, and to an outer mast rail when side rollers are arranged on a middle mast rail. thing. Further, in a multi-stage mast type forklift having four or more stages, when a side roller is disposed on an arbitrary mast rail, the present invention is applied to a mast rail adjacent to the outside of the mast rail.

[0035]

As described above, by adopting the structure of the present invention in the lifting mechanism of a forklift, it is possible to improve the rigidity of the side roller sliding contact portion without lowering the field of view from the driver's seat. And a global effect such that the torsional moment generated over the entire inner mast rail can be removed and reduced.

As a result, the durability of the two masts arranged in parallel at the front both sides of the forklift against the lateral load is improved, and the straightness and the parallelism are maintained, so that the smooth sliding guide of the lifting can be performed permanently. It will be done.

[Brief description of the drawings]

FIG. 1 is a diagram showing a cross-sectional shape of an inner mast rail according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining the correlation between the center of gravity of each cross-sectional shape and the lateral load F applied from a side roller in the conventional cross-sectional shape (a) and the cross-sectional shape (b) of the present embodiment.

FIG. 3 is a plan sectional view of only the right side of a lifting mechanism incorporating an inner mast rail having a conventional sectional shape.

FIG. 4 is a view showing a cross-sectional shape of a conventional inner mast rail.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Lifting mechanism 2 Outer mast rail 3 Conventional inner mast rail 4 Carrier support bracket 5 Outer mast rail side lift roller 6 Carrier support bracket side lift roller 7 Side roller 8 Outer mast rail side lift roller sliding contact part 9 Carrier support bracket side lift Roller sliding contact portion 10 Loading platform 11 Inner mast rail of this embodiment 12 Front portion of loading platform support bracket side lift roller sliding portion 13 Rear portion of loading platform support bracket side lift roller sliding portion 14 Outer mast rail side lift roller sliding portion Reference Signs List 15 Lifting roller sliding contact part on carrier support bracket side 16 Lifting roller sliding contact part on outer mast rail 17 Reinforcement part of side roller sliding contact part 18 Lift roller sliding contact part on outer mast rail side 19 Side roller sliding contact part 20 Cross section weight Lateral load M torsional moment from the distance F side rollers Namerase' part from T tapered R lateral load application point to the cross section center of gravity

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[Procedure amendment]

[Submission date] June 11, 1999 (1999.6.1
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

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[Procedure amendment 2]

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[Correction target item name] 0015

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[0015] Accordingly, the loading support bracket including the side rollers is moved inward to reinforce the side roller sliding contact portion without any adverse effect such as narrowing the field of view from the driver's seat. a high now scan <br/> trail of the cross-sectional shape of.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0035

[Correction method] Change

[Correction contents]

[0035]

As described above, by adopting the structure of the present invention in the lifting mechanism of a forklift, it is possible to improve the rigidity of the side roller sliding contact portion without lowering the field of view from the driver's seat. and localized effects such, becomes the removal of torsional moment generated throughout Ma Strehl, two effects of global effects such reduction is enabled is exhibited simultaneously.

[Procedure amendment 4]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

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FIG.

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[Procedure amendment 6]

[Document name to be amended] Drawing

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[Procedure amendment 7]

[Document name to be amended] Drawing

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Claims (3)

[Claims] In a mast rail of a forklift, a lateral width of a sliding contact portion with a side roller disposed on a side of a carrier support bracket is compared with lateral widths of other parts of the mast rail. An outer mast rail cross-sectional shape of a forklift, which has a reinforcing portion protruding to the side and is thick. 2. The mast rail cross section of a forklift according to claim 1, wherein the reinforcing portion has a width that is continuous with a sliding contact portion with a lift roller disposed on a side of the outer mast rail on the rear side. shape. 3. The reinforcing portion has a tapered surface in a direction gradually separating from the lift roller from the outer circumference to the inner circumference of the rotation surface of the lift roller and continuous with a sliding contact portion with the lift roller. The mast rail sectional shape of the forklift according to claim 2, characterized in that: