JPH07172786A - Lift chain in lifting gear of fork-lift truck - Google Patents

Abstract

PURPOSE:To prevent any looseness in a lift chain from occurring by installing an elastic body in a side face of this lift chain extending over both outer and inner links. CONSTITUTION:An intermediate part 16b serving as a ring of a scissorlike helical spring 16 is attached to a pin 12 connecting an outer link 10 and an inner link 11 together, while each double end 16a straightening out is engaged with two adjacent pins 12 each. In this scissorlike helical spring 16 like this, such force as trying to be bent as in dogleg type works at all times, whereby a lift chain is also apt to be bent, so that such force as making its overall length so as to be contracted works at all times. Therefore, in time of operations, for example, at a time when a fork claw comes into contact with a pallet and a load or a top surface of a car's rear body as well as in the case where the fork claw has operated a lift cylinder further from a state of being contacted with a top face of the pallet or the like, even if looseness tries to be produced in the lift chain, the total length of this lift chain is made so as to be contracted by the spring 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lift chain in a lifting device for a forklift truck, and more particularly to a lift chain which prevents the lift chain from slackening.

[0002]

2. Description of the Related Art Conventionally, a lifting device for a forklift truck has a pair of left and right outer mast erected on the front part of the vehicle body.
The outer mast can be tilted back and forth around the lower side by a tilt cylinder mounted on the vehicle body, and a pair of left and right inner masts that can be vertically moved along the outer mast are erected, and can be vertically moved along the inner mast. A freely movable lifting body is provided, and a fork claw is attached to the lifting body. Further, one end of a lift chain is connected to the elevating body, and the lift chain is hooked on a rotating body provided on the upper part of the inner mast and the other end is connected to the outer mast. A lift cylinder, one of which is fixed to the outer mast and the other of which is fixed to the inner mast, is provided, and the elevating body is moved up and down via the lift chain by moving the inner mast up and down by expanding and contracting the lift cylinder. It is structured.

In such a forklift truck lifting device, the length is set so that the lift cylinder has the shortest stroke and the lift chain does not loosen when the fork pawl is brought into contact with the ground. , For example, when the fork pawl is attached to the upper surface of a pallet, luggage or a car carrier, the lift chain moves due to expansion and contraction of the lift cylinder, so the lift cylinder is further activated from the state where the fork pawl is attached to the upper surface of the pallet or the like. There is a risk that the lift chain may become loose. If this slack is large, there is a problem that the lift chain interferes with the parts inside the lifting device, for example, the cross members installed on the left and right inner masts, and is bitten there, so that the lifting motion of the lifting device cannot be performed.

In order to solve such a problem, conventionally,
Japanese Utility Model Publication No. 5-20799 and Japanese Utility Model Publication No. 1-121097.
The one described in Japanese Patent Publication is known. Fairness 5-2
In the one disclosed in Japanese Patent No. 0799, a chain bending prevention guard is provided at a connecting portion of a lift chain with an elevating body, and the chain bending prevention guard prevents the chain from bending, so that the lift chain becomes a part in the lifting device. It is designed to prevent interference and prevent biting.

In Japanese Utility Model Laid-Open No. 1-121097, a rotating body on which a lift chain is hooked is provided with a rotation urging means such as a spiral spring, and the rotation urging means elevates and lowers the lift chain. The tension between the body and the rotating body is always kept constant to eliminate the slack in the lift chain, thereby preventing the lift chain from being caught without interfering with the parts in the lifting device.

[0006]

The conventional lifting device for a forklift truck, which is disclosed in Japanese Utility Model Publication No. 5-20799, is provided with a chain bending prevention guard at the connecting portion of the lift chain with the lifting body. Although it prevents the chain from bending here, it is impossible to install this chain bending prevention guard on the entire lift chain, and the lift chain will be loosened at the part where this chain bending prevention guard is not provided. , There was a risk of interfering with the parts inside the lifting device.

Further, the one disclosed in Japanese Utility Model Laid-Open No. 1-121097 discloses a lift chain lifting / lowering body in which a space between the lift / lower body in the lift chain is pulled by a rotation urging means provided on the rotating body. Although the slack is eliminated between the rotary body and the rotary body, the lift chain may be loosened between the rotary body and the outer mast in the lift chain, which may interfere with the components in the lifting device. Further, since the rotating body is provided with the rotation biasing means, the structure of the rotating body becomes complicated, and the rotation of the rotating body in a normal state may not be accurately rotated by the rotation biasing means. The present invention aims to solve these problems.

[0008]

In order to solve the above problems, the present invention solves the above problems by providing an outer mast standing on the front part of a vehicle body, an inner mast that moves up and down along the outer mast, and a vertical move along the inner mast. Together with the ascending / descending body equipped with fork claws, one end is connected to the ascending / descending body, and the other end is connected to the outer mast via the rotating body provided at the upper part of the inner mast and the other end is alternately connected to the inner link. In a lifting device for a forklift truck, the lift chain comprises: a lift chain; and a lift cylinder, one of which is fixed to the outer mast and the other of which is fixed to the inner mast, and an elastic body is provided on a side surface of the lift chain across the outer link and the inner link. .

[0009]

[Operation] In the lift chain, the elastic body constantly exerts a force to shrink its entire length, so
For example, when the fork claws are attached to the upper surface of a pallet or luggage or the bed of a car, if the lift cylinder is further operated from the state where the fork claws are attached to the upper surface of the pallet or the like, even if the lift chain becomes loose, The elastic body causes the entire length of the lift chain to shrink,
Prevents the lift chain from becoming loose.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a lifting device for a forklift truck according to the present invention, as shown in FIG. 1, has a pair of left and right outer masts 2 provided upright on the front part of a vehicle body 1, and the outer masts 2 are mounted on the vehicle body 1. The tilt cylinder 3 tilts back and forth around the lower side, and a pair of left and right inner masts 4 are vertically arranged along the outer mast 2 and can be vertically moved along the inner mast 4. An elevating body 5 is provided, and a fork claw 6 is attached to the elevating body 5. Further, one end of a lift chain 7 is connected to the lifting body 5, the lift chain 7 is hooked on a pulley 8 which is a rotating body provided on the upper part of the inner mast 4, and the other end is connected to the outer mast 2. There is. And
One is fixed to the outer mast 2 and the inner mast 4 is fixed.
A lift cylinder 9 is fixed to the other, and the lift cylinder 9 is expanded and contracted to move the inner mast 4 up and down, whereby the lift body 5 is moved up and down via the lift chain 7.

As shown in FIGS. 2 and 3, the lift chain 7 is formed by alternately arranging outer links 10 and inner links 11 and connecting them with pins 12.
Each have an outer plate 13 on each side and a pair of intermediate plates 14 in the middle, and the inner link 1
1 has a set of three inner plates 15 on each side. Then, the inner plates 15 of the inner links 11 are arranged between the outer plates 13 and the intermediate plates 14 of the outer links 10, respectively, and the pins 12 are pierced there to connect the outer links 10 and the inner links 11 to each other. It is a combined structure.

Then, one end of the pin 12 is connected to the outer link 10 at a part between the lifting body 5 and the connecting portion of the lift chain 7 where the pulley 8 is hooked.
A plurality of scissor type helical springs 16 which are elastic bodies are provided so as to project from the outer plate 13 and to extend over the plurality of protruding pins 12. The scissor-type spiral spring 16 is made of an elongated wire material, has both ends 16a straightened, and has an intermediate part 16b wound once to have a ring having a size substantially the same as the outer diameter of the pin 12 of the lift chain 7. The outer link 1 has a middle portion 16b serving as a ring of the scissor type helical spring 16.
0 and the inner link 11 are attached to the pin 12, and both ends 16a of the scissor type helical spring 16 which are straight are engaged with the pins 12 on both sides. The plurality of scissor type helical springs 16 are provided adjacent to each other in the longitudinal direction of the lift chain. The pin 12 to which the intermediate portion 16b of the scissor type helical spring 16 is mounted is provided with a retaining pin such as a split pin or washer to prevent the scissor type helical spring 16 from coming off.

The scissor type helical spring 16 as described above is
A force that constantly bends in a dogleg shape acts, and accordingly, the lift chain 7 also tries to bend in the same manner, so that a force that causes the entire length of the lift chain 7 to always shrink is exerted. However, the weight of the lifting body 5 and the fork pawls 6 is normally applied to the lift chain 7, and the scissors-type helical spring 16 and the lift chain 7 are placed.
Is in a straight extended state, and the entire length of the lift chain 7 does not shrink.

By providing a plurality of scissor-type helical springs 16 on one of the side surfaces of the lift chain 7 in this manner, for example, when the fork pawl 6 is attached to the pallet, luggage, or the top surface of the cargo bed of a car. When the lift cylinder 9 is further operated from the state where the fork pawl 6 is in contact with the upper surface of the pallet or the like and the slack is about to occur in the lift chain 7, the weight of the lifting body 5 and the fork pawl 6 is added to the lift chain 7. As shown in FIG. 4, each of the scissor-type helical springs 16 bends in a dogleg shape because the tension is eliminated. Then, the lift chain 7 is also bent into a dogleg shape by the scissor type helical spring 16,
Since the entire length of the lift chain 7 is contracted, the lift chain 7 is prevented from being loosened. As a result, it is possible to prevent the lift chain 7 from being bitten without interfering with the components in the lifting device, and furthermore, without providing complicated components or having a complicated structure. It can be performed. When the lift chain 7 is contracted, the lift chain 7 is regularly bent in a V shape, so that the lift chain 7 can be contracted compactly without interfering with surrounding parts.

Further, in a normal state, the weight of the lifting body 5 and the fork pawl 6 is applied to the lift chain 7,
The scissors type helical spring 16 is in a straight extended state, and the lift chain 7 is also in a straight extended state. As a result, the operation of the lift chain 7 is not hindered.

Although the scissor type helical spring 16 is provided on one of the side surfaces of the lift chain 7 in the above-described embodiment, it may be provided on both of the side surfaces.
The lift chain 7 may be provided over the entire length instead of being provided on a part of the side surface. further,
Although the scissor-type spiral spring 16 is used as the elastic body in the above-described embodiment, a leaf spring bent in a dogleg shape is used to fix the middle part to the pin and both ends to both adjacent pins. Alternatively, both ends may be fixed to the outer link 10 and the inner link 11, respectively. Further, the lift chain 7 is not limited to the one described in the above embodiment, and a general roller type chain or the like may be used.

[0017]

In the lift chain, the elastic body constantly exerts a force to shrink the entire length of the lift chain, so that the lift chain is not loosened. Therefore, it is possible to prevent the lift chain from interfering with the components in the lifting device, and prevent biting or the like. Further, unlike the conventional case, the lift chain is simply provided with an elastic body without providing complicated parts such as a prevention guard or providing a rotating body with a rotation urging means to form a complicated structure. With a simple structure, the lift chain can be prevented from loosening. Further, since the lift chain has a simple structure in which only an elastic body is provided, it can be provided at low cost.

[Brief description of drawings]

FIG. 1 is a side view of a lifting device for a forklift truck.

FIG. 2 is a side view of a lift chain according to the present invention.

FIG. 3 is a front view of a lift chain according to the present invention.

FIG. 4 is a side view showing a retracted state of the lift chain according to the present invention.

[Explanation of symbols]

1 ... vehicle body, 2 ... outer mast, 3 ... tilt cylinder, 4
... Inner mast, 5 ... Lifting body, 6 ... Fork claw, 7 ... Lift chain, 8 ... Pulley, 9 ... Lift cylinder, 10
... outer link, 11 ... inner link, 12 ... pin, 13 ... outer plate, 14 ... intermediate plate, 15 ... inner plate, 16
... scissor type helical springs, 16a ... both ends, 16b ... intermediate part.

Claims (3)

[Claims] 1. An outer mast 2 provided upright on a front portion of a vehicle body 1.
An inner mast 3 that moves up and down along the outer mast 2, an elevating body 5 that moves up and down along the inner mast 3 and is provided with a fork claw 6, and one end of the inner mast 4 is connected to the inner mast 4 An outer link 10 having the other end connected to the outer mast 2 via a rotating body provided on the upper part.
A lift chain for a forklift truck, comprising: a lift chain 7 formed by alternately connecting an inner link 11 and an inner link 11; and a lift cylinder 9 fixed to the outer mast 2 and the other fixed to the inner mast 4. An elastic body is attached to the side surface of the lift chain to connect the outer link 10
A lift chain for a lifting device for a forklift truck, which is provided across the inner link 11 and the inner link 11. 2. As the elastic body, a scissor type helical spring 16 is used which is formed by winding the intermediate portion 16b once to form a ring and straightening both end portions 16a, and the intermediate portion 16b serving as the ring is formed. 2. Both ends 16a, which are mounted on the pin 12 and are straight, are provided so as to engage with the pins 12 on both sides, respectively.
A lift chain in the lifting device for a forklift truck described. 3. The lift chain in a lifting device for a forklift truck according to claim 2, wherein a plurality of the scissor type helical springs 16 are provided adjacent to each other in the longitudinal direction of the lift chain.