JP2001026399A - Unbalanced load detector in cargo handling gear of forklift truck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an appreciable unbalanced load detector that detects an unbalanced load in the cargo handling gear of forklift trucks. SOLUTION: This unbalanced load detector in the cargo handling gear of forklift trucks comprises fixed blocks 30 long from side to side fixed to a mast, and right and left swing blocks 32 long from side to side disposed under the fixed blocks 30 for pivotal swing motion and fixedly connected with ends on one side of right and left lift chains 21. Compressive load cells 36 for detecting compressive force are sandwiched between the fixed blocks 30 and the swing blocks 32 in laterally symmetric fashion. The position where each compressive load cell 36 is mounted is on the same side of the swing block 32 with respect to the pivot as the position where the one end of the lift chain 21 is fixed. Both mounting and fixing positions are set so that the distance between the pivot and the mounting position is longer than that between the pivot and the fixing position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an unbalanced load detecting device for detecting an unbalanced load in a lateral direction of a vehicle body when a load is placed on a fork claw in a forklift truck cargo handling device.

[0002]

2. Description of the Related Art Forklift truck cargo handling equipment
A mast is provided at a front portion of the vehicle body, and the mast includes a pair of left and right outer masts and a pair of left and right inner masts inside the mast, and the inner mast is moved up and down with respect to the outer mast.

[0005] Lift cylinders are provided on the left and right along the outer mast and the inner mast, respectively.
This lift cylinder has its cylinder rod fixed to the inner stay connecting the upper parts of the left and right inner masts.

On the other hand, there is provided a lift bracket which can be moved up and down along the inner mast, and a pair of left and right fork claws is attached to the lift bracket.

[0005] A substantially L-shaped chain stopper is attached to the left and right of the lower part of the outer stay connecting the upper parts of the left and right outer masts, and a chain wheel is attached to each of the upper parts of the inner mast. Then, one end is fixed to a chain stopper, and the other end is fixed to a lift bracket.

The inner mast moves up and down with respect to the outer mast by the expansion and contraction of the lift cylinder.
The lift bracket and the fork pawl are moved up and down via the left and right lift chains by the up and down movement of the inner mast.

In such a cargo handling device for a forklift truck, there has been known an unbalanced load detecting device for detecting an unbalanced load in a lateral direction of a vehicle body when a load is placed on a fork claw. As shown in FIG. 1, the swing bracket 3 is provided with a swing board 3 on which an upper portion is pivotally mounted on the front side of a lift bracket 1 and which can swing back and forth, and a fork claw 2 is mounted on the front side. The compression force is detected by sensors 4 attached to the left and right sides of the lift bracket 1, and the eccentric load in the vehicle body left-right direction is detected from the difference between the detection values of the left and right sensors 4.

[0008]

In the case of a conventional unbalanced load detecting device in a forklift truck cargo handling device, a swing board must be provided on the front side of a lift bracket, and this portion becomes large or heavy. In addition, there is a problem that wiring increases to the sensor attached to the lift bracket, and the wiring extending from the vehicle body becomes complicated because the lift bracket moves up and down. An object of the present invention is to solve these problems.

[0009]

According to the present invention, a mast and a lift cylinder are provided at a front portion of a vehicle body, and a lift bracket which can be moved up and down along the mast is provided. In the forklift truck loading and unloading device, each of which has left and right lift chains for fixing the other end and fixing the other end to the lift bracket, and lifting and lowering the lift bracket and the fork claws via the left and right lift chains by the expansion and contraction movement of the lift cylinder, Equipped with a horizontal slender fixed block that is fixed to the mast and lift cylinder side, a horizontal slender swing block that can swing freely around a fulcrum below this fixed block and fixes one end of each of the left and right lift chains to the left and right Compressive force is detected between the swing block and the fixed block. Compressed load cells are mounted symmetrically to each other, and the fixing position for fixing one end of the lift chain in the swing block and the mounting position for mounting the compression type load cell are arranged on the same side with respect to the fulcrum, and mounted from the fulcrum. An unbalanced load detection device in a loading and unloading device of a forklift truck in which an attachment position and a fixing position are positioned so that a distance to a position is larger than a distance from a fulcrum to a fixing position.

[0010]

According to the present invention, since an unbalanced load detecting device for detecting an unbalanced load is not provided on the lift bracket side which moves up and down along the mast, it is possible to eliminate the problem of large size or weight increase on the lift bracket side. In addition, since there is no wiring from the vehicle body side, it is possible to greatly reduce wiring complexity and disconnection.

In addition, in this eccentric load detecting device,
The fixed position of the lift chain in the swing block and the mounting position of the compression type load cell are located on the same side of the fulcrum, so that the distance from the fulcrum to the mounting position is larger than the distance from the fulcrum to the fixed position. Therefore, the force acting on the load cell is reduced by the leverage of the pulling force of the lift chain, reducing the load on the load cell, allowing a small load cell to be used without using a large load cell, and the detection accuracy here Price and soaring prices can be suppressed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of an eccentric load detecting device in a forklift truck cargo handling device according to the present invention will be described. As shown in FIGS. 2 and 3, the cargo handling device of the forklift truck includes a mast 10 at the front portion of the vehicle body, and the mast 10 includes a pair of left and right outer masts 11 and a pair of left and right inner masts 12 inside the mast. And inner mast 12 is outer mast 11
It is designed to move up and down.

A lift cylinder 13 is provided on each of the left and right sides along the outer mast 11 and the inner mast 12, and the lift cylinder 13 has its cylinder rod 14 fixed to an inner stay 15 connecting the upper parts of the left and right inner masts 12. ing.

On the other hand, there is provided a lift bracket 16 which can be moved up and down along the inner mast 12, and a pair of left and right fork claws 17 is attached to the lift bracket 16.

A substantially L-shaped chain stopper 19 is attached to the lower part of the outer stay 18 connecting the upper parts of the left and right outer masts 11 respectively, and a chain wheel 20 is attached to each of the upper parts of the inner mast 12. Lift chains 21 are attached to the left and right sides, each of which is hung on a chain wheel 20 and one end is fixed to the chain stopper 19 side, and the other end is fixed to the lift bracket 16.

The inner mast 12 is moved up and down with respect to the outer mast 11 by the expansion and contraction movement of the lift cylinder 13, and the lift bracket 16 and the fork pawl 17 are moved up and down via the left and right lift chains 21 by the up and down movement of the inner mast 12. I am trying to do it.

FIG. 4 and FIG. 5 show an unbalanced load detecting device for detecting an unbalanced load in the left-right direction of the vehicle body when a load is placed on the fork pawls 17 in the forklift truck cargo handling device thus configured. As described above, the left and right fixed blocks 30 fixed to the left and right chain stoppers 19 attached to the outer stay 18 of the outer mast 11 are respectively provided on the left and right sides. They are arranged so as to be directed symmetrically to the left and right centers.

Below the left and right fixed blocks 30, there are provided left and right swing blocks 32 which can be vertically swung about a shaft 31 which is disposed on the left and right outer sides and extends horizontally. The swing block 32 has a substantially slender horizontal plate shape having substantially the same shape as the fixed block 30,
The left and right swing blocks 32 are also arranged so as to be directed symmetrically to the left and right centers.

On the other hand, through holes 33 are formed in the chain stopper 19, the fixed block 30, and the oscillating block 32 so as to communicate vertically, and one end of the lift chain 21 passes through the through holes 33 from above and swings. By fixing the lower end of the lift chain 21 to the swing block 32 with the nut 34 below the moving block 32, one end of the lift chain 21 is fixed to the chain stopper 19 via the fixed block 30 and the swing block 32.

A recess 35 is formed on each of the upper surfaces of the left and right swing blocks 32 on the left and right sides, and a compressive load cell 36 for detecting a compressive force is accommodated in the recess 35. Is brought into contact with the lower surface of the fixed block 30, whereby the compression-type load cell 36 is symmetrically mounted between the swing block 32 and the fixed block 30 in a sandwiched state.

At this time, the rocking position of the swing block 32 at which one end of the lift chain 21 is fixed and the mounting position B at which the compression type load cell 36 is mounted between the rocking block 32 and the fixed block 30 are moved. Block 3
2 is disposed on the left and right inner sides, that is, on the same side with respect to a fulcrum C, which is a point at which the 2 swings. Further, the distance α from the fulcrum C to the mounting position B is defined as the distance β from the fulcrum C to the fixing position A.
The mounting position B and the fixing position A are positioned so as to be larger, for example, about five times.

[0022] As a result, the tensile force of the lift chain 21 caused by the luggage placed on the fork claw 17 _{W B}
By now the swing block 32 swings up and down the shaft 31 as a fulcrum with respect to the fixed block 30, the compression force W _A is to act on the load cell 36 by swinging of the swing block 32, in the load cell 36 I would like to detect the compression force W _a. As shown in FIG. 6, the compression force detected by the left and right load cells 36 is input to the on-vehicle controller 37, and the left and right An eccentric load in the left-right direction of the vehicle body is detected from a difference between the right and left compression forces detected by the load cell 36, and this eccentric load is displayed on a display panel 38, for example, beside an operation meter.

The on-vehicle controller 37 can also detect the load when a load is placed on the fork pawl 17 by adding the compression force detected by the left and right load cells 36. This prevents overload and the like.

With such a configuration of the eccentric load detecting device for detecting an eccentric load in the lateral direction of the vehicle body when a load is placed on the fork pawl 17, a heavy load is placed on the front side of the conventional lift bracket. Eccentric load can be detected without providing a swinging board, which eliminates the problem of the lift bracket 16 and the fork claw 17 becoming large or heavy, and furthermore, wiring from the vehicle body side. By eliminating the problem, it is possible to prevent the wiring from becoming complicated, to largely eliminate the disconnection and the like, and to make the wiring and the like excellent in external appearance.

Further, the fixing position A of the lift chain 21 in the swing block 32 and the mounting position B of the compression type load cell 36 are arranged on the same side with respect to the fulcrum C, and the distance α from the fulcrum C to the mounting position B is determined. by the fulcrum C was larger 5 times than the distance β to the fixing position a, the compression force W _a to be detected by the load cell 36, with respect to the tensile force W _B of the lift chain 21 at fixed positions a location, next It is expressed by the following equation.

[0026] _{W A = (β / α)} × W B α = 5, β = 1 ∴W A = 1/5 × W B

[0027] In the load cell 36, the compression force _{W A} by the action of leverage to the tensile force _{W B} of the lift chain 21 decreases the force of the order of 1/5. Thus, the price of the detection accuracy is poor and the load cell itself as a large load cell is very expensive, smaller force of, for example, 1/5 times the tensile force W _B of the lift chain 21 as described above the load cell 36 By working on the load cell 36
Thus, a small load cell can be used without using a large load cell, and a decrease in detection accuracy and an increase in price can be suppressed.

In the above-described offset load detecting device,
Although the shaft 31 is used as a member interposed between the fixed block 30 and the swing block 32 and swinging the swing block 32, the invention is not limited to this. For example, two or a plurality of spheres may be used instead of the shaft. It may be used.

Next, a description will be given of a second embodiment of the unbalanced load detecting device in the forklift truck cargo handling device according to the present invention. In the first embodiment described above, the lift cylinder 13 is used as a material handling device for a forklift truck.
However, instead of this, one lift cylinder 13 is provided at the left and right center. Then, a pair of left and right chain wheels 20 is attached to the cylinder rod 14 of the lift cylinder 13, hung on the chain wheel 20 and one end is fixed to the cylinder tube 40 side of the lift cylinder 13, and the other end is attached to the lift bracket 16. Lift chain 2 sticking
1 is provided on each of the left and right sides.

As shown in FIG. 7, the unbalanced load detecting device includes a cylinder tube 4 of a lift cylinder 13.
The fixed block 30 is fixed to the upper portion of the lift cylinder 13. The fixed block 30 has a horizontally elongated plate shape on the left and right sides, and is arranged symmetrically with respect to the cylinder tube 40 of the lift cylinder 13.

Below the fixed block 30, there are provided left and right swing blocks 32, which are arranged on both left and right outer sides, and which can swing up and down about a shaft 31 extending in the front-rear direction and horizontally. The moving block 32 has a substantially slender plate shape, and the left and right swing blocks 32 are arranged so as to face each other to the left and right centers and to be symmetrical.

On the other hand, left and right through holes 33 are formed in the fixed block 30 and the left and right swing blocks 32 and communicate with each other vertically. One end of each of the left and right lift chains 21 penetrates through each of the through holes 33 from above. The one end of the lift chain 21 is fixed to the cylinder tube 40 side of the lift cylinder 13 via the fixed block 30 and the swing block 32 by being fixed to the swing block 32 with a nut 34 below the swing block 32. Become like

Then, similarly to the first embodiment, the compression type load cell 36 is mounted symmetrically between the swing block 32 and the fixed block 30 in a left-right state.
The compression force is detected in the load cell 36.

With this configuration, as in the case of the first embodiment described above, the problem that the portions of the lift bracket 16 and the fork pawl 17 become large or the weight increases is eliminated, and the wiring is complicated. It is possible to prevent disconnection and the like, and to largely eliminate disconnection and the like, and to make the wiring and the like excellent in external appearance.
Moreover, since the small force to tension force W _B of the lift chain 21 acts on the load cell 36, load cell 3
6 can be reduced, a small load cell can be used without using a large load cell, and a decrease in detection accuracy and a rise in price can be suppressed.

In the above-described first or second embodiment of the eccentric load detecting device, a compression type load cell 36 is provided between the swing block 32 and the fixed block 30 from the fulcrum C.
The mounting position B and the fixing position A are set so that the distance α from the fulcrum C to the fixing position A for fixing one end of the lift chain 21 in the swing block 32 is approximately five times the distance β from the fulcrum C to the mounting position B. However, the present invention is not limited to this, and the distance α from the fulcrum C to the mounting position B is determined from the fulcrum C to the fixing position A.
The attachment position B and the fixing position A may be positioned so as to be larger than the distance β to the load cell 36, and the positions may be arbitrarily changed according to the load cell 36 to be used. Further, in the above-described first or second embodiment, the load cell 36 side of the eccentric load detection device is provided in the center of the left and right masts 10 inward, but the present invention is not limited to this. The direction can be arbitrarily changed as long as it is held.

[0036]

According to the present invention, since an unbalanced load detecting device for detecting an unbalanced load is not provided on the side of the lift bracket which moves up and down along the mast, it is possible to eliminate the problem of a large size or an increase in weight on the side of the lift bracket. In addition, since there is no wiring from the vehicle body side, wiring becomes complicated,
Disconnection and the like can be largely eliminated, and safety during operation can be improved.

In addition, in this offset load detecting device,
The fixed position of the lift chain in the swing block and the mounting position of the compression type load cell are located on the same side of the fulcrum, so that the distance from the fulcrum to the mounting position is larger than the distance from the fulcrum to the fixed position. Therefore, the force acting on the load cell is reduced by the leverage of the pulling force of the lift chain, reducing the load on the load cell, allowing a small load cell to be used without using a large load cell, and the detection accuracy here Therefore, it is possible to suppress an increase in price and a rise in price, and it is possible to provide an extremely favorable eccentric load detecting device.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a conventional offset load detection device.

FIG. 2 is a front view of a forklift truck cargo handling device.

FIG. 3 is a side view of the cargo handling device of the forklift truck.

FIG. 4 is an explanatory front view showing an eccentric load detection device according to the present invention.

FIG. 5 is an explanatory side view showing an eccentric load detecting device according to the present invention.

FIG. 6 is a schematic configuration diagram of an eccentric load detection device according to the present invention.

FIG. 7 is an explanatory front view showing another offset load detecting device according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Lift bracket, 2 ... Fork claw, 3 ... Swing board, 4 ... Sensor, 10 ... Mast, 11 ... Outer mast, 12 ... Inner mast, 13 ... Lift cylinder, 14
... Cylinder rod, 15 ... Inner stay, 16 ... Lift bracket, 17 ... Fork claw, 18 ... Outer stay,
19: chain stopper, 20: chain wheel,
21 ... lift chain, 30 ... fixed block, 31 ...
Shaft, 32: swing block, 33: through hole, 34: nut, 35: recess, 36: load cell, 37: onboard controller, 38: display panel, 40: cylinder tube.

Claims (1)

[Claims] 1. A mast 10 and a lift cylinder 13 are provided at a front portion of a vehicle body, and a lift bracket 16 that can be moved up and down along the mast 10 is provided. A fork pawl 17 is attached to the lift bracket 16 and one end is fixed. The lift cylinder 13 includes left and right lift chains 21 each having the other end fixed to the lift bracket 16.
In a forklift truck loading and unloading device in which the lift bracket 16 and the fork pawl 17 are moved up and down via the left and right lift chains 21 by the expansion and contraction movement of the forklift truck, there is provided a horizontally elongated fixing block 30 for fixing the mast 10 and the lift cylinder 13 side. Below the fixed block 30, there are left and right horizontal and narrow swing blocks 32 that are swingable about a fulcrum and fix one end of each of the left and right lift chains 21, between the swing block 32 and the fixed block 30. Compressive load cells 36 for detecting the compressive force are mounted symmetrically to each other, and a fixing position for fixing one end of the lift chain 21 in the swing block 32 and a mounting position for mounting the compressive load cells 36 are used as fulcrums. And the distance from the fulcrum to the mounting position An unbalanced load detection device in a forklift truck loading and unloading device, wherein the mounting position and the fixing position are positioned so as to be larger than the distance from the fulcrum to the fixing position.