JPH09142798A - Forklift load sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a load sensor having performance equal to or more than a limit switch system in small space and a low cost. SOLUTION: In a forklift having a horizontal fork 1 to be vertically moved, an attaching metal fitting 2 is attached to the side face of the fork 1, a coil spring 3 is laid on the upper surface of the attaching metal fitting 2, a sheet metal switch 5 for detecting the existence of a load is inserted between the attaching metal fitting 2 and the coil spring 3 and the upper surface of the coil spring 3 is protruded upward more than the upper surface of the fork 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forklift load sensor.

[0002]

2. Description of the Related Art The prior art is shown in FIGS. The forklift shown in the figure is of a type called an unmanned low lift, and is equipped with a limit switch 02 for detecting the presence or absence of a load.

That is, the forklift is provided with a horizontal fork 01 which can be raised and lowered, a limit switch 02 is mounted on the side surface thereof, and a load detection lever 03 is attached to the limit switch 02.

The load detection lever 03 has a base end portion 03a,
The intermediate portion 03b and the tip portion 03c are bent and connected in order. Here, the base end 03a is the limit switch 0
2, the intermediate portion 03b has a shape that extends horizontally at a certain height from the upper surface of the fork 01, and the tip portion 03c has a shape that extends diagonally downward. have.

Therefore, when a load (not shown) is loaded on the fork 01, the load detection lever 03 is pushed downward, the limit switch 02 is turned on, and the presence of the load is detected. Further, a switch cover 04 covering the limit switch 02 is attached to a side surface of the fork 01, and a window portion through which the load detection lever 03 projects is formed on an upper surface of the switch cover 04.

In such a forklift, when the pallet 05 which is the work is to be lifted by the fork 01, the procedure shown in FIGS. 5 to 7 is performed. First, as shown in FIG. 5, with the fork 01 lowered,
The vehicle runs in the direction indicated by the arrow in the figure. Next, as shown in FIG. 6, the fork 01 is inserted into the pallet 05, and the fork 01 is raised as indicated by the arrow in the figure.

Then, as shown in FIG.
When the load detection lever 03 comes into contact with and is pushed down, the limit switch 02 is activated and turned on, and the presence or absence of a load is detected.

[0008]

However, in the above-mentioned conventional technique, since the limit switch 02 is attached to the side of the fork 01, the fork height and the fork width are large.

That is, the effective fork height is the fork 01.
Is added to the height of the fork 01 to the intermediate portion 03b of the load detection lever 03, and the effective fork length is the fork 01.
To the required switch width which is the width of the switch cover 04.

In particular, in order to operate the limit switch 02, a sufficient switch operating distance is required.
The effective fork height is increased, and therefore, it cannot be inserted unless it is a high pallet. FIG.
As shown in FIG. 3, when a lateral force is applied to the load detection lever 03, the load detection lever 03 may be bent.

[0011]

A forklift load sensor of the present invention which solves the above problems is a forklift having a horizontal fork that can be raised and lowered. A coil spring is stretched over the upper surface of the coil spring, and a thin plate switch for detecting the presence or absence of a load is inserted between the mounting bracket and the coil spring, and the upper surface of the coil spring is the upper surface of the fork. It is characterized in that it protrudes above. Here, the coil spring is characterized in that it has a function of being bent by a load and absorbing an impact.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a tensile coil spring receives a direct external force, and the elasticity thereof causes the thin plate switch to operate. Therefore, it is difficult to apply an impact force to the thin plate switch, and it is possible to avoid damage to the thin plate switch. Further, since the thin plate switch detects the presence or absence of a load, the switch operation distance is relatively small, and there is an advantage that it contributes to space saving and the like.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments shown in the drawings. One embodiment of the present invention is shown in FIGS. As shown in both figures, a mounting bracket 2 is mounted on the side surface of the fork 1 with a bracket fixing screw 7, and a coil spring 3 is provided on the upper surface of the mounting bracket 2 at both ends thereof with a spring fixing screw 4. It is stretched and attached by being fastened with.

A tape switch 5 is inserted between the coil spring 3 and the fork 1. The tape switch 5 has a thin plate shape and can detect the presence or absence of a load.

Also, with the tape switch 5 inserted, the upper surface of the coil spring 3 is in a state of projecting a certain distance above the upper surface of the fork 1. Therefore, when a load is loaded on the fork 1, the load of the load is transmitted to the tape switch 5 via the coil spring 3 and the tape switch 5 is turned on, whereby the presence or absence of the load is detected.

Further, since the coil spring 5 has an appropriate elasticity, it can be bent by a load and absorb a shock, so that no direct shock force is applied to the tape switch 5. Therefore, no matter which direction the shock is applied to the coil spring 5, it acts only indirectly on the tape switch 5, so that there is an advantage that the tape switch 5 operates reliably without breaking.

On the other hand, on the side surface of the fork 1, a mounting cover 2, a coil spring 3 and a protective cover 6 covering the tape switch 5 are mounted, and a window through which the upper surface of the coil spring 3 projects is attached to the protective cover 6. Parts are formed. Such an in-vehicle sensor of this embodiment is characterized in that the fork height and the fork width do not increase so much because the basic components such as the mounting bracket 2, the coil spring 3 and the tape switch 5 are small.

That is, the effective fork height is the height of the fork 1 plus the switch operating distance, which is the height from the upper surface of the fork 1 to the upper surface of the coil screw 3, and the effective fork length is It is the width of the fork 1 plus the required switch width, which is the width of the protective cover 6.

The structure of the tape switch 5 also has the advantage that the switch operating distance can be small. Therefore, it is possible to create an on-board sensor that is equivalent to or more than the limit switch system with space saving and low cost.

[0020]

As described above in detail with reference to the embodiments, in the present invention, the external force is directly applied by the tension coil spring, and the elasticity causes the thin plate switch to operate. It is difficult to apply an impact force to the switch, and it is possible to avoid damage to the thin plate switch. Further, since the thin plate switch detects the presence or absence of a load, the switch operation distance is relatively small, and there is an advantage that it contributes to space saving and the like.

[Brief description of the drawings]

FIG. 1 is a side view of a forklift presence sensor according to an embodiment of the present invention.

FIG. 2 is a plan view of a forklift presence sensor according to an embodiment of the present invention.

FIG. 3 is a side view of a conventional forklift load sensor.

FIG. 4 is a plan view of a conventional forklift load sensor.

FIG. 5 is an operation explanatory diagram of a forklift presence sensor.

FIG. 6 is an operation explanatory diagram of a forklift load sensor.

FIG. 7 is an operation explanatory diagram of a forklift presence sensor.

[Explanation of symbols]

 1 Fork 2 Mounting bracket 3 Coil spring 4 Spring fixing screw 5 Tape switch 6 Protective cover 7 Bracket fixing screw

Claims (2)

[Claims] 1. A forklift having a horizontal fork that can be lifted and lowered, wherein a mounting metal fitting is mounted on a side surface of the fork, and a coil spring is stretched over the upper surface of the mounting metal fitting. A forklift presence sensor, wherein a thin plate switch for detecting the presence / absence of a load is inserted between the coil spring and the coil spring, and the upper surface of the coil spring projects above the upper surface of the fork. 2. The forklift load sensor according to claim 1, wherein the coil spring has a function of being bent by a load to absorb an impact.