JPH08301598A - Unmanned low lift truck - Google Patents

Abstract

PURPOSE: To put limit switches for detecting a pallet and overwork, together in one place. CONSTITUTION: A rotating shaft 17 is rotatably provided at a fork base 4a elevated along with a pair of forks 5, and a spring lever rotated by a pallet 8 is fixed to the lower part of the rotating shaft 17. A torsion spring 10 is provided to energize the spring lever 9 toward the pallet 8, and a stopper pin 11 is provided to stop the rotation of the spring lever 9 in a reference position A. A first and a second limit switches 13, 14 are provided to detect the rotation of the spring lever 9 into positions B, C.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an unmanned low lift,
This is an improved detection means for detecting the presence of pallets.

[0002]

2. Description of the Related Art A forklift is used to carry a work on a pallet. The forklift is designed to put a pair of forks inside or below the pallet and then lift the forks to carry the work in that state.

As one of forklifts, there is an unmanned low lift that operates unmanned. The structure of the unmanned low lift is shown in FIG. In the figure, 1 is a main body, 2 is a drive steered wheel, 3 is a driven wheel, 4 is a lift table that is driven to move up and down, and 5 is a pair of forks integrated with the lift table 4.

As shown in FIG. 5, such an unmanned low lift is provided with a pallet detection switch 6 for recognizing the presence or absence of a pallet and an overtravel switch 7 for detecting an excessive insertion of a fork below the pallet. The pallet detection switch 6 is provided inside one of the forks 5, and when the pallet 8 causes the spring lever 6a to fall down as shown by an imaginary line, the cam 6b integral with the spring lever 6a rotates and the limit switch 6c moves. It is designed to detect this. On the other hand, the overtravel switch 7 is provided between the pair of forks 5, and when the lower portion of the rotatable push plate 7a is pushed to the left by the pallet 8, the shaft 7c resists the biasing force of the spring 7b. Is pushed to the left,
The limit switch 7e detects this by the movement of the cam 7d.

Due to the above structure, the pallet 8
When the fork 5 is inserted below, the spring lever 6a is pushed by the pallet 8. Then, the fork 5 is raised by the signal from the limit switch 6c. At this time, if the fork 5 is inserted too much and the pallet 8 pushes the push plate 7a, the limit switch 7e operates and the unmanned low lift is stopped urgently.

[0006]

However, since the pallet detection switch and the overtravel switch are separately installed, the unmanned low lift is expensive and requires a lot of space. Further, in order to protect the pallet detection switch, the thickness of the fork must be equal to or higher than the height of the limit switch, and the fork becomes thick. Further, the overtravel switch is weak against the external force F from the lateral direction and is easily damaged.

Therefore, an object of the present invention is to provide an unmanned low lift that solves the above problems.

[0008]

The structure of the present invention for achieving the above object is to provide a long vertical movement in an unmanned low lift in which a pair of forks extending in the horizontal direction are fixed to a vertically movable lift base. The shaft is rotatably provided between a pair of forks on the lifting table, and the base end of a spring lever, which is substantially perpendicular to the rotary shaft, is fixed to the rotary shaft at a position approximately the same height as the pallet on the fork. An urging means for pressing the spring lever toward the pallet in a rotation range in which the lever can be rotated by being pushed by the pallet, and a stopper for stopping the rotation of the spring lever at a reference position closest to the pallet in the rotation range. A first limit switch for detecting that the spring lever has been rotated slightly from the reference position by the pallet and a second limiter for detecting excessive rotation. And G Switch provided, first, the second limit switch primarily characterized in that the formation of the second notch portion to each other at a distant position in the axial direction of the rotating shaft to be engaged.

[0009]

[Operation] When a pair of forks is inserted under the pallet,
The pallet pushes the spring lever, and the rotating shaft rotates. As a result, only the first limit switch is turned on, the presence of the pallet is detected, and the pair of forks rises. If the pair of fork levers are inserted too much, the pallet pushes the spring levers more and the pivot shaft pivots more, turning on not only the first limit switch but also the second limit switch.
In this case, the unmanned low lift will be emergency stopped.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings.

The construction of the unmanned low lift according to the present invention is shown in FIG. FIG. 1A is a plan view of the main part, and FIG. 1B is a front view of the main part. In FIG. 1, reference numeral 4a denotes a fork base attached to an elevator (not shown), and 5 denotes a fork attached to the fork base 4a. Between the pair of forks 5 in the fork base 4a, a vertically long rotating shaft 17 is rotatably provided via a pair of bearings 18 and a frame 19. This rotation axis 1
At the lower end of 7 and its vicinity, there is a substantially U-shaped rotary shaft 1
Both ends of a spring lever 9 perpendicular to 7 are fixed. Here, 9a is a spring portion in which a wire is spirally wound.

In FIG. 1A, when the fork 5 is inserted toward the pallet 8 from the top to the bottom in the drawing, the spring lever 9 which is pushed by the pallet 8 and rotates in the direction of the arrow can be rotated. A torsion spring 10 is provided as a biasing means for biasing the spring lever 9 clockwise in FIG. 1A within the rotation range. The stopper pin 11 for stopping the rotation of the spring lever 9 at the reference position A against the clockwise urging of the spring lever 9 by the torsion spring 10 has a rotation shaft 17 as shown in FIG. While it is provided to penetrate the upper part of at a right angle,
The bracket 12 for receiving the stopper pin 11 is the frame 19
It is fixedly installed in.

The first limit switch 13 for detecting the presence of the pallet 8 on the fork 5 and detecting the presence of the pallet 8 on the fork 5, and the position of C. A second limit switch 14 is provided for detecting the state of overtravel by detecting that it has been pushed in. As shown in FIG. 2, the first limit switch 13 engages with a substantially conical cutout portion 15 formed on the rotary shaft 17, and the second limit switch 14 engages with an arcuate cutout portion 16. The notches 15 and 16 are formed as described above because the rotatable contact portions 13a and 14b of the first and second limit switches 13 and 14 rotate the rotating shaft 17 slightly or rotate a lot. This is because it is set so as to roll up to the outer surface of the rotating shaft 17 according to the movement.

Next, the operation of such an unmanned low lift will be described. When the fork 5 is inserted into the pallet 8 as shown in FIG. 1A and the pallet 8 rotates the spring lever 9 from the reference position A to the B position, as shown in FIG. , The contact portions 13a and 14a of the second limit switches 13 and 14 are initially in the notches 15 and 16, but
As shown in FIG. 3B, only the contact portion 13a has the cutout portion 1a.
5 rolls up on the outer peripheral surface of the rotating shaft 17, and only the first limit switch 13 is turned on. As a result, the presence of the pallet 8 on the pair of forks 5 is detected, and the forks 5 start rising.

If the fork 5 is inserted too much into the pallet 8, the spring lever 9 rotates to the position C in FIG. 1 (a). Then, as shown in FIG. 3C, not only the contact portion 13a but also the contact portion 14a rolls up on the outer peripheral surface of the rotating shaft 17, so that not only the first limit switch 13 but also the second limit switch 14 is turned on. Become. In this case, the unmanned low lift will be stopped in an emergency as in the past.

[0016]

As can be seen from the above description, according to the unmanned low lift of the present invention, the first limit switch for detecting the presence of the pallet and the second limit switch for detecting the overtravel are formed by a single rotary shaft. Since it is configured to operate, the occupied space can be smaller than the conventional one, and the cost is lower than the conventional one. Further, since the fork itself is not provided with the detecting means as in the conventional case, the thickness of the fork can be made thinner than in the conventional case. Further, when an external force is applied to the spring lever from the side, the spring absorbs the external force, so that damage is prevented.

[Brief description of drawings]

FIG. 1 is a perspective view of an essential part of an unmanned low lift according to the present invention.
(A) is a plan view and (b) is a front view.

FIG. 2 is a front view, (a) is a front view, (b) is a view taken along the line AA of (a), and (c) is a line taken along the line BB of (a). View.

FIG. 3 is an explanatory view of the operation of an unmanned low lift according to the present invention.

FIG. 4 relates to a conventional unmanned low lift, (a) is a plan view, (b) is a left side view, and (c) is a front view.

FIG. 5 is a plan view and a front view of a main part of a conventional unmanned low lift.

[Explanation of symbols]

 4a ... Fork base 5 ... Fork 8 ... Pallet 9 ... Spring lever 10 ... Torsion spring 11 ... Stopper pin 13 ... First limit switch 14 ... Second limit switch 15, 16 ... Notch portion 17 ... Rotating shaft

Claims (1)

[Claims] 1. In an unmanned low lift in which a pair of horizontally extending forks are fixed to an elevating table that can be moved up and down, a vertically long rotating shaft is rotatably provided between the pair of forks in the elevating table and rotates. The base end of the spring lever, which is substantially perpendicular to the rotation shaft, is fixed to the shaft at a position approximately the same height as the pallet on the fork, and the spring lever is pushed in the rotation range where it can be rotated by being pushed by the pallet. An urging means for pressing toward the pallet and a stopper for stopping the rotation of the spring lever at the reference position closest to the pallet in the rotation range are provided, and the spring lever is rotated slightly from the reference position by the pallet. Provided with a first limit switch for detecting that and a second limit switch for detecting excessive rotation,
An unmanned low lift characterized in that first and second cutout portions with which the first and second limit switches engage are formed at positions separated from each other in the axial direction of the rotating shaft.