JP2002059846A - Lift truck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To safely travel forward and backward at a desired speed. SOLUTION: In a lift truck having an operation arm 13 extending backward from a self traveling truck main body 3 arranging a lift 7 on a front part thereof and changing a traveling direction of the truck main body 3 by a swing of the operation arm 13 in left or right, handles 14A, 14B are pivotally attached to a tip part of the operation arm 13 through a pivot shaft with allowing pivotal movement within a fixed range in a forward and a backward directions, and a potentiometer 17 detecting a rotation of the handle parts 14A, 148 is provided. The truck main body 3 is traveled forward (a) or backward (b) according to a detected signal from the potentiometer 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lift truck capable of safely moving a low-lift type lift truck or the like forward and backward at a desired speed.

[0002]

2. Description of the Related Art FIGS. 12 and 13 show an example of a conventional low-lift type lift truck. this is,
One drive wheel 1 and two caster wheels 2
And a motor 5 with an electromagnetic brake 5a for rotating the drive wheel 1 forward and reverse through a gear mechanism 4 so as to be rotatable around a vertical axis O. While being placed, the truck body 3
The start switch 6 is provided on the upper surface of the casing 3a.

A pair of left and right lifts 7 are provided at the front of the truck body 3 so as to be able to move up and down, and a load wheel 9 provided at the end of each lift 7 via a swing bracket 8 is grounded to the floor F. The piston rods of a pair of right and left hydraulic cylinders 10 provided in the truck body 3 are connected to a swing bracket 8 via a link mechanism 11.

Further, the casing 3a is
5b extending upward along the vertical axis O
The operation arm 13 is connected to the bearing portion 5b via a connection shaft 12 so as to be vertically movable within a predetermined angle α (about 90 °). The handle 1 is protruded, and the handle 1
By gripping and swinging the drive wheel 1 left and right, the drive wheel 1 can be rotated about the vertical axis O via the operation arm 13 and the electric motor 5, and the traveling direction of the truck body 3 can be freely changed.

[0005] A pair of left and right operation rings 15 rotatably fitted to the distal ends of the handles 14 are integrally connected to each other via a connection shaft 16.
A rotary potentiometer (detector) 17 built in 4 is connected to one operation ring 15, and the operation ring 15 is turned c or clockwise d from the neutral position N.
By doing so (see FIG. 15), the electric motor 5 is rotated forward or backward based on the detection signal of the potentiometer 17 for detecting this, and the truck body 3 is moved forward a or backward b at a desired speed. Reference numeral 18 denotes a lifting spring that urges the operation arm 13 upward. Reference numeral 19 denotes a slight angle β between the standing state of the operation arm 13 (see the phantom line in FIG. 12) and the horizontal state of the operation arm 13 (see the solid line in FIG. 12). Brake switches 20 to 22 for detecting the state of being pressed down (about 3 °) and activating the electromagnetic brake 5 a are a lift button for raising and lowering and an emergency stop button, and are provided on the distal end surface of the operation arm 13.

In the above configuration, when the load W is lifted up, the start switch 6 is turned on, and the operator M grasps one handle 14 and operates the operation arm 13.
Down to a substantially horizontal state (see the solid line in FIG. 12), and FIG.
As shown in FIG. 4 and FIG.
Of the truck body 3 at a desired speed by turning the operation ring 15 counterclockwise from the neutral position N, and moving the lift 7 under the load W, The user may press the lift button 20. Thus, by causing the hydraulic cylinder 10 to extend and drive, the swing bracket 8 is erected via the link mechanism 11, and the lift 7 can be lifted to lift the load W (see the phantom line in FIG. 12).

[0007] When transporting the load W to a predetermined position,
By turning the operation ring 15 counterclockwise from the neutral position N in the same procedure as described above, the truck body 3 is advanced a at a desired speed, or by turning the operation ring 15 clockwise from the neutral position N, What is necessary is just to move the truck body 3 backward at a desired speed.

In order to lift down the luggage W, the lowering lift button 21 may be pressed. As a result, the hydraulic cylinder 10 is driven to contract, whereby the link mechanism 11
The swing bracket 8 is tilted down through this, and the lift 7 can be lowered to drop the load W (see the solid line in FIG. 12).

[0009]

In the above-mentioned conventional configuration,
For example, when the truck body 3 is moved backward b, the operation ring 1 is operated by the thumb Ma with the operator M facing backward.
5 (see FIGS. 14 and 15), and it is necessary to operate the operation ring 15 in an unreasonable posture and in a state where it cannot be seen.
It is difficult to operate the truck body 5 smoothly.
Is too slow or too fast, and it is difficult to keep the running speed of the truck body 3 appropriate. In particular, when the running speed is too fast, the truck body 3 may come into contact with the operator M. Yes, there is a problem with safety.

An object of the present invention is to provide a lift truck capable of safely moving back and forth at a desired speed in view of the above-mentioned conventional drawbacks.

[0011]

In order to achieve the above object, according to the first aspect of the present invention, an operation arm extends rearward from a self-propelled truck body having a lift disposed at a front portion thereof. In a lift truck in which the traveling direction of the truck body is changed by swinging the arm left and right, a handle is pivotally attached to a front end portion of the operation arm via a pivot shaft so as to be rotatable within a predetermined range in the front and rear direction. Along with
A detector for detecting the rotation of the handle is provided,
The truck body is moved forward or backward based on a detection signal of the detector.

According to the above construction, by gripping and pushing and pulling the handle provided at the distal end of the operating arm, the handle is rotated forward or backward, and the rotation is detected by a detector. The truck body can be moved forward or backward at a speed proportional to the turning angle of the steering wheel based on the signal. In this case, the direction of forward and backward movement of the truck body and the pushing / pulling direction of the steering wheel coincide with each other. It is possible to smoothly move the truck body back and forth at a desired speed in an easy operation posture. Therefore, for example, even when the operator moves the truck body backward while facing backward, the truck body can be safely driven so as not to contact the operator.

According to a second aspect of the present invention, in the first aspect of the present invention, a biasing means for holding the handle at a neutral position within a rotation range of the handle is provided between the handle and the operation arm. It is characterized by being interposed in.

According to the above configuration, after the handle is turned forward or backward, the handle can be automatically returned to the neutral position by the urging means only by releasing the push / pull of the handle.

The third aspect of the present invention provides the first or second aspect.
In the invention described above, a pair of left and right handles are provided, and gears provided at base ends of the two handles are meshed with each other.

According to the above configuration, since both handles are interlocked with each other via the gears, both handles can be simultaneously and integrally rotated only by pushing or pulling one of the handles. Therefore, the rotation of both handles can be detected by one detector, and the structure is simpler and the manufacturing cost can be reduced as compared with the case where the detectors are provided on both the handles.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the detecting rod of the detector is integrally connected to the handle concentrically with the pivot shaft. It is characterized by.

According to the above configuration, the detection rod of the detector is integrally connected to the handle concentrically with the pivot shaft.
By simply turning the handle about the pivot axis, the turning direction and the turning angle of the handle can be accurately detected by the detector.

According to a fifth aspect of the present invention, there is provided the cam according to any one of the first to third aspects, wherein a cam roller rotatably provided on a detection rod of the detector is integrally formed at a base end portion of the handle. The detection rod is extended and retracted via a cam and a cam roller in conjunction with the rotation of the handle.

According to the above arrangement, the turning direction and the turning angle of the handle can be accurately detected by the detector via the cam and the cam roller integrally formed at the base end of the handle.

According to a sixth aspect of the present invention, in the first aspect of the present invention, the detector is a potentiometer.

According to the above configuration, the turning direction and the turning angle of the handle can be accurately detected by the potentiometer, and the truck body can be moved forward or backward as desired based on the detection signal.

[0023]

1 and 2 show a low-lift type lift truck according to a first embodiment of the present invention, in which an operation arm 13 is rotatable about a connection shaft 12. FIG. It has a base frame 13a, and a casing 13b having a substantially T-shape in a plan view and externally fitted to the distal end of the base frame 13a, and a pair of left and right handles 14A, 14A, A rotary potentiometer (detector) 17 for detecting rotation of the handles 14A, 14B is provided, as well as being rotatable in the front-rear direction. Since the configuration other than the above is substantially the same as the configuration shown in FIGS. 12 and 13, the same portions are denoted by the same reference numerals and description thereof is omitted.

As shown in FIGS. 3 to 7, the gear mechanism 25 includes a pair of left and right circular plates rotatably pivoted via a pivot shaft 27 to a base plate 26 fixed to the distal end of a base frame 13a. Gears 28a formed on the outer peripheral edges of the disk portions 28A and 28B are meshed with each other, and the detection rod 17a of the rotary potentiometer 17 fixed to the base plate 26 via a connecting member 29 is provided. A boss 28b protruding from the upper surface of one disk portion 28A concentrically with the pivot 27 is connected, and the base end of each handle 14A, 14B passes through the opening of the casing 13b. 28B, and the rotation range r of each of the handles 14A, 14B.
The pair of front and rear stopper pins 30 for regulating the base plate 2
6 protrudes.

According to the above configuration, the two handles 14A, 1
Since the wheels 4B are interlocked with each other via the gear 28a, the two handles 14A and 14B can be simultaneously and integrally rotated only by pushing or pulling one of the handles 14A (or 14B). Therefore, the rotation of both handles 14A and 14B can be detected by one potentiometer 17, and compared with the case where the potentiometers 17 are provided on both handles 14A and 14B, respectively.
The structure is simple and the production cost can be reduced. Further, since the detecting rod 17a of the potentiometer 17 is connected to the center of the disk portion 28A, the turning direction and the turning angle of each handle 14A, 14B can be accurately detected by the potentiometer 17.

As shown in FIG. 5 and FIG.
An engagement pin 31 is vertically provided on the outer peripheral portion of the lower surface of each of the base plates 26A and 28B. A coil spring (biasing means) 33 is externally fitted to a boss 26a provided to rotatably support each pivot shaft 27, and both ends 33a, 3 of each coil spring 33 crossing in an X-shape.
The engaging pin 31 and the fixing pin 32 are sandwiched by 3b, and by turning the handles 14A and 14B forward e or backward f (see FIGS. 8B and 8C), the engaging pin 31 is moved. The engagement pin 31 is returned to the original position by the urging force of the coil spring 33 by releasing the pushing and pulling of the handles 14A and 14B, being separated from the fixing pin 32 against the coil spring 33, and 14A, 14
B can be automatically returned to the neutral position N (see FIG. 5).

The operation of the forward / backward movement a, b of the truck body 3 based on the above configuration will be described. The handles 14A, 14B
8A, when the push-pull operation is not performed, as shown in FIG.
B is held in the neutral position N and the potentiometer 1
7 is also set to the neutral position N, and the truck body 3 is stopped.

When the truck body 3 is to be advanced a from the above state, the operator M has only to grip one handle 14A (or 14B) and push it forward e. Thereby, as shown in FIG. 8B, each handle 14A, 1
The detection rod 17a is turned clockwise in conjunction with the forward rotation of the 4B, and the motor 5 is driven at a predetermined speed based on the detection signal output from the potentiometer 17 in proportion to the rotation angle H1 of each of the handles 14A, 14B. And the truck body 3
At a desired speed.

When the truck body 3 is to be moved backward b, the operator M operates one of the handles 14A (or 1).
4B) may be grasped and pulled backward f. by this,
As shown in FIG. 8C, the detection rod 17a is turned counterclockwise in conjunction with the rotation of the handles 14A, 14B backward f.
The motor 5 is reversed at a predetermined speed based on the detection signal output from the potentiometer 17 in proportion to the rotation angle H2 of each of the handles 14A, 14B, and the truck body 3 can be moved backward b at a desired speed.

According to the above configuration, by gripping and pushing and pulling the handles 14A, 14B provided at the distal end of the operation arm 13, the handles 14A, 14B are rotated forward e or backward f, and the rotation is performed. Based on the detection signal from the potentiometer 17 for detecting the movement, the track body 3 can be moved forward or backward b at a speed proportional to the rotation angles H1 and H2 of the handles 14A and 14B. Forward and backward a and b directions and handle 1
Since the push-pull directions e and f of 4A and 14B coincide with each other, the operator M can smoothly move the truck body 3 forward and backward a and b at a desired speed in an easy operation posture. Therefore, for example, even when the operator M moves the truck body 3 backward b while facing the rearward f, the truck body 3 can be safely driven so as not to contact the operator M (see FIG. 1).

FIGS. 9 to 11 show a low-lift type lift truck according to a second embodiment of the present invention, in which a ridge 34a and a valley are formed on the outer peripheral surface of one disk portion 28A (or 28B). A cam roller 35 rotatably attached to the detection rod 17a of the slide potentiometer 17 fixed to the base plate 26 is in contact with the cam 34. The configuration other than the above is substantially the same as that of the first embodiment shown in FIGS.

The function of the forward and backward movements a and b of the truck body 3 will be described based on the above configuration. The handles 14A and 14B
11A, the handles 14A and 14B are held at the neutral position N as shown in FIG. 11A.
The protruding length h of the detection rod 17a of the potentiometer 17 is set to an intermediate position by contacting the intermediate portion between the groove 4a and the valley portion 34b, and the truck body 3 is stopped.

In order to advance the truck body 3 from the above state, the operator M grasps one of the handles 14A (or 14B) and pushes it forward e.
As shown in (b), each of the handles 14A and 14B is rotated forward e from the neutral position N, and the cam roller 35 comes into contact with the crest 34a of the cam 34, thereby causing the detection rod 17a of the potentiometer 17 to rotate. The protrusion length h1 becomes shorter,
The electric motor 5 is normally rotated at a predetermined speed based on a detection signal output from the potentiometer 17 in proportion to the protruding length h1, and the truck body 3 can be advanced a at a desired speed. In other words, when pressed strongly, the rotation speed of the electric motor 5 increases and the truck moves forward, and when pressed weakly, the rotation speed of the electric motor 5 decreases and the truck moves forward slowly. Also, if the operator M stops, there is no pushing force, so the truck naturally slows down and stops.

In order to move the truck body 3 backward b, the operator M operates the handle 14A (or 14A).
B) is gripped and pulled rearward f, as shown in FIG.
As shown in (c), each of the handles 14A and 14B is rotated rearward from the neutral position N, and the cam roller 35 comes into contact with the valley 34b of the cam 34, so that the detection rod 17a of the potentiometer 17 is The protruding length h2 becomes longer,
The motor 5 is reversed at a predetermined speed based on the detection signal output from the potentiometer 17 in proportion to the protrusion length h2, and the truck body 3 can be moved backward b at a desired speed.

According to the above configuration, one disk portion 28A
(Or 28B) formed cam 34 and cam roller 3
5, each handle 14 by a potentiometer 17
The rotation direction and the rotation angle of A and 14B can be accurately detected.

In the first and second embodiments, the handle 1
Although the potentiometer 17 was used to detect the push and pull of the 4A and 14B, it is not limited to this.
Instead of the potentiometer 17, for example, various detection devices such as a load cell may be used.

[0037]

According to the first aspect of the present invention, by gripping and pushing and pulling the handle provided at the distal end of the operation arm, the handle is rotated forward or backward, and the rotation is detected. The truck body can be moved forward or backward at a speed proportional to the turning angle of the steering wheel based on the detection signal from the detector that performs the steering operation. Therefore, the operator can smoothly move the truck body back and forth at a desired speed in an easy operation posture. Therefore,
For example, even when the truck body moves backward while the operator faces backward, the truck body can be safely driven so as not to contact the operator.

According to the second aspect of the present invention, after the handle is turned forward or backward, the handle is automatically returned to the neutral position by the urging means only by releasing the push / pull of the handle. be able to.

According to the third aspect of the present invention, the two handles are interlocked with each other via the gear, so that only one of the handles is pushed and pulled to simultaneously rotate the two handles simultaneously. be able to. Therefore, the rotation of both handles can be detected by one detector, and the structure is simpler and the manufacturing cost can be reduced as compared with the case where the detectors are provided on both the handles.

According to the fourth aspect of the present invention, since the detection rod of the detector is integrally connected to the handle concentrically with the pivot shaft, the handle is simply rotated about the pivot shaft. Thus, the turning direction and the turning angle of the handle can be accurately detected by the detector.

According to the fifth aspect of the present invention, the turning direction and the turning angle of the handle can be accurately detected by the detector via the cam and the cam roller integrally formed at the base end of the handle.

According to the sixth aspect of the present invention, the turning direction and the turning angle of the handle can be accurately detected by the potentiometer, and the track body is advanced or backward as desired based on the detection signal. Can be.

[Brief description of the drawings]

FIG. 1 is a side view of a lift truck according to a first embodiment of the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a side view of the main part.

FIG. 4 is a plan view of the main part.

FIG. 5 is a horizontal sectional view of the main part.

6 is a view as viewed in the direction of arrows BB in FIG.

FIG. 7 is a view taken in the direction of the arrows CC in FIG. 5;

FIGS. 8A to 8C are explanatory diagrams showing the same detecting action.

FIG. 9 is a horizontal sectional view of a main part of a lift truck according to a second embodiment of the present invention.

FIG. 10 is a view taken in the direction of the arrow DD in FIG. 9;

FIGS. 11A to 11C are explanatory diagrams showing the same detecting operation.

FIG. 12 is a side view showing a conventional example.

FIG. 13 is a plan view of the same.

FIG. 14 is an enlarged plan view of the main part.

15 is a view as viewed in the direction of arrows AA in FIG. 14;

[Explanation of symbols]

 Reference Signs List 3 Truck body 7 Lift 13 Operation arm 14A, 14B Handle 17 Potentiometer (detector) 17a Potentiometer detection rod 27 Pivot shaft 28a Gear 33 Coil spring (biasing means) 34 Cam 35 Cam roller N Neutral position r Handle rotation range a Forward b Reverse

Claims (6)

[Claims] An operation arm extends rearward from a self-propelled truck body having a lift disposed at a front portion, and the traveling direction of the truck body is changed by swinging the operation arm left and right. In the truck, a handle is pivotally attached to a distal end portion of the operation arm via a pivot shaft so as to be rotatable in a predetermined range in the front-rear direction, and a detector for detecting rotation of the handle is provided, A lift truck, wherein the truck body is moved forward or backward based on a detection signal of the detector. 2. The device according to claim 1, wherein a biasing means for holding the handle at a neutral position within a rotation range of the handle is interposed between the handle and the operation arm. Lift truck. 3. The lift truck according to claim 1, wherein a pair of left and right handles are provided, and gears provided at base ends of the two handles are meshed with each other. 4. The lift truck according to claim 1, wherein a detection rod of the detector is integrally connected to a handle concentrically with the pivot shaft. 5. A cam roller rotatably provided on a detection rod of the detector is engaged with a cam integrally formed at a base end of the handle, and interlocks with the cam and the cam roller in conjunction with rotation of the handle. The lift truck according to any one of claims 1 to 3, wherein the detection rod is extended and retracted. 6. The lift truck according to claim 1, wherein the detector is a potentiometer.