JP2716877B2 - Forklift control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a forklift, and is particularly useful when applied to loading and unloading of a load placed on a pallet.

[0002]

2. Description of the Related Art A forklift is an industrial vehicle for cargo handling in which a mast for raising and lowering loaded luggage is provided in front of a vehicle body so as to be able to move between locations.

FIG. 3 is an explanatory view conceptually showing a front portion of a forklift, that is, an ascending and descending portion. As shown in the figure, the lift cylinder 1 is fixed to the outer mast 2, and the inner mast 3 is moved up and down using the outer mast 2 as a guide as the piston rod 1a expands and contracts. At this time, the outer mast 2 is fixed to a vehicle body (not shown).

On the other hand, a fork 4 for directly loading a load is
Its base end is fixed to the bracket 5 and protrudes forward, and is suspended on the chain 6 integrally with the bracket 5. The chain 6 is suspended from a chain wheel 7 rotatably supported on the inner mast 3, and has one end fixed to the bracket 5 and the other end fixed to the outer mast 2.

Thus, the fork 4 and the bracket 5, which are the elevating portions, not only rise with the rise of the inner mast 3, but also rise with the chain wheel 7 with respect to the fixing portion (outer mast 2). Relative to the position rises. In other words, the amount of rise of the elevating part with respect to the ground surface is determined by the amount of rise of the inner mast 3 and the length of the inner mast 3
It is a value obtained by adding the relative increase to.

[0006] With respect to the descent of the elevating unit, the same relationship as that at the time of ascent is established, except that the moving direction is reversed.

[0007] In the cargo handling using the forklift, as shown in FIG. 4, generally, the luggage (not shown) is moved up and down and transported with the luggage (not shown) placed on the pallet 30. The pallet 30 is configured such that an upper plate 30a made of a flat plate and a lower plate 30b similar to the lower plate 30b are opposed to each other via a space 30c. It can be inserted.

In the above-mentioned cargo handling, when unloading the cargo, the fork 4 is lowered until the lower plate 30b of the pallet 30 comes into contact with a predetermined unloading place such as the ground surface, and then the vehicle body is retracted, and the fork 4 is moved down. It is moved in the horizontal direction and pulled out of the space 30c.

[0009]

As described above, when the fork 4 is pulled out of the space 30c of the pallet 30, there is no problem if the fork 4 is floating in the space 30c as shown in FIG. However, the lowering of the fork 4 is not sufficient, and as shown in FIG.
In the case where the fork 4 is pulled out, the pallet 30 may be dragged when the fork 4 is pulled out, which may hinder the predetermined unloading operation. Incidentally, the state as shown in FIG. 4 is likely to occur when unloading a shelf, not a floor, but a shelf provided at a high position which is a blind spot of an operator's line of sight.

Further, when the fork 4 is lowered too much and the chain 6 is in a loosened state as shown in FIG.
When the fork 4 is pulled out in this state, the pallet 30 may be damaged by dragging the pallet 30 with the fork 4.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and has as its object to provide a forklift control device capable of displaying this state when there is no load so that the fork can be pulled out of the pallet satisfactorily. And

[0012]

The structure of the present invention for achieving the above object is as follows.

The present invention relates to a forklift control device which raises and lowers a bracket suspended on a chain as a piston rod of a lift cylinder expands and contracts, and raises and lowers a load loaded on a fork having a base end fixed to the bracket. A load detecting means for detecting the load of the load acting on the lift cylinder, an unloaded load detected by the load detecting means when the load is empty and stored in advance, and a load detected by the load detecting means in real time. It is characterized in that it comprises a controller for sending out a no-load signal when the two values are equal, and a display means for displaying the no-load state when the no-load signal is input.

[0014]

According to the present invention having the above-described structure, the fact that the load acting on the fork is the unloaded weight is displayed on the display means. Therefore, in a state where the no-load state is displayed on the display means, a good unloading operation can be performed by pulling out the fork from the pallet.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments. The same members as those in FIGS. 3 to 6 are denoted by the same reference numerals.

FIG. 2 is a perspective view showing an example of a forklift to which the embodiment of the present invention is applied. As shown in the figure,
The lift cylinder 1 is fixed to a pair of left and right outer masts 2, and lifts and lowers a pair of left and right inner masts 3 using the outer mast 2 as a guide as the piston rod 1 a expands and contracts. At this time, outer mast 2
Is fixed to the vehicle body 7 in front of the vehicle body 7. As a result, the chain 6 (FIG.
(See FIG. 6 to FIG. 6).

The tilt cylinder 8, together with the outer mast 2 and the inner mast 3, moves the elevating portion forward (to the opposite side of the vehicle body 7).
Side) and rearward (toward the vehicle body 7). That is, in the case of unloading, it tilts forward, and in the case of unloading and transporting luggage, it tilts rearward, so that the respective workability is maintained well and safety is ensured.

The work machine levers 9a and 9b are used to control the operation of the lift cylinder 1 and the tilt cylinder 8 via the controller 10 and the electromagnetic proportional control valve 11 when operated by an operator, and perform an emergency stop. Is stored in the joystick box 13 together with the safety switch 12. Work implement levers 9c, 9d, 9
"e" is for dealing with a case where various attachments such as a roll clamp and a bale clamp are attached. The seat switch 14 operates when an operator sits on the driver's seat 15 and outputs an output signal to the controller 10.

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, the same parts as those in FIG. 2 are denoted by the same reference numerals, and duplicate description will be omitted.

As shown in FIG. 1, the working machine lever 9a is
A lever operation signal S ₁ , which is formed by a potentiometer and whose current value is proportional to the operation amount, is sent to the controller 10. The controller 10 sends the flow control signal S ₂ to adjust the degree of opening of the spool of the electromagnetic proportional control valve 11 on the basis of the lever operation signal S _1. By the electromagnetic proportional control valve 11 to its spool in proportion to the magnitude of the flow control signal S ₂ to the mobile work machine lever operation speed of the lift cylinder 1 to control the flow rate of the hydraulic fluid flowing through the hydraulic line 16 9a, 9b
Is controlled so as to correspond to the operation amount.

The hydraulic pressure sensor 17 is disposed in the hydraulic line 16 and sends out a hydraulic pressure signal S ₃ indicating the pressure of the hydraulic pressure in the hydraulic line 16. The controller 10 processes the hydraulic signal S ₃ to calculate the load applied to the lift cylinder 1. That is, in the present embodiment, the hydraulic pressure sensor 17 serves as load detecting means for detecting the load of the load acting on the lift cylinder 1.

The storage switch 18 is for reading and storing the hydraulic signal S ₃ sent by the hydraulic sensor 17 at the time when the switch is turned on to the controller 10.
Therefore, if the storage switch 18 is turned on in a no-load state, a no-load (a load based on the fork 4 and the bracket 5 forming the elevating portion) can be stored in the controller 10. In this embodiment, when no load is applied, the controller is turned on to the storage switch 18 so that the controller 10 stores the no-load load in advance. Thus, the controller 10 compares the unloaded load stored in advance and load calculated on the basis of the oil pressure signal S ₃ which is detected in real time, both values sends a no-load signal S ₄ when equal.

The display unit 19 is, for example, Yes is formed by the lamp and arranged on the console box 20 in the vicinity of the driver's seat 15, (lit when the lamp) operated by a no-load signal S ₄ to the driver's seat 15 The operator is notified of the no-load condition.

The controller 10 further includes a warning light 21
When the starter switch 22 housed in the console box 20 is turned on, power is supplied from the battery 23 to operate, and when the safety switch 12 is operated and the seat switch 14 is not operated, the current of the flow control signal S ₂ is Current proportional control valve 1 with a value of zero
Control is performed so that the opening degree of 1 becomes zero.

In the figure, reference numeral 24 denotes a hydraulic pump, and reference numeral 25 denotes a hydraulic oil source. Also, the electromagnetic proportional control valve 11, the hydraulic line 1
6. Hydraulic components such as the oil pressure sensor 17
The numbers corresponding to the numbers a and 9e are provided.

In the above embodiment, the no-load is calculated based on the hydraulic signal S ₃ read into the controller 10 by turning on the storage switch 18 in the no-load state of the forklift, and this value is stored in the controller 10. I have.

On the other hand, the controller 10 compares real-time and the applied load was calculated based on the hydraulic signal S ₃ which is detected in real time, and the no-load weight, when both values are equal, sends a no-load signal S ₄ Then, the display unit 19 is driven.

As shown in FIG. 5, when the fork 4 is located in the space 30c of the pallet 30 and the fork 4 can be pulled out from the pallet 30, the load detected in real time is no load. Therefore, the operator may proceed with the work by visually recognizing the display on the display unit 19 driven when the state shown in FIG. 5 is obtained.

[0029]

As described in detail with the above embodiment, according to the present invention, the no-load state of the forklift can be confirmed by the display means. Can be satisfactorily performed without damaging the pallet or the like.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a perspective view showing a forklift to which the embodiment of the present invention is applied.

FIG. 3 is an explanatory view conceptually showing a lifting part of a forklift.

FIG. 4 is an explanatory diagram conceptually showing a state in which a pallet is supported by a fork of a forklift (a state in which inconvenience occurs when the fork is pulled out of the pallet).

FIG. 5 is an explanatory diagram conceptually showing a state in which a fork of a forklift can be favorably pulled out from a pallet.

FIG. 6 is an explanatory view conceptually showing a state in which the pallet may be damaged when the fork of the forklift is pulled out from the pallet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lift cylinder 1a Piston rod 4 Fork 5 Bracket 6 Chain 10 Controller 17 Oil pressure sensor 19 Display

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshiyuki Midorikawa 3000 Tana, Sagamihara-shi, Kanagawa M.H.A. Showa 61-72594 (JP, U) Actually open Hei 1-1147394 (JP, U)

Claims (1)

(57) [Claims] 1. A forklift control device which raises and lowers a bracket suspended on a chain as the piston rod of a lift cylinder expands and contracts, and raises and lowers a load loaded on a fork having a base end fixed to the bracket. A load detecting means for detecting the load of the load acting on the lift cylinder, a no-load detected by the load detecting means when the load is empty and stored in advance, and a load detected by the load detecting means in real time. A controller for sending a no-load signal when the two values are equal to each other, and a display means for displaying that there is no load when the no-load signal is input. apparatus.