JP2000318996A - Automatic height control device for fork lift - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cope with various load postures or load storage spaces by providing a height correcting means capable of changing a correction height stored in a target height setting means by the instruction of an operator. SOLUTION: When a desired step of a step selecting switch 25a is turned ON, and an instruction switch 25b is turned ON, the height H at that time is incorporated a target height setting means 25 and stored as an n-step load receiving height in the target height setting means 25. To set an independent correction height every step, an independent switch 27e is turned ON. When the independent switch 27e is turned ON, the step to be set by the step selection switch 25a of the target height setting means 25 is selected, and the independent correction height from the load receiving position is set by an increase switch 27b or a decrease switch 27c according to the respective step. When the instruction switch 25b of the target height setting means 25 is then turned ON, the target height setting means 25 takes in and stores the independent correction height.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic lift control device for a forklift.

[0002]

2. Description of the Related Art A forklift 40 shown in FIG. 6 drives a pair of left and right front wheels 41, 41 and a pair of left and right rear wheels 42, 41.
It is a four-wheeled vehicle that steers 42. An inner rail 12 is provided between a pair of left and right outer rails 11 erected at the front of a body frame 45 of a forklift so as to be able to move up and down. A finger board 51 having a fork 13 attached to the inner rail 12 is provided. Is mounted so as to be able to move up and down via a chain (not shown). The outer rail 11 is connected to the vehicle body frame 45 via a tilt cylinder 49. When an operator operates the tilt lever 49, the tilt cylinder 50 is driven to expand and contract, and the outer rail 11 is tilted. Outer rail 1
1 is connected to the upper end of the inner rail 12 so that when the operator operates the lift lever 22, the lift cylinder 14 is driven to expand and contract to move the fork 13 up and down. It has become.

In the forklift described above,
As one of the automation techniques for simplifying and facilitating the operation, there is an automatic lift control for automatically controlling the lift of the fork 13 to a target lift. As the target lift in the automatic lift control, the lift at the loading position and the lift at the loading position are set. The unloading position is a position where a fork is inserted into each of the fork insertion openings of a plurality of pallets placed on a plurality of racks. At each loading position, insert the fork into the fork slot and lift the pallet. The loading position is a position at which the operator starts manually placing the loaded pallet slowly and slowly on the rack. Before the work, the operator teaches and stores a plurality of unloading heights in the automatic lifting control device according to the heights of the racks in the plurality of stages. Further, the plurality of loading heights corresponding to the plurality of loading positions are set at positions higher than the taught plurality of loading heights by a correction height of the same height (for example, 200 mm).

[0004]

However, the above technique has the following problems. A uniform correction height is set at the time of forklift production and shipped. Since this correction height cannot be changed at the work site, when the distance between the top and bottom of the rack is not sufficient and the height of the load is high, the load may come into contact with the rack or the like, causing collapse or damage to the load. . That is, it is difficult for the automatic lift control based on the target lift set based on the uniform and constant correction height that cannot be changed at the work site to correspond to a variety of packing forms and loading places. There's a problem. In addition, during actual work, the height is manually adjusted before the pallet is stored in the rack and the load is reloaded so that the operator does not contact the load, so workability is not good. There's a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide an automatic lift control device for a forklift capable of responding to various types of loads and places of loading.

[0006]

In order to achieve the above object, a first aspect of the present invention provides a lift sensor for detecting a lift of a fork of a forklift and a lift cylinder for controlling the lift. The electromagnetic proportional valve to be operated, the plurality of unloading heights taught by the operator, and the height from each of the unloading heights to the corresponding loading position, the correction height of a fixed value uniformly stored in advance, and the operator When any of the plurality of loading positions is selected, the corresponding lifting height of the plurality of stored lifting heights is set to the target lifting height, and is stored when any of the plurality of loading positions is selected. A target lift setting means for setting a storage height obtained by adding a correction height stored in a corresponding loading height among a plurality of loading heights to a target height; and a set target height and a lift. Based on the deviation from the height detected by the height sensor And a controller for controlling the lift by outputting the calculated command signal to an electromagnetic proportional valve, and changing the correction height stored by the target lift setting means in accordance with the teaching of the operator. The apparatus is provided with a height correcting means that can be used.

According to the first invention, the height correction means teaches and stores the corrected height of the unloading height from the unloading height to the target height setting means before work. When the operator inputs the desired number of racks on the panel of the target lift setting means, for example, and selects a loading position as the target lift, the target lift setting means stores and stores the target lift corresponding to the selected number of steps. The value obtained by adding the unloading lift and the correction height is set as the target lift at the loading position. The set target lift is output to the controller. Then, for example, when the operator operates the lift lever in a direction in which the fork approaches the target lift,
The controller outputs a valve opening command value based on a deviation value between the target lift and the actual lift detected by the lift sensor to the proportional solenoid valve. Pressure oil is discharged from the proportional solenoid valve to the lift cylinder, and the fork reaches the target lift. As described above, since the operator teaches and stores the height of the load and the corrected height suitable for the loading place to the target height setting means before the work, an automatic lift control device for a forklift with good workability is obtained. be able to.

According to a second aspect based on the first aspect, the height correction means can set a correction height corresponding to each of a plurality of unloading lifts, and the target lift setting means comprises a plurality of operators. When any one of the loading positions is selected, the loading height obtained by adding the corresponding lifting height and the correction height is set to the target lifting height.

According to the second invention, the height correction means can teach and store the individual correction height from the unloading height of the unloading height to the target height setting means before the work. For example, the operator inputs the desired number of racks on the panel of the target lift setting means, and sets the loading position as the target lift,
If you select individual correction heights as the correction height,
The target lift setting means calculates a value obtained by adding the unloading height stored corresponding to the selected number of stages and the individual correction height individually stored corresponding to the selected number of stages. Set as high. The set target lift is output to the controller, and the fork reaches the target lift. in this way,
Before the work, the operator can set the individual correction height in consideration of the height of the load on the pallet and the spacing between racks, etc., and set the loading height for each number of racks. And an automatic lift control device of a forklift corresponding to a loading place.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a hardware configuration. FIG.
The same components as those described above are denoted by the same reference numerals and will be described. An outer rail 11 serving as a basis for a lifting device for the fork 13 and a lift cylinder 14 for lifting and lowering the fork 13 are attached to the front of the body of the forklift. The inner rail 12 to which the finger board 51 to which the fork 13 is attached is slidably attached is slidably attached to the outer rail 11. The chain 19 suspending the upper end of the finger board 51 is fixed to the upper part of the outer rail 11 via the pulley 15 provided on the upper part of the inner rail 12. Lift cylinder 14 for raising and lowering fork 13
One end of the rod 17 is connected to the upper end of the inner rail 12 via a support 18 projecting from the inner rail 12. The rod 1 is located between the bottom chamber of the lift cylinder 14 and the hydraulic pump 20 driven by the electric motor 21.
Hydraulic piping is provided through an electromagnetic proportional valve 16 for controlling expansion and contraction of the valve 7. The head chamber of the lift cylinder 14 communicates directly with the hydraulic tank 35 via a hydraulic pipe. A lift lever 22 that outputs a command to the electromagnetic proportional valve 16 is provided at an operator's seat (not shown).

As a detector, the distance between the outer rail 11 and the inner rail 12 is measured at the upper end of the outer rail 11, and the fork 1 is moved from the fork reference position of the body frame.
A lift sensor 23 that outputs a lift of No. 3 is attached.
The lift sensor 23 uses, for example, a reel-type encoder that measures a distance by the length of the wire 36 forming a reel, and one end of the wire 36 is fixed to the support 18. A lever operation amount detector 24 that detects the lever operation amount Lev is provided near the center of rotation of the lift lever 22.

A controller 26 for calculating a control command to be output to the electromagnetic proportional valve 16 and the electric motor 21 includes a target lift Ht from a target lift setting means 25 and a lift sensor 23.
And the lever operation amount Lev from the lever operation amount detector 24 are input via an input circuit (not shown). The controller 26 outputs to the electromagnetic proportional valve 16 a valve opening command value Sv corresponding to a lift deviation indicating a difference between the target lift Ht and the lift H. Also, the controller 26
Indicates that the electric motor 21 stops the rotation speed, a constant rotation speed,
Or, an energization command Sm for instructing a rotation speed according to a height deviation.
Are respectively output via a drive circuit (not shown).

An operation panel 30 for setting and instructing conditions for automatic control of the lift is provided with a target lift setting means 25 for setting a target lift Ht, and a correction height Δh of the load position from the unloading position. And a height correcting means 27 for setting. The target lift setting means 25 includes a lift H from the lift sensor 23.
And the correction height Δh from the height correction means 27 are input. Here, as shown in FIG. 2, the unloading position indicates a position where the fork 13 is inserted into the fork insertion opening of the pallet 32 placed on the plurality of racks 31 at the time of unloading.
The loading position indicates a position that is set higher than the unloading height Hg by the correction height Δh. Here, the unloading height Hg is measured from the fork reference position Rf where the height H is zero.

As shown in FIG. 3, a target lift setting means 25 is provided.
Is a stage number selection switch 25a for selecting the number of stages to be unloaded in a plurality of racks, and a teaching switch 25 that is turned on when teaching the unloading height Hg and the correction height Δh.
b, a loading switch 25c that is turned on when selecting a loading position, and a loading switch 25d that is turned on when selecting a loading position.

Also, as shown in FIG.
Reference numeral 7 denotes a correction height indicator 27a for displaying the set correction height Δh, an increase switch 27b which is turned on when a desired correction height is to be set higher, and a case where the desired correction height is to be set lower. It has a reduction switch 27c, a uniform switch 27d, and an individual switch 27e that are turned on. Here, the uniform switch 26d is turned on when setting the correction height Δh equal to all of the plurality of stages, and the individual switch 27e is turned on when setting the correction height Δh individually for each stage.

Here, the teaching of the unloading height Hg by the target height setting means 25 and the teaching of the correction height Δh by the height correction means 27 will be described. First, the teaching procedure of the unloading height Hg will be described with reference to the detailed view of the target height setting means 25 shown in FIG. When the operator operates the lift lever 22 in a direction in which the fork 13 moves toward a desired position, the fork 13 moves up and down toward the desired position. When the position of the blade edge of the fork reaches the desired height of the fork insertion port of the pallet, the operator sets the lift lever 22 to a neutral position and stops the fork 13 from moving up and down. Next, when the desired number of stages of the stage number selection switch 25a is turned on (for example, the number of stages to be set is the nth stage) and the teaching switch 25b is turned on, the lift H at that time is set to the target lift setting means 25. And stored in the target lift setting means 25 as the n-th stage unloading height Hgn. The remaining number of stages is similarly set and stored in the target lift setting means 25.

Next, the procedure for teaching the correction height Δh will be described with reference to the detailed view of the height correction means 27 shown in FIG. To set a uniform correction height ΔhFIX that is the same for all steps,
When the operator turns on the uniform switch 27d and sets a different individual correction height Δhn for each stage, the operator turns on the individual switch 27e. When the individual switch 27e is turned on, the number of steps to be set is selected by the number-of-steps selection switch 25a of the target lift setting means 25, and then the increase switch 27b or the decrease switch 27c according to the respective number of steps.
To set the individual correction height Δhn from the unloading position. Thereafter, the teaching switch 25 of the target lift setting means 25 is set.
When b is turned on, the target lift setting means 25 takes in and stores the individual correction height Δhn. When the operator turns on the uniform switch 27d, it is not necessary to select the number of stages with the stage number selection setting switch 25a, and the uniform correction height ΔhFIX from the loading position is set by the increase switch 27b or the decrease switch 27c. Thereafter, the teaching switch 25b of the target lift setting means 25 is turned on to store the uniform correction height ΔhFIX in the target lift setting means 25, and the setting is completed.

FIG. 5 shows a procedure for setting the target lift Ht by the target lift setting means 25. In the description of FIG. 5, each step is represented by adding S. First, the operator turns on the unloading switch 25c or the unloading switch 25d (S1). Next, a desired stage number n is selected by the stage number selection setting switch 25a (S2). Furthermore, a uniform switch 27
d or the individual switch 27e is turned on (S3). Thus, after the input by the operator is completed, it is determined in S4 whether the unloading switch 25c is on. If it is on, the stored n-th stage unloading height Hgn is set to the target height H.
t and output to the controller 26 (S5). If the unloading switch 25c is off, it is determined that the loading operation is being performed, and then it is determined whether the uniform switch 27d is on (S6). If it is on, a value obtained by adding the uniform correction height ΔhFIX to the stored n-th stage unloading height Hgn is set as the target lifting Ht (S7) and output to the controller 26. When the uniform switch 27d is off, the value obtained by adding the stored unloading height Hgn stored at the nth stage and the individual correction height Δhn stored corresponding to the nth stage is calculated as the target lift H
t (S8) and output to the controller 26.

According to the present embodiment, the target height setting means stores the unloading height and the uniform correction height in accordance with the teaching from the correction height setting means by the operator, and individually stores the height corresponding to each number of racks. The corrected height is also stored. When the operator selects a loading position as the target lift, the stored lift corresponding to the selected number of stages is set as the target lift. When the operator selects a loading position as the target lift and a uniform height as the correction height, the target lift setting means sets the stored lift and the stored uniform height corresponding to the selected number of stages. The value obtained by adding the corrected height is set as the target lift of the loading position. When the operator selects the loading position as the target lift and individual as the correction height, the target lift setting means corresponds to the unloading height stored in correspondence with the selected number of stages and the number of stages. Then, a value obtained by adding the individually corrected heights individually stored is set as the target lift at the loading position. The set target lift is output to the controller, and when the operator operates the lift lever in a direction in which the fork approaches the target lift, a deviation value between the target lift and the actual lift detected by the lift sensor is calculated. The controller outputs a valve opening command value based on the value to the electromagnetic proportional valve.
Further, the controller outputs a rotation command to the electric motor in order to send pressure oil from the hydraulic pump to the electromagnetic proportional valve. The solenoid proportional valve feeds oil to the lift cylinder and expands and contracts the lift to approach the target lift. When the actual lift approaches the target lift sufficiently, the controller outputs a valve opening command value of zero valve opening to the solenoid proportional valve and a rotation stop command to the electric motor, and the automatic lift control is completed. I do. In this way, not only can the operator set a uniform and uniform correction height in consideration of the actual height of the load on the pallet 32 and the spacing between the racks 31 before the work, but also the load Since the lift can also be set individually, it is possible to obtain an automatic lift control device of a forklift corresponding to various types of packing forms and loading places.

In this embodiment, the height correction means 27
As a method of changing the correction height, a decrease switch 27c and an increase switch 27b are used, but a changeover switch that can select any one of a plurality of different predetermined values set in advance, an analog volume , A dip switch, a numeric key switch, or the like may be used. Further, although the target lift setting means 25 and the height correction means 27 are configured separately, they may be integrally formed in one housing.

As described above, according to the present invention, the target height setting means sets the corrected height of the loading position from the unloading position to the same height for all the steps of the rack by the setting from the height correcting means. The uniform correction height can be stored, and the individual correction height can be stored for each number of stages. The operator can individually set the individual correction height for each number of stages in consideration of the package shape such as the height of the load on the pallet and the interval between racks. As a result, the load does not come into contact with the rack or the like and there is no need to reload the load, so that it is possible to cope with various types of loads and storage locations, and to obtain an automatic lift control device for a forklift with good workability. Can be.

[Brief description of the drawings]

FIG. 1 is a hardware configuration diagram according to the present invention.

FIG. 2 is an explanatory diagram of a loading position and a loading position.

FIG. 3 is an explanatory diagram of target lift setting means.

FIG. 4 is an explanatory diagram of a height correcting unit.

FIG. 5 is a flowchart showing a procedure for setting a target lift by a target lift setting means.

FIG. 6 is an explanatory diagram of a forklift to which the present invention is applied.

[Explanation of symbols]

11: outer rail, 12: inner rail, 13: fork, 14: lift cylinder, 16: solenoid proportional valve, 20
... hydraulic pump, 21 ... electric motor, 22 ... lift lever, 23 ... lift sensor, 24 ... lever operation amount detector, 2
5 Target lift setting means, 26 Controller, 27 Height correction means, 30 Operation panel, 31 Rack, 32
Pallet, Δh: Corrected height, Lev: Lever operation amount, H
t: target lift, H: lift, Sm: energization command, Sv: valve opening command value.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Norihiko Eda 110 Yokokura Nitta, Oyama City, Tochigi Prefecture Komatsu Forklift Co., Ltd. Tochigi Plant F-term (reference) 3F333 AA02 AB13 BA02 BD02 FA21 FA25 FD03 FE09

Claims (2)

[Claims] 1. A lift sensor for detecting a lift of a fork of a forklift, an electromagnetic proportional valve for expanding and contracting a lift cylinder for controlling the lift, a plurality of lifts taught by an operator, and each of the lifts. Corrected height of a fixed value is pre-stored uniformly in the height from the lifting height to the corresponding loading position, and when the operator selects any of the plurality of loading positions, the corrected When the corresponding lifting height is set to the target lifting height and one of the plurality of loading positions is selected, the correction height stored in the corresponding loading height among the plurality of stored lifting heights stored is calculated. A target lift setting means for setting the added load height as a target lift, and a command signal calculated based on a deviation value between the set target lift and the lift detected by the lift sensor, being electromagnetically proportional. Control to output lift to valve to control lift An automatic lift control apparatus for a forklift, comprising: a height correction means that can change a correction height stored in a target lift setting means in accordance with an operator's teaching. High control device. 2. The forklift automatic lift control device according to claim 1, wherein the height correction means is capable of setting a correction height corresponding to each of the plurality of unloading lifts, and the target lift setting means is An automatic lift control device for a forklift, wherein, when an operator selects any of a plurality of load positions, a load height obtained by adding a corresponding lift height and a correction height is set as a target lift. .