JPS6366098A - Fork lifting-position setting method in forklift - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) This invention relates to a method for setting a fork lift height position in a forklift.

(Prior Art) Conventionally, various methods have been proposed for automatically stopping the fork of a forklift at an arbitrary lifting height position.

For example, if you use the keyboard to store in advance the lifting height position you want to stop in memory and move the fork up to that lifting height position, the actual fork position at that time detected by the fork lifting height position detection device It compared the lift height position stored in memory and when they matched, stopped the fork's upward movement.

Further, the fork is manually moved up or down to a predetermined position in advance, and the lift height position indicated by the fork lift height position detection device at that time is stored in the memory. Then, in the same manner as above, the fork is moved upward to the raised height position, and the fork is stopped at the predetermined raised height position based on the fork position detected by the fork raised height position detection device and the raised height position stored in the memory. Met.

(Problems to be Solved by the Invention) However, when setting the lifting height position, it is necessary to accurately measure the desired height in advance. In addition, in the latter case, manual operation is required, so when setting a high lifting height position, it is difficult to accurately judge from the operating position whether the fork is positioned at the predetermined lifting height position. Ta.

That is, in both cases, it is difficult to accurately and easily set the lifting height position.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a method for setting a fork lift height position in a forklift, which can accurately set the lift height position within the cylinder.

Structure of the Invention (Means for Solving Problems) In order to achieve the above-mentioned object, the present invention has a method in which, after inserting a fork into a pallet opening, the fork is moved upward or downward, and the fork is applied to the fork during the movement. The load condition is detected by a fork load detection means, and when a predetermined load condition is reached, the fork lift height value at that time is determined, and based on the same lift height value, the fork lift height for subsequent insertion of the fork into the pallet opening is determined. The gist of the present invention is a method for setting the lift height of a fork in a forklift in which the position is determined.

(Function) After the fork is inserted into the pallet opening by the above means, the fork is moved up or down, and the load condition applied to the fork during that operation is detected by the fork load detection means and determined in advance. When the specified load condition is reached, the fork lift height value at that time is determined, and based on the same lift height value, the fork lift height position for subsequent insertion of the fork into the pallet opening is determined.

(First Embodiment) An embodiment embodying the present invention will be described below with reference to the drawings.

As shown in FIG. 1, an outer mast 3 is supported at the front end of a body frame 2 of a forklift 1 so as to be tiltable in the front-rear direction. The tilt cylinder 4 has its base end rotatably connected to the front upper surface of the vehicle body frame 2, and the tip of the piston rod 4a of the tilt cylinder 4 is rotatably connected to the outside of the outer mast 3. There is.

Therefore, when the outer mast 3 is in the vertical position shown in FIG. 1, when the piston rod 4a of the tilt cylinder 4 is linearly moved, the outer mast 3 is tilted rearward, and conversely, when the piston rod 4 is extended, the outer mast 3 is tilted backward. The outer mast 3 tilted forward.

The lift cylinder 5 is fixedly installed inside the rear side of the outer mast 3, and the tip of its piston rod 5a is connected to the upper rear surface of an inner mast 6 mounted inside the outer mast 3 so as to be movable up and down.

A lift bracket 7 is attached to the inside of the inner mast 6 so as to be movable up and down, and a fork 8 is attached to this bracket 7.

Furthermore, a chain wheel 9 is mounted on the upper part of the inner mast 6.
is rotatably supported, and a chain 10 having one end connected to the upper part of the cylinder body of the lift cylinder 5 and the other end connected to the bracket 7 is hung from the chain wheel 9. Therefore, the piston rod 5 of the shaft cylinder 5
When a is extended and contracted in the vertical direction, the fork 8 is moved up and down via the chain 10.

In addition, the warehouse where the forklift 1 works is provided with a shelf 11 for loading cargo B consisting of multiple stages. Then, the cargo B is loaded and unloaded onto the shelf 11 using the forklift 1. This cargo B is on pallet 12 f
j, transported and stored in a placed state, and the same pallet 12
The fork 1 is inserted into the opening 13 as shown in FIG.

Next, the electrical depiction of the forklift 1 will be explained according to FIG.

A central processing unit (hereinafter referred to as CPU) 14 operates according to a control program stored in a read-only memory (hereinafter referred to as ROM) 15, and performs various operations such as setting the fork lift position. Further, a readable and rewritable memory (hereinafter referred to as RAM) 16 is connected to the CPLJ 14, and the RΔM 16 temporarily stores various calculation results of the CPU 14.

A lift height detection rotary encoder (hereinafter simply referred to as a lift height detection encoder) 17 is provided on the rotating shaft of the chainwheel 9, and this lift height detection encoder 17 sends a signal accompanying the rotation of the chainwheel 9 to the universal counter 1.
Output to 8. The universal counter 18 determines the rotational direction of the chainwheel 9 based on the input timing of the signal from the lifting height detection encoder 17, and counts the number of counts corresponding to the rotation of the chainwheel 9 (corresponding to the height of the fork 8). . The CPU 14 then receives a universal counter 18 via one parallel interface.
A count value is input from , and the lift height value of the fork 8 at that time is determined based on the count value.

Further, a keyboard 20 is disposed in the driver's seat, and a plurality of keys including an automatic lift height setting key 20a and an automatic lift start key 20b are arranged on the keyboard 20. When setting the automatic lifting height setting mode for automatically determining the lifting height position of the fork 8 to the pallet opening 13, the automatic lifting height setting key 20a is also used to select the desired pallet after setting. When starting the movement of the lift 8 toward the opening 13, the automatic lift start key 20b is operated, and the CPU 14 inputs each signal via the parallel interface 21.

Further, the CPU 14 causes the display 22 to display data inputted using the keyboard 20 via the parallel interface 23.

The lift lever 24 and the tilt lever 25 are provided with operation amount detectors 26 and 27, respectively.
6.27 outputs a signal corresponding to the operation ω of the lift lever 24 and tilt lever 25 to the A/D converter 28. The CPU 14 inputs the signals converted by the A/D converter 28 via two parallel interfaces, and determines the operating amounts of the lift lever 24 and tilt lever 25 based on the signals.

The lift cylinder drive circuit 30 supplies and drains hydraulic oil from the cylinder 5 to drive the lift cylinder 5, and the cylinder drive circuit 3OG and tCPU1 are connected to the same lift 1.
4 through the parallel interface 31 and the D/A converter 32. This signal causes the fork 8 to move at a speed corresponding to the amount of operation of the lift lever 24.
move up and down.

Further, in the automatic lifting height setting mode, the CPU 14 moves the fork 8 up and down by one unit (1 mm in this embodiment) regardless of the operation of the lift lever 24, and furthermore, when the automatic lifting height start key 20b is operated. When the fork 8 is lifted up, the fork 8 is moved up and down to reach the set fork lift height position.

The tilt cylinder drive circuit 33 supplies and drains hydraulic oil from the tilt cylinder 4 to drive the tilt cylinder 4.
The tilt lever 25 is controlled by the control signal inputted through 2.
Tilt the fork 8 at a speed corresponding to the amount of operation (
Tilt 8).

A lift cylinder oil pressure detector 34 serving as a fork load detection means detects the lift cylinder 5 and the lift cylinder drive circuit 3.
The oil pressure detector 34 detects the oil pressure of the hydraulic oil in the lift cylinder 5 and outputs a signal corresponding to the oil pressure.

Then, the CPU 14 receives the signal from the oil pressure detector 34 as A.
The load condition applied to the fork 8 is detected by inputting the signal through the /D converter 35 and the parallel interface 29. Furthermore, the CPU 14 determines whether a predetermined load condition has been reached. In other words, the oil pressure in a no-load state where no cargo B or the like is placed on the fork 8 is zero, and the fork 8 is set to have a positive oil pressure when a load is applied to the fork 8 compared to that no-load state, or when the fork 8 is in a no-load state. Determine whether the load has decreased and the oil pressure has become negative. Based on this judgment, the CPU 14 moves the fork 8 to the pallet opening 13 in the automatic lifting height setting mode.
It is determined whether it is in contact with the upper surface 13a or lower surface 13b of (see FIG. 2).

And CPU 14, ROM 15, RAM 16, parallel interface 19.21, 23.29.31,
Universal counter 18, display 22, A/D
The converters 28, 35 and the D/A converter 32 constitute a microcomputer 36.

Next, the operation of the microcomputer 36 configured as described above will be explained based on FIG. 4.

The CPU 14 places the fork 8 in a horizontal state and positions it in front of the opening 13 of the pallet 1-12 by operating the lift lever 24 and tilt lever 25 by the driver. That is, the CPU 14 controls the lift lever 24 of the driver.
The operation of the tilt lever 25 is detected by the operation amount detector 26.
The fork 8 is indexed by the signal from 27, and the lift and tilt drive circuits 30 and 33 are controlled to move the fork 8 up and down at a speed corresponding to the lever operation! +J (lift operation) and tilt the mast 3.6 to position the horizontal fork 8 in front of the opening 13 of the pallet 12.

Then, the CPU 14 sets the automatic lifting height setting mode when the automatic lifting height setting key 20a of the keyboard 20 is turned on with the horizontal fork 8 inserted into the opening 13 of the pallet 12.

By operating the same key, the CPU 14 determines whether or not the fork 8 is in contact with the upper surface 13a of the pallet opening 13 at this time. That is, if the oil pressure at that time is a positive value based on the signal from the lift I cylinder oil pressure detector 34 and a load is being applied to the fork 8, it is determined that the fork 8 is in contact with the upper surface 13a of the pallet opening.

Then, if the fork 8 is not in contact with the upper surface 13a of the pallet opening, the CPU 14 moves the fork 8 upward by one unit (1 mm).

Then, in this state, the CPLJ 14 determines whether the fork 8 is in contact with the upper surface 13a of the pallet opening.

Similarly, the CPU 14 moves the fork 8 upward one unit (1 mm) at a time until the fork 8 comes into contact with the upper surface 13a of the pallet opening.

When the fork 8 comes into contact with the upper surface 13a of the pallet opening, the CPU 14 stores the lifting height value at that time in the RAM 16 as the lifting height value 1-1u of the upper surface of the pallet opening.

Furthermore, CPU14 is now one unit (1 mm)
Move the fork 8 downward one by one until the fork 8 touches the lower surface 1 of the opening.
3b, the lower surface 13 of the pallet opening is determined.
If it touches b, the fork lifting height value at that time is added to the lower surface lifting height of the pallet opening and is stored in the RAM 16.

The CPU 14 determines the fork lift height position for inserting the fork into the pallet opening 13 based on the two values (pallet opening upper surface lift value HLJ and pallet opening lower surface lift value IJ2) stored in the RAM 16. Determine the center lift value) Hm. That is, this position) -1m is the lift height IU HLJ.

It is calculated as the additive average value of Hffl (CHu+) - IL)/2) (see Figure 2).

Furthermore, the CPtJ14 stores this pallet opening center lift height value of 1-1m in the RAM16, and also stores its position H.
Raise it one unit (1 mm) at a time so that the fork 8 is located at m.

Further, when the automatic lifting height setting key 20a is pressed, if the fork 8 is in contact with the lower surface 13a of the pallet opening, the CPU 14 lowers the lifting height of the fork 8 by one unit (1 mm). is the lower surface 13b of the pallet opening
If it touches the lower surface 13a, the lift height value at that time is determined as the lift height of the lower surface of the pallet opening ffl+-(J2.
and stores it in the RAM 16. Further, the fork 8 is moved upward one unit (1 mm), and when it is determined that the fork 8 is in contact with the upper surface 13a of the pallet opening, the Ul.
The lift height kTi of the lift A is stored in the RΔN 116 as the pallet i-lower surface IQ high value t-I u L.

The CPU 14 stores two 6fTs stored in this RAM 16.
(Pallet opening top surface 1'; A height 1 straight Hu and pallet opening bottom surface 1aal+1lljHfL) ノ) JOi average 1111 (<Hu 2 Hi)/21 for fork insertion; Q high position (pallet opening center lift) High III) Interject as Hm.

Furthermore, the CPU 14 controls the pallet opening center QD.
Li? I Hm is stored in the RAM 16, and the fork 8 is positioned at the lifting height position Hm by one unit (
1 millimeter) at a time.

Therefore, this lifting height position Hm1. :The second fork is
As shown in the figure, the upper surface of the fork 8 and the upper surface of the opening 13a
The distance d1 between the fork 8 and the distance d2 between the lower surface of the fork 8 and the lower surface 13b of the opening are equal to each other and become the optimal fork insertion height.

Then, when the pallet opening center 19 high position Hm is determined, the CPtJ 14 clears the automatic lifting height setting mode.

After determining the fork lifting height position (pallet opening center lifting height value) Hm in this way.

When the automatic lift height key 20b on the keyboard 20 is pressed, the CPU 14 automatically controls the lift cylinder drive circuit 34 to automatically move the fork 8 to the center of the pallet opening.

Therefore, conventionally, when the driver set the lift height position for inserting the fork, it was necessary to measure it accurately, but there is no need to measure the actual height, and the fork 8 can be moved from the pallet 1 to the open position. Automatic lift height setting key 2 when inserted into section 13
Just press 0a to automatically adjust the height of the barrel from 1 to center of opening H.
m can be set. In addition, in the past, when setting the fork 8 at a high position, it was difficult to judge from the driver's seat whether the fork 8 was in the set position, but this
In the example, the center position of the barre 1 to I71 portion 13 can be accurately determined and the fork 8 can be easily set at that height.

(Second Embodiment) Next, a second embodiment embodying the present invention will be described with reference to FIG. 5.

In this embodiment, when setting the fork lifting height position, the fork 8 is moved up and down in the pallet opening 13 by hand 8 operation to set the fork lifting height ff1Hu, H, 9 at J5 on the upper surface 13a and the lower surface 131). Do what you ask.

That is, with the horizontal fork 8 inserted into the opening 13 of the pallet 12, the fork 8 is moved upward by operating the operation lever 12. When the CPU 14 determines that the lift 8 is in contact with the upper surface 13a of the pallet opening based on the oil pressure detection signal from the lift cylinder oil pressure detector 34, the CPU 14 converts the lifting height (D) at that time into the lifting height value Hu of the upper surface of the pallet opening. Furthermore, when the fork 8 is moved downward by the driver's lever operation and it is determined that the fork 8 has touched the lower surface 131 of the pallet opening based on the oil pressure detected by the lift cylinder oil pressure detector 34, the The elevation value is stored in the palette as the opening lower surface elevation value +1.

Then, the CPU 14 determines the lifting height of the stomach (pallet opening Center lift value) Hm (
= (HU+HJ2)/2) and store it in the RAM 16.

(Third Embodiment) To explain the third actual flow example embodying this invention, RO
The opening height D of the opening 13 of the pallet 12 and the thickness t of the fork 8 shown in FIG. 2 are stored in M15 in advance.

Then, as shown in FIG. 6, with the horizontal fork 714 inserted into the opening 13 of the pallet 120, the fork 8 is moved upward by the operator's lever operation. The CPtJ14 then moves the fork 8 to the upper surface 1 of the pallet opening based on the oil pressure detection signal from the lift cylinder oil pressure detector 34.
3a, the lift height value at that time is stored as the pallet opening upper surface 11 high value HU. Furthermore, C
The PU 14 uses this value 1-1u, the opening height D of the pallet opening 13 and the thickness t of the fork 8 stored in the ROM 15.
Based on the following formula, the fork lift height position (pallet opening center lift height value) 1-1 m is calculated and stored in the RAM 16.

1-1m=Hu-CD-t)/2...(1) Therefore, in this embodiment, the fork lift height position (pallet opening Center lift value) Hm can be set.

In addition, in this third embodiment, the upper surface 1 of the pallet opening
3a is judged, and the pallet opening upper surface elevation value H is determined.
Although u is determined, it may be determined that the pallet opening lower surface 13b is in contact with the pallet opening lower surface elevation value HfL.

That is, the fork 8 is moved downward by the driver's lever operation, and the lift height value when the fork 8 contacts the lower surface 13b of the pallet opening is stored as the pallet opening upper surface lift value H1. Furthermore, this value Hf, the opening height D of the pallet opening 13 stored in the ROM 15, and the thickness t of the fork 8
The fork lifting height position (lifting height value at the center of opening to pallet 1) Hm may be calculated based on the following formula and stored in the RAM 16.

Hm=H1+ <0-t>/2-----・-(2) Also,
By detecting either the pallet opening top surface elevation value Hu at the pallet opening top surface 13a or the pallet opening top surface elevation value HL at the bottom surface 13b of the pallet opening, the equation (1) or equation (2) can be obtained. Calculate the fork lift height position (pallet opening center lift height value) Hm, and set R, A
It may also be stored in M16.

Further, the present invention is not limited to the above-mentioned embodiments; for example, although the opening 13 of the pallet described above is surrounded on all four sides (mouth-shaped), it is also possible to use a mouth-shaped opening with an open bottom surface. It may be embodied in a pallet having a portion.

Further, in each of the above embodiments, the fork lift height position for inserting the fork was based on the upper surface of the fork 8, but it may be based on the lower surface of the fork 8 or the height of the fork 8 may be
The center position of the direction may be used as a reference.

Furthermore, in addition to the lift cylinder oil pressure detector 34, the fork load detection means may be a pressure sensor embedded in the upper and lower surfaces of the fork 8 to detect the applied pressure.

Effects of the Invention As described in detail above, this invention has an excellent advantage in that the height position of the fork can be easily and accurately set simply by moving the fork up or down while the fork is inserted into the pallet opening. be effective.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a forklift embodying the present invention, FIG. 2 is a diagram showing a fork inserted into the opening of a pallet, FIG. 3 is a block circuit diagram showing the electrical configuration of the forklift, and FIG. 5 is a flowchart showing the action of the second embodiment, and FIG. 6 is a flowchart showing the action of the third embodiment. In the figure, 1 is a forklift, 8 is a fork, 12 is a pallet, 13 is an opening of the pallet, 13a is the upper surface of the pallet opening, 13b is the lower surface of the pallet opening, 14 is a central processing unit (CPU), and 15 is a read-only memory. (ROM)
, 16 is a readable and rewritable memory (RAM),
17 is an encoder for detecting lift height, 34 is a lift cylinder oil pressure detector as a fork load detection means, Hu is a pallet opening top surface lift value, H°C is a pallet opening bottom surface lift value, )-1m is a fork lift height position ( (height value at the center of the pallet opening). Patent applicant Toyota Industries Corporation representative
Patent Attorney's Death Day Hiroxuan Hu HmHJ! Figure 5 Figure 6

Claims (1)

[Claims] 1. After the fork is inserted into the pallet opening, the fork is moved up or down, and the fork load detection means detects the load condition applied to the fork during the movement and detects the predetermined load. A method for setting a fork lift height position in a forklift, which calculates a fork lift height value at that time when a condition is reached, and determines a fork lift height position for subsequent insertion of the fork into the pallet opening based on the same lift height value. . 2. The fork lift height position is determined by detecting the load on the fork that occurs when the fork touches the top surface of the pallet opening.The fork lift height position when the fork touches the top surface is defined as the pallet opening top surface lift height, and the fork lifts when the fork touches the top surface of the pallet opening. The load on the fork that occurs when it comes into contact with the lower surface is detected, and the lift height position of the fork when it comes into contact with the lower surface is defined as the lift height value of the lower surface of the pallet opening, and the added average value of the lift height values of the upper surface and the lower surface is claimed in claim 1. A method for setting a fork lift height position in a forklift according to item 1. 3. Fork lifting height position detects the load on the fork that occurs when the fork touches the top surface of the pallet opening, and the fork lifting height position when it touches the top surface is defined as the pallet opening top surface lifting height value, and the fork lifts when the fork touches the top surface of the pallet opening. The load on the fork that occurs when it comes into contact with the lower surface is detected, and the lift height position of the fork when it comes into contact with the lower surface is taken as the lower surface lift value of the pallet opening, and one of these values is combined with the predetermined height of the pallet opening and A method for setting a fork lift height position in a forklift according to claim 1, wherein the fork lift height position is determined by the thickness of the fork.