JP2000318997A - Tilt automatic level control device for fork lift - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely hold a fork in a tilt horizontal position by determining a tilt horizontal angle correction target value required for the calculation of a solenoid proportional command signal by adding a calculated correction quantity to a tilt horizontal angle target value preliminarily stored or set by an operator. SOLUTION: A controller 40 has a memory part for the tilt horizontal angle target value of a fork 12 and a tilt level control means 45 for automatically controlling the tilt angle. A level control part 44 adds a correction quantity A Δθ of input tilt angle to a tilt horizontal angle target value preliminarily stored or set by an operator to calculate a tilt horizontal angle correction target value, and outputs the deviation between this tilt horizontal angle correction target value and the actual tilt angle detected by a tilt angle sensor to a drive part 41. The drive part 41 outputs a valve opening command or valve closing command according to the angle deviation to a solenoid proportional valve for driving a tilt cylinder on the basis of the deviation calculated by the level control part 44, and outputs a current-carrying ON/OFF signal to an electric motor drive unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic tilt control device for automatically setting a fork of a forklift to a tilt horizontal position.

[0002]

FIG. 20 is a side view showing an example of a forklift 1 to which the present invention is applied. At the front of a body frame 4 having a pair of left and right front wheels 2, 2 and a pair of right and left rear wheels 3, 3, a work machine device 5 called a double mast type for loading and lifting loads is provided. That is, the outer rail 10 is provided upright at the front of the body frame 4 so as to be tiltable in the front-rear direction. The body frame 4 and the outer rail 10 are connected by two tilt cylinders 14 attached to the left and right sides of the vehicle body, and the outer rail 10 is tilted in the front-rear direction by expanding and contracting the tilt cylinder 14. An inner rail 11 is inserted into the outer rail 10 so as to be able to move up and down, and a fork 12 for loading a load is mounted on the inner rail 11.
Are attached along the inner rail 11 so as to be movable up and down. A lift cylinder 15 that raises and lowers the inner rail 11 is disposed on the rear surface of the outer rail 10. The inner rail 11 and the fork 12 move up and down by expanding and contracting the lift cylinder 15. Body frame 4
A tilt lever 2 for extending and retracting the tilt cylinder 14 is provided on an operation unit in front of a driver's seat 20 provided at a substantially central portion of the tilt lever 2.
1 and a lift lever 22 for extending and retracting the lift cylinder 15 are provided.

The fork 12 is mounted at right angles to an inner rail 11 that supports the fork 12 so as to be able to move up and down.
When the inner rail 11 is in the vertical posture, the fork 12 is horizontal, and when the inner rail 11 is tilted in the front-rear direction, the fork 12 is also tilted up and down with respect to the horizontal plane. When taking a load placed on a rack or the like during work, if the fork 12 is tilted by a predetermined angle or more, the fork 12 cannot be inserted well into the lower gap of the pallet, and the fork 12 and the pallet interfere with each other to load the load. There is a risk of damage and collapse. For this purpose, the apparatus has a tilt horizontal automatic control device that automatically controls the tilt angle of the fork 12 to be within a predetermined angle.

[0004]

However, the above configuration has the following problems. FIG.
FIG. 4 is a configuration diagram illustrating an assembled state of the inner rail 11, the outer rails 10, 10, and the forks 12, and illustrates a state when the inner rail is lowered. An inner rail 11 having a U-shaped cross section is inserted into the outer rail 10 having a U-shaped cross section so as to be vertically movable. An outer rail roller 10a is attached to the upper end of the outer rail 10, and contacts the inside of the inner rail 11 having a U-shaped cross section to form the inner rail 1.
Guides one. An inner rail roller 11a is attached to the lower end of the inner rail 11, so that the inner rail roller 11a contacts and guides the inside of the outer rail 10 having a U-shaped cross section. The inner rail 11 is located between the inner side of the outer rail 10 and the inner rail roller 11a.
Is provided with a rail gap a in order to slide smoothly. When the inner rail 11 descends, the longitudinal distance between the outer rail roller 10a and the inner rail roller 11a is b. Two finger board rollers 12a, 12a are rotatably inserted into the inner rail 11, and a fork 12 is attached to a finger board 12b supporting the finger board rollers 12a, 12a. 11 can be moved up and down.

FIG. 22 shows a state where the inner rail 11 and the fork 12 are raised. When the inner rail 11 is raised as shown in the figure, the outer rail roller 10a
The distance c between the inner rail 11a and the inner rail roller 11a in the longitudinal direction is shorter than the above-described distance b. Therefore, the inner rail 11 is inclined forward by the rail gap a with respect to the outer rail 10. At this time, the inclination angle Δθc is calculated by the equation “Δθc = tan”
-1 (a / c) ", and the fork 12 is inclined forward with respect to the outer rail 10 by the inclination angle Δθc. That is, the higher the lift of the fork 12, the greater the tilt angle. Therefore, the tilt angle of the fork 12 is larger than the tilt angle of the outer rail 10, and as described above, even if the tilt horizontal position of the fork 12 is determined based on the tilt angle of the outer rail 10, the fork 12 is still inclined forward. It will be.

An object of the present invention is to provide an automatic tilt control apparatus for a forklift capable of holding a fork at a correct tilt horizontal position regardless of the lift of the fork, focusing on the above-mentioned problems.

[0007]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a tilt angle sensor for detecting a tilt angle value of a fork of a forklift, and a tilt cylinder for controlling a tilt angle. An electromagnetic proportional valve and a command signal calculated based on a deviation value between a tilt horizontal angle target value previously stored in a storage unit or set by an operator and a tilt angle value detected by a tilt angle sensor are output to the electromagnetic proportional valve. An automatic level control device for a forklift equipped with a tilt level control unit having a level control unit for controlling a tilt angle by using a height sensor for detecting a height of a fork. And a correction amount calculation unit for calculating a correction amount of the tilt angle in accordance with the lift detected by the control unit. The tilt horizontal angle correction target value required for the calculation of the valve command signal is stored in advance in the storage unit, or the correction amount calculated by the correction amount calculation unit is added to the tilt horizontal angle target value set by the operator. .

According to the present invention, correction data such as a table or a relational expression indicating the relationship between the height and the correction amount is stored in advance in the correction amount calculation section of the tilt horizontal control means, and the correction amount calculation section stores the correction data. To calculate a correction amount corresponding to the lift. The horizontal control unit of the tilt horizontal control means adds the correction amount calculated by the correction amount calculation unit to the tilt horizontal angle target value to obtain a tilt horizontal angle correction target value. Next, the horizontal control section of the tilt horizontal control means outputs to the electromagnetic proportional valve a command signal calculated based on the tilt horizontal angle correction target value and the tilt angle detected by the tilt angle sensor. As a result, pressure oil is sent from the electromagnetic proportional valve to the tilt cylinder, and the tilt cylinder expands and contracts so that the tilt angle of the fork becomes horizontal. When the deviation between the tilt horizontal angle correction target value and the tilt angle detected by the tilt angle sensor is smaller than a predetermined difference, the valve opening becomes zero. The valve opening command is output to the electromagnetic proportional valve, and the tilt automatic horizontal control is performed. Is completed. As described above, since the tilt horizontal angle target value of the fork is corrected according to the lift, the fork can be controlled to the correct tilt horizontal position regardless of the lift of the fork. Therefore, when unloading a load placed on a rack or the like, the fork is set horizontally, so that the fork can be efficiently inserted into the fork insertion port of the pallet even at a high lift position without interference between the fork and the pallet. In addition, it is possible to obtain a forklift tilt automatic horizontal control device with excellent work efficiency without load collapse.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. First, Figures 1, 2, 3,
4, the first embodiment will be described. FIG. 1 shows a working machine device called a double-mast type forklift, which is an object of the present embodiment. The same components as those in FIG. 20 will be described with the same reference numerals. The outer rail 10 is connected to a tilt cylinder 14, and tilts in the front-rear direction by expanding and contracting the tilt cylinder 14. Inner rail 11
Is attached to the outer rail 10 so as to be able to move up and down, and a fork 12 is attached to the inner rail 11 so as to be able to move up and down.
A chain sprocket 17 is attached to the tip of a cylinder rod 16 of the lift cylinder 15. The outer rail 10 and the fork 12 are connected to the chain sprocket 1
7 are connected by a chain 18 looped around.
Therefore, when the lift cylinder 15 is extended, the inner rail 11 rises along the outer rail 10 and
The fork 12 rises along the inner rail 11 at twice the speed of the inner rail 11. The discharge circuit 33 of the hydraulic pump 31 driven by the electric motor 30 is connected to an electromagnetic proportional valve 32 that controls expansion and contraction of the tilt cylinder 14 and the lift cylinder 15. The electromagnetic proportional valve 32 includes a tilt cylinder 1 by a tilt backward tilt circuit 34 and a tilt forward tilt circuit 35.
4 and connected to the lift cylinder 15 by a lifting circuit 36. 38 is an oil tank.
The vehicle body is provided with a tilt angle sensor 23 for detecting a tilt angle of the outer rail 10. Near the lower end of the outer rail 10, there is provided an origin limit switch (hereinafter referred to as origin LS) 26 which is turned on when the fork 12 comes near the lowermost position and defines the origin of the position of the fork 12. The outer rail 10 has a fork 1 for measuring the distance between the outer rail 10 and the inner rail 11.
A lift sensor 25, which is one of the two lift detecting means, is provided. The lift sensor 25 uses, for example, a reel-type incremental encoder that measures the length by the length of the unwound wire. One end of the wire forming the reel is connected to the inner rail 11. The height of the fork 12 from the origin LS26 can be obtained by combining the height sensor 25 and the origin LS26.

FIG. 2 is a block diagram of the control system. The controller 40 is connected to the tilt lever 21, the lift lever 22, the tilt angle sensor 23, the tilt automatic switch 24, the lift sensor 25, and the origin LS26, and inputs signals from each. The tilt automatic switch 24 is provided at the operator's hand and is operated when performing automatic tilt horizontal control. The controller 40 is provided with the electromagnetic proportional valve 3
2. Connect to the electric motor driving device 37 and output a predetermined control signal to each. The electromagnetic proportional valve 32 is a general term for tilt and lift electromagnetic proportional valves. The electric motor driving device 37 is connected to the electric motor 30, and the controller 40
ON of the power supply to the electric motor 30 by the control signal from
Performs off control. The electric motor 30 drives the hydraulic pump 31, and the discharge circuit 33 of the hydraulic pump 31
Connected to The tilt backward tilt circuit 34 from the electromagnetic proportional valve 32 is connected to the head side of the tilt cylinder 14, and the tilt forward tilt circuit 35 is connected to the bottom side of the tilt cylinder 14. The elevating circuit 36 from the electromagnetic proportional valve 32 is connected to the bottom side of the lift cylinder 15. The head side of the lift cylinder 15 is connected to an oil tank (not shown). The electromagnetic proportional valve 32 is switched to a predetermined operation position by a control signal from the controller 40, and controls expansion and contraction of the tilt cylinder 14 and expansion and contraction of the lift cylinder 15.

The controller 40 has a storage unit for storing a tilt horizontal angle target value of the fork 12, and a tilt horizontal control means 45 for automatically controlling the tilt angle. The storage unit stores a predetermined tilt horizontal angle target value in advance. Also, a tilt horizontal angle target value set by the operator using a predetermined setting means is stored. FIG. 3 shows the tilt horizontal control means 45. The tilt horizontal control unit 45 has a correction amount calculation unit 43 and a horizontal control unit 44. Here, the correction amount calculation unit 43 calculates a correction amount Δθ of the tilt angle according to the lift of the fork 12. As described above, the forward tilt angle of the fork 12 increases with the lift. Therefore, in order to make the fork 12 horizontal, it is necessary to correct the tilt horizontal angle target value of the outer rail 10 so that the fork 12 is tilted rearward as the fork 12 lifts. FIG. 4 is a graph showing the relationship between the lift position of the fork 12 and the correction amount of the tilt horizontal angle target value. The vertical axis of the graph is the correction amount Δθ, and the horizontal axis is the lifting position of the fork 12. As shown in the graph, the correction amount Δθ increases in proportion to the lift position. This graph is obtained in advance by calculation or experiment, and the correction amount calculation unit 43
To be stored. The correction amount calculation unit 43 calculates a correction amount Δθ based on the input lift position of the fork 12,
Output to the horizontal control unit 44. Here, the direction of the tilt angle is positive in the backward tilt direction. As a method of storing the relationship between the height and the tilt angle correction amount in advance, either a method of storing the above graph as a data table or a method of storing the graph by approximating it with a predetermined relational expression, or the like. However, there is no particular limitation. The horizontal control unit 44 calculates the tilt horizontal angle correction target value by adding the input tilt angle correction amount Δθ and the tilt horizontal angle target value previously stored in the storage unit or set by the operator. A deviation value between the horizontal angle correction target value and the actual tilt angle detected by the tilt angle sensor is output to the drive unit 41. Drive unit 41
Outputs a valve opening command or a valve closing command corresponding to the angle deviation value to the electromagnetic proportional valve 32 that drives the tilt cylinder 14 based on the deviation value calculated by the horizontal control unit 44, and outputs the command to the electric motor driving device 37. Outputs a command to turn on or off the current.

Next, the automatic tilt control procedure is shown in FIGS.
4 will be described. First, a procedure for setting the fork 12 to the lift for performing the tilt automatic horizontal control will be described. When the operator raises the lift lever 22, the controller 4
0 outputs a control signal to the electromagnetic proportional valve 32 to switch to the ascending position. At the same time, an ON command is output to the electric motor driving device 37 to energize the electric motor 30. The electric motor 30 operates to drive the hydraulic pump 31, and the pressure oil is supplied to the discharge circuit 33.
Is supplied to the bottom side of the lift cylinder 15 through the electromagnetic proportional valve 32 and the elevating circuit 36. Lift cylinder 1
5, the inner rail 11 and the fork 12 rise. When the operator operates the lift lever 22 to the neutral position, the controller 40 outputs a valve opening command of the valve opening zero value to the electromagnetic proportional valve 32, and the electromagnetic proportional valve stops the discharge of the pressure oil. At the same time, a stop signal is output to the electric motor driving device 37 to stop the energization of the electric motor 30 and the hydraulic pump 31
Stop driving. When the operator lowers the lift lever 22, the electromagnetic proportional valve 32 is switched to the lowered position, and the oil on the bottom side of the lift cylinder 15 is discharged from the electromagnetic proportional valve 3.
2, the inner rail 11 and the fork 12 are lowered by their own weight. With these procedures, the fork 12 is raised and lowered to set a desired lift.

The procedure of the automatic tilt level control after setting the fork 12 to a desired lift will be described. The tilt horizontal angle target value is initially set to a zero value. The operator turns on the tilt automatic switch 24 and sets the tilt lever 2
1 is operated in the direction in which the deviation angle between the tilt horizontal angle target value and the actual angle is reduced. The correction amount calculation unit 43 includes the lift sensor 2
5, the correction amount Δθ of the target value is calculated based on the previously stored graph shown in FIG. 4, the correction amount Δθ is added to the tilt horizontal angle target value, and the tilt horizontal angle correction target value is calculated. Ask. Then, the calculated tilt horizontal angle correction target value is compared with the actual tilt angle input from the tilt angle sensor 23. If the actual tilt angle does not reach the tilt horizontal angle correction target value, the horizontal control unit 44 is used. Outputs an energization ON command to the electric motor driving device 37 via the driving unit 41 to energize the electric motor 30 to drive the hydraulic pump 31 and to instruct the electromagnetic proportional valve 32 to open the valve according to the angle deviation value. Is output to extend and retract the tilt cylinder 14 to tilt the outer rail 10 in a predetermined direction. When the tilt angle of the outer rail 10 reaches the tilt horizontal angle correction target value, the controller 40 outputs an energization off command from the horizontal control unit 44 to the electric motor driving device 37 via the driving unit 41 to energize the electric motor 30. Stop and stop the hydraulic pump drive. At the same time, a valve opening command of a valve opening zero value is output to the electromagnetic proportional control valve 32 to stop the expansion and contraction of the tilt cylinder 14 and stop the tilt operation of the outer rail 10.

Next, a second embodiment will be described with reference to FIGS. 5, 6, 7, 8, 9, and 10. FIG. 5 shows a working machine device called a triple-mast type forklift, which is an object of the present embodiment. The same components as those of the double-mast type working machine shown in FIG. 1 described in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Only different parts will be described. A middle rail 13 is provided between the outer rail 10 and the inner rail 11, and the outer rail 10 and the middle rail 13
Is provided with a second lift cylinder 15b. The outer rail 10 and the inner rail 11 are connected by a chain 18a looped around a chain sprocket 17a attached to the upper end of the middle rail 13. Therefore, when the second lift cylinder 15b expands and contracts, the middle rail 13 and the inner rail 11 move up and down at the same time. The inner rail 11 has a first lift cylinder 15
a is attached, and a chain sprocket 17 is provided at the tip of the cylinder rod 16. Inner rail 1
1 and the fork 12 are connected by a chain 18 wrapped around a chain sprocket 17, and the fork 12 moves up and down by expansion and contraction of the first lift cylinder 15a. An elevating circuit 36 from the electromagnetic proportional valve 32 is connected to the bottom side of the first lift cylinder 15a and the second lift cylinder 15b. When pressure oil is supplied, the first lift cylinder 15a first expands, and the first lift cylinder 15a extends. When the cylinder 15a reaches the stroke end, the second lift cylinder 15b
Stretches. A first lift sensor 25 is provided on the inner rail 11.
a is attached, and the lift of the fork 12 is detected. A second lift sensor 25b is attached to the outer rail 10, and the second lift sensor 25b
From the stroke of the lift cylinder 15b to the inner rail 1
1 is detected.

FIG. 6 shows another working machine device of the present embodiment, which is referred to as a full forklift type forklift. The same components as those of the double-mast type working machine shown in FIG. 1 described in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Only different parts will be described. The outer rail 10 and the inner rail 11 are connected by a second lift cylinder 15b, and the inner rail 11 moves up and down by expansion and contraction of the second lift cylinder 15b. Inner rail 1
1 is provided with a first lift cylinder 15a, and a chain sprocket 17 is attached to the tip of a cylinder rod 16. The fork 12 and the inner frame 11 are connected to a chain 18
The fork 12 is moved up and down by expansion and contraction of the first lift cylinder 15a. The second lift sensor 25b attached to the outer rail 10 detects the lift of the inner rail 11, and the first lift sensor 25a attached to the inner rail 11 detects the stroke of the first lift cylinder 15a. To detect the lift of the fork 12.

FIG. 7 shows a block diagram of the control system. The same components as those of the control system block diagram shown in FIG. 2 described in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Only different portions will be described. The controller 40 includes a tilt lever 21, a tilt automatic switch 24, a first lift sensor 2
5a, the second elevation sensor 25b, the origin LS26, and the tilt angle sensor 23. The illustration of the lift lever 22 and the lift cylinder 15 is omitted. Note that the controller 40 has a storage unit and a horizontal control unit 45 as in the first embodiment.

FIG. 8 shows the tilt horizontal control means 45. Similar to FIG. 3 described in the first embodiment, the tilt horizontal control unit 45 has a correction amount calculation unit 43 and a horizontal control unit 44. Here, the correction amount calculator 43 calculates a first-stage correction amount Δθ1 and a second-stage correction amount Δθ2 of the tilt angle corresponding to the lift of the fork 12. FIG. 9 shows the first lift sensor 25a.
Showing the relationship between the lift position (first-stage lift position) of the fork 12 detected from the above and the correction amount (first-stage correction amount) Δθ1 of the tilt horizontal angle target value obtained according to the lift position. It is. FIG. 10 shows the lift position of the inner rail 11 detected by the second lift sensor 25b (second lift position).
7 is a graph showing the relationship between the tilt horizontal angle correction amount (second-stage correction amount) Δθ2. First-stage correction amounts Δθ1 and 2
The stage correction amount Δθ2 is obtained in advance by calculation or experiment and stored in the correction amount calculation unit 43. As in the previous embodiment, as a method of storing the relationship between the elevation and the tilt angle correction amount in advance, a method of storing the above graph as a data table or an approximate method using a predetermined relational expression is used. Any method such as storage may be used, and there is no particular limitation. The correction amount calculation unit 43 calculates the correction amount Δθ1 and the correction amount Δθ2 based on the input lift position of the fork 12, and outputs the correction amount Δθ1 and the correction amount Δθ2 to the horizontal control unit 44. Note that the horizontal control unit 44
This is the same as the horizontal control unit 44 of the embodiment, and the description is omitted.

Next, the tilt automatic horizontal control procedure is shown in FIG.
This will be described with reference to FIGS. The operator turns on the tilt automatic switch 24 shown in FIG.
When the operator operates the first lift sensor 2, the correction amount calculator 43
The detection signal from 5a is input, and the first-stage target value correction amount Δθ1 is calculated from the graph of FIG. Next, the detection signal from the second lift sensor 25b is input, and 2 is obtained from the graph of FIG.
The step target value correction amount Δθ2 is calculated. And Δθ1 and Δ
The sum of θ2 and Δθ is added to the tilt horizontal angle target value as a correction amount as shown in the horizontal control unit 44 in FIG. The subsequent operation is the same as in the first embodiment described with reference to FIG.

According to the first and second embodiments, the forward inclination of the fork caused by the structural gap between the outer rail and the inner rail is controlled by controlling the tilt angle horizontally by a correction amount calculated according to the lift. I have. The correction amount is calculated from a relationship graph between the lift and the correction amount obtained in advance by a calculation or an actual vehicle test. Note that this relation graph is stored in advance in the correction amount calculation unit. For a work machine with a single lift cylinder, one correction amount is added to the tilt horizontal angle target value, and for a work machine with two lift cylinders, two correction amounts are added to the tilt horizontal angle target value. To calculate a tilt horizontal angle correction target value. When the operator turns on the tilt automatic switch and operates the tilt lever in the direction in which the fork tilts backward, oil is supplied in the direction in which the tilt cylinder tilts backward from the electromagnetic proportional valve that controls the expansion and contraction of the tilt cylinder. Approaches the horizontal posture from the forward leaning posture. When the difference between the tilt horizontal angle correction target value and the actual tilt angle detected by the tilt angle sensor becomes almost zero when approaching horizontal, a valve opening command of zero valve opening is output to the electromagnetic proportional valve. Then, the expansion and contraction of the tilt cylinder is stopped at that position, and the tilt angle is determined. Thus, the fork can be controlled to the correct tilt horizontal position regardless of the lift of the fork.

Next, a third embodiment will be described with reference to FIGS. FIG. 11 shows a working machine device of a forklift, which is an object of the present embodiment. The same components as those of the double-mast type working machine shown in FIG. 1 described in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Only different parts will be described. An inner rail 11 is provided above the outer rail 10 at a predetermined position H1 (for example, a fork 12).
A lift limit switch (hereinafter, referred to as a lift LS) 27 that is turned on when the ascent is raised above a half of the maximum ascending position. In this embodiment, the lift sensor 25 and the origin LS are unnecessary.

FIG. 12 is a block diagram of the control system. First
The same components as those of the control system block diagram shown in FIG. 2 described in the embodiment will be denoted by the same reference numerals, and description thereof will be omitted. Only different portions will be described. The controller 40 includes a tilt lever 21, a tilt automatic switch 24, a lift LS27,
And a tilt angle sensor 23, and a signal is input from each of them. The illustration of the lift lever 22 and the lift cylinder 15 is omitted. The controller 40
The storage unit and the horizontal control unit 45 are similar to the first embodiment.
And

FIG. 13 shows the tilt horizontal control means 45.
Similar to FIG. 3 described in the first embodiment, the tilt horizontal control unit 45 has a correction amount calculation unit 43 and a horizontal control unit 44. Here, the correction amount calculation unit 43 determines whether the lift is higher or lower than the predetermined position H1 based on the signal of the lift LS, and based on the determination result, determines whether the lift is higher by the changeover switch 42. Is set to a predetermined correction amount Δθ2, and a low correction value is set to a zero value or a predetermined correction amount Δθ1 that does not hinder practical use. FIG. 14 is a graph showing the relationship between the elevation area and the correction amount of the tilt horizontal angle target value. The vertical axis represents the correction amount Δθ, and the horizontal axis represents the elevation. As shown in the figure,
The lift is divided into a low region and a high region, and the correction amount in the low region is set to zero or an angle Δθ1 that does not hinder practical use, and the correction amount in the high region is set to Δθ2. Correction amount calculator 43
Calculates a correction amount based on the input lift position of the fork 12 and outputs the correction amount to the horizontal control unit 44. Note that the horizontal control unit 44 is the same as the horizontal control unit 44 described in the first embodiment, and a description thereof will be omitted.

Next, the tilt automatic horizontal control procedure will be described with reference to FIGS.
This will be described with reference to FIGS. When the operator turns on the tilt automatic switch 24 of FIG. 12 and operates the tilt lever 21, the correction amount calculating unit 43 inputs a signal from the lift LS27, and the lift of the fork 12 reaches the high lift region. It is determined whether or not. When the lift LS 27 is off, that is, when the lift of the fork 12 is in the low range, the changeover switch 42 is switched to the position A shown in FIG.
Therefore, the correction amount Δθ is set to a zero value or Δθ1. The inner rail 11 rises to a predetermined height, and the lift L
When S27 is turned on, the changeover switch 42 is switched to the position B, and the correction amount Δθ is set to Δθ2. The correction amount Δθ set to the tilt horizontal angle target value is added to calculate the tilt horizontal angle correction target value. The subsequent operation is shown in FIG.
The description is omitted because it is the same as that of the first embodiment described above.

Next, a fourth embodiment will be described with reference to FIGS. 15, 16, 17, 18, and 19. FIG. 15 shows a forklift working machine device to which the present embodiment is applied. Second
The same components as those of the triple mast type working machine of FIG. 5 described in the embodiment are denoted by the same reference numerals, and description thereof will be omitted. Only different parts will be described. Above the outer rail 10, there is provided a second lift LS27b that is turned on when the middle rail 13 is raised above a predetermined position H2. The first lift LS27a which is turned on when the first lift cylinder 15a extends beyond the predetermined position H1 is provided on the inner rail 11.
Is provided.

FIG. 16 shows another working machine device of a forklift, which is an object of the present embodiment. The same components as those of the full-flimast type working machine of FIG. 6 described in the second embodiment are denoted by the same reference numerals, and description thereof will be omitted. Only different portions will be described. Above the outer rail 10, there is provided a second lift LS27b that is turned on when the inner rail 11 is raised above a predetermined position. Further, the inner rail 11 is provided with a first lift LS27a that is turned on when the first lift cylinder 15a is extended by a predetermined amount.

FIG. 17 shows a block diagram of the control system. Second
The same components as those in the control system block diagram of FIG. 7 described in the embodiment are denoted by the same reference numerals, and description thereof will be omitted. Only different portions will be described. The controller 40 includes a tilt lever 21, a tilt automatic switch 24, a first lift LS27.
a, the second lift LS 27b, and the tilt angle sensor 23, and input respective signals. The illustration of the lift lever 22 and the lift cylinder 15 is omitted. Note that the controller 40 has a storage unit and a horizontal control unit 45 as in the first embodiment.

FIG. 18 shows the tilt horizontal control means 45.
Similar to FIG. 3 of the first embodiment, the tilt horizontal control means 45
Has a correction amount calculation unit 43 and a horizontal control unit 44. Here, the correction amount calculating unit 43 sets a predetermined large constant value when the fork 12 has a high lift, a predetermined medium constant value when the fork 12 is medium, and a zero value when the fork 12 is low. Set the correction amount. FIG. 19 is a diagram showing the relationship between the elevation area and the correction amount of the tilt horizontal angle target value. The vertical axis represents the correction amount, and the horizontal axis represents the elevation. The lift is defined as a low range from the lowest position of the fork 12 to the first lift LS27a being turned on, and the second lift L after the first lift LS27a is turned on.
A range until S27b is turned on is defined as a middle area, and a higher position is defined as a high area. Then, the tilt horizontal angle correction amount of the fork 12 in the low region is set to zero value or Δθ1, the correction amount in the middle region is set to Δθ2, and the correction amount in the high region is set to Δθ2.
θ2, which is stored in advance in the correction amount calculation unit 43. The correction amount calculation unit 43 calculates a correction amount based on the input lift position of the fork 12, and outputs the correction amount to the horizontal control unit 44. Note that the horizontal control unit 44 is the same as the horizontal control unit 44 described in the first embodiment, and a description thereof will be omitted.

Next, the tilt automatic horizontal control procedure is shown in FIGS.
This will be described with reference to FIGS. When the operator turns on the tilt automatic switch in FIG. 17 and operates the tilt lever 21, the correction calculation unit 43 inputs the detection signals from the first lift LS27a and the second lift LS27b, and the lift of the fork 12 is reduced. It is determined whether it is in the low region, the middle region, or the high region. Then, the correction amount Δθ of the tilt horizontal angle target value is selected based on the graph shown in FIG. 19, and the tilt horizontal angle target value is corrected. The subsequent operation is the same as that of the second embodiment described with reference to FIG.

According to the third and fourth embodiments, the lift LS
, The lift area of the fork is detected, and a predetermined fixed value correction amount corresponding to the lift is set in each lift area. That is, a small fixed value correction amount is set in a region where the lift is low, and a large fixed value is set in a region where the lift is high. Note that a relation graph between the elevation area and the constant value correction amount obtained in advance by calculation or an actual vehicle test is stored in the correction amount calculation unit, and a correction amount corresponding to the lift detected by the relation graph is set. In a working machine device having one lift cylinder, the lift is divided into two regions to correct two predetermined fixed values, and in a working machine device having two lift cylinders, the lift is divided into three regions. Three predetermined fixed value correction amounts are added to the tilt horizontal angle target value, respectively, to calculate a tilt horizontal angle correction target value. When the operator turns on the tilt automatic switch and operates the tilt lever in the direction in which the fork is tilted rearward, the tilt horizontal angle approaches the tilt horizontal angle correction target value, that is, approaches the horizontal level. When approaching the horizontal, when the deviation value between the tilt horizontal angle correction target value and the actual tilt angle detected by the tilt angle sensor becomes substantially zero value, the expansion and contraction of the tilt cylinder stops at that position,
The tilt angle is determined. Thus, it is possible to obtain a forklift automatic tilt and level control device for controlling the fork to a correct tilt horizontal position regardless of the lift of the fork. In addition, a tilt automatic level control device that uses a height LS instead of an encoder to detect the height of the fork is inexpensive, and can perform tilt automatic level control within a range that does not hinder practical use. can get.

In the third and fourth embodiments, the relationship between the correction amount and the lift is adjusted by a variable volume control in order to cope with a change in the tilt amount caused by the sloping condition of the road surface to be worked or the dent of the tire. Alternatively, the configuration may be changed.

As described above, according to the present invention, the relational data between the lift and the correction amount obtained in advance by the calculation or the actual vehicle test is stored in the controller, and the stored correction data is used when the lift is low. , And a large correction amount is set when it is high. Each of the set correction amounts is added to the tilt horizontal angle target value to obtain a tilt horizontal angle correction target value, and the tilt angle is controlled so that the actual tilt angle approaches the tilt horizontal angle correction target value. This allows
It is possible to obtain a tilt automatic horizontal control device of a forklift that controls the fork to a correct tilt horizontal position regardless of the lift of the fork. Furthermore, when unloading a load placed on a rack, etc., the fork is set horizontally, so that it can be efficiently inserted into the fork insertion port of the pallet even at a high lift position without interference between the fork and the pallet. Thus, it is possible to obtain a forklift tilt automatic horizontal control device with good workability without load collapse.

[Brief description of the drawings]

FIG. 1 is a schematic view of a working machine device according to a first embodiment of the present invention.

FIG. 2 is a control system block diagram of a first embodiment of the present invention.

FIG. 3 is an explanatory diagram of the operation of the tilt horizontal control means according to the first embodiment of the present invention.

FIG. 4 is a graph showing a relationship between a lift position and a correction amount stored in a correction amount calculation unit according to the first embodiment of the present invention.

FIG. 5 is a schematic diagram of a first working machine device according to a second embodiment of the present invention.

FIG. 6 is a schematic diagram of a second working machine device according to the second embodiment of the present invention.

FIG. 7 is a tilt control system block diagram according to a second embodiment of the present invention.

FIG. 8 is an explanatory diagram of the operation of the tilt horizontal control means according to the second embodiment of the present invention.

FIG. 9 is a graph illustrating a relationship between a first-stage elevation position and a correction amount stored in a correction amount calculation unit according to a second embodiment of the present invention.

FIG. 10 is a graph illustrating a relationship between a second-stage elevation position and a correction amount stored in a correction amount calculation unit according to the second embodiment of the present invention.

FIG. 11 is a schematic view of a working machine device according to a third embodiment of the present invention.

FIG. 12 is a block diagram of a tilt control system according to a third embodiment of the present invention.

FIG. 13 is an explanatory diagram of the operation of the tilt horizontal control means according to the third embodiment of the present invention.

FIG. 14 is a graph showing a relationship between a lift area and a correction amount stored in a correction amount calculation unit according to a third embodiment of the present invention.

FIG. 15 is a schematic diagram of a first working machine device according to a fourth embodiment of the present invention.

FIG. 16 is a schematic view of a second working machine device according to a fourth embodiment of the present invention.

FIG. 17 is a block diagram of a tilt control system according to a fourth embodiment of the present invention.

FIG. 18 is an explanatory diagram of a tilt horizontal control unit according to a fourth embodiment of the present invention.

FIG. 19 is a graph showing a relationship between a lift area and a correction amount stored in a correction amount calculation unit according to a fourth embodiment of the present invention.

FIG. 20 is a side view of the forklift.

FIG. 21 is a configuration diagram of a forklift rail and a fork.

FIG. 22 is an explanatory view showing a state where the forklift of the forklift is lifted.

[Explanation of symbols]

5 Working machine device, 10 Outer rail, 11 Inner rail, 12 Fork, 13 Middle rail, 14 Tilt cylinder, 21 Tilt lever, 23 Tilt angle sensor, 24 Tilt automatic switch, 25 Lifting height Sensors,
25a: first lift sensor, 25b: second lift sensor, 2
6 ... Origin LS, 27 ... Height LS, 27a ... First lift L
S, 27b ... second lifting LS, 30 ... electric motor, 31 ...
Hydraulic pump, 32: electromagnetic proportional valve, 37: electric motor drive device, 40: controller, 41: drive unit, 43: correction amount calculation unit, 44: horizontal control unit.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Norihiko Eda 110 Yokokura Nitta, Koyama City, Tochigi Prefecture Komatsu Forklift Co., Ltd. Tochigi Plant F-term (reference) 3F333 AA02 AB14 BA02 BB02 BD02 BE02 FA17 FB10 FD03 FD08 FE09

Claims (1)

[Claims] 1. A tilt angle sensor for detecting a tilt angle value of a fork of a forklift, an electromagnetic proportional valve for expanding and contracting a tilt cylinder for controlling a tilt angle, and a tilt horizontal angle previously stored in a storage unit or set by an operator. A forklift comprising: a tilt horizontal control unit having a horizontal control unit that controls a tilt angle by outputting a command signal calculated based on a deviation value between a target value and a tilt angle value detected by a tilt angle sensor to an electromagnetic proportional valve. In the automatic level control device according to the above, a lift sensor for detecting a lift of the fork is additionally provided, and the tilt horizontal control means calculates a correction amount of the tilt angle according to the lift detected by the lift sensor. The horizontal control unit of the tilt horizontal control means stores a tilt horizontal angle correction target value required for calculating the electromagnetic proportional valve command signal in a storage unit in advance. Automatic horizontal control device for a forklift characterized in that 憶 is allowed or operator determined by adding the correction amount calculated by the correction amount calculation unit to tilt the horizontal angle target value set.