JP2000191295A - Tilting speed control device of fork lift truck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To greatly reduce shift, etc., of the cargo at the forward tilting end or backward tilting end when a mast is tilted. SOLUTION: A mast is provided in the front part of a vehicle body in such a way as tiltable operated by a tilt cylinder 2, and a fork is installed as capable of rising and falling along the mast, and tilting of the mast by the cylinder 2 is made in compliance with the operating amount of a tilting lever, and in this fork lift truck, a specified angle range fore and aft by reference to the mast vertical positioning in tilting motion is made a neutral region while the range outside the neutral is made a front and a rear region, and a control part 10 control the cylinder 2 so that the mast tilting speed is generated on the basis of a map for high speed in the neutral region and the tilting speed is on the basis of a map for low speed in the front and rear regions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tilt speed control device for a forklift truck, in which a tilt speed of a mast is switched between a high speed and a low speed.

[0002]

2. Description of the Related Art Conventionally, a forklift truck is provided with a pair of left and right masts which can be tilted by a tilt cylinder at the front of a vehicle body, and left and right forks which can be moved up and down by a lift cylinder along the masts. Had been. In such a forklift truck, when the tilt cylinder is tilted by the tilt cylinder, the tilt cylinder is operated in accordance with the operation of a tilt lever provided in the cab, thereby tilting the mast.

[0003]

In the conventional tilting of the mast, the tilt cylinder operates in response to the operation of the tilt lever, and the tilting of the mast is performed. The speed is always a predetermined value according to the operation of the tilt lever. If the tilting speed is high at the forward tilting end or the rearward tilting end of the mast, load collapse may occur, and the operation of the tilt lever at the forward tilting or the rearward tilting end is performed at the tilting speed. The operator has been required to perform a fine operation on the tilt lever so as not to be quick. For this reason,
The mental burden at the time of work is large, and a worker with little experience may have a decrease in work efficiency. An object of the present invention is to solve this problem.

[0004]

According to a first aspect of the present invention, there is provided a mast provided at a front portion of a vehicle body which can be tilted by a tilt cylinder, a fork which can be moved up and down along the mast, and a mast provided by a tilt cylinder. In a forklift truck in which the tilting of the mast is operated in accordance with the amount of operation of the tilt lever, a neutral region is defined as a neutral region within a predetermined angle range before and after the mast vertical position with respect to the mast vertical position. As an area,
Forklift truck having a control unit that controls a tilt cylinder so that the mast tilting speed based on the high-speed map is used in the neutral region and the mast tilting speed based on the low-speed map is used in the front and rear regions. Is a tilt speed control device.

According to a second aspect of the present invention, there is provided a forklift truck according to the first aspect, wherein the forklift truck switches based on a switching pattern in which the mast tilting speed is gradually switched when switching between the neutral region and the front and rear regions. This is a tilt speed control device.

A second aspect of the present invention is a tilt speed control device for a forklift truck in which a predetermined angle range before and after the neutral region can be changed to a desired range by a volume or the like in the control unit according to the first or second aspect.

[0007]

According to the first aspect of the present invention, in the front and rear regions of the mast tilting, that is, the forward tilting end portion and the rearward tilting end portion, the tilting speed becomes a speed based on the low speed map, that is, a low speed. The occurrence of collapse etc. can be greatly reduced,
In addition to reducing the mental burden on the worker at the time of work, even a beginner with little experience can perform work easily and safely, thereby suppressing a decrease in work efficiency.

According to the second aspect of the invention, the mast tilting speed is gradually switched when switching between the neutral region and the front / rear region, thereby preventing a shock or the like at the moment of switching.

According to the third aspect, the predetermined angle range before and after the neutral region can be changed to a desired range by a volume or the like, and this is changed according to the type of luggage, the work content thereof, or the preference of the operator. By doing so, it is always possible to work in an optimal state.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described. As shown in FIG. 1, the forklift truck is provided with a pair of left and right masts 3 which can be tilted by a tilt cylinder 2 at the front of the vehicle body 1 as in the prior art.
A left and right fork 5 which can be moved up and down by a lift cylinder 4 along the mast 3 is provided.

The operator's cab 6 of the vehicle body 1 is provided with a tilt lever 7, and the tilt cylinder 2 operates in response to the operation of the tilt lever 7 to tilt the mast 3. Is provided with a lever detector 8 for detecting the operation direction and the operation amount of the tilt lever 7, and the lever detector 8 is a potentiometer.

Further, in the forklift truck having such a configuration, a mast tilt angle detecting section 9 for detecting a tilt angle in tilting of the mast 3 is provided. The mast tilt angle detecting section 9 is provided in the tilt cylinder 2 and the tilt cylinder is provided. A potentiometer that detects the stroke amount of 2,
The tilt angle of the mast is obtained from the stroke amount of the tilt cylinder 2.

A control unit 10 is provided inside the vehicle body 1,
The control unit 10 sets a neutral area within a predetermined angle range between the predetermined angle toward the forward tilt side and the predetermined angle toward the rear tilt side based on the mast vertical position in the tilting of the mast 3,
A range other than the neutral region is defined as a front and rear region. In the neutral region, the tilting speed of the mast 3 based on the high speed map H is set in accordance with the operation amount of the tilt lever 7, and in the front and rear region, the tilt lever 7 is moved. The tilt cylinder 2 is controlled so that the mast 3 tilts based on the low speed map L in accordance with the operation amount.

As shown in FIG. 2, the control section 10 has an input section 11 for directly inputting each data from a lever detection section 8 and a mast tilt angle detection section 9 and an operation for receiving each data from the input section 11. ROM 12 and RAM 13 for processing
And a microcomputer 15 comprising a CPU 14 and this microcomputer 1
And an output unit 16 for outputting a command value from the control unit 5 to the outside. The command value from the output unit 16 is supplied to a proportional solenoid valve 17 which supplies pressure oil to the tilt cylinder 2 and controls the operation of the tilt cylinder 2. By controlling the valve opening of the proportional solenoid valve 17 with this valve opening value,
The tilt cylinder 2 is controlled.

Next, the control of the tilt cylinder 2 by the control unit 10 will be specifically described. In the microcomputer 15, a high-speed map H indicating the high-speed tilt of the mast 3 according to the operation of the tilt lever 7 in advance, and a low-speed map L indicating the low-speed tilt of the mast 3 according to the operation of the tilt lever 7
As shown in FIG. 3, the high-speed map H and the low-speed map L have the same high-speed map H as the command value to be output even if the operation amount of the tilt lever 7 is the same, as shown in FIG. The value is set to be low so that the tilting speed of the mast 3 is divided into a high speed and a low speed. In the tilting speed of the mast 3 using the high-speed map H and the low-speed map L, the high-speed tilting is set to be substantially the same as the conventional normal speed, and the low-speed tilting is set to the speed. Is set to be significantly lower. The setting of this low-speed tilting is such that the load on the fork 5 does not collapse due to experiments or the like in advance. The setting of the high-speed tilt and the setting of the low-speed tilt are not limited to those described above, and the settings can be arbitrarily changed.

On the other hand, a neutral range is set within a predetermined angle range before and after the vertical position of the mast 3 when the mast 3 is tilted, and a range other than the neutral region is set as a front and rear area. The setting of the neutral region is performed, for example, by mounting a volume 18 or the like in the operator's cab 6 of the vehicle body 1.
8 and the like allow the operator to arbitrarily change the neutral angle range of the front and rear predetermined angle range.

In the neutral region thus set, the mast 3 tilting speed based on the high speed map H is used, and in the front and rear regions, the mast 3 tilting speed based on the low speed map L is used. As a result, in the neutral region and the front and rear regions in the tilting of the mast 3, the neutral region has a high speed and the front and rear regions have a low speed even when the tilt lever 7 has the same operation amount as the tilt lever 7.

In the control unit 10, when switching between the neutral region and the front / rear region, ie, switching from the neutral region to the front / rear region or from the front / rear region to the neutral region,
So that the tilting speed is gradually switched. This calculates the speed difference between the neutral region and the front and rear regions at the time of switching, and sets a switching pattern in which the speed is gradually switched by making the speed difference gradually smaller, based on this switching pattern. Thus, the tilting speed of the mast 3 is gradually switched to prevent occurrence of a shock or the like at the moment of switching.

Further description will be made with reference to the flowchart shown in FIG. First, after initialization is performed, the operation amount T of the tilt lever 7 is input from the lever detection unit 8. Also,
The tilt angle R of the mast 3 is input from the mast tilt angle detection unit 9. Based on the input tilt angle R of the mast 3, it is determined whether the tilt of the mast 3 is in the neutral region or the front and rear region. When the tilt of the mast 3 is in the neutral region, a command value for the tilt speed of the mast 3 based on the high-speed map H is calculated according to the input operation amount T of the tilt lever 7. When the tilt of the mast 3 is in the front and rear region, a command value for the tilt speed of the mast 3 based on the low speed map L is calculated according to the input operation amount T of the tilt lever 7. Then, these calculated command values are output. When the command value is output, the state returns to the state after the initialization, and the operation amount T of the tilt lever 7 is input again from the lever detection unit 8, and this operation is repeated.

In this manner, in the front and rear regions of the mast tilting, that is, the front tilting end portion and the rear tilting end portion, the tilting speed becomes a speed based on the low speed map, that is, a low speed. It is possible to greatly reduce the mental burden on the worker at the time of work, and it is possible to easily and safely perform work even for an inexperienced beginner, thereby suppressing a decrease in work efficiency. In addition, when the mast is tilted over a wide range by setting the mast to a low speed only in the front and rear areas where the collapse of the load is likely to occur, and by increasing the speed of the mast to a high speed in the neutral region where the load is not likely to collapse. Can be prevented from significantly decreasing.

Further, the operator can arbitrarily change the neutral angle range, which is the neutral area, by using the volume 18 or the like. The range of the predetermined angle before and after the neutral region can be changed according to the condition, and the work can always be performed in an optimal state.

[0022]

According to the present invention, in the front and rear regions of the mast tilting, that is, the forward and backward tilting ends, the tilting speed becomes a speed based on the low speed map, that is, a low speed, so that the occurrence of load collapse and the like is greatly reduced. In addition to reducing the mental burden on the worker at the time of work, even a beginner with little experience can perform work easily and safely, thereby suppressing a decrease in work efficiency.

By changing the tilting speed of the mast gradually at the time of switching between the neutral region and the front and rear region, it is possible to prevent the occurrence of a shock or the like at the moment of switching, thereby improving the safety of work.

A predetermined angle range before and after the neutral area can be changed to a desired range by a volume or the like, and the angle can be changed in accordance with the type of the baggage, the work content thereof, or the preference of the worker, so that the optimum condition is always maintained. Work can be performed, and workability can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a forklift truck according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a configuration of a control unit according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a high-speed map H and a low-speed map L according to the embodiment of the present invention.

FIG. 4 is a flowchart showing control contents according to the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Body, 2 ... Tilt cylinder, 3 ... Mast, 4 ... Lift cylinder, 5 ... Fork, 6 ... Operating room, 7 ... Tilt lever, 8 ... Lever detection part, 9 ... Mast tilt angle detection part, 1
0: control unit, 11: input unit, 12: ROM, 13: RA
M, 14 CPU, 15 microcomputer, 16 output unit, 1
7 ... proportional solenoid valve, 18 ... volume.

Claims (3)

[Claims] 1. A mast 3 which can be tilted by a tilt cylinder 2 at a front portion of a vehicle body 1 and a fork 5 which can be moved up and down along the mast 3 and a tilt of the mast 3 by the tilt cylinder 2 is provided. In a forklift truck that operates in accordance with the lever operation amount of the tilt lever 7, a neutral region is defined as a neutral range within a predetermined angle range before and after the mast vertical position when the mast 3 is tilted, and a range other than the neutral region is defined as a front and rear region. In the neutral region, the tilting speed of the mast 3 based on the high-speed map is used, and in the front and rear regions, the mast 3 based on the low-speed map is used.
1. A tilt speed control device for a forklift truck, comprising: a control unit 10 that controls the tilt cylinder 2 so that the tilt speed is set to a predetermined tilt speed. 2. The control unit according to claim 1, wherein the switching is performed based on a switching pattern in which the tilting speed of the mast is gradually switched when switching between the neutral region and the front and rear region. Speed control device for forklift trucks. 3. The tilt speed control device for a forklift truck according to claim 1, wherein the control unit 10 can change a predetermined angle range before and after the neutral region to a desired range by using a volume 18 or the like.