JPH11268900A - Lift truck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the steering operation from a lifter by driving a power steering in response to the output of a comparator generating an angle difference signal corresponding to the difference between the steering angle signal of a joystick lever and the output of the steering angle sensor of a steering wheel. SOLUTION: Gears 15, 16 are meshed with a gear 14 fixed to the outer periphery of the support bracket 13 of a drive wheel 11 driven by a traveling motor 12. A potentiometer 17 detects the revolving speed of the gear 15 to measure the steering angle of the drive wheel 11. The gears 16, 14 are rotated by the operation of a worker on a handle 23 via sprockets 22, 20, a chain 21, a torque sensor 19 and a power steering device 18, and the drive wheel 11 is rotated around the axis 24 by the desired angle. The lateral inclination of an operation lever 30 is detected by a potentiometer 32 to set the steering angle of the drive wheel 11. A comparator compares the signals from the potentiometers 17, 32 and outputs a signal corresponding to the difference to drive a power steering motor 27.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lift truck typified by a forklift and the like, and more particularly to a lift having a driving operation device for operating a vehicle body in a driver's seat of a vehicle body and a lifter provided on the vehicle body. About the truck.

[0002]

2. Description of the Related Art In order to facilitate picking work from a warehouse shelf, a lift truck is provided with a separate from a normal driver's seat.
Some lifters are provided with an auxiliary device for operating the vehicle body on a lifter that carries a load and moves up and down. By operating this device, the operator performs the picking operation on the lifter and controls the traveling of the vehicle body directly from the lifter.

[0003]

In the lift truck of the type described above, the lifter-side driving operation device is provided for supplementary use only in picking work and the like, and its installation space is limited. Therefore, it is difficult to provide a large-sized device such as a vehicle body driver's seat.

[0004] For this reason, conventionally, only a device having a very simple configuration is provided, and the steering operation from the lifter is extremely difficult and requires skill. The present invention has been proposed in view of such circumstances, and an object of the present invention is to provide a lift truck that can be installed in a small space and has good driving operability.

[0005]

Means for Solving the Problems In order to solve this problem, a driver's seat of a vehicle body and a lifter provided on the vehicle body each have a driving operation device for operating the traveling of the vehicle body, and
A steering angle input means of the vehicle-side driving operation device and a steering wheel are mechanically connected, a torque sensor for detecting a steering force by the input means, and a power for assisting the steering force in accordance with an output of the sensor A lift truck provided with a steering motor, wherein the lifter-side driving operation device is provided with steering angle input means including a joystick lever that emits a steering angle signal corresponding to the inclination angle, and the actual steering angle of the steering wheel is determined. A steering angle sensor for detecting, a comparator for generating an angle difference signal corresponding to a difference between a steering angle signal of the lever and an output of the steering angle sensor, and a motor for driving the motor in accordance with an output of the comparator. And a controller for matching the steering angle of the vehicle with the steering angle signal.

In the present invention, first, the steering angle input means of the lifter-side driving operation device is connected to a known joystick lever, for example, a steering angle signal corresponding to an inclination angle as disclosed in Japanese Patent Application Laid-Open No. H2-220972. A lever-shaped device that emits Therefore, it requires less installation space than a normal circular handle, and is suitable for installation on a lifter.

A steering motor is driven in accordance with the difference between the steering angle signal from the lever and the actual steering angle, so that the actual steering angle matches the steering angle signal from the lever. Therefore, since the inclination angle of the lever always coincides with the steering angle of the vehicle body, the traveling operation from the lifter becomes easy.

Further, since the power steering motor provided to assist the steering force from the vehicle body is used as the steering motor, the motor can be effectively used in each of the steering operations from the vehicle body and the lifter. Can be used.

In the present invention, it is preferable that the steering operation from the vehicle body side and the steering operation from the lifter side are alternately switched and operated via appropriate switching means.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to examples.

[0011]

1 and 2 show a lift truck according to the present invention. This lift truck is based on a reach-type forklift driven by a battery, and has a lifter to which an auxiliary driving operation device is added.

FIG. 1 shows the entire side surface of a lift truck, and a driver's seat 2 and a main operation device 3 for driving operation of the vehicle body are provided at a rear portion of the vehicle body 1. A movable mast 4 is provided upright at the front of the vehicle body, and a lifter 6 having a fork 5 is provided so as to be able to move up and down along the mast 4. P is a pallet mounted on the fork 5, and 7 is a head guard for protecting the operator on the driver's seat 3 from falling objects.

When a worker M picks up a required load from a shelf in a warehouse, the worker M stands on the pallet P as shown in the figure and moves up to a target shelf together with the lifter 6.
Reference numeral 8 denotes a guard bar for preventing the worker from dropping from the lifter at this time, and is provided on the lifter 6 so as to be pivotable.

FIG. 2 shows a front view of the lifter 6, and an auxiliary driving operation device 9 on the upper portion of the lifter 6 for the worker M on the pallet P to operate the vehicle body 1 in the rear direction of the vehicle body 1. Is provided. Reference numeral 10 denotes a lifting / lowering operation device for the lifter 6 disposed beside the auxiliary operation operation device 9.

FIG. 3 shows a steering device of the present lift truck. Reference numeral 11 denotes drive wheels provided on the vehicle body of the truck so as to be steerable, and is rotationally driven by a traveling motor 12. Gears 14 are provided on the outer periphery of the bracket 13 for indicating the drive wheels 11.
Are fixed, and another gear 15, 16 is meshed with the gear 14. The shaft of one gear 15 is a potentiometer 17
The potentiometer 17 measures the steering angle of the drive wheel 11 by detecting the rotation speed of the gear 15. The shaft of the other gear 16 is connected to a sprocket 20 via a power steering device 18 and a torque sensor 19.
Fixed to The sprocket 20 is operatively connected to another sprocket 22 through an endless chain 21. The axis of the other sprocket 22 has a circular handle 23 as a steering input device provided in the main operation operation device 3 described above. It is fixed to.

Therefore, when the operator turns the handle 23, the gear 16 rotates through the sprockets 20, 22 and the chain 21, and the gear 14 meshing with the gear 16 rotates, so that the driving wheel 11 rotates around the shaft 24. At a desired angle.

The torque sensor 19 includes a sprocket 20
This is a sensor for detecting a relative twist between the shaft 25 on the gear side and the shaft 26 on the gear 16 side, and drives the power steering motor 27 according to the amount of the twist. The motor 27 is provided in the power steering device 18 together with the speed reduction mechanism, and applies an assist torque to the shaft 26 to reduce the turning effort of the handle 23.

Reference numeral 30 denotes an operation lever provided on the auxiliary driving operation device 9 described above. The lever 30 is a well-known joystick lever, is provided so as to be tiltable in both front and rear directions and left and right directions of the vehicle body, and is urged by a spring 31 to return to an upright posture.

The operating lever 30 instructs forward when the vehicle is inclined forward, and backward when the vehicle is inclined backward, and the traveling speed is set according to the angle of inclination. The angle of the inclination in the left-right direction is detected by the potentiometer 32, and the steering angle of the drive wheel 11 is set accordingly.

FIG. 4 is an electric circuit diagram for controlling the steering angle of the drive wheel 11 by the handle 23 and the operation lever 30. Reference numeral 33 denotes a key switch provided on the main driving operation device 3 of the vehicle body together with the handle 23, and reference numeral 34 denotes a key switch provided on the auxiliary driving operation device 9 of the lift together with the lever device 30. When the key switches 32 and 33 are turned on or off, another changeover switch 34 is switched. When the first key switch 33 on the main operation operation device 3 side is turned on, an output signal from the torque sensor 19 is transmitted to the controller. When the second key switch 34 on the auxiliary driving operation device 9 side is turned on, the output signal of the comparator 36 is sent to the controller 35.

The comparator 36 is provided with a potentiometer 17,
The controller 35 converts these signals from each other and outputs a signal corresponding to the difference. The controller 35 converts these signals into drive signals and outputs them to drive the power steering motor 27. Drive wheel 11
Is steered, and as a result, a steering angle corresponding to the operation angle of the steering wheel or the operation lever 30 is realized.

[0022]

As described above, according to the present invention, since the steering input device on the lifter is a joystick lever, the installation space can be reduced, and the instruction of the steering angle by the lever can be performed by operating the steering wheel of the vehicle body driver's seat. The steering is controlled by driving a power steering motor for assisting the steering, so that the motor can be used effectively, and the inclination angle of the lever always coincides with the steering angle of the wheel. There is an advantage that the steering control can be easily performed even on a lifter in which is not visible.

[Brief description of the drawings]

FIG. 1 is a side view of a lift truck according to the present invention.

FIG. 2 is a front view showing a lifter.

FIG. 3 is a schematic diagram showing a steering mechanism according to the present invention.

FIG. 4 is an electric circuit diagram according to the present invention.

[Explanation of symbols]

 1: body 3: main driving operation device 6: lifter 9: auxiliary driving operation device 11: driving wheel (steering wheel) 17: potentiometer (steering angle sensor) 19: torque sensor 23: steering wheel (steering angle input means) 27: Power steering motor 30: Operation lever (joystick lever) 32: Potentiometer 35: Controller 36: Comparator

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B66F 9/06 B66F 9/06 J // B62D 113: 00 119: 00

Claims (1)

[Claims] An operation device for operating the traveling of a vehicle body is provided in a driver seat of the vehicle body and a lifter provided on the vehicle body, and a steering angle input means and a steering wheel of the vehicle-side operation operation device are provided. And a power steering motor that assists the steering force according to the output of the torque sensor, the lift truck being mechanically connected to the lifter side. A steering angle input means comprising a joystick lever for issuing a steering angle signal corresponding to the tilt angle is provided in the operating device, a steering angle sensor for detecting an actual steering angle of the steering wheel, a steering angle signal of the lever, and A comparator for generating an angle difference signal corresponding to a difference from an output of the steering angle sensor; and driving the motor in accordance with the output of the comparator to calculate the actual steering angle. Lift truck, characterized in that a controller to match the signal.