JPH0124719B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a forklift or the like that automatically performs work such as cargo handling based on a work command signal output from a speed command circuit composed of, for example, a microcomputer or a switching circuit. This invention relates to a work speed control device for industrial vehicles.

Generally, in a forklift equipped with a working speed control circuit using a microcomputer, etc., the fork is moved to a target height by manually operating the lift cylinder in advance, and then the address designation key is operated to control the working speed. This is stored in the control circuit, and when the user presses the address designation key and then operates the switch for raising and lowering the fork, the fork automatically moves to the memorized target height and stops. In the above-mentioned battery-type forklift, in which two hydraulic motors are driven by two electric motors to carry out travel and cargo handling operations separately, when carrying out cargo handling work while the forklift is moving, the cargo handling hydraulic motor is driven by two electric motors. Even if the rotation speed is increased to the required number, the traveling hydraulic motor is not affected, so the forklift does not run out of control and there is no problem.

However, forklifts use the same engine to extract power for driving and cargo handling.
When the forklift is automatically raised and lowered to the target height and stopped based on the signal from the work speed control circuit while traveling at low speed, when the engine changes from low speed rotation to high speed required for cargo handling, the forklift will stop traveling at low speed. There was a flaw in the vehicle's ability to suddenly reach high speeds and run out of control, causing cargo to fall and accidents resulting in personal injury. Also, when the forklift's clutch pedal is depressed or the gear shift lever is in the neutral position, that is, when power transmission between the drive wheels and the engine is cut off, cargo handling is performed based on the signal from the work speed control circuit. During work, if the clutch pedal is released and the gear shift lever is moved to a position other than neutral, the vehicle will suddenly start, resulting in the same defect as described above.

An object of the present invention is to prevent work from being carried out using signals from a work speed command circuit when running at low speeds, prevent the vehicle from running out of control, eliminate falling cargo and personal accidents, and improve safety in industrial vehicles. An object of the present invention is to provide a working speed control device.

Hereinafter, an embodiment in which the present invention is embodied in an engine-type forklift will be explained with reference to FIGS. 1 and 2. FIG. clutch 2
A transmission 3 is installed through the transmission 3, and an output rotation shaft 4 of the transmission 3 is connected to a differential gear device 5, and the rotation of the rotation shaft 4 rotates a pair of left and right running wheels 6, so that the forklift can travel. It is beginning to be practiced.

A hydraulic pump 8 is attached to the engine 1 via a power take-off device 7, and this pump introduces oil from a tank 9 and sends it under pressure to a control valve 10. Pressure oil can be supplied to the tilt cylinder 12 for tilting.

Furthermore, the throttle lever 1 of the engine 1
3 is connected to a manual transmission mechanism M whose rotational speed can be adjusted steplessly through normal manual operations. To this transmission mechanism M, a traveling detection means A detects whether or not the forklift is in a traveling state and outputs a traveling power disconnection signal or a traveling power contact signal, and outputs a cargo handling work speed conversion command. The rotational speed of the engine 1 is determined based on the cargo handling speed command signal output from the discrimination circuit C, and the discrimination circuit C that discriminates the signals output from the detection means A and the command circuit B. A working speed control device according to the present invention is connected to the automatic transmission mechanism D, which automatically adjusts the speed.

First, the manual transmission mechanism M and the automatic transmission mechanism D will be explained with reference to FIG.
A wire 16 is connected between one end of the arm 14 and the throttle lever 13.
A return spring 17 is further wound around the support shaft 15 for biasing the throttle lever 13 to the idling position. The operating arm 14 is rotated by an accelerator pedal 18 disposed on the floor of the driver's seat of the forklift and a rod 19 connected to the pedal, so that normal manual gear shifting can be performed.

On the other hand, electromagnetic solenoids MS ₁ and MS ₂ are installed in parallel to each other at a fixed position on the frame of the forklift for switching the cargo handling speed between low speed and high speed based on the cargo handling speed command signal from the discrimination circuit C. The stroke of the rod 21 of the electromagnetic solenoid MS ₂ is set longer than the stroke of the rod 20 of the electromagnetic solenoid MS ₁ , and in the vicinity of their tips there are support shafts 24 and 25 with operating arms 22 and 23 provided at fixed positions, respectively. rotatably supported by
Each actuating arm 22, 23 and the rod 20, 21
Links 26 and 27 are connected between them by pins, respectively. A rod 28 is connected to the actuating arms 22 and 23, and the upper end of the rod 28 is slidably engaged along a long hole 22a formed in the actuating arm 22.

Further, an actuation arm 29 is fixed on the support shaft 25 and rotates integrally with the actuation arm 23.
The tip of the arm 29 and the manual transmission mechanism M
A wire 30 is connected to the side operating arm 14, and a connecting pin 30a at the tip of the wire 30 is engaged so as to be relatively movable along a long hole 14a provided in the operating arm 14. The elongated hole 14a and the connecting pin 30a constitute operation permitting means for allowing the depression operation of the accelerator pedal 18, that is, the operation of the manual transmission mechanism M to be performed independently of the automatic transmission mechanism D.

Furthermore, the operating arm 2 is disposed on the support shaft 25.
2, 23, 29 to a predetermined position, that is, a position corresponding to the idling position of the throttle lever 13.
A stopper 32 is provided near the support shaft 24 of the actuating arm 22 in order to hold the actuating arm 22.

Therefore, when the manual transmission mechanism M and the automatic transmission mechanism D are in an idling state as shown in FIG. 2, the electromagnetic solenoid MS ₁ is activated in response to a low-speed cargo handling command, and the rod 20 moves in the direction of the arrow in the figure. , the actuating arm 22 is rotated clockwise around the support shaft 24 via the link 26, and at the same time, the actuating arms 23 and 29 are returned through the rod 28 around the support shaft 25. The spring 31 is rotated in the same direction against the elastic force of the spring 31, whereby the actuating arm 14 is rotated counterclockwise about the support shaft 15 against the elastic force of the return spring 17 via the wire 30. The throttle lever 13 is switched to the low speed position. Note that when the accelerator pedal 18 is pressed in this low speed state, the actuation arm 14 rotates, but since the tip of the wire 30 is engaged with the elongated hole 14a of the arm 14, the wire 30 is maintained in the low speed state. Therefore, high-speed cargo handling work can be performed by manual operation independently of the automatic transmission mechanism D.

In addition, in the low-speed cargo handling state described above, when the electromagnetic solenoid MS ₂ is activated in response to a high-speed cargo handling command from the discrimination circuit C and the rod 21 is further moved in the direction of the arrow in FIG. The actuating arm 23 is rotated, and the wire 30 causes the actuating arm 14 to be rotated, so that the throttle lever 13 is switched to the high speed position. Note that when this operation is performed, the rod 28 also moves upward, and its upper end is connected to the elongated hole 22a of the operating arm 22.
, the actuating arm 22 remains stationary.

Next, a series of detection means A, command circuit B, and discrimination circuit C that output a low-speed or high-speed cargo handling command to the automatic transmission mechanism D will be explained. The clutch switch 34, which is closed when the power to the running wheels 6 is cut off by the depressing action, and the shift lever (not shown) of the transmission 3 are returned to the neutral position, and the operation to the running wheels 6 is stopped. A gear shift lever switch 35, which is closed when in the disconnected state, is connected in parallel. In this embodiment, the switches 34 and 35 constitute a detecting means A that detects whether the power is connected or disconnected between the engine 1 and the running wheels 6, and outputs an operating voltage as a running power disconnection signal only when the power is disconnected. are doing.

The cargo handling speed command circuit B connected to the operating power source 33 is configured by a microcomputer, and stores the lift height or inclination angle of the fork, and adjusts the fork to the target height or target inclination position based on the memory. A cargo handling command to automatically move the cargo handling work command is output, and a speed conversion command to increase the rotation speed of the engine 1 to a required rotation is output simultaneously with this cargo handling work command. The low speed and high speed working speed commands output from the command circuit B are input to relays R ₁ and R ₂ constituting the discrimination circuit C, respectively.

Normally open contacts R _{1 -a} , R ₂ -a of the relays R ₁ and R ₂
The input terminals of the clutch switch 3 are respectively connected to the clutch switch 3.
4 and the output terminal of the gear shift lever switch 35, and the output terminals of the contacts R ₁ -a and R ₂ -a are
The voltage from the operating power supply 33 is connected to _{the electromagnetic solenoids MS 1 and} MS _{2 .}
is applied so that

Therefore, as shown in FIG. 2, the throttle lever 13 of the engine 1 is now in the idling position.
When the clutch pedal is depressed or the gear shift lever is returned to the neutral position, engine 1
When the power is cut off from the forklift to the running wheels 6, the forklift is stopped (it may be running due to inertia), and the clutch switch 34 or the gear lever switch 35 is closed, the working speed command is When a low speed work command is issued from circuit B, relay R ₁ is activated and its normally open contact R ₁ -a
is closed, the electromagnetic solenoid MS ₁ is energized, the engine 1 changes from an idling state to a low-speed state, and low-speed cargo handling work is performed.

Also, in this low-speed cargo handling state, when a high-speed work command is issued from command circuit B, relay R ₂
is activated, its normally open contact R ₂ -a is closed, and the electromagnetic solenoid MS ₂ is energized, so that the engine 1 is placed in a high speed state and high speed cargo handling work is performed.

If the clutch pedal is accidentally returned and the gear shift lever is switched from the neutral position to the forward position during the above-mentioned high-speed cargo handling operation, both the clutch switch 34 and the gear lever switch 35 are opened, so that the electromagnetic solenoid MS ₁ , MS ₂ are demagnetized, and therefore the throttle lever 13 is immediately returned to the idling state, making it possible to prevent the forklift from running out of control.

Furthermore, even if a low-speed or high-speed work command is erroneously output from command circuit B and relay R ₁ or R ₂ is activated during forced travel of the forklift whose running wheels 6 are driven by the power of engine 1. , the clutch switch 34 and the gear shift lever switch 35 are open, so the electromagnetic solenoids MS ₁ and MS ₂ are not energized, thereby preventing runaway during running.

Another embodiment of the invention will now be described with reference to FIG.

This embodiment is similar to the actuating arm 29 of the previous embodiment.
A rotary shaft 38 of a motor 37 is connected to the spindle 25 to which the motor 37 is attached via an electromagnetic clutch 36, and a variable resistor (potentiometer) is installed at the other end of the rotary shaft 38 to detect its rotation angle. Equipped with an angle detector consisting of 39 points. Then, when the engine 1 and the running wheels 6 are in a power-off state, when a low-speed or high-speed work command is output from the command circuit B, the electromagnetic clutch 36 is activated to connect the support shaft 25 and the rotating shaft 38, and The motor 37 is started and the spindle 2
5 and the actuating arm 29 are rotated, and when the variable resistor 39 reaches the low speed or high speed setting value, the motor 3
7 is stopped and the throttle lever 13 is held at the low speed or high speed position.

Conversely, when a command to reduce the working speed is issued from the command circuit B, the motor 37 is reversed and the engine 1 is switched from high speed to low speed or to an idling state.

This embodiment is characterized by the use of a motor 37 and a variable resistor 39, so that the speed of the engine can be changed steplessly, but other functions and effects are the same as those of the previous embodiment.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can also be embodied in the following embodiments.

(1) In the embodiment described above, the tip of the wire 30 was slidably engaged with the elongated hole 14a of the actuating arm 14, but the tip of the wire 30 should be directly locked to the throttle lever 13. In this case as well, it is necessary to provide means such as a long hole to allow manual operation of the accelerator pedal 18.

(2) In a device incorporating the motor 37, a plurality of limit switches (not shown) are provided in place of the variable resistor 39, so that the cargo handling speed can be adjusted in several stages.

(3) The clutch switch 34 and the gear shift lever switch 35 are connected in series so that cargo handling work is performed only when both are closed.

(4) The work speed command circuit B should be configured by, for example, a switching circuit other than a computer.

(5) In the above embodiment, an engine-type forklift was explained, but it should be applied to a battery-type forklift. In this case, the hydraulic motors for traveling and cargo handling are combined into one.

As detailed above, the present invention provides a manual transmission mechanism that converts the traveling speed and cargo handling speed by manually controlling the rotational speed of the same power source, and a manual transmission mechanism that detects the power disconnection state between the power source and the traveling wheels. a detecting means for outputting a traveling power disconnection signal; a working speed command circuit configured to output a working speed conversion command signal for cargo handling, etc. to the power source; a traveling power disconnection signal is output from the detecting means; A discrimination circuit that outputs a work speed conversion signal for cargo handling, etc. only when a work speed conversion command signal for cargo handling, etc. is output from the work speed command circuit, and a work speed conversion signal for cargo handling, etc. from the discrimination circuit. An automatic system that automatically changes the rotational speed of the power source to change the speed of work such as cargo handling, and maintains the power source at a low speed when a traveling power contact signal is output from the detection means. The following effects are achieved by comprising a speed change mechanism and an operation permitting means that allows manual operation of the manual speed change mechanism regardless of work speed conversion operations such as cargo handling by the automatic speed change mechanism. In other words, when the vehicle is forced to travel by a power source, it prevents work such as cargo handling from being carried out in response to signals from the command circuit, thereby eliminating runaway behavior, eliminating falling cargo and personal accidents, and improving safety. There are effects that can be enhanced.

[Brief explanation of drawings]

Fig. 1 is a block circuit diagram embodying the working speed control device of the present invention in an engine-type forklift, Fig. 2 is an electric circuit diagram showing one embodiment of the working speed control device of the present invention, and Fig. 3 is a block circuit diagram showing an embodiment of the working speed control device of the present invention. It is a front view which shows another example of an automatic transmission mechanism. Wire...30, clutch switch...34,
Gear lever switch...35, electromagnetic solenoid...
...MS ₁ , MS ₂ , relay...R ₁ , R ₂ , detection means...
...A, Working speed command circuit...B, Discrimination circuit...
C. Automatic transmission mechanism...D.

Claims (1)

[Scope of Claims] 1. In an industrial vehicle in which running wheels are driven by the same power source to perform traveling operations, and lift cylinders, etc. are driven to perform cargo handling and other operations, the rotational speed of the power source is a manual transmission mechanism that manually operates to convert traveling speed and work speed for cargo handling, etc.; a detection means that detects a power disconnection state between the power source and the running wheels and outputs a traveling power disconnection signal; On the other hand, a working speed command circuit outputs a working speed conversion command signal for cargo handling, etc., and a traveling power disconnection signal is output from the detection means,
and a determination circuit configured to output a work speed conversion signal for cargo handling, etc. only when a work speed conversion command signal for cargo handling, etc. is output from the work speed command circuit; The rotational speed of the power source is automatically changed in response to a signal to change the speed of work such as cargo handling, and the power source is maintained at a low speed when a traveling power contact signal is output from the detection means. A working speed control device for an industrial vehicle, comprising: an automatic transmission mechanism; and an operation permitting means that allows manual operation of the manual transmission mechanism regardless of work speed conversion operations such as cargo handling by the automatic transmission mechanism. . 2. The detection means is constituted by a clutch switch and a gear lever switch that are operated when the clutch connected between the power source and the running wheels and the gear lever operating the transmission are in the disengaged state and the neutral state, respectively. Claim No. 1
A working speed control device for an industrial vehicle as described in 2. 3 The discrimination circuit is composed of a plurality of relays that are excited by the cargo handling speed conversion signal from the work speed command circuit, and the operating voltage as a running power cutoff signal from the detection means is applied to the normally open contacts of these relays. 3. A working speed control device for an industrial vehicle according to claim 1 or 2, wherein: 4. The automatic transmission mechanism includes a plurality of electromagnetic solenoids excited by a cargo handling speed conversion signal from a discrimination circuit, and a wire that is pulled by these rods so that the speed of the power source can be changed in stages. Claim 1 or 3 consisting of
A working speed control device for an industrial vehicle as described in 2. 5. The automatic transmission mechanism includes a motor whose rotation is controlled by a cargo handling speed conversion signal from a discrimination circuit, a wire which is tensioned by the rotation of the motor, and which adjusts the power source steplessly. 4. A work speed control device for an industrial vehicle according to claim 1, further comprising an angle detector configured to detect the rotation angle of the motor and stop the motor. 6. The operation permitting means that allows the manual transmission mechanism to be operated regardless of the operation speed conversion operation for cargo handling or the like by the automatic transmission mechanism is an operation permitting means connected between an accelerator pedal and a throttle lever that constitute the manual transmission mechanism. The industrial vehicle according to claim 4, wherein the lever is formed with a long hole, and a connecting pin fixed to the tip of the wire of the automatic transmission mechanism is engaged in the long hole so as to be relatively movable. Work speed control device.