JPH0243422A - Burglaproof switch device for construction machine - Google Patents

Abstract

PURPOSE:To make it impossible for a burglar to operate a machine to prevent burglary by attaching burglaproof key switch on an optional position of the machine in parallel with a limit switch for a solenoid valve intercepting an oil passage for a remote control valve. CONSTITUTION:A burglaproof key switch 34 is attached to a secret position in parallel with a limit switch 17 on an electric circuit running from a solenoid valve 27 located on an oil passage connecting a pilot pump 26 and a remote control valve 23 to a power supply 31. When a control box 6 is turned backward, a key switch 30 for engine is opened to stop the operation of a hydraulic shovel, and the shovel is left as it is, the burglaproof switch 34 located on the secret position is operated ON. Under the condition, even when the key switch 30 is closed to turn the box 6 forward, the shovel cannot be operated since the key switch 34 is closed and the solenoid valve 27 is at an oil passage intercepting position.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates primarily to a theft prevention switch device for construction machinery, industrial vehicles, and the like.

BACKGROUND OF THE INVENTION FIG. 2 is a partially cutaway side view of a hydraulic excavator among construction machines. In the figure, 1 is a lower traveling body of a hydraulic excavator, 2 is an upper revolving body, 3 is a driver's cab provided in the upper revolving body 2, and 4 is a driver's seat in the driver's cab 3. Figure 3 shows
3 is a detailed view of part A in FIG. 2. FIG. In the figure, 5 is a control lever, 6 is a control box, 7 is a button type knob,
8 is a base, 9 is a floor plate, 10 is a support bracket, 11
12 is an arm, 12 is a bracket, 13 is a mechanical lock mechanism, 14 is a bushing bar, 15 is a push-pull cable, 16 is a contact, and 17 is a limit switch. FIG. 4 is a lock circuit diagram for a conventional operating lever.
In the figure, 18 is a hydraulic cylinder among various hydraulic actuators equipped on the hydraulic excavator, 19 is a pilot switching valve, 20.21 is a pilot pressure receiving part on the left and right sides of the pilot switching valve 19, 22 is a main pump, 23 is a remote control valve, 24 and 25 are respective pilot valves of the remote control valve 23, 26 is a pilot pump, 27 is a solenoid valve, 28 is a truid of the solenoid valve 27, 29 is a battery relay, and 30 is an engine key switch 31 which is a power source.

Next, the configuration of a lock circuit for an operating lever in the prior art will be described with reference to FIGS. 3 and 4.

A control box 6 is provided on the left and right front sides of the driver's seat 4 so as to be tiltable in the front-rear direction, and an operating lever 5 for a remote control valve 23 for switching and controlling pilot switching valves 19 for various hydraulic actuators is provided on the top of the control box 6. A contactor 16 is provided in the box 6. On the other hand, a limit switch 17 is fixedly attached to the base stand 8 on the side of the driver's seat 4, and when the control box 6 is rotated to the rear end position A, the contactor 16 comes into contact with the limit switch 17, and the pilot pump 26 and the remote control valve 23, the solenoid valve 27 interposed in the oil passage is configured to be switched to the oil passage blocking position.

Next, the functions of the lock circuit for the operating lever in the prior art will be described. When the knob 7 provided at the top of the control box 6 is pushed downward (in the direction of the arrow), the pushing force acts on the mechanical locking mechanism 13 via the pusher 14 and the push-pull cable 15. Release the lock operation. Therefore, by keeping the knob 7 pressed, the control box 6 can be adjusted to tilt with a light force. The control box 6 can be tilted within a range of angle α from the rear end position A. When the driver tilts the control box 6 to a desired angular position optimal for operation and releases his/her finger from the knob 7, the knob 7 returns to its original position and the mechanical lock mechanism 13 becomes locked, locking the control box 6. Box 6 is fixed. Therefore, in order to inspect the aircraft, the driver may get off the aircraft with the engine key switch 3o still in the ON state. At that time, the driver returns the control box 6 to the rearmost position A. Then, the contact 16 provided on the control box 6 hits the limit switch 17 attached to the base 8 on the side of the driver's seat 4. come into contact with As a result, the solenoid 28 of the solenoid valve 27 becomes energized, and the solenoid valve 27 is switched from the oil passage opening position C to the oil passage blocking position 2. Therefore, pressure oil is supplied from the pilot pump 26 to the remote control valve 2.
3 will be blocked. In this state, the operating lever 5
Even if the is operated in the direction of the E position or the direction of the H position, pilot pressure is not drawn out to the pilot switching valve 19.
Therefore, even if a part of the driver's body comes into contact with the control lever 5 when the driver gets out of the vehicle, the actuator will not start operating unexpectedly. By returning it, the operating lever 5 is locked.

Problems to be Solved by the Invention Due to production management and other reasons, the engine key switch for hydraulic excavators allows the use of a common key, unlike for automobiles. Otherwise, a thief could use another common key to move the excavator to another location.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and provide an anti-theft switch device in which a key switch is provided in a lock circuit for an operating lever.

Means for Solving the Problem A. The solenoid of the solenoid valve interposed in the pilot pressure oil passage that communicates the pilot pump and the remote control valve is connected to the electric circuit connected to the power source by the solenoid of the solenoid valve in parallel with the limit switch to prevent theft. In addition to providing a key switch for the aircraft, the above-mentioned key switch was installed at any arbitrary position on the fuselage.

Function A. An anti-theft key switch was installed in parallel with the above limit switch in the electric circuit leading from the solenoid valve to the power source. Therefore, if the anti-theft key switch is turned on, the operating lever will be in a locked state even if the engine is operated and the control box is tilted.

Therefore, even if the engine mounted on the hydraulic excavator is rotated, the hydraulic excavator cannot be operated and moved.

Since the key switch is located at a quiet position on the body of the hydraulic excavator, its position is known only to a limited number of people, such as the operator of the hydraulic excavator. Therefore, it is difficult for another person to find the key switch and open its circuit, thereby preventing the hydraulic excavator from being stolen.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings. FIG. 1 is a circuit diagram showing a switch device according to the present invention. In FIG. Next, the configuration of the switch device according to the present invention will be described with reference to FIG. Pilot pump 2
The solenoid 2 of the solenoid valve 27 interposed in the pilot pressure oil passage communicating between the solenoid valve 6 and the remote control valve 23.
An anti-theft key switch 34 is disposed in parallel with the limit switch 17 in an electric circuit connected to a power source 31 from 8. At the same time, the switch 34 was installed at any arbitrary position on the fuselage. Note that instead of using only one anti-theft key switch, a plurality of key switches may be connected in parallel and each of the plurality of key switches may be arranged at a plurality of safe positions.

Next, the functions of the switch device according to the present invention will be described. The control box 6 is returned to the rear end and the engine key switch 30 is opened to stop the operation of the hydraulic excavator. When the hydraulic excavator is left unattended, the theft prevention key switch 34 disposed at any rest position of the hydraulic excavator is turned on. By doing this, even if the engine key switch 30 is turned on and the control box 6 is tilted forward to open the limit switch 17, the anti-theft key switch 34 will be closed.
is closed, so the solenoid 28 is energized. As a result, the solenoid valve 27 is in the oil passage blocking position 2, so the operating lever 5 remains in the locked state. Therefore, even if the engine (not shown) mounted on the hydraulic excavator is rotated, the hydraulic excavator cannot be operated and moved, and the anti-theft key switch 34 is disposed at a quiet position on the hydraulic excavator body. Therefore, only a limited number of people, such as the operator of the hydraulic excavator mentioned above, know its location.

Therefore, it is difficult for another person to find the key switch 34 and open the circuit. This prevents the hydraulic excavator from being stolen.

Effects of the Invention For reasons such as manufacturing control, the key switch for the engine of a hydraulic excavator is designed so that a common key can be used, unlike in the case of automobiles.

Therefore, if the hydraulic excavator of the prior art is left unattended, a thief may use another common key switch to move the excavator to another location.

However, in the switch device according to the present invention, an anti-theft key switch is disposed in an electric circuit connected to a power source from a solenoid of a solenoid valve interposed in an oil passage communicating between a pilot pump and a remote control valve, and The above-mentioned key switch was arranged in any position of the hydraulic excavator body. As a result, if you turn on the anti-theft key switch and leave the hydraulic excavator unattended, even if a thief uses another engine key switch to start the engine and tilts the control box, the operation lever will not be removed. remains locked.

Further, since the anti-theft key switch is disposed at a quiet position on the body of the hydraulic excavator, it is difficult for a thief to find the key switch and open the circuit.

Therefore, even if a thief is able to start the engine of a construction machine equipped with the switch device according to the present invention, he or she will not be able to operate the construction machine, thereby preventing the theft of the construction machine. It can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a switch device according to the present invention;
FIG. 2 is a partially cutaway side view of the hydraulic excavator, FIG. 3 is a detailed view of section A in FIG. 2, and FIG. 4 is a lock circuit diagram for a conventional operating lever. Operation lever Control box Contactor Limit switch Pilot switching valve Remote control valve Pilot pump Solenoid valve Solenoid Engine key switch Anti-theft key switch Patent application Toshiaki Kanagawa, representative of Jin Yutani Heavy Industries Co., Ltd. Figure

Claims (1)

[Claims] A control box that can be tilted forward and backward is provided on the left and right front sides of the driver's seat, and a remote control valve operating lever that switches and controls the pilot switching valves for various hydraulic actuators is provided on the top of the control box, and the control box can be rotated to the rear end. In the lock circuit for the operation lever, which shuts off the pressure oil supply line for the remote control valve by operating the limit switch when tilted, an anti-theft key is provided in parallel with the limit switch in the electric circuit leading from the solenoid valve to the power source. A switch device for preventing theft of construction machinery, characterized in that a switch is provided and the key switch is mounted at any arbitrary position on the machine body.