JPH0352190Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an electric circuit for a footlight for getting off a construction machine.

BACKGROUND OF THE INVENTION After completing nighttime work using a construction machine, the driver may exit the machine from the operator's cab. For safety, the driver locks the operating lever, turns off all lighting devices, removes the key switch, opens the driver's cabin door, and exits the aircraft through the exit. In that case, it was very inconvenient because it was dark outside the aircraft and I couldn't see my feet clearly. Although not shown, countermeasures such as footlights, limit switches, transistors, etc. are installed on construction machinery, work vehicles, etc.
Various methods have been considered for arranging charging capacitors and the like to keep the footlights on for a predetermined period of time when the driver exits the vehicle.

Problems to be Solved by the Invention In prior art construction machines, all lighting devices are turned off when the operator pulls out the key switch after completing night work. As a result, if the driver did not have a flashlight or other external lighting available, it would be dark underfoot. Therefore, when the driver landed on the ground outside the aircraft, his footing was poor and he could, for example, step into a hole and fall, or he could trip over an obstacle and get injured, which was a safety hazard.

Means for Solving the Problems The means of this invention taken to solve the above problems are as follows: (1) The construction machine is provided with a limit switch that is turned on in conjunction with a solenoid valve for locking the work operation lever; The limit switch is connected in series with a DC power supply, a key switch, and a solenoid of a solenoid valve. (b) A charging circuit is also provided from the DC power supply through a diode, a transistor, and a capacitor to the footlight. (c) A transistor and a resistor are connected to the DC power supply. Arrange a capacitor and a resistor and connect them to the upstream side of the limit switch to form a trigger generation circuit. (2) On the other hand, connect the DC power supply side to another transistor, and connect its emitter terminal to the foot lamp to turn on the foot lamp. A means circuit is provided, e) a transistor in the trigger generating means circuit,
When the capacitor in the above circuit is charged, it can be turned on, and when the solenoid valve for operating lever lock is operated and the key switch is removed, the capacitor in the charging circuit is turned on until the capacitor in the charging circuit ends in discharge in item B above. The lighting current for the footlights is passed through the footlight lighting means circuit described in section 3.

Operation A: When the key switch of the construction machine is turned on and the operating lever lock is released, the limit switch is open, but at that time, the current from the DC power supply passes through the charging circuit, and the diode, Charges the capacitor via the transistor.

When the lock switch is removed and the operating lever is locked, the limit switch is closed, so the transistor in the trigger generating means circuit is turned on and the transistor in the charging circuit is turned off.

C. While the transistor in the trigger generating means circuit is turned on, the transistor in the footlight lighting means circuit is turned on, and the current from the DC power supply passes through the transistor to the footlight, and the charging The charged capacitor in the electrical circuit is discharged, and the footlight continues to be lit until the time constant has elapsed.

D. Since the limit switch remains closed even after the capacitor in the charging circuit has finished discharging, the transistor in the charging circuit is turned on, but the footlight remains off.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings. Figure 1 is an electric circuit diagram of the footlight for getting off the vehicle according to the present invention. In the figure, 1 is a DC power supply, 2
is the key switch, 3 is the fuse for this circuit, 4, 5
6 is a fuse for other electrical loads, 6 is a diode to avoid grounding from other electrical loads, 7 is a limit switch for driving a solenoid for operating lever lock (not shown), 8 is a solenoid valve, 9, 10, 12, 13
is a transistor, 11 and 17 are capacitors, 1
4, 16, 18, 19, 20, 21 are resistances, 15
2 is a footlight installed near the exit outside the driver's cabin.
2 is a diode. Therefore, the DC power supply 1, key switch 2, fuse 3, diode 6, limit switch 7, and solenoid valve 8 are connected in series and grounded. Also, DC power supply 1 and key switch 2
The transistor 10 is grounded from the communication line 23 through the electric lines 24 and 25, the diode 22, the transistor 10, the capacitor 11, and the foot lamp 15.
The charging circuit is connected. Also, DC power supply 1
The collector terminal of the transistor 12 is connected through the electric lines 23 and 24, the collector terminal and the base terminal of the transistor 12 are connected via the resistor 16, and the base terminal of the transistor 12 is connected to the capacitor 17 and the resistor 18 in parallel. The trigger generating circuit A is arranged and connected to the upstream point of the limit switch 7 to form a trigger generating means circuit A. On the other hand, another transistor 1 is connected to the DC power source 1 through electric circuits 23 and 24.
3 and 9 to form a complementary circuit, and the emitter terminal of the transistor 9 was connected to the positive side of the foot lamp 15 to form a foot lamp lighting means circuit B. For this purpose, a diode 22, a transistor 10, a capacitor 1
1. The charging circuit connected by resistors 19, 20, 21, and 14 forms a monostable multivibrator circuit C including a footlight lighting means circuit B.

The electric circuit of the present invention is constructed as described above, and its operational functions will now be described. When starting the operation of the construction machine, the driver sits in the driver's seat, turns on the key switch 2, and releases the lock for the operating lever. Therefore, key switch 2 is turned on and limit switch 7 is turned off, so
The point potential is 0, and the point potential is the power supply voltage. The driver then operates a control lever (not shown) to perform the work. At that time, transistors 12,1
3 and 9 are in the off state, but a part of the current from the DC power source 1 flows through the electric lines 23, 24, 25 and the diode 2.
2. The collector terminal of the transistor 10, its base terminal, its emitter terminal, and the resistor 21 are grounded. A portion of the capacitor 11 is also grounded through the base terminal of the transistor 10 and the resistor 14, and the capacitor 11 is charged in a charging circuit which is connected from the base terminal of the transistor 10 through the capacitor 11 and the footlight 15 to ground. next,
After finishing the work with the construction machine, turn on the key switch 2.
and lock the operating lever. Then, the key switch 2 opens and the limit switch 7 closes, so that both the point and the point potential become 0. Therefore, the transistor 12 in the trigger generating means circuit A is turned on, so that the current from the DC power source 1 flows through the electric lines 23, 24, 25, the collector terminal of the transistor 12, its base terminal, the capacitor 17 and the resistor 18, the limit switch 7, and the solenoid valve. Grounded through 8. The trigger means of the trigger generating means circuit A turns on the transistor 12 and turns on the transistors 13 and 9 of the complementary circuit. However, since the transistor 10 is in an off state, the DC power supply 1
The current flows through the transistor 9 to the foot lamp 15 to turn it on. The lighting time continues until the time constant when the capacitor 11 finishes discharging. After the time constant has elapsed, the transistor 10 is turned on again, but
Transistors 13 and 9 are turned off, and foot lamp 15 is turned off. Therefore, after that, the footlight 15 remains in the off state.

Although the limit switch 7 of the present invention utilizes the limit switch 7 that operates the operating lever lock (solenoid) solenoid valve 8, another switch circuit may be used instead.

Effects of the invention As mentioned above, the electric circuit for the footlight for getting off the vehicle of the present invention includes a charging circuit that runs from the DC power source through a diode, a transistor, and a capacitor to the footlight, and also includes a transistor, a resistor, a capacitor, and a resistor in the DC power supply. A trigger generating means circuit was formed by connecting the trigger generator to the upstream side of the limit switch. On the other hand, connect another transistor to the DC power supply side,
A monostable multivibrator circuit including a footlight lighting means circuit was formed. When the transistor in the trigger generating circuit is turned on, the foot lamp can be turned on within the time constant of the capacitor in the monostable multivibrator circuit.

In prior art construction machines, all lighting devices are turned off when the operator pulls out the key switch at the end of nighttime work. For this purpose, they used flashlights and other external lights to get out of the cab. However, if there were no lights, it would be dark underfoot, and people would trip into holes and fall.
This was a safety hazard as people could trip over obstacles and injure themselves.

In this invention, when the driver finishes night work and locks the operating lever and pulls out the key switch, the footlight installed near the exit is automatically installed within the discharge time constant of the capacitor in the monostable multivibrator circuit. can be lit. for that,
The driver can get off the vehicle by visually observing his or her feet using the footlights, without using a flashlight or relying on any other external light. The limit switch in the electric circuit of the present invention can be used to operate the control lever lock solenoid installed on the construction machine, and the footlights automatically turn off after a short time constant, so the footlights can be turned off automatically after a short time constant. There is no chance of forgetting to turn it off or inadvertently discharging the DC power supply. Further, the footlight electric circuit of the present invention can be applied to any construction machine or work vehicle that has an operating lever, and since the main component is a transistor, it can be manufactured inexpensively and compactly. Therefore, when the driver gets off the construction machine after nighttime work, the footwell lighting can be automatically ensured for the minimum necessary time, improving safety.

[Brief explanation of drawings]

FIG. 1 is an electrical circuit diagram of the footlight for getting off the vehicle according to the present invention. 1...DC power supply, 2...Key switch, 7...
Limit switch, 9, 10, 12, 13... Transistor, 11, 17... Capacitor, 15...
...Footlight, 14, 16, 18, 19, 20, 21
……resistance.

Claims (1)

[Scope of utility model registration request] Limit switches, transistors, charging capacitors, etc. are installed to turn on the footlights installed on construction machinery, work vehicles, etc. When the driver gets off the vehicle, the limit switch is activated to turn on the footlights for a predetermined period of time. In the electric circuit that keeps the lights on, construction machinery
A limit switch 7 is provided which is turned on in conjunction with a solenoid valve 8 for locking a working operating lever.
The limit switch 7, the DC power supply 1, the key switch 2, and the solenoid of the solenoid valve 8 are connected in series, and an electric path is provided from the DC power supply 1 to the footlight 15 via the diode 22, the transistor 10, and the capacitor 11. The collector terminal of the transistor 12 is connected to the resistor 16, and the collector terminal and base terminal of the transistor 12 are connected to the resistor 16.
The base terminal of the transistor 12, the capacitor 17, and the resistor 18 are arranged in parallel and connected to the upstream side of the limit switch 7 to form a trigger generating circuit.
The terminals of the transistors 13 and 9 are connected to the respective collector terminals of the transistors 13 and 9, and the emitter terminal of the transistor 9 is connected to the positive side of the footlight 15.
The transistor 12 in the trigger generating means circuit can be turned on when the capacitor 17 is charged, and the transistors 13 and 9 can be turned on until the capacitor 11 has finished discharging when the operating lever lock solenoid valve 8 is operated and the key switch 2 is removed. An electrical circuit for a footlight for getting off a construction machine, characterized in that a lighting current is applied to the footlight 15 through the footlight 15.