JPS6338240Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a safety device for a vehicle for working at height.

In conventional aerial work vehicles, the driver rides on a work platform attached to the tip of the boom, and from this work platform he can control the vehicle's running speed, steering, boom extension/retraction, vertical rotation of the boom, etc. was configured to operate. Furthermore, with aerial work vehicles, the stability of the vehicle deteriorates when the boom is rotated upwards, so when traveling in this condition, it is necessary to reduce the traveling speed as much as possible (0.8 km / h). ) On the other hand, when rotating the boom downward and moving over long distances in a stable condition, it is possible to move at a certain speed (3 km/h).
Since this is necessary, the running speed can be set to high or low.
A changeover switch was provided to change the stage.

However, with such conventional devices, regardless of the rotation angle of the boom, that is, whether the vehicle is stable or unstable, the vehicle can run at high speed simply by switching the changeover switch. Even in this case, there is a possibility that the vehicle will run at high speed due to driver's incorrect operation, and in the worst case, there is a danger that the vehicle will overturn.

The present invention eliminates the dangers of conventional devices and provides a safety device that makes it impossible for the vehicle to run at high speeds when the vehicle is in an unstable state, even if the changeover switch is switched to the high speed position due to driver error. This is what we are trying to provide.

Embodiments of the present invention will be described below with reference to the drawings.

In the figure, 1 is a vehicle body frame supported by front and rear wheels 2 and 3 so that it can run, 4 is a turntable that is rotatably supported in the horizontal direction via a swivel seat bearing 5, and 6 is a This is a boom with a workbench 6A attached to its tip and a boss 7 fixed to its base end via a mounting bracket 6B. are connected so that they can rotate in the vertical direction. In addition, 9
are reinforcing ribs of the turntable 4. The above configuration is the same as that of the conventional device and performs the same function, so a detailed explanation will be omitted, and the configuration that is the main part of the present invention will be described below. Reference numeral 10 denotes a cam member fixed to the outer periphery of the boss 7 so as to extend in the circumferential direction, and a limit switch 11 is fixed to the reinforcing rib 9 via a bracket 12 in the vicinity of the cam member 10. There is. The relationship between the limit switch 11 and the cam member 10 is constructed as shown in FIG. That is, when the boom 6 rotates upward from the horizontal state, the cam member 10
The contact state with the limit switch 11 is released and the limit switch 11 is turned OFF, and when the boom 6 rotates downward from the horizontal state, the cam member 10 and the limit switch 11 come into contact, and the limit switch 11 is turned ON. It is configured. And this limit switch 1
The first connection terminal is connected in a conventional high/low speed switching circuit and in series with the high speed switching contact of the changeover switch.

In the device of the present invention configured in this way, when the boom 6 is rotated upward with the high/low speed changeover switch switched to the high speed position, or when the high/low speed changeover switch is turned upward and the changeover switch is turned to the high speed position. Even if the switching operation is performed, the limit switch 11 is turned OFF when the boom 6 rotates upward from the horizontal state, so the high-speed travel circuit is opened, and high-speed travel is disabled and only low-speed travel is possible. Therefore, the present invention can reliably prevent the vehicle from running at high speed due to driver's erroneous operation, and can prevent the risk of the vehicle falling over, thereby eliminating the driver's psychological anxiety and improving work efficiency. This has the effect of further improving the quality of the product.

In addition, by providing such a safety device, it is possible to increase the amount of extension of the boom and increase the load that can be placed on the workbench, which is a practical benefit that improves the performance of the aerial work vehicle. It also has an effect that is hard to miss.

In the above embodiment, only the running of the vehicle was explained, but in a vehicle of the type where the engine speed is changed by a high-low speed changeover switch, not only running but also high-speed operation of the vehicle, that is, high-speed rotation of the turntable, is possible. or the boom cannot be extended or retracted at high speed. In addition, if it is equipped with a switch that not only changes the engine speed between high and low speeds, but also changes the amount of pressure oil supplied to the drive motor to change the vehicle speed between high and low speeds. It is possible to reduce the engine speed and prevent the increase in pressure oil to the drive motor, thereby preventing both high-speed operation and high-speed running of the vehicle, or configuring the vehicle to only be unable to run at high-speed. can.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which FIG. 1 is an overall side view, FIG. 2 is a partially enlarged view taken in the direction of arrow A, and FIG. 3 is a cross-sectional view taken along line -. DESCRIPTION OF SYMBOLS 1...Vehicle frame, 2...Front wheel, 3...Rear wheel, 4...Turntable, 5...Swivel seat bearing, 6...Boom, 7...Boss, 8...Pivot pin, 10...Cam member , 11...Limit switch.

Claims (1)

[Scope of utility model registration request] A vehicle body frame that is movably supported by front and rear wheels, a turntable that is rotatably attached to the vehicle body frame via a swivel seat bearing, and a boss that is fixed to the base end and is inserted through the boss. In an aerial work vehicle comprising a boom rotatably connected to the turntable in the vertical direction via a pivot pin, and a high-low speed switching circuit that switches operating speed such as traveling of the vehicle between high and low speeds, the outer periphery of the boss At the same time, a limit switch is fixed to the turntable so as to correspond to the cam member, and the connection terminal of the limit switch is connected to the high-speed switching circuit of the high-low speed switching circuit, and the rotation of the boom is After the movement angle reaches a predetermined angle or more, the cam member and the limit switch can be continuously turned off, and the circuit on the high-speed switching side is opened to disable only high-speed operation of the vehicle. Device.