JPH0218078Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The invention provides a swivel base on the vehicle frame so as to be freely swivelable.
The present invention relates to a hydraulic circuit for a work vehicle such as a high-altitude work vehicle in which an extendable and retractable boom is pivotally supported on the swivel base so that it can be raised and lowered.

(Prior Art) It is common practice to connect a manual switching valve between a hydraulic power source and the actuator as an operating means for controlling each actuator of the swivel base and boom, and to attach the manual switching valve to, for example, a workbench. It is being done. Furthermore, in order to prevent danger, it is well known to provide a throttle valve in the middle of the hydraulic piping as a means for limiting the maximum values of the swivel speed of the swivel table, the up-and-down speed of the boom, and the speed of expansion and contraction.

(Problem to be Solved) By the way, the opening degree of the throttle valve is set so that the speed reaches the maximum speed within a range that is considered absolutely safe under normal working conditions, but it is difficult for inexperienced workers to do so. may work too fast.

(Means for Solving the Problems) The present invention was made in view of the above-mentioned circumstances, and includes connecting a manual switching valve for controlling the actuator between the hydraulic power source and each actuator, and connecting the manual switching valve and the actuator to each other. The present invention is characterized in that a variable throttle valve that can be manually adjusted from the outside is interposed in the hydraulic system between and near the manual switching valve.

(Function) As a result, by manually adjusting the opening degree of the variable throttle valve installed near the manual switching valve, the maximum working speed of each actuator can be arbitrarily limited according to the skill level of the operator. .

(Example) Reference numeral 1 denotes an aerial work vehicle, on which a swivel base 3 is mounted on the vehicle body 2 so that the swivel can be controlled by a swivel motor 4, and the base end of a boom 5 is attached to the upper end of the swivel base 3. It is pivoted so that it can rise and fall freely. The boom 5 has a luffing angle controlled by a luffing cylinder 6 disposed between it and the swivel base 3, and is provided in a multi-stage telescoping type with a built-in telescopic cylinder 7 whose length is variable. A workbench 8 is installed at the tip of 5a.

Although not described in detail, the workbench 8 is configured to always maintain a horizontal state in response to the raising and lowering movements of the boom 5.

Next, the above-mentioned aerial work vehicle 1 is equipped with hydraulic equipment as shown in the hydraulic system diagram of FIG. First, as the actuator A that is supplied with pressure oil and performs various operations, there are provided a swing motor 4 that swings the swing base 3, a luffing cylinder 6 that moves the boom 5 up and down, and a telescoping cylinder 7 that extends and contracts the boom 5.
Further, as a manual switching valve for controlling the operation of each of the above-mentioned actuators, a vehicle-side manual switching valve B consisting of manual switching valves V1, V2, and V3 for turning, raising and lowering, and telescoping is arranged on the vehicle body 2 side. On the other hand, on the workbench 6 side, there are manual switching valves V for swinging, elevation, and telescoping that correspond to the vehicle-side manual switching valve B described above.
A manual switching valve C on the workbench side consisting of V4, V5, and V6 is provided.

In the vicinity of each manual switching valve V1 to V6, and to each manual switching valve V1 to V6 and each actuator 4,
Variable throttle valves 9 to 14, which can be manually adjusted from the outside, are interposed in the hydraulic system between the valves 6 and 7.

Note that 15 is a pump as a hydraulic power source for each actuator, and is driven by the power of the engine via a power extraction device.

That is, by driving the pump 15 to place a worker on the workbench 8, and controlling the manual switching valves V1 to V3 on the vehicle side or the manual changeover valves V4 to V6 on the workbench side, the workbench 8 It is possible to move the robot to an appropriate location in space and perform various types of high-altitude work.

In addition, by appropriately adjusting the opening degrees of the variable throttle valves 9 to 14 near the manual switching valves V1 to V6 from the vehicle side or the workbench side, the swinging speed of the swinging platform 3, the hoisting speed of the boom 5, and the lifting speed of the boom 5 can be adjusted. The speed of expansion and contraction can be arbitrarily limited depending on the skill level of the operator.

(Effects) As described above, according to the present invention, the operator can manually adjust the opening degree of the variable throttle valve installed near the manual switching valve from the outside, so that the maximum working speed of each actuator can be adjusted based on the operator's skill level. It can be easily and arbitrarily restricted depending on the situation. Therefore, even an unskilled worker can work at the maximum speed suitable for the worker, and the work can be done easily.

[Brief explanation of drawings]

The drawings illustrate an embodiment of the present invention, and FIG. 1 is an overall side view of the aerial work vehicle, and FIG. 2 is a hydraulic system diagram thereof. 1...Aerial work vehicle, 2...Pulley, 3...Swivel base, 4...Swivel motor, 5...Boom, 6...Luffing cylinder, 7...Telescopic cylinder, 9-14...
Variable throttle valve, 15...pump, V1 to V6...manual switching valve.

Claims (1)

[Scope of utility model registration request] A hydraulic circuit for a working vehicle in which a swivel base is rotatably provided on the vehicle frame, and an extendable boom is pivotally supported on the swivel base so as to be able to raise and lower, the hydraulic circuit having a hydraulic circuit between a hydraulic power source and each actuator of the swivel base and the boom. , connecting a manual switching valve to control the actuator,
A hydraulic circuit for a working vehicle, characterized in that a variable throttle valve that can be manually adjusted from the outside is interposed in the hydraulic system between the manual switching valve and the actuator and in the vicinity of the manual switching valve.