JPS6132219Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an operating device for a hydraulic circuit switching valve used to drive a working device in a large construction machine or the like.

(Prior Art and Problems) As construction machinery becomes larger, the capacity of the hydraulic circuit switching valve itself also tends to increase, and as a result, it becomes difficult to directly and manually switch the valve. As a result, a force assist device is required to operate this valve.

Further, it is desired that the operation of a working device such as a construction machine, for example, a shovel of a shovel loader, accurately follows the operating intention of the operator in terms of work agility or risk prevention.

Conventional operating force assist devices have used a remote control system that uses hydraulic pressure.
As a result, there is an unavoidable time delay between the operator's operation and the actuation of the hydraulic circuit switching valve via hydraulic pressure, making it impossible to accurately follow the operator's operating intentions. In other words, it goes without saying that the agility of the work is lacking, but in order to avoid unexpected accidents during work, if the shovel of a shovel loader suddenly stops or moves, the operator's instantaneous control becomes difficult. However, the disadvantage was that accidents were inevitable due to the time delay.

In addition, this hydraulic remote control method
This required a hydraulic pump, pressure regulating valve, hydraulic piping, etc., resulting in high costs.

(Purpose of the invention) The present invention replaces the conventional hydraulic remote control system with a hydraulic circuit switching valve that is mechanically linked to accurately follow the operator's operating intention, and is commonly used in large construction machinery, etc. An object of the present invention is to obtain an operating device for a hydraulic circuit switching valve using compressed air for a brake booster provided therein.

(Configuration of the invention) The configuration of the hydraulic circuit switching valve operating device of the invention includes a bracket on which a pilot valve is installed,
The piston rod of the air cylinder is connected to the bracket, and the air cylinder has its base end pivotally connected to a member such as a frame, and an operating lever that is pivotally supported by the frame or other member and operates the pilot valve. The cylinder is piped from an air tank so as to be supplied and exhausted through the pilot valve, and the bracket is connected to a spool with a return spring of a hydraulic circuit switching valve fixed to a member such as a frame.

(Function) The pilot valve is switched by operating the operating lever, the piston rod of the air cylinder is extended via piping from the air tank, and the bracket equipped with the pilot valve moves forward.

As the bracket advances, the spool advances, the hydraulic circuit switching valve switches, and the working device is driven.

As the bracket moves forward, the pilot valve moves to the same position as before operating the operating lever, and the pilot valve returns and the spool is returned by the return spring, thereby stopping the driving of the working device.

Furthermore, if the operator releases the lever while the operator is operating the lever, the spool is automatically returned by the return spring, the hydraulic circuit switching valve is closed, and the working device is immediately stopped.

(Example) An example of the present invention will be described with reference to the drawings. In FIG. 1, A is an operating device for a hydraulic circuit switching valve, and 1 is a frame of a vehicle body or the like. A hydraulic circuit switching valve 2 with a return spring is fixed to this frame 1, and a swing fulcrum 13 of an operating lever 4 is rotatably supported.
A bracket 5 is not fixed to the frame 1, and two pilot valves 8, 8 are fixedly attached to the bracket 5. Then,
A bracket 5 provided with two pilot valves 8, 8 is connected to the frame 1 by an air cylinder 6, with the operating point 14 of the operating lever 4 positioned between the pilot valves 8, 8. There is.
The air cylinder 6 has a proximal end 6a pivotally attached to the frame 1, and a piston rod 11 extending and retracting from the distal end 6b, whose distal end is pivotally attached to the bracket 5. Note that 12 is a piston. In this way, the bracket connected to the frame 1 by the air cylinder 6 is further connected to the spool 3 of the hydraulic circuit switching valve 2. The bracket 5 is connected to the spool 3 of the hydraulic circuit switching valve 2 so that one end thereof is substantially supported by the frame 1, and the other end is also provided with a long hole (not shown) in the bracket 5, for example. The operating point 14 of the operating lever 4 is fitted into the elongated hole and is substantially supported by the frame 1. Reference numeral 7 denotes an air tank normally provided in large construction machines, etc., for example, an air tank used for brake boosting. Reference numeral 9 represents an air pipe connecting the air tank 7 and the pilot valve 8, and reference numeral 10 represents an air pipe connecting the pilot valve 8 and the air cylinder 6.

FIG. 2 is an explanatory diagram of the air circuit, in which the pilot valve 8 is provided with an air supply passage 801 and an exhaust passage 802, and the air supply passage 801 communicates with the pipe 9 communicating with the air tank 7 and the air cylinder 6. The exhaust path 802 can be connected to the pipe 10 at the same time, and the exhaust path 802 can be connected only to the pipe 10. The pilot valves 8 are provided in pairs before and after the point of action 14 of the operating lever 4, and each pilot valve 8 is normally set to a neutral position. That is, one end of the pipe 9 that communicates with the air tank 7 is closed, and one end of the pipe 10 that communicates with the air cylinder 6 is opened to the outside air through the exhaust path 802.

The above-mentioned pipe 9 has its base end connected to the air tank 7, and branches into two pipes 9a and 9b from the middle,
One pipe 9a is connected to one pilot valve 8a, and the other pipe 9b is connected to the other pilot valve 8b.

Further, a pair of the above-mentioned pipes 10 are provided corresponding to the pair of pilot valves 8a and 8b. In the normal state, one end of one pipe 10a is connected to the exhaust passage 802 of one pilot valve 8a.
The other end is connected to the base end 6a of the air cylinder 6. Also, one end of the other pipe 10b is normally connected to the exhaust path 802 of the other pilot valve 8b.
The other end is connected to the tip side 6b of the air cylinder 6.

Next, the operation of the hydraulic circuit switching valve operating device A configured as described above will be explained.

First, by starting to operate the operating lever 4, the point of action 14 slides, for example, through an elongated hole opened in the bracket 5, and one of the pilot valves 8 fixed to the bracket 5 is switched.

Now, when one of the pilot valves 8a is switched, the air supply path 801 connects the pipe 9a and the pipe 10a to forcefully send air from the air tank 7 to the base end 6a of the air cylinder 6. As a result, the piston 12 is pressed toward the distal end, causing the piston rod 11 to extend and press the bracket 5. At this time, air from the tip side 6b of the air cylinder 6 is transferred from the pipe 10b to the other pilot valve 8.
It is discharged to the outside air through the exhaust passage 802 of b.

When the bracket 5 is pressed as described above, the spool 3 of the hydraulic circuit switching valve 2 begins to be pulled against the return spring. At this time, since the pilot valve 8 is fixed on the bracket 5, the relative position of the pilot valve 8 to the point of action 14 of the operating lever 4 is the same as before the operation of the operating lever 4 starts, and both are in a neutral state. Move up to. By repeating this operation continuously, the movement of the operating lever 4 and the hydraulic circuit switching valve 2
The movement of the spool 3 follows, the hydraulic circuit is configured into a desired circuit, and a predetermined working device is driven. Furthermore, if you release your hand from the operating lever 4 while it is being operated, the spool 3 of the hydraulic circuit switching valve 2 will automatically return to its original position due to the built-in return spring, closing the hydraulic circuit and stopping the work equipment. do.

Although two pilot valves were used in this example, one pilot valve with three positions was used, which had the same purpose.
It is also possible to configure the system with several pilot valves.

(Effects) The present invention fixes the hydraulic circuit switching valve to a member such as a frame, rotatably supports the swinging fulcrum of the operating lever, and attaches the pilot valve to a movable bracket that is not fixed to the frame or other member. With the operating point of the operating lever located at the neutral position of this pilot valve, connect the frame and other members with the bracket using an air cylinder, and connect the bracket and the spool with a built-in return spring of the hydraulic circuit switching valve. Because they are mechanically linked, there is no time delay, and the hydraulic circuit switching valve is switched at the same time as the operation lever is operated, allowing the work equipment to accurately follow the operation intention, which not only improves work agility but also prevents unexpected accidents. In addition, since the return spring built into the hydraulic circuit switching valve causes the operating lever to return to neutral, it is possible to more completely follow the stopping action of the work equipment and the operating intention, and the operating intention and work It is possible to obtain a hydraulic circuit switching valve operating device in which the operations of the devices are completely matched.

Furthermore, since it uses compressed air for a brake booster normally provided in large construction machines and has a simple structure, it can be an inexpensive device.

[Brief explanation of the drawing]

FIG. 1 is a side view of an embodiment of the hydraulic circuit switching valve operating device according to the present invention, and FIG. 2 is an explanatory diagram of the normal air circuit of the same device. A... Hydraulic circuit switching valve operating device, 1...
Frame, 2...Hydraulic circuit switching valve, 3...Spool, 4...Operation lever, 5...Bracket,
6...Air cylinder, 7...Air tank, 8...
pilot valve.

Claims (1)

[Scope of utility model registration request] A bracket on which a pilot valve is installed, an air cylinder to which a piston rod of an air cylinder is connected to the bracket and whose base end is pivoted to a member such as a frame, and which is pivotally supported by the member such as the frame and operates the pilot valve. The air cylinder is connected to a spool with a return spring of a hydraulic circuit switching valve fixed to a member such as a frame, and the air cylinder is piped from an air tank so as to supply and exhaust air through the pilot valve. An operating device for a hydraulic circuit switching valve.