JPS5819433B2 - impact power tool - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an impact power tool in which a tool such as a chisel is struck by a piston that is raised and lowered using hydraulic pressure and gas pressure, and the hydraulic circuit is switched as the piston moves up and down. The cylindrical valve moves up and down, allowing oil to enter and exit the lower chamber between the lower part of the large diameter part of the piston and the liner, and compressing the gas by the ascending piston to quickly lower the piston. Restoration is carried out using a lifting rod that is pressed down by hydraulic pressure on a spring mechanism, and gas is collected by inserting the upper end of the piston directly into the gas reservoir chamber without using an accumulator, thereby increasing durability and reducing costs. The details are as follows.

In the figure, 1 is a cylinder, 23 is a liner fixed inside the cylinder, liner 3 is the upper end of liner 2; it fits on the outside,
A cylindrical gap 4 is formed between the liner 2 and the inner side of the cylinder 1.

A piston 5 is fitted into the liner 2, and its large diameter portion 6 slides within the liner 2.

Further, within the gap 4, a cylindrical valve 7 is slidably fitted to the outside of the liner 2.

6 is a valve box fixed to the outside of cylinder 1, and this valve box 8
an oil supply pipe connection port 9 and an oil drain pipe connection port 10 that communicate with the hydraulic unit; an annular chamber 11 between the inside of the valve box 8 and the liner 23;
The same (forms an oil supply port 12 and an oil drain port 13 that communicate the inside of the valve box 8 and the gap 4).

14 is a bundle mounting member fixed on the cylinder 1;
An operating lever 17 of a valve body 16 fitted in the valve box 8 is pivotally connected to a handle 15 fixed to this member 14.

The valve body 16 is pushed toward the lever 17 by a spring 18, and when the lever 17 is not pressed, the connection port 910, oil filler port 12, and oil drain port 13 communicate with each other, and the lever 17 pushes the valve body 16. Then, the connection port 910 and the oil fill port 12 and the oil drain port 13 are cut off, and the connection port 9 and the oil fill port 12 and the connection port 10 and the oil drain port 13 are made to communicate with each other.

Communication holes 192021 communicating between the inside and outside of the liner 2 are sequentially formed from the bottom, and circumferential grooves are formed inside and outside the liner 2 at the portion where the communication holes 192021 are formed.

Further, a communication hole 22 communicating with the annular chamber 11 is formed in the liner 2 in the axial direction, and a communication hole 2324 is formed to communicate the communication hole 22 with the outside of the liner 2.

Further, inside the cylindrical valve 7, there are formed a circumferential groove 25 that communicates the descending verse communication holes 19 and 23 and a circumferential groove 26 that communicates the upward communication holes 20 and 24.

In addition, a plurality of vertical holes 27 are formed in the liner 3 that reach the annular chamber 11 from its lower end, and a lifting rod 28 is fitted into each of the vertical holes 27 so that its lower end contacts the upper end of the cylindrical valve 7. .

Therefore, the outer diameter of the liner 2 is made slightly smaller in the portion above the outer circumferential groove of the communication hole 20, and the inner periphery of the upper end of the cylindrical valve 7 has a diameter that slides into contact with the small diameter portion, and a stepped portion 29 is formed at the lower end. , and the lower surface area of the stepped portion 29 is larger than the total cross-sectional area of the lifting rod 28.

30 is a chisel holder screwed onto the lower end of cylinder 1;
1 is a chisel.

Further, a head 32 is provided at the upper end of the nozzle attachment member 14.
is fixed, the inside of this head 32 and member 14 is used as a gas reservoir chamber 33, and a supply port 34 with a check valve for supplying nitrogen gas or air is provided to this chamber 33.

The present invention has the above configuration, and when the chisel 31 is pressed against the object as shown in the figure and the operating lever 17 is not pressed, the oil flowing into the valve box 8 from the connecting port 9 passes through the valve box 8 and connects. There is no hydraulic pressure in the cylinder 1 as it returns to the tank through the port 10, so the piston 5 remains down.

Now, when the lever 17 is pressed down and the valve body 16 is lowered against the spring 18, and the connection port 910 is shut off, the pressure oil is transferred to the oil supply port 12.
Pressure oil flows into the annular chamber 11 from above, applies hydraulic pressure to the upper end of the lifting rod 28, and flows into the communication hole 22.
It flows into the liner 2 from the communication hole 19 through the circumferential groove 25 in the cylindrical valve 7, and flows between the lower part of the large diameter portion 6 of the piston 50 and the liner 2.
Apply hydraulic pressure to the lower chamber between.

At this time, since the gap between the outer circumference of the piston on the upper side of the large diameter part 6 and the inner circumference of the liner 2 communicates with the oil drain port 13 through the communication hole 21, the piston 5 is raised by the hydraulic pressure applied to the lower end of the large diameter part 6. .

When the lower end of the large diameter portion 6 is above the communication hole 20, the large diameter portion 6
Part of the pressure oil that was applying hydraulic pressure to the lower chamber at the lower end of the
0 into the cylindrical valve 7 and applies hydraulic pressure to the stepped portion 29 thereof.

Therefore, the cylindrical valve 7 pushes up the lifting rod 28 and rises, and the circumferential groove 26 communicates with the communication hole 2024, and the lower end of the valve 7 becomes above the communication hole 19. Therefore, the gap 4 becomes the communication hole 19.
Since the liner 2 is connected to the inside of the liner 2, the oil that was applying hydraulic pressure to the lower part of the large diameter portion 6 is discharged to the oil drain port 13 through the communication hole 19 and the gap 4.

On the other hand, when the piston 5 rises, the gas in the chamber 33 is compressed and becomes high pressure, so when the hydraulic pressure applied to the lower end of the large diameter portion 6 is removed as described above, the piston 5 is rapidly moved by the gas pressure. It descends and strikes the upper end of the chisel 31 with its lower end.

In this way, the piston 5 descends and the upper end of the large diameter portion 6 connects to the communication hole 2.
When the temperature falls below 0, the gap between the outer periphery of the piston 5 above the large diameter portion 6 and the liner 2 communicates with the communication hole 20° 21, so that the pressure oil applied to the circumferential groove 26 of the cylindrical valve 70 is drained. Mouth 13
is discharged to.

Therefore, when the valve 7 is pushed down by the pressing force of the lifting rod 28 and reaches the lowest position, the previous operation starts.

While pressing the operating lever 17 and pressing down the valve body 16, the above operation is repeated, the piston 5 moves up and down, and the chisel 3
When 1 is pressed repeatedly and the pressure on the lever 17 is released, the valve body 16 is raised by the spring 18, and no hydraulic pressure is applied to the oil filler port 12, and the piston 5 is stopped.

The present invention performs the above-mentioned operation, and uses a cylindrical valve 7, which is slidably fitted to the outside of the liner 2 in the cylinder 1, and which is moved up and down by being pushed down by hydraulic pressure. Since it is pressed down using the rod 28, it is superior to the conventional method of pressing down using a spring in that there is no risk of insufficient pressing force due to deterioration of the spring or failure due to breakage of the spring.

Furthermore, in the past, an accumulator was provided at the upper end of the cylinder 1, but in the present invention, it is only necessary to provide the gas reservoir chamber 33 at the upper end of the cylinder 1, so the structure is simplified and manufacturing costs can be reduced. be.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional side view of the tool of the present invention. 1...Cylinder, 23...Liner, 4
...Gap, 5...Piston, 6...
... Large diameter part, 7 ... Cylindrical valve, 12 ...
・Fuel filler port, 13...Oil drain port, 28...
Lifting rod, 30...Chisel holder, 31...
...Chisel, 33... Gas storage room.

Claims (1)

[Claims] 1 A liner is fixed with a cylindrical gap in the cylinder, a piston with a large diameter part formed in the middle is fitted in the litchi, and a chisel holder fixed to the lower end of the cylinder is struck by the piston. A chisel is attached to the outside of the liner, and the pressure oil that flows in from the oil supply port of the cylinder when descending is supplied to the royal area between the inside of the liner and the lower part of the large diameter part of the piston to push the piston upward, and when it goes up, it A cylindrical valve that functions to discharge royal oil is slidably fitted into the cylinder, and an elevating rod that presses down the cylindrical valve with hydraulic pressure is attached to the cylinder, and the upper end of the cylinder is compressed by a raised piston. An impact power tool having a gas reservoir chamber filled with gas, and a hydraulic circuit provided in the cylinder and liner to hydraulically raise the cylindrical valve when the piston descends, and to push the cylindrical valve down by the lifting rod when the piston ascends. .