DE2121172A1 - Striking tool for pneumatic-hydraulic operation - Google Patents

Description

PATENT LAWYERS

Dipl. Ing. E. Eder Dipl. Ing. K. Schieschki

Nippon Pneumatic Manufacturing Company Ltd., Osaka City / Japan

Impact tool for pneumatic-hydraulic operation

The invention relates to a hydraulic or gaseous Pressure, for example from air, nitrogen or the like. Impact tool to be operated.

The known impact tools work with compressed air or mechanically. In devices operated with compressed air, air is expelled with each stroke, so that the air consumption is very high is. A compressor must always be running to deliver the compressed air, which is associated with considerable exhaust noise

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is. In the case of mechanical devices, a cam is driven by an electric or compressed air motor which, as a result of the Vibrations often give rise to disturbances and are also associated with noise.

The invention creates an impact tool that does not require an air compressor. To achieve a vigorous Impact action is made use of hydraulic and pneumatic pressure. The impact tool according to the invention is with a rapid liquid ejection device which compressed the liquid to achieve a powerful impact Ejects gas quickly, 'wherein the high pressure gas is compressed by hydraulic pressure.

The impact tool according to the invention comprises a base body with an upper and a lower cylinder. An upper piston that can be actuated by gas pressure is located in the upper cylinder. A lower piston is located in the lower cylinder, which can be operated hydraulically. A chisel that can be moved up and down is attached to the bottom of the base body. When the lower piston is lifted together with the upper piston by the hydraulic pressure in the lower cylinder, the gas in the upper cylinder is compressed. When the two pistons reach top dead center, the oil in the lower cylinder is suddenly expelled. The pressure of the compressed gas in the upper cylinder quickly drives the two pistons downwards and the lower piston hits the chisel.

For a more detailed explanation of these and other features of the invention, reference is made to the drawing. It shows:

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Fig. 1 is a longitudinal section through an embodiment of the impact tool according to the invention and

2 shows an enlarged longitudinal section through the limiting valve of the striking tool.

The impact tool shown shows a base body 11 with an upper cylinder 12 and a lower cylinder 13. Im Upper cylinder 12 sits the upper piston 14. The lower piston 15 is located in the lower cylinder 13. At the lower end of the Base body, the chisel 17 is fitted into a chisel holder 16. The two pistons 14 and 15 exist together with the Piston rod 18 from one piece. The upper piston 14 has a larger diameter than the lower piston 15 »the diameter the piston rod is smaller than the lower piston

A cylindrical main valve is slidably housed in the lower cylinder 13. In this main valve 19 is in turn the lower piston 15 is displaceable. The bottom 20 of the lower Piston 15 is directed towards chisel 17. The lower Part 20 has a smaller diameter than the lower piston 15. The section between the lower piston 15 and the lower part 20 is an even smaller part 21 in diameter. Between this part 21 with the small diameter and the inside of the main valve 19 is the oil chamber 22. A conical section 23 extends from the upper end of the smaller diameter part to the lower end of the lower piston 15th

The upper circumference of the main valve 19 forms a in the middle Cylinder 25 fitted valve piston 24.

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On the inner circumference of the lower cylinder 13 is located Circumferential groove 26 on the outside of the main valve 19 in the lowest pitch, an oil outlet channel 27 in the lower cylinder is connected to the circumferential groove 26.

In a part on the circumference of the main valve 19, several connecting channels 28 are formed. The circumferential groove 29 », which coincides with the communication channels when the main valve 19 is in the lowest position, is located on the inner circumference of the lower cylinder. At the bottom of the lower cylinder 13, a sleeve 31 is firmly fitted. In this sleeve 31, the lower end 20 of the lower piston 15 is displaceable. The upper end of the sleeve 31 also receives the lower end of the main valve 19. An annular projection is located on the inside at the upper end of the sleeve 31. The lower end of the lowered main valve 19 closes the circumferential groove 26 from the oil chamber 22.

The chisel 17 carries a flange 32. The upper portion of the The flange 32 is displaceable in the sleeve 34, which is fixed in the screw cylinder 33 at the lower end of the base body 11 is fitted. The chisel holder 16 is on the screw cylinder 33 screwed. The inwardly projecting edge 35 at the lower end of the chisel holder 16 takes the flange 32 of the chisel 17 and prevents it from falling out.

The grip cap 37 is fastened on top of the base body 11. The sleeve sits in a longitudinal bore in the center of the cap 37 The sleeve 38 has a circumferential groove 39ο concentrically below

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is the valve channel 40 with a smaller diameter. The valve channel 40 stands with the inside of the upper cylinder 12 in Link.

The circumferential groove 41 is formed in the longitudinal bore of the handle cap, which surrounds the sleeve 38 on the outside. The two circumferential grooves 41 and 39 stand with the connecting channel 42 in the bush 38 in connection.

In the sleeve 38, the limiting valve 43 is displaceable and closes the valve channel 40 from above. A spring 44 'which presses the valve 43 against the valve channel 40 is between the valve receiver in the cap 37 and the recessed bore 47 of the limiting valve 43 is arranged.

Because the slender shaft 46 at the lower end of the limiting valve protrudes from the valve channel 40 into the upper cylinder 12, the Limiting valve 43 lifted from valve seat 40 when upper piston 14 goes up. In addition, the connecting channel 48 in the shaft 46 of the limiting channel holds the pressure between equal to the upper cylinder 12 and the recessed bore 47 of the relief valve.

In the upper half of the wall of the base body 11 is a longitudinal connection channel 49 molded. At the top it is connected to the circumferential groove 41 via the connecting channel 50. Below the connecting channel 49 leads to the opening 51 at the lower end in the central cylinder 25.

An opening 52 leads on the inside of the upper cylinder 12 to connection channel 49.

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Am another connection channel 53 in cfe? upper half of the wall of the base body 11 is with the opening 54 in the upper cylinder 12 in connection. Its lower end leads to the opening 56 in the chamber 55 between the lower cylinder 13 and the middle one Cylinder 25.

An edge 62 projects inwardly between the chamber 55 and the central cylinder 25.

An air line 58 is connected to an opening 57 in the upper cylinder 12 which leads to a steel cylinder for compressed gas, e.g. air, nitrogen or the like. The check valve 60 and the reducing valve 61 are arranged in the air line and prevent backflow from opening 57 to steel bottle 59.

The pipeline leads from the oil outlet channel 27 to the oil tank. The pipeline to the oil inlet channel 30 is located at the outlet opening of a hydraulic pump. There is a suitable one in the oil line Control valve for any change in the hydraulic pressure generated from the oil inlet opening 30 in the oil chamber 22.

The illustration according to the drawing shows the oil chamber 22 without hydraulic pressure. Is now on the reducing valve 61 Pressurized gas is supplied to the upper chamber in the upper cylinder 12, so this acts on the upper piston 14 and pushes it downwards. This also causes the piston rod 18, the lower piston 15 and the lower end 20 lowered, with the lower end 20 presses the chisel 17 downwards. Part of the compressed gas then passes through the opening 54, the connection channel 53 and the

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Opening 56 into the chamber 55 and acts on the underside of the upper piston 14. However, since the effective pressure area of the The bottom of piston 14 is smaller than that on the top, the piston is pushed down.

Through the opening 52, the connecting channel 4S and the opening Furthermore, some of the pressurized gas reaches the underside of the central cylinder 25 and acts on the lower side of the valve piston of the main valve 19. However, since the gas pressure of the chamber 55 increases the main valve 19 and the top of the piston 24 acts and whose pressure area is larger, the main valve 19 is in the lowest position lowered.

Although the gas pressure through the opening 52, the connecting channel 49 and the connecting channel 50 on the circumferential groove 41, the Connecting channel 42 and the circumferential channel 39 arrives, there the pressure at the top and bottom of the relief valve 43 is equal to that in the upper chamber in the upper cylinder 12 is held, the connecting channel 48, the channel of the valve 43, closed under the action of the spring 44.

By actuating the control valve, oil reaches the oil inlet duct 30. When the hydraulic pressure is greater than the gas pressure in the upper chamber of the upper cylinder 12, the oil enters the oil chamber 22, through the circumferential groove 29 and the connecting channel 28. and pushes the lower piston 15 upwards. The piston rod 18 and the upper piston 14 connected to the lower piston 15 one piece are also brought up.

When the top of the upper piston 14 is over the openings 52, 54, 57, the gas in the upper cylinder 12 is compressed and its pressure increases. Since the limitation valve 43 to the top and is connected below, the valve channel 40 is through the

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Spring 44 held closed.

If the upper piston continues to go up and the pressure in the upper chamber of the upper cylinder 12 is quite high, The top of the upper piston 14 pushes the stem 46 of the relief valve upward, causing the relief valve is lifted from the valve channel 40. This allows the high pressure gas in the upper chamber of the cylinder 12 through the valve channel 40, the circumferential groove 39, the connection channel 50, the connection channel 49 and the opening 51 flow and press the lower side of the piston 24 of the main valve 19.

Since thereby the gas pressure in the chamber 55 and the associated goes down the upper chamber in the middle cylinder 25, the piston 24 and the main valve 19 are raised quickly. The lower The end of the main valve 19 becomes the annular projection -36 the sleeve 31 is pulled out and the oil chamber 22 with the circumferential groove tied together. The connecting channel 28 of the main valve 19 moves over the circumferential groove 29 and closes the oil chamber 22 and the oil inlet passage 30.

As a result, the lower piston 15 is no longer driven by the hydraulic one Pressure is pushed upwards and the upper piston 14, the piston rod 18, the lower piston 15 are pushed by the Top of the upper piston 14 acting high pressure gas driven down very quickly, with the lower end 20 on the chisel 17 hits.

The oil chamber 20 is made smaller by the descending lower piston and the oil returns through the circumferential groove 26 and the oil outlet passage 27 back into the oil tank. When the top of the upper piston 14 is below the openings 52,54,57

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the pressure in the upper cylinder 12 returns to its constant value. The relief valve returns to its original position and the valve channel 40 is closed. Since the gas pressure in the middle cylinder 25 goes back to the original value the main valve 19 is lowered and its lower end goes onto the annular projection 36. By switching off the Oil chamber 22 and the circumferential groove 26, the connecting channel of the main valve 19 is connected to the circumferential groove 29.

If when opening the control valve in the oil line to the oil inlet channel 30 is fed to this oil, the process described above is repeated and the upper piston 14, the piston rod and the lower piston 15 move up and down, the lower one The end of 20 hits the chisel 17 and does the desired job Impact work.

During this process, the gas only passes between the upper and lower sections of the upper cylinder 12, im middle cylinder 25 and the chamber 55 back and forth. In contrast to known impact tools, no air is expelled. so that no exhaust noise can arise. aside from that the gas consumption is very low, so that a gas cylinder of low Kgacity the constant gas pressure despite small leaks during can maintain operation without the need for a compressor.

In contrast, the striking tool according to the invention requires a -hydraulic pump. However, since the most diverse machines are already equipped with hydraulic pumps, this can impact tool according to the invention readily connected to this will.

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3s is the lowest possible flow resistance for the oil strive so that the oil in the oil chamber 22 can escape quickly and the upper piston 14 can go down just as quickly. Therefore, the circumferential groove 26, the oil outlet channel 27 and the oil line between the oil outlet channel and the oil tank are as possible to make great. The main valve 19 must be raised quickly by the high pressure gas, including the entire lower environment of the Oil chamber must be connected to the circumferential groove 26 immediately. However, if the oil ejection speed is too fast, it can become too Cavitation occur, the parts that come into contact with the oil are damaged and the pressure in the oil chamber during the Output increases.

In the invention, however, the main valve 19 is designed to be cylindrical. Even if the main valve 19 is due to the circumferential groove 26 is raised when the oil chamber 22 is connected to the circumferential groove 26 and the oil of the oil chamber 22 flows into the circumferential groove 26, the speed of the oil flow from the oil chamber 22 to the oil outlet channel 27 can be reduced considerably. A roughening of the inside of the oil outlet channel 27 as a result of cavitation during ejection can thereby be prevented.

As the oil flow rate decreases, it can increase of the oil pressure during discharge can be prevented by the resistance of the pipeline and there is no danger of obstruction of the oil to be discharged when the upper piston 14 and the lower piston 15 go down.

In the exemplary embodiment shown, the main valve 19 is arranged in the base body 11. This main valve 19 can, however can also be provided separately from the base body in the discharge line to the oil chamber.

PATENT LAWYERS

DIpI. Ing. E. Her Dipl. Ing. Ft & Meschlce

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Claims (2)

PATENTANWÄLTE / f Dipl. I. ς. E. Eder \ Dipl. Lvj. K. Schieschi Claims iJ impact tool with a base body with an upper and a lower cylinder, with one piston in each cylinder connected by a piston rod, and one below of the base body arranged chisel, on which the lower piston strikes during the downward movement of the piston through a main valve to open and close the oil inlet channel and the oil outlet passage into the oil chamber in the lower section in the lower cylinder, through a pressurized from the upper one Piston moving limiting valve when it rises, whereby the operating section of the main valve and the limiting valve are assigned to each other so that the main valve Switch off the oil chamber and the oil inlet duct and the oil chamber and connect to the oil outlet passage by the operating portion of the main valve in the upper cylinder, the high pressure gas is supplied when the relief valve is moved under pressure by the upper piston, and the oil chamber and the oil inlet passage are connected and the oil chamber and the oil outlet is shut off while the relief valve is not moved under pressure by the upper piston, and when the oil chamber is in communication with the oil inlet channel, the lower piston being pushed upwards by the pressure of the oil that enters the oil chamber through the oil inlet passage. 2. Impact tool according to claim 1, characterized in that that between the main valve and the underside of the lower piston an oil chamber is formed in which the main valve is cylindrical and slidably fitted between the lower piston and the lower cylinder that the high pressure gas in the upper cylinder acts on the underside of the valve piston, 109850/1080 the relief valve is moved under pressure by the upper piston by moving the valve piston outside of the upper section of the main valve is moved into the middle cylinder, which is located in the base body and that a circumferential groove, which communicates with the oil chamber when the main valve is raised, is molded on the inside of the lower cylinder, outside the lower section of the main valve, after moving to the lowest position, the oil outlet channel with the circumferential groove communicates. PATE NTA N ^{D |} P '· »ng. E _f 10 9 8 5 0/10 8 G.