DE2504869A1 - SEAL FOR USE ON A HYDRAULICALLY DRIVEN IMPACT TOOL - Google Patents

Description

PATENTANWALT BODE - 4033 HOScL POST BOX 1140 TELEFCK 02102-60001 -TELEX 8585166

Rl-521+

DOBSON PARK INDUSTRIES LIMITED: Dobson Park House, Colwlck Industrial Estate, Colwick, Nottingham NGM-2BX, England

Seal for use on a hydraulically powered

Impact tool

The invention relates to a seal for use on a hydraulically driven percussion tool, the percussion piston of which is arranged to be longitudinally displaceable in a working cylinder and on the backward stroke under the action of a hydraulic pressure medium in a gas-filled, sealed pressure chamber immersed and on the forward stroke by the during the The backward stroke of compressed gas is powered “with a Sealing ring around the percussion piston in an annular recess in the cylinder wall between the with Gas-filled pressure chamber and the hydraulically acted upon working chamber is arranged.

Particularly high demands are made of such a seal on such an impact tool because it is in two opposite directions must alternately seal very high pressures, with an added complication that the seal to be sealed Medium in one direction a liquid and in the other direction a gas under high pressure is. Conventional sealing rings withstand these stresses only for a short time and wear out quickly. The result is"

009814/0287

PATENTANWALT BODE 4033 HOSEL POST BOX 1140 TELEPHONE W 02-60001 - TELtX, 8585166

that after a relatively short period of operation, hydraulic fluid enters the gas-filled pressure chamber, where- .... is impaired by the function of the striking tool. Gas bubbles can also enter the hydraulic fluid, open working chamber.

It is therefore the object of the invention to create a seal which can better withstand these special stresses and .-. · remains functional longer.

The invention relates to a seal for use on a hydraulically driven percussion tool, its percussion piston Arranged longitudinally displaceable in a working cylinder is and during the backward stroke under the action of a hydraulic pressure medium in a gas-filled, sealed pressure chamber immersed and on the forward stroke by the during the The backward stroke of the compressed gas is driven, with a sealing ring that wraps around the percussion piston in an annular shape Recess in the cylinder wall between the with. Gas-filled pressure chamber and the hydraulically pressurized one Working chamber is arranged, this seal being characterized in that the sealing ring is made of elastic material consists and by a spring ring and one arranged for even load distribution between the spring ring.und the sealing ring The support ring is so loaded that it has a sealing effect in both directions of movement of the percussion piston.

In the design of the seal according to the invention, the has elastic material existing sealing ring in a particularly advantageous manner in both opposite directions the same Sealing effect and is created by the spring ring in cooperation with the support ring in the manner of a spring loaded stuffing box

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PATENT ADVERTISER BODE · 4033 HOStL - POST BOX Π4ϋ. TELEPHONE 02; 02-60Ö01 TELEX 8585166

constantly adjusted. Extensive tests have shown that with a seal according to the invention with better Sealing effect a significantly longer service life can be achieved.

The spring ring is expediently designed to be corrugated in the circumferential direction. This results in large adjustment forces over a relatively large adjustment path. Such a corrugated spring ring can, for example, be made of carbon-rich Spring steel with a circular cross-section, for example made of so-called piano wire, which is bent into a ring is and is bent up and down in the circumferential direction at certain intervals in such a way that oppositely directed result in resilient bends. The spring ring does not need to run continuously in the circumferential direction, but rather can also be divided into several segments or other parts.

The spring ring is expediently held and supported in position by a retaining ring which is attached to the end of the recess forming support shoulder is supported and through which the force acting on the sealing ring with respect to its cross section is centered. As a result, the sealing ring is always applied evenly to the circumference with compressive forces, so that result in the same sealing and wear conditions all around.

In order to give the spring ring the necessary centric hold, the retaining ring has an annular lip that is inserted into the The area of the spring washer reaches in and fixes it.

The sealing ring, which consists of a relatively soft material, must prevent the elastic material from being pushed out sideways

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PATENTANWALT BODE 4033 HOSCL PCSTFACM 1140 TELEPHONE 02102-60001 - TELEX 8585166

be protected as a result of the action of the moving percussion piston. For this reason, protective elements are assigned to the sealing ring, which prevent the elastic material from being pushed out laterally by the action of the moving percussion piston. Two protective rings, which are arranged on both sides of the sealing ring and of which one rests against a support shoulder forming the end of the annular recess and the other rests against the support ring, are expediently used as protective means of this type. These protective rings are made of reinforced elastic material, the hardness of which is considerably greater than that of the material of the sealing ring. This reinforced elastic material of the protective rings is expediently reinforced with textile fibers, preferably nitrile rubber reinforced with cotton fibers. The protective rings on both sides of the sealing ring, which are pressed against the sealing ring from both sides by the action of the spring ring, prevent the material of the sealing ring from being carried along when the piston moves and being pushed out laterally. The radial expansion of the material of the sealing ring under the action of the force of the spring ring, however, do not prevent the safety rings. In order to give the percussion piston the necessary guidance in the area of the seal, it is also provided that the support ring consists of spheroidal graphite cast iron and serves as a slide bearing for the percussion piston. As a result, the piston is properly guided in the area of the seal without excessive wear.

An embodiment of the invention is explained in more detail below with reference to the drawing, in which a section through the Impact tool is shown in the area of the sealing ring.

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PATENTANWALT BODE 4033 HöSEl POST BOX Π4υ TELEPHONE C2102-60001 TELEX 8585166

25Q4869

In the drawing is a percussion piston with the numeral ^ Io denotes which is displaceable in a cylinder from which a chamber 11 is acted upon by a hydraulic pressure medium and another chamber 12 contains air or an inert gas. The percussion piston is on the return stroke driven by the hydraulic pressure medium and thereby compresses the gas located in the closed chamber 12. At a suitable point in time, the pressure in the chamber 11 is relieved by actuating a reversing valve. so that the percussion piston Io is propelled forward by the compressed gas in the chamber 12 and not on one Chisel shown or another suitable tool hits.

A seal 13 is provided to produce a liquid-tight and gas-tight seal during the reciprocating movement of the piston Io between the chambers 11 and 12. The seal 13 has a sealing ring I ¹ + made of elastic material, for example with a hardness of 6o% -7o% Shore. The sealing ring IM- is provided on both sides with protective rings 15 and 16, which prevent the sealing ring 14 from being pushed out to the side and consist, for example, of nitrile rubber reinforced with cotton, which is considerably harder than the material of the sealing ring 14. The protective ring 15 rests on a support shoulder 17 which is arranged at one end of an annular recess 18 located in the cylinder wall, which is used to receive the seal. A support ring 2o rests against the other protective ring 16. The support ring 2o is preferably made of spheroidal graphite cast iron and can also serve as a bearing for the percussion piston Io.

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PATENT ADVERTISER BODE 4033 HOSEL POST BOX 1140 TELEPHONE 02102-60001 TELEX 8585166

A spring ring 21, which is wave-shaped in the circumferential direction, is arranged between the support ring 2o and a retaining ring 22, which rests against a support shoulder 23 which is formed at the other end of the annular recess 18. The retaining ring 2 is expediently made of soft iron and is provided with an integrally formed annular lip 24 which protrudes into the i-area of the spring ring 21 and serves to fix the spring ring in place.

- patent claims -

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Claims (9)

PATENTANWACT BODE - 403a HDSEL- POSTFACH 1140. TELEFON 02.1Og-OOOOl. TELEX 8585166 R 1- -524 Claimsι • 1. Seal for * use on a hydraulically driven one ^ -—- ■ . Impact tool, the impact piston of which is arranged longitudinally displaceably in a working cylinder and, during the return stroke, dips into a gas-filled, sealed pressure chamber under the action of a hydraulic pressure medium and is driven during the forward stroke by the gas compressed during the return stroke, with a sealing ring that surrounds the impact piston is arranged around in an annular recess in the cylinder wall between the gas-filled pressure chamber and the hydraulically acted upon pressure chamber, characterized in that the sealing ring Cl ¹ +) consists of elastic material and is provided with a spring ring (21) and one for evenly distributing the load between the Feden-ing (21) and the sealing ring (14) arranged support ring (2o) is loaded in such a way that it has a sealing effect in both directions of movement of the percussion piston (lo). 2. Seal according to claim I ₉ characterized geke η η ze leans that the spring ring (21) is formed corrugated in the circumferential direction. 3. Seal according to claims 1 and 2, characterized in that the spring ring (21) of one Retaining ring (22) is held and supported in position on a support shoulder forming the end of the recess (18) (23) is supported and through which the on the sealing ring (14) acting force is centralized with respect to its cross-section. 609814/0 2 87. , "_ ₈ _ PATENTANWALT BODE 4033 HÖSEL POST BOX IMO TELEFC ⁴ N 02102-60001 TELEX 8585166 4. Seal according to claims 1-3, characterized that the retaining ring (22) has an annular lip (24) which extends into the region of the The spring ring (21) extends in and fixes it. 5. Seal according to one of claims 1-4, characterized in that the sealing ring (14) Protective means are assigned that prevent the elastic material of the sealing ring (14) from being pushed out to the side. by the action of the moving percussion piston (lo). 6. Seal according to claim 5, characterized that as a means of protection against the pressing out of the elastic material of the sealing ring (14) two protective rings (15, 16) are used, which are arranged on both sides of the sealing ring (14) and of which one (15) on one end of the annular recess (18) forming the support shoulder (17) and the other on the Support ring (2o) is in contact. 7. Seal according to claims 5 and 6, characterized in that the protective rings (15, 16) consist of reinforced elastic material, the hardness of which is considerably greater than the hardness of the material of the sealing ring (14) is. 8. Seal according to claims 5-7, characterized that the reinforced elastic material of the protective rings (15, 16) reinforced with textile fibers Nitrile rubber is. 609814/0287 PATENTANWALT BODE 4033 HOSRL - ⁰ OSTFACH 1140 TEUTON 02102-60001 TELEX 8585166 9. Seal according to one of claims 1 - 8, characterized in that the support ring (2o) consists of spheroidal graphite cast iron and serves as a slide bearing for the percussion piston (lo). II / sch 6098U / 0287 Blank page