SEALING GASKET

Abstract: A sealing gasket (1) designed to act between two cylindrical components (2, 3) capable of being displaced telescopically into one another. The gasket is so arranged as to be kept stationary in relation to one of the components (2) by means of an annular flange (4) or similar supporting the gasket. A characteristic feature of the invention is that the gasket (1) comprises two concentric sealing rings (5, 6) arranged at a certain distance from one another and an annular piston (8) arranged in the space (7) between the rings (5, 6). The sealing ring (5) situated closest to the aforementioned first component (2) exhibits a generally rectangular or square cross-section, that is to say boundary surfaces (9, 10) which are cylindrical from the radial viewpoint with a U- or V-shaped annular groove (12) which presses inwards from the surface of the ring facing away from the annular flange (4). The second sealing ring (6), which thus makes sealing contact via a cylindrical boundary surface (15) with the second component (3) which moves relative to the sealing gasket (1), exhibits not only an annular surface (16) which rests against the annular flange (4), but also a lower boundary surface (17) situated between the annular surface and the cylindrical boundary surface (15), said lower boundary surface, when viewed in radial section, approaching the cylindrical boundary surface (15) approximately in the form of a parabola at a sharp point (18). The annular piston (8) generally exhibits a cross-section which is wedge-shaped to the extent that its boundary surface (19) which makes contact with the aforementioned sealing ring (5) is of cylindrical form, whilst its opposite boundary surface (20) which makes contact with the other sealing ring (6) is of curved form which fits the boundary surface (17) of the aforementioned sealing ring (6).

Description: S e a l i ng g a s k e t The present invention relates to a sealing gasket designed to act between two cylindrical components capable of being displaced telescopically into one another, for which purpose the gasket is so arranged as to be kept stationary in relation to one of the components by means of an annular flange or similar supporting the gasket. A gasket of this kind has an application in, for example, hydraulic or pneumatic cylinder/piston assemblies and in gas springs. These often operate in a dirty environment and are subject to stresses resulting from their intensive use, which leads to wear and consequent lack of sealing and malfunctions. The gaskets are often designed in such a way as to permit wear to be compensated for through the adjustment of same, although it is obvious that such adjustments lead to costs being incurred not only as a result o ' f the adjustment operation itself, but also as a result of the stoppages and the associated lost production which may be necessary in order to permit the adjustments to be made. The object of the present invention is to make available a sealing gasket of the kind described by way of introduction which is self—adjusting, a feature which is made possible in that the gasket comprises two concentric sealing rings arranged at a certain distance from one another and an annular piston arranged in the space between the rings, in that the sealing devices situated closest to the aforementioned first component exhibit a generally rectangular or square cross—section, that is to say boundary surfaces which are cylindrical from the radial viewpoint with a ■ U'— or 'V 1 —shaped radial annular groove, which presses inwards from the surface of the ring facing away from the annular flange, in that the second sealing ring, which thus makes sealing contact via a cylindrical boundary surface with the second component which moves relative to the sealing gasket, exhibits not only an annular surface which rests against the annular flange, but also a boundary surface situated between the annular surface and the cylindrical boundary surface which, when viewed in radial section, approaches the cylindrical boundary surface approximately in the form of a parabola at a sharp point, and in that the annular piston generally exhibits a cross—section which is wedge—shaped to the extent that its boundary surface which makes contact with the first sealing ring is of cylindrical form, whilst its opposite boundary surface which makes contact with the second sealing ring is of curved form which fits the boundary surface of said sealing ring. The invention is described below in more detail with reference to the accompanying drawing, in which, in the form of a radial section, Fig. 1 shows one design of the sealing gasket forming a seal against a moving piston rod, and Fig. 2 shows the gasket forming a seal against a moving cylinder. ' The designation 1 is used generally in the drawing to indicate a sealing gasket, and the designations 2 and 3 are used to indicate two cylindrical components which are capable of being displaced telescopically relative to one another. The sealing gasket 1 is kept stationary in relation to the component 2 by the fact that it rests upon an annular flange 4 attached to said component or integrated with it. The sealing gasket comprises two concentric sealing rings 5, 6 so arranged at a certain distance from one another as to provide a space 7 between them, and with an annular piston 8 arranged inside the space 7. The sealing ring 5, which makes contact with the fixed component 2 which is fixed relative to the sealing gasket, exhibits a generally rectangular or square cross—section and has from the radial viewpoint cylindrical boundary surfaces 9, 10, of which the boundary surface 9 makes contact with the corresponding cylindrical surface of the component 2 and makes contact by an annular surface 11 with the annular flange 4. A , , — or 'V 1 —shaped groove 12 presses inwards from the side of the sealing ring 5 facing away from the annular flange 4 and into same, in conjunction with which the edges of the groove 11 are executed as sealing lips 13, 14. The sealing ring 6, which makes contact by a cylindrical boundary surface 15 with the cylindrical component 3 which moves relative to the sealing gasket 1, exhibits a generally wedge—shaped cross—section and makes contact by an annular surface 16 with the annular flange 4. Between the cylindrical boundary surface 15 and the annular surface 16 is a boundary surface 17 which faces towards the sealing ring 5 and which, when viewed in radial section, approaches the cylindrical boundary surface 15 in the form of a parabola at a sharp point 18. It may be pointed out that the aforementioned parabolic form is not entirely critical, but rather that the surface shall curve back towards the surface 15 at a rate which is more than linear. The annular . piston 8 exhibits a generally wedge—shaped cross—section with a blunt tip facing towards the space 7. The surface 19 of the annular piston 8 which makes contact with the cylindrical surface 10 of the sealing ring 5 is cylindrical, whilst its opposite boundary surface 20 has a form such that it makes contact with the surface 17 of the sealing ring 6. The sealing gasket 1 in accordance with the invention functions in the following manner: the pressure generated by gas or fluid against which the sealing gasket is required to provide a seal causes the groove 12 to expand so that a good seal is afforded by the lips 13, 14 against the fixed component 2 or against the annular piston 8. The latter is forced by the aforementioned pressure into the space 7, which is preferably vented via a channel 21 through the annular flange 4, and in this way forces the sealing lip of the sealing ring 6 at the point 18 against the moving component 3 in such a way that a good seal is produced here, too. The movement of the moving component 3 will cause the sealing ring 6 to wear, although this wear is compensated for automatically by the annular piston being forced further into the space 7 by the pressure. What is achieved in this way is that the sealing gasket will automatically compensate for wear so that a seal of consistent quality is achieved.

Claims: Pa t e n t C l a i m s 1. A sealing gasket (1) designed to act between two cylindrical components (2, 3) capable of being displaced telescopically- into one another, for which purpose the gasket is so arranged as to be kept stationary in relation to one of the components (2) by means of an annular flange (4) or similar supporting the gasket, c h a r a c t e r i z e d in that the gasket (1) comprises two concentric sealing rings (5, 6) arranged at a certain distance from one another and an annular piston (8) arranged in the space (7) between the rings (5, 6), in that the sealing ring (5) situated closest to the aforementioned first component (2) exhibits a generally rectangular or square cross—section, that is to say boundary surfaces (9, 10) which are cylindrical from the radial viewpoint with a 'U'— or 'V'—shaped annular groove (12) which presses inwards from the surface of the ring facing away from the annular flange (4), in that the second sealing ring (ό), which thus makes sealing contact via a cylindrical ' boundary surface (15) with the second component (3) which moves relative to the sealing gasket (1), exhibits- not only an annular surface (16) which rests against the annular flange (4), but also a boundary surface (17) situated between the annular surface (16) and the cylindrical boundary surface (15) and facing towards the sealing ring (5), said boundary surface, when viewed in radial section, approaching the cylindrical boundary surface (15) approximately in the form of a parabola at a sharp point (18), and in that the annular piston (8) generally exhibits a cross—section which is wedge—shaped to the extent that its boundary surface (19) which makes contact with ( the aforementioned sealing ring (5) is of cylindrical form, whilst its opposite boundary surface (20) which makes contact with the other sealing ring (6) is of curved form which fits the boundary surface (17) of the aforementioned sealing ring (6). 2. A sealing gasket in accordance with Patent Claim 1, c h ar — a c t e r i z e d in that the sealing rings (5, 6) are made of an elastic material, and in that the annular piston (8) is made of a rigid material.

Inventors: KALLER SIGURD, KALLER, SIGURD
Applicants: KALLER SIGURD, KALLER, SIGURD
Application year: 1986
Main classification: F16J15
IPC codes: F16J15