# US 9,435,336 B2 · Sealing device for a piston

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- Number: US 9,435,336 B2
- Document ID: US9435336B2
- Status: Granted
- Kind: B2
- Application number: 14/338,518
- Filed: 2014-07-23
- Published: 2015-02-05
- Granted: 2016-09-06
- Earliest claimed: 2013-07-23
- Applicants: Vianney Rabhi
- Inventors: Vianney Rabhi
- Web page: https://patentgrep.com/patent/US9435336B2

## CPC

- F04B 53/143: {Sealing provided on the piston}
- F16J 15/164: {the sealing action depending on movements; pressure difference, temperature or presence of leaking fluid}
- F16J 15/56: Other sealings for reciprocating rods
- F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F)
- F16J: PISTONS {(specially adapted for dampers F16F9/32)}; CYLINDERS; SEALINGS

## Abstract

The sealing device (1) for a piston (2) of which the fixed skirt (5) moves in a cylinder (8) includes a sliding skirt (6) traversed axially by a pressure transmission channel (10) and connected to the fixed skirt (5) by a mechanical inter-skirt connection (7) whilst an extensible continuous segment (9) is interposed in a sealed manner between the skirts (5, 6) and can come into contact with the cylinder (8) when its internal cylindrical segment face (12) is subjected to the pressure of a fluid (36) via the pressure transmission channel (10), a sliding skirt spring (16) tending to bring the skirts (5, 6) closer and to axially compress the extensible continuous segment (9) between the skirts (5, 6).

## Claims

### Claim 1

Sealing device for a piston (1) provided for a piston (2) moving in a cylinder (8) of which one of the ends at least is closed by a fluid chamber (27), said piston (2) comprising at least one piston head (3) which includes at least one fixed skirt (5) and has, on the one hand, a piston support face (4) in order to exert a force on any mechanical, hydraulic or pneumatic transmission means (33) and, on the other hand, a compression face (11) which emerges in the fluid chamber (27) and which can receive the pressure of a fluid (36), characterized in that it comprises:
at least one sliding skirt (6) of cylindrical shape housed in the cylinder (8) with a small clearance, placed in the extension of the piston head (3) on the side of the compression face (11) and in the axis of said head (3), said sliding skirt (6) being connected to said head (3) by a mechanical inter-skirt connection (7) which enables it to move in longitudinal translation with respect to said head (3);
at least one pressure transmission channel (10) arranged inside the sliding skirt (6) and passing right through the latter in the axial direction;
at least one extensible continuous segment (9) of continuous annular form, interposed between the fixed skirt (5) and the sliding skirt (6), and comprising an internal cylindrical segment face (12) subjected to the pressure of the fluid (36) via the pressure transmission channel (10), an external cylindrical segment face (13) capable of coming into contact with the cylinder (8), an axial segment face on the side of the fixed skirt (14) held directly or indirectly in sealed contact with the fixed skirt (5) and an axial segment face on the side of the sliding skirt (15) held directly or indirectly in sealed contact with the sliding skirt (6);
at least one sliding skirt spring (16) which tends to bring the sliding skirt (6) closer to the fixed skirt (5), and to axially compress the extensible continuous segment (9).

### Claim 2 (depends on 1)

Sealing device for a piston according to claim 1, characterized in that the mechanical inter-skirt connection (7) which consists of a mandrel (17) integral with the compression face (11) and co-operating with a mandrel orifice (18) arranged axially in the sliding skirt (6), said mandrel (17) being housed in said orifice (18).

### Claim 3 (depends on 1)

Sealing device for a piston according to claim 1, characterized in that the sliding skirt spring (16) is a resilient washer (19) supported on the one hand on the end of the mandrel (17), and on the other hand on the sliding skirt (6).

### Claim 4 (depends on 1)

Sealing device for a piston according to claim 1, characterized in that at least one floating plate (21) with an external diameter substantially smaller than the internal diameter of the cylinder (8) is directly or indirectly interposed between the extensible continuous segment (9) and the fixed skirt (5) or between said segment (9) and the sliding skirt (6), the axial segment face on the side of the fixed skirt (14) and/or the axial segment face on the side of the sliding skirt (15) being kept in sealed contact with said plate (21) whilst this latter is traversed by at least one axial plate orifice (31) enabling the mechanical inter-skirt connection (7) to pass through said plate (21).

### Claim 5 (depends on 4)

Sealing device for a piston according to claim 4, characterized in that the floating plate (21) includes plate centering means (23) which tend to radially center said plate (21) with respect to the sliding skirt (6) or with respect to the fixed skirt (5), said means (23) being supported directly or indirectly on one or the other of said skirts (5, 6) or on the mechanical inter-skirt connection (7).

### Claim 6 (depends on 4)

Sealing device for a piston according to claim 4, characterized in that the floating plate (21) includes a segment groove (22) which co-operates for radial centering of the extensible continuous segment (9) with respect to the sliding skirt (6) or with respect to the fixed skirt (5).

### Claim 7 (depends on 1)

Sealing device for a piston according to claim 1, characterized in that the fixed skirt (5) includes at least one scraper segment (24) housed in a scraper groove (25) arranged on the external cylindrical surface of said skirt (5).

### Claim 8 (depends on 1)

Sealing device for a piston according to claim 1, characterized in that the external cylindrical segment face (13) includes at least one axial micro-leakage groove (26).

### Claim 9 (depends on 1)

Sealing device for a piston according to claim 1, characterized in that the internal cylindrical segment face (12) co-operates with at least one circular sealing joint (32) made of flexible material in order to directly or indirectly produce a seal with the fixed skirt (5) and/or the sliding skirt (6).

### Claim 10 (depends on 1)

Sealing device for a piston according to claim 1, characterized in that the axial portion of the length of the internal cylindrical segment face (12) which is closest to the fixed skirt (5) has on average a larger diameter than the axial portion of the length of said internal cylindrical face (12) which is closest to the sliding skirt (6) in such a way that the extensible continuous segment (9) is, over all of its axial length, radially less thick and less rigid on the side of the fixed skirt (5) than on the side of the sliding skirt (6), whilst the external cylindrical segment face (13) for its part remains approximately of the same diameter over all the axial length of said segment (9).

### Claim 11 (depends on 1)

Sealing device for a piston according to claim 1, characterized in that at least one extensible continuous unlocking segment (35) of continuous annular form and of which the external diameter is substantially smaller than the internal diameter of the cylinder (8) and which is directly or indirectly interposed between two segment continuous extensible (9), said extensible continuous unlocking segment (35) comprising an internal cylindrical unlocking segment face (37) subjected to the pressure of the fluid (36) via the pressure transmission channel (10), an external cylindrical unlocking segment face (38) which can bring closer together the cylinder (8) and two axial unlocking segment faces (39) each kept directly or indirectly in sealed contact with one of the two extensible continuous segments (9).

### Claim 12 (depends on 11)

Sealing device for a piston according to claim 11, characterized in that the sliding skirt (6) has extensible continuous segment centering means (40) which co-operate with the internal cylindrical segment face (12) in order to center the extensible continuous segment (9) with respect to said skirt (6) and/or unlocking segment centering means (41) which co-operate with the internal cylindrical unlocking segment face (37) in order to center the extensible continuous unlocking segment (35) with respect to said skirt (6).

### Claim 13 (depends on 12)

Sealing device for a piston according to claim 12, characterized in that the extensible continuous segment (9) and/or the extensible continuous unlocking segment (35) is (are) kept approximately centered with respect to the sliding skirt (6) by a centering ring which is itself centered with respect to said skirt (6) by centering ring centering means (49).