# US 12,000,490 B2 · Gap seal device

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- Number: US 12,000,490 B2
- Document ID: US12000490B2
- Status: Granted
- Kind: B2
- Application number: 18/019,880
- Filed: 2021-07-22
- Published: 2023-09-14
- Granted: 2024-06-04
- Earliest claimed: 2020-08-07
- Assignees: Hammelmann GmbH
- Applicants: Hammelmann GmbH
- Inventors: Felix Hartmann
- Web page: https://patentgrep.com/patent/US12000490B2

## CPC

- F16J 15/445: {with means for adjusting the clearance}
- F04B 53/14: Pistons, piston-rods or piston-rod connections
- F04B 53/143: {Sealing provided on the piston}
- F16J 1/005: {obtained by assembling several pieces}
- F16J: PISTONS {(specially adapted for dampers F16F9/32)}; CYLINDERS; SEALINGS
- 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)

## Abstract

A gap seal device includes a housing with a fluid-filled guiding chamber and a multi-part piston that is translationally and/or rotationally moveable in the guiding chamber. The piston separates a high-pressure region from a low-pressure region of the guiding chamber. The piston forms an annular gap having a nominal gap width with an inner wall delimiting the guiding chamber. The piston has a stepped rod, a sleeve, which is slipped over a stepped-down region of the rod and which has a blind hole, and a coupling. The stepped-down region of the rod or in a tube portion of the sleeve includes a stiffness change. A gap width of the annular gap that is reduced compared with the nominal gap width can be set in a region radial to the stiffness change by stress-caused expansion of an outside diameter of the tube portion of the sleeve in accordance with the set stressing force.

## Claims

### Claim 1

A gap seal device, comprising:
a housing having a fluid-filled guiding chamber; and
a multi-part piston that is translationally or rotationally moveable in the fluid-filled guiding chamber,
wherein the multi-part piston separates a high-pressure region from a low-pressure region of the fluid-filled guiding chamber,
wherein the multi-part piston forms an annular gap having a nominal gap width with an inner wall delimiting the fluid-filled guiding chamber,
wherein the multi-part piston comprises a stepped rod, a sleeve, and a coupling,
wherein the sleeve is slipped over a stepped-down region of the stepped rod and the sleeve has a blind hole,
wherein the stepped-down region of the stepped rod or a tube portion of the sleeve has at least one stiffness change,
wherein a gap width of the annular gap that is reduced compared to the nominal gap width is settable in a region radial to the at least one stiffness change by stress-induced expansion of an outer diameter of the tube portion of the sleeve as a function of a set stressing force.

### Claim 2 (depends on 1)

The gap seal device of claim 1, wherein the stepped rod is stressable relative to the sleeve.

### Claim 3 (depends on 1)

The gap seal device of claim 1, wherein the stepped rod is stressable via the coupling and the sleeve.

### Claim 4 (depends on 3)

The gap seal device of claim 3, wherein the stepped rod is a hollow rod with a through hole in which a pull rod is accommodated, wherein the pull rod is guided through the through hole of the stepped hollow rod and the stepped hollow rod is stressable by coupling a first end of the pull rod to the coupling and a second end of the pull rod to the sleeve.

### Claim 5 (depends on 4)

The gap seal device of claim 4, wherein the coupling has a blind hole with an internal thread, wherein an external thread at the first end of the pull rod is screwed onto the internal thread and a pressure acting in an axial direction of the pull rod on the stepped hollow rod is settable by rotation about a longitudinal axis of the pull rod.

### Claim 6 (depends on 4)

The gap seal device of claim 4, wherein the sleeve is axially adjustable relative to the pull rod with respect to a longitudinal axis of the pull rod.

### Claim 7 (depends on 1)

The gap seal device of claim 1, wherein the at least one stiffness change is a material recess on the inner circumference of the stepped-down region of the stepped hollow rod.

### Claim 8 (depends on 7)

The gap seal device of claim 7, wherein the material recess is an annular recess.

### Claim 9 (depends on 1)

The gap seal device of claim 1, wherein the stepped rod is a stepped-down solid rod.

### Claim 10 (depends on 9)

The gap seal device of claim 9, wherein the at least one stiffness change is a material recess on an inner circumference of the tube portion of the sleeve.

### Claim 11 (depends on 9)

The gap seal device of claim 9, wherein the stepped rod is integrally formed with the coupling.

### Claim 12 (depends on 9)

The gap seal device of claim 9, wherein the stepped rod has a first end with an external thread and is screwed into an internal thread of the sleeve.

### Claim 13 (depends on 12)

The gap seal device of claim 12, wherein the stepped rod has a second end with an external thread, which is screwed into an internal thread of the coupling.