# US 4,394,787 A · Hydraulic door closer construction

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- Number: US 4,394,787 A
- Document ID: US4394787A
- Status: Granted
- Kind: A
- Application number: 05/928,403
- Filed: 1978-07-27
- Granted: 1983-07-26
- Earliest claimed: 1978-07-27
- Assignees: Dorma Door Controls, Inc.
- Inventors: Sidney Lieberman
- Web page: https://patentgrep.com/patent/US4394787A

## CPC

- E05F 3/102: {with rack-and-pinion transmission between driving shaft and piston within the closer housing}
- E05Y 2900/132: Doors
- E05F: DEVICES FOR MOVING WINGS INTO OPEN OR CLOSED POSITION; CHECKS FOR WINGS; WING FITTINGS NOT OTHERWISE PROVIDED FOR, CONCERNED WITH THE FUNCTIONING OF THE WING
- E05Y: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES E05D AND E05F, RELATING TO CONSTRUCTION ELEMENTS, ELECTRIC CONTROL, POWER SUPPLY, POWER SIGNAL OR TRANSMISSION, USER INTERFACES, MOUNTING OR COUPLING, DETAILS, ACCESSORIES, AUXILIARY OPERATIONS NOT OTHERWISE PROVIDED FOR, APPLICATION THEREOF

## Abstract

A hydraulic door closer is provided with a fluid seal for its output shaft, the seal comprising multiple O-rings disposed side-by-side in an elongated annular chamber.

## Claims

### Claim 1

For use in hydraulic door closer apparatus of the type comprising a housing having a cylinder therein, a piston disposed in said cylinder, rotary output shaft means journalled in said housing, and means mechanically interconnecting said piston and said output shaft for transmitting forces to and from said piston and said output shaft, a fluid seal for said output shaft comprising a cylindrical surface on said shaft adjacent to an end thereof, and an elongated annular chamber surrounding a portion of said surface and having a pair of axially spaced end walls, and a pair of O-ring members disposed side-by-side in said chamber, the axial dimension of said chamber being greater than the combined axial dimension of said O-ring members, so that said O-ring members can adjust themselves axially within said chamber.

### Claim 2 (depends on 1)

Apparatus in accordance with claim 1, and bearing means supporting said output shaft with respect to said housing, a portion of said bearing means defining one end wall of said chamber.

### Claim 3 (depends on 2)

Apparatus in accordance with claim 2, and a packing member adapted to be coupled to said housing and having an internal bore therein, said bearing means being received in said bore, and a lip projecting inwardly from said bore toward said surface of said output shaft, said bore and said lip defining, respectively, said cylindrical outer wall and are end walls of said chamber.

### Claim 4

Hydraulic door closer apparatus comprising a housing having a cylinder therein, a piston disposed in said cylinder, rotary output shaft means journalled in said housing, means mechanically interconnecting said piston and said output shaft for transmitting forces to and from said piston and said output shaft, and fluid seal means for said output shaft, said fluid seal means comprising an elongated annular chamber surrounding said shaft, said chamber having a cylindrical outer wall and axially spaced end walls, and a pair of O-ring members disposed side-by-side in said chamber, the width of said chamber in the axial direction of said shaft means being greater than the combined thickness of said O-ring members, so that said O-ring members can adjust themselves axially within said chamber.

### Claim 5

Hydraulic door closer apparatus comprising a housing having a cylinder therein, a piston disposed in said cylinder, rotary output shaft means journalled in said housing, means mechanically interconnecting said piston and said output shaft for transmitting forces to and from said piston and said output shaft, and fluid seal means for said output shaft, said fluid seal means comprising an elongated annular chamber surrounding said shaft, said chamber having a cylindrical outer wall and axially spaced end walls, and a pair of O-ring members disposed side-by-side in said chamber, the axial dimension of said chamber being greater than the combined axial dimension of said O-ring members, so that said O-ring members are axially movable within said chamber, bearing means supporting said output shaft with respect to said housing, a portion of said bearing means defining one end wall of said chamber, a packing member associated with said housing and having an internal bore therein, said bearing means being received in said bore, and a lip projecting inwardly from said bore toward said surface of said shaft, said bore and said lip defining, respectively, said cylindrical outer wall and one end wall of said chamber.