# US 5,702,083 A · Pneumatic cylinder of a pneumatic lever-lift chair, and its assembly process

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- Number: US 5,702,083 A
- Document ID: US5702083A
- Status: Granted
- Kind: A
- Application number: 08/633,317
- Filed: 1996-04-17
- Granted: 1997-12-30
- Earliest claimed: 1996-04-17
- Inventors: Shiang-Hwey Lai
- Web page: https://patentgrep.com/patent/US5702083A

## CPC

- A47C 3/30: with vertically-acting fluid cylinder
- A47C: CHAIRS; SOFAS; BEDS

## Abstract

A pneumatic cylinder for use in a pneumatic lever-lift chair, including a cylindrical casing having an inward bottom flange and a plurality of vertically spaced inside annular flanges, a stop plate mounted inside the cylindrical casing and having a plurality of raised portions at the bottom respectively welded to the inward bottom flange of the cylindrical casing by a spot welding machine, and an inner barrel mounted inside the cylindrical casing and having an outward top flange stopped above the top end of the cylindrical casing and a plurality of vertically spaced annular grooves around the periphery respectively forced into engagement with the inside annular flanges of the cylindrical casing.

## Claims

### Claim 1

A pneumatic cylinder for use in a pneumatic lever-lift chair, and its assembly process, the pneumatic cylinder comprising a cylindrical casing having a top opening, a bottom opening, and an inward bottom flange projecting into said bottom opening, a stop plate mounted within said cylindrical casing and fixedly secured to the inward bottom flange of said cylindrical casing, and an inner barrel mounted inside said cylindrical casing, wherein:
said stop plate has a plurality of raised portions at a bottom side respectively welded to the inward bottom flange of said cylindrical casing;
said cylindrical casing comprises a dent formed around the periphery and stopped above said stop plate, and a plurality of inside annular flanges vertically spaced around the periphery above said dent;
said inner barrel comprises a hollow cylindrical body, an outward top flange stopped above the top opening of said cylindrical casing, a plurality of longitudinal ribs equiangularly spaced around an upper part of said cylindrical body on the outside, a plurality of outside annular grooves vertically spaced around a lower part of said cylindrical body on the outside and defining a plurality of vertically spaced convex portion between each two adjacent outside annular grooves, a bottom flange, and a plurality of longitudinal exhaust holes through the outward top flange and bottom flange of said inner barrel at locations corresponding to said longitudinal ribs, the convex portions and bottom flange of said inner barrel having a respective circularly chamfered bottom edge, the annular grooves of said inner barrel being forced into engagement with the inside annular flanges of said cylindrical casing respectively.

### Claim 2 (depends on 1)

The assembly process of the pneumatic cylinder of claim 1 including the steps of:
(A) putting said stop plate into said cylindrical casing, permitting the raised portions of said stop plate to be disposed in contact with the inward bottom flange of said cylindrical casing;
(B) welding the raised portions of said stop plate to the inward bottom flange of said cylindrical casing by a spot welding machine;
(C) processing a dent around the periphery of said cylindrical casing, permitting said dent to be forced into engagement with the topmost edge of said stop plate; and
(D) inserting said inner barrel into said cylindrical casing and forcing the annular grooves of said inner barrel into engagement with the inside annular flanges of said cylindrical casing.