Piston assembly for door closer
US4019220A · kind A · utility
21Cited by
7References
6Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jan 13, 1976 |
| Grant date | Apr 26, 1977 |
| Priority date | — |
| Expiry date | Jan 13, 1996 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T74/1967
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
Hydraulic door closer apparatus comprises a cylinder and an elongated piston disposed in the cylinder, the piston being made of relatively easily machined material, but having associated with it a rack of harder, wear and impact-resistant material for transmitting forces and motion to and from the piston.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.