Control apparatus for doors
US4976065A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 20, 1989 |
| Grant date | Dec 11, 1990 |
| Priority date | — |
| Expiry date | Nov 20, 2009 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE05Y2900/132
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A speed control apparatus for controlling the rate of motion of a door is disclosed which includes a shaft connected with the door by a gear train for causing rotation of the shaft at a preselected relative rate of rotation related to the rate of motion of the door by a preselected ratio, a braking assembly including a brake drum spaced from the shaft and first and second brake shoes pivotably connected at one end thereof with a carrying member attached to the shaft and having a single biasing spring adjustably connected between the other ends thereof, the brake shoes having a contact surface made of a non-asbestos friction material for contacting the brake drum when a selected rate of rotation of the shaft is exceeded, and an improved housing which is more efficiently sealable against invasion of moisture into the housing and the escape of lubricants from the housing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.