Safety brake for block and tackle window balance
US7028371B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 25, 2003 |
| Grant date | Apr 18, 2006 |
| Priority date | — |
| Expiry date | Apr 11, 2023 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE05Y2900/106
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
The present invention relates to inertial braking system for spring-loaded devices, such as block and tackle window balances incorporated in single and double hung window assemblies. In one embodiment, a block and tackle window balance includes a translatable block assembly disposed in a track including a pawl pivotally attached to the translatable block assembly. The pawl, in response to a rapid acceleration of the translatable block assembly, rotates about a pivot and frictionally engages the track, thereby wedging the translatable block assembly in the track. In another embodiment, the translatable block assembly includes a cam attached to the pawl and a brake shoe disposed between the cam and a cord seated within a pulley. Rotation of the pawl causes the cam to translate the brake shoe, thereby compressing the cord against the pulley.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.