Block and tackle balance with integral, non-rotating pulley system
US5737877A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 26, 1996 |
| Grant date | Apr 14, 1998 |
| Priority date | — |
| Expiry date | Jul 26, 2016 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE05Y2900/148
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A block and tackle balance disposed between a jambliner and a window sash includes a spring and a non-rotating pulley system. A head block is disposed on a rod for attaching the balance to the jambliner and securing one end of the spring, and a slide block is disposed at about the midpoint of the rod for securing the other end of the spring. The slide block acts in combination with a base block and a pulley cord, to create the non-rotating pulley system. The slide block and the base block each have at least one cord-receiving channel formed in a raised u-shaped member, for slidably receiving the pulley cord. The base block further includes a bore for securing an end of the pulley cord, and is coupled via the pulley cord to a shoe, which moves in response to movement of the window sash. As the shoe moves, the cord slides within the channels, and the slide block moves toward the base block. The displacement of the slide block relative to the fixed head block, results in a change in the length of the spring such that the spring supports the new position of the window sash.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.