Pressure-balanced proportioning valve with vent-controlled bypass
US4908522A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 21, 1988 |
| Grant date | Mar 13, 1990 |
| Priority date | — |
| Expiry date | Nov 21, 2008 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60T11/34
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A proportioning valve (40) is disposed within a stepped bore (13) of a master cylinder (10). The proportioning valve (40) defines with the stepped bore (13) a primary pressure receiving chamber (26) and a secondary pressure receiving chamber (28). The proportioning valve (40) includes a two-part piston (58) which includes a primary piston part (52) and a secondary piston part (54) coupled together by a lost motion coupling (53, 55). The piston parts (52, 54) are biased apart by a spring (78), and a sleeve (43) is disposed about the two-part piston (50). Seals (46, 47, 69) are disposed about the primary piston part (52), sleeve (43) and secondary piston part (54) to define an intermediate vented chamber (90), wherein a vent (19) communicates with a reservoir. Pressure failure within the primary receiving chamber (26) causes the primary piston part (52) to be displaced and close off the vent (19 ) so that fluid pressure is trapped within the intermedaite chamber (90) to prevent the secondary piston part (54) from effecting the metering of fluid flow through an outlet (21).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.