Dual rate valve assembly
US3952993A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 22, 1974 |
| Grant date | Apr 27, 1976 |
| Priority date | — |
| Expiry date | Jul 22, 1994 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60T8/36
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A valve assembly in an air brake truck system which meets minimum response time specifications required by authorities and the maximum response rate required by the wheel lock control system for efficient operation. The valve assembly varies the effective orifice size between the air supply inlet and the outlet to the relay valve. The high minimum specified rate is provided for a short period of time for initial response and the lower maximum rate for efficient operation is provided for the remainder of the stop. The valve assembly has a timing section and a variable orifice section. An initially effective large orifice area is provided by moving the valve from its rest or low rate position with an initial application of control pressure, and passing control pressure through a timing orifice to counterbalance the initially applied pressure in a desired short period of time, thereby permitting the valve to return to its first position which establishes a smaller effective orifice area through which the supply pressure flows. The valve is balanced by suitable balance ports and areas so that the operating conditions of the variable orifice section do not affect the operation of the ti…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.