Brake booster with compressible air valve for braking speed of application enhancement
US6209442A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 16, 1999 |
| Grant date | Apr 3, 2001 |
| Priority date | — |
| Expiry date | Aug 16, 2019 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60T8/3275
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A vacuum brake booster provides a braking speed of application enhancement by increasing the air valve opening when a vehicle operator applies braking force quickly and forcefully. This is accomplished with a two part air valve which is normally expanded axially to a normal length by an internal spring but which may be shortened to open the air valve by a greater amount when the brake pedal input force is sufficient to move the air valve axially against another spring into contact with a shoulder of the power piston. The internal spring has a much higher preload than the other spring so that the booster operates with a fully axially expanded air valve in normal, low force brake activation. Once the air valve axially engages the power piston, however, the increase in air valve opening is immediate and substantial with any further increase in braking force. The air valve has an air valve input element having a pin projecting radially outward into an opening in a side wall of an air valve output element surrounding the air valve input element so as to axially engage a side of the opening to limit expansion of the air valve by the spring and thus define the normal axial length of the a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.