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Title: Fail-safe brake for a vehicle
Claims: What is claimed is: 1. A fail-safe brake for a vehicle having an actuator means and friction-type brake members operative to effect brake action in response to said actuator means applying a force thereon, said actuator means comprising a shaft pilot member, a projection coaxially on said pilot member, a piston member fluid-tightly slidable coaxially about said pilot member for movement toward and away from said projection, a cylindrical member affixed to said piston member and extending therefrom and in fluid-tight sliding relation over said projection and defining a fluid-retaining pocket with said projection and said piston member and being operatively associated with said brake members for forcing said brake members into braking action in response to movement of said piston member toward said projection, a fluid pressure pump and passageway in fluid-flow communication with said pocket for fluid pressurizing said piston member in the direction away from said projection to thereby relieve the braking force on said brake members, spring means operatively associated with said piston member for yieldingly moving said piston member toward said projection when the fluid pressure in said pocket is only a minimum pressure and to thereby effect a fail-safe brake action on said brake members, and an additional member being coaxially slidable on said pilot member and operatively associated with said brake members for effecting brake action in response to selective actuation of said additional member independent of movement of said piston member. 2. The fail-safe brake for a vehicle as claimed in claim 1, wherein said additional member is disposed between said piston member and said brake members and is in contact with said cylindrical member for transmitting force from said spring means to said brake members, and said additional member also being arranged for transmitting force directly to said brake members and independent of the force from said piston member, for a service braking action of the vehicle. 3. The fail-safe brake for a vehicle as claimed in claim 2, wherein said additional member is located to the side of said projection opposite from the location of said piston member and is spaced from said projection to define a fluid pocket with said projection, and an additional fluid passageway extending from said pump and into the latter said fluid pocket to have fluid force on said additional member to effect the service braking action. 4. The fail-safe brake for a vehicle as claimed in claim 1, wherein said additional member is a fluid-actuated piston, and including an additional fluid passageway extending from said pump and into flow communication with said fluid-actuated piston for transmitting force directly to said brake members and independent of the force from said piston member, for a service braking action of the vehicle. 5. The fail-safe brake for a vehicle as claimed in claim 4, wherein said cylindrical member on said piston member is movable therewith and extends over and in fluid-tight contact with said fluid-actuated piston, and said cylindrical member and said fluid-actuated piston having abutting surfaces for transmitting the force of said spring means to said fluid-actuated piston. 6. The fail-safe brake for a vehicle as claimed in claim 4, wherein said both fluid passageways extend in said pilot member, and wherein said cylindrical member on said piston member is movable therewith and extends over and in fluid-tight contact with said fluid-actuated piston, and said cylindrical member and said fluid-actuated piston having abutting surfaces for transmitting the force of said spring means to said fluid-actuated piston. 7. The fail-safe brake for a vehicle as claimed in claim 4, including a fluid-flow valve connected with the first-mentioned fluid passageway for controlling flow of fluid to and from said pocket and thereby selectively control the brake. 8. The fail-safe brake for a vehicle as claimed in claim 7, including an additional fluid-flow valve connected with said additional fluid passageway for controlling flow of fluid to said fluid-actuated piston and thereby selectively actuate the brake. 9. The fail-safe brake for a vehicle as claimed in claim 1, including a casing enclosing the brake members and the actuator means, , and connectors attached with some of said brake members and with said casing for effecting braking action against said casing. 10. The fail-safe brake for a vehicle as claimed in claim 1, including a manually maneuverable control operatively associated with said spring means for overcoming the force of said spring means and thereby manually release said brake. Other info: Inventors: Rach, David T. (Milan, IL, US) Application Number: 597421 Filing Date: 1975-07-21 Publication_date: 1976-08-17 Assignee: J. I. Case Company (Racine, WI) Primary Class(es): 188/170 188/72.3, 188/366, 192/91A Other Classes: US Patent Ref:
Other Refs:
Primary Examiner: Blix, Trygve M. Assistant Examiner: Kazenske, Edward R. Attorney: Hansmann; Arthur J. |
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