Patent US3818705A successfully refreshed from Google Patents.
US3818705A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Power boost device
Assignee: Bendix GmbH
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Filing: 1973-03-16
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Granted: 1974-06-25
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Expires: 1993-03-16
Abstract
Abstract A power boost device for a split braking system for an agricultural tractor, comprising a servomotor and a servo valve. The valve housing is provided with an inlet port, an output port and an exhaust port. The spool valve, movable in the valve housing, includes a central bore and radial passages to selectively communicate the inlet port and the exhaust port with a work port connected to the working chamber of the servomotor. An output piston is located in said working chamber and comprises a plunger projecting into an enclosed control chamber. Into said control chamber are also projecting two input plungers respectively connected to independent brake pedals. The control chamber is connected to a cavity located at one end of the servo valve housing, in which is slidably mounted the end of the spool valve. The output piston pressurizes a brake chamber connected to two separated braking systems through the intermediary of two control valves independently actuated by the brake pedals.
Inventors
- 👤 A Thomas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:29
CPC Classifications
B; B62; B62D; B62D11/00; B62D11/02; B62D11/06; B62D11/08; B60; B60T; B60T13/00; B60T13/10; B60T13/12
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
196 words
In a power boost mechanism for a system having a multiplicity of circuits, housing means defining a working chamber and a control chamber therewithin, a piston slidably mounted in said working chamber, pressure generating means actuated by said piston, working passage means connecting said pressure generating means to each of said circuits, valve means responsive to the hydraulic pressure level in said control chamber to shift from a released position venting said working chamber to an actuator position communicating successively higher fluid pressure levels into said working chamber as said valve means is shifted from said released position, an output plunger operatively connected to said piston and slidably received within said control chamber, operator-actuated means including at least two input plungers slidably received within said control chamber, the hydraulic pressure level in said control chamber varying as a function of the displacements of said plungers within said control chamber from their rest position, and a working valve in each of said working passage means, each of said input plungers cooperating with a corresponding one of said working valves to thereby open said corresponding working valve upon shifting of the corresponding input plunger from its rest position.
Claim 2
Dependent Claim
196 words
In a power boost mechanism for a system having a multiplicity of circuits, housing means defining a working chamber and a control chamber therewithin, a piston slidably mounted in said working chamber, pressure generating means actuated by said piston, working passage means connecting said pressure generating means to each of said circuits, valve means responsive to the hydraulic pressure level in said control chamber to shift from a released position venting said working chamber to an actuator position communicating successively higher fluid pressure levels into said working chamber as said valve means is shifted from said released position, an output plunger operatively connected to said piston and slidably received within said control chamber, operator-actuated means including at least two input plungers slidably received within said control chamber, the hydraulic pressure level in said control chamber varying as a function of the displacements of said plungers within said control chamber from their rest position, and a working valve in each of said working passage means, each of said input plungers cooperating with a corresponding one of said working valves to thereby open said corresponding working valve upon shifting of the corresponding input plunger from its rest position.
Claim 3
Dependent Claim
30 words
The invention of claim 1: said input plungers engaging said output plunger to permit manual actuation of said piston upon failure of the hydraulic pressure level in said control chamber.
Claim 4
Dependent Claim
37 words
The invention of claim 1: said input plungers having a greater transverse cross-sectional area than that of the output plunger, whereby the stroke of the output plunger is proportionally more than the stroke of the input plunger.
Claim 5
Dependent Claim
13 words
The invention of claim 3: said input plungers having equal transverse cross-sectional areas.
Claim 6
Dependent Claim
41 words
The invention of claim 1; and relief valve means responsive to the pressure differential between the control chamber and the working chamber to vent the control chamber when said pressure differential between the control and working chambers exceeds a predetermined amount.
Claim 7
Dependent Claim
44 words
The invention of claim 1: said working chamber being defined between one face of said piston and a portion of said housing, said pressure generating means including a pressure chamber defined between the other face of said piston and another portion of said housing.
Claim 8
Dependent Claim
63 words
The invention of claim 6: resilient means yieldably urging said piston toward a rest position, refill passage means communicating said working chamber with said pressure chamber, and refill valve means permitting communication through the refill passage means when the piston is disposed in the rest position, but terminating communication through said refill passage means when the piston moves away from the rest position.
Claim 9
Dependent Claim
54 words
The invention of claim 1: said working valve comprising a valve housing, a valve seat in said valve housing, a valve element resiliently urged toward said valve seat, a fixed support, a rod member slidably mounted on said fixed support, and a mechanical linkage between said rod member and one of the input plungers.
Claim 10
Dependent Claim
18 words
The invention of claim 8: said valve housing and said fixed support being integral with said housing means.
Claim 11
Dependent Claim
35 words
The invention of claim 1: a partition within said housing means separating the working chamber from the control chamber, an aperture in said partition, said output plunger extending through said aperture into said contrOl chamber.
Claim 12
Dependent Claim
24 words
The invention of claim 10; and resilient means normally urging said piston toward a rest position wherein said output plunger abuts said input plungers.
Claim 13
Dependent Claim
81 words
The invention of claim 11; and a compensating passage communicating said working chamber to said control chamber, a compensating valve controlling communication through said compensating passage, said compensating valve including a valve member actuated by the output plunger and a valve seat located in said compensating passage, said compensating valve being open when said output plunger is in said rest position, said compensating valve being closed when the displacement of said output plunger from said rest position reaches a predetermined value.
Claim 14
Dependent Claim
25 words
The invention of claim 12: said compensating valve consisting of a flat on said output plunger cooperating with an annular seal located around said aperture.
Claim 15
Dependent Claim
120 words
The invention of claim 1: said housing means defining a bore therewithin having an inlet port communicating said bore with a fluid pressure source, an outlet port, and a return port communicated to a fluid reservoir, and means communicating the bore to the working chamber, said valve means being a spool valve slidable in said bore having a reaction surface on one end thereof, said reaction surface being exposed to the fluid pressure level in said control chamber to shift said spool valve to control communication between said ports and to said working chamber to develop fluid pressure in the working chamber when a brake application is effected, and spring means yieldably urging said spool valve to a released position.
Claim 16
Dependent Claim
65 words
The invention of claim 14: said spool valve having a reaction area opposing said reaction surface, said reaction area being communicated to said working chamber whereby the spool valve is shifted against the force of said spring means when the fluid pressure level in the control chamber exceeds the fluid pressure level in the working chamber by an amount necessary to overcome said spring means.
Claim 17
Dependent Claim
55 words
The invention of claim 15; and relief valve means communicating said control chamber with the working chamber when the pressure level in the control chamber exceeds the pressure level in the working chamber by a predetermined amount substantially higher than the pressure differential between the control and working chamber required to overcome said spring means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-24 | 1977-12-24 | 1978-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-24 | 1981-12-24 | 1982-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-24 | 1985-12-24 | 1986-06-25 | $7700.00 | Window Closed / Lapsed |