US3567884A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Safety signal for braking systems
Assignee: Old Carco LLC
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Filing: 1965-12-23
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Granted: 1971-03-02
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Expires: 1985-12-23
Abstract
Abstract A warning apparatus composed of a signal device and a hydraulic differential pressure responsive control for indicating damage or failure of one of the brake circuits in a dual brake system. The control includes a housing having a bore in which is slidably disposed a piston having end portions in sealing engagement with the bore and an intermediate portion of reduced diameter, the piston ends, reduced diameter portion, and the bore forming a chamber which is at atmospheric pressure throughout operation of the brakes. The housing has passageways at both ends of the piston which enable fluid to flow through the housing and contact the outer faces of the piston. A switch connected in circuit to the signal device is mounted on the housing and has a switch actuating portion which extends into the bore between the piston end portions and in engageable relationship therewith when the piston moves in response to a pressure differential acting thereon. Pressure imbalance due to failure of one of the brake circuits causes the piston to contact the switch actuating portion so as to complete the circuit and actuate the signal device.
Inventors
- 👤 Joseph W Douglas
- 👤 Bernard J Besso
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 19:23
CPC Classifications
B; B60; B60T; B60T17/00; B60T17/18; B60T17/22; B60T17/226; H; H01; H01H; H01H35/00; H01H35/24; H01H35/38
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
310 words
In an automotive vehicle equipped with a front and rear set of brakes and a safety hydraulic brake control system wherein a master cylinder is connected to the front set of brakes by a first brake circuit and to the rear set of brakes by a second brake circuit, a signal means operable for warning of loss of pressure in one of said first and second brake circuits and hydraulic differential pressure responsive control means communicating with said first and second brake circuits which is effective at times to actuate said signal means, said control means comprising a housing having a bore extending longitudinally therein, a piston having spaced piston lands and a portion of reduced diameter between said lands movably disposed in said bore, said reduced diameter portion and inner faces of said lands cooperating with said bore to define a chamber which is at atmospheric pressure throughout operation of the vehicle brakes, a first passageway formed in one end portion of said housing and connected to said first circuit so as to enable hydraulic fluid to flow through said housing and contact the outer face of one of said piston lands, a second passageway formed in the other end portion of said housing and connected to said second brake circuit so as to enable hydraulic fluid to flow through said housing and contact the outer face of the other of said piston lands, sealing means curved by each of said piston lands and engaging the bore, said sealing means permitting hydraulic fluid to contact the outer faces of said lands and preventing hydraulic fluid from building pressure within said chamber, and a switch carried by said housing and having a portion extending into said chamber and positioned between said spaced piston lands so as to be operable by movement of said piston to complete a signal actuating circuit.
Claim 2
Dependent Claim
310 words
In an automotive vehicle equipped with a front and rear set of brakes and a safety hydraulic brake control system wherein a master cylinder is connected to the front set of brakes by a first brake circuit and to the rear set of brakes by a second brake circuit, a signal means operable for warning of loss of pressure in one of said first and second brake circuits and hydraulic differential pressure responsive control means communicating with said first and second brake circuits which is effective at times to actuate said signal means, said control means comprising a housing having a bore extending longitudinally therein, a piston having spaced piston lands and a portion of reduced diameter between said lands movably disposed in said bore, said reduced diameter portion and inner faces of said lands cooperating with said bore to define a chamber which is at atmospheric pressure throughout operation of the vehicle brakes, a first passageway formed in one end portion of said housing and connected to said first circuit so as to enable hydraulic fluid to flow through said housing and contact the outer face of one of said piston lands, a second passageway formed in the other end portion of said housing and connected to said second brake circuit so as to enable hydraulic fluid to flow through said housing and contact the outer face of the other of said piston lands, sealing means curved by each of said piston lands and engaging the bore, said sealing means permitting hydraulic fluid to contact the outer faces of said lands and preventing hydraulic fluid from building pressure within said chamber, and a switch carried by said housing and having a portion extending into said chamber and positioned between said spaced piston lands so as to be operable by movement of said piston to complete a signal actuating circuit.
Claim 3
Dependent Claim
350 words
In an automotive vehicle equipped with a front and rear set of brakes and a safety hydraulic brake control system wherein a master cylinder is connected to the front set of brakes by a first brake circuit and to the rear set of brAkes by a second brake circuit, a signal means operable for warning of loss of pressure in one of said first and second brake circuits and hydraulic differential pressure responsive control means communicating with said first and second brake circuits which is effective at times to actuate said signal means, said control means comprising a housing having a bore extending longitudinally therein, a piston having spaced piston lands and a portion of reduced diameter between said lands movable disposed in said bore, said reduced diameter portion and inner faces of said lands cooperating with said bore to define a chamber which is at atmospheric pressure throughout operation of the vehicle brakes, an insert seal in each end portion of said bore, said insert seals and said spaced piston lands cooperating to form first and second fluid cavities adjacent the opposite end portions of said bore, a first passageway formed in one end portion of said housing and connected to said first circuit so as to enable hydraulic fluid to flow through said first cavity and exert pressure on one of said piston lands, a second passageway formed in the other end portion of said housing and connected to said second brake circuit so as to enable hydraulic fluid to flow through said second cavity and exert pressure on the other of said piston lands, sealing means carried by each of said piston lands and engaging the bore, said sealing means permitting hydraulic fluid to contact the outer faces of said lands and preventing hydraulic fluid from building pressure within said chamber, and a switch connected to said signal means which is operable by said piston, said switch portion extending into said chamber and positioned between said spaced piston lands so as to be in engageable relationship with one of said piston lands upon movement of said piston.
Claim 4
Dependent Claim
350 words
In an automotive vehicle equipped with a front and rear set of brakes and a safety hydraulic brake control system wherein a master cylinder is connected to the front set of brakes by a first brake circuit and to the rear set of brAkes by a second brake circuit, a signal means operable for warning of loss of pressure in one of said first and second brake circuits and hydraulic differential pressure responsive control means communicating with said first and second brake circuits which is effective at times to actuate said signal means, said control means comprising a housing having a bore extending longitudinally therein, a piston having spaced piston lands and a portion of reduced diameter between said lands movable disposed in said bore, said reduced diameter portion and inner faces of said lands cooperating with said bore to define a chamber which is at atmospheric pressure throughout operation of the vehicle brakes, an insert seal in each end portion of said bore, said insert seals and said spaced piston lands cooperating to form first and second fluid cavities adjacent the opposite end portions of said bore, a first passageway formed in one end portion of said housing and connected to said first circuit so as to enable hydraulic fluid to flow through said first cavity and exert pressure on one of said piston lands, a second passageway formed in the other end portion of said housing and connected to said second brake circuit so as to enable hydraulic fluid to flow through said second cavity and exert pressure on the other of said piston lands, sealing means carried by each of said piston lands and engaging the bore, said sealing means permitting hydraulic fluid to contact the outer faces of said lands and preventing hydraulic fluid from building pressure within said chamber, and a switch connected to said signal means which is operable by said piston, said switch portion extending into said chamber and positioned between said spaced piston lands so as to be in engageable relationship with one of said piston lands upon movement of said piston.
Claim 5
Dependent Claim
77 words
A control means as set forth in claim 13 wherein each of said insert seals is a generally cylindrical member having at least a portion of its peripheral surface in sealing engagement with the surface of said bore and wherein at least one of said insert seals has an axially extending conduit formed therethrough, said conduit having one end in communication with one of said cavities and its opposite end in communication with a cooperating brake circuit.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |