US3828308A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Operation indicating device for hydraulic brake system
Assignee: Toyota Motor Corp
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Filing: 1972-05-03
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Granted: 1974-08-06
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Expires: 1992-05-03
Abstract
Abstract An indicating device to alarm a vehicle driver of trouble with a hydraulic brake system of a vehicle. The indicating device comprises a closed-type pressure switch to be opened in response to line pressure of a certain value yielded within the hydraulic brake system, an open type brake switch to be closed in response to stepping on a brake pedal of the vehicle after the pressure switch is opened, a relay device including a first coil thereof energized by the closing of the brake switch with the pressure switch remaining extraordinarily closed, and a second coil thereof wound in an opposite direction against the first coil on an iron core on which the first coil is wound so as to operate a bi-stable contact device, and a pilot lamp, located on an instrument panel of the vehicle, being then connected to an electric current source through a key switch of the vehicle and the contact device when both of the pressure and brake switches are closed.
Inventors
- 👤 I Kobayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 03:40
CPC Classifications
B; B60; B60T; B60T17/00; B60T17/18; B60T17/22; B60T17/225
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
304 words
A device for indicating troubles within an automobile hydraulic brake system having a master cylinder, wheel brake cylinders and hydraulic braking circuits to connect said master cylinder with said wheel brake cylinders, comprising: an electric source a key switch; a pilot lamp located at a convenient place; contact means for selectively connecting said source to said lamp through said key switch; normally closed pressure switch means disposed within said braking circuits to be opened in response to a pressure value at or over a predetermined one within said braking circuits; brake switch means normally opened and operable with a foot brake pedal on which stepping causes closing of said brake switch means, said closing being conducted after opening of said pressure switch means in normal operation thereof when pressure of said predetermined value is produced within said braking circuits; relay means including a first coil thereof energized by closing of said brake switch means with said pressure switch means remaining extraordinarily closed, a second coil thereof wound in an opposite direction against said first coil on an iron core on which said first coil is wound, and means, including a blocking diode interposed between said first and second coils, for blocking current supply to said second coil through said first coil, solo-energization of said first coil closing said contact means to light said pilot lamp, solo-energization of said second coil opening said contact means to turn off said pilot lamp and energization of both coils at a time with said contact means closed offsetting magnetic power generated respectively by said first and second coils to cause no effect on said contact means so as to let said pilot lamp remain lighted: and bi-stable locking means operated by energization of either of said coils to maintain the closed or open position of said contact means.
Claim 2
Independent Claim
304 words
A device for indicating troubles within an automobile hydraulic brake system having a master cylinder, wheel brake cylinders and hydraulic braking circuits to connect said master cylinder with said wheel brake cylinders, comprising: an electric source a key switch; a pilot lamp located at a convenient place; contact means for selectively connecting said source to said lamp through said key switch; normally closed pressure switch means disposed within said braking circuits to be opened in response to a pressure value at or over a predetermined one within said braking circuits; brake switch means normally opened and operable with a foot brake pedal on which stepping causes closing of said brake switch means, said closing being conducted after opening of said pressure switch means in normal operation thereof when pressure of said predetermined value is produced within said braking circuits; relay means including a first coil thereof energized by closing of said brake switch means with said pressure switch means remaining extraordinarily closed, a second coil thereof wound in an opposite direction against said first coil on an iron core on which said first coil is wound, and means, including a blocking diode interposed between said first and second coils, for blocking current supply to said second coil through said first coil, solo-energization of said first coil closing said contact means to light said pilot lamp, solo-energization of said second coil opening said contact means to turn off said pilot lamp and energization of both coils at a time with said contact means closed offsetting magnetic power generated respectively by said first and second coils to cause no effect on said contact means so as to let said pilot lamp remain lighted: and bi-stable locking means operated by energization of either of said coils to maintain the closed or open position of said contact means.
Claim 3
Dependent Claim
108 words
A device for indicating troubles within an automobile hydraulic brake system as claimed in claim 1, wherein said bi-stable locking means comprises a bed to hold said relay means thereon, an operation member mounted swingably on said bed and attracted by energization of either of said first or second coil, a return spring to return said operation member to its original position upon deenergization of said coils, and a ratchet operated by said operation member between two positions therefor, said ratchet in one position locking the closed position of said contact means and in the other position releasing the lock of the closed position of said contact means.
Claim 4
Dependent Claim
45 words
A device for indicating troubles within an automobile hydraulic brake system as claimed in claim 1, wherein said pilot lamp is connected directly to a starter terminal of said key switch and also to an ignition terminal of said key switch through said contact means.
Claim 5
Dependent Claim
58 words
A device for indicating troubles within an automobile hydraulic brake system as claimed in claim 1, wherein said pilot lamp is connected to an ignition terminal of said key switch through said contact means and further to an oil level detecting switch within a reservoir of said master cylinder, said detecting switch being coupled to said ignition terminal.
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) | 1977-08-05 | 1978-02-04 | 1978-08-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-05 | 1982-02-04 | 1982-08-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-05 | 1986-02-04 | 1986-08-06 | $7700.00 | Window Closed / Lapsed |