US3843892A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Operation indicating device for hydraulic brake system
Assignee: Toyota Motor Corp
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Filing: 1973-12-19
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Granted: 1974-10-22
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Expires: 1993-12-19
Abstract
Abstract An indicating device for warning an operator of trouble in a hydraulic brake system of a vehicle. The indicating device comprises a pilot lamp located at a convenient place, a contact device for selectively connecting an electric source to the lamp through a key switch of the vehicle, a pressure switch to be actuated in response to line pressure of a predetermined 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 actuated, and a bistable electromagnetic relay to actuate the contact device. The contact device includes a first and a second fixed contacts permanently magnetized, the first contact being insulated and the second contact being connected to the pilot lamp, and a magnetizable mobile contact to be engaged with the second contact for selectively connecting the electric source to the pilot lamp. The electromagnetic relay includes a first coil connected at its one end to the electric source across the brake switch and grounded at its other end across the pressure switch and a second coil connected in parallel with the first coil and the pressure switch, the first coil being wound in an opposite direction against the second coil around said mobile contact of the contact device and exerting larger electromagnetic force than that of the second coil.
Inventors
- 👤 I Kobayashi
- 👤 M Noba
- 👤 H Fujimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:56
CPC Classifications
B; B60; B60T; B60T17/00; B60T17/18; B60T17/22
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
325 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 including a first and a second fixed contacts permanently magnetized, said first contact being insulated and said second contact being connected with said lamp, and a magnetizable mobile contact to be engaged with said second contact for selectively connecting said electric source to said lamp through said key switch; pressure switch means disposed within said braking circuits to be actuated 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 brake pedal on which stepping causes closure of said brake switch means, said closure being conducted after the actuation of said pressure switch means in normal operation thereof when pressure of said predetermined value is produced within said braking circuits; and electromagnetic relay means including a first coil connected at its one end to said electric source across said brake switch means and grounded at its other end across said pressure switch means, and a second coil connected in parallel with said first coil and said pressure switch means, said first coil being wound in an opposite direction against said second coil around said mobile contact and producing larger electromagnetic force than that of said second coil, whereby said mobile contact is engaged with said second fixed contact by means of the electromagnetic force exerted from both or one of said coils energized upon the closure of said brake switch means with said pressure switch means remaining extraordinarily inoperative to light said pilot lamp and maintains the engagement with said second contact by the permanent magnetic force of said second contact itself so as to let said pilot lamp remain lighted.
Claim 2
Independent Claim
325 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 including a first and a second fixed contacts permanently magnetized, said first contact being insulated and said second contact being connected with said lamp, and a magnetizable mobile contact to be engaged with said second contact for selectively connecting said electric source to said lamp through said key switch; pressure switch means disposed within said braking circuits to be actuated 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 brake pedal on which stepping causes closure of said brake switch means, said closure being conducted after the actuation of said pressure switch means in normal operation thereof when pressure of said predetermined value is produced within said braking circuits; and electromagnetic relay means including a first coil connected at its one end to said electric source across said brake switch means and grounded at its other end across said pressure switch means, and a second coil connected in parallel with said first coil and said pressure switch means, said first coil being wound in an opposite direction against said second coil around said mobile contact and producing larger electromagnetic force than that of said second coil, whereby said mobile contact is engaged with said second fixed contact by means of the electromagnetic force exerted from both or one of said coils energized upon the closure of said brake switch means with said pressure switch means remaining extraordinarily inoperative to light said pilot lamp and maintains the engagement with said second contact by the permanent magnetic force of said second contact itself so as to let said pilot lamp remain lighted.
Claim 3
Dependent Claim
64 words
An indicating device as claimed in claim 1, wherein said first and second fixed contacts are formed by the opposite ends of two magnetizable elements located at the both poles of a permanent magnet assembled within a casing and said mobile contact is a magnetizable member pivoted at its one end and at its other end positioned between said two elements within said casing.
Claim 4
Dependent Claim
39 words
An indicating device as claimed in claim 1, wherein a resistor is connected in series with said second coil of said relay means to make the electromagnetic force of said second coil less than that of said first coil.
Claim 5
Dependent Claim
79 words
An indicating device as claimed in claim 1, wherein said pressure switch means is a normally closed pressure switch to be opened in response to the pressure of said predetermined value, whereby said mobile contact of said contact means is engaged with said second fixed contact by means of the electromagnetic force exerted from both of said coils energized upon the closure of said brake switch means with said pressure switch remaining extraordinarily closed to light said pilot lamp.
Claim 6
Dependent Claim
78 words
An indicating device as claimed in claim 1, wherein said pressure switch means is a normally open pressure switch to be closed in response to the pressure of said predetermined value, whereby said mobile contact of said contact means is engaged with said second fixed contact by means of the electromagnetic force exerted from said second coil energized upon the closure of said brake switch means with said pressure switch remaining extraordinarily opened to light said pilot lamp.
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) | 1977-10-21 | 1978-04-22 | 1978-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-21 | 1982-04-22 | 1982-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-21 | 1986-04-22 | 1986-10-22 | $7700.00 | Window Closed / Lapsed |