Patent US3947813A successfully refreshed from Google Patents.
US3947813A
Expired / Lapsed
US
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Master cylinder liquid level alarm
Assignee: Aisin Corp
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Filing: 1974-06-27
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Granted: 1976-03-30
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Expires: 1994-06-27
Abstract
Abstract A liquid level reduction alarm device for a braking liquid reservoir vessel in communication with a brake master cylinder wherein the reservoir is closed at its upper open end by an elastic cover member and an elongated hollow case member is suspended from the cover member into the interior space of the reservoir a magnetically operated reed switch is mounted within the interior of the case member and connected with an alarm circuit including an alarm lamp.
Inventors
- 👤 Hiroshi Uemura
- 👤 Kaoru Tsubouchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:35
CPC Classifications
B; B60; B60T; B60T17/00; B60T17/18; B60T17/22; B60T17/225; B60Q; B60Q11/00; B60T11/00; B60T11/10; B60T11/16; B60T11/22; G; G01; G01F; G01F23/00; G01F23/30; G01F23/64; G01F23/72; G01F23/74
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
70 words
A liquid level reduction alarm device for a braking liquid reservoir vessel kept in liquid communication with a brake master cylinder, said reservoir vessel being closed at its upper open end by an elastic cap member from which a case member is suspended to extend into the interior of the reservoir, said case member receiving a magnetically operated reed switch electrically connected through said cap member to an alarm circuit.
Claim 2
Dependent Claim
70 words
A liquid level reduction alarm device for a braking liquid reservoir vessel kept in liquid communication with a brake master cylinder, said reservoir vessel being closed at its upper open end by an elastic cap member from which a case member is suspended to extend into the interior of the reservoir, said case member receiving a magnetically operated reed switch electrically connected through said cap member to an alarm circuit.
Claim 3
Dependent Claim
41 words
The liquid level reduction alarm device of claim 1, wherein a ring float carrying a permanent magnet is arranged slidably along the case member, the position of the float depending upon the liquid level of oil contained in the reservoir vessel.
Claim 4
Dependent Claim
33 words
The liquid level reduction alarm device of claim 2, wherein a stop means is provided on said case member for engagement with said ring float to prevent excess lowering movement of the float.
Claim 5
Dependent Claim
39 words
The liquid level reduction alarm device of claim 3, wherein said cap member is formed with an opening to allow communication of the chamber defined by said reservoir vessel and said cap member with the exterior of said chamber.
Claim 6
Dependent Claim
28 words
The liquid level reduction alarm device of claim 4, further including a cover member detachably mounted on an outer surface of said cap member for covering said opening.
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) | 1979-03-30 | 1979-09-29 | 1980-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-30 | 1983-09-29 | 1984-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-30 | 1987-09-29 | 1988-03-30 | $7700.00 | Window Closed / Lapsed |