US4932247A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Warning device for the brake fluid of hydraulic brake systems of vehicles
Assignee: Daimler Benz AG
•
Filing: 1988-07-25
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Granted: 1990-06-12
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Expires: 2008-07-25
Abstract
Abstract A warning device for detecting mineral oil impurities in the brake fluid of hydraulic vehicle brake systems is described. The warning device comprises a body which is arranged in the brake fluid and can swell as a result of mineral oil and the change of shape of which indicates the presence of mineral oil impurities. The indication is given particularly as a result of the fact that the change in shape brought about by the swelling causes the opening or closing of an electrical circuit and thereby actuates a visual or acoustic indicator in the dashboard of the vehicle.
Inventors
- 👤 Bruno Gorres
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 11:36
CPC Classifications
B; B60; B60T; B60T17/00; B60T17/18; B60T17/22
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
52 words
Warning device for the brake fluid of hydraulic brake systems of vehicles, wherein in order to detect impurities in the brake fluid as a result of mineral oil, a body which swells in the presence of mineral oil to provide means for triggering a warning signal, is arranged in the brake fluid.
Claim 2
Dependent Claim
52 words
Warning device for the brake fluid of hydraulic brake systems of vehicles, wherein in order to detect impurities in the brake fluid as a result of mineral oil, a body which swells in the presence of mineral oil to provide means for triggering a warning signal, is arranged in the brake fluid.
Claim 3
Dependent Claim
34 words
Warning device according to claim 1, wherin the body is equipped on its surface with a thin metal film strip which tears when the body swells to provide means for breaking an electrical circuit.
Claim 4
Dependent Claim
16 words
Warning device according to claim 2, wherein the body is arranged in a brake fluid reservoir.
Claim 5
Dependent Claim
34 words
Warning device according to claim 1, wherein the body is designed as a hollow cylinder, and wherein electrical contacts which close when the body swells are arranged in the hollow space of the cylinder.
Claim 6
Dependent Claim
16 words
Warning device according to claim 4, wherein the body is arranged in a brake fluid reservoir.
Claim 7
Dependent Claim
43 words
Warning device according to claim 1, wherein the body has a conspicuous color and is covered on its surface with a non-swellable, oil-permeable and visually inconspicuous layer of material which tears when the body swells and which thereby makes the conspicuous color visible.
Claim 8
Dependent Claim
16 words
Warning device according to claim 6, wherein the body is arranged in a brake fluid reservoir.
Claim 9
Dependent Claim
16 words
Warning device according to claim 1, wherein the body is arranged in a brake fluid reservoir.
Claim 10
Dependent Claim
13 words
Warning device according to claim 1, wherein the body consists of natural rubber.
References Cited (Backward Citations)
GB845014A
Cited
GB1100717A
Cited
GB1296858A
Cited
US3970865A
Cited
DE2636607A1
Cited
US4566805A
Cited
EP0205870A1
Cited
WO1986007483A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-06-11 | 1993-12-11 | 1994-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-11 | 1997-12-11 | 1998-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-11 | 2001-12-11 | 2002-06-12 | $7700.00 | Window Closed / Lapsed |