Patent US4004660A successfully refreshed from Google Patents.
US4004660A
Expired / Lapsed
US
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Control system for hydrokinetic brakes
Assignee: British Railways Board
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Filing: 1975-06-27
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Granted: 1977-01-25
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Expires: 1995-06-27
Abstract
Abstract A control system for a hydrokinetic brake has a pressurized working fluid reservoir connected to the hydrokinetic brake by fluid feed and return lines. A regulating valve sets the pressure in the reservoir at a value related to a required braking torque. The inlet pressure of the hydrokinetic brake is maintained at a fixed value lower than the reservoir pressure, for example by an atmosphere vent, during normal braking operation so that the outlet pressure of the brake and hence the braking torque has a direct relationship with the reservoir pressure, irrespective of the rotational speed of the brake.
Inventors
- 👤 Anthony G. L. Shore
- 👤 Kevin S. Preston
- 👤 David A. Churchill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:59
CPC Classifications
F; F16; F16D; F16D57/00; F16D57/005; B; B60; B60T; B60T1/00; B60T1/02; B60T1/08; B60T1/087; B60T13/00; B60T13/10; B60T13/58; B60T13/585; B60T8/00; B60T8/32; B60T8/321; B60T8/3235; F16D57/04
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
170 words
A method for controlling a brake system embodying a hydrokinetic brake of the type having a rotor and a stator together defining a toroid and also having inlet and outlet ports for liquid flowing continually through the brake during brake application from said inlet port to said outlet port, comprising the steps of: maintaining for each desired braking torque an essentially constant flow of said liquid into said inlet port from a liquid reservoir, said essentially constant flow being independent of the speed of rotation of said rotor; conveying said liquid from said outlet port to said liquid reservoir; controlling the braking torque of said brake essentially independently of the speed of rotation of said rotor by setting the pressure acting on said liquid reservoir in accordance with the desired braking torque; maintaining the pressure at said inlet port at a fixed pressure which is lower than the pressure in said reservoir, said fixed pressure being independent of the desired braking torque and the speed of rotation of said rotor.
Claim 2
Independent Claim
170 words
A method for controlling a brake system embodying a hydrokinetic brake of the type having a rotor and a stator together defining a toroid and also having inlet and outlet ports for liquid flowing continually through the brake during brake application from said inlet port to said outlet port, comprising the steps of: maintaining for each desired braking torque an essentially constant flow of said liquid into said inlet port from a liquid reservoir, said essentially constant flow being independent of the speed of rotation of said rotor; conveying said liquid from said outlet port to said liquid reservoir; controlling the braking torque of said brake essentially independently of the speed of rotation of said rotor by setting the pressure acting on said liquid reservoir in accordance with the desired braking torque; maintaining the pressure at said inlet port at a fixed pressure which is lower than the pressure in said reservoir, said fixed pressure being independent of the desired braking torque and the speed of rotation of said rotor.
Claim 3
Dependent Claim
29 words
A method according to claim 1, wherein said liquid is conveyed from said outlet to said reservoir through a closed conduit exhausting to the pressure acting on said reservoir.
Claim 4
Dependent Claim
25 words
A method according to claim 1, wherein said fixed pressure is maintained substantially at the center of said toroid, said fixed pressure being atmospheric pressure.
Claim 5
Dependent Claim
59 words
A method according to claim 1, wherein said brake system further embodies mechanical braking means, further comprising the steps of: comparing the pressure at a point in a line connecting with the interior of said hydrokinetic brake with the pressure in said reservoir; and applying said mechanical braking means when a predetermined ratio is achieved for said compared pressures.
Claim 6
Dependent Claim
34 words
A method according to claim 4, further comprising the step of increasing the braking torque of said mechanical braking means as the ratio of said compared pressures continues to vary beyond said predetermined ratio.
Claim 7
Dependent Claim
168 words
A control system for a hydrokinetic brake, said brake having a rotor and a stator together defining a toroid and also having an inlet port and an outlet port for liquid flowing continually through the brake from said inlet port to said outlet port during brake application, comprising: a liquid reservoir; first means for selectively setting the pressure in said reservoir in accordance with the desired braking torque; second means for conveying liquid at an essentially constant flow rate, in accordance with the pressure selected by said first means, from said reservoir to said inlet port during brake application, said second means conveying liquid at different, substantially constant flow rates for each desired braking torque irrespective of the speed of rotation of said rotor; third means for constantly maintaining the pressure at said inlet port at a fixed pressure which is lower than the pressure in said reservoir during brake application; and fourth means for continually conveying liquid from said outlet port to said reservoir during brake application.
Claim 8
Dependent Claim
168 words
A control system for a hydrokinetic brake, said brake having a rotor and a stator together defining a toroid and also having an inlet port and an outlet port for liquid flowing continually through the brake from said inlet port to said outlet port during brake application, comprising: a liquid reservoir; first means for selectively setting the pressure in said reservoir in accordance with the desired braking torque; second means for conveying liquid at an essentially constant flow rate, in accordance with the pressure selected by said first means, from said reservoir to said inlet port during brake application, said second means conveying liquid at different, substantially constant flow rates for each desired braking torque irrespective of the speed of rotation of said rotor; third means for constantly maintaining the pressure at said inlet port at a fixed pressure which is lower than the pressure in said reservoir during brake application; and fourth means for continually conveying liquid from said outlet port to said reservoir during brake application.
Claim 9
Dependent Claim
23 words
A control system according to claim 6, wherein said fourth means comprises a closed line exhausting to the pressure acting on said reservoir.
Claim 10
Dependent Claim
19 words
A control system according to claim 6, wherein said third means vents the center of said toroid to atmosphere.
Claim 11
Dependent Claim
74 words
A control system according to claim 6, further comprising: fifth means for mechanical braking; sixth means for comparing the pressure at a point in a line connecting with the interior of said hydrokinetic brake with the pressure in said reservoir; and seventh means responsive to the attainment of a predetermined ratio of compared pressures as a result of the variation in the pressure at said fixed point for applying said means for mechanical braking.
Claim 12
Dependent Claim
38 words
A control system according to claim 9, wherein said means for mechanical braking are applied by said seventh means to exert an increasing braking torque as said ratio of compared pressures continues to vary beyond said predetermined ratio.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-01-25 | 1980-07-26 | 1981-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-01-25 | 1984-07-26 | 1985-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-01-25 | 1988-07-26 | 1989-01-25 | $7700.00 | Window Closed / Lapsed |