Patent FR973490A successfully refreshed from Google Patents.
Patent US3880475A successfully refreshed from Google Patents.
US3880475A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Anti-skid system
Assignee: ENHANCED TECHNOLOGY ASSOCIATES Inc A CORP OF NY
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Filing: 1973-12-07
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Granted: 1975-04-29
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Expires: 1993-12-07
Abstract
Abstract An anti-skid control system for a two main wheel aircraft wherein, fundamentally, the system comprises three separate but interrelated circuits. The first such circuit detects incipient skids and causes a corresponding slight reduction in hydraulic brake pressure. A second circuit detects deep skids and correspondingly directs a full dump of brake pressure while directing a modulator to gradually increase the brake pressure back toward the skid level. A third circuit detects a total locked wheel condition and directs a subsequent total release of brake pressure. The anti-skid control system operates in conjunction with the commonly known pilot-metered brake valve type assembly.
Inventors
- 👤 Harold R Booher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:08
CPC Classifications
B; B60; B60T; B60T8/00; B60T8/17; B60T8/1701; B60T8/1703; B64; B64C; B64C25/00; B64C25/32; B64C25/42; B64C25/44; B64C25/46
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
261 words
An anti-skid control system for an aircraft having two main wheels, hydraulic braking means common with each main wheel, electrically controlled valve means regulating hydraulic pressure to the brake means, and wheel speed sensor means associated with each main wheel and generating an electrical signal proportional to wheel rotational velocity, comprising: first circuit means connected to the wheel speed sensor means for producing a first electrical signal when the rate of deceleration of either wheel exceeds a particular level; first and second skid detector circuits, one connected to each of the wheel speed sensor means and each producing a fixed level output signal constituting a second electrical signal; an initializer circuit connected to the skid detector circuits, receiving the output signals therefrom and creating an initialization signal; a modulator circuit connected to and receiving the output signals from the initializer circuit and creating an output signal, said modulator output signal having an amplitude directly related to the frequency of occurrence of said second electrical signal, and said amplitude being immediately increased upon the creation of said initialization signal; second circuit means connected to the wheel speed sensor means for producing a second electrical signal whenever either of the associated wheel velocities drops below a first level while the other wheel velocity remains above a second level; and valve driving circuit means interposed between the two said circuit means, modulator circuit and the electrically controlled valve means, and receiving and responding to the first and second electrical signals and the modulator output signals to regulate the hydraulic pressure of the brake means.
Claim 2
Dependent Claim
261 words
An anti-skid control system for an aircraft having two main wheels, hydraulic braking means common with each main wheel, electrically controlled valve means regulating hydraulic pressure to the brake means, and wheel speed sensor means associated with each main wheel and generating an electrical signal proportional to wheel rotational velocity, comprising: first circuit means connected to the wheel speed sensor means for producing a first electrical signal when the rate of deceleration of either wheel exceeds a particular level; first and second skid detector circuits, one connected to each of the wheel speed sensor means and each producing a fixed level output signal constituting a second electrical signal; an initializer circuit connected to the skid detector circuits, receiving the output signals therefrom and creating an initialization signal; a modulator circuit connected to and receiving the output signals from the initializer circuit and creating an output signal, said modulator output signal having an amplitude directly related to the frequency of occurrence of said second electrical signal, and said amplitude being immediately increased upon the creation of said initialization signal; second circuit means connected to the wheel speed sensor means for producing a second electrical signal whenever either of the associated wheel velocities drops below a first level while the other wheel velocity remains above a second level; and valve driving circuit means interposed between the two said circuit means, modulator circuit and the electrically controlled valve means, and receiving and responding to the first and second electrical signals and the modulator output signals to regulate the hydraulic pressure of the brake means.
Claim 3
Dependent Claim
102 words
The anti-skid control system as recited in claim 1 wherein the first circuit means comprises: first and second deceleration circuits, one connected to each of the wheel speed sensor means, and producing outputs indicative of the rate of deceleration of the respective wheels, a variable deceleration reference signal source connected to the first and second skid detector circuits and producing a varying output signal level controllable by the first and second skid detector circuits; and a comparator circuit interconnected between the first and second deceleration circuits and the reference signal source and producing a fixed level output constituting said first electrical signal.
Claim 4
Dependent Claim
63 words
The anti-skid control system as recited in claim 1 wherein the valve driving circuit comprises a summing circuit interconnecting the first and second circuit means and The modulator and a valve current driver connected to and receiving an output voltage signal from the summing circuit and applying a current output signal proportional to said output voltage signal to the electrically controlled valve means.
Claim 5
Dependent Claim
210 words
An anti-skid control system for an aircraft having two main wheels, hydraulic braking means common with each main wheel, electrically controlled valve means regulating hydraulic pressure to the brake means, and wheel speed sensor means associated with each main wheel and generating an electrical signal proportional to wheel rotational velocity, comprising: first circuit means connected to the wheel speed sensor means for producing a first electrical signal when the rate of deceleration of either wheel exceeds a particular level; second circuit means connected to each of the wheel speed sensor means for producing a second electrical signal whenever either of the associated wheel velocities drops more than a certain amount below the ground speed of the aircraft; a locked wheel detector connected to the first circuit means producing an output signal when either of the associated wheel velocities drops below a first level; a locked wheel arming circuit connected to the first circuit means for producing an output signal when either of the associated wheel velocities exceeds a second level; and an anti-lock logic circuit connected to the locked wheel detector and locked wheel arming circuit and supplying a fixed amplitude output signal to the valve driver circuit when outputs from said locked wheel detector and arming circuits are co-existent.
Claim 6
Dependent Claim
210 words
An anti-skid control system for an aircraft having two main wheels, hydraulic braking means common with each main wheel, electrically controlled valve means regulating hydraulic pressure to the brake means, and wheel speed sensor means associated with each main wheel and generating an electrical signal proportional to wheel rotational velocity, comprising: first circuit means connected to the wheel speed sensor means for producing a first electrical signal when the rate of deceleration of either wheel exceeds a particular level; second circuit means connected to each of the wheel speed sensor means for producing a second electrical signal whenever either of the associated wheel velocities drops more than a certain amount below the ground speed of the aircraft; a locked wheel detector connected to the first circuit means producing an output signal when either of the associated wheel velocities drops below a first level; a locked wheel arming circuit connected to the first circuit means for producing an output signal when either of the associated wheel velocities exceeds a second level; and an anti-lock logic circuit connected to the locked wheel detector and locked wheel arming circuit and supplying a fixed amplitude output signal to the valve driver circuit when outputs from said locked wheel detector and arming circuits are co-existent.
Claim 7
Dependent Claim
64 words
The anti-skid control system as recited in claim 4 which further includes a spin-up detector circuit connected to the first circuit means and supplying a signal to the anti-lock logic circuit to maintain a full release of brake pressure from the time the aircraft touches down upon the runway and extended while either of the wheels associated with the first circuit means is accelerating.
Claim 8
Dependent Claim
42 words
The anti-skid control system as recited in claim 5 which further includes a bounce detector circuit connected to the first circuit means and presenting a signal to the anti-lock logic until both of the wheels have accelerated to a preselected velocity level.
Claim 9
Dependent Claim
44 words
The anti-skid control system as recited in claim 6 which further includes a ground sensing switch interconnected between the wheels and the anti-lock logic and presenting a signal to said logic when the aircraft is airborne to guarantee full hydraulic pressure release upon landing.
Claim 10
Dependent Claim
56 words
The anti-skid control system as recited in claim 6 wherein the anti-lock logic circuit is connected directly to the valve means and is operative to apply a signal to the valve means to disable the anti-skid circuitry at ground velocities below a particular level so as to allow taxiing maneuvers to be performed without anti-skid interference.
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) | 1978-04-28 | 1978-10-28 | 1979-04-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-28 | 1982-10-28 | 1983-04-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-28 | 1986-10-28 | 1987-04-29 | $7700.00 | Window Closed / Lapsed |