Abstract In large aircraft brakes, antiskid features are mandatory. Heretofore, it has been known to include a modulator system in the antiskid circuit to establish tire-runway coefficient frictions so that maximum braking pressure could be applied throughout the stop without causing a skid condition to occur. The invention incorporates a modification into a modulator circuit causing the modulator circuit to discharge more rapidly after the first antiskid cycle than it discharges throughout the remainder of the landing run so as to overcome misinformation to the circuit which occurs upon initial touchdown when the full weight of the airplane is not on the wheel. The circuit to accomplish this result incorporates a capacitor which is adapted to charge upon the first discharge of the loading capacitor in the modulator circuit, thereby in effect cancelling out the effect of the modulator circuit on the first skid.
In an antiskid braking system the combination of a rotatable wheel means to supply hydraulic braking pressure to the wheel, valve means to adjustably restrict the hydraulic pressure actually applied to the wheel, means to represent the wheel rotation as an electrical signal, skid detector means to control the braking pressure to the wheel by supplying a control signal to the valve means, and a modulation circuit acting in accordance with the control signal to adjust the valve means to a hydraulic pressure slightly lower than that which caused a skid upon returned braking operation after actuation of the valve means which is characterized by circuit means associated with the modulation circuit to allow the modulation circuit to respond more rapidly to the control signal during at least the first detection of a skid by the skid detector means so that true wheel loading conditions can be established before the modulation circuit begins to function at a normal predetermined rate.
Claim 2
Dependent Claim
160 words
In an antiskid braking system the combination of a rotatable wheel means to supply hydraulic braking pressure to the wheel, valve means to adjustably restrict the hydraulic pressure actually applied to the wheel, means to represent the wheel rotation as an electrical signal, skid detector means to control the braking pressure to the wheel by supplying a control signal to the valve means, and a modulation circuit acting in accordance with the control signal to adjust the valve means to a hydraulic pressure slightly lower than that which caused a skid upon returned braking operation after actuation of the valve means which is characterized by circuit means associated with the modulation circuit to allow the modulation circuit to respond more rapidly to the control signal during at least the first detection of a skid by the skid detector means so that true wheel loading conditions can be established before the modulation circuit begins to function at a normal predetermined rate.
Claim 3
Dependent Claim
64 words
A braking system according to claim 1 where the modulation circuit includes a first capacitor which is charged upon normal rotation of the wheel, and the circuit means associated with the modulation circuit includes a second capacitor arranged to be charged rapidly by the first discharge of the first capacitor, and to bleed off slowly thereafter to delay further discharges by said first capacitor.
Claim 4
Dependent Claim
37 words
A system according to claim 2 where the second capacitor is connected to the output side of the first capacitor through a one-way diode, and a large resistor connects the output of the second capacitor to ground.
Claim 5
Dependent Claim
25 words
A system according to claim 1 where the modulation circuit includes a variable resistor to provide a controlled discharge of the first capacitor to ground.