US 5,404,085 A · Multifunction aircraft windscreen wiper control system

Abstract

A wiper control system which includes dual wiper control circuits operating from a single rotary control switch, which is mounted in a cockpit of an aircraft remote from the rest of the wipers and system components which are mounted near an aircraft windscreen in a housing from which a motor converter drive shaft protrudes generally normal to a portion of the airframe surface. The drive shaft is connected to one end of a wiper arm and the second end of the wiper arm is rotatably attached to the wiper blade. The dual wiper control circuits are electrically isolated from each other. The rotary switch includes dual voltage dividers and a single axial rotating member to create an analog voltage output signal representative of the control switch position which is interpreted by a controller circuit. The rotary switch speed selections include a HIGH speed, a LOW speed, an INTERMITTENT delay selection, and also a selection for PARK and OFF. The control circuit provides a digital signal input to a logic circuit which determines the rotary switch position and produces a digital output signal to an amplifier circuit that drives the windscreen wiper motor, which in turn drives the wiper arm at the selected speed. A function decoder and commutation logic device prevents motor overheating and power amplifier overheating.

Claims12

Dependent claims

A multifunction aircraft windscreen wiper control system comprising:

manually operated switch means having a multiple position switch providing at least HIGH, LOW, OFF and PARK positions;
voltage control means responsive to each of said positions for providing an analog input voltage at a different level dependent upon the respective positions;
logic means for providing digital control signals in response to the analog input voltage;
a brushless motor coupled to a shaft for driving an aircraft windshield wiper and responsive to the control signals, said control signals including a run signal for energizing the motor to run and a signal providing a motor brake activation;
means for determining the position of the motor rotor and for providing a motor direction signal as a function of motor position, the means for determining position providing a plurality of groups of output pulses in a pulse train indicative of position;
speed control means for controlling speed of the motor;
and
gating means for selectively gating one of the plurality of groups of pulses in the pulse train, the speed control means controlling the speed of the motor based on ungated pulses in the pulse train.

5 more elements

A windscreen wiper controller for selecting a wiper function comprising:

a wiper function switch, having an input electrical potential and a selectable analog electrical output potential having a level indicative of a desired wiper function the selectable level being variable to indicate the desired one of a plurality of wiper functions;
logic means for receiving the analog electrical output potential and providing a digital output signal indicative of the desired wiper function;
amplifier means for providing a power signal in response to the digital output signal;
wiper driving means for cycling an output shaft in periodic arcuate motion in response to the power signal;
a wiper arm coupled to an end of the output shaft opposite the wiper driving means;
a magnet attached to the output shaft;
and
magnetic field sensing means for detecting the presence of the magnetic field associated with the magnet and providing an input to the logic means indicative of the position of the output shaft.

5 more elements

Dependencies are inferred from the claim text.

Multifunction aircraft windscreen wiper control system

Life of this patent

Multifunction aircraft windscreen wiper control system

Life of this patent

Abstract

Claims12