Wheelchair control circuit
AssigneePossum Controls Limited
InventorsMichael Lloyd Jones, Peter Meredith Jobson
Life of this patent
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Abstract
A wheel chair motor control circuit for a wheel chair having two independently controllable motor-driven wheels. The user has a "joystick" control operable from a datum position to move the wipers of two potentiometers both independently and simultaneously from their corresponding datum positions. A first, proportional control circuit is provided for each motor to supply it with drive power proportional to the magnitude of the deviation of its corresponding potentiometer wiper from datum and a second reversing circuit is provided for each motor to operate a reversing relay connected thereto in accordance to the direction of the deviation of its corresponding potentiometer wiper.
Claims13
A control circuit suitable for use in controlling the two electric motors of a wheelchair of the type specified, comprises two control potentiometers with respective wipers which are connected to a common control lever, said control lever having a datum position and being operable from the datum position to manipulate the positions of the wipers of the potentiometers both independently and simultaneously from their corresponding datum positions, terminals through which voltages can be applied across the resistance-elements of the potentiometers whereby the output voltages at the wipers have magnitudes dependent upon the positioning of the control lever, a predetermined magnitude corresponding to the datum position and deviations on opposite sides of the predetermined magnitude constituting control signals for forward and reverse operation respectively of the two motors, each motor having a reversing relay connected thereto and the energising circuit of each reversing relay including a detector circuit individual to the relay and the corresponding control potentiometer, the detector circuit including means for detecting output voltage from its associated control potentiometer representative of a control signal for reverse operation of the motor to energise the associated reversing relay, and further means for driving each motor in dependence upon the deviation in the magnitude of the output voltage at the wiper of its associated control potentiometer from the datum.
Dependencies are inferred from the claim text.