Protection circuitry 10 for control electronics of an electric wheelchair comprises a current pathway, a measurement circuit 12 measuring a current I in the pathway, a switch 16 connected in series with the pathway, and control circuitry 14 which switches the switch from a first state to a second state if the measured current exceeds a threshold for more than a predetermined trip time. The trip time is less than 100 microseconds and the threshold current is greater than 8 amps. The control electronics is a modular system 20 comprising a plurality of modules 24 each being selectively connectable to the others via cables 28. Each cable comprises a plurality of electrically isolated conductive pathways between a first connector and a second connector. One of the isolated pathways provides the current pathway. In the second state, the switch may suppress current flow in the pathway in a first direction but permit current flow in a second direction via a diode (64, figure 4B) to allow battery charging. The protection circuitry allows high currents to be delivered to wheelchair components while quickly suppressing short circuits caused by cables being pinched or crushed by the articulated joints 26 of rehabilitation wheelchairs. The formation of carbon tracks is thereby prevented.
Protection apparatus and method for an electric wheelchair
2021-06-16
Patent
Elektronische Ressource
Englisch
IPC: | B60L PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES , Antrieb von elektrisch angetriebenen Fahrzeugen / A61G TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS , Transport, persönliche Beförderungsmittel, oder Lagerung besonders ausgebildet für Kranke oder Behinderte / H01H Elektrische Schalter , ELECTRIC SWITCHES / H02H EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS , Schutzschaltungsanordnungen |
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