Stairclimbing wheelchair

Claim 1

A WHEELCHAIR COMPRISING A SEAT FRAME HAVING SIDES, SAID SIDES HAVING GROUND-ENGAGING WHEELS, TRACTION ASSEMBLIES SLIDABLY ENGAGED WITH THE FRAME SIDES AND ADAPTED TO BE MOVED DOWNWARDLY FROM ELEVATED POSITIONS WHEREBY THE TRACTION ASSEMBLIES ARE OUT OF CONTACT WITH THE GROUND AND THE FRAME IS SUPPORTED ON ITS WHEELS TO A DEPRESSED POSITION WHEREIN THE FRAME WHEELS ARE OUT OF CONTACT WITH THE GROUND AND THE TRACTION ASSEMBLIES SUPPORT THE FRAME ON THE GROUND, OPERATING MEANS ON THE FRAME AND CONNECTED WITH THE TRACTION ASSEMBLIES, EACH OF SAID TRACTION ASSEMBLIES COMPRISING A HORIZONTAL HOUSING, INBOARD AND OUTBOARD TRACTION SHOES SUPPORTED WITHIN THE HOUSING AND ADAPTED TO PROJECT AT DIFFERENT TIMES FROM THE HOUSING INTO CONTACT WITH THE GROUND, AND DRIVING MEANS MOUNTED ON THE FRAME AND CONNECTED TO THE SHOES FOR PRODUCING ALTERNATE ELEVATION AND DEPRESSION OF THE SHOES ACCOMPANIED BY MOVEMENTS OF THE SHOES IN OPPOSITE DIRECTIONS, AND DRIVING MEANS ON A FRAME SIDE AND OPERATIVELY CONNECTED TO THE SHOES, SAID TRACTION SHOES BEING SLIDABLY ENGAGED WITH THEIR HOUSING FOR ENDWISE MOVEMENTS RELATIVE THERETO, SAID TRACTION SHOES COMPRISING RESILIENT BARS HAVING UPTURNED END PORTIONS BEARING AGAINST THE HOUSING, AND RESILIENT AND COMPRESSIBLE NOTCHED TREADS FIXED TO THE UNDERSIDE OF THE BARS, SAID DRIVING MEANS COMPRISING LONGITUDINALLY SPACED PAIRS OF INBOARD AND OUTBOARD ROTORS MOUNTED ON THE HOUSING, SAID ROTORS COMPRISING SEMI-CIRCULAR CAM WHEELS, THE CAM WHEELS OF EACH ROTOR BEING DIAMETRICALLY OPPOSED TO EACH OTHER AND ENGAGEABLE AT DIFFERENT TIMES WITH THE SHOE BARS FOR DEPRESSING THE SAME, SOME OF SAID CAM WHEELS BEING SECTOR GEARS, SAID SHOE BARS AND SAID HOUSING HAVING RACKS WITH WHICH THE ROTOR GEARS ARE OPERATIVELY ENGAGEABLE AT DIFFERENT TIMES FOR IMPARTING ENDWISE MOVEMENTS OF THE TRACTION SHOES IN OPPOSITE DIRECTIONS, AND MANUALLY OPERATED GEAR MEANS CONNECTED TO THE SECTOR GEARS.