Vehicles for invalids for travel over horizontal and inclined surfaces

Claim 1

A VEHICLE DESIGNED BOTH TO TRAVEL OVER HORIZONTAL SURFACES, AND TO ASCEND OR DESCEND INCLNES, COMPRISING IN COMBINATION (A) A LOAD CONTAINER, (B) A CHASSIS-FRAME, (C) A PAIR OF ENDLESS PRIMARY TRACK ASSEMBLIES INCLINED FROM THE HORIZONTAL ON WHICH SAID VEHICLE MAY BE PROPELLED UPON LONG INCLINES, (D) A SECONDARY TRACK ASSEMBLY WHICH IS SHORT IN LENGTH RELATIVE TO SAID PRIMARY TRACK ASSEMBLIES CONSTITUTING A COMBINED TRACTION-AUGMENTING, CLIMB-STABILIZING, AND SINGLE STEP NEGOTIATING MEANS, POSITIONED IN ADVANCE OF, AND ADJACENT THE FORWARD LOWER END OF SAID PRIMARY TRACK ASSEMBLY, (E) MEANS FOR VARYING THE INCLINATION TO SAID CONTAINER, CHASSIS-FRAME AND PRIMARY TRACK ASSEMBLY AS A UNIT, (F) MEANS INCLUING A PAIR OF WHEELS FOR PROPELLING SAID VEHICLE HORIZONTALLY, AND (G) MEANS FOR DRIVING SAID PRIMARY AND SECONDARY TRACK ASSEMBLIES IN UNISON, SAID TRACK ASSEMBLIES HAVING UPPER RUNS AND UNDER-RUNS, SAID UNDER-RUNS BEING SUBSTANTIALLY TANGENT TO THE LOWER QUADRANTS OF SAID WHEELS, SAID SECONDARY TRACK ASSEMBLY BEING MOVABLE IN A VERTICAL PLANE.