Stair-climbing wheelchair

A stair-climbing wheelchair having a seat, a frame supporting the seat, and a set of wheels on which the wheelchair can be propelled, the improvement comprising:

• a spaced-apart pair of elongate track assemblies mounted to said frame extending underneath said seat between said set of wheels in a front to back direction relative to the wheelchair, in an inoperative storage condition said track assemblies being spaced above a surface on which the wheelchair is supported by said set of wheels and in an operative drive condition said track assemblies engaging a surface on which the wheelchair is supported for purposes of transporting the wheelchair along a path of travel to thereby enable the wheelchair to descend and ascend an obstacle such as steps, curbs or the like;
• each of said track assemblies including an elongate guide member carrying an endless belt, said guide member having front and rear end sections each supporting a roller over which said endless belt is mounted for rotation about said rollers, said guide member being upwardly arched between said end sections thereby permitting said endless belt to deflect upwardly between said rollers when said endless belt engages an obstacle such as a step, curb or the like;
• said endless belt on each of said guide members extending in a taut condition on said rollers, at least one of said rollers being movably mounted on said guide member to provide said endless belt with an amount of slack to enable said endless belt to deflect upwardly between said rollers, said at least one roller being resiliently biased by a spring mechanism to maintain said endless belt in a taut condition at all times including when said belt is deflected upwardly between said rollers;
• and
• each of said track assemblies including an upwardly inclined tail section extending from said rear end section of said arched elongate guide member, each tail section including a pair of rollers about which an endless belt revolves and each tail section being offset inwardly of said arched elongate guide member.

A track assembly for a motorized device adapted to traverse obstacles, the improvement comprising:

• a spaced-apart pair of elongate track assemblies mounted to a frame for purposes of transporting the frame along a path of travel to thereby enable the device to traverse obstacles;
• each of said track assemblies including an elongate guide member carrying an endless belt, said guide member having front and rear end sections each supporting a roller over which said endless belt is mounted for rotation about said rollers, said guide member being upwardly arched between said end sections thereby permitting said endless belt to deflect upwardly between said rollers when said endless belt engages an obstacle;
• said endless belt on each of said guide members extending in a taut condition on said rollers, at least one of said rollers being movably mounted on said guide member to provide said endless belt with an amount of slack to enable said endless belt to deflect upwardly between said rollers, said at least one roller being resiliently biased by a spring mechanism to maintain said endless belt in a taut condition at all times including when said belt is deflected upwardly between said rollers;
• and
• each of said track assemblies including an upwardly inclined tail section extending from said rear end section of said arched elongate guide member, each tail section including a pair of rollers about which an endless belt revolves and each tail section being offset inwardly of said arched elongate guide member.