Wheelchair stair climbing control system

A personal transport vehicle comprising:

• a track means for moving said vehicle over an inclined surface;
• a member coupled to said vehicle proximate an end of said vehicle, for cushioning a tilting movement of said vehicle;
• a tube coupled to one of said vehicle and said member;
• a piston extending into said tube and coupled to a one of said vehicle and said member not coupled to said tube;
• means for restricting the flow of a first fluid out of a first side of said tube to limit the speed at which the combination of said tube and said piston compresses;
• means for forcing a second fluid into a second side of said tube to force a compression of said piston and tube combination;
• and
• means for providing an increased flow of said first fluid out of said first side of said tube coincident with operation of said means for forcing to allow a quick compression of said tube and piston combination.

A personal transport vehicle comprising:

• track means for moving said vehicle over an inclined surface;
• a member coupled to said vehicle proximate an end of said vehicle, for cushioning a tilting movement of said vehicle;
• a tube coupled to one of said vehicle and said member;
• a piston extending into said tube and coupled to a one of said vehicle and said member not coupled to said tube;
• means for restricting the flow of a first fluid out of a first side of said tube to limit the speed at which the combination of said tube and said piston compresses, including a fluid reservoir coupled to said first side of said tube and a valve for restricting a flow between said first side of said tube and said reservoir;
• means for forcing air into a second side of said tube to force a compression of said piston and tube combination;
• a bypass valve for bypassing said restricted flow valve to provide an increased flow of said first fluid out of said first side of said tube coincident with operation of said means for forcing to allow a quick compression of said tube and piston combination;
• and
• a sensor for detecting an up position of said member.

A personal transport vehicle comprising:

• track means for moving said vehicle over an inclined surface;
• a member coupled to said vehicle proximate an end of said vehicle, for cushioning a tilting movement of said vehicle;
• a tube coupled to one of said vehicle and said member;
• a piston extending into said tube and coupled to a one of said vehicle and said member not coupled to said tube;
• means for restricting the flow of a first fluid out of a first side of said tube to limit the speed at which the combination of said tube and said piston compresses;
• means for forcing a second fluid into a second side of said tube to force a compression of said piston and tube combination;
• means for providing an increased flow of said first fluid out of said first side of said tube coincident with operation of said means for forcing to allow a quick compression of said tube and piston combination;
• a sensor for detecting the angle of incline of a surface being traversed by said vehicle;
• means for adjusting a tilt of said seat in accordance with said incline;
• and
• means responsive to said sensor, for preventing movement of said vehicle over an incline of predetermined steepness until said means for adjusting has tilted said seat to a predetermined minimum angle.