Mid-wheel drive power wheelchair

A power wheelchair comprising:

• a support frame;
• a seat mounted to the support frame, the seat having a seat portion for supporting a person's thighs and buttocks and a back portion for supporting a person's back when seated upright in the seat;
• a pair of normally ground engaging drive wheels on the support frame rotatable about transverse axes, the drive wheels positioned below the seat portion and forward of the back portion;
• motor means for rotatably driving each of the drive wheels to provide powered movement of the wheelchair, the motor supported on the frame;
• controller means for controlling the driving of the drive wheels by their respective motors;
• at least one battery for supplying power to the at least one motor, the battery supported on the frame;
• at least one normally ground-engaging castor wheel connected to the frame behind the drive wheels and rearward of the back of the seat;
• a pair of anti-tip idler wheels positioned forward of the drive wheels and the seat, the pair of anti-tip wheels comprising all of the wheels forward of the drive wheels and the respective anti-tip wheels positioned on opposite sides of the frame and positioned off the ground when the drive wheels and the castor wheel are in their normal ground-engaging position on level ground;
• and
• a resilient mounting for each said anti-tip idler wheels, each said mounting comprising a support arm attached at a rear end to the frame and the anti-tip idler wheel rotatably supported at a front end of the support arm, the idler wheel being movable upwardly against the resilience of mounting, the upward movement being forward of the attachment of the support arm to the frame.

A power wheelchair comprising:

• a support frame;
• a seat removably mounted to the support frame, the seat having a seat portion for supporting a person's thighs and buttocks and a back portion for supporting a person's back when seated upright in the seat;
• a pair of normally ground engaging drive wheels on the support frame rotatable about transverse axes, the drive wheels positioned below the seat portion and forward of the back portion;
• motor means for rotatably driving each of the drive wheels to provide powered movement of the wheelchair, the respective motor means supported on opposite sides of the frame;
• controller means for controlling the driving of the drive wheels by their respective motors;
• at least one battery for supplying power to the at least one motor, the battery supported on the frame;
• at least one normally ground-engaging castor wheel connected to the frame behind the drive wheels and rearward of the back of the seat;
• a pair of anti-tip idler wheels, each said anti-tip wheel positioned forward of the drive wheels and the seat, on opposite sides of the frame and off the ground when the drive wheels and the castor wheel are in their normal ground-engaging position on level ground, the anti-tip wheels comprising all of the wheels positioned forward of the drive wheels;
• a resilient mounting for each said anti-tip wheels, each said mounting attached at a rear end to the frame and the anti-tip wheel rotatably supported at a front end, the anti-tip wheel being movable upwardly in a substantially arcuate motion relative to and forward of the attachment of the mounting to the frame, the upward movement being resisted by the resilient mounting in the event of the wheel chair pitching forward and in the event of either of the anti-tip wheels contacting an obstacle;
• and
• an adjustable foot rest for supporting the feet of an occupant when positioned in the seat footrest supported on the frame forward of the seat and between the anti-tip wheels.