Foldable midwheel drive power chair

A power chair comprising:

• a. a frame transversely foldable between operating and transport positions;
• b. a seat connected to said frame;
• c. a pair of drive wheels connected to said frame and rotatable about transverse axes below a portion of said seat supporting an occupant's thighs;
• d. motors for driving respective drive wheels, respective motor/drive wheel combinations being pivotally connected to said frame;
• e. at least one ground-engaging idler wheel connected to said frame and located rearward of said drive wheels;
• f. at least one anti-tip wheel forward of said drive wheels and positioned above ground;
• g. a spring-strut assembly for resiliently resisting upward movement of said anti-tip wheel upon encountering an obstacle, said spring-strut comprising
• i. a strut connected to said anti-tip wheel and movable upwardly therewith;
• ii. a spring coiled about said strut;
• iii. means connected to said frame for constraining an upper end of said spring against upward movement while permitting slidable upward passage of said strut there through including a shaft portion slidably receiving said strut and fitting within the interior of said spring and a cap portion connecting with an upper portion of said shaft portion, having a exterior upper surface facilitating relative rotary motion of said constraining means respecting said frame responsively to an associated anti-tip wheel encountering an obstacle, upwardly displacing said strut and compressing said spring.

A power chair comprising:

• a. a frame transversely foldable between operating and transport positions;
• b. a seat connected to said frame;
• c. a pair of drive wheels connected to said frame and rotatable about transverse axes below a portion of said seat supporting an occupant's thighs;
• d. motors for driving respective drive wheels, respective motor/drive wheel combinations being pivotally connected to said frame;
• e. at least one ground-engaging idler wheel connected to said frame and located rearward of said drive wheels;
• f. at least one anti-tip wheel forward of said drive wheels and positioned above ground;
• g. a pair of transversely spaced arms positioned on respective sides of said power chair;
• and
• h. means connected to said frame for adjustably positioning said arms at a plurality of heights, the means comprising
• i a tongue member fixedly connected to said arm, having a plurality of recesses in the surface thereof;
• ii. a housing member connected to said frame and having a receptacle of varying depth formed therein, being movable among positions at which various parts of said receptacle having different depths communicate with a selected one of said recesses;
• and
• iii. movable means resident in said receptacle and being of a size for receipt of a portion thereof by a recess with which said receptacle is communicating for interfering with movement of said tongue relative to said housing when said movable means is in a relatively shallow portion of said receptacle and freely permitting movement of said tongue when said movable means is in a relatively deep portion of said receptacle.

A power chair comprising:

• a. a frame transversely foldable between operating and transport positions;
• b. a seat connected to said frame;
• c. a pair of drive wheels connected to said frame and rotatable about transverse axes below a portion of said seat supporting an occupant's thighs;
• d. motors for driving respective drive wheels, respective motor/drive wheel combinations being pivotally connected to said frame;
• e. at least one ground-engaging idler wheel connected to said frame and located rearward of said drive wheels;
• f. at least one anti-tip wheel forward of said drive wheels and positioned above ground, connected to said frame for movement relative to said frame upon encountering an obstacle;
• and
• g. spring-strut assemblies for resiliently resisting upward movement of said anti-tip wheel upon encountering an obstacle, comprising:
• i. a strut connected to said anti-tip wheel and moveable upwardly therewith;
• ii. a spring coiled about said strut;
• iii. means connected to said frame for constraining an upper end of said spring against upward movement while permitting slidable upward passage of said strut therethrough including a shaft portion slidably receiving said strut and fitting within the interior of said spring and a cap portion connecting with an upper portion of said shaft portion, having a curved exterior upper surface facilitating relative rotary motion of said constraining means respecting said frame responsively to an associated anti-tip wheel encountering an obstacle, upwardly displacing said strut and compressing said spring;
• wherein said frame has a pair of rigid parallel side members connected by a plurality of cross members each comprising a plurality of pivotally connected links;
• wherein said cross members are transverse to said side members and said pivotal connections rotate about longitudinal axes.

A power wheel chair comprising:

• a. a frame transversely foldable between operating and transport positions;
• b. a seat connected to said frame;
• c. a pair of drive wheels connected to said frame and rotatable about transverse axes;
• d. at least one ground-engaging idler wheel connected to said frame;
• e. a pair of transversely spaced arms positioned on respective sides of said power wheel chair;
• and
• f. means connected to said frame for adjustably positioning said arms at a plurality of heights, the means connected to said frame comprising
• i. a tongue member fixedly connected to said arm, having a plurality of recesses in the surface thereof;
• ii. a housing member connected to said frame and having a receptacle of varying depth formed therein, being movable among positions at which various parts of said receptacle having different depths communicate with a selected one of said recesses;
• and
• iii. movable means resident in said receptacle and being of a size for receipt of a portion thereof by a recess with which said receptacle is communicating for interfering with movement of said tongue relative to said housing when said movable means is in a relatively shallow portion of said receptacle and freely permitting movement of said tongue when said movable means is in a relatively deep portion of said receptacle.