Power-Supplemented Manual Height-Adjusting Wheelchair

A wheelchair with manual power-supplemented height-adjustable seating, comprising:

• a lower frame to which drive wheels attach and opposing forwardly extending arms to which front casters attach for rolling movement across a surface, and including a pair of opposing lower tracks on the sides thereof;
• an upper frame that includes a seat and backrest for a person to occupy the wheelchair, and including a pair of opposing upper tracks on the sides thereof, the upper track on each side aligning with a respective one of the lower tracks;
• a scissor jack assembly having opposing first and second crossed linkage members on one side and opposing first and second crossed linkage members on an opposing side,
• the first linkage member on each side pivotably attached at a first end to a rear portion of the lower track on that side and slidably attached at an opposing second end to the upper track on that side and movable relative thereto from first position in a forward portion of the upper track to a second position remote therefrom,
• the second linkage member on each side pivotably attached at a first end to a rear portion of the upper track on that side and slidably attached at an opposing second end to the lower track on that side and movable relative thereto from first position in a forward portion of the lower track to a second position remote therefrom,
• the first linkage member and the second linkage member on each side pivotally connected at respective medial portions;
• a pair of power cylinders, each attached at a first end to a respective one of the arms extending forwardly on the lower frame and attached at a second end to a portion of a respective one of the upper tracks, extendable between a retracted position and an extended position, and selectively lockable at a selected position;
• the power cylinder when unlocked applies a supplemental vertical force in association with a force applied by the user in the wheelchair for moving the upper frame relative to the lower frame.

A wheelchair with height-adjustable seating, comprising:

• a lower frame to which drive wheels attach and opposing forwardly extending arms to which front casters attach for rolling movement across a surface;
• an upper frame that includes a seat and backrest for a person to occupy the wheelchair;
• a pair of linkage assemblies on opposing sides, each linkage assembly including two opposing spaced-apart parallel elongated members and two opposing end members pivotably connected to opposing ends of the elongated members, the linkage assembly having a forward pivot that connects the linkage assembly to a respective one of the arms and a rear pivot that connects the linkage assembly to the upper frame;
• a pair of power cylinders, each attached to a respective one of the linkage assemblies at a first end to a pivot opposing the forward pivot and at a second end to the rear pivot, extendable between a retracted position and an extended position, and lockable from moving at a selected position;
• the power cylinder when unlocked applies a supplemental vertical force in association with a force applied by a user in the wheelchair to the drive wheels for moving the upper frame relative to the lower frame guided by the linkage assembly pivoting in response to the applied forces.

A method of moving a seat vertically in a wheelchair having a lower frame to which drive wheels attach and opposing forwardly extending arms to which front casters attach for rolling movement across a surface, an upper frame that includes a seat and backrest for a person to occupy the wheelchair, comprising the steps of:

• (a) providing a pair of linkage assemblies on opposing sides, each linkage assembly pivotably attached at a first end to the lower frame and at a second end to the upper frame;
• (b) releasing from selected locked position a pair of power cylinders that extend between a retracted position and an extended position, each power cylinder attached at a first end to a rear portion of the upper frame and at an opposing end to a pivot associated with a forward portion of the lower frame, the power cylinders upon release applying a supplemental force between the upper frame and the lower frame;
• and
• (c) a user seated in the wheelchair applying a force relative to the drive wheels to move the seat vertically relative to the lower frame in the presence of the supplemental force from the power cylinders.