The Freedom Wheelchair

   Wheelchairs conform to a standard design that is familiar to all.  It is
collapsible so that it can fit into any car.  But what it can't do is allow
the user to back up over a common home toilet when necessary and use it from
the wheelchair.  This is a prototype wheelchair for double amputees above the
knee to allow that option.
This was a used Everest & Jennings Vista.
   It is 24 & 1/2" wide, has 24" wheels and 8" casters.  The clearance over a
toilet seat can be from set comfortably from 16" to 18 & 1/2".  (Any greater
height will require riser boards under the wheels.) The clear width underneath
is 14 & 3/4" (our toilet is 14 & 1/4" wide). The distance from the wall to the
center of our toilet bowl is 18" to 20".
The first modifications to the Vista.
   There are four corner plates to give rigidity after the central X-hinge,
which allows the chair to collapse, is cut away.  Where footrests had been
there is now a steel cross brace for side-to-side rigidity.  There is also a
steel cross brace between the back posts.  (So Freedom cannot collapse, now.)
More modifications.
   The X-hinge has been removed.  The cross brace has been welded to the
footrest mounts.  The footrest mounts are welded to the mounting pins.
The prototype over our standard toilet.
   The sliding-seat height from the floor will depend on the toilet seat
height.  Once it is set, no higher toilet can be used, but the height is
selectable.  But height should be close to what is normally needed or else it
could be a long way down for the user to have to lower and raise themselves.
A ball-bearing drawer-slide seat mount.
   The heavy-duty drawer slides are bolted to the corner braces.
The plywood seat base all the way back.
The seat all the way out.
   Seat travel is 16 inches.
The thigh strap.
   Hooks are hose-clamped to the armrests on the prototype. The strap goes
under both thighs.
The seat-moving linkages.
   The linkages are connected to a 1/4" shaft. The shaft turns 73 degrees
to move the seat from full back to full out.  The spring on the shaft crank
arm toggles to move the seat out or in as soon as the user lifts up. (The rail
and seat rollers shown did not work well and were changed.)
 The toggling mechanism with the seat back.
 The toggling mechanism with the seat out.
The seat moving out.
   This only happens when the user lifts up off of the seat. For this video a
weight is lifted off the seat.
   The user raises the toilet seat and then backs the wheelchair over the
toilet.  Clothing is worked down as usual.   The thigh strap is put under the
thighs.  The toggle arm is moved down.
   Now the wheels, the handrims and the stainless panels on the wheelchair are
gripped.  When the user lifts up, the seat will move out.  The user can then
lower themselves to the seat.  They might also want to release the thigh strap
for more comfort.  When ready, move the toggle arm up and reverse these steps.