Folding wheelchair

A wheelchair comprising:

• left and right side frames, each side frame having a lower side frame member and an upper side frame member;
• and
• a folding mechanism for connecting the left and right side frames to each other in a folding and unfolding relationship, the folding mechanism including:
• cross struts rotatably connected to the lower side frame members, the cross struts including one or more cross struts from the left side frame pivotally connected to one or more cross struts from the right side frame;
• hinge links connected to the upper side frame members, the hinge links having a first end pivotally connected to the upper side frame member and a distal end, with the hinge links being pivotally connected at their intermediate portions to the cross struts, wherein relative rotation of the cross struts with respect to each other causes pivoting of the hinge links relative to the upper side frame members, and causes the left and right side frames to move closer together in a folding movement or farther apart in an unfolding movement;
• and
• a lock for locking the hinge links together when the folding mechanism is unfolded to form a truss between the left and right upper side frame members, thereby fixing the distance between the left and right upper side members, the lock having a pivotally mounted handle, the handle being mounted so that pivoting the handle to a locked position places the handle in a toggle over center condition.

A wheelchair comprising:

• left and right side frames, each side frame having a lower side frame member and an upper side frame member;
• and
• a folding mechanism for connecting the left and right side frames to each other in a folding and unfolding relationship, the folding mechanism including:
• cross struts rotatably connected to the lower side frame members, the cross struts including one or more cross struts from the left side frame pivotally connected to one or more cross struts from the right side frame;
• hinge links connected to the upper side frame members, the hinge links having a first end pivotally connected to the upper side frame member and a distal end, with the hinge links being pivotally connected at their intermediate portions to a cross strut, wherein relative rotation of the cross struts with respect to each other causes pivoting of the hinge links relative to the upper side frame members, and causes the left and right side frames to move closer together in a folding movement or farther apart in an unfolding movement;
• and
• a lock for locking the hinge links together when the folding mechanism is unfolded to form a rigid truss between the left and right upper side frame members, thereby fixing the distance between the left and right upper side members, the lock having a pivotally mounted handle, the handle being mounted so that lifting the handle in an upward direction both unlocks the left and right hinge links from each other, and pivots the hinge links relative to the side frames to fold the folding mechanism, with the folding capable of being accomplished with one hand by grasping and lifting the handle.