Spring assist system for gravity deployment of stowed platform wheelchair lifter

摘要

A wheelchair platform free fall control system comprising use of a tension means, such as at least one spring, biasing together the long and short arms of a lever arm assembly that keeps the lever arm slide block in contact with a lifting arm during gravity-down deployment of said platform from an over-vertical stowed position to a horizontal transfer position. A compression means may be used in conjunction with the lifting arm assembly to assist in overcoming the resting momentum of the lift platform mass from over-vertical outwardly until gravity takes over. The tension means may be one or more springs and the compression means may be a gas spring. The forces are preselected to provide lifting assembly over-vertical assist while keeping the sliding block in substantial contact with an arm of the lifting assembly. The springs can be used with a stud/slot interlock. Torsion springs are preferably eliminated.