Patent ID: 8234944
Filing Date: 2012-08-07
Classification: A61G,B66C,F16H,H02K,Y10T

Abstract:
1. An actuator which comprises: a rotatable spindle which has a forward end and a rear end, a spindle nut mounted on said spindle to move along said spindle between said forward and rear ends thereof upon rotation of said spindle, a reversible electric motor, a transmission interconnected between said motor and said rear end of said spindle to rotate said spindle, an activation rod attached to said spindle nut to extend towards and beyond said forward end of said spindle, a front mount for attachment to a movable part of an item of an apparatus, and an emergency retraction mechanism connected between the front mount and the activation rod, said emergency retraction mechanism comprising: a first cylindrical part attached to the front mount, a second cylindrical part attached to the activation rod, a bearing located between said first and second cylindrical parts to enable rotative rotation therebetween, an operating handle around said first cylindrical part, and a coil spring around and in contact with outer peripheries of said first and second cylindrical parts, said coil spring having a larger number of windings wrapped around and in contact with the outer periphery said second cylindrical part than the number of windings wrapped around and in contact with the outer periphery of said first cylindrical part, said coil spring having a first end attached to said operating handle and a second end connected to said second cylindrical part, rotation of said operating handle operating to expand the coil spring out of contact with said first cylindrical part and enable relative motion between the first and second cylindrical parts, and enable retraction of said spindle nut towards said rear end of said spindle.