Patent ID: 7553205
Filing Date: 2009-06-30
Classification: B63C,Y10T

Abstract:
1. An electromechanical actuator comprising: a housing having a lengthwise axis and a bore with a first end and a second end spaced apart along the axis; a plunger, movable along the axis, for imparting linear force to an object external to the housing; a first sleeve, fixedly engaged with the housing, extending lengthwise toward the second end of the housing, the outside diameter of the sleeve radially spaced apart inwardly from the bore of the housing, having a plurality of circumferentially spaced apart holes for receiving balls; a second sleeve, mounted on the exterior of the first sleeve and slidable therealong, having a first end and second end corresponding with the ends of the housing, having structure at the second end for moving the plunger lengthwise along said axis toward said second end of the housing while sliding on the first sleeve, and having an interior circumferential groove for engaging portions of one or more balls positioned in the holes of the first sleeve; a plurality of balls positioned within said plurality of holes of said first sleeve; a main spring positioned within the interior of said second sleeve, for creating separation force between the first and second sleeves, and for thereby urging the second sleeve to move toward said second end of the housing; a shuttle, slidable within the interior of the second sleeve, shaped as a stepped cylinder, having a first end and second end, the ends corresponding with said housing ends, the first end having a larger diameter than the second end; the shuttle having a tapered transition section between the first and second diameter portions; wherein, when said shuttle first end slides to proximity of said circumferential holes of the first sleeve, said balls within said holes are thrust outwardly, to thereby engage said circumferential groove of the second sleeve; the shuttle further having a bore cavity at the first end, for receiving a shuttle spring; a shuttle spring, positioned within said bore cavity of the shuttle, for urging the shuttle lengthwise so that the shuttle second end contacts and urges outwardly said balls; and, an electromagnetic coil for imparting lengthwise motion to the shuttle in a direction opposite the direction of urging of said shuttle spring; wherein, when the balls are engaged with said second sleeve interior groove, the second sleeve is fixed relative to the first sleeve and relative to the housing; and, wherein, when the shuttle second smaller end is in proximity to said circumferential holes of the second sleeve, the balls may move inwardly to disengage from said second sleeve interior circumferential groove, thus enabling said main spring to move the second sleeve and thereby said plunger.