Patent ID: 7504921

Claim:
An actuator for moving a load, comprising: a frame forming a race between two surfaces of the frame; at least two elements joined together by at least one flexible member, the elements and the at least one flexible member being disposed between the two surfaces of the frame that forms said race, one of the elements further being attached to the load by a portion of the at least one flexible member; a moving mechanism disposed to selectively move said at least two elements and selectively retain and release said at least two elements in corresponding positions relative to said two surfaces of the race so as to move a first one of said at least two elements from said first surface of said race to said second surface of said race while retaining a second one of said at least two elements in a fixed position against one of said first and second surface of said race and; whereby the actuator incrementally effects movement of the load, by successively changing said corresponding positions of the at least two elements relative to said two surfaces of the race wherein said at least two elements are displaced along a length of said race thereby causing displacement of said load when said at least two elements by independently and successively moving and retaining said element to opposite surface of said race.