Patent ID: 6568293
Filing Date: 2003-05-27
Classification: F16H,Y10T

Abstract:
An apparatus for producing linear motion comprising:an elongate rod of circular cross-section arranged to be continuously rotated in a first direction about an elongate axis; and a carriage arranged to mounted on the rod so as to permit axial movement of the carriage along the length of the rod; wherein the carriage comprises: at least one first roller member arranged to contact the rod such that an axis of rotation of said roller member is at a first angle to the axis of rotation of the rod; said apparatus being characterized by further comprising: at least one first piezo-electric actuator means arranged to carry the first roller member for pressing the first roller member against the rod to cause rotation of the roller member, said piezo-electric actuator means comprising a first substantially flat resilient leg member and a second substantially flat resilient leg member, said first and said second leg members being connected by a substantially stiff bight portion, said leg members being arranged to lie substantially parallel with opposite surfaces of each leg member in mutual engagement along a substantial length of each leg member, other surfaces of each leg member being provided with piezo-electric layers arranged to deflect each leg member away from the other respective leg member; wherein the rotation of the roller member generates at least one axial vector in a first axial direction along said rod whereby to cause movement of the carriage along the rod in said first axial direction.