Patent ID: 7677126

Claim:
A ball screw mechanism comprising: a screw having a first axis and at least one screw groove extending along a first helical path about said first axis; a nut having a first aperture receiving said screw and having at least one nut groove extending along a second helical path about said first axis between first and second edges disposed on opposite sides of said screw wherein said at least one screw groove and said at least one nut groove are aligned and cooperate to form a helical passageway extending at least 180 degrees about said first axis between a first opening at said first edge and a second opening at said second edge; a plurality of balls moving, in part, along said helical passageway; and an external ball nut return radially spaced from said screw and extending at least partially around said nut between a first end having an opening communicating with said first opening and a second end having an opening communicating with said second opening to circulate said plurality of balls with respect to said helical passageway, a non-enclosed channel defined in said external ball nut return that extends between said first and second end openings.