Patent ID: 7013747

Claim:
A ball screw and nut assembly including a screw having, on its exterior circumference, one or more continuous helical grooves and lands and a unitary nut having, in its interior circumference, at least one complementary, helical groove section, the nut being configured to rotate on said screw to achieve lateral movement along a major axis of said screw, said assembly comprising: (a) a plurality of bearing balls retained and under load between the grooves of said screw and said complementary grooves of the nut and forced to move in a forward direction along said major axis on a path formed by the grooves of the screw and nut to facilitate rotation of said nut about said screw; and, (b) internal recirculating means formed within a portion of each interior groove of the unitary nut having sufficient depth and structure different from the rest of that groove, said internal recirculating means allowing for movement of said bearing balls in a reverse direction along said major axis by sliding said bearing balls over at least one land between the adjacent grooves of said screw.