Patent ID: 6983669

Claim:
A ball screw comprising: an elongated screw formed with a female thread; a nut formed with a complementary female thread; a series of bearing balls interposed between said screw and nut and in rolling engagement therewith within said both of said female thread turns; a ball return tube mounted to holes in said nut for receiving said balls after passing out of said holes in said nut which balls are recirculated back into said female thread; said nut further formed with a male thread aligned with and fixed relative said female thread and located at one end of said nut, said male thread having the same lead as said screw female thread but of smaller form to thereby not be engaged therewith with said balls present in said female thread, whereby said male thread will only engage said female thread in said screw if said balls are absent to allow relative axial shifting of said screw and nut to bring said male thread into engagement with said screw female thread.