Ball screw mechanism with integral opposing thread
AssigneeAtwood Mobile Products, Inc.
InventorsPatrick Clint, Bryce J. Bulthaus, Stephen Caronna
Life of this patent
Estimating the term…
Abstract
A ball screw mechanism has an opposing thread provided by an integral male thread formed at one end of a nut received on the screw. The male thread is of a smaller form than the female thread on the screw so as to not normally be in contact therewith, but should ay loss of the balls occur with the resultant slight relative axial shift of the screw and nut, the male threads engage to limit such relative axial movement to protect connected equipment. Both the nut male and female threads may be machined from a cylindrical nut blank.
Claims20
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 rolling 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 on holes in said nut which balls are recirculated back into said female thread;
- said nut further formed with a male thread aligned with 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 normally not be engaged therewith when said balls are present in said female thread, said male thread only engaging said female thread in said screw when 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.
A ball nut and screw assembly comprising, in combination:
- a screw having an outer surface including a female thread;
- a nut received on the screw, the nut formed with a female thread complementary to the female thread of the screw and having a pair of apertures at opposite ends of said female thread;
- a plurality of balls disposed between the nut and the screw, each of the plurality of balls extending partially into the female thread of the screw and the female thread of the nut;
- a ball return tube connected to the pair of apertures for receiving the balls which pass out one of said apertures and are thereby recirculated back into the other aperture;
- the nut formed with an integral male thread aligned with the female thread of the nut adjacent one end of the nut, the male thread having the same lead as the female thread of the screw but smaller in form so as not to be normally engaged therewith when the balls are present in the female threads, the male thread in the nut engaging the female thread in the screw only when the balls are absent allowing relative axial movement of the screw and nut sufficient to engage said male thread with said screw female thread.
A method of manufacturing a ball screw comprising the steps of:
- forming a screw with a female thread;
- forming a nut to be fit onto said screw with a complementary female thread;
- forming said nut with a male thread aligned at one end of said female thread and configured to be aligned within said female thread of said screw with said nut on said screw, said male thread formed to be of smaller form so as to not normally engage said female thread of said screw when said female threads on said nut and screw are aligned;
- and
- assembling a series of balls in said aligned nut and screw female threads to provide rolling support of said nut on said screw and prevent engagement between said nut male thread and screw female thread.
Dependencies are inferred from the claim text.