An Improved Lock-nut and Bolt.
Year: 1893

page_text: Date of Application, 19th Apr., 1893-Accepted, 10th June, 1893
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An Improved Lock-nut and Bolt.
I, JOHN HORACE O'BRIEN of East St. Kilda, in the Colony of Victoria,
Mechanic, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
This invention provides a simple method of and apparatus for locking a nut on
a bolt and is devised for the purpose of preventing the unscrewing or slackening
back of a nut which frequently occurs owing to the vibration to which the bolt and
nut are subjected.
Various means have been devised for locking a nut on a bolt, but while my
invention is perfectly efficient, it is simpler and more economic than many of these,
whilst an additional advantage is that it may be easily applied to existing bolts
and nuts.
The invention consists in forming a collar on a nut and a flat or groove on a
bolt in such a manner that when the nut is screwed up it may be locked by applying
a blow from a pointed hammer or other tool on to the collar directly over the flat
or groove the said collar being thus made to squeeze or close on the flat or into the
groove so as to form a key which will prevent the nut unscrewing. The nut in
this way may be locked on any part of the bolt along the thread.
I will now refer to the drawings in which-
Fig. 1 is a view of my improved bolt and nut shewing the nut in its locked
position.
Figs. 2, 3, and 4 are views of sections through the bolt shewing the flat and also
shewing different forms for the groove.
Fig. 5 is a longitudinal view shewing the collar.
Fig. 6 is also a longitudinal view shewing an alternative method of forming the
collar on the nut.
In these drawings "A "is the groove which may be of curved form (as in
Fig. 2) or V shaped (as in Fig. 4), but I prefer to simply take out or flatten a
portion of the periphery (as in Fig. 3). The groove or flattened portion is extended
preferably the length of the thread. I do not confine myself to these particular
sections for the groove as various shapes may be employed. A thin projecting
collar "C" is formed on the ordinary nut "D"; this collar may be threaded in
continuation of the thread of the nut (as in Fig. 5) or may simply lie against
the surface of thread of the bolt.
An alternative method of forming the collar (see Fig. 6) consists in forming
an annular groove "E" on the nut. The advantage of this form is that it may
be applied to existing nuts and as the existing bolts may also be grooved the
whole invention may thus be applied to existing bolts and nuts. If after locking
the nut in the manner before described it is afterwards found to require screwing
or unscrewing this may be done by the use of a very strong spanner, sufficient
force being applied to rebend the misshapen collar.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. In lock nuts a nut provided with a projecting collar as "C" to encircle
the thread of a bolt as and for the purposes described.
2. In lock nuts-an annular groove cut in the nut so as to form a collar thereon
as and for the purposes described.
3. In lock nuts-a bolt provided with a groove or having a portion of its

page_text: periphery flattened, said groove or flattened portion extending the length of its
thread as and for the purposes described.
4. In lock nuts-the combination of a nut having a collar as "C" with a bolt
having a groove as "A" as and for the purposes described.
Dated this 10th day of April 1802
J. H. O'BRIEN.
W. H. Beck,
Per S. E. Gunyon,
115, Cannon Street, London, E.C., Agent.