Improvements in Lock Nuts and Washers.
Year: 1889

page_text: Date of Application, 18th Oct., 1889
Complete Specification Left, 18th July, 1890-Accepted, 23rd Aug., 1890
PROVISIONAL SPECIFICATION.
Improvements in Lock Nuts and Washers.
I, RICHARD BRADSHAW of Ivy Cottage, Swinton, in the County of Lancaster,
Mechanical Engineer do hereby declare the nature of this invention to be as
follows:-
The object of this invention is to provide for the locking of nuts-such as the
nuts of fish-plate bolts and the like to prevent them turning back or unscrewing
after being tightly screwed up into place without the exertion of considerable force.
I form the nut with a series of rasp or file like teeth cut on one side which will
cut into the plate or washer against which it is screwed; or where the washer can be
placed so as not to turn with the nut the washer may on one or both sides be cut
with such teeth, which will cut into the nut. These teeth must be cut so as to
incline in the same direction as that in which the nut turns when being screwed up
tight. Thus when the nut is tightly screwed up the teeth on either the nut or
washer will embed themselves into the other and will prevent the movement of the
nut in the reverse direction without the application of considerable force.
The exact form or shape of the teeth is not essential so that they will allow of the
screwing up of the nut without much resistance and at the same time will act -to
prevent the unscrewing or slackening of the nut when not desired from mere
vibration or other similar cause.
Dated this 17th day of October.
WM. P. THOMPSON & Co.,
6, Bank Street, Manchester, Patent Agents.
COMPLETE SPECIFICATION.
Improvements in Lock Nuts and Washers.
I, RICHARD BRADSHAW of Ivy Cottage, Swinton, in the County of Lancaster,
Mechanical Engineer, 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 :-
The object of this invention is to provide for the locking of nuts-such as the
nuts of fish-plate bolts and the like to prevent them turning back or unscrewing
without the exertion of considerable force after being tightly screwed up into place.
It consists essentially in forming the nut or washer with a series of rasp or file
like teeth or other serrations cut on the side against which the pressure of the nut
is exerted when screwed up tight.
It will be fully described with reference to the accompanying drawings in which
a fish plate bolt with washer and square nut are shown.
Fig. 1 elevation of bolt and nut.
Fig. 2 plan of under side of nut.
Fig. 3 plan of washer.
I form the nut A, or the washer B, with a series of serrations preferably in the
form of rasp or file like teeth a cut in the case of the nut on the side which bears
against the plate or washer and in the case of the washer on one or both sides. These
teeth must be cut so as to incline in the same direction as that in which the nut
turns when being screwed up tight.
It is not intended to use at the same time a nut and washer both constructed alike
but where the nut is serrated the serrated washer may be dispensed with or a washer
with one serrated side only will be used in which case the serrated side will be turned
away from the nut so as to engage with the plate against which it is screwed to

page_text: prevent it turning with the nut. Where the serrated washer is used the nut may be
an ordinary one and the washer preferably serrated on both sides the serrations on
one side to engage with the nut and those on the other side to engage with the plate
to prevent the washer turning round with the nut. The nut and washer may be of
any suitable shape or number of sides.
When the nut is tightly screwed up the teeth on either the nut or washer will
embed themselves into the other and will prevent the movement of the nut in the
reverse direction without the application of considerable force.
The exact form or shape of the teeth or serrations is not essential so that they will
allow of the screwing up of the nut without much resistance and at the same time
will act to prevent the unscrewing or slackening of the nut when not desired from
mere vibration or other similar cause. The teeth or serrations may for instance radiate
like single file cuts from the centre or may be cross cut like an ordinary file but at
present I prefer the rasp cut teeth.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is :-
-
1. A nut cut with rasp or file like teeth or other similar serrations on the under
side to lock it and prevent it unscrewing when tightly screwed up substantially as
described.
2. A washer cut with rasp or file like teeth or other similar serrations on one or
both sides substantially as and for the purposes described.
WM. P. THOMPSON & Co.,
Manchester, Liverpool, and London, Patent Agents.
WM. P. THOMPSON & Co.,
Manchester, Liverpool, and London, Patent Agents.