IMPROVEMENTS IN NUTLOCKS
Year: 1885

page_text: We, ARTHUR THOMAS ALLEN and HENRY CAVILL both of the Hallamshire
Engineering Works Arundel Street Sheffield, in the County of York, Engineers, do
hereby declare the nature of our said invention for "IMPROVEMENTS IN NUTLOCKS"
to be as follows:-
:-
Our invention relates to a method of locking nuts upon bolts or screws in such a
manner that they cannot shake loose.
In carrying out our invention, we form upon the outside face of the nut a circle
of undercut teeth, or equivalent devices such as diagonal holes, and we prepare a
loose washer having on one side a corresponding circle of teeth, or their equivalents,
the other side being plain. We make the end of the bolt for a short distance, with
one, two, or more flat sides, or of other suitable shape, the hole in the washer being
made to correspond, so that it can be put upon the bolt but cannot turn round.
When put into use the nut is screwed up to the desired position, the washer is
then passed on to the end of the bolt until the teeth engage with those on the nut;
the nut is then turned back, the points of the teeth passing under those of the nut,
in which position the nut is effectually locked.
ROBT F. DRURY,
Agent for the Applicants.

page_text: We ARTHUR THOMAS ALLEN and HENRY CAVILL both of the Hallamshire
Engineering Works Arundel Street, Sheffield, in the County of York,.Engineers do
hereby declare the nature of our invention for IMPROVEMENTS IN NUTLOCKS and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement, that is to say -
Our invention relates to a method of locking nuts upon bolts or screws, in such
a manner that they cannot shake loose, or otherwise become unscrewed.
And in order that our invention may be clearly understood we annex a sheet of
drawing, in which the same letters of reference indicate similar parts in all the
figures in which they occur.
Fig. 1, View of top side of Nut.
Fig. 2, Plan and edge of Washer.
Fig. 3, Squared end of Bolt or screw.
Fig. 4, Elevation of nut, washer, and bolt.
Fig. 5, Two views of nut-forming a modification of our invention.
Fig. 6, Plan and edge of washer.
Fig. 7, Shows the bolt with the twisted end.
Fig. 8 Plan when the nut is locked.
In carrying out our invention as shown in the figures 1. 2. 3. 4. of the drawings
we stamp cast or otherwise make the nut with a series or ring of undercut teeth A
inclining in the direction of the unscrewing movement of the nut, or other
equivalent retaining devices, such. as diagonal or inclined holes or indentations,
formed in or upon the outer face or top of the nut, and we prepare a washer with
corresponding teeth B, or equivalent retaining devices formed either in the edge or
upon the underside of the washer, and inclining in the opposite direction to those
on the nut.
A portion of the bolt or screw (usually the end C) is squared as shown in Fig. 3,
or is otherwise shaped so as to prevent the washer from turning round upon it the
hole in the washer being. made to correspond with and fit over or upon the said
squared or shaped part of the bolt or screw.
It follows that when the nut is screwed on the bolt to the desired position, with
the end of the bolt projecting through its outer face, and the washer is passed upon
the said end, if the teeth of the washer engage with those of the nut then the nut
cannot be unscrewed.
To prevent the washer being shaken, drawn, or forced out of its position a slight
turn of the nut backwards brings the points of the washer teeth in close engage-
ment with and under those of the nut, it is therefore impossible for the nut to
become accidentally unscrewed.
To release the washer and unscrew the nut it is necessary first to tighten or
screw up the nut until the teeth can be disengaged and the washer can then be
drawn back.
In the modification of our invention shown in Figs 5. 6. 7. 8. undercut teeth are
dispensed with, and parallel teeth on their equivalents are used.

page_text: To retain the washer in close connection with the nut, and prevent it being
shaken loose, we make the end of the bolt or screw square (by preference) and we
twist it so as to form a spiral, or we may form the spiral by cutters or by other
means.
The hole in the washer is made to fit upon or over the twisted or spiral end of
the bolt, thus it will follow the course of the spiral as it is passed over it, but
cannot be withdrawn when prevented from turning.
To lock the nut, the washer is passed on the spiral end of the bolt until it
engages with the nut; the nut is then turned back a little to tighten the parts
together. To become loose the washer must have a straight or direct movement
until clear of the parallel teeth of the nut, this is impossible oweing to the spiral of
the bolt end on which it also fits, it is therefore securely locked.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is
1st The method of securing or "locking" nuts upon their bolts or screws, by the
use of a toothed or indented washer, fitting upon a squared or otherwise shaped
part of the bolt or screw, (in such a manner that it cannot turn round,) and
engaging with undercut teeth (or their equivalents) formed in or on the outer
face or top of the nut, substantially as hereinbefore described and illustrated in
Figs 1. 2. 3. 4.
2nd The method of securing or "locking" nuts upon their bolts or screws, by
the use of a toothed washer, fitting upon a twisted or spirally formed end of the
bolt or screw and engaging with corresponding teeth formed on the top or
outer face of the nut, substantially as herein before described and illustrated in
Figa 5. 6. 7. 8.
D