Year: 1888

page_text: Date of Application, 1st May, 1888
Complete Srecification Left, 1st Feb., 1889
Complete Specification Accepted, 23rd Mar., 1889
I, JOHN ROBERT HARGROVE, of Vernon Place, 68, Alfred Street, Sparkbrook,
Worcestershire, Malleable Ironfounder, do hereby declare the nature of this invention
to be as follows:-
This invention consists in the improvements in or connected with lock-nuts herein
described the objects being to so arrange a nut and its washer that when the nut has
been screwed home against the washer it cannot shake loose or become unscrewed and
in case of the washer breaking the parts thereof will not fall away.
In carrying out my invention I form a projecting cycloidal screw thread on that
face of the washer which is next to the face of the nut which thread takes into a corre-
The ends of the thread
sponding recessed screw thread on the said face of the nut.
form stops so that when the nut and washer are placed together and one of them is
turned the other will be turned also.
When the nut above described has been screwed home along its bolt against the
said washer the latter is by the screw threads engaging together carried round
with the nut which also prevent the nut becoming loose on the bolt and turning in the
opposite direction without turning the washer also which latter is prevented from
turning by its underside being made of large area so as to present a large frictional
surface to the surface against which it is pressed by the nut. The washer is by
preference formed with flat sides so that it can be turned by a spanner to facilitate
unlocking the nut. In case the washer should break the parts would not fall away
but would be held in place by the projecting and recessed screw threads engaging
together.
The projecting screw thread may be formed on the face of the nnt and the recessed
screw thread on the face of the washer instead of vice versa as above described. The
screw threads are by preference made the opposite hand to the thread inside the nut.

page_text: Instead of employing screw threads as above described projecting parts may be
formed on either the nut or the washer to engage in corresponding holes in the
other of them these projecting parts being so arranged as to cause the nut and
washer to turn together and prevent the parts of the washer falling away in case it
should break.
COMPLETE SPECIFICATION.
Improvements in or Connected with Lock-nuts.
I, JOHN ROBERT HARGROVE, of Vernon Place, 68, Alfred Street, Sparkbrook,
Worcestershire, Malleable Ironfounder, 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 consists in the improvements in or connected with lock-nuts herein
described the objects being to so arrange a nut and its washer that when the nut has
been screwed home against the washer it cannot shake loose or become unscrewed
and in case of the washer breaking the parts thereof will not fall away.
In carrying out my invention I form a projecting cycloidal screw thread on that
face of the washer which is next to the face of the nut which thread takes into a
corresponding recessed screw thread on the said face of the nut. The ends of the
thread form stops so that when the nut and washer are placed together and one of
them is turned the other will be turned also.
When the nut above described has been screwed home along its bolt against the said
washer the latter is, by the screw threads engaging together, carried round with the
nut which also prevent the nut becoming loose on the bolt and turning in the opposite
direction without turning the washer also which latter is prevented from turning by
its underside being made of large area so as to present a large frictional surface to
the surface against which it is pressed by the nut. The washer is by preference
formed with flat sides so that it can be turned by a spanner to facilitate unlocking the
nut. In case the washer should break the parts would not fall away but would be
held in place by the projecting and recessed screw threads, engaging together.
The projecting screw thread may be formed on the face of the nut and the recessed
screw thread on the face of the washer instead of vice versa as above described.
The screw threads are by preference made the opposite hand to the thread inside
the nut.
On the accompanying drawing Fig. 1 represents in elevation a nut and washer
constructed according to this invention; Fig. 2 ia an inverted plan of the nut and
Fig. 3 is a plan of the washer; Fig. 4 represents in section the said nut and washer
together in position on a bolt; Fig. 5 represents in elevation and in plan a modified

page_text: form of the washer provided with a triple screw thread and Fig. 6 shews similar
views of the nut for use with the same; Fig. 7 represents a slightly modified form
of the nut and washer illustrated by Figs. 1, 2, 3 and 4; Fig. 8 is an inverted plan
of the nut and Fig. 9 is a plan of the washer of the same separately.
The same letters of reference indicate the same parts in all the Figures.
Referring firstly more particularly to Figs. 1, 2, 3 and 4, A is the nut and B is its
washer. The hole in the washer B is not screw threaded. In this example of my
invention a double screw-thread 6 is employed on the washer which projects from
the face thereof and may be either of cycloidal, epicycloidal or hypocycloidal form or
other curve which will give a screw thread or threads curving outwardly from the
centre of the washer towards its periphery. The surface of this screw thread is
rounded or tapered off as seen more clearly by Fig. 4. a a are the recessed screw
threaded surfaces on the underside of the nut corresponding with the threads b b.
The screw threads aa on the nut are partly cut away so as to reduce their frictional
surface considerably below that of the underside of the washer B. The wider ends b¹¹
of the screw threads bb and the ends a¹ a¹ of the screw threads a a abut together
when the nut is screwed home along its bolt so that the washer will be carried round
by the nut until screwed up quite tightly; it will then be found that the nut
is locked and prevented from becoming loose, as any tendency to unscrew the
nut without turning the washer also causes the parts a of the nut to ride upon the
projections b of the washer which latter, by curving outwardly from the centre towards
the periphery, jam the nut between the washer and the screw threads of the bolt.
The nut is readily unscrewed from the bolt by turning the washer with it. If when
the nut A is screwed up the washer B should break, the parts of the washer would
not fall away but are retained in position by the projecting parts b engaging with the
parts a as will be seen by Fig. 4.
It will be evident that instead of employing (as illustrated by Figs. 1, 2 and 3)
double screw threads on the face of the washer and corresponding parts a on
the face of the nut, single screw threads of similar form may be used for the same
purpose, or there may be three or more threads 6 on the washer and corresponding
parts a on the nut, for instance as illustrated by Figs. 5 and 6, and that the screw
threads 6 may be formed on the nut and corresponding parts a on the washer instead
of vice versa as above described and illustrated on the drawing.
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 :-
The improved means of locking a nut by its washer hereinbefore described and
illustrated by the accompanying drawing; that is to say, making on the washer a
screw thread or screw threads b, either coned or rounded, curving outwardly towards
the periphery and a corresponding surface or surfaces a on the nut, substantially as
and for the purposes set forth.
Dated this 21st day of January 1889