Improvements in Devices for Securing or Locking Screw Nuts.
Year: 1888

page_text: Date of Application, 12th Dec., 1888
Complete Specification Left, 10th Sept., 1889-Accepted, 19th Oct., 1889.
PROVISIONAL SPECIFICATION.
Improvements in Devices for Securing or Locking Screw Nuts.
I, HOWARD PULLAR, of Rockvale Villa, Bridge of Allan, in the County of Stirling,
North Britain, Engineer, do hereby declare the nature of this Invention to be as
follows, that is to say :-
My said Invention has for its object by the application of improved devices to
prevent the loosening of screw nuts, or to diminish their liability to unscrew.
In carrying out my Invention I form a wedge-shaped or tapering recess which has
a part of the bolt for its inner side and a part of the nut for its outer side, and in
this recess I place a ball or roller or piece of any suitable shape. When the nut is
being screwed up the actions of the nut and bolt on the ball carry it to the wider part
of the recess, and when at such part it does not obstruct the screwing up of the
nut, but when the nut turns in the unscrewing direction the ball is moved into the
narrower part of the recess and has a jamming action between the nut and the bolt.
When it is wished to remove the nut a small instrument may be inserted to keep
the ball at the widest part of the recess or to pick it out altogether.
The recess may be formed entirely in the nut, its side being made in the shape of
more or less of a circle eccentric to the axis of the bolt and nut; and the ball may
bear against the threads of the bolt or against a part of the bolt made without a
screw thread. Or the recess may be formed entirely in the side of the bolt. If
necessary the recess may be undercut to prevent the ball from getting out accidentally;
and if required a spring may be applied to push the ball so far towards the narrow
end of the recess so as to insure its being in contact with the bolt and nut on its
inner and outer sides. When a roller is applied instead of a ball it may be grooved
to engage with the threads of the bolt or with those of the nut.
Dated this Eleventh day of December 1888
EDMUND HUNT,
Annlinnt's & meant
COMPLETE SPECIFICATION.
Improvements in Devices for Securing or Locking Screw Nuts.
I, HOWARD PULLAR, of Rockvale Villa, Bridge of Allan, in the County of Stirling,
North Britain, 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, that is to say :-
My said Invention has for its object, by the application of improved devices to
prevent the loosening of screw nuts, or to diminish their liability to unscrew.
In carrying out my Invention I form a curvilinear wedge-shaped or tapering
recess which has a part of the bolt for its inner side and a part of the nut for its
outer side, and in this recess I place a ball or roller or piece of any suitable shape.
When the nut is being screwed up the actions of the nut and bolt on the ball carry
it to the wider part of the recess, and when at such part it does not obstruct the
screwing up of the nut, but when the nut turns in the unscrewing direction the ball
is moved into the narrower part of the recess and has a jamming action between
the nut and the bolt. When it is wished to remove the nut a small instrument may
be inserted to keep the ball at the widest part of the recess or to pick it out
altogether. Two or more. curvilinear wedge-shaped recesses may be made in one
nut so that the ball may be placed in whichever is most suitable. Thus in the case
of a horizontal bolt the ball can be placed in that one of the recesses in which its
weight will press it towards the narrow end. When it is wished to prevent un-
screwing in either direction the nut may be made with reversed recesses and a ball
may be placed in each. A spring may be applied to tend to move a ball towards the

page_text: narrow end of its recess; and when desired the ball or balls may be attached to
wires or be otherwise prevented from being dropped or easily lost.
And in order that my said Invention and the manner of performing the same may
be properly understood I hereunto append a sheet of explanatory drawings to be
hereinafter referred to and representing various examples of my improved nut-lock
devices. In these drawings the same reference letters are used to mark the same or
like parts wherever they are repeated.
In a first modification, shown in end view in figure, 1, and in sectional elevation
in figure, 2, the bolt, A, is not in any way made different. from an ordinary bolt,
and the tapered recess, B, is formed entirely in the nut, C. The recess, B, is
undercut or made sufficiently narrower at its outer edge to prevent the ball, D,
from getting out except at the wider end of the recess where the overhanging edge
is recessed a little to allow of the easy introduction of the ball. A small spring, E,
is shown as inserted so as to slightly press the ball, D, towards the narrow end of the
recess, B. This recess, B, is by preference so formed in relation to the screw threads
as that the ball, D, may bear on two threads and not on only onc.
In a second modification shown in end view in figure, 3, and in sectional elevation
in figure, 4, the ball, D, has a hole bored through it and it is retained by a headed
wire, F, which is loose in the hole in the ball and is screwed into a small tapped bore
at the bottom of a larger bore, G, formed in the nut downwards from the recess, B.
The bore, G, being larger than the wire, F, allows the ball to move along the
recess, B; and the wire may have a spring set imparted to it to make it press the ball
towards the narrow end of the recess. A small washer is placed under the ball and
over the bore, G, to prevent the ball from getting partly into the bore.
In a third modification shown in end view in figure, 5, the recess is made with
reversely tapered parts (or there may be two separate reversely tapered recesses) to
receive two balls, D, D, for the purpose of preventing the nut, C, from turning in
either direction. The two balls, D, D, bored and strung on a wire, H, of the form
shown in figure, 5, and separately in figure, 6. The wire has a spring set imparted
to it tending to make its circular part close in and to thereby press the two balls, D, D
towards the narrow parts of their respective portions of the recess, B.
In a fourth modification shown in sectional clevation in figure, 7, the ball, D, does
not bear against the screw threads of the bolt, A, but on a part of the bolt at the
end made without threads.
In a fifth modification, shown in sectional elevation in figure, 8, and in end view
in figure, 9, the recess, B, is formed entirely by cutting away a tapered segmental
part of the bolt, A.
In a sixth modification, shown in sectional elevation in figure, 10, and in end view
in figure, 11, the recess, B, is produced by forming a pin, J, of reduced diameter
eccentrically on the bolt end thereby obtaining a recess the two halves of which taper
in opposite directions.
In a seventh modification shown in sectional elevation in figure, 12, and in end view
in figure, 13, three recesses, B, B, B, are formed in the nut, C, and uniting with each
at the narrow parts by boring out three separate circular portions, each recess having
its halves tapered opposite ways.
Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed, 1 declare that what I
claim is :-
The improved devices for securing and locking screw nuts the essential features
of which is the application of a ball, roller, or piece of any suitable shape, in a
curvilinear wedge-shaped or tapering recess which has a part of the bolt for its inner
side and a part of the nut for its outer side, substantially as hereinbefore described.
Dated this Ninth day of September 1889.
EDMUND HUNT,
Applicant's Agent.