IMPROVEMENTS IN LOCK NUTS, AND IN THE MEANS OF SECURING THE SAME
Year: 1877

page_text: LETTERS PATENT to Arthur Youngman Jacobs, of Sheffield, in the County of
York, Engineer, for the Invention of "IMPROVEMENTS IN LOCK NUTS, AND
IN THE MEANS OF SECURING THE SAME.”
:
Sealed the 15th February 1878, and dated the 18th August 1877.
PROVISIONAL SPECIFICATION left by the said Arthur Youngman Jacobs
at the Office of the Commissioners of Patents on the 18th August 1877.
ARTHUR YOUNGMAN JACOBS, of Sheffield, in the County of York, Engineer.
" IMPROVEMENTS IN LOCK NUTS, AND IN THE MEANS OF SECURING THE SAME."
My Invention relates to a novel method by which nuts may be prevented from
working or shaking loose on screws, bolts, axles, or other similar articles, but which
at the same time admits of their being easily removed without damage to the screw,
threads.
In carrying out my Invention, as åpplied to fish bolts, for example, I form a
longitudinal slot from the screwed end of the bolt, crossing the threads, and, say,
about two inches in length; the depth I prefer to be about twice the depth of the
threads, and of a V shape in cross section, and I make it gradually deeper to the
end nearest the head of the bolt, and terminating in a shallow recess. I also form
across the threads of the nut one or more similar slots, but where a square nut is
used I prefer 4 slots, so that a quarter turn of the nut brings one of the four slots
opposite to the slot formed in the bolt.
I further provide a cotter, key, or pin, either solid or split, but by preference I
use a split steel cotter, the cross section of which corresponds, or nearly so, to the
opening formed by the two before-mentioned slots. One arm of the cotter is longer
than the other, and is slightly hooked outwards at the end, the shorter arm being
about the length of the nut.
When the nut is screwed up it is so adjusted by a quarter turn that one of the
slots is brought opposite to the slot in the bolt, the split cotter is then inserted in
the opening formed by the combination of the two slots, the long hooked arm being

page_text: next to the bolt and forced forward. The deepening slot allows the split cotter to
expand, and the hooked end is forced into the recess at the end of the slot, as
before described, which effectually prevents the cotter from shaking loose, or from
being withdrawn, without the use of considerable force; at the same time the cotter
acts as a key and prevents the nut from turning round in either direction.
It is obvious that my Invention may be modified in its details; as, for example,
the bottom of the slots may be made of a round or square shape, and round or
square keys or cotters may be used to correspond, without departing from the
principle of the Invention.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Arthur Youngman Jacobs in the Great Seal Patent Office on the 18th
February 1878.
ARTHUR YOUNGMAN JACOBS, of Sheffield, in the County of York, Engineer.
"IMPROVEMENTS IN LOCK NUTS, AND IN THE MEANS OF SECURING THE SAME."
My said Invention relates to a novel method by which nuts may be prevented
from working or shaking loose on screws, bolts, axles, or other similar screw-
threaded articles, but which at the same time admits of their being readily removed
without damage to the screw threads.
In carrying out my said Invention, as applied to fish bolts, for example, I form a
longitudinal groove from the screwed end of the bolt, crossing the threads, and, say,
about two inches in length, and, by preference, of a depth about twice that of the
threads, and of a V shape in cross section, and I make it gradually deeper to the
end nearest the head of the bolt, and terminating in a shallow recess. I also form
across the threads of the nut one or more similar grooves, but where a square nut
is used I prefer four grooves, so that a quarter turn of the nut brings one of the
four grooves opposite to the groove formed in the bolt.
I further provide a cotter, key, or pin, either solid or split, but by preference I
use a split steel cotter, the cross section of which corresponds, or nearly so, to
the opening formed by the groove in the bolt, and the groove, or one of the
grooves in the nut. One arm of the cotter is longer than the other, and is slightly
hooked outwards at the end, the shorter arm being about the length of the nut.
When the nut is screwed up it is so adjusted by a quarter turn that its groove,
or one of its grooves, as the case may be, is brought opposite to the groove in the
bolt, the split cotter is then inserted in the opening formed by the combination of
the two grooves, the long hooked arm being next to the bolt and forced forwards.
The deepening groove allows the split cotter to expand, and the hooked end is
forced into the recess at the end of the groove, as before described, which effectually
prevents the cotter from shaking loose, or from being withdrawn, without the use
of considerable force; at the same time the cotter acts as a key so as to obviate all
liability of the nut turning in either direction.
It is obvious that two or more grooves may be provided in the bolt, and a corre-
sponding number of cotters be employed, if desired.
And in order that my said Invention may be fully understood I shall now
proceed more particularly to describe the same, and for that purpose shall refer to

page_text: the several Figures on the annexed Sheet of Drawings, the same letters of reference
indicating corresponding parts in all the Figures.
Figure 1 of my Drawings represents a sectional elevation of a bolt and nut, con-
structed and fitted according to my said Invention, for the purpose of enabling the
nut to be secured when screwed up; and Figure 2 is an end view of the same,
corresponding to Figure 1.
Figures 3 and 4 represent respectively a sectional elevation and plan of the bolt
separate from the nut.
Figure 5 represents an end view of the nut detached; and Figure 6 shews in
detail one form of cotter, key, or pin employed for securing the nut.
A is the bolt, having formed therein across the threads a longitudinal groove a,
gradually increasing in depth from one extremity 1, to the other extremity 2, where
it terminates in a shallow recess. B is the nut, formed with internal longitudinal
grooves b, arranged across its threads, and forming the counterpart of the groove a
in the bolt A, so that after the nut has been tightened up in the usual manner by
simply turning the nut for a portion of a revolution until one of the grooves b is
brought opposite the groove a in the bolt, as shewn most clearly in Figure 2, an
opening is formed for the introduction of the cotter C, represented detached in
Figure 6. The grooves a, b, are, by preference, made of a V section, as shewn, and
the cotter, which is double or split so as to form two arms c, c', of unequal length,
has each of the said arms made of a sectional form, similar to that of the groove
with which it corresponds. At the outer end of the cotter there is formed a
head c² by the union of the two arms c, c¹, and the other extremity of the longer
arm (c) is provided with a look at c, which latter when the cotter C is driven into
its place enters the recess at 2 in the bolt A, the expansion of the cotter in the
deepening groove preventing its displacement or withdrawal without the exertion
of considerable force, whilst the cotter acts as a key to secure the nut from turning
in either direction.
Having now described and particularly ascertained the nature of my said Inven-
tion, and one manner in which the same is or may be used or carried into effect,
I would observe in conclusion that I do not confine myself to the precise details
herein-before described, and illustrated on the accompanying Drawings, as the
same may be modified without departing from the principle of the said Invention,
for example, the grooves may be made of a rounded or square shape, and round or
square keys or cotters, and either split or otherwise, may be used, to correspond
therewith; but what I consider to be novel and original, and therefore claim as
the Invention secured to me by the herein-before in part recited Letters Patent is,
the combination with a bolt or other like screw-threaded article and nut, each
formed with a longitudinal groove or grooves, of a cotter, key, or pin, engaging in
the groove, or one of the grooves, of both the bolt or other like article and the nut,
the said grooves being formed, and the cotter, key, or pin constructed, substantially
in the manner and for the purposes herein-before described.
•
In witness whereof, I, the said Arthur Youngman Jacobs, have to this my
Specification set my hand and seal, this Eighteenth day of February, One
thousand eight hundred and seventy-eight.
ARTHUR YOUNGMAN JACOBS. (L.S.)