IMPROVEMENTS IN THE MEANS OF LOCKING SCREW NUTS
Year: 1867

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in
the County of Middlesex, for the Invention of "IMPROVEMENTS IN THE
MEANS OF LOCKING SCREW NUTS."-A communication from abroad by
Charles Bouchacourt, Civil Engineer, of 29, Boulevart St. Martin,
Paris.
Sealed the 22nd October 1867, and dated the 3rd May 1867.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents, with his Petition, on the
3rd May 1867.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN THE MEANS OF LOCKING SCREW NUTS," to be as follows:-
This Invention relates to a means of preventing the loosening of screw nuts.
The improvements consist in locking the nut on the part which is to be held
thereby, for which purpose I groove both the nut and the part in contact with
it at one or more points. After the nut is tightened up a small pin or key is
introduced to fill up the space presented by the two superposed grooves; this
small pin or key being thus lodged partly in the groove of the nut and partly
in that of the part to be fixed entirely prevents the nut from becoming loose..
The pin may as a precaution be bent at right angles at the end forming a
head received in a space made in the part to be fixed, and in this case I bend:

page_text: the key in order to facilitate its introduction, and on being driven into
position by the blow of a hammer it will be again straightened, and the head
will lodge in the bottom of the recess; the pin will then be in position, and
the nut will be locked to the part it fixes. In order to unfix the nut in case
it is impossible to withdraw the pin it is simply necessary to force it with a
wrench, to facilitate which the pin may be made of soft iron or other metal or
material of sufficient strength. If the pin be made of steel its elasticity would
permit of its being readily placed in position and withdrawn without putting it
out of shape. In some cases the locking might be effected without a groove
being made in the part to be fixed by simply having a hole made therein.
Where the nuts are employed for fixing the fish plates of rails it is sufficient,
for example, to make a single groove throughout the length of the plate, and
one or two small holes at each bolt hole, while the nut is provided with three
or six grooves if a six-sided nut be used. Sometimes an elastic medium,
such as india-rubber, is interposed between the nut and the part to be fixed,
in which case the locking above described is arranged as follows:-The key is
fixed or formed either on the nut, on the washer, or on the part to be fixed; it
might, for example, project from one or other of the three parts mentioned
and enter when the nut is completely. screwed up into one of the grooves of the
part immediately in contact.
This Invention is illustrated in the accompanying Drawing, Figure 1 of
which shows a side view of a screw nut with the improvements applied;
Figure 2 shows a plan of the same, with several arrangements of grooves and
holes; Figure 3 shows a central vertical section of a screw nut with the key
just entering the groove; Figure 4 shows a similar section with the key
straightened and in place. The same letters serve for all the four Figures.
a, screwed part of the bolt; b, part to be fixed provided with grooves c and
a hole d for receiving the head of the pin or key; e, nut with grooves f made on
the under side; 9, pin or key, the stem of which after the nut has been
screwed up is introduced into one of the grooves c, while the head h enters
the hole d of the part b; this latter operation, as before mentioned, is facilitated
by the straightening of the key from its original bent form.
I may as a modification of the same mode of fixing.screw nuts where there
are several in close proximity, as in a fish plate connecting rails, for example;
dispense, with a groove in the fish, plate, instead of, which the nuts, would be
provided, with grooves; and in order to lock them. one end of the key or pin
is introduced, under. a, first, nut, and, the other, end of the same key under
another nut entering one of the grooves in the same; the two чuts would be
thus solidly fixed together, and the locking effected without, grooving the fish

page_text: plate. Figure 5 shows a central vertical section of the mode of locking
according to this last arrangement. The ends of the pin or key of the bent
form shown are introduced into the opposite grooves of the two nuts, it being
then flattened with a hammer, said key so flattened on the fish plate or other
part to which the nut is applied may be of a triangular, half round, or other
form.
The Invention thus consists in the mode of locking nuts used for all
purposes by securing their inner face to the part to be fixed for the purpose
of preventing their becoming unscrewed or loose, all as herein-before
described.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Alexander Melville Clark in the Great Seal Patent Office on
the 1st November 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME; I, ALEXANDER
MELVILLE CLARK, of 58, Chancery Lane, in the County of Middlesex, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Third day of May, in the year of our Lord One
thousand eight hundred and sixty-seven, in the thirtieth year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said
Alexander Melville Clark, Her special licence that I, the said Alexander
Melville Clark, my executors, administrators, and assigns, or such others as I,
the said Alexander Melville Clark, my executors; administrators, and assigns,
should at any time agree with; and no' others, from time to time and at all
times thereafter 'during the term therein expressed, should and lawfully miglit
make, use, exercise, and vend, within the United Kingdom of Great Britain'
and Ireland, the Channel! Islands, and Isle of Man, an Invention for "IMPROVE-
MENTS IN THE MEANS OF LOCKING SCREW NUTS," a communication to me from
abroad by Charles Bouchacourt; Civil Engineer, of' 29, Boulevart St. Martin,
Paris, upon the condition (amongst others) that I, the said Alexander' Melville
Clark; my executors or administrators, by an instrument in writing under my,
or their, or one of their hands and seals, should particularly' describe and' ascer-
tain the nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date of the
Said Letters Patent.

page_text: NOW KNOW YE, that I, the said Alexander Melville Clark, do hereby
declare the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement, reference being had to the Sheet of Drawings hereunto annexed,
and to the letters and figures marked thereon (that is to say) :-
This Invention relates to a means of preventing the loosening of screw nuts.
The improvements consist in locking the nut on the part which is to be held
thereby, for which purpose I groove both the nut and the part in contact
with it at one or more points. After the nut is tightened up, with one or
more of the grooves coinciding, a small pin or key is introduced to fill up the
space presented by the two superposed grooves; this small pin or key being
thus lodged partly in the groove of the nut and partly in that of the part to
be fixed entirely prevents the nut from becoming loose. The pin may as a
precaution be bent at right angles at the end forming a head, which is
received in, a space made in the part to be fixed, and in this case I bend the
key in order to facilitate its introduction, and on being driven into position by
the blow of a hammer it will be again straightened and the head will lodge
in the bottom of the recess; the pin will then be in position, and the nut
will be locked to the part it fixes. In order to unfix the nut in case it is
impossible to withdraw the pin it is simply necessary to force it with a wrench,
to facilitate which the pin may be made of soft iron or other metal or material
of sufficient strength. If the pin be made of steel its elasticity would permit
of its being readily placed in position and withdrawn without putting it out
of shape. In some cases the locking might be effected without a groove
being made in the part to be fixed by simply having a hole made therein.
Where the nuts are employed for the fish plates of rails it is sufficient, for
example, to make a single groove throughout the length of the plate, and one
or two small holes at each bolt hole, while the nut is provided with three or
six grooves, if a six-sided nut be used, "Sometimes an elastic medium, such
as india-rubber is interposed between the nut and the part to be fixed, in which
case the locking above described is arranged as follows:-The key is fixed
or formed either on the nut, on the washer, or on the part to be fixed, it might,
for example, project from one or other of the three parts mentioned, and
enter when the nut is completely screwed up into one of the grooves of the
part immediately in contact.
This Invention is illustrated in the accompanying Drawing, Figure 1 of
which shows a side view of the screw, nut with the improvements applied;
Figure 2 shows a plan of the same with several arrangements of grooves and
holes; Figure 3 shows a central vertical section of a screw nut with the key

page_text: just entering the groove; Figure 4 shows a similar section with the key
straightened and in place. The same letters serve for all Figures.
a screwed part of the bolt; b, part to be fixed provided with grooves c and
a hole d for receiving the head of the pin or key; e, nut with grooves f made
on the screwed under side; g, pin or key the stem of which after the nut has
been screwed up is introduced into one of the grooves c while the head h
enters the hole d of the part b. This latter operation, as before mentioned, is
facilitated the straightening of the key from its original bent form.
I may as a modification of the same mode of fixing screw nuts where there are
several in close proximity, as in a fish plate connecting rails, for example,
dispense with a groove in the fish plate, instead of which the nuts would be
provided with grooves; and in order to lock them one end of a key or pin is
introduced under a first nut, and the other end of the same key under another
nut entering one of the grooves in the same, the two nuts would be thus
solidly fixed together, and the locking effected without grooving the fish plate.
Figure 5 shows a central vertical section of the mode of locking according to
this last arrangement. The ends of the pin or key of the bent form shown
are introduced into the opposite grooves of the two nuts, it being then
flattened with a hammer, said key so flattened on the fish plate or other part
to which the nut is applied may be of a triangular, half round, or other form.
It will be understood that this last-described mode of locking with two nuts
is employed, preferably, when there is only one groove in the fish plate or
other part to be fixed.
Having described the nature of this Invention, and the manner of perform-
ing the same, I declare that what I claim as the Invention to be protected by
the herein-before in part recited Letters Patent is, the mode of locking screw
nuts used for all purposes, as before described and illustrated in the Drawings
annexed, by securing their inner face to the part to be fixed so as to prevent
their loosening by means of grooves made in one or both of the surfaces in
contact as and for the purposes described.
In witness whereof, I, the said Alexander Melville Clark, have here-
unto set my hand and seal, this First day of November, in the
year of our Lord One thousand eight hundred and sixty-seven.
A. M. CLARK. (L.S.)