IMPROVEMENTS IN BOLTS, NUTS, AND WASHERS
Year: 1868

page_text: LETTERS PATENT to Henry Chapman, of No. 2, Westminster
Chambers, Westminster, in the County of Middlesex, Civil
Engineer, for the Invention of "IMPROVEMENTS IN BOLTS, NUTS, AND
WASHERS"
Sealed the 28th July 1868, and dated the 31st January 1868.
PROVISIONAL SPECIFICATION left by the said Henry Chapman at the
Office of the Commissioners of Patents, with his Petition, on the
31st January 1868.
I, HENRY CHAPMAN, of No. 2, Westminster Chambers, Westminster,
in the County of Middlesex, Civil Engineer, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN BOLTB, NUTS, AND
WASHERS," to be as follows:-
My Invention has reference to a new method of preventing the
slackening or unscrewing of bolts and nuts or of screwed bolts, which
commonly takes place from the jarring or vibration of those parts of
a structure or machine in which they are employed. It consists in
forming upon the bearing surface either of the nut or of the washer
that is interposed between this and the object which it secures, or
[Price Sd.]

page_text: upon the head of the bolt, or upon all or any of these surfaces,
serratious, corrugations, indentations, or projections, so formed that while
they offer no obstruction to the screwing or tightening up of the nut
or bolt head they will by indenting themselves into the substance of
the other meeting surface against which they bear effectually provent
the turning of the nut or bolt head in the reverse direction so as to
become slackened or unscrewed. I prefer to employ for this purpose
washers made of hardened steol, or generally speaking of a material
harder than the nuts or bolt heads and flanges or other surfaces between
which the washers are interposed, upon both surfaces of which washers
I form file-like serrations in a more or less radial direction, but with
the edges of the serrations on the one surfaco lying in the opposite
direction to those of the serrations on the other surface. In some cases
it may be sufficient to form such serrations upon one face only of the
washer. It will be self-evident that in the case of using the serrations
upon the nut or bolt head without the interposition of a washer, such
nut or bolt head must also be made of a material harder than that of
the surface against which it bears. The form of the serrations,
corrugations, indentations, or projections may be variously modified;
thus they may be formed of small dimensions and close together, like
those of a file, or they may be formed larger and deeper as a series of
inclined planes with sharp edges, similar to the face of a tool, known as
"rose cutter;" or again they may be formed like the teeth of a
rasp, or they may be of any other form that will accomplish the purpose
of my Invention, namely, that of allowing the nut to be turned in the
direction for screwing or tightening up, but preventing its turning in
the contrary direction.
a
My Invention is applicable and of great utility in all cases in which
parts of a structure are firmly connected together by means of bolts and
nuts or screwed bolts, and particularly in those cases in which the parts so
connected are subject to irregular strains or to a vibratory action, as, for
example, the girders of buildings, the segments of arches, the framework
and moving parts of machinery, and the fish plates to the rails of the per-
manent way of railways.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said Henry Chapman in the Great Seal Patent Office
on the 30th July 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
CHAPMAN, of No. 2, Westminster Chambers, Westminster, in the
County of Middlesex, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirty-first day of January, in the year
of our Lord One thousand eight hundred and sixty-eight, in the thirty-
first year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Henry Chapman, Her special licence that I,
the said Henry Chapman, my executors, administrators, and assigns, or
such others as I, the said Henry Chapman, 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 might make, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and Isle
of Man, an Invention for "IMPROVEMENTS IN BOLTS, NUTS, AND WASHERS,"
upon the condition (amongst others), that I, the said Henry Chapman,
my executors or administrators, by an instrument in writing under my,
or their, or one of their hands and scals, should particularly describe
and ascertain 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.
NOW KNOW YE, that I, the said Henry Chapman, 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 thereof, reference being had to the accompanying
Sheet of Drawings, and to the figures and letters marked thereon, that is
to say:-
My Invention has reference to a new method of preventing the
slackening or unscrewing of belts and nuts or of screwed bolts, which
commonly takes place from the jarring or vibration of those parts of a
structure or machine in which they are employed. It consists in
forming upon the bearing surface or surfaces either of the nut or of
the washer that is interposed between this and the object which it

page_text: secures, or of the head of the bolt or upon all of these surfaces, serrations,
corrugations, indentations, or projections so formed that although
offering no obstruction to the screwing or tightening up of the nut
or bolt head they will by indenting themselves into the substance of
the other meeting surface against which they bear effectually prevent
the turning of the nut or bolt head in the reverse direction so as to
become slackened or unscrewed. I prefer to employ for this purpose
washers made of hardened steel, or generally speaking of a material
harder than the nuts or bolt heads and flanges or other surfaces
between which the washers are interposed, upon both surfaces of which
washers I form file-like serrations in a more or less radial direction,
but with the edges of the serrations on the one surface presenting
themselves in the opposite direction to those of the serrations on the
other surface. In some cases it may be sufficient to form such serrations
upon one face only of the washer. It will be self-evident that in the
case of using the serrations upon the nut or bolt head without the
interposition of a washer, such nut or bolt head must also be made of
a material harder than that of the surface against which it bears.
The serrations, corrugations, indentations, or projections may be variously
modified in form, thus they may be of small dimensions and close
together like those of a file or they may be formed larger and deeper as a
series of inclined planes with sharp edges similar to the face of a tool
known as a rose cutter," or they may be formed like the teeth of a rasp
or they may be of any other form that will accomplish the purpose of my
Invention, namely, that of allowing the nut to be turned in the direction
for screwing or tightening up but preventing its turning in the contrary
direction.
65
My Invention is applicable and of great utility in all cases in which the
parts of a structure are firmly connected together by means of bolts and
nuts or screwed bolts, and particularly in those cases in which the parts
so connected are subject to irregular strains or to a vibratory action, as for
example the girders of buildings, the segments of arches, the framework
and moving parts of machinery, and the fish plates to the rails of the per-
manent way of railways.
But in order that my said Invention may be perfectly understood
and readily carried into effect, I will now procced more particularly
to describe the manner of performing the same, for which purpose I
which are
will refer to the accompanying Sheets of Drawings, on

page_text: indicated some of the various modifications of which iny Invention is
susceptible.
Figure 1 shows a plan, Figure 2 shows a section, and Figure 3
shows a side view of the form of washer which I prefer generally to
employ. The washer A, made by preference of steel or case-hardened
iron, has serrations a, a, formed on both its surfaces, the edges of the
serrations on the one surface presenting themselves in the reverse
direction to those of the serrations on the other surface, as shown,
so that when the washer is interposed between the nut or the head
of the bolt, as shown at Figure 10, the edges of the serrations indenting
themselves into the softer material of which the nut, bolt, and object to be
secured are formed will effectually prevent the turning of the nut or bolt
in the direction for unscrewing, but will at the same time offer no
obstruction to the tightening up of the nut or bolt. In Figure 1 the
serrations are shown as confined to the outer portion only of the surfaces
of the washer, but they may be made to cover the entire surfaces as in
Figure 4.
Figure 4 shows a plan and Figure 6 shows a side view of a washer A
having small file-like serrations a formed on both surfaces, which serra-
tions may be either all radial as in Figure 1, or at a varying angle with the
radius or radii within certain limits, as shown, and Figures 8 and 9 show
respectively a plan and side view of a washer A, of a square form adapted
for fitting into a corresponding recess, such washer being also especially
applicable to wood or any soft or elastic material where a large bearing
surface is required. In this case the serrations a require to be formed only
on that side of the washer which is in contact with the nut or head of the
bolt.
Figure 6 shows a plan of a washer A having its surfaces set with rows
of jagged teeth a like those of a rasp instead of the serrations shown in
Figures 1, 4, and 8.
Figure 7 shows au example in which the serrations are made upon
the under sides of the nut and of the head of the bolt, whereby the
use of the washer shown in Figure 1 may be altogether dispensed with
while its advantages are retained, for in the operation of tightening
or screwing up the nut it will by the action of its own serrations be
prevented from becoming unscrewed, while at the same time the bolt
will be held stationary by the serrations upon its head indenting
themselves into the surface against which they bear, thus dispensing

page_text: with the necessity for making the bolt square under head or adopting
any other of the expedients now employed for preventing the turning of
This latter
the bolt during the operation of screwing up the nut.
advantage is equally gained by the use of a serrated washer placed
beneath the head of the bolt as well as beneath the nut as in Figure 10,
which shows the application of my Invention to an ordinary fished
joint of a rail. The serrations may in certain cases be formed both upon
the nut and bolt head and these used in combination with the serrated.
washers.
Having thus described the nature of my Invention and in what
manner the same is to be performed, I wish it to be understood that
I in no way limit myself to the precise arrangements thereof as shown
on the accompanying Sheet of Drawings, as the form of the washers
or of the serrations, projections, or indentations, as also the mode of
applying the same, may be variously modified without departing from
the nature of my Invention; but what I claim is, constructing the
washers, nuts, and heads of bolts, or any or all of these with serra-
tions, indentations, corrugations, or projections on their bearing surface
or surfaces, so formed that while they offer no obstruction to the
screwing up of the bolt or nut, they will, by indenting themselves into
the surface against which they bear, prevent the turning of the nut or
bolt head in the reverse direction, substantially as herein-before set
forth.
In witness whereof, I, the said Henry Chapman, have hereunto
set my hand and seal, this Twenty-ninth day of July, in the year
of our Lord One thousand eight hundred and sixty-eight.
HENRY CHAPMAN. (L.S.)