AN IMPROVED NUT FOR SCREW BOLTS
Year: 1869

page_text: LETTERS PATENT to William Robert Lake, of the "International
Patent Office," Southampton Buildings, London, Consulting En-
gineer for the Invention of "AN IMPROVED NUT FOR SCREW BOLTS."-
A communication from abroad by Daniel Rice Pratt, of Worcester,
Massachusetts, United States of America.
Sealed the 14th April 1870, and dated the 18th October 1869.
PROVISIONAL SPECIFICATION left by the said William Robert
Lake at the Office of the Commissioners of Patents, with his
Petition, on the 18th October 1869.
I, WILLIAM ROBERT LAKE, of the "International Patent Office,"
Southampton Buildings, London, Consulting Engineer, do hereby declare
the nature of the said Invention for "AN IMPROVED NUT FOR SCREW BOLTS,"
a communication, to be as follows:-
This Invention relates to nuts which when placed upon their bolts
and properly tightened down upon a bearing surface will be through

page_text: the peculiar manner in which they are constructed and without the
aid of other nuts or separate pins, keys, or other fastenings securely re-
tained thereon unaffected by the motion or vibration of the parts to which
they are applied, or by other causes by which ordinary nuts are rendered
accidentally loose upon their bolts. The insecurity of such ordinary nuts
has given rise to many contrivances for locking or binding them upon their
bolts, but these contrivances have either been found partially or entirely
ineffectual, or on the other hand have been too costly for general use.
The object of this Invention is the production of a perfectly secure
nut which shall not be costly of manufacture or of unsightly appearance,
which shall require no peculiar adaptation to the bolt or to the surfaces
upon which it is to be placed, which will be simple and durable, and
which may be conveniently used for railway purposes, for machinery and
engine work, and for all purposes to which ordinary metallic nuts are
applied.
This object is accomplished by making the nut in two parts (one of
which has screw threads to fit the bolt, while the other forms the bearing
surface), and inserting between these two parts an elastic washer or
cushion, which when the nut is screwed down with its bearing surface
upon the object to be secured will cause the threads of the screwed
portion of the nut to bind. tightly upon the threads of the bolt, the
pressure being increased by tightening the nut upon its bearing surface,
but the nut having to be slackened to a considerable extent before it
ceases to be effectual. The said nut may be made round, square,
hexagonal, or of any other convenient form. The bottom part is pre-
ferably made in the form of a shallow socket to receive the spring or
elastic washer, and to fit over a portion of the upper or screwed part,
the two parts being so fitted together that though they will move
independently endwise, they cannot turn independently of each other.
It is obvious that an elastic or yielding pressure such as is thus pro-
duced upon the threads of the nut and bolt will effectually accomplish
the desired object, as it would be practically impossible for the nut to
be so far slackened by vibration or by the contraction of parts between
the bolt head and nut or by the expansion of the bolt to such an extent
as to free it from the spring or elastic cushion.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Robert Lake in the Great Seal Patent
Office on the 18th April 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
ROBERT LAKE, of the "International Patent Office," Southampton
Buildings, London, Consulting Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of October, in the
year of our Lord One thousand eight hundred and sixty-nine, in the
thirty-third year of Her reign, did for Herself, Her heirs and suc-
cessors, give and grant unto me, the said William Robert Lake, Her
special licence that I, the said William Robert Lake, my executors,
administrators, and assigns, or such others as I, the said William Robert
Lake, 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
"AN IMPROVED. NUT FOR SCREW BOLTS," a communication to me from abroad
by Danicl Rice Pratt, of Worcester, Massachusetts, United States of
America, upon the condition (amongst others) that I, the said William
Robert Lake, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should par-
ticularly 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 William Robert Lake, 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 accom-
panying Drawing forming a part of this Specification.
This Invention relates to nuts which when placed upon their bolts
and properly tightened down upon a suitable bearing surface will be byi
reason of their peculiar construction securely retained thereon without.

page_text: the aid of separate locking or fastening devices, such as split pins, keys,
pinching screws, or the like, and will be unaffected by the motion or
vibration of the parts or objects to which they are applied, or by other
influences which cause the loosening or slackening of ordinary nuts
upon their bolts. It is well known that the insecurity of such ordinary
nuts has frequently occasioned serious accidents with machinery and
upon the permanent way of railways and in other cases, and the
necessity of constant supervision, and of replacing those that are lost is
a continual source of expence and trouble. The necessity for obviating
these difficulties has given rise to various contrivances for locking or
securing screw nuts upon their bolts, but such contrivances have either
been found more or less ineffectual, or have been too costly for general
use.
The object of this Invention is the production of a perfectly secure
nut which shall not be costly of manufacture or unsightly in appearance.
which shall require no peculiar adaptation to the bolt or to the surface
of the piece or object whereon it is to be tightened, which will be simple
of construction and durable, and which may be conveniently used for
railways, for steam engines, and other machinery, and for all purposes to
which ordinary metallic nuts are applied.
This object is accomplished as follows:-The nut is made in two parts
one of which has screw threads to fit the bolt, while the other part forms
the tightening portion which bears upon the surface of the piece or
object to be secured. Between these two parts of the nut I insert an
elastic washer or cushion, which when the nut is screwed down or
tightened with its bearing surface properly in contact with the piece or
object to be secured or on which it is to rest will cause the threads of the
screw part of the nut to bind tightly upon the screw threads of the bolt,
the pressure being increased in proportion as the nut is tightened down
upon the bearing surface, but such pressure always acting between
certain limits which are determined by the extent of compression and
expansion of the washer, so that the nut may be unscrewed to any
distance within the aforesaid limits without being freed from the binding
pressure and becoming slack upon the bolt.
In order that the said Invention may be more fully understood, I have
illustrated the same in the accompanying Drawing, which I will now

page_text: Figure 1 is a top view of one of my improved nuts; Figure 2 is a
section of the said nut shewing the same upon the end of a bolt;
Figure 3 illustrates the manner of securing the nut by applying the
spring washer or elastic cushion to the head of the bolt. Like letters
indicate the same parts in each of the Figures.
a is the part of the nut which is provided with the screw threads, as
clearly shewn in Figure 2; 6 is the part which rests on the surface of the
fish-plate, bar, rail, plate, block, flange, or other piece or object to be
secured, or which is to have some piece or object secured thercon; c is
the elastic washer or cushion, which is preferably made of india-rubber,
but which may be of metal or other material possessing the required
clasticity.
It will be seen that I have shown the part 6 in the form of a shallow
cup or socket, in the bottom of which is placed the elastic washer c,
while the cylindrical portion of the said cup encloses the lower portion
of the screw part a.
The said part a has ears or lugs a', at each side
of which are formed notches or recesses to receive projections b' on the
interior surface of the cup b; by this means the two parts are so fitted
and held together that each will move independently of the other end-
wise or in the direction of the axis of the bolt d, but neither of them
can turn upon the bolt independently of the other. I do not however
confine myself to any particular form or shape of the parts a, b, of the
nut, as they may be made square, hexagonal, or of any other convenient
form without in any way departing from this Invention.
It is obvious that an clastic or yielding pressure such as is produced
upon the screw threads of the nut and bolt will effectually accomplish
the desired object, as it would be practically impossible that the nut
should be accidentally turned by vibration or otherwise so far in one
direction as to free the threads from the binding pressure exerted by
the clastic cushion c, or that there should such a contraction of the
parts between the head of the bolt and the nut, or such an expansion of
the bolt as would free the nut from such pressure.
Having thus fully described the said Invention as communicated to
me by my foreign correspondent, I wish it understood that I claim, au

page_text: clastic or spring nut, consisting of the two parts a and b and the elastic
cushion or washer e, substantially as and for the purpose set forth.
In witness whereof, I, the said William Robert Lake, have here-
unto set my hand and seal, this Eighteenth day of April, in the
year of our Lord One thousand eight hundred and seventy.
WILLIAM ROBERT LAKE. (L.S.)
Witness,
HARRY WRAIGHT,
Clerk to Messrs. Haseltine, Lake, & Co.,
Southampton Buildings,
London..