IMPROVEMENTS IN SCREW BOLTS AND NUTS FOR SECURING FISH PLATES AND OTHER OBJECTS
Year: 1868

page_text: LETTERS PATENT to Charles Denton Abel, of No. 20, Southampton
Buildings, Chancery Lane, in the County of Middlesex, Patent
Agent, for the Invention of "IMPROVEMENTS IN SCREW BOLTS AND NUTS
FOR SECURING FISH PLATES AND OTHER OBJECTS."-A communication
from abroad by Frederic Tudor, of Boston, in the State of Massa-
chusetts, United States of America.
Sealed the 28th April 1868, and dated the 9th March 1868.
PROVISIONAL SPECIFICATION left by the said Charles Denton Abel
at the Office of the Commissioners of Patents, with his Petition, on
the 9th March 1868.
I, CHARLES DENTON ABEL, of No. 20, Southampton Buildings,
Chancery Lane, in the County of Middlesex, Patent Agent, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN SCREW
BOLTS AND NUTS FOR SECURING FISH PLATES AND OTHER OBJECTS," to be as
follows:-
This Invention consists in constructing screw bolts with two threads
of a different pitch, and with square or polygonal ends of less dimensions
than the other part whereby to turn the bolt.
These bolts are provided

page_text: with two nuts, one at each end, each nut having a thread of a pitch
corresponding to the thread of that part of the bolt on which it fits.
These nuts are so formed that they cannot turn, for which purpose
they are by preference made either hemispherical with a square or
polygonal projection on the flat face, fitting into a corresponding recess
in the surface of the object to be secured; or they are made semi-
cylindrical, with the curved part fitting in a correspondingly curved
recess in the surface of the said object. In some cases nuts may be
dispensed with and threads be cut in the fish plates or other objects
to be secured. It will be seen that by this arrangement if the screw
bolt is first passed through the holes in the fish plates and rail or
other object, and a nut is then screwed on to each end, and the bolt
is then turned round in the nuts by a spanner that part of the bolt
with a thread of a quicker pitch than the other part will advance
more rapidly through its nut than the other part will pass through the
other nut, and consequently the two nuts will be caused to approach
each other on the bolt and be made to clip the fish plates or other
objects situated between them with great force.
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said Charles Denton Abel in the Great Seal Patent 2
Office on the 25th August 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
DENTON ABEL, of No. 20, Southampton Buildings, Chancery Lane, in
the County of Middlesex, Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her 2
Letters Patent, bearing date the Ninth day of March, 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 Charles Denton Abel, Her special
licence that I, the said Charles Denton Abel, my executors, adminis-
trators, and assigns, or such others as I, the said Charles Denton Abel,
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,

page_text: exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN SCREW BOLTS AND NUTS FOR SECURING FISH PLATES AND
OTHER OBJECTS," a commmunication to me from abroad by Frederic
Tudor, of Boston, in the State of Massachusetts, United States of
America, upon the condition (amongst others) that I, the said Charles
Denton Abel, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, 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 Charles Denton Abel, 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 :-
This Invention consists in constructing screw bolts with two threads
of a different pitch and with square or polygonal ends of less
dimensions than the other part, whereby to turn the bolt. These
bolts are provided with two nuts, one at each end, each nut having
a thread of a pitch corresponding to the thread of that part of the
bolt on which it fits. These nuts are so formed that they cannot
turn, for which purpose they are by preference made either hemi-
spherical with a square or polygonal projection on the flat face,
fitting into a corresponding recess in the surface of the object to be
secured; or they are made semi-cylindrical, with the curved part
fitting in a correspondingly curved recess in the surface of the said
object. It will be seen that by this arrangement if the screw bolt
is first passed through the holes in the fish plates and rail or other
object, and a nut is then screwed on to each end and the bolt is then
turned round in the nuts by a spanner, that part of the bolt with a
thread of a quicker pitch than the other part will advance more
rapidly through its nut than the other part will pass through the
other nut, and consequently the two nuts will be caused to approach
each other on the bolt and be made to clip the fish plates or other
objects situated between them with great force.

page_text: On the accompanying Sheet of Drawings are shown some of the
arrangements by which this Invention may be carried into effect.
Figure 1 shows the application thereof to the fish plates of double
headed rails.
Figures 2 and 3 show an arrangement in which the nuts are of
a semi-cylindrical form, and in which the Invention is applied to the
fish plates of flanged rails.
Figure 4 shows another modification in which the nuts have holes
drilled in them for the reception of pins which are made to enter
the fish plates, and thus prevent the nuts from turning.
Figures 5 and 6 show an enlarged plan and end view of the screw
bolt A with two threads a and a¹ running in the same direction, but
of different pitches, so that on turning the bolt one revolution in the
direction for, screwing up while the nuts B, B¹ are prevented from
turning with it, the nut B will be caused to travel a distance equal
to the pitch of the thread a towards the left hand, while the nut B¹
will at the same time travel the somewhat greater distance represented
by the pitch of the thread a', in the same direction, and consequently
there will result an effective tightening up of the two nuts equal to
the difference of the pitches of a and a¹. For preventing the nuts B
from turning they are either made to fit in a flat groove in the fish
plates C as at Figure 1, or they are made with a partly cylindrical
surface fitting into a corresponding concave groove in the fish plates
as at Figures 2 and 3, or they are secured by pins 6 as shown at
Figure 4. In this case the nuts B, B³, may be first screwed upon
the bolt A by means of a spanner until they come in contact with
the fish plates, and after then being fixed by means of the pins b, b¹,
the bolt A is turned by means of the square head for tightening up
as before described. The nuts being prevented from turning there
is no danger of the screw bolt becoming unscrewed by the jarring of
the rails as is the case with ordinary screw bolts.
Although I have described this Invention as applied to fish plates
only, yet I in no way limit myself to this application, as the
Invention may be employed with equal advantage in all cases where
screw bolts are used.
Having thus described the nature of this Invention, and the manner
of performing the same as communicated to me by my foreign

page_text: correspondent, what I claim is, the construction and use of screw
bolts with differential threads in combination with screw nuts,
operating substantially in manner and for the purposes herein-before
set forth.
In witness whereof, I, the said Charles Denton Abel, have hereunto
set my hand and seal, this Twenty-fifth day of August, in the
year of our Lord One thousand eight hundred and sixty-eight.
CHA. D. ABEL. (L.8.)