IMPROVEMENTS IN in, for the Invention of SEWING MACHINES
Year: 1874

page_text: LETTERS PATENT to William Frederick Thomas, of No. 1, Cheapside,
"IMPROVEMENTS IN
in the City of London, for the Invention of
SEWING MACHINES."
Sealed the 20th November 1874, and dated the 24th September 1874.
PROVISIONAL SPECIFICATION left by the said William Frederick
Thomas at the Office of the Commissioners of Patents, with his
Petition, on the 24th September 1874.
I, WILLIAM FREDERICK THOMAS, of No. 1, Cheapside, in the City of
London, do hereby declare the nature of the said Invention for "Iм-
PROVEMENTS IN SEWING MACHINES," to be as follows:-
This Invention relates to improvements in lock stitch sewing machines,
particularly such as are applied to the stitching of leather or other pur-
poses for which waxed threads are employed.
I provide a tubular shuttle bent to a circular curvature with a pointed
end for entering the loop of the needle thread, and into this shuttle I

page_text: insert the under thread as a cop, which bends to the curvature of the
shuttle. I place the shuttle in a circular race formed under the table of
the machine in such a position that the needle descends in a chase at the
side of the race. A spindle mounted in the centre of the race, and
having on it an arm for driving the shuttle, receives a reciprocating
rotary motion from a cam, such motion being properly timed so that
the shuttle is caused to enter the loop of the needle thread, the formation
of which loop may be facilitated by a finger worked by a cam so as to
bulge the thread off the needle before the entry of the shuttle. During
the passage of the shuttle through the loop, the latter has to slip only
along the inner periphery of the shuttle; which is short and presents a
curvature that renders the slip casy. As the shuttle rotates its thread is
carried across the central part of the race, and in order to provide the
necessary tension I cause the shuttle thread to be pressed against the
cover of the race by a lever acted on by an adjustable spring, the pressure
of the spring being relieved when required by the action of a cam.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Frederick Thomas in the Great Scal
Patent, Office on the 24th March 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAMS
FREDERICK THOMAS, of No. 1, Cheapside, in the City of London, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fourth day of September, in the
year of our Lord One thousand eight hundred and seventy-four, in
the thirty-eighth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said William Frederick Thomas,
Her special license, that I, the said William Frederick Thomas, my
executors, administrators, and assigns, or such others as I, the said
William Frederick Thomas, my executors, administrators, and assigns, a
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
-
J

page_text: Isle of Man, an Invention for "IMPROVEMENTS IN SEWING MACHINES," upon
the condition (amongst others) that I, the said William Frederick
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 William Frederick Thomas, do
hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascer-
tained 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 relates to improvements in lock stitch sewing machines,
particularly such as are applied to the stitching of leather or other pur-
poses for which waxed threads are employed.
I provide a tubular shuttle bent to a circular curvature with a pointed
end for entering the loop of the needle thread, and into this shuttle I
insert the under thread as a cop, which bends to the curvature of the
shuttle. I place the shuttle in a circular race formed under the table
of the machine in such a position that the needle descends in a chase at
the side of the race. . A spindle mounted in the centre of the race,
and
having on it an arm for driving the shuttle, receives a reciprocating
rotary motion from a cam, such motion being properly timed so that the
shuttle is caused to enter the loop of the needle thread. During the
passage of the shuttle through the loop, the latter has to slip only along
the inner periphery of the shuttle, which is short and presents a curva-
ture that renders the slip casy. As the shuttle rotates its thread is
carried across the central part of the race, and in order to provide the
necessary tension I cause the shuttle thread to be pressed against the
cover of the race by a lever, acted on by an adjustable spring, the pressure
of the spring being relieved when required by the action-of a cam.
An
TY

page_text: Fig. 3 is a plan of the lower arm on which the material to be sewn is
placed.
Figs. 4, 5, 6, and 7 represent respectively a plan, a side view, a trans-
verse section, and a perspective view of the shuttle.
The movements of the needle and feed are effected by cams in the
ordinary way. A cam A on the main shaft of the machine works a
sliding bar B, on which is a toothed rack 6 gearing with a pinion C, the
axis c of which projects upwards into the middle of the circular shuttle
race, and has on it a shuttle driver c¹, so that at each revolution of the
main shaft the shuttle driver is caused to make a partial rotation, about
three-quarters of a whole revolution forwards and backwards. The
shuttle D is of the form shewn in section at Fig. 6 with a flat side
towards the needle and the opposite side rounded. A portion of the
flat side dis hinged so as to form a lid, which is shown opened
out in Fig. 4 for the purpose of placing within the shuttle the cop of
underthread E, which is readily bent to lie in the curved shuttle. The
end of the thread taken from the interior of the cop is passed down
through a hole and then up again so as to issue from the upper side of
shuttle at e. The spindle of the shuttle driver is bored up, and a
small spindle F carrying a button at top is fitted to work vertically
therein without revolving. The lower end of this spindle is screwed
into a square nut, and secured therein by a lock nut, and this square-
nut is held in the fork of a lever G, the end of which rests on the edge
of a cam H. A spring K, adjustable by screws, presses down the one
end of the lever G, thereby forcing the button of the spindle F up to
the cover of the shuttle race whenever the hollow of the cam H
presents itself to the end of the lever G. The needle thread may be
taken from a reel in the ordinary way, having been previously waxed, or
it may be waxed as it is used by passing it through a pot L containing
wax, which pot is placed in a jacket containing oil heated by a gas
flame M. As the thread on its way from the pot L to the needle is
cooled, I prefer to pass it through a tube N close to the needle, against
which tube, as it oscillates upwards and downwards with the needle, a
small gas jet n plays.
1
Although I have shewn in the Drawings the shuttle working in its
circular race horizontally on the inner side of the needle, it is obvious
that it might be arranged to work on the other side of the needle and
also in a vertical instead of a horizontal plane.

page_text: Having thus described the nature of my Invention, and in what
manner the same is to be performed, I claim,-
First. The use in wax thread sewing machines of a curved shuttle
adapted to work in a circular race, and to receive a cop bent to its
curved form, substantially as herein described.
Second. The use in combination with a shuttle, such as is referred to
above, of a lever operating in combination with a sliding spindle and
button for the purpose of giving tension to the shuttle thread after it
has left the shuttle, substantially as herein described.
In witness whereof, I, the said William Frederick Thomas, have
hereunto set my hand and scal, this Twenty-second day of March,
in the year of our Lord One thousand eight hundred and seventy-
five.