IMPROVEMENTS IN THE CONSTRUCTION OF SEWING MACHINES
Year: 1869

page_text: LETTERS PATENT to Theophilus Coad, of Truro, in the County of
Cornwall, Mathematical Instrument Maker, for the Invention of
"IMPROVEMENTS IN THE CONSTRUCTION OF SEWING MACHINES."
Sealed the 11th February 1870, and dated the 14th August 1869.
PROVISIONAL SPECIFICATION left by the said Theophilus Coad at the
Office of the Commissioners of Patents, with his Petition, on the
14th August 1869.
I, THEOPHILUS COAD, of Truro, in the County of Cornwall, Mathe-
matical Instrument Maker, do hereby declare the nature of the said.
Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF SEWING MACHINES," to
be as follows:-
This Invention relates, firstly, to certain means for opening out the
loop of the needle thread so as to allow of the use of a shuttle of suffi-
cient capacity to carry an ordinary reel of cotton or other thread, and

page_text: thus avoid the necessity which now exists of rewinding the thread,
cotton, or silk before inserting it in the shuttle.
Secondly. The Invention relates to an arrangement suitable for paying
out and taking up the slack of the needle thread when a large shuttle is
employed. The loop of the needle thread is caught by a looper of
peculiar construction, which then descends, and while drawing down
and elongating the loop also expands it laterally, thereby providing a
sufficient opening for the large shuttle to pass through. Allixed to and
pendent from the shuttle race is a V guide, in which works a short slide.
Pivotted to this slide is the looper, the upper end of which terminates in
a hook or finger for entering the loop of the needle thread. The lower
end of this looper is slotted, and in the slot plays a bent rock lever,
which is pivotted thereto at right angles to the pivot which connects the
looper with the slide. The upper end of the rock lever terminates in
a hook or finger corresponding to that of the looper. These hooks or
fingers lie side by side when the loop is to be entered, and they are held
in that position by means of a spring. The tail of this bent lever pro-
jects through a fixed plate attached to the V guide. This fixed plate has
a rectangular hole sufficiently large to allow of the rock lever moving
vertically and horizontally therein. As the looper moves away from the
needle the tail of the rock lever (which forms an incline) by bearing
against the lower end of the slotted plate will be tipped, and conse-
quently the hooked end of the bent lever will move away from the
looper and open out the loop laterally for the passage of the shuttle:
When the looper rises the hooked lever will be pressed inwards to the
proper position for entering another loop.
To facilitate the paying out and taking up of the slack thread the
needle thread, bobbin, and the friction discs or their equivalent are
mounted on a slide carried by the bracket arm of the machine. A
traverse motion is given to this slide, the advance of which provides the
slack requisite for the needle, and its return motion ensures the take up
of the extra slack, and gives the tension requisite for tightening the
stitch. The traverse of the slide and the rise and fall of the looper may
be effected by independent cams on the cam shaft.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Theophilus. Coad in the Great Seal Patent Office
on the 14th February 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THEOPHILUS
COAD, of Truro, in the County of Cornwall, Mathematical. Instrument
Maker, send greeting:
WHEREAS Her most Excellent Majesty Queen, Victoria, by Her
Letters Patent,. bearing date the Fourteenth day of August, 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 successors,
give and grant unto me, the said Theophilus Coad, Her special licence
that I, the said Theophilus Coad, my executors, administrators, and
assigns, or such others as I, the said Theophilus Coad, 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
THE CONSTRUCTION OF SEWING MACHINES," upon the condition (amongst
others) that I, the said Theophilus Coad, my executors or adminis-
trators, 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 inmediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said Theophilus Coad, do hereby declare
the nature of my 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 Drawing hereunto
annexed, and to the letters and figures marked thereon (that is to say):-
This Invention relates, firstly, to certain means for opening out the
loop of the needle thread, so as to allow of the use of a shuttle of
suflicient capacity to carry larger supply of thread than is now usual,

page_text: for example an ordinary reel of cotton or other thread, and thus to
avoid the necessity which now exists of frequently stopping the action
of the machine to renew the supply of thread to the shuttle or of
re-winding the thread, cotton, or silk before inserting it in the shuttle.
Secondly. The Invention relates to an arrangement suitable for giving
out and taking up the slack of the needle thread when a large shuttle
is employed. The loop of the needle thread is caught by a looper of
peculiar construction, which then descends and while drawing down
and elongating the loop also expands, it laterally, thereby providing a
sufficient opening for the large shuttle to pass through. The giving out
and taking up of the slack of the needle thread is effected by traversing
the bobbin and its accessories or the tension discs or their equivalent
only to and from the needle, the movements being timed to suit the
requirements of the needle and shuttle.
In the accompanying Drawing, Fig. 1 is a longitudinal sectional
elevation of a sewing machine fitted with my improvements; Fig. 2
is a transverse section shewing the relative position of the needle, the
shuttle, and the looper at the moment when the looper commences to
open the loop of the needle thread for the passage of the shuttle;
Fig. 3 is a partial sectional elevation of the machine taken at the
opposite side of the bracket arm to that represented at Fig. 1; Fig. 4
is a longitudinal section shewing the looper in action and the mechanism
for operating the looper; and Fig. 5 is a transverse section shewing
the looper in front view, and in position corresponding to that of
Fig. 4. In its general construction the machine is or may be assimilated
to sewing machines of the same class, and it requires therefore no
detailed description of its construction or mode of working, as these
points will be readily comprehended by any manufacturer of sewing
machines.
Affixed to and pendent from the shuttle race A is a V guide B, in
which works a short brass slide C. Pivotted to this slide is a compound
looper D, D', the upper end of which terminates in a hook or finger
for entering the loop of the needle thread. The lower end of the
part D of this looper is slotted, and in the slot plays the part D' of
the looper, which consists of a bent rock lever pivotted to the part D
at right angles to the pivot which connects the looper with the slide C.
The upper end of the rock lever D' terminates in a hook or finger

page_text: corresponding to that of the part D of the looper. These hooks or
fingers lie side by side as shewn at Fig. 1, when the loop of the needle
thread is to be entered, and they are held in that position by means
of a pressure spring D', which is fixed to the part D and bears upon
the part D as shewn at Fig. 2. The tail of this bent lever D' is tapered
on its inner face, and it projects through a rectangular opening in a
fixed plate B attached to the V guide B, and it. rides upon the bar
which closes this opening. The slot or opening in the plate is
rectangular and sufficiently large to allow of the rock lever D' moving
vertically and horizontally therein. As the slide C carrying the looper
moves away from the needle, the tail of the rock lever by bearing
against the lower end of the slot or opening in the plate B' will be
tipped, and consequently the hooked end of the bent lever D' will move
away from the part D of the looper and open out the loop laterally, as
shewn at Fig. 4, for the passage of the shuttle. After the passage of the
shuttle through the loop the looper will rise, and the hooked lever being
then free to return to its quiescent position will be pressed inwards and
returned to the proper position for entering another loop. The looper is
operated by a bell-crank lever E, to which it is connected by a ball-and-
socket joint. This lever rocks on a stud carried by a bracket pendent
from the bed of the machine, and it carries at its rear end a pin or
bowle which works in a groove cam F mounted on the cross driving
shaft G. The arrangement for facilitating the paying out and taking
up of the slack thread is shewn at Fig. 3, where H is the needle thread
bobbin, and I the friction discs or their equivalent; K is a slide carried
by the bracket arm of the machine, and attached to this slide are
the supports for the bobbin, and the friction discs or their equivalent,
or the bobbin may be stationary as usual. A traverse motion is given
to this slide K, and its advance provides the slack to the needle requisite
for opening out the loop by the looper, while its return motion ensures
the take up of the extra slack and gives the tension requisite for
tightening the stitch. The traverse of the slide K is effected by the
action of a grooved cam L (on the driving shaft G) upon a rock lever M
connected by an adjustable link coupling N to the slide, and working
on a stud carried by a bracket below the bed of the machine.

page_text: of carrying the same into effect, I wish it to be understood that under
the above in part recited Letters Patent I claim,—
First. The compound looper constructed and operating in the manner
above described.
Secondly. The traverse motion arrangement for giving out and taking
up the slack of the needle thread..
In witness whereof, I, the said Theophilus Coad, have hereunto.
set my hand and seal, the Twelfth day of February, in the year
of our Lord One thousand eight hundred and seventy..
THEOPHILUS. COAD. (L.S.)