IMPROVEMENTS IN SEWING MACHINES
Year: 1862

page_text: LETTERS PATENT to Thomas Coltman, of Leicester, Machinist,. for the
Invention of "IMPROVEMENTS IN SEWING MACHINES."
Sealed the 3rd June 1862, and dated the 12th February. 1862.
PROVISIONAL SPECIFICATION left by the said Thomas Coltman, at the
Office of the Commissioners of Patents, with his Petition, on the-
12th February 1862.
I, THOMAS COLTMAN, of Leicester, Machinist, do hereby declare the nature.
of the said Invention for "IMPROVEMENTS IN SEWING MACHINES," to be as
follows:-
My Invention of improvements in sewing machines has for its object. to
produce a fast or secure stitch, which is not liable to be drawn out, and
which is also an elastic stitch which cannot be broken by pulling or stretching:
the cloth. This is effected by the use of two needles, one placed above and.
the other below the cloth. These needles are mounted in guides at an angle.
to each other, and by means of cranks or excentrics are made to move up and.
down and pass their points through the cloth alternately, and in so doing the
upper needle, for instance, when drawn. back will leave a loop, through which.

page_text: the lower needle will pass. This latter in returning also leaves a loop, through
which the upper needle in its turn will pass, and so on, each needle alter-
nately passing through the loop formed by the other. The cloth or work is
moved forward by means of toothed rings or roughened annular surfaces,
which are actuated either by pinions or by friction of contact of elastic surface
rollers. The needles are arranged to work between these toothed rings or
roughened annular surfaces, which therefore will bear on each side of the
seam and keep the work straight and steady.
SPECIFICATION. in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Coltman in the Great Seal Patent Office on the
12th August 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
COLTMAN, of Leicester, Machinist, send greeting:..
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twelfth day of February, in the year, of our Lord
One thousand eight hundred and sixty-two, in the twenty-fifth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Thomas Coltman, Her special license that I, the, said Thomas
Coltman, my executors, administrators, and assigns, or such others as I, the
said Thomas Coltman, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times there-
after 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 "IMPROVE-
MENTS IN SEWING MACHINES," upon the condition (amongst others) that I, the
said Thomas Coltman, by an instrument in writing under my hand and seal,
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 Thomas Coltman, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed; to be particularly described and ascertained 'in and by the following

page_text: statement, reference being had to the Drawing hereunto annexed, and to the
letters and figures marked thereon (that is to say):-
My Invention of "Improvements in Sewing Machines" has for its object
to produce a fast or secure stitch, which is not liable to be drawn out, and:
which is also an elastic stitch which cannot be broken by pulling or stretching.
the cloth or work. This is effected by the use of two needles, one placed
above and the other below the cloth. These needles are mounted in guides.
at an angle to each other, and by means of cranks or excentrics are made to
move up and down, and pass their points through the cloth alternately, and in
so doing the upper needle, for instance, when drawn back will leave a loop,
through which the lower needle will pass before entering the cloth. This
latter in returning also leaves a loop, through which the upper needle in its
turn will pass before entering the cloth, and so on, each needle alternately
passing through the loop formed by the other. The cloth or work is moved
forward by means of toothed rings or roughened annular surfaces, which are
actuated either by pinions or by friction of contact of elastic surface rollers.
The needles are arranged to work between these toothed rings or roughened
annular surfaces, which therefore will bear on each side of the seam, and keep
the work straight and steady.
In the accompanying Drawing, Fig. 1 is a side view of a sewing machine,
constructed according to my Invention; Fig. 2 is a front view of the same;
Fig. 3 is an elevation of the rear end of the machine; Fig. 4 is a longitu-
dinal vertical section of the lower part, shewing the feed motion, and one of
the needle carriers; and Fig. 5 is a transverse vertical section, taken in the
line 1, 2, of Fig. 4.
a, a, is the driving shaft, on which is keyed the driving pulley b. At the
outer extremity of the shaft a is the crank c, which is coupled by means of a
double connecting rod d to the two cranks e and f, secured to the ends of the
two shafts g and h. The upper shaft 9 actuates the upper needle bar, and
the lower one h actuates the lower needle bar and feeding rings, hereafter
described. Each needle is supplied with thread from a separate bobbin i¹
and i. In the Drawing the threads of these two bobbins as shewn of dif-;
ferent colors, so that upon referring to the peculiar stitch produced by the
machine, as shewn in Fig. 6, and hereafter described, the interlacing of the
two threads may be clearly seen. It will be seen, on reference to Fig. 2, that;
the reciprocating needle bars i and * are so placed as to work up and down,
in guides j and * at an angle to the bed of the machine and to each other, and

page_text: they are actuated in the following manner:At the foremost end of the
shafts g and 'h are secured plates or discs k (see Figs. 2 and 4) provided with
annular grooves, which are cut excentrically to: the axis of their respective
shafts. Pins or studs projecting from the under side of the needle bars i
and take into these annular grooves, so that on the rotation of the shafts g
and the needle bars with their respective needles will be moved up and
down, as will be readily understood, and the two needles will alternately pass
a loop of thread through the cloth or other material to be sewn, and also
through the loop previously formed by the other needles, that is to say, the
upper needle, for instance, will descend through the cloth and form a loop on
the under side of the cloth; the lower needle will then pass up through this
loop and also through the cloth, and form a loop. on the upper side, through
which the upper needle, which will have been drawn out of the cloth, will pass
on its second descent, and so on, each needle passing in turn through the loop
formed by the other and forming a firm and elastic stitch, such as that shewn
Guides l,,
in the Diagram, Fig. 6, which is drawn on an enlarged scale.
are provided for the purpose of keeping the needles, steady in their proper
place, and ensuring their passing each other properly. In order to feed forward
the cloth or other material to be seen the following arrangement is employed:-
Two toothed or roughened annular rings m and m*, seen best in Figs. 1
and 4, are made to work smoothly round on the fixed segmental projecting
piece n, which is cast on the front of the main framing of the machine. On
the foremost end of the lower shaft h, and at the back of the disc k is placed
a sort of double screw cam, worm, or projecting feather o (see Fig. 4); the
projecting feather or thread of this cam or worm takes into a worm wheel p,
on the shaft of which is mounted a worm q, which gears into teeth cut on the
back of the annular ring m* (see Fig. 5). It will now be understood that
when the shaft h is rotated, an intermittent forward motion will be imparted to
the ring m* through the worm wheel p and worm q. This motion is com-
municated to the other ring m by means of a roller r covered with caoutchouc
or other suitable material, and placed so as to press upon the roughened
surfaces of both rings. In order to alter the length of the stitch, the worm q
must be changed for another worm of different pitch, according to the par-
ticular length of stitch required. This of course will alter the motion of the
feeding rings m, m*, and will modify the length of stitch accordingly. The
cloth or other material is kept down upon the rings by means of the presser
It will be obvious that the feeding rings m and m*
may be operated
foot s.

page_text: in other ways, as, for instance, by means of friction rollers or toothed wheels
placed so as to work against the inner periphery of the rings, but I prefer the
mode shewn in the Drawing. I would also observe that I sometimes find it
convenient to use only one of the serrated or roughened surface feeding rings m,
which may be actuated in the manner shewn and described.
I would remark that while the sewing operation is proceeding one or other
of the needles will always be in the cloth or fabric, even while the latter is
being fed forward; these needles must therefore be made so elastic that they
may without risk of derangement be bent out of a straight line by the onward
motion of the work, but immediately they are drawn out of the fabric they
will spring back into their normal position ready to make a new stitch in a
fresh place. Figs. 7 and 8 in the Drawings are side and edge views of one of
the needles, which being made flat, as shewn, possesses a considerable amount
of elasticity. The combined movements of the needles and feed motion are
as follows:-The top needle having been passed through the cloth, and having
commenced to return, the feed motion for carrying forward the cloth com-,
mences and moves the work forward, and in so doing springs or bends the
needle on one side. At the same time the needle by being drawn back opens
the loop and allows the bottom needle to enter such loop, and pass in its turn
through the cloth or work in a fresh place. The feed motion then carries the
cloth onward a second time, while the bottom needle is inserted therein, and
while withdrawing the needle a second loop is formed, through which the top
needle is passed, and so on, each needle alternately remaining in the cloth
while the latter is fed forward. When it is required to removed the work from
the machine both needles must of course be drawn out of the cloth. This is
effected by mounting the bottom crank f loosely on its shaft g, so that the
crank may be turned back one half of a revolution without moving the shaft.
It will be evident therefore that when the bottom needle is out of the work
the cranks e and f may be turned back, so as to raise the upper needle out of
the work also. The tablet of the machine upon which the work to be sewn
is placed is made moveable, so that it may be slidden back in order that the
needles may be got at with facility for threading or adjustment. In order to
remove the table t, the piece t' (which slides in a dovetail groove) must
be drawn out, and the set screw u unscrewed. The table t may then be slidden
back upon the rods v, v, and access may then be obtained to the needles. If it
be found necessary to remove the table t altogether the rods v may be
unscrewed and drawn out, and the table may then be lifted off.

page_text: Having now described my Invention of "Improvements in Sewing Machines,"
and having explained the manner of carrying the same into effect, I claim as
the Invention secured to me by the herein-before in part recited Letters
Patent, the mode herein set forth of arranging, combining, and working the
needles, so as to produce the elastic lock stitch shewn and described; I also
claim the mode herein set forth of feeding forward the work, and the arrange-
ment of parts for working the feed motion.
In witness whereof, I, the said Thomas Coltman, have hereunto set
my hand and seal, this Fourth day of August, in the year of our Lord
One thousand eight hundred and sixty-two.
Witness,
LEONARD ALFRED CLARKE,
Of Leicester,
(King St. Mills.)
THOMAS COLTMAN. (L.S.)