IMPROVEMENTS IN SEWING MACHINES
Year: 1873

page_text: LETTERS PATENT to John Hamilton, of Dromore, County Down,
Ireland, Engineer, for the Invention of "IMPROVEMENTS IN SEWING
MACHINES."
Sealed the 2nd September 1873, and dated the 26th March 1873.
PROVISIONAL SPECIFICATION left by the said John Hamilton at the
Office of the Commissioners of Patents, with his Petition, on the
26th March 1873.
I, JOHN HAMILTON, of Dromore, County Down, Ireland, Engineer,
do hereby declare the nature of my said Invention for "IMPROVEMENTS IN
SEWING MACHINES," to be as follows :—
"
This Invention relates to sewing machines intended for the production
of what is known as "French vein or open hem stitch, and consists
of improvements on the arrangements described in the Specification of
my Patent bearing date the 15th of February 1872, Number 474.
According to my present Invention I dispense with the gearing for
giving the three motions of the needle and shuttle to one revolution of
the feed cam, and I substitute therefor a pair of three-throw cams for

page_text: working the needle and shuttle respectively, whereby I am enabled to
mount the feed cam on the spindle common to the needle and shuttle
cams in lieu of mounting it on a separate shaft.
The operations of the needle, shuttle, and feeder, and the construction
of the shuttle and shuttle race are the same as described in my said
former Specification, but the feed cam is provided with an additional
swell in order to cause the cloth at each new stitch taken in the "shires "
to make a slight forward and backward movement during the time the
needle is in the shires, the effect of which is to separate or open out the
shires and thus to leave a freer and larger opening for the entrance of the
needle when making the back stitch. This arrangement effectually
prevents the appearance of the work, and dispenses with the subsequent
operation of examining or hand finishing.
The needle slide works in a guide which slides to and fro along the
neck or overhanging fixed arm of the machine for the purpose of im-
parting the requisite lateral motion to the needle to cause it to enter the
hem and the shires respectively at the proper periods, the said sliding
guide working in a dovetailed or other groove in the side of the neck of
the machine, and being actuated from a cam surface on the periphery of
the shuttle cam, adjustable screws being employed in conjunction with a
spring for regulating the extent of the lateral sliding movement of the
said needle slide guide. By this mode of imparting the lateral motion
to the needle a more certain, direct, and steady action is obtained, and
consequently the wear and tear of the machine is greatly reduced.
.
SPECIFICATION in pursuance of the conditions of the Letters Patent, 2
filed by the said John Hamilton in the Great Seal Patent Office
on the 25th September 1873.
:
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HAMILTON, of Dromore, County Down, Ireland, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-sixth day of March, in the
year of our Lord One thousand eight hundred and seventy-three, in
3

page_text: the 36th year of Her reign, did, for Herself, Her heirs and succes-
sors, give and grant unto me, the said John Hamilton, Her special
license that I, the said John Hamilton, my executors, administrators,
and assigns, or such others as I, the said John Hamilton, my
executors, administrators, or 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
SEWING MACHINES," upon the condition (amongst others) that I, the said
John Hamilton, my executors or administrators, by an instrument in
writing under my hand and seal, should particularly describe and ascer-
tain 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 John Hamilton, 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 accompanying
Drawings and to the letters and figures marked thereon, that is to
say:-
My said Invention relates to sewing machines intended for the pro-
duction of what is known as "French vein
or open hem stitch, and
consists of improvements on the arrangements described in the Specifi-
cation of my Patent bearing date the Fifteenth of February, Ono
thousand eight hundred and seventy-two, No. 474.
According to my present Invention I dispense with the gearing for
giving the three motions of the needle and shuttle to one revolution of
the first cam, and I substitute therefor a pair of three-throw cams for
working the needle and shuttle respectively, whereby I am enabled to
mount the first cam on the spindle common to the needle and shuttle
cams in lieu of mounting it on a separate shaft.
.The operations of the needle, shuttle, and feeder, and the construction
of the shuttle and shuttle race are the same as described in my said
former Specification, but the feed cam is provided with an additional
swell in order to cause the cloth at each new stitch taken in the shires.

page_text: to make a slight forward and backward movement during the time the
needle is in the shires, the effect of which is to separate or open out the
shires, and thus to leave a freer.and larger opening for the entrance of
the needle when making the back stitch. This arrangement effectually
prevents the needle from missing threads, improves the appearance of
the work, and dispenses with the subsequent operation of examining or
hand finishing.
The needle slide works in a guide which slides to and fro laterally
along the neck or overhanging fixed arm of the machine for the purpose
of imparting the requisite lateral motion to the needle to cause it to
enter the hem and the shires respectively at the proper periods, the said
sliding guide working in a dovetailed or other groove in the side of the
neck of the machine, and being actuated from a cam surface on the
periphery of the shuttle cam, adjustable screws being employed in con-
junction with a spring for regulating the extent of the lateral sliding
movement of the said needle slide guide. By this mode of imparting
the lateral motion to the needle a more certain, direct, and steady action
is obtained, and consequently the wear and tear of the machine is
greatly reduced.
And in order that my said Invention may be fully understood I shall
now proceed more particularly to describe the same, and for that purpose
shall refer to the several Figures on the annexed Sheets of Drawings,
the same letters of reference indicating corresponding parts in all the
Figures.
Figure 1 of my Drawings represents a full sized side elevation of the
improved sewing machine. Figure 2 is a back elevation of the same.
Figure 3 is an edge view of the feed cam, shewing the additional swell
thereon for imparting the forward and backward motion to the fabric
when the needle is in the shires. Figure 4 (Sheet 2) is a full sized fan
view of the needle cam showing the three-throw cam groove therein;
and Figure 5 is a similar view of the three-throw shuttle cam, the two
cams being drawn in the exact relative positions they would occupy
when mounted on the driving shaft.
A is the driving shaft of the machine driven by a pulley or otherwise.
Upon this shaft there are mounted the needle cam B, the shuttle cam C,
and the feed cam D, there being but one shaft in this machine. E is
the needle lever, carrying an antifriction pulley a, which works in the

page_text: three-throw cam groove 6 of the needle cam (shown clearly in Figure 4),
so that for each revolution of the driving shaft the needle will make
three double strokes. The rod F of the shuttle driver carries an anti-
friction pulley & which works in the three-throw cam grooves c of the
shuttle cam C (shown clearly in Figure 5), so that the shuttle is also
caused to traverse to and fro three times in concert with the needle for
each revolution of the driving shaft. The feed cam D (shewn in Figure 2
and in detail edgo view at Figure 3), which as before stated is mounted
on the same shaft as the needle and shuttle cams is provided with an
additional small lateral swell e, which acts against the end of the regu-
lating screw f in the feed lever G for the purpose of imparting a slight
forward and backward motion to the cloth during the time the needle is
in the shires with a view to the opening of the same more effectually
and the ensuring of the needle at its next descent entering between the
opened shires without catching a-shire as is now frequently the case. His
the needle slide which works vertically between two dovetailed guides g,.
(one of which is shewn as removed), secured to the slide I. This slide
works to and fro laterally between dovetailed guides h on the neck K of
the machine.. .It is bent downwards at a right angle at I' and carries an
antifriction roller i, which is operated upon by the enlarged part k, k³, k¹,
of the periphery of the shuttle cam, as shown more clearly in Figure 5.
An adjusting screw 1 serves to adjust the position of the antifriction
roller i towards or from the periphery of the cam C so as to regulate the
forward movement of the slide I, its backward movement obtained from
the helical spring m being regulated by the second adjusting screw
which strikes against a fixed stop n. By this means the requisite lateral
motion is imparted to the needle to cause it to enter the hem and the
shires respectively at the proper periods.
Having now described and particularly ascertained the nature of my
said Invention and the manner in which the same is or may be used or
carried into effect, I would observe in conclusion that what I consider
to be novel and original and therefore claim as the Invention secured to
me by the herein-before in part recited Letters Patent is,---
First. The application and use of three-throw cams for working the
needle and shuttle in machines of the class set forth, substantially as
herein-before described and illustrated by the Drawings annexed.
Second. Mounting the three-throw needle and shuttle cams as well

page_text: as the feed cam upon one and the same driving shaft, as herein-before
described and illustrated by the Drawings annexed.
Third. The imparting a slight forward and backward movement to the
cloth during the time the needle is in the shires, substantially in the
manner and for the purpose herein-before described.
Fourth. The peculiar arrangement of slido and parts connected there-
with for imparting the requisite lateral moevment to the needle in
machines of the class set forth, as and for the purpose herein-before
described and illustrated by the Drawings annexed.
In witness whereof, I, the said John Hamilton, have to this my
Specification set my hand and seal, the Twenty-fourth day of
September, One thousand eight hundred and seventy-three.
JOHN HAMILTON. (L.S.)