IMPROVEMENTS IN SEWING MACHINES
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by the said John MoDevitt at the
Office of the Commissioners of Patents on the 3rd October 1883.
JOHN MODEVITT of Belfast in the County of Antrim " IMPROVEMENTS IN
SEWING MACHINES,"
This Invention, which relates to improvements in Hem stitching sewing
machines has for its object to obviate the expense and trouble heretofore
experienced with such machines when changing them from one class of work to
another, the said machines as ordinarily constructed at such times making or
being liable to make thick stitches and leave threads, and the Invention has
further for its object to enable the person using the machine to adapt it to
different kinds of work without calling in the assistance of a mechanic to alter
the working of the machine as at present.
These objects are effected by the employment of a cam in addition, and affixed
to the ordinary stitch cam. The additional cam has a second screw in conjunction
with it and working independently and by adjusting the said screw the worker
is personally enabled to change and adapt the machine from one class of work to
another at pleasure.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John MoDevitt in the Patent Office on the 1st April 1884.
JOHN MCDEVITT of Belfast in the County of Antrim,
SEWING MACHINES
IMPROVEMENTS IN
My said Invention which relates to improvements in Hem-stitch sewing
machines has for its object to obviate the trouble and expense hitherto generally
experienced with such machines when changing them from one class of work to
another and also to obviate the liability of the said machines as ordinarily
constructed to make "thick" stitches and leave threads at such times and my said
Die A71

page_text: Invention has further for its object to enable the person using the machine to
adapt it to different kinds of work without calling in the aid of a mechanic to
alter the working parts as heretofore.
These objects are effected by the employment of a cam in addition to and
affixed to or formed on the ordinary stitch cam the additional cam having a
second screw in conjunction with it and working independently of the ordinary
screw.
By adjusting the said additional screw the worker is personally enabled to
change and adapt the machine from one class of work to another at pleasure.
And in order that my said Invention may be properly understood I have
hereunto appended an explanatory sheet of drawings illustrative of the system,
mode, or manner in or under which it is or may be used or carried out in
practice.
Figure 1, of the drawings is a front elevation and figure 2, a side elevation of
the ordinary stitch wheel A, rocking shaft B, and feed lever C, whilst figure 3, is
a detailed side elevation and figure 4, a detailed plan of the said stitch wheel. On
these figures D, D, represent the ordinary cams by which through the intervention
of the screw E, and lever F, rocking motion is communicated to the shaft B, and
lever C, by which the feed is actuated. The additional cam is marked G, and as
seen by the drawings it is also formed on or fixed to the side of the stitch wheel A,
and acts on a screw H, carried in the lower end of a lever I, whose upper end is
secured to the rocking shaft B.
By this arrangement it will be seen that the motion of the rocking shaft and
of the feed lever C, and consequently the class of stitch may be altered at pleasure
by the worker of the machine simply turning the screw E, back, so as to prevent
the cams D, from acting on it and turning the screw H, until its point is in
position to rock the shaft B, by the action on the screw of the cam G, as the
stitch wheel A, rotates.
Having now described and particularly ascertained the nature of my said
Invention and the system, mode, or manner in or under which it is or may be
used or carried out in practice 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 combination of the cam G, with the ordinary cams D, on the stitch
wheel of hem-stitch sewing machines substantially as herein before described with
reference to the appended drawings.
Second-The combination of the cam G, screw H, and lever I, with the ordinary
stitch cam wheel and apparatus in conjunction with it for communicating motion
to the feed in hem-stitch machines substantially as and for the purposes
herein before described with reference to the drawings hereunto annexed.
In Witness Whereof, I, the said John M'Devitt, have hereunto set my hand
and seal, this twenty ninth day of March in the year of our Lord, One thousand
eight hundred and eighty four.
Innתמ160 TAN
nזמ10
JOHN MODE
5.)
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