IMPROVEMENTS IN AND RELATING TO OVER- EDGE STITCH SEWING MACHINES, CHIEFLY DESIGNED FOR THE MANUFACTURE OF SACKS AND SIMILAR ARTICLES."
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by William Webster at the Office of the
Commissioners of Patents on the 17th March 1877.
"
WILLIAM WEBSTER, of San Francisco, State of California, United States of
America, now of Dundee, Scotland. IMPROVEMENTS IN AND RELATING TO OVER-
EDGE STITCH SEWING MACHINES, CHIEFLY DESIGNED FOR THE MANUFACTURE OF
SACKS AND SIMILAR ARTICLES."
My Invention relates to sewing machines which have a spiral needle and sew
with twine or similar material, and make what is called the overedge stitch, and
which are chiefly designed for sewing sacks, bags, and other coarse and heavy
work.
The said Invention comprises an arrangement of spools or rollers which form a
twine carrier and controller, and prevent friction and strain on the twine between
the eye of the needle and the stitching. These spools or rollers are fitted to rotate
on their own axis. This thread or twine carrier receives its rotary motion from
the main shaft or spindle of the machine, or from a shaft or spindle arranged at the
side, or extending through the main spindle; this arrangement permits a differential
motion or difference of speed between the needle and the twine carrier.
I modify this portion of my said Invention by constructing a thread carrier and
controller of a series of rings confined in their proper position by rollers and springs.
The spring pressure is rendered variable to produce any required tension for drawing
up the stitches. The twine is carried outside the rings and passes between any
pair in line with the stitch being formed, and the slack twine is thereby taken
up.
The said Invention also comprises a series of scollops formed of any suitable
flexible or elastic material, such as vulcanized india-rubber, or a compound of india-
rubber and leather, or metal springs, or the like. This device is employed for
taking up and controlling the slack twine and producing the required tension in the
formation of stitches.
The said Invention also comprises a shield or twine guard for keeping the twine
from looping or kinking during the formation of the stitches.
It also comprises a changeable needle ring secured to the main socket ring to
permit the use of needles of different size in the said machine. This ring is sup-
ported on studs fixed in the main socket disc, and is furnished with adjustable
Pains 971

page_text: rollers. These rollers confine the needle within the groove of the aforesaid change-
able needle ring and diminish the friction of the needle.
It also comprises an arrangement of tension pulleys for tightening and relieving
the strap or band that drives the machine, and for starting and stopping the same.
The mechanism permits these operations to be effected by the foot of the attendant
or operator. In some instances I combine with the above a treadle for driving the
said machine by the foot.
The said Invention also comprises eccentric adjustable rollers for preparing the
edges of the cloth or material to be sewed in the said machine.
The said Invention also comprises the combination in an overedgo stitch sewing
machine of a four-motion or drop feeder with the top spring-presser foot, and a
crank for regulating the length of the stitches.
The said Invention also comprises the construction of a machine in which the
above devices are combined with each other and with the other parts of the said
machine, and with a suitable frame or stand in which the aforesaid treadles and
their connections are mounted.
The aforesaid improvements are also applicable to other overedge stitch
machines.