IMPROVEMENTS IN SEWING-MACHINES
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by William Edward Gedge at the Office
of the Commissioners of Patents on the 1st February 1883. A Communi-
cation to him from abroad by Edward Kohler, of Oakland, County of Alameda,
State of California, one of the United States of America, Gentleman.
WILLIAM EDWARD GEDGE, of N° 11 Wellington Street, Strand, London, in the
County of Middlesex, Patent Agent, "IMPROVEMENTS IN SEWING-MACHINES"
A Communication to me from abroad by Edward Kohler of Oakland, County of
Alameda, State of California, one of the United States of America, Gentleman.
This Invention relates to certain improvements in Sewing Machines, and it
consists in such a construction and combination of the mechanism constituting the
machine, as to enable the formation with it of a stitch from a single thread which
shall resemble and be equivalent to the over and over stitch used in sewing carpets
and grain sacks by hand.
In this machine a vertically moving straight needle is employed having an eye
in the point and carrying a single thread, which is led to it through a suitable
tension apparatus from the ball or spool upon which it is originally wound.
Below the table is a curved and nearly semicircular needle or hook, forked at
one end and having its other end secured to a shaft which is rotated so that when
the needle passes down through the goods, this forked hook passing to one side of
the needle, enters its point into the loop of the thread, and as the needle rises this
hook carries the bight of the thread around the edge of the cloth, and over its top,
so that when the needle again descends, it will pass through this bight, and
lock it.
A short arm which is oscillated at right angles with the curved hook by a shaft
from which it projects, retains the bight of the loop upon the forked cnd of the
hook until it has been carried up over the edge of the seam.
The construction and operation of this improved machine is as follows:-
Upon the top of the bed plate is an arm within which moves the lever to drive
the needle bar, this being actuated by a cam in the usual manner.
The needle bar carries a vertically moving needle having a single thread or twine
led to it from a ball or spool through suitable tension devices.
Beneath the table or plate is a shaft lying transversely and having secured upon
one end a semicircularly curved hook
One end of this curved hook is secured to the shaft, an 1 the other end has a
prong or fork which is carried by the semi rotation of the shaft in a sweep from
below the table to its upper side, passing around the edge of the goods which are
being worked.
The prong or forked end of this curved hook is below the table and withdrawn to
its farthest point when the needle passes downward through the goods until its
point is near the prong.

page_text: The rotation of its shaft now advances the prong, the longest point of which
enters the loop of thread, at the eye of the needle and advancing in an arc of a
circle as the needle recedes vertically, a loop or bight of the thread is left upon the
forked end of the hook.
This is carried forward by the hook and is prevented from slipping off by an
arm projecting from a shaft and moving upward as the hook moves, until the
latter has carried the bight of the thread up around the edge of the goods and over
the top, where it is directly beneath the needle, this having by this time attained
its highest point.
When it again descends it passes with its thread through the loop and thus locks
or fastens the stitch, at the same time forming another loop at the bottom of its
stroke to again receive the forked hook.
The fork of the hook enters the loop at one side of the needle below the table,
but its shaft is moved endwise as it rotates, so that the hook passes to the opposite
side of the needle above the table.
This is effected as follows:-
The Shaft which carries the curved hook has a pinion secured to it and a rack
bar engages the pinion. The rack bar is caused to reciprocate by the action of a
cam upon the main driving shaft and this movement of the rack rotates the pinion,
the shaft, and the curved hook as before described. The shaft passes through a
sleeve or a hole in a plate, and has secured to the end opposite the hook, a
short cylinder or collar having one end cut inclined.
A similarly shaped collar is secured to the plate, so that the inclined ends meet,
and when the shaft is rotated, the action of the inclines upon each other will cause
the shaft to move endwise, and this will carry the hook from one side of the
needle when below the table, to the opposite side above the table.
A spring serves to return the shaft as it reverses its rotation.
When the loop of twine or thread is taken from the needle, below the table, by
the advance of the forked hook, it is necessary to retain it upon the fork while the
latter is carried up to the edge of the goods in its movement in a circle from below
the table to its finishing point above it.
The loop is retained upon the hook by an arm projecting from a shaft, as before
described, so as to move upward in front of the hook until it has reached the edge
of the goods.
The rotation of the shaft is produced by forming its end in a twist or spiral,
which passes through a slot in a bar or lug secured to a slide which moves the
rack bar, and as this slide travels forward and back it acts upon the twisted end of
the shaft so as to produce a semi rotation, and the desired movement of the arm,
as the shaft is-supported and turns in stationary boxes. The feed mechanism is
similar to that ordinarily employed for sewing machines, and it is operated by
neans of a cam acting upon the feed bar.
I do not deem it necessary to explain here the operation of the presser foot,
needle bar and other details of construction found in ordinary sewing machines.
The stitch formed by this machine is peculiarly adapted for sewing any class of
work in which an over and over stitch is usually formed by hand, such as the
sewing of bags, carpets &c.
A tongue beneath the presser foot serves the purpose of making the thread or
twine chain out or continue the stitch when no goods are beneath the needle, so
that as one bag is completed, the stitch or chain will continue until another is placed
beneath the needle.