Improvements in Double Chain Stitch Sewing Machines.
Year: 1897

page_text: Date of Application, 18th May, 1897-Accepted, 3rd July, 1897.
[Communicated from abroad by THE SINGER MANUFACTURING COMPANY, of New
York in the United States of America, Sewing Machine Manufacturers.]
Improvements in Double Chain Stitch Sewing Machines.
I, WILLIAM HARVEY INSLEE, Manager of The Singer Manufacturing Company,
Kilbowie, Dumbartonshire, do hereby declare the nature of this invention and in
what manner the same is to be performed as communicated to me, to be particularly
described and ascertained in and by the following statement:-
My invention relates to double chain stitch sewing machines, and has for its
object to provide a machine of this class in which the loops of the looper thread
will be properly spread for the entrance of the needle without requiring the vibrating
looper to be moved laterally. To this end my improved looper is provided on its
side which comes adjacent to the needle, in taking a needle loop, with a curved
swell which terminates near the heel of the looper in an inclined shoulder behind
which shoulder the looper thread running from the eye of the looper to the work
falls and is held taut when the looper is in its extreme forward position, so that
on the backward movement of the looper the taut thread will be lifted slightly
and pushed laterally by the said swell into engagement with a small loop-detaining
hook on the underside of the throat-plate adjacent to the needle-hole and which
hook holds the looper thread in its lateral or spread position until the needle, on
its downward movement, has entered the distended loop or bight of thread, when
the continued backward movement of the looper will draw the thread from said
hook so that it will encircle the now rising needle and will thus be drawn up
into the work around the needle-thread as the stitch is tightened at the ascent of
the needle.
In the accompanying drawings Fig. 1 is a partial front end view of a sewing
machine embodying my Invention, and Fig. 2 is a partial plan view of the same.
Fig. 3 is a detail perspective underside view of the throat-plate. Figs. 4, 5, 6, 7,
and 8 are detail underside views illustrating the operation of the loop-spreaders
on the loopers and of the detaining hooks co-operating therewith.
A denotes a shaft to be rocked or oscillated in any suitable manner, and to which
are attached any desired number of eyed or thread-carrying loopers a, corresponding
to the number of needles with which the machine may be furnished. The loopers a
are each provided on their sides 2 which come adjacent to the needles, in taking
the needle loops, with outwardly curved or swelled portions 3 which serve as loop
spreaders and which terminate near the heels of the said loopers in inclined
shoulders 4. The throat-plate bis provided on its under side, closely adjacent to
the needle holes, with loop detaining hooks b', which point in a direction opposite
that in which the loopers point, and on which, during the first part of the backward
movement of the latter, the looper threads will be caught as will presently be
more fully explained, but from which said threads will be disengaged during the
latter part of the backward movement of the loopers after the needles have entered
the loops of the looper threads.
The rock-shaft A is provided with a take-up arm c arranged between and co-

page_text: operating with two vertically moving take-up eyes, at and d', operated from the
rock-shaft E which imparts horizontal and feeding movements to the feed bar e,
as in the well-known Singer oscillating shuttle machines. This feeding rock-shaft
I have provided with a horizontally extending arm e¹ engaging a fork in the end
of a lever or bar 1 pivoted at its other end on the feed-lifting rock-shaft E, said
lever or bar having a take-up eye d, just referred to, and a branch or fork of said
lever or bar having the other take-up eye. As the shaft E is rocked to impart
horizontal or feeding movements to the feed-bar the horizontal arm e¹ of said shaft
will cause vertical movements to be imparted to the take-up bar or lever D, and
these take-up movements will always be proportioned to the feeding movements
se that when the feed is varied the take-up action on the looper thread or threads
will be correspondingly varied, the movements of said take-up lever being shortened
when the feed is shortened and lengthened when the feed is lengthened.
For
clearness of illustration the feed-dog has been omitted in Fig. 2 and the feed-bar
partly broken away in Fig. 1.
•
The operation of my improved machine is as follows-When the needles have
descended to their lowest positions, and have risen slightly and thrown out their
loops in the usual manner the loopers (which vibrate forward and back
transversely of the machine, or in the direction of the feed) enter and carry their
own threads into said loops. When the loopers have reached their extreme forward
positions the inclined shoulders 4 of said loopers will have passed the needle holes
the throat-plate and the detaining hooks adjacent to the said holes, so that
the looper threads, running from the eyes near the points of the loopers up through
the needle holes to the work will have fallen behind the said shoulders and be held
taut. On the first part of the backward movements of the loopers the inclined
shoulders 4 will force the taut looper threads laterally on to the loop-spreading
portions or swells 3 of the loopers, and said threads will also be lifted slightly by
said swells or loop spreaders and caught upon the detaining hooks 6', and the loops
thus distended will be held by said hooks until the needles descend and carry
their threads into these distended loops of looper thread, and subsequently to this,
when the loopers are performing the latter part of their backward movements,
they draw their threads off from said detaining hooks, and the looper-loops, are then
tightened into the stitches.
My improved looper, vibrating transversely of the machine, or in the direction of
the feed is well adapted either for a single needle machine, or for a machine employ-
ing a plurality of needles in connection with a plurality of loopers, for making two or
more rows of stitches, and in illustrating my Invention herein I have shown it as
adapted for a two-needle machine.
It will be obvious, owing to the fact that I am enabled to properly spread the
loops of the looper thread without imparting lateral movements to the loopers,
that the looper operating mechanism is just thus far simplified, so that the
machine is capable of the very high speed now demanded for manufacturing
machines; and owing to the arrangement of the loopers so that they vibrate
transversely of the machine, or in the plane of the feed of the work, any desired
number of loopers co-operating with any desired number of needles, for simul-
taneously making a plurality of seams, may readily be employed.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed, I declare that what I
claim is
In a double chain stitch sewing machine, the combination with a needle, of a
rocking or vibrating eyed or thread-carrying looper a arranged to vibrate in the
plane of the feed of the work, said looper being provided with the laterally extending
loop-spreading portion 3 terminating near the heel of the looper in the inclined
shoulder 4, and a throat-plate provided with a thread detaining hook, as b¹,
adjacent to the needle-hole, and which hook points in a direction opposite to the
said looper, or approximately so, said shoulder being located far enough forward

page_text: of the shank of the looper so that the looper-thread can pass behind the same when
the looper moves to its extreme forward position, and so that the looper thread
will be spread laterally and engaged with said detaining hook by said loop-
spreading portion and shoulder; whereby the needle and looper threads may be
properly concatenated for the formation of a double chain stitch seam without
requiring lateral movements of the looper, substantially as described.
Dated this 17th day of Anril 1897
WALLACE FAIRWEATHER,
Of the Firm of Cruikshank & Fairweather,
Chartered Patent Agents,
62 Saint Vincent Street, Glasgow, Agent for the Applicant.