Improvements in Sewing Machines.
Year: 1896

page_text: Date of Application, 7th Jan., 1896-Accepted, 8'h Feb., 1896
[Communicated from abroad by THE SINGER MANUFACTURING Co., of New
York, United States of America, Sewing Machine Manufacturers.]
Improvements in 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 :-
This invention has for its object to provide a sewing machine for making the
double-chain or "Grover & Baker" stitch, said machine being simple in construc-
tion and strong and positive in operation, so as to be capable of being run at high
speeds, and being provided with means whereby the upper and lower threads will
at all times be properly controlled.
In the drawings
Fig. 1 is a sectional side view of a sewing machine embodying the inven-
tion. Fig. 2 is a front end view of the same, partly in section on line 2-2,
Fig. 1.
Fig. 3 is a sectional view on line 3-3, Fig. 1, the frame-work or arm of the
machine being mostly omitted.
Fig. 4 is a detail view of the toggle for operating the looper-carrying bar.
Figs. 5 and 6 are detail plan views, with the parts in different positions, of a
portion of the mechanism in the forward part of the work-supporting arm or
cylinder.
A denotes the bracket arm and B the work-support, herein shown as being in
the form of an arm or cylinder to adapt the machine for use in sewing tubular or
hollow articles. Journaled in the upper part of the bracket arm A is the main or
driving shaft C having at its forward end a crank e connected by a pitman d with
the needle bar D, said shaft having near its rear end the crank to which is
connected a pitman E forked at its lower end to form the yoke e and to which
latter is jointed the central part of a toggle consisting of the links e and e².
The link el is jointed at its rear end to a yoke of a stud f1 fitted to rock in a
suitable bearing in the frame of the machine but held from endwise movement, as
by a collar fixed to said stud outside of its bearing. The link e2 is jointed at its
forward end to a yoke g of a sliding and rocking looper-operating bar G having
near its forward end a vertical arm h carrying the eyed or thread-carrying looper i,
the latter being herein shewn as being integral with the arm h, and with a curved
thread-controlling arm 3. To the arm his attached, by a screw, a bar consisting
of the inclined, forwardly extending feed lifting and lowering arm and the
rearwardly extending arm 2 having a slotted thread-eye ³.
From the above described construction of the connections of the crank c' with
bar G it results that the vertical throw of said crank will cause the toggle formed
by the links e and to be alternately straightened out and bent, and as the rear
connection of said toggle is a fixed one the forward end thereof will move
horizontally, thus imparting a longitudinal sliding movement to the bar G. A. bali
joint at e, between the crank c' and the upper end of the pitman E, permits the
lower end of said pitman to vibrate slightly longitudinally of the machine without
causing binding of the parts at the connection of said crank and pitman. The lateral
throw of the crank is imparted to the bar G through the yokes e and g and

page_text: toggle link, thus imparting rocking movements to said bar to move the looper
laterally to cause it to pass forward on one side of the needle and backward on the
other side thereof.
The driving shaft C is provided, adjacent to the crank c', with an eccentric
embraced by a yoke k at the upper end of a connecting bar K jointed at its lower
end to a stud m carried by a crank arm m of a rocking feed shaft M within which,
in the form of the invention herein shown, slides and rocks the looper-operating
bar G, said feed shaft M having near its forward end an upwardly projecting
arin m² grooved or recessed to receive the block n provided with the serrated feed
dog or surface w', said block having a slot in which works the inclined arm '
on the looper-carrying arm or projection to cause the block to be raised and
lowered in the arm w; the rocking movements of the shaft M imparting forward
and backward movements to the feed block, as will readily be understood.
The rocking movements of the shaft M, to regulate the feed, are varied by the
feed-adjusting bell-crank lever O pivoted to a lug a in the bracket arm A, said
lever being connected with the har K by the link e. This feed-regulating
feature is not of my invention.
The feed rock-shaft M is provided with a thread-controlling arm m³ having
perforated lugs m' through which the looper thread is passed and in a line between
which lugs extends the thread-controlling arm moving with the sliding and
rocking looper-operating bar G. As the parts are so timed that the rocking move-
ments of the bar G and shaft M are in opposition to each other a bight or loop of
thread passing through the thread eye in one of the lugs in, partly around the
arm, and then through the thread eye in the other of the lugs m (on its way to
the thread eye and thence, through the eye or guide , to the looper i) will be
enlarged to take up the slack and tighten the suitch as said arms m³ and recede
from each other in their opposite rocking movements, this action occurring when
the looper is moving backwards after its loop has been taken by the needle; aud
the take-up netion of the backwardly moving arm being increased by its
horizontal curvature away from the arm m³, the thread being engaged by the
convex surface of said arm. From the fact that the take-up action of the thread-
controlling arm m³, moving with the rocking feed-shaft M, is in proportion to the
length of the stitches, resulting from the length of feed, it will be apparent that
the take-up for the lower-thread, varied with the feed, is an important novel feature
of the machine.
The needle thread running from the spool on the spool-pin J through the
tension device I to the needle d passes through a controlling device consisting, as
herein shown, of a light spring p attached to the bar p' secured to the head A' of
the machine, and a slotted eye y carried by a collar y' attached to the upper end
of the needle-bar D, the thread running over a guide-rod r the shank or support
of which is also secured to the said head A'. When the needle bar and needle
rise the thread is lifted by the lower wall of the slot of the eye so as to be
brought beneath the spring p, and thus when said needle again descends the slack
thread will be held up until the eye of the needle has reached the work, when the
upper wall of said slot will engage the thread and draw it downward free from the
spring p, leaving it properly slack for the formation of the loop. The lower
thread, on its way to the looper i, passes through a tension device L.
In the operation of the machine the needle descends, and as it rises and throws
out a loop the latter is taken by the looper which advances on
needle and retreats, when the needle is again descending, on the other side of the
needle, thus carrying its thread around the needle so that the latter, at each
descent, enters a loop of needle thread, and thus the needle and looper threads are
alternately interlooped, making double-chain stitches.
It will thus be seen that by the construction and arrangement of the parts.
herein shown and described I am enabled to impart sliding and rocking movements
to the looper-carrying har, which is beneath the work-plate, from a rotating shaft
located in the upper part of the arm of the machine, and it will also be seen that

page_text: I utilize the rocking movements of the feed shaft and looper-carrying bar, as also
the longitudinal movements of the latter, in controlling or taking up the slack of
the looper thread, thereby providing an efficiently operating machine consisting
of comparatively few parts; and as the feeding and looper movements are all
positive the machine is well adapted for high speed.
I do not wish to be understood as limiting the invention to the details herein
shown, as such details may be varied widely without departing from the essential.
principles of the invention. For example, the sliding and rocking looper-
operating bar might be arranged beside or outside of the rocking feed shaft, or a
feeding mechanism different from that herein shown, might be employed in
connection with the improved looper mechanism.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a double-chain stitch sewing machine, the combination with a rotating
driving shaft provided with a crank, of a thread-carrying looper, a bar for operating
the same, a toggle to impart longitudinal or sliding movements to said bar, a
pitman connecting said toggle to said crank so as to cause the toggle to rock and
thus impart lateral movements to the said looper in addition to its longitudinal
movements, and a needle-bar and needle also operated from said shaft.
2. In a double-chain stitch sewing machine, the combination with a rotating
driving shaft journalled in the upper part of the arm thereof and provided near
its rear end with a crank, of a needle bar operatively connected to the forward
end of said shaft, a bar placed below the work-plate of the machine and having
at its forward portion a thread-carrying looper, a toggle, one end of which is
fixed and the other end of which is connected to the rear end of said bar, and a
pitman connecting said crank to said toggle to cause sliding or longitudinal and
rocking movements to be imparted to said looper-carrying bar.
3. In a double-chain stitch sewing machine, the rotating driving shaft C
journalled in the upper part of the arm thereof and provided near its rear end
with the crank c, and the needle-bar operatively connected to the forward end of
said shaft, of the pitman E connected at its upper end to said crank and provided
at its lower end with the yoke, the toggle links e and connected to said yoke,
one end of said link e' being fixed to the frame work of the machine, the sliding
and rocking bar G to the rear end of which the forward end of the toggle link e
is jointed and the looper i carried by said bar.
4. In a double-chain stitch sewing machine, the combination with a needle bar
and needle and a longitudinally and laterally movable thread-carrying looper, of
a thread-controlling arm laterally movable with said looper, a rocking feed shaft
provided with a thread controlling arm, and operating mechanism for said parts
whereby said needle-bar is actuated and whereby also rocking or lateral movements,
in opposition to each other, are imparted to said thread-controlling arms.
5. In a double-chain stitch sewing machine, the combination with the rocking
and sliding bar G, of the arm h, the looper i carried by said arm and which latter
is also provided with the thread-controlling arm 3, the rocking feed shaft M
provided with the thread-controlling arm m³, and operating mechanism whereby
rocking movements, in opposite directions, are imparted to said bar and shaft and
whereby also said bar is reciprocated longitudinally.
6. In a double-chain stitch sewing machine, the combination with the rocking
and sliding bar G having the arm h, of the looper i carried by said arm, the
latter being provided with the horizontally curved thread controlling arm i³, the
rocking feed-shaft M having the thread controlling arm m³ provided with
the lugs m perforated to forin thread eyes, and operating mechanism whereby
rocking movements, in opposite directions, are imparted to said bar and shaft and
whereby also said bar is reciprocated longitudinally.
7. In a double-chain stitch sewing machine, the combination with a rocking feed

page_text: shaft, having an arm, and a feeding device movable horizontally with said arm
but fitted to move vertically independently thereof, of a sliding and rocking looper-
carrying bar provided with an inclined arm to engage said feeding device and
impart vertical movements thereto, and operating mechanism for said feed shaft
and looper bar.
8. In a double-chain stitch sewing machine, the combination with a thread-
carrying looper and a feeding device, of a lower-thread take-up device movable
with the feed and thus serving to take up an amount of slack thread in proportion
to the length of the stitches being formed.
Dated this 6th day of January 1896.
WALLACE FAIRWEATHER,
Chartered Patent Agent,
62 Saint Vincent Street, Glasgow, Agent for the Applicant.