Improvements in Double-loop Stitching Machines.
Year: 1897

page_text: Date of Application, 6th Apr., 1897-Accepted, 21st Aug., 1897
[Communicated from abroad by THE SINGER MANUFACTURING COMPANY, of New
York, United States of America, Sewing Machine Manufacturers.]
Improvements in Double-loop Stitching 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 that class of sewing machines which form the double chain
or "Grover and Baker" stitch, and has for its object to provide a machine, of the
class referred to, which will be simple in construction, so that it will be inexpensive
to make, and in which the movements are strong and positive so that the machine
will be capable of running at high speed and with but little noise.
In the drawing Fig. 1 is a side view, partly in section, of my improved machine.
Fig. 2 is a sectional view at the forward end of the work-supporting arm on a
larger scale than in Fig. 1.
Fig. 3 is a front end view of the machine with the face plate removed.
Fig. 4 is a detail view of the lower thread take-up device.
Figs. 5 and 6 are detail views to show the trimming blades.
Figs. 7 and 8 are detail views of the feeding mechanism.
Figs. 9 and 10 are enlarged views of the rear portion of the machine shewing the
take up device.
The frame work of the machine consists of the base A, the standard A¹, the
overhanging arm a having the head a¹ at its forward end, and the lower or
work-supporting arm a². For some kinds of work a flat work plate is desirable and
this "arm
"machine inay be converted into a bed plate machine by means of the
flat work-plate a³ having a yoke at by which and the set screws a' said work-plate
may be removably attached to the arm a².
B is the driving shaft journalled in the lower part of the frame work and provided
near its rear end with an eccentric connected by a pitman c to the rear end or arm of
the needle operating lever C to the forward end of which the needle bar c¹ is
connected to be reciprocated vertically in the head a', said needle bar carrying the
usual eye-pointed needle c².
D is a small rock shaft journalled in a bearing in the forward end of the arm a²
and having an upwardly extending arm d which supports a sleeve e having a
rounded or ball like portion e¹ to prevent binding at its point of connection to
the arm d. The needle operating needle C has a depending arm c³ to the lower
end of which is jointed the rear end of a rod E carrying at its forward end the
thread carrying looper e², said rod E passing through the sleeve e. The
rock-shaft D is provided at its forward end with an arm d¹ slotted to embrace an
eccentric b¹ on the forward end of the driving shaft B, so that rotation of said
driving shaft causes a rocking movement to be imparted to the shaft D, and
thus the looper carrying rod E, passing through the sleeve e carried by the
arm d of said rock shaft, will be moved to and fro laterally by said arm ag

page_text: said rod is reciprocated longitudinally, by reason of its connection with the arm c³
of the needle lever; thus causing the looper e² to be moved forward on one side
of the needle and backward on the other side thereof, as is usual in double chain
stitch machines.
To the arm of the rock shaft D is attached a plate d² having a finger d³ which,
as the needle is rising, is moved against, or closely adjacent to the front side of said
needle to throw out or open the loop of needle thread on the rear or opposite side of
the needle, so that the loop will be entered with certainty by the looper e² which
moves forward, as the needle rises, on the side of said needle opposite to that on
which said loop forming finger d³ is placed.
The shaft B is provided with an eccentric be embraced by a yoke F having a
slotted arm f pivoted at its lower end to an arm g fast on the rear end of a tubular
rock shaft G surrounding said shaft B and provided at its forward end with a second
rigid arm g. The slot of the arm f is entered by a pin or roller stud to be carried
by a feed regulating lever H pivoted at h to a part of the machine frame, and
provided at its outer end with a inilled set nut h² to hold said regulating lever in any
desired position of adjustment.
The arm g¹ is embraced by lugs i on a horizontally movable block or slide I, said
lugs entering a horizontal guide groove a in the front end of the arm u². The
block or slide I is recessed for the reception of a block K vertically movable in said
block I and carrying the feed dog k. The block K is provided with a horizontal
slot k¹ in which the eccentric b¹ works, said eccentric thus serving to impart positive
up and down movements to the feed block K and the latter being moved back and
forth horizontally with the block I which is operated positively in both directions by
the arm g¹ of the rock shaft G. This construction secures a strong and positive
square" four-motioned feed well adapted for a high speed machine.
67
The needle thread passes from the tension device L through thread take-up eyes m
formed in plates m¹ carried by the needle bar c' and working on opposite sides of a
bar n provided with an opening in which is placed a check tension spring n¹ pressing
lightly against the inner wall of the opening in the bar n, so that the needle thread
passing through said opening from one to the other of the eyes in the plates m³ will
be momentarily detained by said spring when the needle is descending, and the
slacken will thus be controlled so that the thread will not get in the way of the
point of the needle. This needle-thread controlling mechanism is substantially
the same as that which has long been in use in the Willcox & Gibbs machine, and its
operation is therefore familiar to those skilled in the art to which my invention
relates.
Co-operating with the above described controlling device for the needle thread is a
novel take-up device for the looper thread which I will now describe. Attached
to the lower end of the arm of the needle bar operating lever C is a take-up
device consisting preferably of a wire loop r bent at right angles to form a shoulder
; and supported by a housing plate P is a second wire loop p, said plate P having
an opening or slot p₁ through which the said loop r extends and in which it
reciprocates when the machine is in operation. S is a bent plate attached to the
base A outside of the plate P and having a horizontal portion extending inward
through the slot or opening p¹ of the said plate P; said horizontal portion of said
plate S having an inclined slot s which is so arranged relative to the path of
movement of the shoulder r¹ of the loop r that as said loop is reciprocated with the
arm of the needle-bar operating-lever, and with the looper operating rod E
connected with said arm, said shoulder will cross from the inner to the outer side of
said inclined slot.
The looper thread runs from the tension device L¹ to the forward side of the upper
limb or bar of the loop p, thence through said loop around rearward of the loop and
down through the inclined slot 8 of the plate S and thence forward below the said
loop and against the front edge 8' of the plate S and again through the loop p to
to and through the hollow work-supporting arm a² to the looper e² working in said
Thus as the said looper is making its backward movement, after having passed
arm.

page_text: its thread through a loop of needle thread, the slack of the looper thread is taken up
by the wire loop take-up device r during a portion of the backward travel of the said
looper; but when in the backward movement of the said take-up device the shoulder "l
thereof crosses over fa: enough to the front side of the inclined slots of the plate $
to permit the thread to escape past said shoulder into said slot, the thread will be
momentarily slackened so that the stitch will not be drawn too tight, and thus a
slack or elastic stitch seam, suitable for knit goods will be produced. As the
thread, after escaping past the shoulder of the upper limb of the wire loop 7, will
still be held by the lower limb of said loop (owing to the direction the thread takes
in running from said loop upward and forward past the front edge s¹ of the plate S)
the thread will be restored to proper position to repeat the above described operation
when the take-up loop r moves forward in unison with the looper.
It will thus be seen that I not only provide a take-up device for the lower thread
which is moved in unison with the looper, but I also provide a take-up device which
is, in a measure, intermittent in its action, so that a slack stitch seam may be
produced.
The timing of this slackening of the take-up action of the looper thread may be
varied by providing interchangeable plates S having slots s of varying inclinations,
or by any suitable or well-known means of adjustment of the plate S, as will be
readily understood.
My improved machine is preferably provided with a trimming mechanism which,
as herein shown, consists of a blade q carried by the trimmer bar Q connected to an
arm at the forward end of a rock shaft T journalled in the overhanging arm A and
having an arm at its rear end connected by a pitman t with an eccentric on the
driving shaft B. The throat plate W is provided with a removable stationary blade w
co-operating with the movable blade q in the usual manner.
The hollow work-supporting arm a² is open at its top for access to the looping
mechanism and is provided with a longitudinally extending cover plate U hinged at
its rear end at u to the machine fraine at the rear end of said arm, said hinge being
transverse to said arm so that said plate may be lifted as denoted by dotted lines in
Fig. 1.
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
1. In a double chain stitch sewing machine, the combination with the needle bar
and its operating lever C, having the depending arm c³, of the looper rod E connected
to said arm, the looper carried by said rod, the short rock-shaft D at the forward end
of the work-support and having a jointed support through which said rod extends
and in which it reciprocates, and means for positively rocking said shaft in both
directions to impart positive back and forth lateral movements to said looper rod and
looper.
2. The combination with the needle-bar c¹, of the operating lever C having the
depending arm c³, the looper rod E jointed at its rear end to said arm and provided
at its front end with the looper e², the rock-shaft D having the arm d and the forked
arm d', the sleeve e through which said looper rod extends and which is jointed to
and supported by said arm d, and the driving shaft B having an eccentric 6' working
in the fork of the said arın d¹ and serving to impart positive movements in both
directions to said rock-shaft.
3. In a double chain stitch sewing machine, the combination with a needle and a
looper and their operating mechanism, of a looper thread take-up device movable in
unison with the said looper, as the latter is reciprocated longitudinally, said take-up
device having a cast-off shoulder, and a plate having an inclined slot through which
the looper thread runs, said inclined slot being so arranged as to cross the plane of
movement of the said cast-off shoulder on said take-up device.
4. A take-up mechanism for double chain-stitch sewing machines consisting of the

page_text: combination with the needle-bar operating lever having the depending arm c³, of the
wire loop or device r attached to said aim and having the shoulder r, the plate P
having the slot or opening and the wire loop p, and the plate S having the inclined
slots so arranged as to cross the plane in which said shoulder travels as said loop or
device is moved back and forth with said aim c³.
5. The combination with the driving shaft B having the eccentric 62, of the
yoke F embracing said eccentric and having the slotted arm f, the rock-shaft G
having an arm g to which said aim f is pivoted near the end of the latter, said
shaft G having at its for ward end the am g¹, the feed regulating lever H pivoted to
the machine frame and having a pin or stud extending into the slot of the arm f,
the horizontally movable block or slide I having lugs or parts embracing a portion of
the said arm g¹, the slide or block K vertically movable in the said slide or block i
and carrying the feed-dog k, and the eccentric b' for imparting vertical movements to
the said slide or block K.
6. The combination with the needle-bar c¹, of the operating lever C having the
depending arm c³, the looper rod E jointed at its rear end to said aim and provided
at its front end with the looper e², the rock-shaft D having the rear arm d and the
front forked arm d, the latter being provided with the plate d having the
loop-forming finger which extends past the needle on the side thereof opposite to
that from which the said looper takes the loops of needle thread, the sleeve e through
which said loop er rod extends, and which is supported by said arm d, and the driving
shaft B having the eccentric bl working in the fork of the said arm and serving to
rock said shaft D.
Dated this 5th day of April 1897.
WALLACE FAIRWEATHER,
Of the Firm of Cruikshank and Fairweather,
Chartered Patent Agents,
62, Saint Vincent Street, Glasgow, Agent for the Applicant.