Improvements in Lock-stitch Sewing Machines.
Year: 1897

page_text: Date of Application, 19th Jan., 1897-Accepted, 1st May, 1897
Improvements in Lock-stitch Sewing Machines.
1, 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 lock stitch sewing machines in which the
loops of needle thread are carried around the lower or locking thread by a
rotating hook, and my invention has for its object to provide a machine, of the
class referred to, which is adapted for high speeds, and which will be light-running
and comparatively noiseless.
In my improved machine the lower thread is contained in a bobbin case or
stationary shuttle centrally supported by reciprocating pins placed on opposite
sides of said bobbin case or shuttle and alternately movable in and out of the
latter to permit of the passage of the loops of needle thread, one limb of each loop
passing by the centre of the bobbin case earlier than the other limb thereof,, and
one reciprocating supporting pin entering the bobbin-case as the other is withdrawn
therefrom, so that said bobbin case is always sustained vertically by one or the
other of said pins, suitable stationary supports on opposite sides of said bobbin-case
holding the latter in place vertically. The rotating hook by which the loops of
needle-thread are carried around the bobbin-case has lateral or horizontally
reciprocating movements, so that the loops of needle thread, which are taken from
the needle at the rear side of the bobbin-case, are spread laterally by the recipro-
cating movement of the rotating hook, so as to be suitably enlarged sidewise for
easy passage around the bobbin case.
In the accompanying drawings
Fig. 1 is a sectional elevation of my improved machine, the feeding mechanism
being omitted for greater clearness.
Figs. 2 and 3 show a portion of the lower part of the machine with the parts in
different positions.
Fig. 4 is a plan view of the hook, bobbin-case and adjacent parts.
Fig. 5 is a front end view of the machine.
Fig. 6 is a side view of the bobbin-case, and bobbin, and
Fig. 7 a detail to show connection of the bobbin-pin frame with the hook-shaft.
A denotes the base of the frame-work of the machine, and A' the bracket arm
thereof. Journalled in the base A is. the rotating driving shaft B having, as
herein shown, three cranks 6 connected by three pitmen b' with three cranks c with
which the needle operating shaft C is provided, so that the latter shaft will be
rotated from the former. With this crank and pitman connection shown either
shaft might be the driving and either the driven shaft, as will be understood. Dis
the needle-bar operatively connected, in any suitable manner, with the forward end
of the shaft C and carrying the usual eye-pointed needle d. The shaft B is

page_text: provided with a disc 62 in which is jointed a link e, and e¹ is a pitman jointed at its
rear end to the forward end of the link e, said pitman being jointed at its forward
end to a link e which is, in turn, pivotally attached to the rear end of the sliding
and rotating shaft F supported in suitable bearings in the base A and carrying the
hook disc. The pivots or joints by which the link e is connected to the disc b
and the pitman, as likewise the joints by which the link eis connected with said
pitman and with the shaft F are at right angles to each other, thus affording
universal joint connections between the shafts B and F which permit of a sliding
or end wise movement of the latter in addition to its rotating movement, the said
shaft F being higher than the shaft B, so as to be out of line with the latter to
secure a sliding movement of the said shaft F of proper extent.
G is the bobbin-case or shuttle and g is the bobbin enclosed therein and from
which the lower or locking thread is supplied, said bobbin-case being loosely held
between the arms h of a stationary holder H secured by a set screw to a fixed
pin 2. Connected with the shaft F, to reciprocate therewith, is a frame i carrying
two pins and placed on opposite sides of the bobbin-case G, the latter having
through it and through the pin g on which the bobbin is journalled a hole g² to
receive said pins. The distance between the adjacent ends of the pins i, i, is
somewhat less than the thickness of the bobbin-case so that, in the operation of the
machine, one or the other of said pins is engaged with said bobbin case to support
the latter vertically.
To permit the bobbin case to be placed in or removed from working position the
pin is attached to a slide 2, removably secured in position in a tubular portion
of the frame. I by means of a spring which engages said slide by a notch 2³
formed in the latter. When the spring is lifted the slide 2 may be drawn out to
disengage the pin ¹ from the bobbin-case, and if this be done when the pin i is
disengaged from the said bobbin-case the latter will be free to be removed from
working position, and may be inserted in place in the machine when the pin ¿¹ is
thus withdrawn. The frame I is, in the form of my invention. herein illustrated
steadied by means of an arm depending from the tubular part 3 of said frame,
and having a sleeve adapted to slide back and forth on a fixed rod J.
To hold the bobbin-case G from turning ou the pins i and the hole g²
on the
said bobbin-case is preferably. made square or of any polygonal or irregular
form, and the said pins are of corresponding form in cross-section, to fit
said hole.
The needle d is arranged to descend on the rear or right-hand side of the bobbin-
case at which position the loops of needle thread are taken by the beak fl of the
laterally moving rotary hook 2, and as said hook continues its forward rotary
movement after having taken a loop of needle thread it will also move towards the
left, or towards the front end of the machine, and will thus open the loop laterally
and carry the front or left limb thereof over the front side of the bobbin-case.
The hook is provided at its front edge, rearward of the beak, with an inclined
rib which serves to hold the rear or right-hand part or limb of the loop of
needle thread towards the rear side of the bobbin-case while the beak f' is carrying
the left part or limb of said loop around the front of said bobbin-case, and thus the
loops of needle-thread are positively opened or spread for easy passage around the
said bobbin-case, this action being assisted by a small loop-dividing flange or
peripheral projection 9 with which the bobbin-case is preferably provided.
Owing to the arrangement of the shaft F out of line from and considerably
above the driving shaft B and the connection of said shafts by the links e and e
and pitman e¹ I am enabled to impart an irregular or differential sliding or lateral
movement to the shaft F. Thus when the parts are in the position shown in Fig. 1
with the free end of the link e swung upward or inward towards the centre of the
shaft B the shaft F will be at its extreme inward position, and for about one-
quarter of a revolution of said shaft B both before and after the parts are in the
position just referred to the endwise movement of the shaft F will be but very
slight, owing to the nearness of the free end of the link e to the line of the centre

page_text: of the shaft B, and the parts are so timed that the loops of needle thread are taken
from the needle while this slow end wise movement.of the hook-carrying shaft F is
occurring, and at about the end thereof; or, in other words, at about the termination
of what may be termed the "dwell" in the lateral movement of the rotary hook,
and thus any danger of collision of the laterally moving rotary hook with the
needle is avoided, this danger being also provided against by the inclined or
rearwardly or retreating front edge portion f of the hook f. After a loop of
needle thread has been taken by the beak f¹ of the hook the latter moves rapidly
laterally to spread the said loop, said hook passing from the loop-seizing position
shown in Fig. 3 to its extreme outward position shown in Fig. 2 during about one-
third of a revolution of the driving shaft B.
Any suitable feeding and thread controlling devices may be employed_in
connection with the novel features of my machine hereinbefore described. For
clearness of illustration the feeding mechanis n of my machine has been omitted
from the accompanying drawings.
The thread controlling devices of my machine, as herein shown, consist of an
ordinary disc tension K, a take-up arm L, and a slack-controlling lug M recipro-
cating with the needle-bar and having an eye m through which the thread runs
in passing from the eye of the take-up to the needle.
The operation of my machine is as follows: When the needle has descended to
its lowest point and has risen slightly and thrown out a loop the latter is seized by
the beak of the hook and one limb of said loop is, by the rotary and lateral
movement of said hook, carried around the front side of the bobbin-case and past
the centre of the latter, the pin being at this movement withdrawn from the
bobbin-case to let the thread pass, and the said pin ¹ is then engaged with, the
bobbin case and the pin i withdrawn therefrom to permit the rear limb of
the needle loop to pass as the said loop is drawn up by the take-up. The bobbin-
case G is preferably placed eccentric to the hook-carrying disc f, so that the
loops of needle thread will pass around the centre thereof earlier than they
otherwise would.
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 lock-stitch sewing machine, the combination with a needle and its
operating mechanism, of a stationary device or bobbin-case from which the under
thread is supplied, a laterally or end wise moving rotary shaft and a rotary hook
carried by said shaft and provided with a loop-seizing beak and with an inclined
peripheral rib rearward of said beak.
2. In a lock-stitch sewing machine, the combination with a needle and its
operating mechanism, of an end wise movable rotary shaft, a rotating hook carried
by said shaft, a stationary bobbin-case or device from which the under thread is
supplied and which is provided with a transverse hole, and two reciprocating
supporting pins placed on opposite sides of said bobbin-case or device and one or
the other of which is, in the operation of the machine, in engagement with the said
5 bobbin-case or device, to support the latter vertically.
3. In a lock-stitch sewing machine, the combination with a needle and its
operating mechanism, of a rotating and end wise movable shaft, a hook carried by
said shait, a stationary bobbin-case or device from which the under thread is
supplied and which is provided with a transverse hole, and two reciprocating
0 supporting pins placed on opposite sides of said bobbin-case or device and one or
the other of which is, in the operation of the machine, in engagement with said
bobbin-case or device, to support the latter vertically, said pins being of a form
other than round, to hold said bobbin-case or device from turning.
4. In a lock-stitch sewing machine, the combination with a needle and its
$5 operating mechanism, of the rotary and endwise movable hook-carrying shaft F, the
shaft B having a crank or disc b and placed out of line from the shaft F, the link e

page_text: pivoted to said crank or disc, the link.e pivoted to the rear end of said shaft F,
and the pitman el jointed to said links by pivots which are at right angles to the
pivots by which links are connected to said crank or disc and said shaft F,
respectively.
Dated this 18th day of January 1896.
WALLACE FAIRWEATHER,
Of the Firm of Cruikshank & Fairweather,
Chartered Patent Agents,
St. Vincent Street, Glasgow, Agent for the Applicant.