Improvements in Sewing Machines.
Year: 1890

page_text: Date of Application, 22nd May, 1890-Accepted, 28th June, 1890
COMPLETE SPECIFICATION.
Improvements in Sewing Machines.
I ELI WILLIAM BROADBENT, Merchant's Clerk, of No. 261 Broadway in the City
of Now York in the State of New York, United States of America, do hereby declare
the nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
This invention relates to an improvement in sewing machines, and more particularly
to the feed and stitch forming mechanism of a single thread or loop stitch machine,
the object being to simplify such mechanisms, materially reduce the friction of the
operating parts, and to provide adjustments by which the machine will be adapted to
all kinds of work.
A practical embodiment of the invention is shown in the accompanying drawings,
in which Fig. 1 is a view of the machine in front elevation.
Fig. 2 is a view of the same in vertical longitudinal section.
Fig. 3 is a view in end elevation, showing the work plate in section, for the purpose
of more clearly illustrating such a feed mechanism.
Fig. 4 is a view in end elevation of the right hand or heel end of the machine.
Fig. 5 is a similar view, with certain parts removed, to more clearly show the
operating mechanism.
Fig. 6 is a similar view, showing certain parts removed, and other parts in
operating adjustment.
Fig. 7 is an enlarged view in detail, showing the feed bar at the limit of its forward
and upward adjustment, and the looper in its position relatively thereto.
Fig. 8 is a similar view, showing the feed bar at the limit of its rearward adjust-
ment, and the looper in its position relatively thereto.
Fig. 9 is an enlarged view in detail of the looper hook.
Similar letters of reference designate corresponding parts in all the Figures.
A represents the frame of the machine, having the upper branch a and lower
branch a'; B the driving shaft journalled in suitable bearings at the opposite ends of
the upper branch a; C the reciprocating needle bar seated in adjustable bearings c,
and driven by a crank on the end of the driving shaft B; D a balance wheel on
the heel end of the driving shaft ; and d the spool support.
The looper, in the present improvement, is formed by means of a hook E of peculiar
construction, fixed on what may be termed the looper shaft F, journaled in a hollow
shaft hereafter termed the feed shaft F', the latter journaled in suitable bearings at
the opposite ends of the lower portion or branch a¹ of the main frame. The looper
shaft F is given a rocking motion by means of a cam 6', fixed near the heel end of the
driving shaft B.. The connection between the cam 6' and the shaft F is made by a
vertically reciprocating bar 6, preferably of triangular form, as shown, and seated in
or between the adjacent edges of vertical guides 6, one of said guides being adjustable
toward and away from the other conveniently by means of set screws 6, which secure
it to the frame, for taking up any wear. The upper end of the bar bis provided
with a loop b³, within which the cam 6¹ rotates, and the lower end of said bar & is
provided with a lateral and downwardly extending arm 66, which has a loose con-
nection with an arm ', fixed to the shaft F. Said loose connection may conveniently
be formed by providing the arm 6' with a slot 68, and the arm 6 with a stud 6º
adapted to enter the slot 68. In order to hold the loop 6 out of engagement with the
cam during such part of the revolution of the shaft B as is not required to actuate
the looper shaft F, and to ensure the retention of the hook in position to receive the
needle through the loop formed thereon, as will be hereinafter more particularly
explained, a spring G is seated in a recess g at the heel of the frame A, in proximity

page_text: to the reciprocating har 62, and is engaged by a stud or pin g¹ fixed to the bar 6º, the
tension of which spring tends, at all times, to press the bar toward the upward limit
of its stroke.
The looper hook E is provided with a thin point e, adapted to move forward in
close proximity to the needle H, between it and the thread, which it brings down with
it, and a short distance back from its point, said hook gradually increases in thickness
at its lower portion, as shown at e', while the thin portion extends for a considerable
distance back at the top of the hook, so that an oblique shoulder e³ is formed across
the side of the hook. The effect of this structure is, that as the hook noves rearward
between the thread and needle, it will carry the loop of thread into the bight es of the
hook, and, because of the thickened portion along the lower edge of the hook, will
spread the loop of thread, leaving a space between the said thread and the thinner
upper portion of the hook in the immediate neighborhood of the shoulder e², so that
as the needle descends, the hook at the same time gradually receding towards the
front, its point will follow along the thin portion of the hook, near the shoulder e³,
and will pass through the loop which surrounds the hook. Of course it is understood
that the rotation of the driving shaft B which reciprocates the needle, is so timed with
respect to the rocking of the looper shaft by the means particularly described, that the
hook will advance to the rear, just as the needle dwells at the lower limit of its stroke,
thereby receiving the thread on to it, and will then rest in that position until the
needle returns for the next stitch, and will then recede toward the front as the needle
follows along down the side of the thin portion. By this simple arrangement, it is
possible to do away with any other guide than the hook itself, and as this moves
through a very short distance of arc, it follows that its shaft F, will be required to
make only a very limited rocking movement, and hence the wear from friction will be
extremely slight.
In connection with such movements of the looper and its shaft, the hollow shaft F¹,
within which the looper shaft F, is seated, is caused by a simple rocking movement to
operate the feed as follows:-
The feed consists in a serrated jaw K, having, in its shank, a vertically elongated
slot k, through which, by means of a set scrow k¹, it is secured to the feed bar L in
vertical adjustment. Such vertical adjustment of the feed jaw is very important, in
that it admits of throwing the serrated face of the jaw upwardly and downwardly
through the work table I, so as to bring it into a stronger or lighter engagement
with the goods, as may be desired, and thus feeding heavy goods positively along the
table, and at the same time providing against defacing thinner and more delicate
goods. The feed bar L is provided at or near its rear end with an elongated slot 1,
through which, by means of a screw ', it is pivotally secured to a stationary
support M at the end of the lower jaw a¹, in such a manner as to have a limited
longitudinal movement toward the front and rear of the machine.
To further keep it in its position, a guide lip is secured to said support M, and
overlaps the said feed bar near its front end. The forward and backward longitudinal
movement of this feed bar, and hence the feed, is effected by means of a forked arm f
fixed on the hollow shaft F, and engaging between its branches a laterally extending
stud or pin on the feed bar.
A rocking movement is given to the shaft F', by an excentric N, fixed on the
driving shaft B, and connected with a laterally extending arm n, fixed on the hollow
shaft F, at the heel end of the main frame, by a connecting rod n¹, provided at one
end with a strap n², surrounding the excentric N, and at the opposite end with a
clip n adapted to embrace and slide along the said arm n. The connecting rod n¹
is loosely connected with the clip n³, and the said clip is provided with a set screw n*,
for the purpose of fixing it to the arm n at any point desired, to give the shaft Fla
greater or lesser throw in its rocking movement, and hence the feed bar and feed, a
greater or lesser throw forward and backward, to increase or diminish the length of
-stitch.
It will be observed that by providing the arm n with a scale of any ordinary and

page_text: well-known form, the length of stitch may be varied with the greatest precision, and
with great facility.
The upward movement of the feed bar L is effected by means of a cam fixed on
the looper shaft F, in proximity to the end of the hollow shaft F¹, and preferably
immediately beneath the feed-bar L. The movement of the cam O, is so timed with
respect to the rocking of the shaft F', that it will engage and lift the feed-bar when
the latter is at or near the forward extremity of its throw, and will hold it elevated
until it nearly or quite reaches the rearward limit of its throw, when it again
recedes, and allows the feed-bar to drop into position to move forwardly out of contact
with the goods. By the above arrangement, the feed is effected with but a very
slight rocking movement of the shaft F, and hence very slight frictional wear.
In order to provide for the taking up of wear upon all parts where it is feasible,
the pressure foot bar P is formed triangular, and it is mounted in bearings p, one
section of which is made adjustable in a manner quite similar to that describod in
connection with the vertically reciprocating bar 6 herein before referred to at the
heel end of the frame, and in a manner quite similar to that in which the needle bar
is mounted.
As thus constructed, a person of ordinary skill may so manipulate the parts as to
take up wear, regulate the stitch, and adjust the feed, to suit all grades of goods
being sewn.
It is evident that slight changes might be resorted to in the formation and arrange-
ment of the several parts described, without departing from the spirit and scope of the
invention; hence, it is not intended to limit the invention strictly to the construction
herein set forth.
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 sewing machine, the combination with a reciprocating needle, of a vibrating
looper, having a forward and backward movement in a fixed plane, substantially as
Bet forth.
2. In a sewing machine, the combination with a reciprocating needle, of a vibrating
looper consisting of a hook thickened a short distance back from its point, forming an
oblique shoulder for opening the loop, substantially as set forth.
3. In a sewing machine, the combination with a reciprocating needle, of a rock-
shaft, a looper fixed thereon, a driving-shaft, and a vertically sliding bar connecting
the driving shaft and rock-shaft, through which a rocking motion is transmitted to
the rock shaft, substantially as set forth.
4. In a sewing machine, the combination with a reciprocating needle, a rock-shaft,
a looper on the rock shaft, a driving-shaft, and a cain on the driving-shaft, of a
vertically reciprocating bar provided at one end with a loop to embrace the cam, and
at the opposite end with an arm excentrically connected with the rock-shaft, sub-
stantially as set forth.
5. In a sewing machine, the combination with a rock-shaft for actuating the looper,
and a rock-shaft for actuating the feed, of a feed-bar having a longitudinal movement
and a swinging movement, a cam on the looper actuating shaft in engagement with
the feed bar, to give it its swinging movement, and an arm on the feed actuating
rock-shaft in engagement with the feed bar to give it a longitudinal movement, sub-
stantially as set forth.
6. In a sewing machine, two concentric rock-shafts, a driving shaft, connecting
devices between the driving shaft and rock shafts, a feed bar, and intermediate
mechanism between the rock-shafts and feed bar, for imparting to it its movement,
substantially as set forth.
7. In a sewing machine, the combination with the driving shaft, the feed bar, and a
rock-shaft, having a loose connection with the feed bar, of a laterally extending arm

page_text: fixed to the rock-shaft, and a rod connecting the driving shaft with the laterally
extending arm on the rock-shaft, substantially as set forth.
8. In a sewing machine, the combination with the driving shaft, the feed bar, and a
rock shaft having a loose connection with the feed bar, of a cam on the driving shaft,
a laterally extending arm fixed on the rock-shaft, a movable clip on the arm, and a
rod connecting the cam on the driving shaft, with the clip on the
arm, substantially
as set forth.
Dated this 22nd day of May 1890
NEWTON & SON,
Agents for the Applicant.