Improvements in Tension Controlling Devices for Button Hole Sewing and other Overseaming Machines.
Year: 1898

page_text: Date of Application, 29th Nov., 1898-Accepted, 4th Feb., 1899
VUMI LEIE
Improvements in Tension Controlling Devices for Button Hole
Sewing and other Overseaming Machines.
I, SAMUEL HICKOX WHEELER, of Fairfield, Fairfield County, Connecticut, United
States of America, Manufacturer, 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:-
The object of this invention is to provide sewing machines, constructed to
automatically stitch or overseam a given figure, with a tension controller, designed
to automatically vary the degree of tension to be applied to the upper or needle
thread during the stitching operation.
It is common in the construction of sewing machines to provide mechanism
capable of releasing the needle thread when the sewing mechanism is not in
operation. Such devices have been combined with sewing machines employing the
ordinary four motion feed, as well as with machines employing a cloth holding and
feeding clamp for overseaming or stitching predetermined designs or figures, such
as the overseaming of buttonholes, of eyelet holes, and the sewing on of buttons.
Generally considered, such tension releasing devices are made a part of the cloth
presser mechanism, as in the ordinary sewing machine; or a part of the cloth
holding and feeding clamp, as in automatic machines for overseaming or stitching
predetermined designs, so that the manual operation of the presser, or the clamp,
effects the operation of the tension release to release the needle thread.
In some instances, as when the tension release is employed in connection with
machines provided with stop motions, the tension release mechanism is operatively
connected with the stop motion, whereby the automatic operation of the latter effects
the automatic operation of the former. The employment of tension releases, such
as I have herein briefly referred to, is to avoid care on the part of the operator, so
the needle thread will not be broken when the machine is not in operation and the
material is manually moved under the needle. In such instances, the tension
release does not affect the form or quality of the stitch. My invention on the other
hand, has no relation to the convenience of the operator, but does not affect the
formation of the stitch.
My invention has for its purpose the automatic location of the lock, occasioned by
the interlocking of the needle thread with the under or bobbin thread, with relation
to the surface of the material operated upon, and to illustrate the operation of my
invention I select the overseaming of what is termed the square, barred end
buttonhole.
The design of overseaming here referred to comprises comparatively short over-
seam stitches (about one-sixteenth of an inch) for the overseaming of the two sides
of the buttonhole, and comparatively long overseam stitches (about three-sixteenths
of an inch) for the barring of the two ends of the buttonhole.
The overseam stitches common to the art are of two kinds, the purl and the whip
stitch: the former produced by giving to the bobbin thread a very light tension,
and to the needle thread a tension sufficient to draw the lock, occasioned by the
interlocking of the two threads, up through the material causing the lock to lie on

page_text: its upper surface; and the latter by giving to the needle thread a light tension, and
to the bobbin thread a tension sufficient to prevent the lock of the two threads being
drawn through the material. The purl stitch is most desired, and, of late, has
largely superseded the whip stitch, for the reason, that the effect produced by the
former is more like that produced by hand work. The excessive upper tension
necessary to the production of the purl stitch tends, when placing the comparatively
long bar stitches, to draw the material, especially such materials as are of soft and
fine texture, and owing to this defect it has been largely the practice to "machine"
overseam the two sides of the buttonhole, and afterwards to "hand bar" the two
ends.
My invention, as applied to the overseaming of button holes having square, barred
ends, renders practical the overseaming of the two sides of the buttonhole with the
purl design, and the barring of the two ends with the whip stitch design, by one
continuous automatic operation, while avoiding the drawn or pinched appearance of
the ends of the buttonhole, and the necessity of a second operation. It also provides,
in machines having a feed for a given design, for the autoinatic control of the needle
thread tension to automatically change the design of the stitch.
My invention is fully described in the following specification and is illustrated in
the accompanying drawings, in which,
Figure 1 is a back view in perspective of a portion of a buttonhole sewing machine
bringing into view the elements of construction necessary to better illustrate the
application of my invention thereto.
Figure 2 is a view in section on line e, a, Figure 1, to show in detail the construction
and operation of the needle thread tension, and
Figure 3 is a sectional detail on line z, z, to be referred to.
To the back slide frame way is securely attached the bracket a.
Pivotally attached to the bracket a, by the pivot screw a¹, is a rock lever all,
carrying at its rear end a roller 3, which, in the operation of the device, co-acts
with the tension controller at, carried by the rotating feed disc. To the front or
opposite end of the rock lever all is fulcrumed a screwthreaded sleeve 5, which
receives the male-threaded rod a", whereby adjustment may be made between said
sleeve and rod. The rod at its upper end, is suitably connected to the collar a
loose on the cutter bar rocker shaft X, the collar a having lugs as, a; the lug a³
acting to connect the collar to the rod a, and the lug acting to give motion
to a rock bar, pivotally secured in the overhanging arm by the screw b¹. The
hole in the rock bar 6 for the reception of the screw b¹, is considerably larger than
the body of the screw, and directly back of the rock lever b and encircling the body
of the screw is a cup washer 5, (see Figure 3) upon which the rock lever bar b
rocks when actuated to change the degree of tension normally given the needle
thread.
The rear end of the rock bar bis provided with two springs 61, 63, secured to the
rock bar by the screws 64, 65. The spring is positioned to actuate the
plunger (see Figure 2) which in turn moves the washer c¹ (held against the thread
carrying disc el to permit the latter to more freely revolve on the tension stud c*.
The parts shown in section in Figure 2, comprise the usual construction of needle
thread tension device as commonly employed in connection with the Wheeler &
Wilson automatic buttonhole sewing machine, and forms no part of my invention.
Any ordinary tension device provided with means, as the plunger c, to move the
friction disc c¹¹, so as to more or less vary the tension given the thread as it is fed
to the needle, would in combination with my improved construction effect the same
result, but that this particular construction of tension device may be thoroughly
understood, I will later on refer to it in detail.
The operation of my invention for the overseaming of a square, barred end
buttonhole is as follows:-The rotating feed disc carrying the tension controller (4,
makes two revolutions for a single cycle of feed movement of the cloth holding
clamp, and consequently for the overseaming and barring of a single buttonhole,
causing two engagements of the tension controller at, and the roller a³ for the

page_text: overseaming and barring of each buttonhole. The tension controller at is mounted
on the rotating feed disc, relative to the roller a³, so that they co-act to rock the
lever a, in the direction of the arrow, and so hold it during the barring of first
one and then the opposite end of the buttonhole. The movement of the rock
lever a, through the connections 5, a, and collar a7, transmits motion to the rock
lever b, carrying the spring 611, causing the latter to contact with and move the
plunger c against the bar c of the washer c', causing a slight movement of the
washer c¹ against the resiliency of the tension spring c³ which encircles the tension
stud c, securely held in the overhanging arm by the nut c. The stud ct is slotted
for about one-half of its length to permit of the movement of the bar c of the
spring washer c¹, and drilled out for the remainder of its length for the free
operation of the plunger c. The friction normally given the thread carrying
disc c¹¹ is controlled by the tension nut d forcing the thread carrying disc, through
the spring c³ and washor c', against a suitable seat formed in the overhanging arm
as at d. The thread carrying disc is constructed with a central hub " which at
its rear side bears against the arm as at d¹, the opposite side operating within the
cup shaped portion of the washer c¹. It is sometimes found advantageous to place
between the thread disc c¹¹ and its seat d', and between its opposite side d³, and
the washer c', a flexible washer (usually of felt).
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 buttonhole sewing machine, work moving mechanism, and needle-thread
tension mechanism, combined with a teusion controller, means interposed between
the tension controller and the work moving mechanism by which the tension con-
troller is actuated from said work moving mechanism, and connections between said
tension controller and needle thread tension mechanism whereby the degree of
tension given the needle-thread may be automatically varied by said controller
during the sewing operation and stitches of different character formed at the ends
and sides of the button-hole, substantially as described.
2. In a buttonhole sewing machine, a work feed mechanism including a rotating
feed disc, and a needle-thread tension mechanism, combined with a tension con-
troller and the needle-thread tension mechanism, whereby by the rotation of said
tension controller in unison with said feed disc the degree of tension given the
needle-thread may be automatically varied during the sewing operation, substan-
tially as described.
HASELTINE LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.