Year: 1886

page_text: I, ALEXANDER ANDERSON, Manager of the Singer Manufacturing Company's
Works Kilbowie, Dumbartonshire, do hereby declare the nature of this invention,
and in what manner the same is to be performed, (as communicated to me from
abroad by The Singer Manufacturing Company of New York in the United States
of America, Sewing machine Manufacturers,) to be particularly described and
ascertained in and by the following statement:-
This invention has for its object the provision in sewing machines of (1) a simple
and effective "four-motioned" feeding mechanism in which all of the movements
of the feed-bar are positive and in which the horizontal or feeding movements
thereof are easily regulated, and (2) a tension device, of simple construction,
capable of being operated so that the thread will be released at intervals from
most of the friction thereon but when thus released will still be held by a light
tension the latter being capable of being varied, to suit different kinds of work,
independently of the main tension.
For operating the feeding mechanism I provide a driving shaft with two
eccentrics so placed that their points of greatest throw are at an angle of
about 90° (or about at a right angle) to each other. To the frame of the machine
I pivot a rocker to which the feed-bar is jointed at its rear end, the forward end
of said bar being forked to embrace one of the said eccentrics which thus imparts
positive up and down movements to said bar.
To the feed bar, near its rear end, is pivotted a yoke which is forked or slotted
to embrace the other of the said eccentrics, the forward end of the said yoke being
jointed to a link which, in turn, is jointed to a feed-regulating lever near the free
end of the latter.
ر
The yoke and link form a toggle, and when the regulating lever is adjusted so
that the part of said lever to which the link is jointed is on a level, or nearly so,
with the pivot by which the yoke is jointed to the feed bar, said yoke, as the
Dis 077

page_text: eccentric rotates therein, will vibrate vertically on its pivot imparting little or no
horizontal movement to the feed bar. But when the free end of the regulating
lever is depressed to bring the point of connection of the link therewith more or
less below the point of connection of the yoke and feed bar, and thus shorten the
distance between these two points, the yoke, as it moves vertically, will also be
forced more or less horizontally and will thus impart horizontal movement to the
feed bar.
In the improved tension device I employ a pair of ordinary tension disks or
plates mounted on a pin having a shoulder between which and said disks is placed
a stiff spiral spring having but little tendency to expand, said disks being com-
pressed together and against said spring by a plate or lever having a tendency to
spring away from the disks but having an arm impinging against a flattened
portion or cam on a shaft. This flattened portion or cam holds the spring lever
against said disks at intervals, but allows said lever to move far enough at times
to clear the disks from the said stiff spiral spring. A light spiral spring, of
greater elasticity than the main tension spring and having coils of larger diameter
than the latter, is placed on the disk-supporting pin outside of or over the main
tension spring the said light tension spring being between one of the tension disks
and a regulating nut on the pin. This latter spring exerts a constant pressure on
the tension disks so that when the latter are released from the main tension spring
the thread passing between the disks will still be subjected to a slight pressure or
tension.
In the accompanying drawings Fig. 1 is a side elevation of a sewing machine
embodying my invention. Fig. 2 is a front end elevation and Fig.
a plan view
of the same. Fig. 4, is a detail plan view of the feeding mechanism, and Fig. 5 is
a detail sectional view thereof. Figure 6 is a sectional rear view of the bracket
arm of the machine showing the improved tension device and Fig. 7 is a detail
section showing the disks released from the main tension spring.
A indicates the frame of the machine in the lower part of which is journalled
the driving shaft B connected by a crank and pitman with the rear arm of a rock
shaft C pivotted by centre screws to the upper part of the frame. A. and having at
its forward end an arm connected by a link to a block secured to the needle bar D.
Thus as the driving shaft rotates, the needle bar will be reciprocated vertically, in
a well known manner. The driving shaft, as herein shown, carries at its forward
end a Wilcox and Gibbs hook L co-operating with the needle to form chain stitches.
The parts just above described. are merely shown incidentally with my invention
to illustrate its operation in connection with a complete machine.
The driving shaft is provided at its forward end with two eccentrics 10 and 11
the former being embraced by the slotted or forked free end of the feed bar 12
carrying the feed dog 13. The feed bar is jointed at 14 to a feed rocker 15 which
is pivotted on a pin or stud 16 attached to the machine frame A. Embracing the
eccentric 11 is a yoke 17 pivottally attached at its rear end to the feed bar 12 and
jointed at its forward end to a link 18, which in turn, is jointed at 19 to the feed
regulating lever 20 pivotted at 21 to the frame A. I prefer to attach to the work
plate P, a graduated segment 22 and to provide the regulating lever 20, the end of
which projects through a slot in said segment, with an index pin 23 so that the
operator may readily adjust the said lever to any desired position.
From the foregoing it will be apparent that as the driving shaft B is rotated the
eccentric 10 will impart positive up and down movements to the feed bar 12 and
to the feed-dog 13 carried thereby, while the eccentric 11 working in the yoke 17
will cause said yoke to move the feed bar connected therewith horizontally to feed
the work, the horizontal movements being positive in both directions and the
extent of these movements being governed by the position to which the regulating
lever may be adjusted, as above described.
The driving shaft B carries a fly and pulley wheel J baving a crank-pin j
connected by a pitman K with the rear arm e of a rock-shaft C, pivotted to or

page_text: journalled in the upper portion of the arm A, as shown particularly in figures 6
and 7. A pin F is screwed into the arm A and on said pin is a pair of ordinary
tension disks f. The pin F is provided with a shoulder between which and said
disks is a stiff coil spring G of slight elasticity or expansibility. Outside of the
spring G, between the tension disks and an adjusting nut H, is a light and very
elastic coil spring g, the pressure of which, against said disks, may be regulated by
said nut which runs on a threaded portion of the pin F.
Attached to the arm A by a screw a is a spring lever I which extends between
the disks fand the said arm, said lever having a tendency to move away from the
said disks but being held in contact therewith by an arm i bearing against a
flattened portion el on the rock-shaft C. Instead of said flattened portion of the
shaft a properly shaped cam may be employed. The lever I is steadied by a pin a¹
attached to the arm A, and the armi on said lever is preferably merely a tongue
struck out from the central upper portion of said lever to fork the latter so that it
may embrace the pin F.
When the machine is in operation the rocking movements of the shaft C, against
the flattened portion e¹ of which the arm i of the lever I presses, will impart a
slight vibrating movement to said lever. This operation of said lever will permit
the tension disks f to move away from the stiff coil spring G which has so little
elasticity that it will not expand sufficiently to follow the movements of said lever.
Thus the thread passing between the disks f will be relieved from so much tension
as is due to the pressure of said disks against said spring G. The light spring g
is, however, sufficiently elastic to follow the movements of the lever I and will
therefor hold the disks fagainst said lever at all times, and when the thread is
released from the main portion of the tension, due to the stiff spring G, it will be
subjected to a slight tension, due to the light spring g. When the parts are in the
position indicated by Fig. 7, the thread is released from the tension due to the
spring G, and is only subjected to the tension due to the spring g, but in Fig. 6
the parts are shown in the position they occupy when the full pressure is applied
to the thread.
The stress of the light tension spring g may be adjusted by means of the
regulating nut H without disturbing the spring G which latter is in its action,
independent of the light spring 9.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to
me, I declare that what I claim is:-
1. In a sewing machine the combination with a driving shaft, having two
eccentrics, of a feed bar carrying a feed dog and forked to embrace one of said
eccentrics, a rocker to which said bar is pivottally connected, a yoke jointed to said
feed bar and embracing the other of said eccentrics a regulating lever and a link
connecting the latter with said yoke, substantially as set forth.
2. In a sewing machine the combination with the work plate having a graduated
segment, the driving shaft having two eccentrics, the feed bar, feed dog, rocker,
yoke and link, of a regulating lever projecting through said segment and provided
with an index pin, substantially as set forth.
3. The combination with the tension disks of a supporting pin therefor having a
shoulder, a stiff spring between said shoulder and disks, a nut on said pin, a light
tension spring between said nut and disks, a lever against which the latter are
pressed by said springs and a shaft having a flattened portion or cam, for operating
Baid lever.
4. The combination with the tension disks, light and stiff springs, operating
independently of each other, a pin for supporting said disks, and an adjusting nut,
of a shaft having a flattened portion or cam and a lever forked to embrace said
pin and having an arm impinging against said flattened portion or cam on said
shaft.

page_text: 5. In an automatic or intermittent tension device, the combination with the
tension disks or plates and two independent springs separate from said disks or
plates and of different strength and elasticity, said springs both pressing in the
same direction against said disks or plates, of a movable lever or surface against
which said disks or plates are pressed by said springs, substantially as set forth.
Dated this Thirteenth day of April 1886.