IMPROVEMENTS IN SEWING MACHINES
Year: 1878

page_text: LETTERS PATENT to Alexander Anderson, Manager of the Singer Manu-
facturing Company's Works, Glasgow, North Britain, for the Invention of
"IMPROVEMENTS IN SEWING MACHINES."
Sealed the 15th April 1879, and dated the 17th October 1878.
PROVISIONAL SPECIFICATION left by the said Alexander Anderson at the
Office of the Commissioners of Patents on the 17th October 1878.
ALEXANDER ANDERSON, Manager of the Singer Manufacturing Company's Works,
Glasgow, North Britain. "IMPROVEMENTS IN SEWING MACHINES."
This Invention relates to improvements in that class of sewing machines which
has an arm for supporting the work, and is fitted with a circular reciprocating
shuttle. It is important that the arm which is to receive the work should be small,
and that the vertical needle which presents its loop to the locking shuttle thread
should work as near as possible to the end of the arm.
Generally the arms of such machines have proved too large, in consequence of
Thus
the working mechanism for driving the shuttle taking up too much space.
when a rack and pinion have been used for giving axial motion to the shuttle
driver, space was required within the hollow arm and beyond. the arm to allow for
the thrust of the rack, and when this simple mechanism was replaced by inter-
mediate spur gearing the advantage of a direct motion was lost.
I now propose to actuate the shuttle driver directly by mechanism which will
not protrude beyond the arm, and I am thus enabled to use an arm which will
permit of the needle working close to its extremity and of sewing close to the edge
of a boot sole.
One mode of effecting this object is to form the end of the reciprocating rack
with teeth hinged together in such a manner that they will slide within the
rounded end of the arm, as in a segment guide, and thus remain in gear with the
pinion which carries the shuttle driver.

page_text: A modification of this arrangement is to make an endless pitch chain, which
gearing into a driving pinion and into the pinion of the shuttle driver will impart
an axial motion to the latter. This driving pinion will be mounted on a shaft or
stud bearing, and may be driven by a segment rack formed on an oscillating lever
or from a crank pin working in a slotted cam, or in any other convenient manner.
As the chain has but a short traverse it may be formed with link rods at its
sides, the parts only that lap around the pinions requiring to be flexible. For
adjusting the time of the shuttle and maintaining the tension of the chain the link
rods may be fitted to the chain by adjusting screws. The driving motion may be
imparted to the chain by jointing to one of the link rods a rod connected to an
oscillating lever, having a reciprocating motion imparted to it.
Another means of maintaining the tension of the chain will be by mounting the
driving or tension pinion on a loose bracket, and by means of adjusting screws I
take up the slack caused by wear, and consequently always ensure a proper motion
to the shuttle.
Another mode of transmitting motion directly to the shuttle driver and within
the prescribed limits above indicated is to fit a crank arm on the spindle of the
shuttle driver, and to connect this arm with a similar crank arm on a reciprocating
driving shaft by means of a rocking link bar. This link bar I slot longitudinally
at about the middle of its length to receive a fixed fulcrum pin, over which it
slides, and upon which it rocks as on a moving fulcrum. The reciprocating driving
shaft may conveniently receive its motion from a segment rack forming part of a
rock lever. In this way I am enabled to work the shuttle driver within the con-
tracted space provided in the arm, and which admits of the needle working close to-
the end of the arm.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Anderson in the Great Seal Patent Office on the 17th
April 1879.
ALEXANDER ANDERSON, Manager of the Singer Manufacturing Company's Works,
Glasgow, North Britain. "IMPROVEMENTS IN SEWING MACHINES."
This Invention relates to improvements in that class of sewing machines which
has an arm in lieu of a table for supporting the work, and is fitted with a circular
reciprocating shuttle.
It is important that the arm which is to receive the work should be small, and
that the vertical needle which presents its loop to the locking shuttle thread should
work as near as possible to the end of the arm, in order to facilitate the manipula-
tion of the materials being sewn.
Generally the arms of such machines have proved too large for boot work, in
consequence of the working mechanism for driving the shuttle taking up too much
space.
Thus when a rack and pinion has been used for giving axial motion to the
shuttle driver space was required within the hollow arm and beyond the arm to
allow for the thrust of the rack, and when this simple mechanism was replaced by
intermediate spur gearing the advantage of a direct motion was lost. I now pro-
pose to actuate the shuttle driver directly by mechanism which will not protrude
beyond the arm, and I am thus enabled to use an arm which will permit of the
needle working close to its extremity and of sewing close to the edge of a boot
sole.
In the accompanying Drawings I have shewn in various views the manner of
effecting the above-mentioned object.
In Sheet I. of the Drawings Fig. 1 shews in inverted plan view and Fig. 2 in
vertical section so much of a sewing machine as will serve to explain one mode of
working the shuttle driver according to my Invention.
In these Figures A is the arm, in the extremity of which is a circular recess for
receiving the circular shuttle and the shuttle driver B. This shuttle driver consists
as usual of a disc with a driving stud or pin near the edge thereof for taking into a
recess in the shuttle. This shuttle driver is mounted on a spindle, which is fitted
at its lower end with a pinion C. In gear with this pinion is an endless chain D,
which extends back to a tension chain wheel E mounted in an adjustable bracket
bearing E¹. This chain D instead of being composed wholly of links is for con-
venience made up in part of two long link rods D¹, and to one of these is attached
two transverse pieces d, d, which form a guide for a sliding block d'. Projecting
from this sliding block is a pin, which enters a hole in the end of a rock lever F, by
which a reciprocating motion is imparted to the chain D.
This rock lever may receive its motion from a rotating cam similar to that here-
after referred to, or it may be driven in any other convenient manner. The bracket
arm which carries the tension pinion E is pivotted to the casting A at e, and it is
slotted transversely to receive a binding screw e', which passes through it and
enters a tapped hole in the casting A. By slackening this screw c¹ the tension
pulley E may be adjusted, and its position can then be secured by tightening up
the binding screw e¹..
Fig. 3 shews a slight modification of the mechanism just described for trans-
mitting motion to the shuttle driver. In this case the chain takes the form of
jointed rack teeth. Thus to the end of a reciprocating rack D¹ jointed teeth D aro
attached, the same being so constructed as to slide within a circular recess, in which
the pinion of the shuttle driver is situate, and thus remain in gear with the
pinion C of the shuttle driver.
Figures 4 and 5 shew in inverted plan view and section the rack bar D' con-
nected through the jointed links D with the shuttle driver without the intervention

page_text: of a pinion, the last link of the chain being jointed to a lug on a disc or collar
keyed to the axle of the shuttle driver. The action of this arrangement is precisely
similar to that shewn at Fig. 3. In Sheet II. Fig. 6 is a vertical section, and
Fig. 7 an inverted plan view of another mode of transmitting motion directly to
the shuttle driver, and within the prescribed limits above indicated. In this case
a crank plate C is fitted on the axle of the shuttle driver B, and a similar crank
plate on the axle of a reciprocating driving pinion E is connected with the crank
plate C by means of a rocking link bar D. This link bar is slotted longitudinally
at about the middle of its length to receive a fixed fulcrum pin d projecting from
the under side of the arm A. Over this pin the bar D slides, and upon it the bar
rocks as on a moving fulcrum. The driving pinion E receives its motion from a
segment rack F forming part of a rock lever F¹, which carries at its opposite end
a bowle that works in the groove of a rotating cam G on the cam shaft of the
sewing machine. In this way I am enabled as before to work the shuttle driver
within the contracted space provided in the arm A, and which admits of the needle
working close to the end of the arm.
Having now set forth the nature of my Invention of "Improvements in Sewing
Machines," and explained the manner of carrying the same into effect, I wish it to
be understood that under the above in part recited Letters Patent I claim, the
arrangement of mechanism above described with reference to Sheets I. and II. of
the Drawings, whereby the driver of circular shuttles is actuated directly within
the contracted space provided by the arm which supports the work.
In witness whereof, I, the said Alexander Anderson, have hereunto set my
hand and seal, the Sixteenth day of April, in the year of our Lord One
thousand eight hundred and seventy-nine.