IMPROVEMENTS IN SEWING MACHINES
Year: 1881

page_text: LETTERS PATENT to Joseph Buchanan Robertson, of Lurgan, in the County
of Armagh, Ireland, for an Invention of "IMPROVEMENTS IN SEWING
MACHINES
"
PROVISIONAL SPECIFICATION left by the said Joseph Buchanan Robertson
at the Office of the Commissioners of Patents on the 9th March 1881.
JOSEPH BUCHANAN ROBERTSON, of Lurgan, in. the County of Armagh, Ireland.
"IMPROVEMENTS IN SEWING MACHINES."
My Invention relates to a construction of sewing machines in such a manner
that a variety of ornamental and other stitches can be produced by them. In
applying my Invention to a lock-stitch machine, I connect an arm carrying the
needle slide rigidly to an arm which carries the shuttle box, so that if the needle
be moved laterally or longitudinally out of its ordinary vertical path, the shuttle
box with the throat for the reception of the needle accompanies the needle in its
movements. I attach the arm carrying the needle slide to the fixed arm of the
machine which carries the presser foot by a flexible wire, strap, or spring, and I
connect the arm which carries the needle slide and shuttle box to two cams upon
the main shaft of the machine, or in some cases, according to the character of stitch
to be produced, upon a countershaft driven from the main shaft by gearing giving
it suitable speed; these cams serving, the one to give the needle arm an oscillating
movement in the longitudinal direction, and the other to give it an oscillating
movement in the lateral direction. The connection to either cam or to both cams
may when desired be dispensed with, and in that case the needle will receive one
or other or neither of the oscillating movements. By this arrangement I am
enabled to employ the sewing machine either for ordinary stitching, in which case
both cams are inoperative, or when one is made to operate the needle transversely
or longitudinally to the feed of the fabric, or when both are made to operate the
needle both transversely and longitudinally, zig-zag, French vein and other stitches
can be produced, their form depending on the extent and timeing of the oscillating
movements imparted to the needle. In cases where these movements are required
to be greater than can be conveniently allowed for by a spring joint, such as I
have mentioned, a ball and socket or other universal joint may be used for
connecting to the fixed arm the arm which carries the needle slide and shuttle box.
For chain stitching in which no shuttle is employed, I rigidly connect the bearing
of the hook or looper to the arm which carries the needle slide so that it always
follows the movements of the needle in the same manner as the shuttle box.

page_text: shuttle race B¹ partakes of the same movements, the position of the shuttle race
and the throat in it for the needle being thus always the same relatively to the
needle slide. The frame B is pivotted to the stationary head B³ of the machine by
a ball and socket joint b, so as to admit of the required longitudinal and lateral
movements. Instead of the ball and socket joint 6 the modified construction shewn
in Fig. 5, may be employed, the head B2 being in this case connected to an extension
upwards of the stationary head BS by an elastic wire b¹, having sufficient flexibility
to allow of the required movements in the horizontal plane. The frame B receives
these movements from two cams C¹ and C² on a countershaft C, driven by gearing
from the main shaft A. A lever arm C³ attached to B has a roller bearing against
the edge of the cam C', so that when the protuberance of the cam C¹ pushes the
roller upwards the line of the vertical path of the needle is directed towards the
main shaft, a spring c (Fig. 1) bearing against the frame B pushes it back.
Another arm C4 bearing against the shuttle race B¹ has a roller bearing against the
face of the cam C2, and a spring c¹ (Fig. 3) pushes against the opposite side of the
shuttle race. When the construction shewn in Fig. 5 is adopted the springs c
and c¹ may be dispensed with, the wire b¹ being of sufficient elasticity to push the
frame B in opposition to the action of the cams C and C². The extent of
movement given by the cam C¹ to the frame B can be made greater or less or
reduced to nothing by means of an adjusting stop screw c², the point of which
bears against the stationary frame of the machine. Also the movement given by
the cam C2 can be adjusted by shifting the roller on the arm C* nearer to or farther
from the face of the cam C2. When the two adjustments are so set that neither
of the cams C1, C2 moves the frame B, the machine so far as the needle movement
is affected works as an ordinary sewing machine, the needle always following the
same vertical path, and it is by giving it more or less of either or both the
horizontal movements determined by the cams C1, C2, and combining there with
variations of the feed that a great variety of stitches can be produced. Although
in the above description and in the Drawings to which it refers I have treated
the shuttle as being of the rectilineally reciprocating kind it is obvious that when
the shuttle moves in a path of another kind, as for example in a circular path, its
correspondence in position with the needle may be obtained as described by the
rigid connection of the shuttle race to the head carrying the needle slide. The
feed is effected by the movement of the presser foot D¹ which extends as an arm
down from the rocking shaft D. Another arm D² on this rocking shaft has a
roller bearing against a third cam C5 on the countershaft C, and by shifting this
roller nearer to or farther from the face of the cam C³ the extent of the feed is
varied as desired. For many kinds of ornamental stitching such as those of the
French vein kind, the countershaft C is geared to the main shaft A in the pro-
portion of 1 to 3. It is obvious that for such work the machine might be modified
by dispensing with the countershaft C, fixing its cams C1, C2, and C5 on the main
shaft A, and making the needle and shuttle cams A' and A³ of the three throw
kind, so as to give the needle and shuttle three strokes in each revolution. Again
by retaining the countershaft C with its cams and gearing it in various proportions
to the main shaft A, having on it two or three throw cams for working the needle
and shuttle, the character of the stitch may be in many ways varied. As examples
of some of the varieties of stitch that may thus be produced I shew in Figs. 6
and 7 combinations of six needle strokes vertically with lateral and longitudinal
movements of the needle and the fabric, each complete cycle of six stitches made in
the order of the numbers being produced by combining a set of three throw needle
and shuttle cams with suitable cams on the countershaft C driven at half the speed
of the main shaft. For making the stitch shewn in Fig. 6 a number of the
adjacent longitudinal threads of the fabric are first withdrawn, leaving only the
cross threads which are drawn together in bundles by the stitching as shewn. For
the stitch shown in Fig. 7 the fabric is left with all its threads complete. By cams
varying the extent and direction of the horizontal movements of the needle and the
extent of feed, and by variously timing the countershaft carrying those cams to

page_text: the main shaft, many other forms of stitching could obviously be produced. In
many cases the adjusting screws of the stop c² and the roller on C are so set that
the needle receives no horizontal travel at all; the stitching may then be varied by
varying the time, extent, and direction of the feed alone. In order to facilitate
such variations of feed I adopt an arrangement of feed cam and levers, such as is
shewn in elevation at Fig. 8 and end view at Fig. 9. The cam E has on its face
two cam paths, an outer path E¹, and an inner path E2, and the arm D³ extending
down from the rocking shaft D that gives the feed motion to the presser foot has
through it two setting screws e¹ and e², which may have rollers at their ends, the
one bearing against the face of the outer cam path E' and the other against the
face of the inner cam path E2, either or both being made by the adjustment of
the screws e', e², to take its bearing against the cam; the rocking shaft D and the
feed worked by it will receive movements corresponding with the configuration of
the two cam paths.
Having thus described the nature of my Invention, and in what manner the
same is to be performed, I claim as means of adapting a sewing machine for
producing ornamental and other varieties of stitching.
First. Connecting the head carrying the needle slide to the shuttle race by a
rigid frame, which being mounted by an elastic or universal joint receives lateral
and longitudinal movements determined by suitable cams, substantially as herein
described with reference to Figs. 1 to 5 inclusive of the accompanying Drawings.
Second. In a sewing machine adapted for ornamental stitching the combination
of a double pathed cam with double adjustable bearing studs or rollers on one feed
lever, substantially as herein described with reference to Figs. 8 and 9 of the
accompanying Drawings.
In witness whereof, I, the said Joseph Buchanan Robertson, have hereunto
set my hand and seal, this Twenty third day of July, in the year of our
Lord One thousand eight hundred and eighty one.
JOSEPH BUCHANAN ROBERTSON. (L.S.)