IMPROVE- MENTS IN SEWING MACHINES
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by the said Arthur Greenwood at the
Office of the Commissioners of Patents on the 28th December 1883.
ARTHUR GREENWOOD Engineer of Leeds in the County of York "IMPROVE-
MENTS IN SEWING MACHINES"
This invention relates to a mode of driving the rotary shuttles of sewing machines
and giving them the requisite "dwell" without requiring a reciprocating motion to
bring them to their normal or starting position.
The invention refers more particularly to the construction of machine patented
by John Keats and bearing date March 17th 1877 N° 1085 in which vertical rods
are used as drivers of the rotary reciprocating shuttle such rods dipping into holes
made in the shuttle and being alternately raised to allow the needle thread loop, to
pass over the shuttle and under the drivers. These driving rods slide in guides
made for them in the vertical spindle to which rotary motion is imparted alternately
in opposite directions and the rods are alternately lifted clear of the shuttle by
means of a fixed annular cam in which run bowles projecting from or fitted to the
rods.
Now the object of this invention is to give to the driver an intermittant rotary
motion in one direction only, and so to time that motion that the requisite "dwell"
for the completion of the sewing operations may take place between each rotation
of the shuttle driver.
The manner in which I propose to give the shuttle its requisite motion while
sudden starting and stopping are avoided, is by the use of rotary cams, which
acting through bowles upon rock levers will transmit rotary motion to a crank pin
carried by the shuttle driver spindle. The levers admit of various modifications
without changing the principle of action. Thus for example I may use a pair of
levers fitted with bowles at one end and arranged on the lazytongs principle. To
the other ends of the levers I pivot links which connect with a crank pin carried
rD'Ը 11

page_text: by the driver spindle. By arranging a pair of suitably timed cams on the cam shaft
to act on the bowles of these levers I am enabled to impart one rotation to the
driver spindle for a small portion of a rotation of the cam shaft and thereby to
provide a "dwell" of sufficient duration to enable the stitch to be tightened, the
needle to descend take up a fresh loop and draw it through the work, and for the
divider to open out the loop and present it to the shuttle. Or in place of the lazy
tongs arrangement of levers I may fit a bowle on a pin which couples an arm
rocking on a fixed fulcrum with a rod for transmitting rotary motion through a
crank pin to the shuttle driver spindle. A cam on the cam shaft acts upon this
bowle and a second cam on the cam shaft acts upon a second bowle carried by an arm
of a bell crank lever pivotted on the framing of the machine. The other arm of
this bell crank is jointed to the connecting rod and thus the rod is caused to transmit
through the two cams the requisite intermittent rotary motion to the driver spindle.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Arthur Greenwood in the Patent Office on the 27th June 1884.
ARTHUR GREENWOOD Engineer of Leeds in the County of York "IMPROVE-
MENTS IN SEWING MACHINES"
This Invention relates to a mode of driving the rotary shuttles of sewing
machines and giving them the requisite "dwell" without requiring a reciprocating
motion to bring them to their normal or starting position.
The invention refers more particularly to the construction of machine patented
by John Keats and bearing date March seventeenth One thousand eight hundred
and seventy seven N° 1085, in which vertical rods are used as drivers of the rotary
reciprocating shuttle, such rods dipping into holes made in the shuttle, and being
alternately raised to allow the needle thread loop to pass over the shuttle and
under the drivers. These driving rods slide in guides made for them in the vertical
spindle, to which rotary motion is imparted alternately in opposite directions, and
the rods are alternately lifted clear of the shuttle by means of a fixed annular cam
in which run bowles projecting from, or fitted to the rods.
Now the object of this invention is to give to the shuttle driver an intermittent
rotary motion in one direction only, and so to time that motion that the requisite
"dwell" for the completion of the sewing operations may take place between each
rotation of the shuttle driver.
The manner in which I propose to give the shuttle its requisite motion, while
sudden stopping or starting are avoided, is illustrated in the accompanying
drawings, in which Fig: 1 Sheet I, is a plan view of the shuttle driving mechanism
applied to a Horn Sewing Machine, and Fig: 2 a side elevation of the upper
portion of the machine with the shuttle driving mechanism applied thereto.
I have also shewn at Fig: 3 Sheet II a modification of the shuttle driving
mechanism
In Sheet I. A is the nose of the horn on which the work is placed as indicated by
dotted lines in Fig: 2-B is the shuttle carried by a shuttle holder B₁ pendent
from the head of the machine, and set in rear of guides for the needle bar C and
presser bar D.-E is the vertical spindle which carries the drivers F. F. and is
mounted in the shuttle holder B¹. Keyed to the top of the spindle E is a disc E
fitted with a crank pin e. through which rotary motion is imparted to the spindle,
and through the drivers F. F. to the shuttle B.-H. H. is a pair of links which
serve to connect the crank pin e. with a pair of levers H₁ arranged on the lazy-
tongs principle, and mounted upon a fixed vertical axle H2. carried by a bracket
bolted to the framing of the machine. The free ends of these levers H¹ carry
bowls which respectively enter the cam grooves H³. H. cut in the upper and under
sides of the disc H keyed on the vertical cam shaft I. As this shaft is rotated, it
will, through the cam grooves, rock the levers H¹ on their fulcrum in such manner
as to impart through the links H and crank pin e. an intermittent rotary motion
to the spindle E, and thereby to cause the drivers to give to the rotary shuttle the
required movement for opening out the loop, entering it and passing through the
loop for the purpose of laying the locking thread therein The cut of the cam
grooves is such as to operate both rock levers in a way that will ensure their
moving only during about one third or less of the rotation of the cam shaft to
produce a revolution of the crank pin, and then to remain quiescent for the
remainder of the rotation of the cam shaft-By this means the shuttle, after
passing through the loop of the needle thread, will have a "dwell" of sufficient
duration to enable the other operations. viz: the tightening of the stitch, the feed
of the work, and the fetching up of the next loop through the work, to be carried
out.

page_text: The levers H, it will be seen by reference to Fig: 2, are cranked vertically so as
to enable their forward ends to work in the planes of their respective links.
The modification of shuttle driving mechanism for giving an intermittent rotary
motion to the shuttle I will now explain with reference to Fig: 3 Sheet II, which
is a diagram plan of the levers and cams in connection with the crank pin e. of the
shuttle driving spindle. Connected with this pin e. is a lever K which is pivotted
to a radius arm K¹ having a fixed fulcrum at L.-The pin which connects the
radius arm and lever together forms a stud axle for a bowle which enters a groove
formed in the upper side of a cam M on the cam shaft. K is a bell crank lever
rocking on a fixed fulcrum at N and connected by one arm through a link. K³ to
the lever K.-The other arm of the bell crank lever carries a bowle which enters a
groove formed in the under side of the cam M on the cam shaft. The cut of these
cams is such as to impart a revolution to the crank pine through the lever K
during some one third or less of a rotation of the cam shaft, and thus, as in the
arrangement first described, a dwell" of the shuttle driver is obtained while the
cam shaft is making the remaining portion of its rotation.
k
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.―
Imparting an intermittent rotary motion to shuttles of sewing machines with a
"dwell" for the completion of the sewing operations between each rotation of the
shuttle by the combined action of two rotary cams upon rock levers connected
with a crank pin of the shuttle driver spindle.
In witness whereof I the said Arthur Greenwood have hereunto set my hand
and seal this twenty fifth day of June in the year of our Lord One thousand eight
hundred and eighty four
ARTHUR GREENWOOD (L.S.)