IMPROVEMENTS IN DRIVING THE SHUTTLES OF SEWING MACHINES
Year: 1878

page_text: LETTERS PATENT to George Baldwin Woodruff, of Cheapside, in the City of
London, Engineer, for the Invention of "IMPROVEMENTS IN DRIVING THE
SHUTTLES OF SEWING MACHINES."
Scaled the 9th May 1879, and dated the 25th November 1878.
PROVISIONAL SPECIFICATION left by the said George Baldwin Woodruff
at the Office of the Commissioners of Patents on the 25th November 1878.
GEORGE BALDWIN WOODRUFF, of Cheapside, in the City of London, Engineer.
"IMPROVEMENTS IN DRIVING THE SHUTTLES OF SEWING MACHINES."
The object of this Invention is to provide a means for driving the circular
shuttles of that class of sewing machines which has an arm in place of a table to
support the work.
The shuttle driver of these machines is usually fitted with a pinion, which is
actuated by a driving rack acting directly on the pinion or indirectly through an
interposed pinion. When the rack acts directly on the shuttle driver pinion
provision has to be made in the end of the arm to allow it to protrude beyond the
arm, and this protruding of the rack creates difficulties in the manipulation of the
material being sewn, and it is to remove these difficulties that intermediate pinions
and other contrivances have been adopted.
These contrivances however inolved new difficulties which resulted in the
derangement of the timing and consequently of the true action of the shuttle.
I now propose to provide an arrangement of driving racks, which by preventing
back lash will so maintain the action of the shuttle when once properly adjusted,.
that the taking up of the loop of the needle thread by the shuttle will be insured.
On either side of the pinion of the shuttle driver I provide a rack; these racks
will extend rearwards to the main driving mechanism of the machine, and gear
with a pinion to which a reciprocating axial motion is imparted. These racks I so
adjust that they will alternately take into and drop out of gear with the teeth of
the pinion of the shuttle driver, and thus one rack will follow up the action of the
[Price 6d1

page_text: other, thereby driving the pinion alternately from opposite sides. By thus dividing
the driving motion the length of traverse of the racks is so reduced as to keep
them within the line of the arm.
In some cases I may find it desirable to connect the ends of these racks together
by flexible bands or links which will provide against the effects of wear, viz.,
backlash and an irregular motion of the shuttle.
To provide a lateral adjustment for the racks adjusting screws are tapped into
the sides of the arm, and caused to bear upon steel plates related into the arm and
forming bearing pieces over which the racks slide.
As a modification of this mode of driving circular shuttles I use one rack as a
driver, which besides gearing into and driving the pinion of the shuttle driver will
drive a second rack gearing into that pinion, and taking also into a second pinion
which receives motion from the first named driving rack.
By this arrangement I ensure that the shuttle driver when the shuttle is required
to take up the loop of the needle thread shall be driven directly from the main
driving rack in order to prevent any irregularity due to back lash, and it is the
complement only of the motion of the shuttle that is obtained from the second rack
and supplementary pinion.
In this arrangement, as in that first described, the racks will gear alternately
with the pinion of the shuttle driver.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Baldwin Woodruff in the Great Seal Patent Office on the
24th May 1879.
GEORGE BALDWIN WOODRUFF, of Cheapside, in the City of London, Engineer.
"IMPROVEMENTS IN DRIVING THE SHUTTLES OF SEWING MACHINES."
The object of this Invention is to provide a means for driving the circular
shuttles of that class of sewing machines which has an arm in place of a table to
support the work.
The shuttle driver of these machines is usually fitted with a pinion, which is
actuated by a driving rack acting directly on the pinion or indirectly through an
interposed pinion. When the rack acts directly on the shuttle driver pinion
provision has to be made in the end of the arm to allow it to protrude beyond the
arm, and this protruding of the rack creates difficulties in the manipulation of the
materials being sewn, and it is to remove these difficulties that intermediate pinions
and other contrivances have been adopted.
These contrivances however involved new difficulties which resulted in the
derangement of the timing and consequently of the true action of the shuttle.
I now propose to provide an arrangement of driving racks, which by preventing
back lash will so maintain the action of the shuttle when once properly adjusted
that the taking up of the loop of the needle thread by the shuttle will be insured.
In the accompanying Drawings my Invention is illustrated in several views:―
Fig. 1 (Sheet 1) shews in sectional elevation, and Fig. 2 in inverted plan view, so
much of a sewing machine with my Invention applied thereto as will explain one
form of my improved shuttle driving apparatus.
In these Figures A is the work supporting arm, the forward end of which is
recessed to receive the circular shuttle which is carried by the shuttle driver B.
This shuttle driver consists as usual of a horizontal disc fitted near its edge with a
driving pin for taking into a recess in the periphery of the shuttle. It is mounted
on a short spindle which carries a pinion C.
On either side of this pinion a rack D is provided, which racks extend rearwards
to the main driving mechanismn of the machine and gear with a pinion E, to which
a reciprocating axial motion is imparted by a segment rack carried by a vertical
rock lever F which is pivotted to and works in the hollow standard of the machine.
This rock lever carries at its upper end a bowle, which enters a groove in the
cam G on the main driving shaft. Thus the rotation of this shaft will through the
rock lever F and pinion E impart a reciprocating motion to the racks Ď, and
thereby actuate the shuttle driver. These racks are so adjusted that they will
alternately take into and drop out of gear with the teeth of the pinion C, and thus
one rack will follow up the action of the other, thereby driving the pinion alternately
from opposite sides. By thus dividing the driving motion the racks keep within
the line of the arm A..
Fig. 3 shews in inverted plan the two racks connected by a flexible band d,
in which case one rack only is needed to extend back to the pinion E or other
driver.
To provide a lateral adjustment for the racks adjusting screws a are tapped into
the sides of the arm A (see Fig. 2) and caused to bear upon steel plates a, rebated
into the arm and forming bearing pieces over which the racks D slide.
Fig. 4 shews in inverted plan view a further modification of the mode of driving
circular shuttles with racks. In this example one rack D is used as a driver,
which besides gearing into and driving the pinion C of the shuttle driver will
drive a second rack D₁ gearing into that pinion, and taking also into a second
pinion C which receives motion from the driving rack D.
This arrangement ensures that the shuttle driver when the shuttle is required
to take up the loop of the needle thread shall be driven directly from the main

page_text: driving rack in order to prevent any irregularity due to back lash, and it is the
complement only of the motion of the shuttle that is obtained from the second
rack D and supplementary pinion C'.
་
In this arrangement, as in the arrangement shewn at Figures 1 and 2, the racks
will gear alternately with the pinion of the shuttle driver.
Fig. 4 shews also a slight modification in the means for setting up the racks in
gear with the pinions. In this instance the adjusting screws a are provided with
flat heads, which bear against the back of the racks and serve the purpose of the
steel plates a' of Fig. 2. The screws are nicked at their points to permit of their
being adjusted from outside the arm A.
Sheet II. shews the same arrangement of shuttle driver as that described with
reference to Figures 1 and 2, Sheet I.; but in this instance the racks terminate at
the driving end of the machine in cranked slotted ends, and are connected together
by a rock lever D2 fitted at its extremities with pins which enter transverse slots in
the cranked ends of the racks. This coupling together of the racks is for the
purpose of imparting motion to both simultaneously, which motion is communi-
cated through a rock lever F connected by a link f to one of the racks. In all the
foregoing arrangements it will be seen that the shuttle driver is actuated in the
most important part of its movement (namely, that in which the shuttle enters
the loop of the needle thread) by the direct action of a rack, thus securing the
advantage of the direct acting rack without the disadvantage of its protruding
beyond the arm towards the end of its stroke. The driving mechanism working
within the arm and the liability of the shuttle working out of time being effectually
removed,
Having now set forth the nature of my Invention of "Improvements in Driving
the Shuttles of 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 arrangements of mechanism above described with reference to
the Drawings for actuating the driver of circular shuttles within the contracted
space provided by the arm which supports the work.
In witness whereof, I, the 'said George Baldwin Woodruff, have hereunto
set my hand and seal, the Twenty first day of May, in the year of our
Lord One thousand eight hundred and seventy nine.
GEO. B. WOODRUFF. (L.S.)