IMPROVEMENTS IN SEWING MACHINES
Year: 1868

page_text: PROVISIONAL SPECIFICATION left by William Joseph Curtis at
the Office of the Commissioners of Patents, with his Petition, on
the 9th October 1868.
I, WILLIAM JOSEPH CURTIS, of Neville Terrace, Holloway, in the
County of Middlesex, Civil Engineer, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN SEWING MACHINES," to be as
follows:-
My Invention of improvements in sewing machines has for its object
to produce a secure and fast stitch with only one thread. To this end
I employ a needle and thread in the manner usually adopted in sewing
machines, but underneath the work plate is mounted a double-acting
hook which is rotated alternately in opposite directions. When the
needle carrying the thread passes down through the work the hook is
rotated, say to the left, so as to cause its point to pass through the loop
in the thread, and by continuing its rotation, say for one complete turn,
the thread is twisted and a loop is formed, through which the. needle
on its second descent passes and liberates the thread from the hook, which.
will then be vibrated or turned in the opposite direction so as to cause
its other point to enter the second needle loop, which when laid hold

page_text: of by the second hook will be twisted to the right, and so on, the loop
in the thread being twisted alternately right and left so as to form a
fast and secure stitch.
A convenient mode of effecting the rotation of the hook is by causing
a nib to run to-and-fro along a diagonal slot or groove made in the shaft
which carries the double-acting hook, but other mechanical devices
for effecting the rotation of the hook alternately in opposite directions
may be employed.
The feed motion is effected by means of projecting nibs or feathers
on a reciprocating shaft being made to act upon the moveable feed
plate, which is further controlled by a spring, so that when the feathers
are withdrawn the spring will give a lateral motion to the plate, and
thus feed forward the work. This spring is fixed on the end of a rod,
which is capable of adjustment at the opposite end either to the right
or left on a gauge plate or other equivalent device, so that the spring
may be made to act in either direction. This machine may be actuated
either by a hand wheel, or winch, or by a treadle. If the machine is to
be actuated by a treadle I adapt two crank pins to the driving wheel,
one on each side of the wheel, but arranged to act at right angles to
each other like the cranks of a locomotive engine. These cranks are
connected by suitable rods or links to the vibrating levers of two treadle
shafts below. One of these shafts carrying one treadle is solid and
passes through the other shaft, which is a sleeve shaft and carries the
other treadle.
It is sometimes convenient to drive the hand machines by means of
a treadle, and to this end I make use of a removeable or temporary
treadle which is capable of being adapted to or detached from the
machine with facility. This temporary treadle consists simply of a
foundation plate on which is mounted the vibrating foot plate connected
at one end by a link or rod to the handle of the hand wheel. When
this temporary treadle is required it will only be necessary to place the
foundation plate in a proper position on the ground and then hook or
otherwise secure the upper end of the connecting rod over the handle
or crank pin of the hand wheel of the machine.