IMPROVEMENTS IN SEWING MACHINES
Year: 1863

page_text: LETTERS PATENT to George Haseltine, of the "International Patent
Office," No. 12, Southampton Buildings, Chancery Lane, in the County
of Middlesex, for the Invention of "IMPROVEMENTS IN SEWING MACHINES."
-A communication from abroad by Lebbeus Wisner Lathrop, of
Philadelphia, Pennsylvania, United States.
Sealed the 12th June 1863, and dated the 28th February 1863.
PROVISIONAL SPECIFICATION left by the said George Haseltine at the
Office of the Commissioners of Patents, with his Petition, on the 28th
February 1863.
I, GEORGE HASELTINE, of the "International Patent Office," No. 12,
Southampton Buildings, Chancery Lane, in the County of Middlesex, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN SEWING
MACHINES," (a communication from Lebbeus Wisner Lathrop, of Philadelphia,
Pennsylvania, United States,) to be as follows:-
The said improvements are situated below the bed plate of the machine, and
relate chiefly to a hollow grooved revolving hook used instead of a shuttle to

page_text: a flanged spool holder which works in the groove on the inside of the hook;
to the use of an expanding and contracting spindle for the lower spool; to a
spool guard which is constructed to prevent friction of the needle thread upon
the under thread and spool; to a hook for taking up and controlling the slack
of the needle thread as it passes from the point of the revolving hook, thereby
preventing its being tangled in the means and manner of regulating the tension
of the lower thread; to using the lower thread direct from the spool to an elastic
shuttle or knot stitch, and to the manner of combining and arranging the said
hook, spool holder, and guard. The revolving hook is fixed upon the end of
the shaft, which ruus lengthwise the machine. It is constructed hollow and
has a diagonal groove or slit cut to the full depth of its inner side. In the
hollow of the revolving hook is situated the flanged holder, the curved piece of
metal which forms the protection of the spool from the needle thread forming
at the same time the support of the expending and contracting spindle on which
the spool rotates. The hook for taking up and properly controlling the slack
of the needle thread is situated so as to catch the loop as it passes off the
point of the revolving hook, and receives the required motions from a cam on
the driving shaft acting through a lever and a connecting rod. The requisite
tension is obtained on the lower thread by carrying it back of the spool guard
through a slit cut therein for the purpose, and thence up under a tension spring
and back through a hole and over the spool, and then in and out of three holes
made in an arm of the spool guard. The spindle of the lower spool is con-
structed with a spiral spring in its centre, whereby it is adjustable to different
sized spools, and may be readily slipped in and out of position while it is thus
firmly secured. An ordinary spool is placed upon this expanding and con-
tracting spindle, the revolving hook, the spool guard, and the hook for control-
ling the slack of the needle thread being properly constructed and operated to
carry the loop of the needle thread around the same without difficulty. The
needle thread being carried through the fabric and a loop formed in the
manner, the point of the said revolving book enters the loop of the needle
thread, spreading it around and over the spool holder and guard until the
hook for controlling the slack seizes both threads of the loop and carries
them out of the way of the said hook, which has revolved to seize a new loop,
and as it passes around the second time draws up the slack thread, thereby
tightening the stitch. When the loop slips off the arm of the spool guard it
encircles the thread of the lower spool and draws it into the fabric in the usual
manner. Across the said slit in the revolving hook is placed a wire with a
sufficient space between it and the hook for a thread to pass, which prevents

page_text: the thread when carried over the spool from slipping back, and also gives it a
turn or twist as it carries it over the upper side of the spool guard, making a
half turn in the loop, causing the stitch to have a circle and a half of the upper
thread around the lower.
These improvements obviate the necessity of re-winding the under thread
from the common spool, which must be done in the bobbin and shuttle
machines.
By the above mode of forming the stitch a half knot is produced, which gives
great elasticity to the stitch, while its external appearance is the same as that
made by the use of the shuttle, for which reason it is called the elastic shuttle
or knot stitch.