IMPROVEMENTS IN LOCK-STITCH SEWING MACHINES
Year: 1875

page_text: PROVISIONAL SPECIFICATION left by James Henry Smith at the
Office of the Commissioners of Patents, with his Petition, on the
13th January 1875.
I, JAMES HENRY SMITH, of Albion Works, Landsdowne Road,
London Fields, in the County of Middlesex, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN LOCK-STITCH SEWING
MACHINES," to be as follows:-
1
This Invention relates to lock-stitch sewing machines in which a
shuttle is employed for the under thread, and it consists in improved
construction and arrangements for the presser foot, the take-up of
the needle thread, the shuttle and its carriage, the feed and loop
catch.
For the presser foot I employ a flat blade spring instead of the helical
spring ordinarily used. I fix one end of this spring on a bracket pro-
jecting from the side of the presser guide, and make the other end of
the spring bear in a slot on the top of the presser spindle or on a stud
projecting from its side,

page_text: My improved take-up consists of a lever with an eye through which
the thread is passed, which lever is worked by a cam on the revolving
shaft that works the needle. This cam can be set where required on
the shaft, and shaped so as to time the take-up action suitably to the
stroko of the shuttle.
In my improved shuttle I fit a blade lever with a hook projecting
through the upper side of the shuttle. The shuttle thread is passed
through an eye in this hook, and the lever is pressed by a spring so as
to draw the hook towards the front of the shuttle, and to yield back-
wards when the strain comes upon the shuttle thread, thus serving to 1
take up the slack of the said thread.
I also mount upon the shuttle carriage a bell-crank lever, one arm of
which usually lies under the shuttle and the other arm projects upwards
at the back thereof, and terminates in a nose bent over the shuttle.
This nose serves to keep the shuttle down in its carriage and also to 1
retard the passage of the loop of the needle thread over the shuttle, so
that when the machine is employed to work chain stitch, by suppressing
the shuttle thread, the loop formed by the shuttle is held until the
looping hook receives it for the succeeding stroke of the needle through
it. This lever has an arm projecting under the shuttle carriage, which 2
can be raised by the finger of the operator so as to move away the bent
and from above the shuttle and at the same time to lift the shuttle out
of its carriage when it is desired to take out the shuttle, thus avoiding
the use of any separate instrument for that purpose.
My improved feed is worked by two levers at right angles to each a
other, or nearly so, one vertical, worked by a crank on the revolving
shaft which works the shuttle, and the other lover horizontal, to which
the former lever is jointed. By means of these levers the feed receives
from the one crank the fourfold motion necessary for advancing the
fabric.
The fulcrum of the vertical lever is on a lever that can be moved
by hand along a slot in the vertical lever so as to give the feed more or
less stroke, as may be desired.
For catching the loop of the needle thread before the shuttle enters it,
I provide a hook worked by a com on the shuttle shaft an athonwion

page_text: which hook is timed so as enter the bulge formed by the partial ascent
of the needle, into which it is immediately followed by the shuttle. By
the use of this hook-I am enabled to work the needle without pause in
its
up stroke by means of a simple crank, cam, or eccentric.