IMPROVEMENTS IN SEWING MACHINES
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by Thomas Warr, William Brown, and
Alexander Russell at the Office of the Commissioners of Patents on the 7th
March 1877.
THOMAS WARR, of Lec, in the County of Kent, WILLIAM BROWN, of Bermondsey,
in the County of Surrey, and ALEXANDER RUSSELL, of Glasgow, North Britain.
"IMPROVEMENTS IN SEWING MACHINES."
Our Invention has for its object causing a periodically recurring rest or pause
during the progress of the sewing in the feeding or in the action of the feeding
mechanism of a single-thread sewing machine, during which rest or pause the needle
may re-enter the material sown at the exact place from which it has just been
raised, thus allowing two or more stitches to be made in one place at such intervals
as may be arranged, whereby increased strength and firmness in the seam are
obtained, and the liability to give out or rip and part, to which seams as usually
sewn are subject, is considerably diminished. A rest or pause may be arranged for,
according to requirements, that is to say, a rest or pause may be caused to take
place once in one inch, or more or less, of sewing, thus forming at given points a
stop or additional lock in the seam, ensuring a greater degree of resistance to any
sudden or undue strain upon the seam.
This Invention is especially adapted to sewing machines used in making costumes
or any garment or article in which elasticity and strength of seam combined are
required.
The rest or pause may be effected in various ways.
According to one mode of carrying out our Invention we employ a ratchet wheel
provided with teeth of uniform size and pitch upon a portion of its periphery, and
at intervals, as desired, with a tooth of prolonged and increased dimensions, or one
only of such prolonged teeth may be provided in the entire toothed periphery of the
wheel. The ratchet wheel is placed upon the machine in such a position as to
receive its rotation by the action of a pawl upon the end of the feed block, or the
end of a feed block made in the form of a pawl, or a pawl placed in any such
position as to receive motion from the machine, and act upon the said ratchet wheel
in such a way as to ensure a rest or pause at desired intervals in the action of the
feed mechanism, thereby attaining the desired object. The feed block or pawl in
its return motion comes into contact with the said uniform teeth of the ratchet
Duino 91

page_text: wheel, and by its upward movement gives rotary motion to the wheel until in the
revolution a prolonged and enlarged tooth is brought opposite the feed block or
pawl. A resistance and temporary stop to the returning motion of the feed block
then takes place, to be again overcome by the repeated and entire action of the
feeding mechanism, when the ratchet wheel is again set in motion by the action of the
pawl upon its teeth, the stops or pauses occurring at the intervals as arranged during
the working of the machine.
According to another mode of carrying out our Invention we employ a sliding
pin so arranged in relation to the feed block that when impelled forwards at regular
intervals by any suitable apparatus operated automatically from the machine it
shall be brought within the range of the feed block, so as to arrest its back motion,
a spring being employed to return the pin to its normal position clear of the feed
block as soon as the operating pressure is removed, and to retain it in such position
until it is again impelled forwards by the said apparatus, and so on, repeating the
operations continuously.
The apparatus employed for actuating the pin may consist of a rod operated by
an eccentric crank or crank disc, which is carried on a shaft driven by bevil gearing
or otherwise from the main shaft of the machine; or we may substitute for the
eccentric crank or crank disc or cam operated by a worm and worm wheel from the
said shaft, and either arranged to positively actuate the pin at the requisite intervals,
the said pin being in that case withdrawn by a spring in the manner before
mentioned, or the spring may be so arranged as to impel forwards or actuate the
pin, whilst the cam is employed for releasing the latter.
*The apparatus may be so arranged as to be capable of being thrown into and out
of gear or action, as required, by the aid of slides and levers or other suitable
connections.