IMPROVEMENTS IN LOOMS FOR WEAVING
Year: 1861

page_text: PROVISIONAL SPECIFICATION left by David Chalmers at the Office of
the Commissioners of Patents, with his Petition, on the 16th April
1861.
I, DAVID CHALMERS, of Glasgow, in the County of Lanark, North
Britain, Machinist, do hereby declare the nature of the said Invention for
IMPROVEMENTS IN LOOMS FOR WEAVING," to be as follows, that is to say:-
This Invention relates to the arrangement and construction of weaving
apparatus for actuating the shuttle boxes of drop-box looms, and is based
more or less upon an Invention of improvements in looms for which Letters
Patent were granted to the said David Chalmers and J. T. Swallow, and
dated the 17th of April, 1858, No. 837.
Under one modification of this Invention, the tappet shaft of the loom has
fitted to it an excentric, which is connected by means of a link to a vertical
rocking lever arranged at the back of the loom. This lever is centred on a
stud which passes through its lower extremity; the upper part of this lever is
forked, and on the ends are supporting pieces in which the journals of a short
horizontal bar are carried. This bar is of a square figure in its transverse
section, but with round or bead-like projections on the angles at the ends of
the bar. The central portion of this bar is perforated to correspond to the
number of shuttle boxes to be actuated. In front of the rocking lever, and
parallel thereto, is fitted a small rectangular frame which is bolted to the side
standard of the loom; within this frame there are arranged two or more
sliding pieces moving to and fro in a horizontal plane. The slides are of

page_text: a cruciform figure; the backward extremities form pins which enter the per-
forations in the square bar, when one of these is brought opposite to the end
of the slide. If, for example, two shuttle boxes are to be actuated alter-
nately, a hole is made through the bar opposite the extremity of one of the
slides, and at right angles to the first hole a second is formed corresponding to
the second slide. Above one end of the bar is arranged a catch lever, which
may be brought into gear with the beaded end of the bar at pleasure. With
this arrangement, when the tappet shaft gives motion to the rocking lever,
the catch causes the bar to turn upon its axis one-fourth of a revolution, and
it is held in this position while free from the catch by a spiral spring at the
side of the rocking lever. As the square bar is turned partially round it
presents a solid surface to the end of one slide, which is consequently pushed
forward, and one end of the vertical or T-part of the slide causes a rocking
frame, which is arranged parallel to the vertical parts of the slides, to turn
upon its axis. The spindle of the rocking frame carries at its outer extremity
a lever which is connected by means of a link to a weighted lever arranged
at the lower part of the loom framing. The front end of this lever is con-
nected to a vertical rod, the upper extremity of which is attached to the back
of the shuttle boxes, so that as the slides are moved to and fro, the upper or
lower end of the rocking frame is pushed forward, and this causes one or the
other of the shuttle boxes to be brought into the proper position for throwing
the shuttle through the shed.
The arrangement may be applied to any number of shuttle boxes which may
be actuated in any predetermined sequential order. In connection with the
take-up motion of the loom is arranged a wheel carrying round with it a pitch
chain so disposed; whenever there is a change in the pattern, a knob on the
chain lifts or depresses the lever, and that when the weft breaks, or the loom
is stopped from any other cause, the lever is actuated so as to keep the back-
ward end clear of the end of the square bar, and thus prevent its turning
upon its axis. This arrangement prevents any break occuring in the pattern;
obviates the necessity of the operator turning back the loom when a break
occurs, and so effects an important saving of time.