IMPROVEMENTS IN WEAVING
Year: 1855

page_text: PROVISIONAL SPECIFICATION left by George Lean and Robert Thomson
at the Office of the Commissioners of Patents, with their Petition, on
the 24th December 1855.
We, GEORGE LEAN, of Glasgow, in the County of Lanark, North Britain,
Manufacturer, and ROBERT THOMSON, of the same Place, Manager, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN WEAVING" to
be as follows, that is to say:-
This Invention relates to the application to power looms of self-acting
apparatus, for acting on the shed movements of the loom in such manner as to
produce plain weaving and twilling alternately, according to any predetermined
pattern. According to one-modification, of the said apparatus, the shaft corre-
sponding to the tappet shaft of ordinary looms is fitted with a tubular shaft or
boss, revolving loosely upon it, being driven at half its speed by means of any
convenient gearing, such, for example, as a pinion on the central shaft, in geor
with an intermediate spur wheel carried on a stud, this spur wheel being in
gear with or fast to a wheel in gear with a spur wheel on the tubular shaft. This
tubular shaft is fitted with four tappets, which, act on four levers for working
the heddles. The levers are formed with sliding bolts and catches in such a,
manner, that by shooting the bolts the levers may be coupled together in two
pairs. When the levers are so coupled, as the tappets are arranged so as
to strike one of each pair alternately, both levers of each pair act alter-
nately, and produce the heddle action required in plain weaving. When the
evers are uncoupled, the four act separately, and effect the twilling action.
The coupling bolts are thrown in or out by means of sliding spring guides,.
rranged so as to strike the bolt in any position of the lever, and to force it
home as soon as the positions of the two levers of a pair become coincident,
・

page_text: the bolt then flying home into its socket by the spring action. The shift of
the guides or bolt movers is effected by means of a small jacquard apparatus,
placed at any convenient part of the loom, the cards being cut according to
the pattern with a single row of holes, and acting by means of any suitable
intervening mechanism; or, instead of the jacquard apparatus, a disc or wheel
may be used, notches or projections being arranged upon it according to the
predetermined pattern, the notches or projections causing the motion of a
lever or other detail or details communicating with the guides as the wheel
turns round with the motion of the loom.
.
According to another modification of self-acting apparatus for effecting
the same result, the four levers for working the heddles, as herein-before
described, are used, but instead of the arrangements for coupling them
together for plain weaving, two additional levers, suitably connected with the
heddles, are employed. The tappets act on these levers by the intervention
of pulleys carried upon the levers, and when the plain weaving action is not
wanted, the action of the tappets of these two levers is prevented by shifting
the said pulleys in slots formed in the levers. This shift of the pulleys is
produced by the agency of sliding guides, which are themselves actuated in
the same manner as in the first modification of this Invention.
According to a third modification, arrangements are made for causing the
twill to run in either direction; for this purpose a frame is fitted to oscillato
on what is the tappet shaft in ordinary looms, & this frame carries two shafts,
each fitted with four tappets, to act on the levers or treadles below. These two
secondary shafts are placed on opposite sides of the main driving shaft, and
are driven at half the speed thereof by means of a spur wheel on each of them,
in gear with a pinion on the main tappet shaft. The tappets on one of these
secondary shafts are made smaller than those on the other, to compensate for
the difference in the distance from the centre of motion of the levers or treadles
at which they respectively act. The tappets are set so that one shaft works
the twill in one direction, the other working it in the opposite direction, one
or other of the shafts being brought into action by adjusting the frame. This
adjustment may be effected by means of the jacquard mechanism already
herein referred to, the cards being cut with a second row of holes for that
purpose. In combination with this last modification either of the herein-
before described modes of producing a plain weaving action at intervals may
be adopted.