The same object is attained in a split motion, patented by J. & R.
Shorrock, and Taylor, of Darwen. By means of eyeletted straps revolving
round a tightened warp thread, the doup or crossing threads drawn
through the eyelets make a very firm selvage when slit.
The picking motions require a few further remarks. For some goods,
especially fancies, the under pick is used. In this case the picking
stick is rather longer than the slay sword, and is fixed parallel to
it, projecting from the rocking shaft through the shuttle box and
picker. The loom, Plate VII., possesses the under-pick arrangement. It
is driven by means of the picking plate acting _downwards_ on a lever
centred at one end, whilst carrying at the other end a strap fixed to
the picking stick about four or five inches from the bottom end of it.
The scroll or side pick is a favourite one for velvet looms. The
picking plates are fixed on the _crank_-shaft, and consist simply of
a disc of metal carrying a lug so as to catch against a latch or lug
on a short inclined shaft at the loom side. This shaft at the bottom
end actuates by means of a strap and picking stick fixed as in the
under-pick loom. Obviously, the picking from each side of the loom must
be done alternately, and the plates at the loom side are arranged so
as to act only once in two revolutions of the crank-shaft. This motion
is obtained by means of a scroll plate on the crank-shaft carrying a
groove forming an inner and outer ring in the plate; in this works a
slide in the inner ring for one pick, then traversing the outer part of
the groove for the second pick. This slide regulates the latch on the
short shaft. When in the outer ring the latch is lowered so as to be
caught by the lug on the picking plate, but is out of the way when the
sliding piece is in the inner ring. Of course, when the slide is in the
inner part of the groove at the right-hand side of the loom, the slide
of the left-hand picking scroll is in the outer ring, so as to pick
alternately. This picking arrangement is very compact.
[Illustration: PLATE VI.--SHEDDING MOTIONS. _To face p. 79._]
SPEEDS.--AVERAGE SPEED OF NEW LOOMS.
Reed Space. Picks per Minute. If Double Cylinder
Plain. If Dobbied. If Drop Boxes. Jacquard.
32 inches 240 190 190 190
44 " 200 175 175 175
54 " 180 160 160 160
66 " 150 150 150 150
On goods with ordinary headings, the stoppages for changing shuttles,
piecing ends, etc., should not be more than one minute in twelve, or 8
per cent.
REED SPACE.
Public-domain text, read in full here on John Shaqi.
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