IMPROVEMENTS IN LOOMS FOR WEAVING ORNAMENTAL FABRICS, SUCH AS LENO AND MUSLIN CURTAINS
Year: 1867

page_text: PROVISIONAL SPECIFICATION left by Forrest Frew and James Speirs at
the Office of the Commissioners of Patents, with their Petition, on the
27th September 1867.
We, FORREST FREW and JAMES SPEIRS, both of Glasgow, in the County of
Lanark, North Britain, Manufacturers, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN LOOMS FOR WEAVING ORNAMENTAL FABRICS,
SUCH AS LENO AND MUSLIN CURTAINS," to be as follows, that is to say :—
This Invention relates to improvements designed to simplify and cheapen
the weaving, and more especially the weaving by power, of such ornamental
fabrics as leno or muslin curtains.
In carrying out these improvements a plain heddle leaf is arranged to act
on one half of the warps, and is placed behind the harness. The other half
of the warps, and of course alternating with those acted on by the back heddle
leaf, are acted on by the harness to produce the pattern in the ordinary way,
and may be termed the harness warps. In front of the harness there is placed
a gauze or "doup" heddle leaf arranged for producing a full gauze weaving
action. The warps acted on by the back heddles are passed through the
"doup" loops or heddles, whilst the barness warps are passed through the
spaces between the front heddle loops. There are four sheds in the cycle of
movements, and separate single weft shots are passed through each shed. The
jacquard apparatus is actuated by a cam movement, so as to operate at every
alternate shot only. After one harness shed the back heddles are raised for
the second shed, and with them the bar to which the "doup" loops of the

page_text: front heddles are attached, which action raises the heddle warp threads on,
say, the left-hand sides of the respective adjacent harness warp threads.
After the third shed, which is a harness shed, the front heddles are raised for
the fourth shed, and have the effect of raising the heddle warp threads on
the other or right-hand sides of the harness threads. The heddle warp
threads are passed over a separate bearer at the back of the loom, and by a
periodical cam movement this bearer is moved forwards so as to slacken that
portion of the warps sufficiently for the gauze action, at the same time that
the "doup" loops are made free to be drawn up by the raising of their bar,
and unequal strain on the warps is thereby prevented. In connection with
the improved arrangements herein-before described two weft protectors are
employed, one at each side of the loom, and the catch levers which act upon
them are actuated by pins suitably arranged on discs at the sides of the loom,
such discs being driven so as to turn once for each cycle of shedding
movements.
In weaving fabrics of the kind to which the present Invention relates two
wefts are used, a ground weft and a figuring weft, which are thrown alternately,
so that the two shuttles are thrown in succession both from one side and then
both from the other side. It follows thence that at successive beats up there
should be alternately a weft across each protector, and two wefts across one,
with none across the other. Pins may be arranged on the discs to cause each
protector to act at any desired stroke, but it is preferred to arrange them to
act only at those strokes at which there should be a single weft across each
protector. A single weft protector with its pinned actuating disc may be used
instead of the two, but its action will of course not be so complete as that of
the two.