IMPROVEMENTS IN LOOMS FOR WEAVING
Year: 1870

page_text: PROVISIONAL SPECIFICATION left by William Lawrence Mitchell at
the Office of the Commissioners of Patents, with his Petition, on the
23rd July 1870.
I, WILLIAM LAWRENCE MITCHELL, of Kirkcaldy, in the County of"
Fife, North Britain, do hereby declare the nature of the said Invention
of "IMPROVEMENTS IN LOOMS FOR WEAVING," to be as follows, that is to
say: :―
The first part of this Invention relates to the construction and
arrangement of the upper shell and the lay of looms, and it consists in
reference to the upper shell in forming it in the front side curved whilst
on the opposite side it is made flat. At about the central part of the
flat side a shallow groove is cut into which a narrow slip of timber is
placed having a curved form, and from the extremities of this said piece
of wood inclined holes are formed in the shell to receive an iron strap
or tension rod, the ends of which pass outwards beyond the termination.
of the shell proper. The ends of the strap or tension rod have screw.
threads formed on them and being provided with nuts these when.
screwed up tighten the strap or tension rod against the curved piece of
wood referred to and thereby stiffens the shell. In relation to the lay

page_text: -
this is stiffened under one arrangement by means of an iron plate formed
with upturned ends which are entered into the under side of the lay
beam, and is bolted by a series of bolts passing through holes formed in
the iron plate and the said beam. A curved metallic strap or tension bar
is also applied below the iron plate herein-before referred to, and it may
be constructed with upturned ends similar to those of the iron plate
itself, or its ends may have screw threads formed on them and passed
through inclined holes to the extremities of the lay beam. Under the
first arrangement, that is to say, when the tension bar is formed with
upturned ends it is strained by means of screwed bolts passing through
it and through the lay beam herein-before referred to, ferrules of the
requisite length being placed between the tension bar and the flat iron
plate. When constructed under the second arrangement, that is to say,
when the tension bar is prolonged and passed through the holes in the
end of the lay beam it is besides being strained by through bolts in the
manner herein last described further strained by nuts on the screwed
ends thereof, and the lay may be further stiffened by means of a tension
rod on the back thereof, as in the upper shell herein-before set forth.
The second part of this Invention relates to the uptake motion of
looms, and its object is to instantly relieve the palls from the teeth of
the ratchet wheels used in the said uptake motion by means of the foot
of the person attending the loom. It consists of a somewhat quadrant-
shaped plate carried on the stud or nave of the ratchet wheel and con-
nected to a lever which is again coupled to a treadle. The quadrant-
shaped plate has two wedge formed projections on its face which pass in
over the teeth of the ratchet. When it is necessary to relieve the palls
the attendant by treading on the treadle causes the quadrant by the
intervention of the lever referred to to move through an arc of a circle
so that the wedge-shaped projections are brought in under the several
palls which are thereby lifted out from the ratchet teeth.
The third part of this Invention relates to the driving of the lay and
the shuttle in such manner as to obtain two beats of the lay to each
shot of weft, that is to say, a beat for throwing up the weft in the
ordinary manner so as to form the cloth and a second or closing beat.
after the shed has been reversed. This is effected by driving the crank
shaft of the loom at twice the speed at present employed in any given
loom as hitherto constructed and by employing reducing gear for
diminishing the speed of the picking gear in the proportion of one shot

page_text: for each double beat of the lay in place of one shot to each single beat of
the lay as in ordinary weaving.
The fourth part of the Invention relates to the covering of the cloth
retaining roller or beam with india-rubber in place of emery powder,
glass, sand, or other pulverised substance or perforated or punched
metallic surfaces. The outer surface of the india-rubber is by preference
formed with small protuberances or teeth, or it may be grooved, or fluted,
or corrugated.