Improvements connected with the Let-off Mechanism of Looms for Weaving.
Year: 1891

page_text: Date of Application, 2nd June, 1891
Complete Specification Left, 26th Feb., 1892-Accepted, 26th Mar.. 1892
PROVISIONAL SPECIFICATION.
Improvements connected with the Let-off Mechanism of Looms
for Weaving.
We, WILLIAM ROBERTSON, JAMES GUTHRIE ORCHAR, and THOMAS
ROBERTSON, of Wallace Foundry, Dundee, in the County of Forfar,, North
Britain, Engineers, do hereby declare the nature of this invention to be as
follows, that is to say :-
Our said invention relates to the let-off mechanism, or yarn-beam drag apparatus
of looms for weaving, and has for its object to provide improved means for
relieving the drag when the weaver requires to roll or turn the yarn beam back-
wards or forwards, an operation which in existing looms requires considerable
power especially with yarns for weaving heavy fabrics.
The drag is commonly applied to dragheads or friction pulleys fixed on the
yarn beam, by means of friction blocks on which the under sides of the pulleys.
bear, and ropes or chains drawn down upon the pulleys by levers on a shaft,
having also on it a lever extending to the front of the loom and acted on by a
weight or otherwise.
In carrying out the present invention, instead of having the friction blocks fixed
on stationary brackets, the brackets are made movable and are guided in any
convenient way, and the inner ends of the ropes or chains which pass over the
dragheads are hooked or fixed to the movable brackets. The end journals or
arbors of the yarn beam lie in the usual open bearings in lugs on the loom gables
or side frames; and when the strain is, in the ordinary way, taken off the levers
for the purpose of turning the beam backwards or forwards, the friction blocks
drop just sufficiently to be out of contact from the draghead. The beam then rests
by its end journals or arbors only, and can be turned with ease.
Dated this First day of June 1891.
EDMUND HUNT,
Applicants Agent.
COMPLETE SPECIFICATION.
Improvements connected with the Let-off Mechanism of Looms
for Weaving.
We, WILLIAM ROBERTSON, JAMES GUTHRIE ORCHAR, and THOMAS:
ROBERTSON, of Wallace Foundry, Dundee, in the County of Forfar, North
Britain, Engineers, do hereby declare the nature of this invention and, in what
manner the same is to be performed, to be particularly described and ascertained in
und by the following statement, that is to say :---
Our said invention relates to the let-off' mechanism, or yarn beam drag apparatus
of looms for weaving and has for its object to provide improved means for
relieving the drag when the weaver requires to roll or turn the yarn beam back-
wards or forwards, an operation which in existing looms requires considerable
power especially with yarns for weaving heavy fabrics.
The drag is commonly applied to drag head or friction pulleys fixed on the yarn
beam, by means of friction blocks on which the undersides of the pulleys bear, and
ropes or chains drawn down upon the pulleys by levers on a shaft, having also on
it a lever extending to the front of the loom and acted on by a weight or
otherwise.
In carrying out the present invention, the brackets carrying the friction blocks.

page_text: are made movable and are guided in any convenient way, and the inner ends of the
ropes or chains which pass over the drag heads are hooked or fixed to the movable
brackets. When the strain is taken off the levers the friction blocks drop just
sufficiently to be out of contact from the drag head and the beam then rests by its
end journals or arbors only and can be turned with ease.
And in order that our said invention and the manner of performing the same
may be properly understood we hereunto append a sheet of explanatory drawings
to be hereinafter referred to and showing by way of example, two simple and
convenient modifications of our improvements.
Figure, 1, on the accompanying sheet of drawings is a partial side elevation of a
loom, and Figure, 2, a partial end elevation showing one modification.
Figure, 3, is a sectional side elevation showing a second modification.
In these drawings the same reference letters are used to mark the same or like
parts wherever they are repeated.
In the modification shown in Figures, 1, and 2, of the accompanying drawings
cach of the drag heads or friction pulleys, A, fixed on the yarn beam, B, is acted
on by a friction block, C, fixed on a movable bracket, D, connected by a stud, E,
to the loom gable or side frame, F, the stud entering a slot in the bracket. The
outer part of the bracket, D, is made with a projection, G, which rests on the
upper side of a cam, H, (shown by dotted lines in Figure, 1) on a rocking shaft, J,
extending across the back of the loom. The inner end of a chain, K, which passes
over the friction pulley, A, is attached to a hook, 1, on the movable bracket, D,
its outer end being attached to an adjustable link, M, connected to a hooked
lever, N, made in a piece with the cam, H. The end journals or arbors, P, of the
beam lie in the usual open bearings in lugs, Q, on the side frames, F. A lever, R,
extends from the rocking shaft, J, to the front of the loom where it is connected
through a chain, S, to a quadrant, T, having a handle, V, fixed to it by moving
which the lever, R, can be raised or lowered. When the lever, R, is raised to
put on the strain the handle, V, is engaged in a notch in a curved bar, the strain
ing relieved on taking the handle out of the notch. Each chain, K, is then
loosened and each movable bracket, D, drops just sufficiently to move the friction
block, C, out of contact from the pulley, A. The beam, B, then rests by its end
journals or arbors, P, only, and can be turned backwards or forwards with case by
means of any suitable known mechanism that shown in the drawings consisting of a
bevil wheel, W, on the end of one journal, P', gearing with a pinion, X, on a
shaft, Y, extending to the front of the loom where is provided with a hand-
wheel, Z, for turning it by.
In the modification shown in Figure, 3, each inovable bracket, D, rests on the
boss of the hooked lever, N, the drag being applied or released, in this modification,
simply through the action of this lever on the chain K.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
In the let-off mechanism of looms for weaving, connecting the friction ropes or
chains which act on the drag heads or pulleys of the yarn beam to brackets
carrying friction blocks which act on the undersides of the drag heads or pulleys,
the said brackets being movable and adapted to recede from contact on the drag
strain being relieved substantially in the manner and for the purposes hereinbefore
described.
Dated this Twenty-fifth day of February 1892.
EDMUND HUNT,
Applicants' Agent.