Improvements in Let-off Mechanism for Looms.
Year: 1890

page_text: The decision of the Chief Examiner, acting on behalf of the Comptroller, of the
15th day of September 1891, allowed, under Section 18 of the Patents, &c.
Act, 1883, an Amendment of this Specification.
[The Amendments are shown in erased and italic type.]
.Date of Application, 22nd Oct., 1890-Accepted, 20th Dec., 1890
COMPLETE SPECIFICATION (AMENDED).
[Communicated from abroad by JAMES MORTON, of Valley Falls, Providence, Rhode
Island, United States of America, Mechanic.]
Improvements in Let-off Mechanism for Looms.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent Agents,
45, Southampton Buildings, in the County of Middlesex, 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 and by the following statement :-
In the drawings accompanying this Specification
Figure 1, represents an end view with the invention applied thereto, portions of
the loom not necessary to such illustration being omitted.
Figure 2, detached sectional side view of the wheel G, illustrating the mechanism
to hold the wheel against rotation in one direction, but permit its rotation in the
opposite direction, and also the arrangement of the said wheel whereby it may be
thrown out of gear.
Figure 3, longitudinal central section on line -x of Figure 2.
Figure 4, longitudinal central section through the hub and spring chamber of the
lever b d.
Figure 5, front end view of the same showing the bracket.
This invention relates to an improvement in the mechanism employed in looms for
weaving, for the purpose of letting off the requisite amount of warp-threads as the
work progresses, the object of the invention being to automatically rotate the warp-
beam to the extent only required for the let-off, but at the same time to maintain a
substantially constant tension upon the warp, and the invention consists in the
mechanism for producing such automatic let-off and tension, as more fully herein-
after described and particularly pointed out in the claim.
The invention is applicable to various constructions of loom. That shown in the
illustration is one of common construction, only so much of the mechanism of
the loom being shown as is necessary to the description and understanding of the
invention.
A, represents the frame of the loom, B, the lay hung in the frame below, as
at C, and so as to vibrate backward and forward, in the usual manner, the mechanism
for such vibration not being illustrated. The warp beam is hung in the frame upon
an axis D, as usual, and to the end of the beam, or the shaft carrying the beam, a
gear E is fixed. In a suitable bearing on the frame, and below the gear E, a gear F
is arranged, here represented as outside the frame, the arbor of this gear F, carrying
a pinion which works into the gear E, the pinion not appearing in the illustration,
but so as to make connection between the wheel F and the wheel E, as usual in trains
of gearing.
Above the gear F, is a wheel G, loose upon its shaft H, the said shaft H, being
arranged upon or made as a part of an arm I, supported in a suitable-bearing in the

page_text: frame of the machine, and so that the said wheel G, may be raised or lowered, as
hereinafter described. The wheel G, carries a pinion J, which works into the wheel F,
as seen in Fig. 1, and so that if rotation be imparted to the wheel G, a corre-
sponding rotation will be imparted to the wheel F, through the pinion J, carried
by the said wheel G, and that rotation thence communicated to the gear E and the
warp-beam.
The wheel G, is prevented from rotation in one direction by means of pawls K K,
hung upon stationary studs L L, on the arm I, the said pawls operating upon internal
ratchet-teeth M, formed on the inside of the said wheel G, as seen in Figs. 2 and 3, so
that the rotation of the wheel G, is prevented in one direction, but free to rotate in
the opposite direction, and that opposite direction is in the direction indicated by the
arrow Fig. 1, which will produce the rotation of the warp-beam. N, represents the
tension bar arranged in suitable bearings and longitudinally over the warp-beam,
the bar extending from the axis 0, upward and forward, and so that the warps
running from the beam pass over said tension-bar, as seen in Fig. 1, a representing
the warps. At the end of the tension-bar or the shaft which carries it, a lever P
extends downward in rear of the wheel G. Forward of the wheel G a two-armed
lever b d is hung, upon an axis e, so as to vibrate in a plane parallel with the plane of
the wheel G. From the lower end of the lever P, and below behind the wheel G, a
rod connects the said lever P with the arm d of the lever b d, and below the
pivot on which the said lever b d, is hung as clearly seen in Fig. 1, and from
the upper arm of the said lever bd, connection is made to a band g, which
passes down partly around the wheel G, and is connected by its other end to the rod f.
The connection between the arm b and the band g, is made by means of a spring h,
said spring being under tension, tends to draw that end of the band g with a
yielding force toward the arm b; the pivot or fulcrum of the lever bd is made so as
to produce a yielding force in opposition to the spring-h. to exercise a yielding
resistance to the depression of the tension bar N by the warps. The construction for
this result is represented in Figs. 4 and 5; i, represents the hub of the lever bd,
which is made fast to the pivot or arbor e, which forms the axis on which the
lever bd vibrates.
The bearings for this arbor e, are formed as part of a bracket R, which is secured
to the frame; in this bracket is formed a spring-chamber S, concentric with the
arbor e, and through which the arbor passes, the inner end of the arbor taking a
bearing at the inner end of said chamber, the outer end of the chamber is closed by
Within the chamber a
a plug T, which forms the bearing for that end of the arbor e.
spiral spring U is arranged around the arbor, one end V, connected to the plug T, or
to some stationary point in the chamber, and the other end W, of the spring is con-
nected to the arbor, so that a rotation of the arbor in one direction will produce a
torsional strain upon the spring U, that is, will tend to "wind the spring," or in other
words, the spring will resist the turning of the lever in one direction, and that
resistance is opposed to the action of the spring-1, and the resistance of the said
spring U of the lever bd is substantially the same as that of the spring-h, and for the
purpose depression of the tension bar N by the warp as will hereafter appear.
Below the arbor or pivot of the lever b d, connection is made from the said lever to
the lay as here represented this is produced by a link k, hung by one end to the lay
as at 7, and extending therefrom rearward, it is constructed with a slot m, which works
upon a stud n on the arund of the said lever b d, and so that when the lay moves
forward, as in beating up, if the rear end of said slot m strikes encounters the stud n,
it will turn the lever d, accordingly, and the turning of the lever so produced will
correspondingly wind the spring U of the said lever-b-d.
As the two springs arranged as described, draw upon the opposite ends of the
band g, it follows that the band is held upon the periphery of the wheel I, under the
combined force of the two springs.
As has been said the coiled spring U offers an elastic resistance to the depression of the
tension bar N. Consequently when the bar N is subjected to extra warp tension it is
canted downwards drawing the lower end d of the lever bd forward so that at the next

page_text: forward stroke of the lay B the end of the slot in the link K encounters the stud n and
the lever b d is drawn back with the lay raising the tension bar against the tension of the
warp and sliding the belt round the periphery of the wheel G, the wheel being held by
the pawls KK. When the lever bd is released on the return stroke of the lay the
pressure of the warps depresses the tension bar N and pulls back the lower end of the
lever bd. Consequently the strap g rotates the wheel in the direction of the arrow
(Fig. 1) and lets off a certain amount of warp.
The arrangement of the pawls K, in connection with the wheel G, is such that when
the lay in a forward movement turns the lever bd, and consequently drawn draws upon
the band around the wheel G, the said pawls will resist or prevent the rotation of the said
wheel G, so that in such movement of the lever bd, no effect will be produced upon
or through the said wheel G.
When the lay moves forward, as before described, and turns the lever bd, the
operation will, because of the connection f, to the lever P, draw that lever P, forward,
and turn the tension bar upward against the warps; this tension bar acts like a cam
beneath the warps and so as to produce a strain thereon, thus tightening the warps
while the beam is beld to prevent let off under such increased tension.
When the lay retreats, the lever P returns under the reaction of the strain which
had been produced upon the warps and brings the lever 6 d, back to its normal
position, ready for engagement with the next beat of the lay.
The normal tension of the warps upon the tension bar is such that the lever bd,
will be turned so as to take the arm d to the rear between each beat to such an extent
that on the next beat of the lay the arm d, will be advanced to a certain extent, and
then as the lay returns, the reaction of the warps through the tension bar will return
the lever bd, and impart a certain amount of rotation to the wheel G, and thence to
the warp-beam as before described.
If the tension of the warps should be greater than the normal tension required, then
the depression of the tension bar and the second rear movement of the arm d, would
be greater than that occasioned by the normal. tension, the result of which would be
an increased rotation of the wheel G, by such rear movement of the arm d, and corre-
sponding increased let-off of warp; then on the next advance of the lay it will sooner
engage the lever b d, and bring the band back again to its normal position it
being understood that the tension bar is brought to the same position at each
stroke, that is, it arrives at its highest tensional power when the lay is in its extreme
forward position.
If, on the contrary, the tension of the warp should be too light, then the action
of the warps on the tension bar would be less, and the lever bd, would not be turned
so as to bring the arm d, so far to the rear as in the normal tension resulting in a less
rotation of the wheel to produce the let-off.
The two-springs-may be otherwise arranged, and the equilibrium-between-the
springs produced-necordingly.
The wheel G, is arranged upon the arm I, as before described, and that arm is made
fast to a shaft p, which is supported in a suitable bearing q, in the frame, and to the
other end of the shaft the lever r, is applied, terminating in a handle s, the axis of the
shaft p, being parallel with the axis of the shaft H, which carries the wheel G, and so
that by raising the lever r, the wheel G, will be raised to take its pinion J, out of
engagement with the wheel F, hence the wheel G, may be disconnected from the
wheel F, at any time, and such disconnection is desirable when a free rotation of the
warp-beam is required, as it frequently will be, as in the introduction of a new beam
to supply the place of a beam which had been exhausted.
. Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed as communicated to me by
my foreign correspondent I declare that what I claim is :-
First. The combination in a loom for weaving, of the lay and the warp-beam with the
wheel G, carrying a pinion said pinion being connected to the warp beam by a train
of gearing, mechanism between said wheel G and its pinion whereby the said wheel G,

page_text: will engage said pinion in the direction of let off, but prevent it from engagement
therewith when revolving in the opposite direction, a tension bar N, arranged to
swing against or from the warp-threads to apply to or remove tension-from said
threads, a lever P, extending from the said bar, a frictional band g, arranged around
said wheel and to run in frictional contact therewith, a second lever b-d, hung upon
an-axis so as to swing in substantially the same plane as the said lever-P, one arm d
of suid-lever connected to the suid lever P, one end of the said band connected to said
arm-d, and the other end of the band joined by a spring connection / to the
other-arm-b-of-the said lever, and a second spring opposed to said first-mentioned
spring-connection, and mechanism between the lay and the said lever-b-d,-whereby
the lay will engage the said lever-b-d-in-its- advance movement, substantially as
described.
First. The general arrangement and combination of parts comprising the improved
let of mechanism for looms substantially as described and shown.
Second. In a loom the combination of the lay and warp-beam of the wheel G,
carrying a pinion J, with mechanism between the said wheel G, and its pinion J, to
connect the two in one direction but to permit the wheel G, to run free in the
opposite direction, the tension bar N, the lever P, extending therefrom, the second
lever bd and connection f, between the said lever P, and the arm d of the said second
lever bd, a band passing partly around said wheel G, one end in connection with the
arm d, by means of the link fand the other end joined by a spring h, to the other
arm b, of the said second lever, the said second lever hung upon an arbor e, passing
through a chamber S, with a spring U around said arbor one end of said spring held
stationary in said chamber and the other end of said spring made fast to the arbor,
and mechanism between the lay and the said lever bd, whereby the said lay will
operate upon the said lever b d as the lay advances, all substantially as described.
Dated this 22nd day of October 1890.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.