AN IMPROVED LET-OFF MOTION FOR LOOMS
Year: 1863

page_text: States of America, for the Invention of "AN IMPROVED LET-OFF MOTION
FOR LOOMS." A communication from Silas Shepard, residing at Taunton,
in the County of Bristol, in the State of Massachusetts, one of the United
States of America.
Sealed the 31st March 1864, and dated the 17th October 1863.
PROVISIONAL SPECIFICATION left by the said Lewis Reese Chesbrough
at the Office of the Commissioners of Patents, with his Petition, on
the 17th October 1863.
I, LEWIS REESE CHESBROUGH, of the City of Brooklyn, in the County of
Kings, in the State of New York, one of the United States of America, do
hereby declare the nature of the said Invention for "AN IMPROVED LET-OFF
MOTION FOR LOOMS," a communication, to be as follows:-
Said Invention consists, first, in interposing a rest or guide between a
vibrating whip roll, or any vibratory equivalent therefor, and the warp yarn
beam, in such a manner that the yarn shall pass over said rest or guide and
keep the angle formed in the yarn by the whip roll between the rest and the
lay unchanged, except by the vibrations of the whip roll, and unaffected by
changes of the yarn from a full to an empty beam; the interposition of the
rest or guide being such that the general direction of the stress from the yarn
caused by tension thereupon and tending to straighten the yarn between the

page_text: lay and the rest is substantially at right angles to a line drawn from the
acting surface of the whip roll and through the centre on which it vibrates.
And it may bere be said that the shaft on which the whip roll vibrates and to
which it is connected by rocker arms, forms a good rest or guide for the yarn
as it passes from the yarn beam to the whip roll and thence to the lay and
breast beam beyond.
And said Invention also consists in the connection of a vibrating whip roll
or its equivalent, and a weight with an escapement mechanism which, operated
by the tension on the yarn and the stroke of the lay, lets off automatically and
intermittently from the yarn beam the exact amount of warp yarn required by
the weaving operation, and maintains the tension uniform on the yarn from a
full to an empty beam.
This Invention is applicable to the well known forms of looms having a
cloth beam and a warp yarn beam and other parts well known to weavers
and others. On one end of the yarn beam there is a gear wheel and on one
end of a short shaft inside the loom frame there is a pinion, while on the other
end of the said shaft outside of the frame there is an escapement wheel, and
this short shaft is best located beneath the yarn beam. Above this beam
and extending across the loom framé is a shaft which is used for a rest or
guide for the warp yarn as it comes from the warp beam; this shaft turns in
bearings in the frame and there are upon it, one at each end, two rocker
arms pointing towards the breast beam and bearing the whip roll. On one
end of the rest shaft is a lever fixed thereupon near its centre, from one pro-
jecting end of which hangs a weight the tendency of which is to elevate the
whip roll, while from the other end of said lever there depends a rod so
arranged that its free end may strike in its descent one end of a pallet or
detent which operates in connection with the escapement. The yarn passes
up from the yarn beam over the rest and from thence to the take-up, which in
its normal position is maintained sufficiently high above a line drawn from the
rest to the breast beam to form an angle in the line of the warp yarn so that
the tension produced by the take-up and the blows of the lay, by straightening
the line of yarn, depresses the take-up roll, elevates the weight, and depresses
the pendent rod so as to let the escapement turn one tooth under the vibration
of the pallett caused by depression of the pendent rod. The yarn beam is
thus allowed to turn and let off, and the weight falls and preserves the tension
on the yarn.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Lewis Reese Chesbrough in the Great Seal Patent Office
on the 1st April 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, LEWIS REESE
CHESBROUGH, of the City of Brooklyn, in the County of Kings, in the State of
New York, one of the United States of America, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventeenth day of October, in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-seventh year of
Her reign, did, for Herself, Her beirs and successors, give and grant unto
me, the said Lewis Reese Chesbrough, Her special licence that I, the said
Lewis Reese Chesbrough, my executors, administrators, and assigns, or
such others as I, the said Lewis Reese Chesbrough, my executors, adminis-
trators, and assigns, should at any time agree with, and no others, from
time to time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and Isle of Man,
an Invention for "AN IMPROVED LET-OFF MOTION POR LOOMS,' a communica-
tion) upon the condition (amongst others) that I, the said Lewis Reese
Chesbrough, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately after the
date of the said Letters Patent.
NOW KNOW YE, that I, the said Lewis Reese Chesbrough, do hereby
declare the nature of the said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement:-
The nature of the said Invention for an improved "let-off" motion for looms
is as follows:-it consists, first, in interposing a rest or guide between a vibra-
ting whip roll, or any vibratory equivalent therefor, and the warp yarn beam
in such a manner that the yarn shall pass over said rest or guide so as to keep
the angle formed by said vibrating whip roll or its equivalent between the said
rest or guide and the lay unchanged, except by the vibrations of said vibrating
whip roll or its equivalent and unaffected by changes of the diameter of the
coil or roll of yarn from a full to an empty yarn beain; the manner of the
interposition of the rest or guide being such that the general direction of the

page_text: stress from the yarn caused by tension thereupon, and tending to straighten
the line of the yarn formed between the lay and the rest, is substantially at
right angles to a line drawn from the acting surface of the whip roll or its
equivalent through the centre on which it vibrates. In such a position the
whip roll is more easily depressed, and more sensitive to the depressing
tendancy caused by the effort of the tension to straighten the warp yarn than
it is when made to occupy any other position relative to the rest and lay.
And it may here be said that a shaft acting as a center on which the whip
roll vibrates and to which it is connected by rocker arms forms perhaps the
best device for a guide or rest for the yarn as it passes from its beam toward
the lay breast beam & take-up roll.
.
And said Invention also consists in the connection of a vibrating whip roll,
or its equivalent, and a weight which operates to oppose depression of the whip
roll with an escapement mechanism so as to operate the escapement auto-
matically through the tension upon the yarn and the beating of the lay by the
depression and elevation of the whip roll, and cause the beam to turn and let
off yarn therefrom intermittently in quantities exactly proportioned to the
requirements of the weaving, while the tension on the yarn is at all times
maintained uniform, no matter whether the beam is full or empty.
Said Invention is applicable to the ordinary well known forms of looms,
and to enable others skilled in the art to practice it, I will now proceed to
describe its embodyment in detail, referring to the Drawings which accompany
and form part of this Specification, and to the characters of reference there-
upon marked.
Figure 1 of the Drawings is a side view of enough of a loom to embody
and illustrate the Invention herein described; Figure 2 is a front view of
the same.
'
A represents the frame of a loom or a portion thereof, to which my Inven-
tion is applied; B, the yarn or warp beam; C, the vibrating leaf or whip roll,
which may be arranged either as a roll turning in bearings projecting from a
rocker guide shaft D, or as a leaf or arm projecting from said shaft D, as
shown in the Drawings. The shaft D, which is the rest or guide before men-
tioned, over which the yarn passes from the yarn beam on its passage to the
whip roll or tension leaf, is made so that it and the parts dependant upon it
can rock or vibrate on or from the centre of shaft D. The warp yarn is
denoted by the line x, x, in the Drawings. The shaft D is placed in any
convenient position over the warp yarn beam, that which is shown being
preferred, and the vibrating tension leaf is located between said shaft and
breast beam at a suitable degree of elevation above a line drawn from the

page_text: rock and guide or rest shaft D to the breast beam. By this arrangement an
angle or bend is formed in the warp threads where they pass over the whip
roll. Strain or tension upon the warp yarns between the yarn beam and the
breast beam of course tends to straighten each yarn, and lessen the bend or
angle formed at the bearing point of the leaf C by depressing it. One end of
the shaft D overhangs its bearing, and bas there fixed to it a tipping lever
marked E, the ends of the lever projecting therefrom in opposite directions.
To one end of the lever a weight H is hung, and from the other end a rod P
is pendant, being guided in the vertical movement imparted to it by a hole in
the ear d. A short shaft K is journaled in one side of the frame with its ends
projecting on each side; the end inside bears a pinion J, which meshes into
a gear I, said gear being fixed on the yarn beam and forming one of the beads
thereof; on the other or outside end of K is fixed an escapement wheel L. On
a stud a fixed in the frame, and near the upper portion of the escapement, is
hung the detent or pallet lever M, so arranged that its teeth or pawls c and b
can operate on the escapement in the manner usual for similar devices, that
end of M, which bears c, being made sufficiently heavy to cause tooth c
normally to remain in gear with the teeth of the escapement and prevent its
turning, except when c is raised out of gear for the purpose, and by the means
to be described. The tendency of the weight H is, as will be seen, to keep
the whip roll or tension leaf elevated, so as to make the bend or angle in the
warp yarns, and some suitable stop is arranged for the weight to keep it from
falling too far, and from raising the whip roll too high when the yarn is
exhausted from the beam, and when an empty beam is exchanged for a full
one. As the lay beats up the filling thread, and as the take-up mechanism
operates, and as these together produce tension on the warp yarn, it will be
seen that while the escapement is held from turning no yarn can be unwound
from the beam, and that therefore the requirement of the weaving operation
for warp yarn must be supplied by straightening the warp, which straightening
depresses C and elevates the weight H, and causes P to descend at each blow
of the lay till the detent lever M is moved by impingement of P against it,
so as to bring the tooth or pawl 6 fully into gear in a notch of the escape-
ment wheel, which lifts the tooth or pawl c a little more than fully out of the
notches of said wheel, then as the lay beats back from the filling the stress on
the warp yarns is partially relieved, and the weight can descend a little, which
raises the rod P, and consequently the pawl b rises, so that the yarn beam is
then free, and is turned sufficiently by the tension on the yarn to prevent c
from catching in the notch from which it was last raised out of, and as the
yarn beam slightly turns and lets off yarn it is clear that the whip roll will
2

page_text: rise by the gravity of the weight H, and that P will also rise, so that the
escapement is free to turn till the pawl c falls into the next notch. As the
yarn thus gives off from the yarn beam the weight H causes it to be kept taut
and under an even tension, because the whip roll or tension leaf rises and
again establishes the angle in the yarn, from which the supply of warp yarn is
immediately furnished to the requirements of the weaving. The entire motion
of the escapement permitted by one rise and descent of the weight is equal to
the distance apart of two of its adjacent teeth.
The direction of motion of the escapement wheel, the warp beam, the warp
yarn, and the whip roll is shown by the arrows thereupon marked. When the
beam is filled with yarn it is obvious that more of it is released at each move-
ment of the escapement than when less yarn is upon the beam. The only
result of this, however, is that the escapement turns oftener as the quantity
upon the beam diminishes, the tension upon the yarn being kept equal by
the vibration, of the whip roll governed by the weight without regard to the
frequency of the let-off' movement of the yarn beam, the tension produced being
equal from a full to an empty beam. I prefer to have the number of teeth
or notches in the escapement wheel, & the number of teeth in the pinion and
gear so proportioned as to allow a movement of about nine notches of the
escapement to every ten beats of the lay when using up the last of the yarn
wound upon the warp yarn beam, but this proportion may be considerably
varied so as to admit of a movement of a less number of notches. It will be
observed that the yarn is not let off from its beam during the operative stroke
of the lay, but only during its retreating or return stroke, and that therefore
the impulse or beat up of the lay cannot change the tension upon the yarn
by letting off yarn from the beam at this forward stroke. Modifications may
of course be made in the arrangement and construction of the mechanism
embodying my Invention without departing from the spirit thereof though the
disposition and construction shown is considered the best.
In witness whereof, I, the said Lewis Reese Chesbrough, have hereunto
set my hand and seal, this Fourth day of March, Oue thousand eight
hundred and sixty-four.
LEWIS REESE CHESBROUGH. (L.S.)