IMPROVEMENTS IN WARP TENSION AND LET-OFF MECHANISM FOR POWER LOOMS
Year: 1870

page_text: LETTERS PATENT to George Tomlinson Bousfield, of Loughborough
Park, Brixton, in the County of Surrey, for the Invention of
"IMPROVEMENTS IN WARP TENSION AND LET-OFF MECHANISM FOR POWER
LOOMS." A communication from abroad by Erastus Brigham
Bigelow. of Boston, in the United States of America.
COMPLETE SPECIFICATION filed by the said George Tomlinson Bousfield
at the Office of the Commissioners of Patents, with his Petition and
Declaration, on the 11th July 1870, pursuant to the 9th Section of
the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS. SHALL COME, I, GEORGE
TOMLINSON BOUSFIELD, of Loughborough Park, Brixton, in the County
of Surrey, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS IN
WARP TENSION AND LET-OFF MECHANISM FOR POWER LOoms," and have petitioned
Her most Excellent Majesty Queen Victoria to grant unto me, my
executors, administrators, and assigns, Her Royal Letters Patent for the

page_text: same, and have made solemn Declaration that it has been communicated
to me from abroad by Erastus Brigham Bigelow, of Boston, in the United
States of America.
NOW KNOW YE, that I, the said George Tomlinson Bousfield, do
hereby declare the nature of the said Invention to be as follows: —
In a Patent granted to the said Erastus Brigham Bigelow on the 26th
day of March 1867, No. 883, he describes, in combination with a vibrating
roller or bar, the varying position of which governs the delivery of the
warps, a spring arrangement whereby the tension of the warps is gradually
diminished whilst the shed is being formed and gradually increased to
an extent to resist the beat up whilst the shed is being closed, a single
mechanism being employed to produce the required tension both in the
open shed and in resisting the beat up.
In a Patent granted to George Tomlinson Bousfield on the 18th May
1870, No. 1437, being a communication from the said Erastus Brigham
Bigelow, a mode of accomplishing each of these objects is described,
one device being employed to produce the required tension of the warps
when the shed is open, and another one for increasing their tension to
resist the beating up of the cloth. In the Patent last referred to there
is also described in combination with the tension arrangement just
mentioned a let-off mechanism, the action of which is determined at
the time the lay beats up the cloth.
A part of the present Invention relates to a mode of constructing the
mechanism for increasing and diminishing the tension of the warps, and
consists in combining with the lever arm, whereby the tension of the
warps is increased, to withstand the beating up of the cloth, and diminished
whilst the shed is formed, a spring capable of being increased and
diminished in force according to the resistance required, independently
of the movement of said lever arm, and in combining said combined
lever arm and spring with a vibrator which by its varying position
governs the action of the let-off mechanism. And another part of the
Invention relates to the construction and arrangement of let-off mechanism
in combination with the mechanism which increases and diminishes the
tension of the warps and regulates their delivery.
Figure 1 of the annexed Drawings is an end elevation of the improve-
ments with such parts of a loom as are necessary to illustrate their
operation; Figure 2 is a rear elevation of the same; and Figure 3 is a
plan.

page_text: The loom frame is marked a, the lay b, and the lay shaft c. The:
warps, which are indicated by the line d, pass from the warp beam e
over a vibrating roller f (for which a bar may be substituted) to the cloth
forming line, as is usual, the cloth being taken up by a "positive take-up
motion" which is well known. The vibrator or vibrating roller f is
supported by arms g extending upwards from the shaft h which oscillates
in bearings i. To the shaft h an arm j is affixed, from which a weight k
is suspended by a strap 7, the weight being made in sections so that its
force may be easily adjusted to the requirements of different descriptions
of cloth, and in practice should be graduated so as to give the required
tension to the warps when the shed is open.
The combined lever arm and spring, the construction of which
constitutes a part of this Invention, may be understood as follows:-A
lever arm m is affixed to the shaft h, and has pivotted to its side a
spring n which is capable of vibrating between two stops o and ♪ pro-
jecting from the lever arm. An adjusting bolt q passes through the
spring and stop o, and is provided with nuts r by which the force of the
spring may be graduated. The spring is connected with the lay 6 by a
connecting rod s, lever arm t, and adjustable rod u, the object of inter-
posing the two last-named parts being to furnish a ready means of
varying the extent of the vibration imparted to the vibrator by the lay.
By a right and left handed nut v the length of the rod u may be
lengthened or shortened, and the extent of the movement it imparts
to the connecting rod s may be increased or diminished by elevating or
depressing stud w in the slot x of the lever arm t. In the Drawings
the spring n is represented as drawn forward by the lay away from the
stop p, but when the lay falls back the spring rests against the stop p,
and in that position may be increased or diminished in force independently
of the movement of the lever arm. As, for illustration, by screwing up
the nuts the lower end of the spring will be caused to press against
the stop p with increased force, and by unscrewing them it will be caused
to press with diminished force, so that the power with which the spring
will act on the vibrator when it is drawn forward by the lay may be
thus graduated independently of the movement of the lever arm.
From this description it will be seen that when the combined lever
arm and spring is drawn forward by the lay in beating up the cloth
the tension on the warps will be increased according as the spring is
graduated, and at the same time the vibrator or vibrating roller will be

page_text: allowed to take positions at different beats, varying according to the
length of the warps between the warp beam and take-up motion.
Then as the lay falls back the combined lever arm and spring goes back
with it and slackens the warps for the formation of the shed, a slot a³
in the connecting rod s serving to release the rod from its hold on the
spring n, and thus leave only the force of the weight k applied to them.
Though the weight and the combined lever arm and spring are
described as co-operating to produce the required tension on the warps
the combined lever arm and spring may be used, and are intended to
be used without the weight, and when so used the slot a³ should be
dispensed with.
The form and arrangement of the lever arm and spring may be varied,
whilst the advantages of adjusting the force of the spring independently
of the movement of the lever arm will be retained, as will be herein-after
explained.
The part of the Invention which relates to the mode of delivering out
the warps will now be described.
The warp beam e is turned to deliver out the warps by a let-off
shaft y, worms z, and gear a', as is usual the upper end of the shaft
being supported by a stand b' and the lower end by a step on the upper
side of a pipe bearing c¹. Another shaft d¹, supported by the pipe
bearing just mentioned is connected with the let-off shaft y by mitre
gears e¹ and has a ratchet wheel f¹ affixed to it, the object of interposing
this shaft being to bring the ratchet wheel into a convenient position
to be acted upon by the let-off mechanism. An elbow lever oscillates
on the outer end of the shaft d', the upright arm g¹ carrying a pawl h¹,
which engages with the ratchet wheel f¹, and its horizontal arm i
carries a weight, which draws the pawl back to renew its action when
left free to do so, its movement in that direction being limited by a
stop ¹ projecting from the loom frame. The upright arm g¹ has another
pawl jointed to it, which engages with a series of steps / on the
upper side of an arm projecting from the connecting rod 8 before
mentioned, the end m¹ of the pawl being bent so as to lie in the path
of the steps. The pawl is supported by a lever n¹, which oscillates on
a stud o¹ and has a projection p¹ extending from its forward arm on
which the pawl rests. The rear end of the lever n³ carries a cam q¹ on
which a roll on the inner side of the lever arm acts, slots being
provided for the adjustment of the cam and the roller respectively. On

page_text: the inner end of the rear arm of the lever n' a friction surface s¹ projects,
which is concentric with its axis and is acted on by another friction
surface on the edge of a lever arm & supported by a stud u', the latter
friction surface being drawn against the former with sufficient force to
hold the lever n' in position by a spring w¹. When the lay is moved
backwards an adjustable stud x on the inner side of the connecting
rod s strikes against the upper end of the lever arm t¹, and disengages
the friction surfaces and allows the weight of the pawl ¹ to raise the
rear arm of the lever n¹ until it is arrested by the upper end of the
friction surface & striking against a projection y¹ on the lever arm t¹.
The loom is represented in that stage of its operation in which the
lay beats up the cloth and in which the vibrator or vibrating roller
determines the action of the let-off mechanism. The length of the
warps between the warp beam and the take-up motion is also supposed
to be such as to prevent the spring n from drawing the lever arm m
forward far enough to raise the bent end of the pawl ¹ above the
lowest of the series of steps U, so that when the lay is moved backwards
it will turn the let-off mechanism to the fullest extent it is capable of
doing. Now, suppose that as the weaving goes on more warps are given
out than are taken up in the cloth and the length of the warps between
the warp beam and the take-up motion thereby increased, the spring n;
when the lay advances to beat up the cloth, will draw the lever arm m
forward accordingly, and cause the roller r¹, by acting on the cam q¹, to
raise the pawl k¹ to a position to engage with the second one of the
series of steps or to clear them altogether, the pawl ¹ being held in
position by the friction surfaces as before explained. If the pawl be
raised so as to engage with the second step it will be moved a less
distance than before, and if it be raised so as to clear them altogether,
the lay will be moved back but without moving it at all. It is
important to note that the stud x¹ at every backward movement of the
lay disengages the friction surfaces so as to allow the pawl to descend
to its lowest position, to be raised again when the lay beats up the cloth
according to the length of the warps, as just explained.
Figure 4 represents the spring n applied to the lever arm n in a spiral
form, and in a manner capable of being adjusted in force independently
of the movement of the lever arm. The angle at which the warps pass
from the warp beam over the vibrator or roller f varies with the
diameter of the warps on the beam, it being more obtuse when the beam

page_text: is full than when it is nearly empty. To give the warps an uniform
angle, and consequently a more uniform tension, they are sometimes
passed around the shaft h and thence over the roller f as indicated in
Figure 4.
A modification of the combined lever arm and spring and the mode
of combining it with the vibrator are represented in Figures 5, 6, and 7.
These Figures also represent other modes of constructing and arranging
the let-off mechanism than that above described. These arrangements
of let-off mechanism are convenient ways of carrying out the system
of let-off mechanism described in the Specification of 'the before-men-
tioned Patent granted to George Tomlinson Bousfield on the 18th May,
1870 (No. 1437).
In the Figures 5, 6, and 7, the warps are represented as passing from
the warp beam to the take-up motion in the same manner as in Figure 1,
and the warp beam is turned to deliver out the warps by an elbow
lever and intermediate mechanism in the same manner as that already
described. A vibrator or vibrating roller a² is supported by arms b²,
extending rearwards from a shaft c² which oscillates in bearing d². A
pulley e oscillates on a stud f², and has a segment of gear teeth g
formed on its inner side, which engage with another segment of gear
on the end of an arm h² affixed to the shaft c², so that when the pulley
is oscillated it causes the roller a² to vibrate correspondingly, and when
moved in one direction it tightens the warps, and when moved in the
opposite direction it slackens them. A weight is suspended from
the pulley by a strap which gives the required tension to the warps
when the shed is open. A lever arm² is loosely fitted to the stud f²,
and is capable of vibrating between two stops 12 and m², projecting from
the outer side of the pulley. A spring n² is pin jointed at o² to the
front edge of the lever arm, and has its upper end resting against the
stop m², whilst its lower end is held in position by an adjusting bolt p
which passes through the spring and lever arm and is secured by nuts
q by which the force of the spring may be graduated.
By inspecting the Drawings it will be seen that the spring by resting
against the stop m³ presses the lever arm against the stop 1, so that
the force of the spring may be increased or diminished independently
of the movement of the lever arm, according as the nuts q² are adjusted.
The lever arm is connected with the lay 62 by a connecting rod 12², and
vibrates with it. When the lay is moved forward to beat up the cloth

page_text: it draws the lever arm forward, and causes the spring by pressing
against the stop m² to increase the tension on the warps at the time the
lay beats up, and allow the vibrator or vibrating roller at different beats
to take positions varying according to the varying lengths of the warps
between the warp beam and the take-up motion. Then when the lay.
falls back the lever arm and spring go back with it and slacken the
warps for the formation of the shed.
The let-off mechanism may be understood as follows:-The upright
arms of the elbow lever before referred to has a pawl & jointed to it,
which engages with a series of steps u² on the upper side of an arm
projecting from the connecting rod ² before mentioned. The forward
end of the pawl is supported by a lever arm v² which oscillates on a
stud w, and has a projection x2 on which the pawl rests. The rear
end of the lever arm v² is supported by another lever arm y³, which
oscillates on a stud 22, and is drawn against the end of the lever arm v²
by a spring ³, the lower end of the lever arm y² being provided with
a series of steps c³ (corresponding in number with the series of steps u²),
on which the end of the lever armrests. The lever arm v² is con-
nected with the pulley e² by a connecting rod d³, provided with a slot e³
which plys on a stud projecting from the pulley, the use of the slot
being to allow the pulley to turn when the warps are slackened with-
out pressing on the lever arm v². In the Drawings the length of the
warps between the warp beam and the take-up motion is supposed to
be such as to prevent the spring n² (when the lay is in its forward
position as represented) from turning the pulley e² far enough to raise
the lever arm v² above the lowest of the series of steps c³, thus leaving
the pawl in a position to engage with the lowest of the series of
steps, so that when moved backwards by the lay it will turn the
let-off mechanism to the fullest extent it is capable of doing. Now
suppose that as the weaving goes on more warps are given out than
are taken up in the cloth, and the length of the warps between the
warp beam and the take-up motion is thereby increased, the spring m²
when the lay advances to beat up the cloth will turn the pulley e², so
as to raise the lever arm v² to a position to engage with the second or
third of the series of steps c³, according as the length of the warps may
be. If it be raised so as to engage with the second one it will cause
the pawl to engage with the second one of the series of steps u² which
will turn the let-off mechanism a less distance than before, and if it

page_text: be raised so as to engage with the third one it will raise the pawl ³
above the steps u², and the lay will fall back without turning the let-off
mechanism at all. At each backward movement of the lay an adjustable
stud on the inner side of the connecting rod ³ pushes the lever
arm y² away from lever arm u², far enough to release it and allow it to
descend and rest on the lowest of the series of steps c³ until it is again
raised in the manner just explained. The number of steps in each of
the series may be varied according to the requirements of the cloth to
be woven.
In some cases only one step in cach place is employed, but
two or more are generally preferred.
The form and arrangement of the mechanism may be varied without
departing from its distinguishing principles. As, for example, Figure 6
represents a modified arrangement in which the shaft d' is dispensed
with and the ratchet wheel f¹ and lever s² are placed on the let-off
shaft y.
In this position the lever s² vibrates in a horizontal plane, and
at one end carries the pawl & which engages with the steps u², and at
the other the pawl h¹ which acts on the ratchet f¹.
Figure 7 represents another modified arrangement in which the
fulcrum of the pawl 2 and steps u² are transposed, that is to say, the
steps u² instead of being applied to the connecting rod r² are applied to
the arms, and the pawl 2 instead of being jointed to the arm s² is
jointed to the connecting rod ². In this arrangement the pawl moves
the steps, instead of being moved by them, though the result is the same
in both cases.
The several parts of the mechanism herein described may be inter-
changed without changing the distinguishing features of the Invention,
as, for instance, the combined lever arm and spring as represented in
Figure 5 may be used in connection with the vibrator or vibrating roller
arranged and operated as represented in Figure 1. The lever and
adjustable connecting rod for varying the extent of the vibration given
to the vibrator or vibrating roller by the lay represented in Figures 1, 2,
and 3 may be used in connection with the arrangement of mechanism
represented in Figures 5, 6, and 7. The series of steps for holding
the pawl in position represented in Figure 5 may be used in place of
the friction surfaces represented in Figure 1, and vice versa. So also
the let-off mechanism herein described may be used and is intended to
be used in combination with a vibrator and spring arrangement for
giving tension to the warps and regulating their delivery, whether said

page_text: vibrator be governed wholly by one device or by one device for pro-
ducing the tension of the warps when the shed is made, and another
for increasing their tension to withstand the beating up of the cloth.
Having described the Invention, and pointed out some of the modi-
fications of which it is susceptible without departing from its distin-
guishing principles, what is claimed as new is,―
First. Combining with a lever arm by which the tension of the warps
is increased to withstand the beating up of the cloth, and diminished
when the shed is made, a spring capable of being adjusted so as to
increase or diminish its force independently of the movement of said
lever arm, substantially as and for the purpose specified.
Secondly. Said lever arm and spring combined, as herein described, in
combination with a vibrator which by its varying position governs the
action of the let-off mechanism substantially as specified.
Thirdly. Let-off mechanism constructed, arranged, and operated as
herein described, in combination with a vibrator and spring arrangement
whereby its action is governed and the tension of the warps increased
and diminished substantially as specified.
In witness whereof, I, the said George Tomlinson Bousfield, have
hereunto set my hand and seal, this Eleventh day of July, in the
year of our Lord One thousand eight hundred and seventy.