An Improved Means and Method of Automatically Regulating the Let-off and Tension of Warps in Looms.
Year: 1892

page_text: Date of Application, 17th June, 1892
Complete Specification Left, 7th Oct., 1892-Accepted, 26th Nov., 1892
PROVISIONAL SPECIFICATION.
An Improved Means and Method of Automatically Regulating the
Let-off and Tension of Warps in Looms.
RICHARD WILBY Mill Manager Exchange Buildings Marsh Huddersfield, do
hereby declare the nature of this invention to be as follows:-
The objects of this invention are to provide a ratchet worm and wheel let-off
motion for looms, which shall possess a pawl mechanism so constructed, that it can
be governed, and controlled by a pivoted back bearer which oscillates to the
requirements of the shedding, in order that an uniform degree of tension may be
kept on the warp threads during every part of the pick cycle, and to make this
let-off mechanism so that it will be automatic, and capable of unwinding the warp
from the beam as the weaving proceeds at one regular, and uniform degree of
tension at all times, in order that the same number of picks may be put into each
inch of the cloth woven, and also in order that the weaver may be completely
relieved from all care, and management, of the tension of the warp, and of the
strength of the cloth which is being woven, and these objects I effect by the
following means, and method.
On and near to one end of the warp beam, and preferably just inside that loom
frame to which the take up motion is attached, is fixed a worm wheel, in the teeth
of which is geared a worm, which is fixed on the end of a shaft said shaft being
prolonged to the front of the loom, and there provided with a hand wheel for
convenience to the weaver. About midway on this shaft is fixed a broad ratchet
wheel, and on each side of this ratchet wheel, and concentric with said shaft, is
placed a bell crank lever capable of oscillating on the shaft. The upright arms of
each of these bell crank levers carries a stud, on which works a pawl capable of
engaging with the teeth of this ratchet wheel, while each of the other arms of the
bell crank levers are bored near their ends, so as to receive the turned ends of a
three armed T shaped lever, which lever is bored at the juncture of the three arms
so as to be capable of oscillating on a pivot stud which is firmly screwed into a
bracket bolted to the loom frame, said bracket having cast upon it a couple of
bearings for ratchet wheel shaft, which bearings adjoin each bell crank lever and
keep them in position on the shaft. The downward arm of the T shaped lever is
coupled by a knuckle joint to a short horizontal connecting rod, while the other end
of this connecting rod is coupled by a similar joint to the slay sword, and partakes
of its motion, which motion is communicated by the T lever in opposite directions
to each of the bell crank levers which carry the pawls, thus giving a nearly
continuous motion to the ratchet wheel, and shaft, when said pawls are in gear with
the teeth of the ratchet wheel.
The principle involved in the new features or novelties which are contained in my
pawl mechanism, and which enable me to put the oscillating pawls under governable
control of an oscillating pivoted back bearer, is to couple or join the oscillating
pawls to a non-oscillating part at a point preferably as near to the centre line of the
pawls oscillatory motion as it is possible to get, and to make the surface of one of
the two joined parts in contact a curved surface, the curve being struck by a radius
equal to the distance of the said centre of motion from such points of contact, so
that the oscillating part can travel in contact with the non-oscillating part, in its
own free circular path. This non-oscillating part can then be coupled to the
vibrating pivoted back bearer of the loom, so as to be lifted, or depressed at each
change of position of back bearer's vibration, which actions put the pawls into, or

page_text: out of gear with the teeth of their ratchet wheel, according as warp is required, or
not required to be unwound from the beam.
One way of successfully applying the above principle to a ratchet worm and wheel
let-off motion is as follows. The pawls are cach provided with a spring to ensure
quickness, and certainty of action, and at about two thirds their length from their
free ends the pawls have each a horizontal pin, or stud fixed firmly in one of their
sides, on each of which pins loosely fits a small connecting rod, which connecting
rods run down alongside the pawl arms towards the centre of motion, where each of
their lower ends rest on the top surfaces of levers, or arms, said levers being joined
in one, and possessing a common axis at their other ends, which axis works on a
pivot stud firmly screwed to a lug which is cast on the afore mentioned bearing
bracket. The upper surfaces of these two levers, or arms, where the small connecting
rods coupled to the pawls rest upon them, are each curved to a radius equal to the
distances of such surfaces from centre of ratchet wheel shaft, which allows the
connecting rods to travel in their own free circular paths, and so prevents abberation
in the working of the pawls while oscillating. 1 balance the weight of the pawls,
the connecting rods, the double lever, and the downward force of the pawl springs,
by placing a spiral spring on the axial stud of the double lever, and causing it to
press upwards on the lever with the necessary force, and in order to make the whole
pawl mechanism stable enough to remain in any position placed, I cause the spiral
spring to give an end pressure to the axis of the double lever to act as a brake.
When this double lever is lifted, it lifts both the pawls out of gear with the teeth
of their ratchet wheel by means of the two small connecting rods which are coupled
to the pawls, and which rest on the arms of this double lever, and when said double
lever is depressed, the pawls are again free to engage with the teeth of the ratchet
wheel.
The method I employ for coupling this double lever to the pivoted back-bearer
of the loom, is as follows. The double lever has a hole bored through a lug cast
on one of its arms, the hole being about one-third or one-fourth the length of the
arm from its pivoted end, and through this hole a vertical rod passes, which rod is
coupled at its upper end by a knuckle joint to a horizontal arm, which arm proceeds
from the pivoted back bearer of the loom, and partakes of its oscillations. Or
instead of this horizontal arm, the said rod may be coupled to the pivoted back
bearer by a wire, said wire, and rod being joined together by a bell crank lever,
which works on a pivot stud screwed to the loom frame, the angle between the two
arms of the lever being arranged to give the proper change of direction in the
oscillatory motion. The lower end of the rod in this case is coupled to a tension
spring fastened to loom frame, the elastic force of which causes wire, and rod to
vibrate with the pivoted back bearer. On this vertical rod in either of the above
arrangements, are placed two collars, whose positions on the rod are adjustable by
set screws. One is placed above, and the other below the hole in double lever,
their distance apart on the rod being arranged to be about one-sixteenth part of an
inch greater than the amplitude of vibration of the rod, added to the thickness of
the metal of the lever which lies between said collars.
The new features which I have invented for my pivoted back bearer, in order to
make said back bearer suitable for controlling my pawl mechanism while perfectly
free to oscillate to the requirements of the shedding, are as follows. The curve or
rounded part of the back bearer over which the warp threads have to pass, is
divided along the line where the warp threads first touch the back bearer when
entering upon it at the time when a full warp beam is in the loom, into two parts,
and these rounded parts are seperated about two and a half inches from each other
by a flat portion, which flat portion is tangent to each half of the seperated curved
portions. This form of back bearer permits it to oscillate at so great an inclination,
that the warp threads are always ensured of entering upon said back bearer near to
its centre of oscillatory motion which condition is very essential in order to get a
uniform tension on the warp with different states of fulness of the warp beam.
I
also so arrange the axes or journals of my pivoted back bearer by setting them

page_text: backwards, as will cause the line of centre of its oscillatory motion to lie along the
surface of the bottom curve, for the purpose of preventing friction, and chaufing of
the warp threads over said back bearer when oscillating.
I employ springs on the back bearer to balance the total tension of the warp
threads, and these springs I attach to arms on the back bearer at such an angle, as
will cause their leverage to increase as the back bearer moves backward, in order
that I may get the same degree of tension on the warp threads when the sheds are
closed, as when they are fully open, and in order to make the pivoted back bearer
almost frictionless, I fix these springs on that side of the back bearer where their
force on the back bearer will act against the resultant of the forces of the warp.
On looms where the pivoted back bearer will not sufficiently resist the blow of the
reed, I employ an arm on the back bearer, and a cam, or short arm fixed on the
crank shaft, the point of the cam, or short arm, being arranged to come into contact
with the pivoted back bearer arm, at the instant of each beat up of the weft, so as
to take the force of the blow, and by employing a spring on this back bearer arm,
I can obtain a cushioned beat up.
When the loom is in action, the slay sword gives oscillatory motion in opposite
directions to each of the bell crank levers carrying the pawls, and the back bearer
vibrates to the requirements of the shedding, thereby causing the rod with its two
collars which passes through the hole in double lever to vibrate.
When the upper
collar comes into contact, and depresses the double lever, both pawls are put into
gear with their ratchet wheel, and warp is delivered from the beam until the lower
collar owing to the vibrations of back bearer taking place a little backward, comes
into contact, and lifts the double lever, and so puts both the pawls clear of the
teeth of their ratchet wheel, to be again put into gear when the upper collar again
depresses double lever on account of pivoted back bearer performing its vibrations
in its former position again.
By the employment of the means, and method herein described, I am able to let
off the warp from the beam automatically, at one uniform degree of tension from
full, to empty beam, and yet ensure a constant tension in the pick cycle, by employing
a pivoted back bearer to govern the pawl mechanism of this let-off motion, which is
perfectly free to vibrate to the requirements of the shedding.
Dated this 17th day of June 1892
RICHARD WILBY.
COMPLETE SPECIFICATION.
An Improved Means and Method of Automatically Regulating the
Let-off and Tension of Warps in Looms.
I, RICHARD WILBY, of Exchange Buildings, Marsh, near Huddersfield, Mill
Manager, 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 :-
This invention relates to a ratchet mechanism whose pawls are operated into and
out of gear by a vibrating pivoted back bearer, and the objects of this invention
are, firstly, to ensure an even degree of tension on the warp threads during each
pick cycle; secondly, to deliver the warp from the beam as the weaving proceeds
at one uniform degree of tension from full to empty beam.
The annexed drawings serve to illustrate my invention, wherein Fig. 1
represents so much of a loom as is necessary to shew how my mechanism is
fixed and applied.
Figs. 2, 3, 4, etc., are detailed parts of the mechanism.
I will now describe my invention and explain that the oscillating motion to work
the pawls 9 is obtained from the slay sword 16, and that the delivery of the warp
is regulated and controlled by the slightly varying position of the arc of vibration
of the pivoted back bearer 33, which bearer is made to operate the pawls 9 into

page_text: and out of gear with the teeth of their ratchet wheel 6 as the delivery of the
warp requires, and the mechanism which thus puts the oscillating pawls 9, into
communication with and under governable control of the oscillating pivoted back
bearer 33 contains most of the new features of my invention.
Referring to Figs. 1, 2, 4, and 5, number 1 is a worm wheel fixed on and near to
one end of the warp beam 2, in the teeth of which is geared a worm 3, which worm
is fixed on the end of a shaft 4, said shaft being prolonged to the front of the loom
and there provided with a hand wheel 5 for convenience to the weaver.
6 is a
ratchet wheel keyed on said shaft and 7, 7, are bell crank levers of the shape
shewn in Fig. 4 which oscillate on said shaft, one on either side of the ratchet
wheel 6. The upright arms of each of these bell crank levers are provided with
a stud 8, 8, on which works a pawl 9, 9, capable of engaging with the teeth of the
ratchet wheel 6. 7ª, 7, (Fig. 4) are the second arms on the bell crank levers,
and each have a slot 7 to receive the ends 10" 10" of a T shaped lever 10
(see Fig. 5). This lever 10 is suitably bored so as to fit and oscillate upon a
stud 11 (see Fig. 2) which stud is firmly screwed into the bracket 12. Bearings 13
are made on this bracket to receive the shaft 4 and also serve to keep the bell
crank levers 7, 7, in position on the shaft. Vibratory motion is given to the two
bell crank levers 7, 7, through the medium of the connecting rod 14 (Fig. 1) which
is attached by knuckle joint to the hanging arm 10% of the T shaped lever 10.
This connecting rod 14 is attached at its other end by a similar joint 14 to
a bracket 15 which is bolted to the slay sword 16 and partakes of its motion when
the loom is in action, thus giving through the medium of the connecting rod 14,
Tshaped lever 10, bell crank levers 7, 7, and pawls 9, 9, a nearly continuous
motion to the ratchet wheel 6, shaft 4, and warp beam 2, when the pawls 9, 9, are
gear with said ratchet wheel
in
So far described and illustrated, this mechanism would deliver the warp from
the beam at every pick when the loom was in action, and other things being equal,
the rate of such delivery at any one time would entirely depend upon the size
of the roll of yarn upon the beam at that time.
I will now describe the mechanism which puts the oscillating pawls 9, 9, into
working communication with the oscillating back bearer 33 (see Fig. 1) which
mechanism causes the varying position of the arc of vibration of the said bearer to
operate the pawls 9, 9, into and out of gear with the teeth of the ratchet wheel 6,
thereby causing the warp to be automatically delivered from the beam to the
requirements of the weaving, and at a uniform degree of tension, the said
mechanism between the pawls 9, 9, and the back bearer 33 for effecting this
automatic delivery of the warp, forms the new features in my invention.
Referring to Figs. 1, 3, and 4, the numerals 17, 17, are pins fixed firmly in the
sides of the pawls 9, 9, at about two thirds the pawl's length from their free ends.
18, 18, are hanging pins or pendants of the shape shewn in Fig. 4 and hinged on
the pins 17, such said pendants passing down between guides 7, 7º, cast or fixed
on arms 7, 7, to as near the centre of oscillating motion as is possible, on account
of the diminished oscillating motion at those points. 20, 20, 20ª, (Fig. 3) are arms
carrying lugs 21, which are bored so as to be capable of working on the stud 21.
22 is a lug cast on bearing bracket 12 to which lug the stud 21 is firmly screwed.
23, 23, (see Figs. 1 and 3) are springs made of ribbon steel which are rivetted on the
underside of the arms 20, 20 in a state of tension pressing upwards on the ends of
the arms with a force just equal to promptly lift the pawls 9, 9, without deflecting.
These springs project about three fourths of an inch beyond the lever ends 20, 20,
and are curved at these parts 23ª, 23ª, (Fig. 3) the radius of the curves being
struck from centre of ratchet wheel shaft 4. The pawl pendants 18, 18,
(Figs. 1 and 4) rest on the top of the curved portions of these springs 23, 23,
(Fig. 1) and are of such a length that when the pawls rest in the bottom of the
teeth of the ratchet wheel 6, the ends of the pawl pendants are only just clear of
the springs 23, 23.
The arm 20, (Figs. 1 and 3) has a knife edge 24 filed on it, and about one

page_text: eighth of an inch from this, is another knife edge 25 made on a suitable piece of
steel which is fixed in the lug 26 cast on bearing 13, (Fig. 2.).
Between these two knife edges is a double action spring 27 (see Fig. 7), a very
good form of which is shewn and made of ribbon steel.
When the two knife edges as shewn in Fig. 7 are in line with a radius of the
treble armed lever 20ª, the force of the double action spring on treble armed lever
is neutral, but when the knife edge 24 is above or below the other knife edge 25,
the action of the spring is to lift or depress the three armed lever 20%. The use
of this double action spring is to make the pawls change promptly and complete,
and also for the purpose of insuring that the pawls 9, 9, shall always be either
fully in gear or completely out of gear with the ratchet wheel 6.
When the three armed lever 20, 20, 20ª, (see Figs. 1 and 3) is lifted, it raises
both the pawls 9, 9, clear of the teeth of the ratchet wheel 6, by means of the
springs 23, 23, and pawl pendants 18, 18, and when the three armed lever is
depressed, the pawls are again free to engage with the teeth of their ratchet
wheel.
In order to give the necessary limit to the motion of the three armed lever, the
part 20° is made to work in a slot 26ª filed in lug 26 on bearing 13 (see Fig. 2)
and the vertical depth of this slot determines how much the pawls 9, 9, shall rise
clear of the teeth of the ratchet wheel 6, when said pawls are out of gear. This
three armed lever is put into communication with the back bearer 33, by the
horizontal arm 28, (Fig. 1,) fixed on the back bearer, and which partakes of its
oscillating motion. This rod is reduced in thickness about midway of its length
for the purpose of giving slight elasticity thereto.
This arm 28 is coupled by knuckle joint 28" to the vertical rod 29, passing
through hole 20" in arm 20. This rod 29 is provided with threaded parts as
shewn, on which are two nuts 30, 30, and two lock nuts. The distance between
the inner surfaces of these two nuts is adjusted to be about a quarter of an inch
greater than the amplitude of vibration of rod 29, plus the thickness of the
metal 20 which lies between said nuts. To give the required tension to the warp
I attach springs 32, 32, to arms 31, fixed to the back bearer 33 (see Fig. 1,) and
the angle between the said arms and the springs instead of being at right angles as
is usual, are arranged to be about 40 or 45 degrees of arc as shewn, so that the
leverage of the springs on the back bearer will increase as the back bearer moves
backward. This angular arrangement of the springs is adapted for the purpose of
compensating for the increased leverage of the warp threads on the back bearer as
it moves backward, and also for the purpose of compensating for the slackening of
the springs as the back bearer moves backward, so as to insure the same degree of
tension on the warp wheu the sheds are closed as when they are fully open. A
stop piece 34 is provided for the back bearer 33, to take the force of the springs 32
whenever the warp has to be slackened, the stop being adjusted to be about one
eighth of an inch beyond the backward limit of vibration of pivoted back bearer.
The number of teeth in ratchet wheel 6, and in worm wheel 1, are arranged to
give warp sufficiently quick when the beam is nearly empty as will suffice when
weaving the coarsest cloth usually woven in such looms, and when each of the
pawls are continuously in gear, and each taking a single tooth per stroke.
The modus operandi is as follows:-Starting with the pawis 9, 9, in gear, and
the back bearer 33 vibrating so that neither of the nuts 30, 30, on the rod 29
come into contact with the arm 20°, (Fig. 1). Under these conditions (for the
moment), the warp will be given off at a quicker rate than is required in the
weaving, which extra length delivered is taken up by the back bearer 33 vibrating
in an arc a little backward. Immediately the excess of delivery over consumption
has reached a predetermined amount say one twentieth part of an inch, the lower
nut on rod 29 comes into contact with arm 20° and lifts it, thereby raising both
the pawls 9, 9, out of gear with the teeth of the ratchet wheel 6, and stopping the
delivery of the warp until the excess of delivery is used up, at which stage the
upper nut 30 comes into contact with arm 20" and depresses the three armed lever,

page_text: permitting both the pawls to fall into gear, and starting the delivery again, to be
again stopped in the same manner, when the excess of delivery has again reached
one twentieth part of an inch, and again re-started, when this excess of warp has
been used up.
It must be distinctly understood that this slightly varying position
of the are of vibration of back bearer 33 does not in the slightest degree alter the
tension or tightness of the warp, and although the delivery is intermittent, yet the
tension on the threads is kept perfectly uniform at all times.
Very little force is required from the back bearer to effect the changes from
delivery to non-delivery, and vice versa, which permits of the pawl mechanism
being made extremely sensitive, and the double action spring 27, always insures
the changes being prompt and complete.
The function of the steel ribbon springs 23, 23, (see Figs. 1 and 3) is to allow
of the three armed lever 20ª being lifted when either of the pawls 9, 9, are locked
in gear with the teeth of the ratchet wheel 6, the spring yielding at such times,
and its elasticity afterwards lifting the pawl out of gear at the instant it is freed
from its tooth.
The reason why I employ a double ratchet mechanism, instead of a single one,
is because only half the length of stroke of pawl arm is required, which permits me
to get the oscillating motion for the pawls (even on fast running looms), from the
slay sword, instead of from the cam shaft 37, this again reduces the length of the
stroke by one half on account of double speed of slay sword, so that the pawls
need only turn the ratchet wheel one tooth each per stroke, which reduces the
momentum of the ratchet wheel shaft 4 which momentum is checked if necessary
by a small brake strap 35, one end of which is fastened to the loom frame, the
other end having a small weight 36 hung on it, the strap passing in a groove over
the hand wheel 5.
In order to prevent the varying angle of the warp threads 38 as they enter upon
the back bearer 33 (due to the varying size of the roll of yarn on the beam)
exerting a varying leverage on back bearer, and so altering the tension of the
warp as the weaving proceeds, I make said back bearer of the shape shewn in
section 33, (see Figs. 1 and 6.).
As the drawings shew, the curved or rounded part over which the warp threads
have to pass is divided along a line where the warp threads first touch the back
bearer when the fullest warp beam is in the loom into two parts 33ª, 33, (Fig. 6)
and these rounded parts are separated from each other by a distance of from two
and a half to three and a half inches. I use this form of back bearer because it
yields sufficiently to the requirements of the shedding when it is oscillating at an
angle great enough to insure the warp threads entering upon said back hearer at
the same distance from the centre line of its oscillating motion 33 when the fullest
warp beam is in the loom, as when the said warp beam is nearly empty, this
condition being essential in order to obtain with a balanced back bearer one
uniform tension on the warp with varied angles of the threads 38 as they enter
upon said back bearer. On looms where the back bearer will not resist the blow
of the reed, I employ an arm on the back bearer, and a cam or short arm fixed on
the crank shaft, the point of the cam or short arm being arranged to come into
contact with the back bearer arm, at the instant of each beat up of the weft, so as
to take the force of the blow. The variations in the position of the arc of vibration
of pivoted back bearer, (due to the letting off being intermittent), and which are
greatest at full beam, may be reduced to one half their usual amount (if thought
desirable) by suspending one of the pawls 9 out of gear during the time of weaving
the first half of each warp. This will not interfere with the working of the other
pawl. The idle pawl must be set working again when about half the warp has
been woven.
By the employment of my improved warp let-off mechanism, the warp can be
automatically delivered from the beam as the weaving proceeds at one uniform
degree of tension from full to empty beam, and yet an even degree of tension on
the warp during each pick cycle is insured by employing a pivoted back bearer

page_text: to govern the pawl mechanism of this let-off motion, which back bearer is perfectly
free to vibrate to the requirements of the shedding.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
Firstly. In ratchet mechanism used for the purpose of letting-off the warps in
looms, the pawls of which are operated into and out of gear by a pivoted back
bearer which vibrates freely to the requirements of the shedding, the use in
combination therewith of the arm 28, (Fig. 1) and rod 29, with its adjustable
nuts 30, 30, set at a distance apart on the rod 29, about a quarter of an inch greater
than the amplitude of vibration of the rod, plus the thickness of the metal 20ª
which lies between the nuts, the said rods being used for the purpose of imparting
a slight movement to the three armed lever 20, 20, 20, whenever the position of
the arc of vibration of pivoted back bearer 33 changes backward or forward a
predetermined amount, this motion or movement being communicated through the
medium of the pawl pendants 18, 18, to the pawls 9, 9, so as to operate said pawls
into and out of gear with the ratchet wheel 6, substantially as herein set forth.
Secondly. In ratchet mechanism used for the purpose of letting-off the warps
in looms, the use in combination therewith of the three armed lever 20, 20, 20%,
(Fig. 3) pivoted on a common axial stud 21, and capable of a limited motion on
this axis, the three armed lever being used for the purpose of forming a medium of
connection and communication between the oscillating pawls 9, 9, and the
oscillating pivoted back bearer 33, and arranged to receive a slight movement
from the oscillating pivoted back bearer, whenever the position of its arc of
vibration changes backward or forward a predetermined amount, this motion being
communicated through the pawl pendants 18, 18, to the pawls 9, 9, thereby
operating said pawls into and out of gear with the teeth of the ratchet wheel 6,
according as warp is required or not required to be delivered from the beam,
substantially as herein described and illustrated.
Thirdly. In a ratchet mechanism used for the purpose of letting-off the warps
in looms, the use in combination therewith of the pawl pendants 18, 18, working on
the pins or studs 17, 17, together with the guide lugs 7, 7, cast or fixed on the
pawl arms 7, 7, the whole being used for the purpose of getting a working
connection between the oscillating pawls 9, 9, and the arms 20, 20, these working
connections being preferably got at points 23ª, 23, (Fig. 1) as near to the pawl's
centre line of oscillating motion as is possible, because of the diminished oscillatory
motion at those points, substantially as herein set forth.
Fourthly. In a ratchet mechanism such as herein shewn and described and used
for the purpose of letting-off the warps in looms, the use in combination therewith
of the steel ribbon springs 23, 23, rivetted on the underside of lever arms 20, 20,
(Fig. 3) in a state of tension, so as to press upwards on the ends of the arms, the
lower ends of the pawl pendants 18, 18, (Fig. 1) resting on the top of these springs
near their ends, the springs being used for the purpose of preventing interference
with the lifting of the three armed lever 20, 20, 20, when one of the pawls 9, 9,
happens to be locked in gear with the teeth of the ratchet wheel 6, the springs
yielding at such times, and permitting the three armed lever to be lifted, the
elasticity of the spring afterwards lifting the said pawl clear of the teeth of the
ratchet wheel, at the instant such pawl becomes unlocked from its tooth, sub-
stantially as herein set forth.
Fifthly. In a ratchet mechanism used for the purpose of letting-off the warps
in looms, the use in combination therewith of the curved form of the springs 23, 23,
at those points 23ª, 23ª, (Fig. 3) where the pawl pendants 18, 18, rest upon them,
the curves of said parts being concentric with the shaft, substantially as herein
set forth.
Sixthly. In a ratchet mechanism such as herein shewn and described and used
for the purpose of letting-off the warps in looms, the use in combination therewith

page_text: of the double acting spring 27, placed between the two knife edges 24, and 25,
(Figs. 2 and 3) and used for the purpose of ensuring that the pawls 9, 9, shall
always be either fully in gear or completely out of gear with the teeth of the
ratchet wheel 6, and also for the purpose of making the changes in the pawl
mechanism from delivery to non-delivery and vice versa prompt and complete,
substantially as herein set forth.
Lastly. The general arrangement, construction and combination of parts as
herein set forth and illustrated by the drawings of mechanism for automatically
controlling the delivery of warps in looms by the varied position of the arc of
vibration of pivoted back bearer."
Dated this 6th day of October 1899
TASKER & CROSSLEY,
Halifax, Agents.