IMPROVEMENTS IN LETTING-OFF APPARATUS FOR LOOMS
Year: 1883

page_text: LETTERS PATENT to James Schofield of Littleborough in the County of
Lancaster, Manufacturer and Joseph Ebenezer Bentley of the Same place,
Manager for an Invention of "IMPROVEMENTS IN LETTING-OFF APPARATUS
FOR LOOMS
"
PROVISIONAL SPECIFICATION left by the said James Schofield and Joseph
Ebenezer Bentley at the Office of the Commissioners of Patents on the
5th February 1883.
JAMES SCHOFIELD of Littleborough in the County of Lancaster, Manufacturer
and JOSEPH EBENEZER BENTLEY of the same place, Manager, "IMPROVEMENTS IN
LETTING-OFF APPARATUS FOR LOOMS
"
Our Invention relates principally to the looms used in the weaving of heavy
goods such for example as fustians but is also applicable to looms used in the
weaving of other goods. The object of our Invention is to obtain a positive letting
off of the warp. Upon the axle of the warp beam we fix a worm-wheel with
which gears a worm upon a side shaft. Upon the said side shaft is fixed a second
worm wheel with which gears a worm which we prefer shall be double in order
that the worm wheel shall be of a suitably large diameter. The last named worm
is fixed upon the same shaft as or is secured to a ratchet wheel or two or more
ratchet wheels. A pawl or two or more pawls engaging with the said ratchet
wheel or wheels is or are connected with the sley sword in such a manner as that
as the warp beam empties the stroke of the pawl or pawls is or are lengthened.
In one arrangement a stud on the pawl or a pin upon which the pawl is mounted
engages with a slot in a piece which is secured to the sley sword and is raised in
the said slot as the weaving proceeds by means of a lever which is provided or

page_text: connected with a feeler which is in contact with the warp upon the beam. The
arrangement may be modified by employing a screw motion worked by gearing
from the worm shaft or from a suitable part of the loom to raise the pawl stud or
pin in the slot or the slot may be in a lever which is actuated by the sley sword
or by a suitable part of the loom. We may employ a smooth edged wheel and
holding dogs instead of the ratchet wheel or wheels and pawl or pawls.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said James Schofield and Joseph Ebenezer Bentley in the Great Seal
Patent Office on the 4th August 1883.
JAMES SCHOFIELD of Littleborough in the County of Lancaster, Manufacturer,
and JOSEPH EBENEZER BENTLEY of the same place, Manager,
"IMPROVEMENTS IN
LETTING-OFF APPARATUS FOR LOOMS
"
Our Invention relates principally to the looms used in the weaving of heavy
goods such for example as fustians but is also applicable to looms used in the weaving
of other goods. The object of our Invention is to obtain a positive letting-off of the
warp. Upon the axle of the warp beam we fix a worm wheel with which gears a
worm upon a side shaft. Upon the said side shaft is fixed a second worm wheel
with which gears a second worm, which is fixed upon the same shaft as or is
secured to a ratchet wheel or to two or more ratchet wheels. A pawl or two or
more pawls engaging with the said ratchet wheel or wheels is or are connected
with the sley sword in such a manner as that as the warp beam empties the stroke
of the pawl or pawls is or are lengthened.
In order that our Invention may be fully understood we have attached hereunto
a sheet of drawings made to a scale of about three inches to the foot and marked
with letters of reference. In the said drawings Fig 1 represents a side elevation
and Fig 2 a plan of so much of a loom as is necessary to the proper illustration of
our Invention. In the said Figs a is one of the loom sides.b is the warp beam c is
the crank shaft and d is the sley sword these parts being of ordinary or suitable
form and construction. Upon one end of the warp beam we fix a worm wheel e
with which gears a worm which is fixed or formed upon a side shaft g which
revolves in bearings h, h which are bolted to the loom side. Upon the front end
of the said side shaft is fixed a worm wheel i with which gears a worm / which is
upon a short shaft 1. The said shaft is mounted to revolve in bearings in a
bracket m which is secured to the loom side and upon the said shaft is fixed a
ratchet wheel n. Three or a suitable number of pawls o are mounted upon a pin p
and the ends of this pin slide in slots in the two side cheeks of a frame which
is secured to the sley sword. The pin p is suspended by means of a link from the
front end of a levers which is mounted upon a fulcrum ț. The rear end of the

page_text: said lever is formed with a broad curved face g¹ which rests upon the warp which
is upon the beam. As the rear arm of the said lever is longer and heavier than the
front arm the end s¹ tends to sink and thereby to lift the pin p carrying the pawls
towards the upper ends of the slots in the frame this tendency being restrained
by the warp which sustains the preponderating end of the lever. It will be seen
that when the pin p is in its lowest position it will be comparatively near to the
fulcrum of the sley sword and as a consequence when the said sley sword
vibrates the pawls will have a comparatively small movement imparted to them
and as the said pin is raised the movement of the pawls is increased. The parts
are so proportioned as that when the pin is in its lowest position the movement
of the pawls is sufficient to cause the warp beam to have the requisite movement
when full and that as the beam empties and the end 8' of the lever sinks the pin p
will be so proportionately raised as that the movements of the warp beam shall be
accelerated to an extent proportionate to its reduction in diameter.
The pawls
vary in length so that the ratchet-wheel can be turned at each movement to an
extent equal to a fractional part of the length of one tooth or to the extent of two
or more teeth and a fractional part as is well understood.-The action of the
apparatus is as follows:-As the sley vibrates the fulcrum pin p carrying the
pawls is moved to and fro and the pawls acting upon the ratchet wheel turn it to
some extent at each beat of the sley. This movement of the ratchet wheel causes
the shaft g to rotate in a lesser degree and the worm on the said shaft permits the
warp beam to make the slight movement necessary to the delivery of the warp.
These movements being repeated for each pick of the loom the warp is gradually
"let-off" a sufficient quantity being "let off" for each pick of the loom. As the
coiled warp upon the beam becomes less in diameter the end s¹ of the lever sinks
thereby lifting the fulcrum pin of the pawls which then make an increased move-
ment and turn the ratchet-wheel to a greater extent so that each movement of the
warp beam is increased in amount in order to equalise the delivery of the warp.
By the employment of the compound motion consisting of two worms and two
wheels great command over the warp beam is obtained so that the strain upon the
beam caused by the tension of the warp has no power to turn back the ratchet-
wheel. Another advantage arising from the use of the compound worm motion is
that the movement of the ratchet wheel being considerable as compared with the
movement of the warp beam great exactness and facility of regulation are
obtainable. The shaft can be turned by means of a handle placed upon its
squared end at times when it is necessary to turn back the warp beam or otherwise
to turn the beam when the loom is at rest or the said shaft may be provided with
a hand wheel for the purpose. In order to obtain greater exactness we may
substitute a friction motion for the ratchet wheel as for example we may employ a
smooth edged wheel acted upon and prevented from moving back by holding dogs.
As the strain upon the ratchet wheel is comparatively small we are enabled to use
a fine toothed wheel so that we can take two teeth or more at the commencement
of a new warp. In practice we use a wheel having about twice as many teeth as
the one shewn in the drawings. To prevent the ratchet wheel from over-running
or from turning back we apply a simple friction brake indicated by u in Fig 2. In
some cases we may interpose change wheels between the ratchet wheel or first
motion and the first worm in order to be able to regulate the rate of delivery of
yarn to suit various weights and counts of cloth. We may vary the arrangements
for raising the pawls as the warp beam empties. In some cases we may use a
screw motion connected by means of gearing with the side shaft or with a suitable
part of the loom the screw acting upon a nut or part which gradually raises the
fulcrum of the pawls as the weaving proceeds. We may employ a special
vibrating lever to carry the pawls instead of using the sley sword for that
purpose.
Having now fully set forth and indicated the nature of our said Invention and

page_text: the manner in which we carry the same into practical effect we would have it to be
understood that we claim :—
First. The combination of parts applied to a loom for the purpose of turning the
warp beam to let off the warp with a regulated movement substantially as set
forth and indicated hereinbefore and in and by the accompanying drawings.
Secondly. Giving movement to the warp beam of a loom by means of a compound
worm and wheel motion regulated by means of a feeler to increase the movement
as the warp beam empties substantially as set forth and indicated.
And lastly. The ratchet wheel actuated by a pawl or by pawls mounted on a
fulcrum which is moved as the warp beam empties to lengthen the stroke of the
pawl or pawls in combination with a compound or double geared worm and wheel
motion substantially as and for the purpose set forth and indicated.
In witness whereof We the said James Schofield and Joseph Ebenezer Bentley
have hereunto set our hands and seals this third day of August in the year of
our Lord one thousand eight hundred and eighty-three
Signed, sealed and delivered}
presence
EDWARD K. DUTTON
41 John Dalton St, Manchester.
(L.S.)
JAMES SCHOFIELD
JOSEPH E. BENTLEY (L.S.)