AN IMPROVED LETTING OFF MOTION FOR LOOMS
Year: 1880

page_text: LETTERS PATENT to James Williamson, Manufacturer, John Swindells, Mill
Manager, and George Swindells, Mill Manager, all of Lancaster, for an
Invention of "AN IMPROVED LETTING OFF MOTION FOR LOOMS."
PROVISIONAL SPECIFICATION left by the said James Williamson, John
Swindells, and George Swindells at the Office of the Commissioners of
Patents on the 10th December 1880.
JAMES WILLIAMSON, Manufacturer, JOHN SWINDELLS, Mill Manager, and George
SWINDELLS, Mill Manager, all of Lancaster. "AN IMPROVED LETTING OFF
MOTION FOR LOOMS."
This Invention relates to an improved letting off motion for looms, and has for
its object the automatic weighting and letting off the yarn from the warp beam, so
that only as much is let off as is taken up, and, further, the maintenance of a
constant and uniform tension of the warp from the beginning to the end without
adjustment after the first setting.
For this purpose we employ a horizontal lever at one or both ends of the warp
beam. To this horizontal lever is jointed a vertical arm, which, as well as the
lever, may be straight, bent, or curved. The lever is pivotted on a pin secured to
the loom side, and the angle between it and the vertical arm is so placed as to
include the neck or collar of the warp beam, projections being formed upon both
the lever and arm in such a manner as to embrace the neck or collar of the warp
beam.
The lever and vertical arm are connected by a spiral or other spring, the tension
of which causes the neck of the warp beam to be firmly gripped, and thus prevents
the revolution of the beam. The warp beam being nearly balanced by means of a
weight carried upon the further end of the horizontal lever, is freely suspended
by means of the warp which passes over a rounded bar or rest at the back of the
loom.
The upper part of the vertical arm is so arranged that it comes in close proximity
to the back top corner of the loom side, upon which there is fixed a bracket or
bearing carrying a cam or movable contact piece.
As the taking up motion proceeds the warp beam is lifted, and carries with it
the jointed lever and arm, the upper end of which is thus brought with a gradually

page_text: increasing pressure against the cam or contact piece. As soon as this pressure
equals or exceeds the tension of the spring the grip of the jointed lever and arm is
released, and the warp beam actuated by the unbalanced portion of its weight
revolves and falls, carrying with it the jointed lever and arm. The latter being
thus removed from the cam or contact piece the spring becomes free to again grip
the neck or collar of the warp beam, the further revolution and descent of which
are thus prevented. This series of movements is automatically repeated as often
as may be demanded by the process of weaving and by the taking up motion.
Two brackets may be attached to the backs of the loom frames to form a temporary
support for the warp beam and to arrest its fall when requisite.
When it is necessary to rewind the warp beam the cam or contact piece is
pressed by hand against the upper end of the vertical arm, by which means the
pressure of the jointed lever and arm upon the neck of the warp beam is removed,
and the latter may be freely rotated as desired.

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page_text: Having described the nature of the said Invention, and the manner of performing
it, we wish it to be understood that we do not confine ourselves to the precise
details of the construction of the several parts of the apparatus hereinbefore
described and illustrated on the accompanying Drawings, and that what we claim
is,―
The letting off motion consisting of the balanced compound lever and spring and
the warp beam partly suspended by means of the warp and partly supported by
the balanced compound lever, substantially as described and illustrated in the
accompanying Drawings.
In witness whereof, I, the said John Swindells, on my own behalf, and on
behalf of the said James Williamson and George Swindells, have hereunto
set my hand and seal, this Seventh day of June, in the year of our
Lord One thousand eight hundred and eighty one.