Improvements in the Let-off Mechanism of Looms for Weaving.
Year: 1890

page_text: Date of Application, 5th Feb., 1890
Complete Specification Left, 3rd Nov., 1890-Accepted, 29th Nov., 1390
PROVISIONAL SPECIFICATION.
Improvements in the Let-off Mechanism of Looms for Weaving.
We, JOSEPH LINDSAY, and ROBERT LINDSAY, of Somerville Place, Dundee, in
the County of Forfar, North Britain, Engineers, do hereby declare the nature of
this invention to be as follows, that is to say :-
Our said invention has for its object to improve the construction and action of
certain parts of looms for weaving, the parts principally referred to being those
which have to do. with the tension of the warps and are connected with the warp
beam.
In carrying out the invention we impart the required tension to the warp by
means of a frictional appliance acting directly or indirectly on the warp beam, and
actuated by weighted levers; and in order to obtain uniform tension notwithstanding
the continually diminishing diameter of the warps on the beam we employ mechanism
deriving a regulating action from, and in exact accordance with, the varying
diameter itself, of the warps. In one modification of our improved mechanism a
lever having at its end a palm or suitable part to touch the warps on the bean is
kept in contact with the warps by a weight or spring. This lever has fixed to it a
toothed sector which gears with a pinion on a transverse horizontal shaft situated at
the lower part of the loom; and this shaft has on each end a specially shaped cam
which acts on a link connected to a rod arranged to transmit the pressure from the
weighted lever to the frictional appliance. The action of the cam moves the rod
gradually further from the fulcrum of the weighted lever as the diameter of the warps
on the beam diminishes and thereby causes the effective pressure on the frictional
appliance to be diminished in a manner to keep the tension of the warps uniformi.
The weighted levers may have the weights fixed directly on them or applied to
them by ropes or chains passing over pulleys; or springs may be substituted for the
weights.
We use an improved frictional appliance consisting of fixed brake blocks, which
may he arranged with rubber or other elastic connection above the drag heads or
friction pulleys of the warp beam, and movable brake blocks below, the latter being
pressed upwards by the weighted levers. When it is necessary to turn back the
warp beam the levers being relieved in any convenient way, the lower brake blocks
descend and the beam also descends clear of the upper fixed brake blocks and rests
by its end journals in bracket bearings on the loom framing so that it can be easily
turned.
By another improvement instead of applying the frictional brake blocks directly
upon the warp beam they are applied to short shafts held permanently in bearings
in the side frames of the loom and these short shafts have spur wheels or pinions
fast on them, in positions to gear with spur wheels or pinions formed or fixed on the
ends of the warp beams. With this arrangement the beam can be put into and
lifted out of its place without interfering with the drag or tension mechanism; and
the pinions on the beam can be made small enough to allow of the end disks or
flanges of the beam being made each in a single piece and be passed over the pinions
to their positions on the beam.
The drag or tension mechanism may be applied to one end only of the warp beam.
or to both ends as hereinbefore described.
n
11
1
1000
EDMUND HUNT,
Applicants' Agent.

page_text: COMPLETE SPECIFICATION.
Improvements in the Let-off Mechanism of Looms for Weaving.
We, JOSEPH LINDSAY, and ROBERT LINDSAY, of 4 Somerville Place, Dundee, in
the County of Forfar, North Britain, Engineers, 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, that is to say :-
Our said invention has for its object to improve the construction and action of
certain parts of looms for weaving, the parts principally referred to being those
which have to do with the tension of the warps and are connected with the warp
beam.
In carrying out our invention we impart the required tension to the warps by means
of a frictionl appliance acting directly or indirectly on the warp beam, and actuated
by weighted levers; and in order to obtain uniform tension notwithstanding the con-
tinually diminishing diameter of the warps on the beam, we employ mechanism
deriving a regulating action from, and in exact accordance with, the varying diameter
itself of the warps.
And in order that our said invention and the manner of performing the same may
be properly understood we hereunto append a sheet of explanatory drawings to be
hereinafter referred to in explaining our improvements.
Figure, 1, of the drawings is a sectional plan, and Figure, 2, is a corresponding
sectional elevation of an arrangement in which the frictional appliances are applied
directly to a warp beam.
Figure, 3, is a back elevation explanatory of a modified arrangement.
In these drawings the same reference numerals are used to mark the same or like
parts wherever they are repeated.
In Figure, 2, a part of the inner side, 4, of one of the side frames or gables of the
loom is shown, along with the parts of the improved mechanism near that gable;
and Figure, 1, shows in plan only the parts shown at the lower part of Figure, 2, the
upper parts being supposed to be cut away. The dotted portion of a circle, 5, in
Figure, 2, indicates the size of the end disks of the warp beam and the maximum
diameter of the warps on the beam, but the beam is supposed to be cut away, to show
the friction pulley or drag head, 6, and the journal or gudgeon, 7. The friction
pulley, 6, is indicated by dotted lines in Figure, 1.
In the modification shown in Figures, 1, and 2, a lever, 8, having at its upper end
a palm, 9, or suitable part, to touch the warps on the beam, is kept in contact with
the warps by a weight, 20, on a bellcrank arm, or it might be by a spring. This
lever, 8, is fast on a rocking shaft, 10, which has also fast on it a toothed sector, 11,
which gears with a pinion, 12, on a shaft, 13 and this shaft has on it at or near each
end, a specially shaped cam, 14, which acts on a link, 15, jointed to a radius lever, 16,
and connected to a rod, 17, arranged to transmit the pressure from a weighted
lever, 18, to the frictional appliance. The action of the cam, 14, moves the rod, 17,
gradually further from the fulcrum of the weighted lever, 18, as the diameter of
the warps on the beam diminishes, and thereby causes the effective pressure on the
frictional appliance to be diminished in a manner to keep the tension of the warps
practically uniform. The rod, 17, has its lower end fitted to slide upon a curved
arm, 18a, fixed on the rocking shaft which has also fixed on it the weighted
lever, 18. The weighted levers, 18, may have the weights fixed or adjustably fitted
directly on them, or applied to them by ropes or chains passing over pulleys; or
springs may be substituted for the weights. With a directly applied weight the
fulcrum of each lever is between the weight and the acting part as shown in
Figures, 1, and 2. With a weight applied by a rope passing round a pulley the
acting part of each lever may be between the weight and the fulcrum.
We use an improved frictional appliance consisting of a fixed brake block, 19,
which may be arranged with rubber or other elastic connection, above each drag
head or friction pulley, 6, combined with a movable brake block, 21, below, the

page_text: latter being pressed upwards by means of the weighted lever, 18, through the
arm, 18a, and rod, 17, which last has its upper end jointed to the brake block, 21.
The upper end of the rod, 17, is also connected to the framing, 4, by a radius
link, 22, or it may he guided in any other convenient way. The upper brake
block, 19, is held by an arm, 23, which is centered on a stud fixed in the framing, 4,
to allow of its being raised when placing or removing a warp beam, the arm being
locked in position by means of a cor piece, 24, centered on another fixed stud.
When it is necessary to turn back the warp beam, the levers, 18, being relieved in
any convenient way, the lower brake blocks, 21, descend and the beam also descends
with its friction pulleys, 6, clear of the upper fixed brake blocks, 19, and rests by
its end journals, 7, in the bracket bearings of the loom framing so that it can be
easily turned.
By another improvement, instead of applying the frictional brake blocks, 19, 21,
to pulleys or drag heads, 6, fixed directly on the warp beam, they are applied at
each end of the beam to a pulley, 6, fast on a short shaft, 25, as shown in Figure, 3,
this shaft, being held in bearings in the side frame, 4, of the loom, and having on it
a spurwheel or pinion, 26, in a position to gear with a spurwheel or pinion, 27, formed
or fixed on the end of the warp beam. The brake blocks and parts connected with
them are not shown in Figure, 3, but are to be arranged substantially as shown in
Figure, 2.
With this arrangement the beam can be put into and lifted out of its
place without interfering with the drag or tension mechanism; and the pinion, 27,
on the beam can be made small enough to allow of the end disk or flange, 28, of the
beam being made in a single piece and being passed over the pinions to its position
on the beam.
The drag or tension mechanism may be applied to one end only of the warp beam,
or to both ends as hereinbefore described.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. In combination as tension or drag mechanism applicable to warp beams of looms
for weaving, a lever following the diminishing diameter of the warps on the beam
and by a toothed sector and pinion turning a cam which shifts parts so as to alter
the leverage acting on the drag or frictional appliance the parts being arranged and
acting substantially as hereinbefore described.
2. Applying friction to the warp beams of looms by means of fixed or stationary
upper brake blocks or frictional appliances, and lower movable upwardly pressed brake
blocks or frictional appliances, substantially as hereinbefore described.
3. Applying friction to the warp beams of looms by means of brake blocks acting
on pulleys or drag heads which are geared to the beams by toothed wheels, sub-
stantially as hereinbefore described.
Dated this First day of November 1890.
BUMU
Applicants' Agent,