IMPROVED MECHANISM FOR PRODUCING AN AUTOMATIC TENSION OF CHAINS UPON ALL HAND OR MECHANICAL WEAVING LOOMS
Year: 1876

page_text: LETTERS PATENT to Leon Petit, of St. Quentin, in the Department of the
Aisne, and Republic of France, Engineer, for the Invention of "IMPROVED
MECHANISM FOR PRODUCING AN AUTOMATIC TENSION OF CHAINS UPON ALL
HAND OR MECHANICAL WEAVING LOOMS."
Sealed the 18th May 1877, and dated the 25th November 1876.
PROVISIONAL SPECIFICATION left by the said Leon Petit at the Office of the
Commissioners of Patents on the 25th November 1876.
LEON PETIT, of St. Quentin, in the Department of the Aisne, and Republic of
France, Engineer. "IMPROVED MECHANISM FOR PRODUCING AN AUTOMATIC TENSION
OF CHAINS UPON ALL HAND OR MECHANICAL WEAVING LOOMS."
The principle upon which my Invention is based is that of the automatic move-
ment of weights upon steelyards always in proportion to the diameter of the warp
beam of weaving looms in general; thus if the beam decreases in diameter the
weights recede upon the steelyards towards their fulcrum. The unwinding of the
warp is rendered gentle and regular by the aid of a brake, preferably of steel plate,
which comes between the cords and the beam and prevents irregular friction of
these cords. This brake is not dependent upon the tension gear, and may be
dispensed with, the remainder of the mechanism working without it.
Upon the Sheet of Drawing hereunto annexed the parts drawn in black repre-
sent ordinary parts of the loom, those drawn in red representing mechanism of my
Invention.
In Figure 1A, B, C, indicate the frame of the loom; D, back beam carrying the
warp; the steelyards E are inclined so that the weights attached to the spindles
of the pulleys G have always a tendency to run down them, but are held back by
chains H and lever I, one part of which always pressing against the warp beam can
only vary its position when the diameter of the beam lessens; these movements will
be readily understood upon a careful inspection of the Drawing. Thus if the beam D
decreases in diameter, the part I which presses against the beam through the
medium of a plate of polished glass carried by the jointed bracket K rises, the part I
lowers, and the weights S which are only held by this lever returning towards their
fulcrum, the tension produced by these weights by the intermediary of the steel

page_text: yards on the cords L lessens, the spring brake slackens, and the warp is subject to
less strain; in this way the tension will always be in ratio with the diameter of the
warp roller.
The return pulley T is set on the axle of lever 1.
Figure 2 shows the mechanical arrangement of the brake. M, brake made of
plate steel, upon which is riveted a stop N keying into the support O fixed to the
frame of the loom; the object of this stop is to keep the break from turning with
the beam.
In Figure 1 it will be seen that the lever I may move in its sheath R, which
with the variation allowed in every direction to the support N permits the regu-
lation of the travel on the steelyards, as may be desired. This support N carries
the entire mechanical arrangement, and is bolted on the frame.
The shape of the various parts composing this mechanical arrangement may be
modified according to the looin to which they are to be applied. Whatever may be
the No. of the warp or of the woof employed the tension will always be the same,
and once regulated no further regulating is needed. This mechanical arrangement
is very simple for the workman, and may be adapted to any kind of loom.
To render my Invention applicable to every kind of loom I may modify it as
follows I may use a round steelyard screw tapped in part of its length and
carrying a ring with inner screw thread corresponding with that on the steelyard
upon which it moves to and fro; this ring is provided with a hook to receive the
tension weights. This steelyard may turn in its bearing, and at the same time
make the downward movement required by the movement of the tension cords; at
one of its ends it carries a toothed wheel moved by the adjusting roller, and intended
by turning the steelyard to bring back the screw-threaded ring which carries the
weight towards the fulcrum of this steelyard.
A pinion of a size regulated by the number of yards of warp contained on the
back or warp beam is applied at one of the ends of the adjusting roller, and gives
the rotary motion to the screw-threaded steelyard by means of a band chain. There
is here only question of one steelyard, the other is that of the ordinary loom
which may be used; it is only necessary to mount the weights upon a pulley, as
shown in Fig. 1; a small chain communicating with this pulley is attached to
the screw-threaded ring of the other steelyard, and consequently the weight of the
non screw-threaded steelyard will retire towards its fulcrum. This movement is
explained in reference to Fig. 1.
The driving pinion might be placed upon the axle of the back roller, but in this
case the proportional regulating which depends upon the number of revolutions of
this roller is more difficult.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Leon Petit in the Great Seal Patent Office on the 24th May 1877.
LEON PETIT, of St. Quentin, in the Department of the Aisne, and Republic of
France, Engineer. "IMPROVED MECHANISM FOR PRODUCING AN AUTOMATIC TENSION
OF CHAINS UPON ALL HAND OR MECHANICAL WEAVING LOOMS."
The principle upon which my Invention is based is that of the automatic move-
ment of weights upon steelyards always in proportion to the diameter of the warp
beam of weaving looms in general; thus if this beam or roller decreases in diameter
the weights recede upon the steelyards towards their fulcrum. The unwinding of
the warp is rendered gentle and regular by the aid of a brake, preferably of steel
plate, which comes between the cords and the warp beam, and prevents irregular
friction of these cords.
Upon the accompanying Sheet of Drawing, Figure 1 is an elevation of a machine
embodying my Invention; Figure 2 is a side view thereof; and Figures 3, 4, and 5
show details of the brake.

page_text: Description of the Apparatus. A support A, B, in two pieces is fixed to the cross
piece of the frame which is placed parallelly to the warp beam and beneath it. At
the top of this support is jointed a lever with arms of unequal length L, L', so
arranged that the length of these arms L, L', in relation to each other may be
modified at will. The shortest branch L carries at its end a wooden cross piece T,
which in order to lessen the friction and the number of points of contact is furnished
with two glass or porcelain rods, or rods or bars of other suitable material. This
cross piece comes horizontally upon the warp beam. The other arm L carries a
hook, to which are attached two chains C, C', which are fastened to the weights
P, P, of the steelyards after having passed over the friction rollers G, G. The
steelyards R, R', weigh as usual upon the cords which pass over the dressed roller
or warp beam, they are so adjusted that their end is higher than their fixed point
or fulcrum, as is in practice nearly always the case. Their upper part is made
perfectly true, and the weights by the aid of a roller and small spindle slide with
gentle friction along the steelyards.
The weights themselves instead of being of one piece may be replaced by a rod
or bar with head, upon which washers may be placed in sufficient number, according
to the nature of the fabric being woven.
Working of the Apparatus. The weights which at the beginning of the working
are at the end of the steelyards have a tendency to descend towards the fixed point
or fulcrum which is lower. They therefore exert by the aid of the chains C, C¹, an
effort tending to cause the arm L' of the lever to lower, and consequently the arm L
to rise; but the cross piece T coming against the dressed roller or warp beam cannot
rise excepting when the diameter of this roller decreases. It follows that the
weights redescend towards the fixed end or fulcrum of the steelyards to an extent
always proportional to the diminished diameter of the dressed roller or warp beam,
and that if (which is very easy) the travel of the weights has been properly
calculated there will be permanent compensation at each instant of the working, and
the tension upon the warp will be absolutely constant. This gives the long sought
solution of the problein of constant tension, solution as simple as it is complete,
because the journey of the weights is in direct connection with the variation of the
diameter of the warp beam without having to take into account either the number
of the warp or of the woof, nor of the shoots, and that this proportional variation
takes place in an absolutely automatic manner, and entirely does away with the
action of the weaver, who in the actual state of things has to move his weights by
hand.
I will now describe my improvement in the mode of action of the cords loading
the warp bean (see details Figs. 3, 4, and 5). Instead of letting the cord bear
directly upon the groove of the roller, I interpose between the cord and the roller a
flexible steel band or collar kept from moving by a spur which passes into a stop
piece in the frame of the loom. The cord tightens this steel band in the groove of
the roller, and causes it to act as a brake. Under these conditions the unwinding
of the warp takes place without jerks, without there being moments when the
pressure is too great, followed by a sudden rapid unwinding, as is the case under the
friction of the cord; neither the hygrometric state of the atmosphere, the temperature,
or other ordinary hurtful influences exercise any prejudicial effect when my improve-
ment is adopted.
It might be feared that the cross piece T might break the warp threads, and that
the apparatus would hinder the mending of the threads, but owing to the com-
pensating weight N which equipoises the apparatus, and to the glass rods with
which the piece T is furnished, the pressure borne by the warp is so slight, the
action of the lever so gentle, that no inconvenience results, and there is very little
danger of the breakage of a thread; should the weaver however require to get at
the warp beam my apparatus will in no way hinder him.
Having now described and ascertained the nature of my said Invention, and
in what manner the same is or may be performed, I would have it understood that
I do not confine myself to the precise details herein set forth and shewn on the

page_text: accompanying Sheet of Drawing, as such may be varied while retaining the essential
features of my Invention, and that I claim as secured to me by the herein-before
in part recited Letters Patent,—
Firstly. The apparatus for regulating the tension of the warp both in hand and
in power looms for weaving by the automatic movement of weights upon steelyards,
substantially as herein-before described and shown, Figures 1 and 2 of the accom-
panying Sheet of Drawing.
Secondly. The use of the brake shown in detail, Figures 3, 4, and 5 of the
Drawing, substantially as and for the purpose herein-before set forth.
In witness whereof, I, the said Leon Petit, have hereunto set my hand and
seal, this Eighteenth day of May, in the year of our Lord One thousand
eight hundred and seventy-seven.
LEON PETIT. (L.S.)