An Improved Let-off Motion for Looms for Weaving.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
An Improved Let-off Motion for Looms for Weaving.
I, HERMANN WOLF, of 17, Karl-strasse, Lodz, in the Empire of Russia, Engineer,
do hereby declare the nature of this invention to be as follows:-
My invention relates to let-off motions for looms for weaving.
In the automatically regulating warp-beam brakes heretofore known, in addition
to cords or ropes and chains, band-brakes are employed, which, however, do not
fulfil the required functions. A band-brake, on account of the rapid wear and its
too sudden action, is only suitable in cases where the brake is to be temporarily or
seldom used, or where it is actuated for the purpose of bringing a machine entirely
to rest; not, however, where the brake, as in warp-beam brakes, must be con-
tinually in action and is only employed for gradually slowing down or retarding
or for gradually partially releasing the moving part. The block-brakes heretofore
known, in so far as they are used on warp-beams, cannot here be considered, since
they do not work automatically.
In order to obviate the aforesaid disadvantages incidental to band-brakes, accord-
ing to the present invention, a block-brake is used, of which one block is rigidly
mounted, whilst the other block, which is movable, is arranged to be acted upon by
a spring and is in connection, through levers and links, with pivoted arms carrying
the lath or roller for supporting the warp, so that the swinging motions of
these carrier-arms, determined by the varying tension of the warp or chain, are
transmitted to and act on the brake and the apparatus is thus automatically
regulated. The arrangement is very simple in construction and can be adapted for
use with warp-beams of various widths."
1
For the reception of the fixed brake-block, a frame or brake-saddle is employed
which can be secured in any suitable manner to the frame of the machine. The
movable brake-block, which, in the arrangement hereinafter mentioned, is arranged
at the top, is mounted in a brake-arm which can be turned about a pivot-pin, which
arm is pressed down by means of a spiral spring surrounding a pivotally supported
bolt. The said spring rests at one end against the brake-arm and at the other end
against a compound nut or combined nut and rotatable sleeve which is screwed onto
the said bolt. The latter is pivoted at its lower end to any suitable fixed part of the
apparatus, preferably to the lower brake-frame, by the aid of a pivot-pin which
passes through an oval hole or eye in the said bolt. The automatic engaging and
releasing of the brake-arm is effected by the lath or roller over which the warp or
chain threads pass and are supported as they leave the warp-beam, this lath or
roller being mounted on swinging arms. From the said swinging arms, which are
pivotally attached to the frame of the machine, is suspended a bolt or thrust rod
the lower end of which acts on the end of a double-armed pivoted lever. Against
the other end of the said double-armed lever abuts a rod pivotally attached to the
brake-arm carrying the movable brake-block. Should the warp or chain-threads
unwinding from the warp-beam and passing over the said lath or roller, be more
tightly stretched than corresponds to the braking force exerted by the spring

page_text: acting on the brake-arm, for the time being, the lath or roller supporting the warp
yields to this pressure so as to descend a little. By reason of this, the swinging
arins and the thrust-rod are also moved downwards, which imparts an oscillating
motion to the double-armed lever and, by the further medium of the rod attached
to the brake-arm, the raising of the brake-arm and the release of the
warp-beam are effected. The result of this is, that the warp or · chain-
threads unwind freely from the warp-beam, so that the incipient tension
on the warp is relaxed and the
condition again
original
Since a sudden variation of tension does not ordinarily take place, the alteration
in the tension of the warp-threads rather takes place gradually, corresponding to
the decreasing diameter of the warp-beam, and thus also the alteration of the
automatically controlled braking action takes place gradually.
occurs.
The weight of the said lath or roller and of the rods or levers connected thereto,
is counter-balanced by a spring which surrounds the thrust-rod and rests against an
adjustable collar on this rod. At its other end the spring rests against a loose ring
which is supported by an arm secured in any suitable manner, preferably to the
fixed brake-frame or saddle.
The arrangement is designed in such a manner that the brake-arm can be raised,
and the warp-beam conveniently interchanged. For this purpose, the compound
nut can be screwed off from the pivoted bolt, the spring removed and the rod
detached from the double-armed lever. In order to enable warp-beams of different
width to be inserted, the mechanism is preferably arranged so as to be adjustable
in a direction transverse to the frame of the machine. The lower brake-saddle or
frame rests, for this purpose, on a transverse bar of uniform prismatic form in
cross-section, the pivot-or hinge-pin of the movable brake-arm is similarly
adjustable in its seat or bearing and the double-armed lever, at the end at which the
thrust rod is supported, is formed with a broad part with a number of notches or
recesses in which the said thrust-rod can engage.
In order to be able to weave backwards, a hand-lever is pivotally attached to the
lower brake-bearing or brake-saddle, by means of which hand-lever it is possible to
act on a special arm or lever in connection with the double-armed fever. By
actuating this hand-lever, a nose or cam-shaped end thereof is pressed against the
said arm so that the double-armed lever raises the rod and the movable brake-arm
connected therewith. The weaver can then turn the warp-beam by hand as
desired.
The above-mentioned mechanism can be arranged, as desired, either on one side
or on both sides of the loom.
I, HERMANN WOLF, of 17, Karlstrasse, Lodz, in the Empire of Russia, Engineer,
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:
In the automatically regulating let-off motions or warp-beam brakes heretofore
known, in addition to cords or ropes and chains, band-brakes are employed, which,
however, do not fulfil the required functions. A band-brake, on account of the

page_text: rapid wear and its too sudden action, is only suitable in cases where the brake is
to be temporarily or seldom used, or where it is actuated for the purpose of bringing
a machine entirely to rest; not, however, where the brake, as in let-off motions or
warp-beam brakes, must be continually in action and is only employed for gradually
slowing down or retarding or for gradually partially releasing the moving part.
The block-brakes heretofore known, in so far as they are used on warp-beams,
cannot here be considered, since they do not work automatically.
In order to obviate the aforesaid disadvantages incidental to band-brakes, accord-
ing to the present invention, a block-brake is used, of which one block is rigidly
mounted, whilst the other block, which is movable, is arranged to be acted upon by
a spring and is in connection, through levers and links, with pivoted arms carrying
the lath or roller for supporting the warp, so that the swinging motions of
these carrier-arms, determined by the varying tension of the warp or chain, are
transmitted to and act on the brake and the apparatus is thus automatically
regulated. The arrangement is very simple in construction and can be adapted for
use with warp-beams of various widths.
In the accompanying drawing,
Figure 1 is a side elevation,
Figure 2 a front elevation, and
Figure 3 a plan, showing my improved let-off motion or brake applied to
a loom.
For the reception of the fixed brake-block 5, a frame or brake-saddle 3 is
employed which can be secured in any suitable manner to the frame of the
machine. The movable brake-block 6, which, in the arrangement hereinafter
described, is arranged at the top, is mounted in a brake-arm 4 which can be turned
about a pivot-pin 7, this arm being pressed down by means of a spiral spring 9
surrounding a pivotally supported bolt 10. The spring 9 rests at one end against
the brake-arm 4 and at the other end against a compound nut or combined nut
and rotatable sleeve 12 which is screwed onto the bolt 10. The latter is pivoted
at its lower end to any suitable fixed part of the apparatus, preferably to the lower
brake-frame 3 by the aid of a pivot-pin 11 which passes through an oval hole or
eye in the bolt 10. The automatic engaging and releasing of the brake-arm 4 is
effected by the lath or roller 19 over which the warp or chain threads pass and are
supported as they leave the warp-beam, this lath or roller being mounted at 18 on
swinging arms 16. From the arms 16 which are pivotally attached at 17 to the
frame of the machine, is suspended a bolt or thrust red 15, the lower end of
which acts on the end of a double-armed lever 14 pivoted on a pivot-pin 14.
Against the other end of the double-armed lever 14 abuts a thrust-rod 13 pivotally
attached to the brake-arm carrying the movable brake-block. Should the warp or
chain-threads unwinding from the warp-beam 2 and passing over the lath or
roller 19, be more tightly stretched than corresponds to the braking force exerted by
the spring 9 acting on the brake-arm, for the time being, the lath or roller support-
ing the warp yields to this pressure so as to descend a little. By reason of this.
the swinging-arms 16 and thrust-rod 15 are also moved downwards, which imparts
an oscillating motion to the double-armed lever 14 and, by the further mediuin of
the rod 13, attached to the brake-arm, the raising of the brake arm and the release
of the warp-beam are effected. The result of this is, that the warp or chain-
threads unwind freely from the warp-beam, so that the incipient tension on the
Since a sudden variation
warp is relaxed and the original condition again occurs.
of tension does not ordinarily take place, the alteration in the tension of the warp-
threads rather takes place gradually, corresponding to the decreasing diameter of
the warp-beam, and thus also the alteration of the automatically controlled braking
action takes place gradually.
The weight of the lath or roller 19 and of the rods or levers 16, 15 connected
5 thereto, is counter-balanced by a spring 22 which surrounds the thrust-rod 15 and
At its other end the spring rests
rests against an adjustable collar 23 on this rod.

page_text: against a loose ring 21 which is supported by an arm 20 secured in any suitable
manner, preferably, to the fixed brake-frame or saddle 3.
The arrangement is designed in such a manner that the brake-arm can be raised,
and the warp-beam conveniently interchanged. For this purpose, the nut 12 can
be unscrewed from the pivoted bolt 10, the spring 9 removed and the rod 13
detached from the double-armed lever 14. In order to enable warp-beams of
different width to be inserted, the mechanism is preferably arranged so as to be
adjustable in a direction transverse to the frame of the machine. The lower brake-
saddle or frame 3 rests, for this purpose, on a transverse bar 8 of uniform prismatic
form in cross-section, the pivot or hinge-pin 7 of the movable brake-arm 4 is
similarly adjustable in its seat or bearing and the double-armed lever 14, at the end
at which the thrust-rod 15 is supported, is formed with a broad part with a number
of notches or recesses in which the said thrust-rod 15 can engage.
In order to be able to weave backwards, a hand-lever 24 is pivotally attached to
the lower brake bearing or brake-saddle 3, by means of which hand-lever it is
possible to act on a special arm or lever 25 in connection with the double-armed
lever 14. By actuating the hand-lever 24, a nose or cam-shaped end 26 thereof is
pressed against the arm 25, so that the double-armed lever 14 raises the rod 13
and the movable brake-arm 4 connected therewith. The weaver can then turn
the warp-beam by hand as desired.
The above described mechanism can be arranged, as desired, either on one side
or on both sides of the loom.
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:-
1. An automatic let-off motion or warp-beam brake, comprising a rigidly
arranged brake-block and a pivotally mounted brake-block, which latter is pressed
downwards by a spring and is in connection, through suitable linkwork, with
pivoted arms carrying the lath or roller over which the warp or chain-threads
pass as they leave the warp-beam, these arms being likewise acted upon by springs,
in such a manner that, when the tension on the warp or chain-
threads is increased, the resultant movement of the arms carrying the said
lath or roller loosens or releases the pivoted brake-block and consequently the
tension of the chain or warp-threads always remains the same.
2. In a let-off motion or warp-beam brake such as is hereinbefore described,
the employment of two-armed levers, on which thrust-rods connected to the pivoted
or movable brake-arm and to the carrying-arms of the lath or roller, bear without
being connected thereto, so as to facilitate the removal of the movable brake-arm
which is loose in its bearing, substantially as, and for the purposes specified.
3. In a let-off motion or warp-beam brake such as is herein before described,
the employment of a hand-lever provided with a nose or cam which is capable of
acting on the linkwork in such a manner that the brake can be released by hand.
Dated this 18th day of March 1898.
D. YOUNG & Co.,
11 and 12, Southampton Buildings, London, W.C.,
Agents for the Applicant