An Improved Process for Winding Warp Threads upon Beams and Weaving them from Beams at relatively different Speeds.
Year: 1898

page_text: Date of Application, 7th Nov., 1898-Accepted, 14th Oct., 1899
An Improved Process for Winding Warp Threads upon Beams and
Weaving them from Beams at relatively different Speeds.
I, OSWALD HOFFMANN, of Neugersdorf, in the Kingdom of Saxony, German Empire,
Manufacturer, 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:-
This invention relates to an improved process for winding warp-threads upon beams-
and weaving them from beams at relatively different speeds, and has for its object to
remove certain disadvantages hitherto connected with such processes.
Hitherto, when fabrics woven from warp threads travelling or fed at relatively
different speeds were produced, the beams were caused to travel at different speeds by
means of brakes applied to the beams, with the object of producing a different tension
in the threads, or, for the same purpose, feeding rollers were employed near the
beams.
The disadvantage of the first system mentioned was found to be the exact regula-
tion of the relative tensions of the threads, when inserting the picks, also in the
withdrawal of defective picks, and further in the correct rewinding of the
already unwound parts of the threads; whilst the second mentioned system possesses
the disadvantage, that the construction was unnecessarily complicated and thus the
attendance to the machine rendered more difficult.
I have with a view of obviating the above disadvantages designed the following
method, which I show in general outline in the accompanying drawings Figures 1-4.
By my improved process the winding and unwinding of the warp threads takes
place at a uniform relative speed ratio the beans being connected together by
gearing or otherwise while the warp threads are wound on beams of different
diameters.
If the diameters of the beams and the gearing are properly chosen then from
beginning to end in weaving always proportional lengths of threads will be unwound.
It is then necessary to brake one beam only as, owing to the beams being connected,
the tension will be transmitted to the other beam.
The arrangement also works well in withdrawing defective picks as it is only
necessary to apply tension to one warp the other warp thread immediately receiving
the proper tension owing to the connection between the two beams.
The arrangement for two beams is shown in Figs. 1 and 2.
On beams & and e of different sizes are wound warp threads or chains i and r in
such a manner that the diameters of the empty beams are proportional to the
diameters of the wound beams, as shewn in Fig. 2 by dotted lines meeting at l.
The beams d and e are geared together for instance by chain wheels f and g
connected by a chain h.
The threads are drawn off, when weaving, towards m in the directions shewn by
the arrows in Figure 2.
In calculating the diameters of the beams and the transmission gear the following
equations may be used, which are arrived at from the consideration that to obtain
a constant equal travel of the warps the cross-sectional area must be proportional
CD
077

page_text: to the square of the radii. If now the volumes of both warp threads, which are
in most cases, proportional to their weight, are represented by G and G₁ and the
corresponding radii of the beams by R and R₁ then the equation
In cases where fractions of teeth result the circumference and width of the beams
must be altered so as to obtain a whole number of teeth.
In order that in weaving the warps may be used up simultaneously it is pre-
ferable to control the number of revolutions in winding the several threads or to
wind the warps by means of the same gearing to be used in weaving.
The small differences there may be owing to inequalities in the material can be
adjusted by the tension given to the threads.
In those cases where one warp represents only a small bulk of material as com-
pared with another it is preferable to wind both threads on one beam only having
different diameters, the longer thread being wound on that portion of the beam
having the greater diameter while the shorter thread is wound on that portion of
the beam which has the lesser diameter see Figures 3 and 4.
In order to obtain the larger diameter I preferably pass rings over the empty
beam (.
To obtain a constant ratio between the travelling speeds of the warps the radii of
the empty beams must be proportional to the lengths of the threads.
If Land L, represent the lengths of the respective warps then

page_text: preferably use a distributing rail c which may either be suitably curved or provided
with points.
Instead of providing the beam with rings bor making a solid beam of the required
different diameters it may suffice to lap the beam with cloth or the like to attain the
correct diameter.
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
A process for weaving fabrics in which the various warp threads are wound on
beams of different diameters and corresponding lengths said beams being con-
nected or geared together so that the unwinding speeds of the various warp
threads maintain the required ratio to each other substantially as described.
Dated this 7th day of November 1898
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.

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