Improvements in or in the Manufacture of Woven Driving Belts.
Year: 1899

page_text: Date of Application, 9th Nov., 1899-Accepted, 27th Jan., 1900
COMPLETE SPECIFICATION.
Improvements in or in the Manufacture of Woven Driving Belts.
'A communication by THE MECH. TRIEBRIEMEN WEDEREI U. SEILFABRIK GUSTAV
KUNZ A. G., of Treuen, Saxony, in the Empire of Germany, Belt Manu-
facturers.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., Agent for Foreign Patent
Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street, Manchester, both in the
County of Lancaster, 118, New Street, Birmingham, in the County of Warwick,
and 322, High Holborn, in the County of Middlesex, Civil Engineer, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:-
The woven driving belts hitherto employed made of several layers of fabric, in
spite of the great advantages which they have ovor leather driving belts, always
still possess considerable defects. For instance it has been observed that the belts
on the running side, that is to say on the side with which they bear on the belt
pulleys, easily crack, and thus lose much of their durability.
As experience has shown, thin belts, when they have the necessary width for
transmitting the power, are less liable to crack on the running side than stouter
belts. Belts also which run over small pulleys crack more easily than those
which travel over large pulleys and the opinion has therefore gained ground from
many sides that the breakage is a consequence of the hardness of the belt. This
however is not the case as if a belt broke in consequence of its hardness the
fractures would become apparent on the outside of the belt and not on the inner
or running side.
The reason of the cracking lies therefore merely in the circumstance that the
warp threads of the outer side in bending or travelling over the belt pulleys,
especially when the diameter of the pulleys is small, do not yield or give suffi-
ciently, so that the warp threads on the running side are compressed or jammed
together. Seeing that in the travol of a belt over its belt pulley it clings firmly
to the said pulley, the warp threads which are compressed or jammed together
on the running side are always somewhat displaced and pushed back until they
come to the limit beyond which they cannot go, and they then here receive an
injury. If this displacement of the warp threads is not so apparent that it can
be seen by the naked eye the constant repetition of this process on the belts
passing over the belt pulleys is sufficient to destroy the warp threads at the place
where the compression takes place, and thereby cracks or tears very soon result.
If therefore a driving belt of two or more layers of webbing or fabric be cracked,
the reason of this cracking must merely be ascribed to the circumstance that the
warp threads lie too evenly between the weft threads in all parts of the belt, in
consequence of which, on running over the belt pulley an uneven strain of the
warp threads takes place, and thereby a destruction of the same is brought about.
The object of the present invention is to avoid this drawback, and this is
attained by the belt being so woven that the warp threads towards the outer sido

page_text: of the belt lie in the form of loops round the weft threads, and the weft threads
are stretched between the warp threads, whilst the warp threads lying nearest
to the running side are stretched between the weft threads, and the latter are
wound loop fashion round the warp threads. The result of this is that the warp
threads of the outer side, in bending round the pulley even when the same is of a
small size, are sufficiently yielding, so that no compression or displacement of
the warp threads on the running side can take place."
The weaving of such driving belts formed of two or more layers of webbing or
fabric in which the warp threads towards the outside lie loop fashion round the
weft threads, whilst the latter are stretched between the former, and the warp
threads on the other hand lying nearest to the running side are stretched
between the weft threads, and the latter lie loop fashion round the warp threads,
takes place in the following way, by the warp threads of the outer side being
slightly stretched, whilst the warp threads lying in proximity to the running side
are tauter, and then the weaving is effected in the ordinary manner according to
the desired pattern or sort of weaving required. This new method of weaving is
also applicable to all kinds of fabrics (linen, twill, or the like).
If the method of weaving driving belts hereinbefore described be modified by
inserting more weft in the lower layers of webbing than in the upper layers, a
driving helt is obtained, the warp threads of which are covered on the running
side, and consequently no wear can take place on these warp threads.
Such a method of weaving driving belts is shown in the accompanying drawings,
Figure 1 being a longitudinal section and Figure 2 a cross section a, a¹, all, a
being the warp threads of the separate layers of webbing. a is the layer of warp
threads lying nearest to the outside, and that lying nearest to the running
side or surface of the belt, that is to say the lowest layer of webbing. bare the
weft threads, the course of which may be easily seen in Figure 2.
In this drawing, the first weft threads go in a stretched condition first through
the warp threads of the upper shed and then, as pick 2 in a looped condition
round the warp threads of the lower shed and then in pick 3 they are again
stretched between the warp threads of the second layer of webbing or fabric, and
afterwards in pick 4 are again wound in loop form round the warp threads of
the under goods, and finally as pick 5 the movement of which is exactly the
same as picks 1 and 3, they are passed through the third layer of webbing, whilst
pick 6 passes through or traverses the lowest layer of webbing exactly as picks 2
and 4. The shuttle then commences its movement afresh. The warp threads of
the layers of webbing lie in such a way that a weaving together of the belt takes
place. Such a weaving together may of course be effected in various ways, but
may also be dispensed with.
In the method of weaving just described, more weft is introduced in the lower
layer of webbing than in the other layers of webbing, so that here the warp
threads are covered on the travelling or running side. Of course it may also be
so woven that an even distribution of the weft threads between the warp threads
takes place. Figure 3 is a longitudinal section and Figure 4 a cross section of a
woven belt in which less warp layers are employed. a indicates a warp thread
which forms a fabric only in the upper shed. is a warp thread which forms a
fabric in the upper and second layer of webbing. all is a warp thread which
forms a fabric alternately in the second and third layer of webbing, and al
forms the warp threads of the under layer of webbing, which again lie covered.
In this fabric or webbing a' and a form the foundation and also the binding
warp and a bindng together of the layers of webbing among themselves is obtained
by means of the alternate inter-engagement of the warp threads a' and a" of
the 1st, 2nd, and 3rd, layers of webbing.
From the cross section of this belt it can be seen that the travel of the weft
threads runs similarly to that described for Figure 2. In carrying the invention
into effect, two, three or more warp layers and any suitable method of binding
together may be employed.

page_text: If, the herein before described driving belts be made with the under layer of
warp thinner than the upper one, as shown in Figures 5 and 6 of the drawings.
a belt is formed which has a somewhat curved form, that is to say a domed form
is obtained which better fits on spherical belt pulleys. This doming or curving
is made on the side where the most warp is inserted, and it is attained without
the warp threads being made tauler at the edges than those of the centre, in
consequence of which the warp threads are exposed to an equal strain over the
whole width of the belt. The weft and warp threads of this modification of belt
lie and are passed like those of Figures 3 and 4, ouly the lower layer of webbing
is less stretched or strained.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to
me by my foreign correspondents, I declare that what I claim is:-
1. A woven driving belt in three or more layers of webbing or fabric charac-
terised by the warp threads being arranged to lie on the outer side in a strongly
waved form round the weft, and by the latter being stretched between the warp
threads, whilst the warp threads lying next the running side are stretched between
the weft threads, and the latter in a strongly waved form lie between the warp
threads for the purpose of an even tension of the warp threads when the belt is
running over the belt pulley substantially as herein before set forth.
2. A form of construction of the driving belt hereinbefore described, charac-
terised by a layer of webbing on the running side having a greater thickness
of weft than the outer layer of webbing for the purpose of covering and thus
protecting the warp threads on the running side of the belt, substantially as
described.
3. A form of construction of the driving helt hereinbefore described charac-
terised by the warp on the running side of the belt being made thinner than
the warp on the outer side of the belt with the object of imparting a domed or
curved shape to the belt, substantially as described.
Dated this 7th day of November 1899