Improvements in Rope Gearing.
Year: 1892

page_text: Date of Application, 10th Oct., 1892-Accepted, 25th Feb., 13°3
COMPLETE SPECIFICATION.
Improvements in Rope Gearing.
I, JOHN WALKER, of Lake Avenue, in the City of Cleveland, State of Ohio,
United States of America, Manufacturer, do hereby declare the nature of my
invention, and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
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This invention relates to certain improvements in that class of power-transmitting
mechanism in which a series of independent endless ropes are employed to convey
rotary motion from one drum to another. Such ropes are made of cotton, and the
whole arrangement is technically known as the cotton rope drive." It was
originally devised as a substitute for the belt in cotton-mills, as the vibration of the
belt was found to interfere with the uniformity in texture of the cloth produced.
The cotton-rope drive is now used in cable railways to transmit motion from a
grooved driver to a similarly-grooved driven drum and in place of toothed gearing.
The ropes are made slack to increase their traction. Before my present invention
the grooves were formed in the drums proper or in parts thereof which move in
unison with the shafts to which the drums are secured. Now were it possible to
make the cotton ropes of absolutely the same diameter throughout their length
and of the same weight per foot and of the same degree of hardness, so that they
would pass to exactly the same depth within the grooves, and also to splice the
whole series of ropes, so that their lengths would be precisely equal, all the ropes
would have a common tension and the whole driving strain would be accurately
and equally distributed among them; but such mechanical perfection cannot be
attained, and in the practical operation of the rope drive some of the ropes perform
nearly all the labor, the others being to a great extent inoperative as power-trans-
mitting devices; and as it is impossible to ascertain what proportion of the whole
labor is borne by each rope the only means of securing absolute safety has been to
use in each drive a much greater number of ropes than were theoretically required.
With my invention, as hereinafter described, a uniform strain is applied to all the
independent ropes, and in view of this their number may be reduced without.
incurring any danger of breakage.
In the further description of the said invention which follows reference is made
to the accompanying drawings, forming a part hereof, and in which-
Figure 1 is a side elevation of a driver and a driven drum connected by a series
of independent endless ropes in accordance with my invention.
Fig. 2 is a top or plan view of the same with some of the ropes removed to show
the drums.
Fig. 3 is an enlarged cross-section of two rings and a part of the drum proper,
together with two ropes.
Similar letters of reference indicate similar parts in all the figures.
In the said drawings, A represents the drums proper, and B independent rings
adapted to turn loosely and independently of each other on the smooth circum-
ference of the drums. These rings are grooved, as shown in the drawings-that
is to say, the grooves are reduced at the bottom to a width considerably less than
the diameter of the independent endless ropes, which are denoted by C. By this
means the comparatively soft ropes are forced tightly into the grooves and their
traction increased. As the strain on the ropes is equalized by the independent
circumferential adjustment of the grooved rings on the drums proper, a uniform
length of rope in the series is not essential, and the work of cutting and splicing
the ropes is therefore much simplified.
In Figure 1 the ropes are illustrated as of different lengths, which is always the
case even when a common length is aimed at.

page_text: In regard to the loose rings on the smooth drum, it is evident that the friction is
communicated to the surfaces between the rings and the drum. When no undue
strain is on the ropes, the rings move in unison with the drum, but when the
friction between the ropes and the grooves is not uniform, owing to slight differences
in the diameters of the ropes and the consequent increase or reduction in the length
of the portion of the ropes on the rings, some of the rings must inove a little faster
or a little slower than the others and the said rings will slide on the drums. If the
ropes were exactly uniform in diameter throughout their length, grooved drums.
without loose rings would answer the purpose, but all cotton ropes vary in size.
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 :-
The within-described improvement in rope drives consisting of a pair of drums,
each having a series of peripheral grooved rings adapted to turn independently of
each other and of its drum, combined with independent endless ropes rove around
said drums, each of said ropes resting in the grooves of oppositely-placed rings of
the drums, whereby a uniform strain is applied to said ropes, substantially as set
forth.
Dated the 26th da- of Condo-L. 1000
JOHN WALKER.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.