IMPROVEMENTS IN APPARATUS FOR TRANSMITTING MOTION
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clarke at the
Office of the Commissioners of Patents on the 22nd January 1881. A com-
munication from abroad by Stephen Dennis and Antonio Samper, both of
the United States of Colombia, South America, and at present of Paris,
France.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN APPARATUS FOR TRANSMITTING
MOTION." [A communication from abroad by Stephen Dennis and Antonio Samper,
both of the United States of Colombia, South America, and at present of Paris,
France.]
This Invention relates to improvements on the Invention the subject of former
Letters Patent, dated 16th July 1879, as a communication from the said Stephen
Dennis, and Antonio Samper, and Julio Valenzuela. As described in the Specification
filed in pursuance of the said Letters Patent, the Invention had for its object the
transmission of motion by means of bands, ropes, or chains, wound spirally on
drums or surfaces receiving rotary motion.
The accompanying Sheet of Drawings illustrate examples of modifications of the
aforesaid Invention provided with the improvements which form the subject of the
present Invention. Figures 1, 2, 3, 4, 5, 6, and 7 show arrangements of the
mechanism in which an endless cord or band is employed; Figure 8 the arrangement
in which a band with free ends is used; Figure 9 shows the original guide roller;
Figures 10, 11, and 12 show three modifications of the guide roller; Figure 13
represents the least amount of conicality that should be given to the drums or
pullies when the guide rollers, shown in Figure 11, are used, in order that the
mechanism shall work in the most perfect manner possible.
In the former Patent above mentioned, the band passed under the guide roller
between it and the drum or pulley, with which it remained always in contact, the
coils being separated by the spaces between the grooves of the guide roller, but it
will be observed in the accompanying Drawing that the band is now applied in
spiral coils either open or separated from one another, or not so separated, as in
Figures 4 and 5. But when the coils of the band are separated they are passed
over the guide roller, as in Figures 1, 2, and 3. The band may thus be wound
either in close or open coils, and either over or under the grooved guide rollers.
The guide rollers may also be placed laterally to the band as hereafter described.

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Figures 1, 2, 3, show the original form of guide roller a, as before stated, the
band being so applied so as to pass over the said guide rollers.
Figure 9 shows the guide roller alone.
Figure 10 shows a modification of the guide roller a, in which the grooves are
reduced to a single one, thereby permitting the band to be wound in close coils
provided it passes over the guide roller, and enabling the number of coils on the
pulleys or drums to be increased as represented at one side of Figure 7.
The guide rollers, shown in Figures 11 and 12, are in reality two different
arrangements of the same modification, their use depending on the mode of winding
the band. When wound in open coils the guide rollers are short tubes turning
loose on studs and embracing the several coils laterally, as shown in Figure 7; in
the other case, when the band is wound in close coils, but a single loose wheel & is
employed, as shown in Figures 4, 5, 6, and 8.
In order to transmit motion with the band passing over one of the grooved
guide rollers, as in Figures 1, 2, and 3, a slight degree of tension should be given to
the band, and for this purpose a convenient tension device is shown applied to the
arms of the frames carrying the guide roller in Figure 1. A single tension device
is sufficient for each band even if it be applied to many machines. The said
tension diminishes if the adhesion of the band be increased. By this means also all
sorts of pulleys may be used, such as straight, convex, conical, fluted, grooved, &c.,
and they may be made of wood.
In order to transmit motion when guide rollers, Figures 11 and 12, are used, if
the band is not exactly the proper length, the tension device above mentioned must
be applied, but in order not to lose power, only the one slack coil of the band is
taken up, as shown in Figure 5.
The guide rollers shown in Figures 7 and 12, consisting of small loose tubes and
the single guide wheel, Figures 4 and 11, may be applied in connection with
straight smooth pulleys or coned pulleys. Figures 13 shows graphically the rule
for finding the angle of the least amount of conicality that can be given to the
pulleys if they are to be made conical. The horizontal A, B, = the width of the
face of the pulley, the vertical B, C, the diameter of the band when wound in
close spirals or the width of the groove in the guide roller when wound in open
coils; the hypothenuse A, C, represents the cone, that is to say, the inclination to be
given to the pulley face in order that it shall work perfectly. A greater degree of
conicality may also be given to the pulley.
In order to apply the guide rollers shown in Figure 12 the pulleys should be
very conical and the spiral coils very open, in order to permit of increasing the
size of the tubes forming the guide rollers. The diameter of the latter may also be
increased by withdrawing the studs which form their axis.
;
When the single guide wheel, shown in Figures 4, 5, and 11, is used, the coils of
the band are quite close together, as shown in the Drawing.
When conical pullies are employed, as shown in Figure 5, the cones should be
reversed the one to the other, and in winding the band the leading part should be
on the larger diameter of the cone, as represented in Figure 5, in order that the
band shall be maintained in position. The pulleys should be rather wide in order
that the band shall not run off when the power is stopped in case the band is slack;
or the pulleys should have a flange at the smaller ends.
The band will work without a tension device if it is exact length, or with a small
tension device f if it is not exact. When the small lateral guide rollers, shown in
Figure 12, are used, the band may be either tight or slack.
When the band is wound tight round the pulleys, as is the case when the guide
rollers, Figures 11 and 12, are used, tension may be applied to the band without
any loss of power; and when the guide rollers, Figures 9 and 10, are used by
passing the band over them, loss of power is avoided by winding the band, as
shown in Figures 1 and 2.
Bands or ropes of all kinds may be employed, including iron-wire ropes, and two
or more may be used together, the coils being two or more in number, and

page_text: differently arranged, according to the circumstances of the case. One or several
guide rollers may be used, and they may be differently arranged with regard to
the pulleys except in the case of the single guide wheels. In the latter case
(Figures 4 and 5) that of the driving pulley may be advanced a fourth of its
circumference from the point where the band leaves the pulley, whilst the other
should be placed at from 1/2 to 3/4th the circumference from the corresponding
point. The guide rollers may be mounted on the pulley shafts or at a distance
from said shafts; in the first case they must be so mounted as to remain stationary
in position.
In short, there are many ways of winding the bands and of applying the guide
rollers, all the modes of applying the Invention not being illustrated here.
The term "bands or ropes" when used herein is intended also to comprehend a
chain.
From what has been above explained it follows that by employing the set of
small lateral guide rollers, shown in Figure 12, the transmission of the power or
motion may be interrupted without the use of loose pulleys by employing a loose
band and a tension device, which may be applied to act on the band or not at will;
in other words, it is the band which is made loose instead of the pulley.
The right is reserved of using all kinds of bands or ropes, whether endless or
with free ends. Figure 8 shows an arrangement of mechanism in which the rope
or band has two free ends, and according to this Figure the one end Z ascends
whilst the other descends. By employing the grooved guide rollers or the series of
small lateral guide rollers (Figure 12) one only required, whereas if a different
kind of guide roller is employed two would be required to each pulley to enable
the motion to be reversed. This arrangement of rope with free ends is applicable
in numerous cases; for example, in loading and unloading vessels, in working
mines, and other analogous situations, whereby an economy of time, space, and
power are obtained. The weight of the rope and lifting hook answer the purpose
of the small tension device necessary when the rope passes over the guide roller,
and consequently the rope must have a considerable number of coils in order to
avoid the use of a heavy rope.
Figure 6 shows the mode of transmitting motion from a horizontal to a vertical
shaft.
In all the Figures of the Drawing x is the driving and y the driven pulley;
2, the band or rope for transmitting the power; a, c, d, the guide rollers; e, the
arms of the frame in which these rollers are mounted; f, the tension devices
provided with screws h; i, the spindles of the guide rollers. In Figure 8 k is the
frame of the windlass; p, the drum; and m, and n the two standing pulleys over
which the falls of the rope pass.