Year: 1887

page_text: Date of Application, 23rd Mar., 1887.
Specification Accepted, 26th Apr., 1887.
[Communicated from abroad by WALLACE HARLOW DODGE, of Wishawaka, State of
Indiana, United States of America, Manufacturer.]
by Mi PPs of
I PHILIP MIDDLETON JUSTICE of 55 and 56 Chancery Lane in the County of
Middlesex, Fellow of the Institute of Patent Agents 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:-
It is well known to mechanical engineers that flat belts utilize a small part only of
their strength, in transmitting power because it is impossible to obtain an aimount
of traction comparable with the strength of the belt. It is also known that traction
increases with the width of the belt, and that with a specified belt power transmitted
increases with the velocity, but that, with an increase of speed there is a relative loss
in slip largely due to lubrication by air carried under the belt.
These engineering difficulties are overcome by the employment of a continuous
round belt, with multiple turns around the pulleys, for traction, and an automatic
slack taker to properly lead the belt and maintain a uniform tension on all the laboring
parts of it. It has been found to be impracticable to employ round belts, especially
those made from manilla rope, over pulleys whereof the diameter is less than forty
times the diameter of the belt, for the reason that a curve of less radius than that
named causes dangerous strains and displacement of the strands on the exterior of the
curve, and causes also rapid internal wearing out of the fibres. It is therefore
necessary sometimes to duplicate the working parts or ropes, and this I do by passing
the same rope repeatedly from the driver to the driven pulley until the number of

page_text: laboring parts is sufficient for the duty and said rope is caused to pass once around the
slack taking pulley to preserve a uniform tension throughout.
Rope belts, which are generally employed, will vary in length from hour to hour
from atmospheric causes and it is therefore necessary to employ a slack take up having
a long range of action and at the same time be provided with means for properly
leading the rope back upon the initial side of the pulley.
My invention relates entirely to the subject of transmission of power by a round
endless belt and it consists of several parts; first, the general system of obtaining
traction by multiple winds around the main and subsidiary pulley; second, the method
of avoiding one passage around both driver and driven pulley when the distance
between is considerable; third, in a system of double wind whereby a rope of small
diameter may be employed and the strain upon the splice is reduced one half, the
splice being always the weakest place in the rope and the part most rapidly worn out.
Referring to the drawings,
Fig. 1 is a perspective view showing my system in a general way.
Fig. 2 is a perspective view showing the second part of my improvement.
Fig. 3 is a perspective view showing the third part of my improvement.
Fig. 4 is a transverse section of the rim of a double wind pulley.
Fig. 5 is a perspective diagram illustrating the double wind of the rope.
Fig. 6 is an elevation illustrating my transmitting rope over guide pulleys to carry
it over an obstruction.
Fig. 7 is a plan of my rope splice.
A is the driving pulley, receiving motion and power from some convenient and
suitable source, as a steam or water motor. B is the driven pulley to which said
motion and power is to be transmitted by the rope belt C. The pulleys A and B are
simply typical members of a transmitting system; the source of power or its final
destination do not enter into contemplation.
V shaped peripheral grooves y are by preference made in one or both of said pulleys
to receive the belt C and keep it properly in place on said pulley. If the rope were
wrapped several times around the pulley to obtain additional traction, it would soon
creep out of proper position or would require a continuous application of force to
keep it in place; this is avoided, by using a supplemental pulley D and passing the
rope around the two until traction sufficient to prevent slip has been obtained. The
same arrangement of supplemental traction pulleys may be employed at both ends of
the system to ensure the delivery of all power received by the belt.
The changes of actual length produces by hygrometric changes in the atmosphere
are perfectly compensated by passing the rope over a proper slack taker at some point.
of its circuit, and this is generally most conveniently arranged by mounting a grooved
pulley E on a carriage F to which a spring, or preferably a gravitating weight. G is
applied. This imposes upon the whole length of the rope a uniform strain, and
therefore it maintains under all variations of the rope a substantially uniform tension.
If the rope passes over the pulley A or B more than once, it is evident if it
approaches the pulley, at its right hand end it will leave it at the left hand end and
must of necessity be returned again to the right hand end. My slack turning
pulley E is therefore placed on an axis oblique to the plane of the driving or driven
shaft, so that its edge at top may be in line with said right hand end of the
pulley (A or B) and its edge at bottom in line with said left hand end of the same so
that said pulley E will receive the rope in one vertical plane and deliver it in another.
If obstacles interpose between the driving and driven pulley leading pulleys h may
be employed to lead the ropes, and if the distance be great or the number of changes
in direction considerable it may be desirable to interpose two or more slack takers to
prevent an undue slackness on the return side of the rope.
When the distance between the driver and the driven pulley is considerable, and it
is necessary to pass the rope several times from one to another the weight of the rope
may impose considerable strain upon the shaft hanger and boxes, and I avoid a part
of that strain by using a snub pulley H as shown in Fig. 2, to change the direction of

page_text: the rope and lead it to the take up E without going again to the pulley at the opposite
end of the transmission, and by this means the journal bearings are relieved from the
strain due to the weight of the rope required to pass once from driver to driven pulley.
I have already pointed out the necessity for multiplying the laboring parts of the
rope in order to obtain the requisite tensile strength without an undesirably large
diameter of the rope, but however often the rope may pass around the driving and
driven pulley, the full measure of the strain upon it is at all times sustained by the
splice, and this has always heretofore been the point most likely to give way. When
the splice of the rope passes over the take up, it is evident the strain upon it is then
not shared by the other parts. To obviate whatever difficulty may accrue from this
cause I have devised a double wind whereby a smaller cord is employed and caused to
pass around the pulleys two or more times so that the labor of cach part is divided
between the two or three.
This mode of winding my rope upon the pulleys is shown in Figs. 3 and 5, and
consists in carrying the rope once through the whole wind, that is to say, back and
forth from driver to driven pulley so often as may be desired, it is then carried around
the snub pulley H, if one be used, and if not, then from the main driver or driven to
the take up E. If a single wind only were employed, the rope would then be led
back to the place of beginning and would there be spliced, but with the improvement
which I am now describing, a new wind is commenced and the rope again carried
around driver and driven as often as before and again around snub and take up and
the ends may then be spliced. With this arrangement it is apparent that as the splice
passes over the take up it will only bear one half the strain because it is always
accompanied by an unspliced part. If desired, the wind may be repeated still oftener,
but it is thought that a double wind is generally sufficient.
"
My method of splicing or joining the ends of the rope is as follows: I sometimes
merely whip the two ends and butt them together before putting on a cover K of lace
leather, which in itself has a tensile strength equal to the strength of the rope, but I
prefer to run the strands together after the manner of the sailors "long splice
without however tucking the ends of the strands. It is sufficient to secure them by
whipping. The cover K is long enough to extend beyond the points where the strands
are butted together, and should be well stretched before applying. Its ends are
slitted for a distance of four or five inches into six thongs, each trimmed narrower
toward its end. The rope is then laid longitudinally on the cover, and the edges
wrapped around it, and secured by pieces of twine at the base of the thongs, one
strand is then raised with a marlin spike and the first thong is wrapped around it
spirally, the next thong is then similarly wrapped around it, the two thongs will lay
more smoothly than would one of double the width.
The next strand is then raised and the two succeeding thongs are wrapped around
it in the same manner; and so on, at both ends of the cover.
By these means, a leather cover, having tensile strength equal to that of the rope is
applied by wrapping around the individual strands, and in that way the diameter of
the rope at the splice is not materially increased, and the passage around the pulleys
does not impose any extraordinary wear upon the fibres in consequence of an increased
diameter, and moreover the tensile strain is at that point mainly or wholly supported
by the cover.
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 correspondent I declare that what I claim is-
1. The herein described system of transmission of power by an endless round or
rope belt, wherein said belt is caused to pass around the driving and driven pulley and
supplemental pulleys to secure traction, and around an automatic combined take up
and leading pulley, whereby a single endless rope may be caused to pass around the
driving and the driven pulleys, two or more times, without creeping or slipping, and
with uniform tension.

page_text: 2. The transmitting rope C, pulleys A, B, and the slack take up pulley E combined
with a snub pulley H, placed between pulleys A, B, to take the slack and return it to
the pulley E, as and for the purpose set forth.
3. As an improvement in the devices for transmitting power, the pulleys A, B,
provided with the grooves g, and pulley E in combination with the rope C, wound
thereon double throughout, substantially as described, whereby a given strength is
attained with a smaller rope, and a divided strain on the splice, as set forth.
4. The pulleys A, B, the supplemental pulley D, the take up pulley E and the
rope C, combined with guide pulleys, h, whereby the transmitting rope may be
conducted around obstacles, as set forth.
5. In combination with the pulleys A, B, and the slack take up E, the rope C,
having its ends secured together with a cover K, of lace leather or other suitable
material, having its ends slitted into thongs, substantially as described and wound
around the strands separately, as set forth.