Improvements in Friction Gearing.
Year: 1890

page_text: Date of Application, 22nd Apr., 1890-Accepted, 24th May, 1890
COMPLETE SPECIFICATION.
Improvements in Friction Gearing.
I, GEORGE FRANK EVANS of Somerville, County of Middlesex, State of
Massachusetts, United States of America, Mechanic, 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 the transmission of power, the essential characteristic of
which consists in running a loose belt between two pulleys, one of which is encircled
by said belt instead of by the usual way of encircling both pulleys with a belt.
In said mechanism for transmitting power, it has been found impracticable to run
wide belts between the pulleys, since the circumference or length of the belt, is not
the same upon the edges, changes occurring owing to inequalities in the consistency,
as likewise in the wear, some parts wearing more than others, or stretching more than
others. As a consequence, the belt is inclined to run obliquely to the longitudinal
axis of the shaft which carries the pulleys, in lieu of 'at right angles thereto, and slip
occurs upon the long side of the belt.
The purpose of my invention is to endeavour to obviate such action and to direct a
belt, or belts, at right angles to the longitudinal axis of the shafts, which rotate the
pulleys. To effect such purpose, I provide one of the pulleys with flanges, one or both
removable, and place about such pulleys an endless band or belt, or series of bands or
belts, all preferably being of the same length, width and thickness, each belt being of
a length larger than the circumference of the body of the pulley but less than that of
the flanges, hence the latter, one or both, are made removable for purposes of replacing
or taking off said belts.
By providing a series of belts any slight variance in the lengths of the individual
belts for any cause whatsoever, will not affect the action or speed of any other of the
series and each belt is free to run independently at its own rate of speed or that pro-
duced by its own length, thus no slip occurs and further by guidance of the flanges
each belt will naturally travel towards the shafts at right angles and without oblique
shifting.
The drawings represent in
Fig. 1a front elevation of mechanism, embodying my invention.
Fig. 2 is a side elevation, one of the flanges being removed.
Fig. 3 is a section of the flanged pulley, and belts and removable flanges a, a.
Fig. 4 represents my invention applied to a dynamo, the latter being shown in
perspective while the driven pulley is represented only in part.
In said drawings, A represents one shaft, preferably the driven; B represents the
other shaft; upon which are mounted, respectively, two straight-faced pulleys C, D,
sections of cylinders cut transversely. The driven pulley is provided with
flanges a, a, both being shown removable; about said pulley are arranged a series of
parallel bands b, b, preferably of the same length, width and thickness. Since the
length of such belts is less than the circumference of the flanges one of these is
removed to permit belts, as many as may be desired, to be slipped about said pulley
which they loosely encircle. The flange is then replaced, proper pressure is brought
to bear upon the belts by the pulleys and upon rotation of the driver the driven pulley
is set in motion.
As it is frequently desired to start or stop the driven pulley, its shaft and the
mechanism actuated thereby, as likewise to increase or diminish the pressure upon the
endless bands, I have shown in Fig. 4 a device by which the driven pulley is caused
to approach or recede from the driver, it being understood that said pulleys are non-
contiguous, but are adapted to grip the endless bands, which loosely encircle one, and
pass between said pulleys.
This adjusting device is here shown as applicable to electric generators and consists
D

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of a heavy, permanently fixed base E, provided with one or more screws d, revolubly
secured to standard F, movable in guides upon the base, said standards being fitted
with journals in which the shaft B of the driven pulley is mounted.
By such an arrangement of a series of endless bands it is evident that the power
transmitted may be increased or diminished upon the same pair of pulleys by simply
adding to the number of belts or by removing some of them, while as each belt is
travelling independently no slip occurs, as heretofore, due to the differences in the
rate of speed between the two sides of a wide belt resulting from the variation in the
length of such sides.
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 :
Q
1. The mechanism for transmission of power between two lines of shafting, com-
posed of two shafts, two pulleys thereupon, one of which is flanged, and a series of
endless bands, which loosely encircle the flanged pulley and are adapted to travel
independently between and be gripped by said pulleys, the latter non-contiguous,
substantially as herein described.
2. The combination with two lines of shafting, two pulleys thereupon-the driver
and the driven one being provided with flanges one or both removable, of a series of
endless parallel bands which loosely encircle the flanged pulley, but smaller in circum-
ference than said flanges and adapted to pass between and be gripped by said pulleys,
all substantially as set forth and stated.
3. In mechanism for providing rotary movement between two lines of shafting, the
combination with a shaft and a pulley thereupon, of a second shaft having a flanged
pulley, a series of endless bands loosely thereabouts, the two pulleys being non-
contiguous, and means whereby one is adapted to approach or recede from the other,
substantially as and for purposes lierein specified.
4. The mechanism for transmitting power between two lines of shafting consisting
of two shafts, two pulleys respectively thereupon, one of which is provided with
removable flanges and an endless band which loosely encircles the flanged pulley, but
smaller in circumference than said flanges and adapted to pass between and be gripped
by said pulleys, substantially as stated.
Dated this Third day of March 1890.