Year: 1899

page_text: Date of Application, 12th Dec., 1899
Complete Specification Left, 11th Sept., 1900-Accepted, 12th Dec., 1900
I, THOMAS FOSTER, Model Maker & Draughtsman, of The Owens College, Man-
chester, do hereby declare the nature of this invention to be as follows:
1
My invention relates to roller gearing where the pressure between the surfaces
of a system of rollers is taken up and balanced by an outer ring, or annular
wheel, the internal periphery of which forms one of the rolling surfaces.
The usual form of this apparatus consists of a central wheel in contact with
a set or sets of intermediate or transmission rollers the whole surrounded by
an annular wheel.
A set of transmission rollers may consist of two or more working on studs
fixed to the framework and arranged at suitable distances from each other, a set
consisting of three is preferable, but there may be two or more such sets, the
first set working upon the internal wheel whilst those of the outer set bear
Each roller
against the annular wheel and the members of the next inner set.
may be either plain or compound, a compound roller receiving its motion on a
part having a certain diameter and giving it off from a part having a different
diameter.
When it is not necessary for the axis of the driver and driven to coincide, then
any one of the rollers, including the inner central wheel and the outer annular
wheel, may, by being suitably connected, become either the driver or the
driven, or one of these may be the driver and all the remainder driven, and the
several rollers of a set may be of different diameters.
For the purpose of throwing the rollers in and out of gear, I use, in one
arrangement, two or more sets of transmission rollers so arranged, that when in
gear, the axis of the corresponding rollers of each set shall be in the same or
nearly the same radial planes; to throw them out of gear, the rollers of one
set are made to move out of those planes, and therefore out of contact with one
or other surface. An allowance for wear and a margin for increasing the pres-
sure between the rolling surfaces my in this case be obtained by making the
In another
rollers slightly too large to be put into perfectly radial lines.
arrangement where only one set of transmission rollers is used, I make the rollers
of different diameters, which has the effect of making the space between the
central wheel and the inner periphery of the outer ring eccentric, and by moving
one or more rollers from a position where they press against both inner and
outer wheels into a position where the space is greater, then the rolling contact
will be broken, and restored when the rollers are moved back again.
Another principle of applying pressure and compensating for wear is to use
balls between the outer and inner wheels instead of cylindrical rollers the balls
being adjusted to the required tightness by the usual method of setting ball
bearings. These balls must be prevented from travelling round with the wheels,
by rollers working on studs the balls revolving against the rollers.

page_text: In the arrangements here described either the studs on which the transmission
rollers work or the outer wheel may form the fulcrum for the turning effort of
the whole train of mechanism.
Datal 1
1011
71
tion Gearing.
I, THOMAS FOSTER, of The Owens College, Manchester, in the County of
Lancaster, Technical Instructor, 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:-
My invention relates to roller friction gearing where the pressure between the
surfaces of a system of rollers is taken up and balanced by an outer ring, or
annular wheel, the internal periphery of which forms one of the rolling surfaces.
The object of this invention is to provide an extremely simple and effective
friction gearing suitable for reduction or increase of speed.
For the purpose of making the invention clear it will be described with refer-
ence to the accompanying drawings in which
Fig. 1 is an end view of one form of gearing.
Fig. 2 is a sectional plan through same on line A A.
Fig. 3 is a view on a reduced scale of a motor and the gearing applied thereto.
Fig. 4 is a similar view to Fig. 1 but on a smaller scale to show a modification.
Fig. 5 is a section on line B B of Fig. 4.
Fig. 6 is a similar view to Fig. 1 to illustrate a further modification.
In Figs. 1 and 2 there is shown a simple form of friction gearing in which a
is an outer annular ring or wheel which may form part of a pulley for a belt
or be connected by coupling to a suitable shaft. is a shaft, or a roller or disc
carried by a suitable shaft (which is included in the term shaft hereafter) and
cde are transmission rollers or discs all of the parts having parallel friction
surfaces. The rollers c and e are carried on studs w fixed in a frame f which may
be the end plate of a motor or be otherwise suitably held, while the roller
is entirely loose and free to move around the central shaft or roller b though
it is preferably provided with a pin g secured in the end plate or frame f
which passes into a central opening of same to limit its movement and prevent
its falling into a position where it would be out of contact with the driving part.
To allow of sufficient movement this roller is usually made ring shaped as shown.
It will be seen that the roller c is of a larger diameter than rollers d, e, but
the loose roller may be of the larger diameter or two rollers may be large and
one small, the object being to enable the loose roller to wedge between the
central shaft or roller and the interior surface of the annular ring a when the
__central shaft or roller is rotating in one direction though it is loosened so that
no driving takes place when the shaft rotates in the opposite direction. This
ring a in the arrangement shown forms a pulley and is grooved internally and
carries a dust or enclosing plates. Each stud carries a perforated sleeve r
and is also preferably provided with a passage i connected with a passage j
in the end plate f and through which oil may be supplied to a recess in the
wheels c, e, such recess being preferably filled with fibrous material to hold the
oil. The motor shaft is preferably provided with a hardened steel sleeve k
secured thereto and such shaft passes through a large opening in the end plate f
so that it may have its only bearing at this end upon the rollers c, d, e, which

page_text: thus form a roller bearing for said shaft. The shaft carries the armature and
has the usual bearing at the other end as shown at t in Fig. 3. By reason of
the different sizes of the rollers c, d, e, the motor shaft is not central with
the pulley or ring a though it drives same in a circular path.
It will be seen that in the case of a high speed motor a reduction gearing
is thus provided of a very simple type, the action consisting in the shaft when
rotating in the direction of the arrow forcing the loose roller d into the smaller
space between it and the ring or pulley a so that such roller commences to drive
as it grips the two and thus causes the other rollers to transmit motion also.
With this arrangement no driving can take place when the shaft rotates in the
opposite direction as it would tend to move the loose roller into the larger space
and would therefore release all pressure on same.
If driving is desired in both directions as may be the case for traction work
and other purposes two or more loose rollers are employed as shown in Figs. 4
and 5 where the arrangement consists of two rings or rollers d, d in this case of
larger size than the rollers c, e which are arranged so as to travel into the smaller
space when the shaft 6 drives in one direction and a single roller m of the same
diameter as, and situated between the rollers d, d adapted to fall into the smaller
space when the shaft drives in the other direction so that either rollers d, d or m
do the gripping according to the direction in which the shaft rotates. The
pins g g act as in the case of the other pin g to prevent the rollers from getting
out of the right position for gripping. These loose rollers may be arranged
as shown, that is, one wide one m in the middle to grip in one direction and two
narrow ones d d at the two sides to grip in the opposite direction or there may
be simply two of them, one for each direction set side by side each half the width
of the groove or interior of the ring or pulley a.
In the arrangement shown in Figs. 1 and 2 one set of three friction transmis-
sion rollers is shown but more than one may be employed. For instance they
may be arranged in two sets of three as shown in Fig. 6 in radial lines front
the centre shaft or roller 6 the first set consisting of a series of three rollers oo o
of equal size which bear against the shaft or roller b and the second set of
rollers c d e as in Fig. 1 each of such rollers bearing on a roller o and on the ring
or pulley a the loose roller d travelling into the smaller space caused by the
increased size of roller c when the driving takes place in that direction.
It will be understood that by making one or more of the rollers of larger size
than the others the wear is enabled to be taken up by the loose roller or rollers
and the necessary pressure is obtained between all the rolling surfaces to keep
them in the desired frictional contact.
In place of being formed as a pulley adapted to take a belt the ring a may
be formed as a spur or bevel gearing or as stated it may form part of a coupling
connected to the driven shaft or as will be readily understood in place of the
roller or shaft b doing the driving it may be the driven part, the power being
applied to the ring a.
The end plate for carrier or support for the studs w and ping of the rollers
may be arranged to be adjustable in the plane of rotation so that the rollers
supporting the interior smaller revolving part or shaft can be placed in the
most favorable position relatively to the resultant of the force of gravity and any
other external force such as the pull of a driving belt.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is :
In frictional rotary motion transmitting gears, of the balanced pressure type,
in which the cylindrical driving and driven parts are eccentrically disposed one
within the other, with limited freedom of relative motion in the plane of their
rotation and their angular velocities, though inversely proportional to their

page_text: radii, are rendered interdependent by intervening wheels or rollers in contact
with them both.
The use of an intervening motion transmitting roller, which is free to revolve
about its own centre and be out of driving contact and also capable of movement
on the driven part in the direction towards the point at which the radial distance
between the driving and driven parts is a minimum, until it reaches a position
where, owing to its wedgelike action, a radial pressure proportional to the turning
effort is exerted between the contiguous surfaces of the driving and driven
parts and the intervening wheels or rollers, the friction created by which pres-
sure is great enough to resist the tendency of the surfaces to slip one upon the
other, under the influence of the tangential effort applied at their point of contact.
Dated this 11th day of September 1900.
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London,
Chartered Patent Agent,
For the Applicant.
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London,
Chartered Patent Agent,
For the Applicant.