IMPROVEMENTS IN FRICTION GEARING
Year: 1883

page_text: LETTERS PATENT to William Edward Ayrton, Professor of Technical Physics,
Fellow of the Royal Society and John Perry, Professor of Mechanical
Engineering & Applied Mathematics in the City & Guilds of London
Technical College Finsbury in the County of Middlesex for an Invention of
IMPROVEMENTS IN FRICTION GEARING
PROVISIONAL SPECIFICATION left by the said William Edward Ayrton and
John Perry at the Office of the Commissioners of Patents on the 21st June
1883.
WILLIAM EDWARD AYRTON Professor of Technical Physics, Fellow of the
Royal Society, and JOHN PERRY, Professor of Mechanical Engineering and
Applied Mathematics in the City & Guilds of Loudon Technical College Finsbury
in the County of Middlesex "IMPROVEMENTS IN FRICTION GEARING'
"
Our invention relates to methods of driving from one shaft to another and is of
especial importance, when the angular velocities of these shafts are very different.
It has been primarily designed for driving ordinary machinery, from the rotating
spindle of an electro-motor or other quick-moving engine, or for driving Dynamo-
machines, and other quick-moving machines from ordinary shafting, that is either
in the great reduction of speed, or in the great increase of speed
In the first part of our invention we drive from the spindle M fig 1 which has
great velocity, there being fixed at the end of this spindle, a hard metal bush P.
Another roller Q lies against P, and both rollers are held between the two
flanges S and T, on the rim of the large wheel whose axis is F, Various means
may be employed to produce considerable pressure between P Q and the flanges of
the large wheel In some cases we bevel the rims of P Q and of the flanges, as
shown in figure 2 so that there may be no rubbing, and that there may be true
rolling on all the surfaces in contact Sometimes as in figure 3 one or other of
the rollers has an annular projection for the same purpose, and this method we
ID 1.1

page_text: prefer to employ when the metal is hard enough for the purpose.
bearing in a slot
has its
To produce the gripping pressure we generally allow the roller Q to be pressed
in the direction of its axis by means of a spring, Q being fitted to its spindle on a
feather, and in this case we prefer to have the two flanges S and T on the large
wheel somewhat flexible, so that the grip may be more elastic. Sometimes as is
shown in figures 4 and 15 we have a ring G or K attached to the flange by springs
which can be adjusted in position by means of bolts. In all the other parts of
our invention we may employ any of these methods of producing the gripping
pressure
In figures 5 and 12 we show a rail or rod or rope R inserted between the
gripping wheels P and Q. This part of our invention we employ for the purpose
of propelling a vehicle, on which the large wheel STF and the motor and gripping
wheels are fixed along the rope, rod, or rail R in teipherage and in other
transmission of goods and passengers by means of electricity
Instead of the method of figure 2 we may employ a method shown in figure 6.
And in cases where the shaft M is not at right angles to the shaft F, wo may
.employ the method shown in figure 7
In all these cases either the roller P or the roller Q may be the roller which is
attached to the motor shaft
In figure 8 the motor spindle and the axes of the driven wheel are parallel to
one another, and it is seen that by making the diameter of the part of the
roller which rolls on the inner flange T smaller than the part of Q which is in
contact with P, it is possible to get true rolling without slipping
Figure 9 and 10 show the nature of this method of driving when the roller Q
becomes large in comparison with P
.
In figure 11 a slight modification of the method is shown, where it is the
roller P, which is smaller in diameter at the place where the uniform roller Q
touches it
The second part of our invention is a method of driving from the motor
spindle M of figuro 13. The bush P is gripped between three rollers Q'Q² Q³ and
these rollers are centred on the frame G fastened to the shaft F. Tho rollers are
gripped on their outside circumference by the internal rim of a wheel, ring or
tub HH, the gripping pressure being produced either as shown in the figure, by
the movable ring J J which is fastened by springs to the outer ring L L., the
outer ring being attached to the frame or tub or wheel by the adjustable bolt K,
or it may be produced by making the part P conical and adjustable in position; or
in other ways, the essential difference between these methods of gearing and some
of those lately invented by Prof Fleeming Jenkin, being due to our fixing the
external part H and obtaining motion from the frame of pulleys GQ. The fixing
of Hallows us to dispense with extra bearings for carrying the shafts. Of course
instead of employing the three pulleys Q, we may employ two or any higher number.
In figure 14 we show a case in which a much greater reduction in speed is
obtainable, the fixed tub or wheel or frame gripping the outside of the rollers Q,
on their spindles, or smaller drums attached to their spindles, on the two sides of
the pulleys The fixed frame H may now be in two parts or be made as one large
casting so as to embrace the pulleys.
It will be observed that in this case since the frame with the pulleys Q, rotates,
and we allow the spindles of the pulleys to ride in radial slots on the frame, we are
able to take advantage of the centrifugal force due to the rotation of the pulleys
and this will enable us to have a greater pressure at the places A and B, thau at
the places C and D without such a condition being produced the gearing would be
useless. The reduction of speed in this case is not in proportion to the diameters
of the outer and inner rolling surfaces, as it would be if the frame G were fixed,
but is that ratio plus unity
The third part of our invention relates to the use of friction-gearing in a manner

page_text: which is analogous to the well known differential gearing, when spur or bevel
wheels are used, In the cases bithorto considered we have been able to balance
the very great pressures which usually act at the bearings of shafts in friction
gearing, and this balancing of pressures we also effect in our differential gearing
In figure 16 M is a motor spindle whoso bearing is in the fixed frame A A,
and P is a roller fastened to the end of the motor spindle. The frame L carries
two or more rollers Q symmetrically placed, and these rollers are firmly gripped
between P inside, and the fixed tub A A and the moveable tub R R outside.
RR is keyed to the shaft F which we wish to drive. The diameters of the
tubs A A and of R R, and therefore the diameters of the parts of the rollers Q.
which roll inside these tubs, differ by a comparatively small amount, and tho
smaller this difference the greater the reduction of speed from M to F. The
bearings of the rollers Q ride in radial slots in the frames L, and the gripping
pressures may be produced in various ways, for example, by slightly tapering the
rolling surfaces and employing springs to give to the rollers a longitudinal motion
In figure 17 it is the frame L, carrying the bearings of the rollers Q in radial
slots as before, which rotates with the motor spindle The driven shaft F rotates
slowly with the tub R and the tub A is fixed. The rollers Q are gripped between
the tubs on the outside, and the central piece P by any suitable methods of
producing the necessary pressure. and it is the small difference of the internal
diameters of the tubs A and R in comparison with the diameters themselves which
enables us to obtain a very great reduction of speed, For botter balancing of
pressures the loose roller P may have a neck as shown in figure 17. instead of being
simply cylindric as shown in figure 16.
Figure 18 does not differ materially in method from figure 16, .
In figure 19 we have the same arrangement as in figure 17 with the central part
left out.
It is employed in cases where a dependence, may be placed on tho
constancy of the speed at which we wish to drive, so that the centrifugal force of
the rotating rollers Q1Q" may be sufficient to produce the necessary gripping
pressures on the insides of the tubs R and A
It is obvious that in cases where our arrangements are so strong that we need
not fear a want of rigidity in the framework we may employ one roller Q but we
prefer to use two or more symmetrically placed so that the stresses in the frame-
work shall be balanced.
In figure 20 if one of the rollers P¹ or P" is keyed to the spindle M and the
frame L is loose wo have the same method as that shown in figuro 16 P being
divided into two parts. This figure 20 is also the method of figure 17 if it is the
frame L which is keyed to the spindle M the rollers P' and P" being loose.
To produce the gripping pressures we may as already described have any of the
rollers conical or as shown in figure 3, employing a spring acting longitudinally
using the principle of the wedge. Or again the method may be that shown in
figure 13., where a wedge-shaped ring on any of the tubs is acted on by springs.
Again the method may be that of figure 15 where the ring K is pressed out against
a roller by means of a continuous spring all round the flange T, or a set of springs.
Again the method may be a modification of the gravitation grip shown in figuro 12,
gripping a pulley instead of a rail.
In figure 21 the tub A A has a ring A C B which encloses the spring B whose
coils are of large diameter between itself and A. It is on the internal surface of
this spring B that the rollers roll and the tightening of this spring in the
direction CF causes its coils to tend to become smaller in diameter thus producing
the requisite gripping pressure on the rollers Q. It is the wedge like shape of the
ring ACB which produces this effect. When we have no wedge-shaped backing
to the spring it is an elongation of the spring in a direction parallel to F C which
gives the grip.
Figure 22 shows this method applied to a roller P on the spindle M. When the
nuts F and F' are tightened the spiral spring B is made to expand on the cone C

page_text: .
and grip the rollers QQ. When there is no cone touching the inside of the spring,
the natural tendency of the coils of the spring to expand when the spring is
shortened is sufficient to produce the grip
In figure 23 the coned collars C C slide freely on a feather on the spindle M
A spiral spring B presses the collars apart and causes them to grip the
rollers Q¹¹ Q¹
In figure 24 the collars C C are drawn together by the spring B and thus grip
the rollers Q
The
Fig 25 shows the method of fig 13 as applied to two tubs at once.
tightening of the wedge-shaped ring J J causes the pulleys Q to bear on both the
tub A and the tub B.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Edward Ayrton and John Perry in the Great Seal Patent
Office on the 21st December 1883.
WILLIAM EDWARD AYRTON, Professor of Technical Physics, Fellow of the
Royal Society, and JOHN PERRY, Professor of Mechanical Engineering and
applied mathematics in the City and Guilds of London Technical College,
Finsbury, in the County of Middlesex "IMPROVEMENTS IN FRICTION GEARING
"
Our invention relates to methods of driving from one shaft to another, and is of
especial importance when the angular velocities of these shafts are very different.
It has been primarily designed for driving ordinary machinery from the rotating
spindle of an electro motor or other quick moving engine, or for driving dynamo
machines and other quick moving machines from ordinary shafting, that is either
in the great reduction of speed or in the great increase of speed.
In order that our invention may be the better understood we now proceed to
describe it with reference to the drawings hereunto annexed, and to the figures and
letters marked thereon.
Figures 1 1 1º, Sheet II, represent in elevation, vertical section, and plan, the
original form of our frictional gear designed by us in 1882. P is a roller keyed
upon the axis of the electrical motor M. H H are two pulloys or riggers pressed
against the roller P by the springs S. S', operating upon the ends of the levers LL,
which carry the centres or bearings of the said pulleys or riggers. A band passed
over either or both of the riggers H H would transmit the rotation of the motor
at a much lower speed. This arrangement was subject to several drawbacks, chicf
amongst these being the pressure upon the journals of the riggers or pulleys H H¹,
caused by the tension of the springs. In seeking to effect a better means of
converting a high rotary velocity into a much lower one, or vice versa, by
frictional gearing, with the least amount of rubbing resistance, we have since
invented the following devices.
In the first part of our invention we employ a pair of rollers (either of which is
keyed upon the driving or driven shaft) running within the trough shaped rim of
a larger wheel, keyed to the other driven or. driving shaft, the rollers and the
trough wheel being pressed into frictional contact with one another by suitable
means hereinafter more fully described. This arrangement is capable of the
following modifications. In figure 1 we drive from the spindle M, which has great
velocity, there being fixed at the end of this spindle a hard metal bush P. Another
roller Qlies against P, and both rollers are held between the two flanges S and T,
on the rim of the large trough wheel whose axis is F. Various means may be
employed to produce considerable pressure between P Q and the flanges of the
large wheel. In some cases we make P and Q frustrums of cones with their axes
intersecting in that of the trough wheel, the flanges of the latter being set out to
coincide with the surfaces of the cones, so that there may be true rolling on all tho
surfaces in contact. Sometimes, as in figure 3, one or other of the rollers has an
annular projection for the same purpose.
To produce the gripping pressure we generally allow the roller Q to be pressed
in the direction of its axis by means of a spring, Q being fitted to its spindle on a
fenther, and in this case we prefer to have the two flanges S and T, on the largo
wheel, somewhat flexible, so that the grip may be more elastic. Sometimes, as is
shown in figures 4 and 15, we have a ring G attached to the flange by springs,
which can be adjusted in position by means of bolts. In all the other parts of
our invention we may employ any of these methods of producing the gripping
pressure.

page_text: -
In figures 5 and 12 we show a rail, or rod, or rope R, inserted between the
gripping wheels P and Q. This part of our invention we employ for the purpose
of propelling a vehicle, (on which either of the large wheels S T F and the
motor and gripping wheels are fixed,) along the rope, rod, or rail R, in
"telpherage," and in other transmission of goods and passengers by means of
electricity.
Instead of the method of figure 2, we may employ a method shown in figure 6.
And in cases where the shaft M is not at right angles to the shaft F, we may
employ the method shown in figure 7.
"
In all these cases either the roller P or the roller Q may be the roller which is
attached to the motor shaft.
In figure 8, the motor spindle and the axis of the driven wheel are parallel to
one another, and it is seen that by making the diameter of the part of the roller Q
which rolls on the inner flange T, smaller than the part of Q which is in contact
with P, it is possible to get nearly true rolling without slipping. This is necessary,
as the inner circumference of the flange S is greater than the outer circumference
of the flange T, and rollers of equal diameter would thus have to slip upon one of
the surfaces of contact.
Figures 9 and 10 show the nature of this method of driving when the roller Q
becomes large in comparison with P, that is, when the internal diameter of the
outer flange S is many times larger than the external diameter of the inner
flange T.
In figure 11 a slight modification of the method is shown, where it is the
roller which is smaller in diameter at the place where the uniform roller Q
touches it, the two diameters of the roller P corresponding in ratio to that of the
inner and outer diameters of the flange S and T respectively.
We show various applications of this,-the first type of our frictional gearing,-
combined with various mechanical devices, in which the means for the transmission
of power, at a greatly reduced speed, or vice versa, is of importance.
Figures 26 and 27 show in elevation and plan, respectively, our electrical
traction motor mounted upon a rail for telpherage purposes. The rotary electrical
inotor M transmits its high speed rotary motion, by the frictional adhesion of its
spring cone P in combination with the second coned roller Q, gripping between the
bevil flanges of the trough wheel H, as herein before described, to the vortical axis J,
and thence to the traction wheel T of the travelling motor.
Instead of allowing the thrust upon the cone P to be carried by the interior
imechanism of the rotary motor M; we prefer to mount the cone P, so as to slide
upon a feather let into the rotating shaft of the motor. Any back thrust of the
cone P cannot thus be communicated to the interior mechanism of the motor, but
is carried by a special collar R, figure 28, mounted in a spring supported lever L,
of which the fulcrum and the spring support is carried by the cover N of the
motor. Figures 29 and 30 show, in elevation and plan, the adaptation of a rotary
electrical motor M, and our improved frictional cone and bevel gearing P, Q,
and H, to the propulsion of a tricycle. In place of the two cones P and Q
frictionally gripping between the bevilled flanges of the trough wheel 'H, we may
use two discs D D₁, figure 31, the circumferences of which ride upon the inner
faces of the flanges T T', and which are pressed thereon by the elasticity of the
spiral spring S between the discs. In this case the axes of the driving and driven
shafts will be parallel to each other.
Alternatively, the said discs D D₁ may be arranged as in figure 32, to press
upon the two exterior faces of the plain wheel H, one disc D being a fixture, and
the other disc D¹ being pressed against the wheel H by the spiral spring N'
reacting against nuts N.
In figures 33 and 34 wc, show in side and end elevation respectively the
adaptation of an electrical rotary motor M, and our improved frictional gear,
to an under hung travelling traction motor for telpherage purposes. The rotary.

page_text: motor M transmits its velocity by the cone roller P, keyed upon its shaft, by
virtue of the frictional grip produced by the pressure of the other spring coned
roller Q, to the flanges of the trough wheel H, and thence through the shaft K to
the traction wheel T, producing tractive effort upon the rail or rope R, supporting
the travelling locomotive.
In figures 35 and 36 we show the adaptation of our improved frictional gear as
already described in connection with Figures 8, 9, 10, and 11. The two dynamo
machines M M receive motion by the rollers P P', keyed to their respective axes,
from the inner face of the outer flange T of the large driving wheel H, which is
keyed on the crank shaft F of a steam engine. A second pressing roller QQ¹
wedges between the aforesaid rollers P P¹ and the inner flange T₁ of the driving
wheel, so as to effect sufficient frictional adhesion. The rollers QQ are carried on
traversing frames, and the amount of gripping pressure is determined by adjusting
nuts and springs S S. An important point in this form of our gearing is that tho
rollers QQ run on a reduced diameter of the rollers P P¹, the ratio of the diameters
on the rollers Por P¹ being similar to that of the diameters of the flanges T and T¹,
so that the rollers PQ and P'Q' shall truly roll upon one another, and at the same
time upon the flanges T and T, which are of different circumferential velocities.
By adjusting the nuts and springs SS, we are able to drive the dynamos with
exceedingly little pressure on their bearings.
The second part of our invention is a form of frictional gearing in which we
produce the epicyclic rotation of a frame carrying two or more rollers, which bear
on one side of their circumferences upon a central roller, transinitting motion, and
are pressed in contact therewith by adjusting appliances within an external fixed
drum, conveniently forming the end frame or cover of a machino.
In figure 13, P is keyed upon the spindle of the motor M, and is gripped between
three rollers Q1 Q3 Q³, and these rollera are centred on the frame G, fastened to the
shaft F. The rollers are gripped on their outside circumferences by the internal
rim of a wheel, ring, or tub H H, the gripping pressure being produced either as
shown in the figure, that is, by the moveable ring J J, which is fastened by springs
to the outer ring L L, the outer ring being attached to the frame, or tub, or wheel,
by the adjustable bolts K ; or, it may be produced by making the part P conical
and adjustable in position; or, in other ways:-the essential difference between
these methods of gearing and some of those lately invented by Professor Fleeming
Jenkin, being duo to our fixing the external part H, and obtaining motion from
the epicyclic rotation of the frame G, carrying pulleys QQQ³. H being a
fixture allows us to make it part of the cover or end of a machine or motor, and
thus to dispense with extra bearings for carrying the shafts. Of course, instead
of employing the three pulleys Qwe may employ two or any higher number.
In figures 37 and 38 we show the application of this last described epicyclic
frictional gearing to an electro-motor M, mounted on a bed plate B, and trans-
mitting its motion at a greatly reduced speed to the shaft F, from which it may be
utilized in the ordinary way, by a belt running on the rigger D. Upon the axis of
the rotary motor M is keyed the driving bush P, and upon this bush ride the three
rollers QQQ³, the centres of which are carried on the frame G keyed to the
shaft F. The rollers Q'Q' Q³ are pressed home upon the roller P by the wedge
ring J, which is adjusted by the screwed ring L.
In figure 14 we show a case in which a much greater reduction in speed is
obtainable, tho fixed tub, or wheel, or frame, gripping the outside of the rollers Q
on their spindles, or smaller drums attached to their spindles, on the two sides of
the pulleys. The fixed frame H may now be in two parts, or be made as one large
casting, so as to embrace the pulleys. It will be observed that in this case, since
the frame with the pulleys Q rotates, and we allow the spindles of the pulleys to
ride in radial slots on the frame, we are able to take advantage of the centrifugal
force due to the rotation of the pulleys, and this will enable us to have a greater
pressure at the places A and B, where the circumferential tractive force is great,.
than at the places C and D, where the circumferential tractive force is less.
J

page_text: Without such a condition being produced, the gearing would be useless, as the
pressure producing adhesion should be proportional to the tractive effort required.
The reduction of speed in this case is not in proportion to the diameters of the
outer and inner rolling surfaces, as it would be if the frame G were fixed, but is
that ratio plus unity.
The third part of our invention relates to the use of friction gearing in a manner
which is analogous to the well known differential gearing, when spur or bevel
wheels are used. In the cases hitherto considered we have been able to balance
the very great pressures which usually act at the bearings of shafts in friction
gearing, and this balancing of pressures we also effect in our differential gearing.
In figure 16, M is a motor spindle whose bearing is in the fixed frame A A, and P
is a roller fastened to the end of the motor spindle. The frames L carry two or
more rollers Qsymmetrically placed, and these rollers are firmly gripped between P
inside, and the fixed tub A A and the moveable tub R R outside. R R is keyed
to the shaft F which we wish to drive. The diameters of the tub A A and of R R,-
and therefore the diameters of the parts of the rollers which roll inside these
tubs, differ by a comparatively small amount, and the smaller the differerice the
greater is the reduction of speed from M to F. The bearings of the rollers Q ride
in radial slots in the frames L, and the gripping pressures may be produced in
many ways, for example, by slightly tapering the rolling surfaces and employing
springs to give to the rollers a longitudinal motion.
In figure 17 it is the frames L, carrying the bearings of the rollers Q in radial
slots as hefore, which rotate with the Motor spindle. The driven shaft F rotates
slowly with the tub R, and the tub A is fixed. The rollers Q are gripped between
the tubs on the outside, and the central piece P, by any suitable method of producing
the necessary pressure, and it is the sinall difference of the internal diameters of
the tubs A and R in comparison with the diameters of the rollers themselves,
which enables us to obtain a very great reduction of speed. For better balancing
of pressures the loose. roller P may have a neck, as shown in figure 17A, instead
of being simply cylindric as shown in figure 17.
Figure 18 does not differ materially in method from Figure 16.
In figure 19 we have the same arrangement as in figure 17 with the central part
left out. It is employed in cases where a dependence may be placed on the
constancy of the speed at which we wish to drive, so that the centrifugal force of
the rotating rollers Q Qu may be sufficient to produce the necessary gripping
pressures on the inside of the tubs R and A.
It is obvious that in cases where our arrangements are so strong that we need
not fear a want of rigidity in the framework, we may employ one roller Q, but
we prefer to use two or more, symmetrically placed, so that the stresses in the
framework shall be balanced.
In figure 20, if one of the rollers P¹ or P¹¹ is keyed to the spindle M, and the
frame is loose, we have the same method as that shown in figure 16, P being
divided into two parts. This figuro 20 is also the method of figure 17, if the
frame L were keyed to the spindle M, and the rollers P' and P¹¹ were loose.
To produce the gripping pressures we may, as already described, have any of the
rollers conical; or, we may employ a spring acting longitudinally, using the
principle of the wedge. Or again, the method may be that shown in figure 13,
where a wedge shaped ring on any of the tubs is acted on by springs. Again, the
method may be that of figure 15, where the ring K is pressed out against a roller
by means of a continuous spring all round the flange T, or a set of springs. Again,
the method may be a modification of the gravitation grip shown in figure 12,
gripping a pulley instead of a rail.
In figure 21, the tub A A has a ring CB, which encloses the spring D, whose
coils are of large diameter, between itself and A. It is on the internal surface of
this spring D that the rollers Q roll, and the motion of the wedge in the direction
CF causes the coils of the spring to tend to become smaller in diameter, thus
producing the requisite gripping pressure on the rollers Q. It is the wedge-likė

page_text: shape of the ring CB which produces this effect. When we have no wedge-shaped
backing to the spring, it is an elongation of the spring in a direction parallel to FC
which gives the grip
.
Figure 22 shows this method applied to a roller P on the spindle M. When the
nuts F and F are tightened, the spiral spring B is made to expand on the cone P
and grip the rollers QQ. When there is no cone touching the inside of the
spring, the natural tendency of the coils of the spring to expand, when the spring
is shortened, is sufficient to produce the grip, and this is helped by letting the end
of the spring lie in a recess in the nut F, so that turning the nut causes unwinding
of the coils of the spring.
In figure 23, the coned collars C C slide freely on a feather on the spindle M.
A spiral spring B presses the collars apart, and causes them to grip the
rollers QQ In figure 24, the collars C C are drawn together by the spring B,
and thus grip the rollers Q¹. Q¹¹.
Figure 25 shows the tightening method of figure 13 as applied to the differential
gearing of figures 10 and 20. The tightening of the wedge shaped ring J J causos
the pulleys to bear on both the tub A and the tub B.
Having described and ascertained the nature of our invention and the manner of
carrying the same into effect, be it known that we are aware that devices for the
transmission of power or motion frictionally, by rollers pressed between the
transinitting and receiving surfaces, are already known and used; we do not
therefore attempt to claim the same broadly, but what we desire to protect by
Letters Patent and claim as our invention is:-
First. The combination of a flanged or trough wheel on the driven or driving
axle, with a pair of rollers which are frustrums of cones, rolling in the said trough,
one cone being attached to the driving or driven axle, the axes and surfaces, both
of the rollers and of the flanges of the trough-wheel, intersecting in the axis of the
trough-wheel; to transmit motion or power, from axes at right angles to each
other by frictional adhesion, and with true rolling between the surfaces in contact,
substantially as described and shown in figuros 2, 26, and 34.
Second. The modification of the above gearing where the axes of the driving
and driven shaft are oblique to one another, the trough of the flanged wheel being
placed obliquely to suit, the axes of the cones meeting in the axis F F, reference
being had to Figure 7.
Third. The combination of a flanged or trough wheel upon a driven or driving
axle, the trough being perpendicular to the plane of the wheel; with a pair of
rollers, rolling in the said trough, and one being attached to the driving or driven
axle, and one roller being provided with contact surfaces for the other roller and
the trough flange, of diameters bearing the same ratio as those of the flanges of the
trough on which rolling occurs; to transmit motion or power, from axes parallel to
cach other, by frictional adhesion, and with true rolling motion between the
surfaces in contact, substantially as described in reference to figures 10, 11, 35
and 36.
Fourth. The combination of an epicyclic train of rollers mounted in a frame
upon the driven or driving shaft, with a central roller, upon the driving or driven
shaft, and an external enclosing fixed frame, and adjusting pieces therein, effecting
frictional grip between the said train and the central roller; to transmit motion or
power from shafts in the same line, substantially as described with reference
to Figures 13, 37, and 38,
Fifth. The modification of the above gearing, in which the epicyclic train of
rollers presses with their axes of small diameter upon' the inner circumference of
the fixed enclosing frame, the centrifugal pressure of the rollers being utilized to
develope adhesive pressure, proportional to the tractive force required, substantially
as described in reference to figure 14.
Sixth. The combination of two drums or tubs of slightly different diameters,
one stationary and fixed, and the other attached to the driven or driving shaft,
and of a central bush or roller upon the other driving or driven shaft; with a

page_text: train of one or more epicyclic rollers carried in a freely revolving frame; forming
a differential motion between the two drums or tubs for the transmission of
motion or power at any desired ratio from two shafts in the same lino,
substantially as described with modifications in reference to Figures 16, 17, 18, 19,
and 25.
Seventh. The combination with the conical roller in our rim gearing, the subject
of claims 1, 2 and 3, whether idle or upon the driving or driven shafts, of a spring
re-acting along the axis of the shaft or at any anglo with it; to effect the wodging
action of the conical roller, to produce traction grip, substantially as described
Eighth. The construction of a self expanding roller or self contracting flange,
composed of a spring or springs, the automatic expansion or contraction being duo
either to the inherent clasticity of the springs, or to the pressure of a cone or
wedge, reference being had to figures 21, 22 and 34.
'
In witness whereof wo the said William Edward Ayrton and John Perry have
hereunto set our hands and seals this twentieth day of December in the year of
our Lord one thousand eight hundred and eighty-three
--