IMPROVEMENTS IN DRIVING GEAR
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by the said Fleeming Jenkin at the
Office of the Commissioners of Patents on the 14th April 1883.
FLEEMING JENKIN of 3 Great Stuart Street Edinburgh Civil Engineer
"IMPROVEMENTS IN DRIVING GEAR'
"
My invention has for its object the diminution of the loss by friction in trans-
mitting power by gearing. When toothed wheels are employed unnecessary friction
takes place chiefly at the surfaces of the teeth. When belting is employed
unnecessary friction takes place chiefly at the bearings. When what is sometimes
called frictional gearing is used such that the transmission of power depends on
the friction between two solid wheels still more unnecessary friction is caused at
the bearings.
My invention applies only to gearing consisting of circular wheels or circular
wheels and racks, and in all the varieties hereafter described the improvement is
obtained by the application of one common system namely the reduplication of
parts so arranged that the pressure required to produce adhesion by friction shall
not cause pressure to be put on the bearings. I have given the name of "nest
gearing" to my invention First in order to multiply or reduce, the angular velocity
ratio to such moderate extent as would with toothed wheels be effected by a spur
wheel and pinion. I employ a smooth cylindrical roller A of small size working
between two smooth cylindrical rollers B and C-this nest is pressed together by
the internal surface of a ring on a
wheel D the surface velocities of the
outside of A and the inside of 1) are the same and their angular velocity ratio is
inversely proportional to the radii of these two surfaces. The small roller ▲ may
be outside B and C pressed directly against the inside of D. The rollers A B and Č
may be equal or unequal-if unequal we shall have four different angular velocities
all inversely proportional to the several radii, The rollers are kept by suitable
bearings with their centres on one diameter of D but these bearings allow absolute
Price 1027

page_text: freedom to the centres A B and C to adjust themselves relatively to that of D or
what comes to the same thing absolute freedom to three of the centres to adjust
themselves relatively to the fourth. In consequence of this freedom the normal
pressure by D on the inner rollers and the reciprocal normal pressure of the inner
rollers on D causes no pressure whatever on any bearing. This normal pressure
may therefore be of any desired or necessary amount to secure adhesion without
causing any injurious friction.
The necessary tightening may be effected in three ways: 1st by initial adjust-
ment depending on accurate turning. 2nd by the end movement of roller A may
slightly taper for this purpose. In this case a small bulge or projection is formed
on B and C or the edge is slightly rounded. If the bulge is formed a corresponding
hollow is left inside D so that the flat cylindrical part of B and C can bear against D
-this description refers to the first arrangement described. Analogous changes
can be made in the second arrangement. 3rd By jamming one of the three rollers
between two centres by a sideway movement: when this mode is used the four
wheels will not have their centres absolutely in a straight line except as a limiting
position and this is a defect for the roller B or a pair of rollers B₁ B' may be
substituted the three centres of CB B' then form a triangle and A runs in the
middle of these rollers. A may have a hollow spindle and the axis of D pass
quite through it. By placing A more or less excentrically the tightening of the
rollers can be effected by varying the shape of the triangle of centres. Although
called concentric this is a mere name and I do not affirm thereby that any two
wheels are concentric...
Secondly when it is desired still further to multiply or reduce the angular
velocity ratio I employ as before a small cylindrical roller A now placed between
two rollers B and C and bearing against a surface of comparatively large diameter.
These wheels have smaller concentric cylindrical surfaces bearing against the inner
ring of D-In this arrangement the surface volicity of D relatively to that of A
is diminished in the ratio of the large to the small diameters of the two parts of
either the roller b or roller c. This ratio must be the same in B and C-calling
this ratio m and n the ratio of the diameter of D to that of A. the angular velocity
of A will be m n times that of D.
The arrangements as to centres are analogous to those in the first plan and it
is desirable that the smaller cylindrical surfaces of B and C should be divided into
two parts one on each side of the surface of larger diameter-this larger portion
then revolves free inside a
or cage connecting the two parts of the ring D
-this arrangement keeps the resultants of all the pressures in one plane-the
means of tightening are those described for the first case.
'
In the foregoing the axes of the rollers are all parallel. I call the above
concentric nest gearing.
Thirdly when it is desired to change the direction of the rotation as by bevil
wheels this direction can be changed through 90° by arranging the rollers as
follows:-
Two cylindrical rollers B and C are pinched between the inner side Surfaces of
the two parts D¹ D² of cylindrical wheels keyed on a shaft parallel to the common
perpendicular to the axes of B and C-the pinching is most simply effected by a
stout spring forcing D' and D' together for which purpose D' or D' slides on
a feather but other modes of pinching analogous to those described above may be
employed,
The surface velocity of D¹ and D' is the same as that of B and O and the
angular velocity ratio is inversely proportional to the radii; in order to avoid
grinding action the surfaces of D₁ and D* should touch those of B and C only at a
point or any small surface-this is easily secured by slightly rounding the surfaces
either of D and D³ or of B and C. The two cylindrical surfaces of B and C need
not be of the same diameter-and the centres of B and C are free to approach.
I call this gearing right angle nest gearing.
Fourthly-A rack action may be combined with the last described right angle

page_text: nest gearing by letting a straight rod or rope A run between the rollers B and C.
The pinching action of D' and D' secures the necessary adhesion both between
D' B, D' C, B A and C A with no force exerted on any bearing-this gearing may
be employed to drive the rack or if the rack be stationary such as the rail of a
railway or the rod or rope of a Telpherage line the rack action will cause the
gearing or carriage to move along the rack. I call this gearing the rack nest
gearing.
-
Fifthly The before described rack nest action may be applied to drive a flexible
band or belt and this band or helt may in its turn be employed to drive a pulley
by means of a similar nest rack action and I am by this means enabled to drive
one pulley by another at a distance as by ordinary belting-the direction of the belt
may also be changed more easily than with ordinary belting. The pinching nest
may be placed at any point of the periphery where the belt touches it and several
pullies may be driven from one belt. Wherever the pinching nest is placed the
pull between the pullies is limited to that required for the transmission of the force
instead of being as is the case with ordinary belting greatly in excess of the_pull
pressure on the bearings giving rise to friction is thus greatly diminished. I call
this the belt nest gearing.
Sixthly I gear two flat pullies so as to run like the ideal pitch surfaces of a
spur wheel and pinion either in internal or external gear by means of a pinching
arrangement analogous to that used for the nest rack action. Thus let the problem
be that of external gearing and let A be the smooth pulley with a surface
corresponding to that of the pitch surface of the spur wheel and let B be a smooth
pulley bearing on the outer surface of A the surface of B corresponds to the ideal
pitch surface of a pinion-a pair of rollers D' D' is placed with its axis at right
angles to that of A and B and these rollers bear against the outer cylindrical
surface of B' and a second pulley B' bearing on the inner surface of A so as to
press A and B together sufficiently to prevent their slipping-D' and D³ are
pressed together by a spring as in the previous examples. By an obvious
modification B¹ might be in internal gearing with A. This gearing I call the nest
parallel gearing. The bearing rings of D1 and D2 must bear the same ratio to
each other as the internal and external surfaces of A. If the pulley D¹ D' is used
to drive A or vice versa this arrangement gives a second variety of right angle nest
gearing.
Seventhly. In the nest gearing described so far the axes have either been parallel
or at right angles-but the system is applicable when the direction of the axes are
inclined in any direction.
I will now describe nest arrangements for inclined intersecting axes.
I will now
show the modifications of all the types but will describe the modifications of the
leading types required for this purpose-as the first example I select the first
described concentric nest gearing.
In this gearing let the axis of D be inclined to the direction of the three parallel
axes of A. B and C; if B and C are simply rounded they will then press on paths
which are two parallel circles inside the smooth barrel D. If the inclination be at
all considerable shoulders will be desirable to check the slipping of B and C
lengthways inside the barrel. To prevent grinding and give a larger bearing than
a simple point those shoulders and the surfaces of B and C may be bevelled so as
to run like the pit surfaces of bevil wheels suitable flat surfaces are then provided
for the bearings between A. C and B.
Eightly. As my next example of an oblique nest. I will describe a modification
of the right angle nest described under the heading sixthly-The rim of B instead
of being at right angles to the plane of the wheel is dished or bevilled and then
gripped between the rollers B'. B. which are pinched by the pair D' D³ the axis of
which is at right angles to the rim as before-but since the rim is now inclined the
axis of D¹ D'. will also be inclined to the axis of A by more or less than a right
angle.

page_text: As one case of this arrangement the axes will be at right angles and the rim of A
will run in the plane of revolution
Ninthly. The place of the solid concentric pinching rim of my first concentric
nest gearing may be taken by a flexible belt and we then have gearing more
clearly resembling some arrangements already in use but in which so far as my
knowledge goes the principle of leaving absolute freedom to the axes to arrange
them selves as to distance and parallelism so as to avoid all unnecessary friction
on the bearings has not been carried out the flexible belt may be tightened by a
jockey or by the coning of one wheel. A belt may also be employed for the
second concentric nest gear.
Tenthly. Right angle or oblique nest gearing may be employed to produce easily
variable velocity ratios. Thus in the right angle nest gearing under heading 3° of
the rollers B and C are made to approach the axis of D. D, their speed will be
diminished-if they are made to leave this axis their speed will be increased-a
slight tipping in one direction or the other may be used to produce this approach
or recess.
Elevently Nest gearing may be used instead of friction clutches or it
may be
used as a substitute for the fast and loose pullies employed in belting-for this
purpose it is sufficient to provide that the pinching pressure shall be under control
so that when driving is to cease this pressure may be diminished until the gear
slips.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Fleeming Jenkin in the Great Seal Patent Office on the 13th October
1883.
FLEEMING JENKIN of 3 Great Stuart Street Edinburgh Civil Engineer.
"IMPROVEMENTS IN DRIVING GEAR
"
My Invention has for its object the diminution of the loss by friction in
transmitting power by gearing and in many cases subsidiary advantages would
follow its adoption. When toothed wheels are employed unnecessary friction takes
place chiefly at the surfaces of the teeth; noise and liability to breakage are
further disadvantages of toothed gearing. When belting is employed unnecessary
friction takes place chiefly at the bearings. There is also a loss from the bending
of the belts and there is a difficulty in regulating their tension. When what is
sometimes called frictional gearing is used such that the transmission of power
depends on the friction between two solid wheels still more unnecessary friction
is caused at the bearings and in some forms much grinding at the surfaces of
contact.
My invention applies only to gearing consisting of circular wheels or circular
wheels and racks, that is to say my invention does not apply to any combination
of toothed wheels or toothed wheels and racks on the one hand nor on the other
hand is it applicable to smooth surfaces of elliptical or hyperboloidal section. In
all the varieties of gear hereafter to be described the parts in gear have sections
which are either circular or straight and in all the varieties hereafter described the
improvement is obtained by the application of one common system namely the
reduplication of parts so arranged that the pressure to produce adhesion by friction
shall not cause pressure to be put on the bearings. I have given the name of
"nest gearing" to my invention.
I will now describe some examples of the first type of nest gearing.
In order to multiply or reduce the angular velocity ratio to such moderate
extent as would with toothed wheels be effected by a spur wheel and pinion. I
employ as is seen in Figure 1 a smooth cylindrical roller A of small size working
between two smooth cylindrical rollers B and C. This nest in which B and C are
the reduplicated parts is pressed together by the internal surface of a ring on a
wheel D, this ring is the nest ring. The surface velocities of the outside of A and
the inside of D are the same and their angular velocity ratio is inversely propor-
tional to the radii of these two surfaces. The three rings A, B, C enclosed by the
ring D form what I call a nest. The small roller A. may be outside B and C and
pressed directly against the inside of D. The rollers A, B and C may be equal or
unequal-if unequal we shall have four different angular velocities all inversely
proportional to the radii. The rollers are kept by suitable bearings with their
centres on one diameter of D but these bearings allow absolute freedom to the
centres A B and C to adjust themselves relatively to that of D or what comes to
the same thing absolute freedom to three of the centres to adjust themselves
relatively to the fourth. Thus any one of the rollers shown in Figure 1 might
have its centre in a determinate position and the other centres would then have
motions relative to this one. In consequence of this freedom the normal pressure
by D on the inner rollers and the reciprocal normal pressure of the inner rollers
on D causes no pressure whatever on any bearing. This normal pressure may
therefore be of any desired or necessary amount to secure adhesion without causing
any injurious friction.
The necessary tightening may be effected in three ways 1" by initial adjustment
depending on accurate turning.

page_text: Secondly the tightening may be effected by the end movement of roller A made
slightly taper for this purpose as in Figures 1 and 1ª. In this case a small bulge
or projection is formed on B and C or the edge is slightly rounded. If the bulge
is formed a corresponding hollow is left inside D as shown in Figure 1° so that the
flat cylindrical part of B and C can bear against D. I attach much importance to
the subdivision of the roller into parallel bands so that the cone or cones bear
only at oue side of the intermediate rollers the other side being supported by a flat
band. The bulge or rounding shown in Figure 1ª is intended to avoid the grinding
action which would result from one cone inside another but where this grinding
action is unimportant the surface of the roller may be turned with cones which fit
giving a larger bearing surface suitable for greater pressures.
I prefer to use double cones as shown in Figure 2 which by their pinching
produce the same wedging action as a single cone without injurious end friction.
In this case, as in the simple conc, cone surfaces may be employed as shown in
Figure 2 where the grinding action is not objectionable, and curved surfaces as at
Figure 1 when no grinding is desired. In this example as in the previous one
there is a flat cylindrical part on the coned rollers B and C to avoid unnecessary
grinding. These rollers are made each in two parts which are drawn together by
a flat spring abutting on a nut.
In Figure 3 another variety of this type of nest is shown with the pinching
exerted by the outer or nest ring.
In this example the nest ring D is in two parts which are drawn together by
springs.
In all these varieties the device of separating the rollers into parallel bands is
adopted so that the flat or cylindrical part of two of the rollers can bear against a
third.
In the varieties of nest gearing above described the central roller may run inside
three or more rollers instead of two as shown in the Drawings and I prefer to
employ three as in the examples presently to be described.
Thirdly. The necessary tightening can be effected by jamming one of the three
rollers between two centres by a sideways movement as in Figure 4 when this
mode is used the four wheels will not have their centres absolutely in a straight
line except as a limiting position and this is in my opinion to some extent a defect.
Or a pair of rollers B, B, may be advantageously substituted for the single roller B,
the three centres of C. B, B, then form a triangle and A runs in the middle of these
rollers. A may have a hollow spindle and the axis of D pass quite through it. By
placing A more or less eccentrically the tightening of the rollers can be effected by
varying the shape of the triangle of centres.
I call this mode of tightening the eccentric method.
Figures 5 and 5 shew diagrams of one arrangement of nest gear tightened in
this way the roller A which I may call a pinion is fast to a shaft which drives it.
It is geared with the nest ring D also fast to a shaft which is driven as though D
were an internal spur wheel. The tightening is effected by forcing B¹ or B³ or
both into the narrower part of the space between the idle roller C and the nest
ring D-C is a hollow spindle and requires no shaft.
Figures 6 and 6 and Gb show another arrangement of nest gear tightoned in
this way. The roller A which I may call a pinion fast to a shaft which drives it
is geared with the ring C on a shaft which is driven as if C were an external
spur wheel. The mode of tightening is obvious--by turning a right and left screw
the rollers B' and B2 can be forced into narrower parts of the space between the
outer ring D and the ring C.
Figures 7 and 74 give a diagram of a third of these arrangements in which
A is driven by a shait fast to its end and is placed eccentrically relatively to D
which is driven.-In this case the roller A fast to a shaft is supported by the
intermediate rollers and driven by being in gear with these externally while they
are in gear internally with the nest ring. Obviously the drivers and followers
may be inverted in all these cases.

page_text: Figures 8 and 8 show how by splitting up rollers such as B' B in concentric
bands these rollers can be placed nearer than would otherwise be possible.
In all these examples only one of the five rings ought to have its centre fixed,
the centres of the others must be free to move in the direction of the normal
pressure against the nest ring, the tightening may in all cases be described as
effected by changing the shape of the triangle of the centres.
It must be understood that I purposely avoid showing constructive details and
usė diagrams which I consider more easly understood-thus in place of the bushes
sliding in slots mere circular fixed bushes may often be used made large enough
relatively to the pins to ensure the absence of pressure due to the nest ring and
again the rollers may be supported on links to secure greater freedom than even
the sliding bushes give.
The three modes of tightening above described for the first type of nest gear
are termed by me the method of initial fitting-the wedge method and the
eccentric method. They are all applicable mutatis mutandi to other varieties.
In all I may produce the pressure against the enclosed nest ring-rings or discs by
initial fitting by a wedge action in the direction of an axis or by the sideways
motion of the axes.
Although I have called later all these varieties of nest gearing concentric
this is a mere name and I do not affirm thereby that any two wheels are
concentric.
I will now describe what I term the second type of nest gearing. When it is
desired still further to multiply or reduce the angular velocity ratio I employ as
before and as in Figures 9 and 9* a small cylindrical roller A now placed between
two rollers B and C and bearing against a surface of comparatively large diameter.
These wheels have smaller concentric conical surfaces b₁ b, c, c₂ bearing against the
inner ring of D. In this arrangement the surface velocity of D relatively to that
of A is diwinished in the ratio of the large to the small diameters of the two parts
of either the roller 6 or roller a This ratio must be the same in B and C calling
this ratio m and calling n the ratio of the diameter of D to that of A the angular
velocity of A will be m n times that of D.
The arrangements as to centres are analogous to those in the first plan and it is
desirable that the smaller conical surfaces of B and C should be divided into two
parts as shown in Figure 9" one on each side of the surface of larger diameter
this larger portion then revolves free inside a cage consisting of the two parts
D1 and D2 of the ring D. This arrangement keeps the resultants of all the
pressures in one plane. The means of tightening are those described for the
first case.
Thus in Figures 9 and 9 the wedge method of tightening is adopted with
double cones embraced by the nest ring. In Figures 10 and 10" the eccentric
method with three reduplicated rollers is adopted. The two parts of the nest ring
are not necessarily rigidly connected and these are shown separated in Figure 10%.
The two parts might be designed to revolve with different velocities if c and b¹,
were of different diameter to c² and b². A less perfect arrangement but one which
may be useful is obtained when one of the two nest rings is omitted altogether,
a couple is then produced by the fact that the pressures on the larger and smaller
bands are not in one plane but this couple may be small if the arm is small and
may be resisted by a small but distant pressure on the shaft which has its centre
definitely fixed.
In all the foregoing varieties of the two first types the axes of the rollers are all
parallel, I call the above varieties concentric nest gearing.
Third Type. When it is desired to change the direction of the rotation as by
bevil wheels. This direction can be changed through 90° by arranging the rollers
as follows:-
Two cylindrical rollers B and C figure 11 which are the reduplicated rings are
pinched as by a nest ring between the inner side surfaces of two cylindrical wheels
or discs D¹ D keyed on a shaft parallel to the common perpendicular to the axos

page_text: •
of B and C. The pinching is most simply effected as in Figure 11 by a stout
spring forcing D' and D³ together for which purpose D' or D° slides on a feather,
but other modes of pinching analogous to those described above may be employed
that is to say I may employ initial fitting or wedging or sideways motion.
The surface velocity of D' and D' Figure 11 is the same as that of B and C an d
the angular velocity ratio is inversely proportional to the radii. In order to avoid
grinding action the surfaces of D' and D² should, if there is to be no end pressure
causing unnecessary friction, touch those of B and C only at a point or any small
surface-this is easily secured by slightly rounding the surfaces either of D' and D'
or of B and C.
The discs D¹ D² are nest discs-B and C are the reduplicated parts-the
pressure against the nest rings or discs produces absolutely no pressure on any
'bearing.
Figure 12 shows one arrangement in which tightening is effected by my second
method of wedging. It is a side vertical elevation partly in section. Figures 12ª
and 12b show other views.
The rings or discs D1 D2 D3 etc are all fast on one shaft d.
The rollers BCB'C' are wedged by their weight between D¹ D2 D3 D³ etc, they
fare provided with suitably bevilled surfaces for the purpose-B and C bear against
each other by flat bands so as to transinit the pressure from D¹ to D² or from D² to
D³ with no couple on the shafts of B' C¹ or B˚C. The lower band may be omitted
as in Figure 13 if the bearings of B C B' C¹are some way off. In that caso the
small couple resulting when the pressure on the wedge not directly meeting the
pressure on the band causes small friction. The two cones must go down together-
a spring may be employed to force them in-or they may be moved forward on a
frame.
Figure 14 shows another arrangement in which the tightening may be effected
either by the independent spring or by wedging. It has the advantage that the
speed of d is reduced. The surfaces shown bevilled may be cylindrical if end
When bevils are
pressure is to be avoided so as to produce a perfectly true nest.
employed it is clear that they should correspond with the pitch surfaces of bevil
wheels.
In all these forms D' D³ which I will call nest discs act in a way analogous to
the nest ring already described.
The two cylindrical surfaces of B and C need not in any of the examples given
be of the same diameter and the centres of B and C should always be free to
approach. In Figure 11 the bearing of C is shown as a bush working in a slot no
pressure applied by D1 D2 puts any pressure on any of the shafts b, c or d: Any of
the shafts may obviously be the driven and any other the follower. The third
mode of tightening may be adopted as shown in Figures 15 and 15ª where the
rollers B and C are jammed between D¹ D³ by twisting the frame holding B and C
from an oblique position towards a central position parallel to the axis of d. I call
this third type of gearing right angle nest gearing. It may however be used for
parallel driving as when b is the driving shaft and the driven shaft. The parts
D¹ d D' viz: the axis, and the discs with the two roller paths upon them act as a
pinching arrangement in substitution for the nest ring in concentric gearing.
Fourthly. A rack action may be combined with the last described right angle
nest gearing by letting a straight rod or rope A as in Figure 16 run between the
rollers B and C. The pinching action of D and D³ secures the necessary adhesion
both between D' B, D³ C, B A and CA with no force exerted on any bearing.
This gearing may be employed to drive the rack-or if the rack be stationary, such
as the rail of a railway or the rod or rope of a Telpherage line, the rack action will
cause the gearing or carriage to move along the rack. I call this gearing the rack
nest gearing.
Figure 17 shows a modification of this rack gearing in which the nest disc bears
against surfaces of B and C which are concentric with those which bear against
the rack. The relative velocity of the nest discs is thus lessened.
The inner

page_text: surfaces are shown bevilled-this gives some end friction and therefore forms a less
perfect nest but the gain of surface may make the modifaction [sic] useful. This
arrangement is the analogue of the second variety of concentric gear. It is further
clear that the rack action may be tightened by wedging against the surface of the
rack or by wedging against bevil surfaces between D₁ D, and B, C₁.
Fifthly. The before described rack nest action may be applied to drive a flexible
band or belt and this band or belt may in its turn be employed to drive a pulley
by means of a similar nest rack action and I am by this means enabled to drive
one pulley by another at a distance as by ordinary belting. The direction of the
belt may also be changed more easily than with ordinary belting. The pinching
nest may be placed at any point of the periphery where the belt touches it and
several pullies may be driven from one belt. Wherever the pinching nest is placed
the pull between the pullies is limited to that required for the transmission of the
force instead of being as is the case with ordinary belting greatly in excess of the
pull; pressure on the bearings, giving rise to friction which is thus greatly
diminished. I call this the belt nest gearing. Figures 18 and 19 show two varieties
of belt nest gearing.
Sixthly. I gear two flat pullies so as to run like the ideal pitch surfaces of a
spur wheel and pinion, either in internal or external gear, by means of a pinching
arrangement analogous to that used for the nest rack action. Thus let the
problem be that of external gearing and let A Figure 20 be the smooth pulley.
with a surface corresponding to that of the pitch surface of the spur wheel and
let B¹ be a smooth pulley bearing on the outer surface of A. The surface of B'
corresponds to the ideal pitch surface of a pinion. A pair of rollers D¹ D' is
placed with its axis at right angles to that of A and B and these rollers bear
against the outer cylindrical surface of B' and a second pulley B³ bearing on the
inner surface of A so as to press A and B¹ together sufficiently to prevent their
slipping. D' and D³ are pressed together by a spring as in the previous examples.
By an obvious modification B¹ might be in internal gearing with A in fact B¹
and B' would simply change places. This gearing I call the nest parallel gearing.
The bearing rings of D' and D' must bear the same ratio to each other as the
internal and external surfaces of A. If a pulley on the shaft of D' D³ is used to
drive A or vice versa this arrangement gives a second variety of right angle
nest gearing by putting a belt between A and B' we obtain another variety of
belt nest gearing.
Seventhly. In the nest gearing described so far the axes have either been
parallel or at right angles-but the system is applicable when the direction of the
axes are inclined in any direction. Thus in the arrangement shown in Figure 20
the rim may be tapered as represented in Figure 20 bis. and the axes of the
rollers bearing upon it inclined—the nest rings bearing on them will then have
bevilled surfaces.
I will now describe other nest arrangements for inclined intersecting axes.
I will not show the modifications of all the types but will describe the modifications
of the leading types required for this purpose. As the first example I select the
first described concentric nest gearing.
:
In this gearing Figure 21 let the axis of D which is a nest ring with two roller
paths upon it be inclined to the direction of the three parallel axes of A. B and C;
if B and O are simply rounded they will then press on paths which are two
parallel circles inside the smooth barrel D. If the inclination be at all considerable
shoulders will be desirable to check the slipping of B and C lengthways inside the
barrel. To prevent grinding and give a larger bearing than a simple point those
shoulders and the surfaces of B and C may be bevilled as shown in the drawing
so as to run like the pitch surfaces of bevil wheels. Suitable flat surfaces are then
provided for the bearings between A. C and B. as clearly shown in the drawing.
In Figure 22 another modification is shown with wedge tightening. A might be
made with a double cone, A pinching B and O.
Eighthly-As my next example of an oblique nest I will describe a modification

page_text: of the right angle nest described under the heading sixthly. The rim of A
Figure 23 instead of being at right angles to the plane of the wheel is dished or
bevilled and then gripped between the rollers B¹. B. which are pinched between
the two roller tracks upon the pair D¹. D. the axis of which is at right angles to
the rim as before-but since the rim is now inclined the axis of D¹. D². will also
be inclined to the axis of A by more or less than a right angle.
As one case of this arrangement the axes will be at right angles and the rim of A
will run in the plane of revolution as in Figure 24. The rings can be made with
bevil surfaces if end pressure is allowed.
Ninthly. The place of the solid concentric pinching rim of my first concentric
nest gearing may be taken by a flexible belt and we then have gearing more
nearly resembling some arrangements already in use but in which so far as my
knowledge goes the principle of leaving absolute freedom to the axes to arrange
themselves as to distance and parallelism so as to avoid all unnecessary friction on
the bearings has not been carried out the flexible bolt may be tightened by a
jockey or by the coning of one wheel. A belt may also be employed for the second
concentric nest gear but I shall make no claim in respect of these nests with
flexible rings or belts.
Tenthly. Right angle or oblique nest gearing may be employed to produce
easily variable velocity ratios.. Thus in the right angle nest gearing under
heading 3° if the rollers B and C in Figure 25 are made to approach the axis
of D'. D. their speed will be diminished; if they are made to leave this axis their
speed will be increased, a slight tipping in one direction or the other may be used
to produce this approach or recess.
Eleventhly. Nest gearing may be used instead of friction clutches or it may be
used as a substitute for the fast and loose pulleys employed in belting for this
purpose; it is sufficient to provide that the pinching pressure shall be under control
so that when driving is to cease the pressure may be diminished until the gear
slips but I make no special claim in respect of putting the pinching pressure
under control so as to form a friction clutch.
i
Since filing my provisional specification I have learnt and I am now aware in
the first place that nest rings with internal rollers arranged in modes similar to
some of those described in my first variety of concentric uest gearing have 'been'
described in Germany by Mechwart in arrangements for relieving the pressure on
the axes of rolling and grinding machinery but, I believe that Mechwart never
contemplated the use of these arrangements as driving gear fit to replace tootlied
wheels as a connection between-shafting.
I am also now aware that the principle of nest géaring as exemplified by my
first variety has been previously described. Foster in a Provisional Specification
which he abandoned-N° 4208 in the year 1882 described one form of this nest
gearing tightened by a double pinching cone. I claim nothing which has been
published by Mechwart or Foster and more particularly I claim in concentric nest
gearing no arrangement which does not change the velocity of shafting.
I claim :-
2
1° In concentric nest gearing whether of the 1st or 2nd types and in which the
tightening is effected by a single or double cone I claim the use of coned rollers
divided in bands one or more of which are flat so applied that the flat or cylindrical
part of two or more of the rollers bear against a corresponding flat or cylindrical
part of another.
2° Concentric nest gear described as of the first type tightened by the eccentric
method and coupling two shafts fast respectively to the nest ring-and. to one of
the enclosed rings in contact with it so that the angular velocity of one shaft shall
in the other shaft be increased or decreased as by an internal pinion and spur
wheel.
3° Concentric nest gearing described as. of the first type tightened by the
eccentric method and coupling two shafts fast. respectively to two of the internal

page_text: rings so that the angular velocity of one shaft shall in the other shaft be increased
or decreased as by an external pinion and spur wheel.
4° Concentric nest gear described as of the first type tightened by the eccentric
method and coupling two shafts fast respectively to the nest ring and one other
ring not directly in contact with the nest ring but connected as when a pinion and
internal spur wheel are joined by an intermediate spur wheel.
5° Concentric nest gearing tightened by the eccentric method and in which the
outer nest ring, itself supported by the bearings of a shaft, serves to support the
innermost roller A by means of the reduplicated intermediate rollers used to change
the velocity of the shafting.
6° I claim concentric gearing of the second type in which the intermediate rings
or rollers are of two diameters and the velocity of the coupled shafts is varied in a
duplicate ratio.
7° I claim right angle nest gearing as described under head 3°
8° I claim rack nest gearing as described under head 4°
9° I claim the belt gearing described under hend 5°
10° I claim the parallel nest gearing described under head 6°
11° I claim the oblique nest gear described under head 8° including the right
angle variety.
12° I claim the mode of varying velocity described under head 10°
13° I claim nest gearing in which the nest rollers are embraced between two
discs or rims mounted upon an axis.
In witness whereof I the said Fleeming Jenkin have hereunto set my hand
and seal this twelfth day of October in the year of our Lord One thousand eight
hundred and eighty three
FLEEMING JENKIN (L.S.)
FLEEMING JENKIN (L.S.)