Improvements in Frictional Driving Mechanism.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improvements in Frictional Driving Mechanism.
I, ROBERT EDWARD PHILLIPS, of 70, Chancery Lane, London, in the County
of Middlesex, Chartered Patent Agent, do hereby declare the nature of this
invention which has been communicated to me from abroad by Albert H. Overman,
of Chicopee Falls, Mass., U.S.A., Cycle Manufacturer, to be as follows:-
This invention relates to frictionally driven variable speed devices and it has
for its object the construction of mechanism of this class whereby greater effi-
ciency is attained, and whereby means are provided for the disengagement of the
driving and driven members of the device at a point where the speed of the
driven member is reduced to zero; and a further object of the invention lies
in the construction of means for compensating for the wear of the engaging sur-
faces of the driving or driven members, whereby the member through which
the variable speed is attained may never be subjected to any lateral pressure
which would tend to deflect the axis thereof from a straight line and cause it to.
bind in its bearings.
This invention has particular reference to that class of devices in which two
discs are employed whose axes are located at right angles one to the other, and
the edge of one of which discs bears on the side of the other, which is the driving
member, and is movable radially thereon for the purpose of effecting a varia-
tion in the speed of rotation of the driven member. This construction is old
hut is impracticable except for the transmission of a small amount of power,
because of the fact that the amount of power which can be transmitted through
devices of this kind, depends entirely on the frictional engagement between the
edge of one of said discs with the side of the other. To make this engagement
constant, the driven member has sometimes been located between two discs having
a common axis, one of which dises has served as a driving disc and the other
being idle and spring-pressed toward the said driving-disc. Sometimes the
driven-disc is otherwise forced against the driver. Such a construction, of course,
has no advantage in point of efficiency over a construction in which one disc is
pressed against the other by any other means, for but one of the discs is a
driver.
In carrying out this invention, a suitable base plate is provided on which two
bevel wheels are mounted in suitable bearings rotating on a common axis. One
of these bevel wheels is mounted on a short shaft mounted in a suitable bearing
and provided outside the said bearing with a crank or other means for rotating
it. This shaft I call the driving shaft. The other bevel wheel is supported on its
own hub which is made of sufficient length to extend through the bearing.
Intermediate between said bevel wheels is located a shaft at right angles to and
passing through the axis of said bevel wheels. This shaft which I call the
driven shaft is supported in suitable bearings on the base-plate. Loose on the
driven shaft is a bevel wheel gearing with both of the other bevel wheels. Thus
rotation of the driving shaft in one direction will cause the rotation of the oppo-
site bevel wheel in the opposite direction.

page_text: Each of the axially arranged bevel wheels is provided with a circular plate
adjustable towards and from their sides, the plate on the bevel wheel on the
driving shaft being provided with a screw-threaded hub which screws into the
said wheel axially and the said wheel is provided with a number of set screws
which bear against the back of the plate to lock it in any desired position relative
to the side of the wheel. Preferably the points of these screws enter depressions
in the back of the plate. The other plate is made adjustable axially by means of
a spring one end of which bears against a collar interposed between the bearing
and said spring. and a nut screwed on to a stud carried by the plate and extending
axially through the hub of bevel wheel, the said stud being free to slide endwise
through the hub of the bevel wheel. A number of short studs are located on the
plate which enter suitable holes in the bevel wheel and prevent the rotation of
said plate independently of the said wheel, and furthermore, together with the
central stud, serve as guides for said plate in its movements relative to the side
of the bevel wheel.
On the driven shaft is mounted a disc adapted to slide endwise thereon and
to rotate therewith, the endwise movements being imparted to it by any suitable
device such as a forked lever straddling the hub of said disc and engaging the
trunnions of a loose collar on said hub, the lower end of said lever being pivotted
on the base-plate. By swinging this lever in the direction of the length of the
driven-shaft the disc may be moved radially with respect to the plates carried by
the bevel wheels, any suitable device for locking the said lever in any desired
position being provided.
When the disc has been mounted on the driven shaft the set screws in the
bevel wheel on the driving shaft are loosened and turned back, and the plate of
that bevel wheel is then screwed out of the hub of the said wheel until it bears
with the desired force against the edge of the disc on the driven shaft. The
nuts on the central stud of the other plate are then set up to compress the spring
to whatever point may be necessary to produce a pressure of the said plate
against the disc on the driven shaft substantially equal to that with which the
other plate bears against the said disc. The screws in the bevel wheel on the
driving shaft are then turned up into engagement with the plate carried by the
said bevel wheel.
With the parts in this position, the rotation of the driving shaft, will cause
the bevel wheels-through the connection of the intermediate wheel-to rotate
in opposite directions, and as the plates on these wheels bear equally against
opposite points on the edge of the disc on the driven shaft the driving effect on
the said shaft is twice what it would be if the two bevel wheels were not con-
nected by the intermediate wheel. Furthermore, the adjustability of the two
plates toward each other, permits the disc to be gripped between the said plates
with practically equal force from each side thereof and hence the driving shaft
will not be deflected in the slightest degree from a straight line and the running
parts therefore will rotate as freely with the plates set up hard against the disc
as they would if said plates had only a slight frictional engagement therewith.
It is obvious that as the disc is moved towards the centres of the plates the
speed of rotation of said disc will decrease to zero at the true centres thereof,
and a further movement across the centres will cause said disc to rotate in the
opposite direction. It is very desirable however that when the disc reaches a
point near the centres of the plates that the frictional engagement between said
disc and said plates should be interrupted for two reasons,-first, because the
plates would grind against the edge of the disc if the pressure between the parts
were not relieved when the edge of the disc lies opposite the centre of the plates,
and secondly because as the disc approaches the centre of the plates the shortening
of the driving leverage causes more or less grinding action between the contacting
surfaces of the plates and the edge of the disc, if it is made square to obtain the
greatest frictional contact, owing to the thickness of the latter.
For the reasons above stated, the surface of the plates at their centre of rotation

page_text: is depressed so that the driven shaft may be at rest for a certain period as the
disc approaches and passes by the centre of the plates.
It will be understood that it is immaterial whether the gears carrying the
plates be rotated by power applied to one of the bevel wheels as herein before
described or by power applied to the intermediate wheel, in which construction
a slight modification is necessary viz.:-the making of the driven shaft in two
parts, the ends of which abut within the hub of bevel wheel carried by it, the
said wheel being secured to that part of the shaft extending outward through
the bearing, which in effect is the same as allowing the intermediate bevel wheel
to rotate freely on the driven shaft.
Between the collar against which the spring bears and the end of the bearing
and also between the hub of the gear bevel wheel on the driving shaft and the
end of the bearing carrying the said shaft suitable anti-friction balls are pro-
vided to take the thrust of the plates.
BERT E. PHILLIPS, Assoc.M.Inst.C.E., M.I.Mech.E.,
Chartered Patent Agent,
70, Chancery Lane, London, W.C.
Improvements in Frictional Driving Mechanism.
I, ROBERT EDWARD PHILLIPS, of 70, Chancery Lane, London, in the County
of Middlesex, Chartered Patent Agent, do hereby declare the nature of this
invention which has been communicated to me from abroad by Albert H. Overman,
of Chicopee Falls, Massachusetts, U.S.A., Cycle Manufacturer, 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 frictionally driven variable speed devices and it has
for its object the construction of mechanism of this class whereby greater effi-
ciency is attained, and whereby means are provided for the disengagement of the
driving and driven members of the device at a point where the speed of the
driven member is reduced to zero; and a further object of the invention lies
in the construction of means for compensating for the wear of the engaging sur-
faces of the driving or driven members, whereby the member through which
the variable speed is attained may never be subjected to any lateral pressure
which would tend to deflect the axis thereof from a straight line and cause it to
bind in its bearings: And the invention consists in the construction hereinafter
fully described and claimed.
In the accompanying drawing which illustrates one form my invention may
assume.
Figure 1 is a view in plan of a frictional driving mechanism embodying this
invention.
Figure 2 is a view in section thereof on line of Figure 1.
Figure 3 is a view in plan-partly in section-showing a modification of the
construction shown in Figure 1.
Throughout the views similar parts are marked with like letters of reference.
This invention has particular reference to that class of devices in which two

page_text: discs are employed whose axes are located at right angles one to the other, and
the edge of one of which discs bears on the side of the other, which is the driving
member, and is movable radially thereon for the purpose of effecting a varia-
tion in the speed of rotation of the driven member. This construction is old
and is impracticable., except for the transmission of a small amount of power,
because of the fact that the amount of power which can be transmitted through
devices of this kind, depends entirely on the frictional engagement between the
edge of one of said discs with the side of the other. To make this engagement
constant. the driven member has sometimes been located between two discs having
a common axis, one of which discs has served as a driving disc and the other
being idle and spring-pressed toward the said driving disc. Sometimes the
riven-disc is otherwise forced against the driver. Such a construction, of course,
has no advantage in point of efficiency over a construction in which one disc is
pressed against the other by any other means, for but one of the discs is a
driver.
In carrying out this invention, a suitable base plate 1 is provided on which
two bevel gear wheels 2 and 3 are mounted in suitable bearings 4 and 5, for
rotation on a common axis. One of these bevel wheels 2 is mounted on a short
shaft 6 mounted in a bearing 4 and provided outside the said bearing with a
crank 7, or other means for rotating it. This shaft 6 I call the driving shaft.
The other bevel gear wheel 3 is supported on its own hub which is made of suffi-
cient length to extend through the bearing 5. Intermediate between said bevel
gear wheels 2 and 3, is located a shaft S at right angles to, and passing through
the axis of said bevel gear wheels. This shaft which I call the driven shaft is
supported in suitable bearings 9 and 10, on the base plate 1. Loose on said driven
shaft S. is an intermediate bevel gear wheel 11, gearing with both of the other
bevel gear wheels 2 and 3. Thus rotation of the driving shaft 6 in one direction
will cause the rotation of the opposite gear wheel 3, in the opposite direction.
Each of the axially arranged bevel gear wheels is provided with a circular
face plate 12, adjustable towards and from their sides. The plate 12, on the
bevel gear wheel 2, is provided with a screw-threaded hub which screws into the
said wheel axially, and the said wheel is provided with a number of set screws 13,
which bear against the back of said plate to lock it in any desired position relative
to the side of the wheel. Preferably, the points of these screws enter depres-
sions in the back of the plate, as shown in Figures 1 and 3 of the drawing. The
other plate 12 on the wheel 3 is made adjustable axially by means of a spring 14,
one end of which bears against a collar 16, interposed between the bearing 5
and said spring, and the other end against a nut screwed on to the stud 15.
centrally located on said plate and extending axially through the hub of said
bevel gear wheel 3, the latter rotating in its bearings in a fixed plane, and said
stud 15 carrying the plate 12, being movable endwise through said hub.
A number of short studs 17, located on the plate 12, enter suitable holes in
the body of the bevel gear wheel 3, and prevent the rotation of said plate
independently of the said bevel gear wheel, and furthermore, together with the
central stud 15, serve as guides for said plate 12 in its movements relative to the
side of the bevel gear wheel.
On the driven shaft 8 is mounted a disc 18 adapted to slide endwise thereon and
to rotate therewith. Endwise movements are imparted to said disc by any suit-
able device.
In the drawing, the device shown consist of a forked lever 19 straddling the
hub of said disc 18 and engaging the trunnions of a loose collar 20 on said hub,
the lower end of said lever 19 swinging on a suitable pivot on the base-plate 1.
By swinging said lever in the direction of the length of the driven-shaft 8, said
disc 18 may be moved radially with respect to said plates 12.
A suitable device for locking said lever in any desired position is shown in
Figure 2 and consists in a slotted curved arm 21 provided with a bolt and thumb
nut 22, passing through a slot in said lever 19.

page_text: When the disc 18 has been mounted on the driven shaft 8, the said screws 13
of the bevel gear wheel 2 are loosened and turned back, and the plate 12 of that
bevel gear wheel is then screwed out of the hub of the said wheel until it bears
with the desired force against the edge of said disc.
The nuts on the central stud 15 are then set up to compress the spring 14 to
whatever point may be necessary to produce a pressure of the plate 12 on the
bevel gear wheel 3, against the disc 18, substantially equal to that with which
the plate on the bevel gear wheel 2 bears against it. The screws 13 are then
turned up into engagement with the plate 12 on the bevel gear wheel 2.
With the parts in this position, the rotation of the driving means, as the
crank 7, for example, will cause the bevel gear wheels 2 and 3, through the
connection of the intermediate bevel gear wheel 11,-to rotate in opposite direc-
tions, and as the plates 12 on these gear wheels bear equally against opposite
points on the edge of the disc 18, the driving effect on said disc is twice what
it would be if the two bevel gear wheels 2 and 3, were not connected by the
intermediate bevel gear wheel. Furthermore the adjustability of the two plates 12
toward each other, permits the disc 18 to be gripped between the said plates with
practically equal force from each side thereof, and hence the driving shaft 8
will not be deflected in the slightest degree from a straight line, and the running
parts therefore, will rotate as freely with the plates 12 set up hard against the
disc as they would if said plates had only a slight frictional engagement therewith.
It is obvious that as the disc 18 is moved towards the centres of the plates 12,
the speed of rotation of said disc will decrease to zero at the true centres thereof,
and a further movement across the centres will cause said disc to rotate in the
opposite direction.
It is very desirable, however, that when the disc 18 reaches a point near the
centre of the plates 12 that the frictional engagement between said disc and said
plates should be interrupted for two reasons, first, because the plates 12 would
grind against the edge of the disc, if the pressure between the parts were not
relieved when the edge of the disc lies opposite the centre of the plates, and,
secondly because as the disc approaches the centre of the plates, the shortening
of the driving leverage causes more or less grinding action between the contacting
surfaces of the plates and the edge of the disc owing to the thickness of the
latter.
If the edge of the disc were rounded, this grinding action would not take
place.
For the reasons above stated, the surface of the plates 12 about their centre
of rotation is depressed, as shown at 23, to the end that the driven-shaft 8 may
be at rest for a certain period as the disc 18 approaches and passes by the centro
of said plates.
It will be understood that it is immaterial whether the bevel gear wheels 2
and 3 carrying the plates 12 be rotated by power applied to one of said bevel
gear wheels or by power applied to the intermediate bevel gear wheel 11.
Figures 1 and 2 of the drawing show the power applied to the wheel 2, which
is the preferred method, but in Figure 3 the power is shown applied to the
wheel 11.
This change requires but a slight modification of the construction, viz.:-the
making of the driven shaft 8 in two parts, the ends of which abut within the
hub of said bevel gear wheel 11, the latter being secured to that part of the shaft
extending outward through the bearing 9, and having a crank or other suitable
means thereon for rotating it.
This, in effect, is the same as allowing the intermediate bevel gear wheel 11,
to rotate freely on the driven-shaft 8, as shown in the other figures. In all other
respects, the constructions are the same.
Between the collar 14 and the end of the bearing 5, and between the hub of the
wheel 2 and the end of the bearing 4, suitable anti-friction balls 24, are provided
which take the thrust of the plates 12.

page_text: 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: -
(1) The combination in a frictional driving mechanism, of two driving bevel
gear wheels rotatable in parallel planes on a common axis, an intermediate bevel
gear wheel in mesh with both of said driving bevel gear wheels, face plates on the
contiguous sides of said driving bevel gear wheels, a shaft and a disc thereon
located between said plates and rotatable in a plane at right angles thereto, and
in frictional contact therewith, and means for adjusting one of said face plates
towards and from the other, whereby their frictional contact with said disc may
be increased or diminished, and means whereby the driving bevel gear wheels
may be rotated, substantially as described.
(2) In a frictional driving mechanism, two driving bevel gear wheels rotatable
on a common axis, an intermediate bevel gear wheel in mesh with both of said
driving bevel gear wheels, a circular plate adjustably supported close to the con-
tiguous sides of each of said driving bevel gear wheels, a shaft and a disc thereon
supported between said plates in contact therewith, and adapted to rotate in a
plane at right angles thereto, combined with means for moving one of said
plates positively and the other yieldingly against said disc substantially as
described.
(3) In a frictional driving mechanism, two bevel gear wheels rotatable in
parallel planes, a circular plate supported close to the contiguous sides of each of
said wheels, adapted to rotate therewith and movable axially relative thereto,
a shaft and a disc thereon supported between said plates, the periphery of which
is in contact with the latter, combined with means for moving said disc on said
shaft diametrically of said plates, said plates having means for interrupting the
contact of the disc and plates at and near the centre of the latter, substantially
as described.
(4) In a frictional driving mechanism, two driving bevel gear wheels rotatable
in parallel planes, a shaft located midway between the contiguous sides of said
bevel gear wheels and at right angles to and in the same plane as the axis of
said driving bevel gear wheels, an intermediate bevel gear wheel loose on said
shaft and in mesh with both of said driving bevel gear wheels, a disc on said
shaft rotatable therewith and movable lengthwise thereon, a circular plate sup-
ported on the contiguous sides of each of said bevel gear wheels and adapted to rotate
therewith, and to be moved toward each other into contact with the periphery
of said disc combined with means for moving said disc on said shaft diametrically
of said plates, said plates having means for interrupting the contact of said
disc with said plates at and near the centre of the latter substantially as described.
(5). The improved frictional driving mechanism constructed, arranged and
adapted to operate substantially as hereinbefore described and shown with refer-
ence to Figures 1 and 2 of the accompanying drawing.
(6) The improved frictional driving mechanism constructed, arranged and
adapted to operate substantially as hereinbefore described and shown with refer-
ence to Figure 3 of the accompanying drawing.
Doted this th
1000
BERT E. PHILLIPS, Assoc. M. Inst.C.E., M.I.Mech.E.,
Chartered Patent Agent,
70, Chancery Lane, London, W.C.
ROBERT E. PHILLIPS, Assoc. M.Inst.C.E., M.I.Mech. E.,
Chartered Patent Agent,
70, Chancery Lane, London, W.C.