AN EXPANDING COG OR CHAIN WHEEL FOR VARYING THE SPEED OF VELOCIPEDES APPLICABLE ALSO TO OTHER PURPOSES
Year: 1884

page_text: I WALTER GEORGE FREDERICK WEBSTER of No 34 Tontine Street, Folkestone,"
in the County of Kent Engineer, do hereby declare the nature of my said invention
for "AN EXPANDING COG OR CHAIN WHEEL FOR VARYING THE SPEED OF
VELOCIPEDES APPLICABLE ALSO TO OTHER PURPOSES," to be as follows:―
As my invention can be applied to any purpose where a change of speed is
required & as such applications may vary the details of its construction, I will
confine my description to it as applied to driving Velocipedes for which it is
specially applicable. In fitting my expanding wheel to these machines I usually
employ but one such wheel & place it on the crank axle, using any ordinary chain
wheel on the main axle & employing an idle pulley to take up the slack of the
chain, though it is obvious that by using an expanding wheel on each axle
& working them in equilibrium the chain would never become slack, & consequently.
the idle pulley would not be necessary.
.
My expanding wheel is constructed as follows:-Keyed on the crank axle is
a disc in which are fitted 4 or more slides free to move radially, these slides may
be made of any convenient shape though I prefer to make them round. Ou these
slides outside the periphery of the disc are fixed segments which form the
foundation for the rim of cogs or teeth, & they are each struck from a radius
which is a mean between the greatest & least diameter to which the wheel may be
expanded or contracted. Mounted loosely on the crank axle on each side of the
fixed disc are two discs which I call the manipulating discs, each provided at its
periphery with a ring of teeth so that each forms a bevel wheel. Mounted on the
fixed disc is a bevel pinion which gears the bevel wheel discs & forms a kind of
balance gear for a purpose that will presently be made clear. On the inner face of
one of these manipulating discs is cut a spiral cam in the form of a screw. Teeth
cut on the side of the radial slides take into the grooves of this cam so that if the
cam which is part of the manipulating disc is held fast while the fixed disc revolves,
the slides, will move in or out accordingly as the spiral cam is right or left handed.
Supposing the cam to be cut so that the slides move out, i,e, so that the wheel
expands, when the manipulating disc with the cam is held fast and the fixed diso.
forming the wheel moves forward; then when it is desired to contract the wheel
it would be necessary to move the fixed disc backwards, i,e, to back pedal, if the

page_text: manipulating disc with the cam were still held fast; but as this could only be done
on "clutch action" machines, I provide the other manipulating disc (without
a cam) & the balance arrangement between them as before described, the effect of
which is, that if the manipulating disc with the cam is released & the other one
held whe the fixed disc is moving forward, the manipulating disc with the cam will
move forward twice as fast as the fixed disc, which is equivalent to moving the fixed
disc backwards, when the manipulating disc carrying the cam is held fast. Before
describing the arrangement for operating the manipulating discs I will describe the
construction of the expanding rim of teeth, whereby the uniform pitch of the teeth
is not destroyed.
Connected to each of the radial slides as before mentioned is a segment of
a circle. The periphery of these segments is formed with a slot of the shape of an
inverted T, the width of the vertical part of the slot is equal to the width of the
teeth to be used & the width of the horizontal part is say 3/8 of an inch wider, i,e,
3/16 of an inch each side of the vertical part of the slot, the dept of the horizontal
part of the slot is about 3/2 of an inch. Fitting into this slot is a flexible, band
provided with cogs or teeth, this band is made to fit the horizontal part of the slot
& the cogs or teeth on it stand proud of the extreme periphery of the segments.
This flexible band of teeth may be constructed in any approved manner, but the
simplest, & one that I have proved by experience to be reliable is made of malleable
iron, the band of teeth being cast in a solid rim & after being turned true is cut;
it is then passed through the slot in the segments & is fastened to one of them at
one end, so that when the wheel expands the band of teeth may move through the
slot in the segments & accomodate itself to the increased circumference of the
wheel.
The band of teeth is fixed to one of the segments at its forward end when the
wheel is moving forward, so that when motion is imparted to it, or by it, the pull
is direct from the fixed point. It will be seen however that if the wheel is driven
backwards the tendency would be for the band to buckle up, were it not confined
in the horizontal part of the slot in the segments, which allows the strain to come
upon it without buckling it.
I make the band of teeth so long that when the wheel is at its smallest diameter
the teeth are continuous around the circumference of the wheel, but when it is
expanded there is a gap at one place in proportion to the increased size of the
wheel, when this gap is kept within certain limits it is of no account, but when it
is so long as to interfere with the smooth running of the chain, I cut away half the
width of the band of teeth at each end, & allow it to overlap so that there is
a continuous ring of teeth at all times, though certain of them are only half the
usual width when the wheel is expanded.
It will be obvious that teeth of any pitch may be used, but as I prefer to use the
ordinary tricycle chain, which has a pitch of about 1 inches, I make the pitch of
the teeth on my flexible rim of an inch, so that by expanding the wheel half
a tooth at a time I get double the number of variations of speed that I should if
the teeth were of the same pitch as the chain, as I should then have to expand the
wheel one tooth at a time.
It will be understood that I can use this flexible band of teeth & arrangement of
segments with any system of expanding wheels, for instance I have used it with
that system described in a previous application for a Patent with Provisional
Specification filed by me on the eighth day of January last & numbered 1018.
Having now described the construction of the expanding wheel, I will describe
how it is manipulated by the rider; It will be understood that the wheel must be
expanded to the extent of one tooth or a multiple of that distance at each move-
ment, in order that the uniform pitch of the wheel may not be destroyed.
In the
usual construction of machines the chain is in gear with at lest half the circumference
of the chain wheel; therefore to be on the safe side the alteration of the wheel must
be effected during one quarter of its revolution, ie, that quarter when the part of the
rim of teeth that moves is out of gear with the chain. On each of the manipulating

page_text: plates is fixed one or more stops, & on a convenient part of the frame is fixed
a bracket carrying a slide on which are mounted two pins, fitted with rollers to
reduce friction, one on each side of the expanding wheel. In their normal position
these pins are clear of the stops on the manipulating plates, but by moving the
slide to the right or left one or other of the pins engages with one of the stops on
one of the manipulating plates and prevents its revolution; as however this must
be done during a certain part of the revolution of the wheel, a cam is formed on
each side of the fixed disc, carrying the expanding segments, so as to allow the pins
to come in contact with the stops only at certain periods & to insure the contact
being automatically broken when the wheel has expanded one section; which may
be one, two, or more teeth as desired.
The slide carrying the pins is controlled by the rider by means of a rack
& pinion, or its equivalent, so that the slide may be moved to the right or left, as
it may be desired, to expand or contract the wheel; a suitable dial being provided -
to show what the machine is geared to.
ROBT. ED., PHILLIPS,
Agent for the Applicant.

page_text: COMPLETE SPECIFICATION.
I WALTER GEORGE FREDERICK WEBSTER of No 34 Tontine Street Folkestone
in the County of Kent, Engineer do hereby.declare the nature of my said invention
for "AN EXPANDING COG OR CHAIN WHEEL FOR VARYING THE SPEED OF VELOCI-
PEDES, APPLICABLE ALSO TO OTHER PURPOSES" and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement :—
As my invention can be applied to any purpose where a change of speed is
required and as the details of its construction may vary with onch application
I will confine my description of it as applied to driving velocipedes for which it is
specially applicable. In fitting.my expanding wheel to these machines I usually
employ but one expanding wheel and place it on the crank axle, using any ordinary
chain wheel on the main axle and employing an idle pulley to take up the slack of
the chain, though it is within the scope of my invention to use an expanding wheel
on each axle, when by working them in equilibrium the chain would never become
Black.
In order that my invention may be fully understood I will more fully describe
it with the aid of the accompanying drawings in which similar parts are marked
with like letters of reference.
In the accompanying sheet of drawings Fig 1 is a side elevation of the wheel
expanded. Fig 2 is a side elevation (reverse side to Fig 1) of the wheel contracted
Fig 3 is a half sectional elevation of the wheel expanded and contracted. Fig. 4
is a plan of the flexible rim and segments and Fig 5 is a plan of the one end of
the flexible rim showing the part cut away to allow the ends to overlap.
My expanding wheel is constructed as follows.-Keyed on the crank axle A is
a disc B in which are fitted four or more slides C. C. etc. free to move radially.
On these slides C. C. etc. outside the periphery of the disc B are formed
segments c. c. etc. which form the foundation for the rim of cogs or teeth D and
they are each struck from a radius which is a mean between the greatest and least
diameters to which the wheel may be expanded or contracted. Mounted loosely
on the crank axle on one side of the fixed disc is a disc E which I call the manipu-
lating disc; on the inner face of this manipulating disc E is cut a spiral cam e. in
the form of a scrowl, teeth cut on the side of the radial slides take into the groves
of this cam so that if the cam which is part of the manipulating disc E is held fast
while the fixed disc B revolves, the slides will move in or out and expand or
contract the wheel according as the operating mechanism, which will presently be
described, controls. Before describing the arrangement for operating the manipu-
lating disc I will describe the construction of the expanding rim of teeth whereby
the pitch of the teeth is always kept uniform.
Connected to each of the radial slides C. C. etc. as before mentioned is a
segment c. The periphery of these segments is formed with a slot c¹. Fitting into
this slot c¹ is a flexible band provided with cogs or teeth; this band is made to fit
the horizontal part of the slot c¹ the cogs or teeth on it standing proud of the
extreme periphery of the segments c. c. etc. The flexible band of teeth D after

page_text: being passed through the slot in the segments is fixed to one of them by pins x. x.
so that when the wheel expands the band of teeth may move through the slot in
the segments and accommodate itself to the increased circumference of the wheel,
and the band being fixed to the segments at . . when motion is imparted to it, or
by it, the pull is direct from the fixed point. It will be seen however that if the
wheel is driven backwards the tendency would be for the band to buckle up were.
it not confined in the horizontal part of the slot in the segments, which allows the
strain to come upon it without buckling it.
I prefer to make the band of teeth D so long that when the wheel is at its
largest diameter the teeth are continuous around the circumference of the wheel,
I therefore cut away half the width of the band of teeth at each end as shown by
Fig 5 to allow it to overlap so that there is a continuous ring of teeth at all times,
though certain of them are only half the usual width when the wheel is
expanded.
It will be obvious that teeth of any pitch may be used, but I prefer to use the
ordinary tricycle chain, which has a pitch of about 11 inches; I then make the
pitch of the teeth on my flexible rim 5/8 of an inch, so that by expanding the wheel
half a tooth at a time I get double the number of variation of speed that I should if
the teeth were of the same pitch as the chain, as I should then have to expand the
wheel one tooth at a time.
It will be understood that I can use this flexible band of teeth and arrangement
of segments with any system of expanding wheels, for instance I have used it with
that system described in a previous application for a Patent with Provisional
Specification filed by me on the eighth day of January 1884 and numbered 1018.
Having now described the construction of the expanding wheel I will describe
the operating mechanism. Since filing my provisional specification I have devised
a simpler method of operating it, than the one described therein, but as I do not
purpose laying any claim to any particular mode of operating this wheel I will
describe the arrangement I prefer to use and how it is manipulated by the rider.
It will be understood that the wheel must be expanded or contracted to the extent
of one tooth or a multiple of that distance at each movement, in order that the
uniform pitch of the wheel may not be destroyed. In the usual construction of
machines the chain is in gear with at least half the circumference of the chain
wheel; therefore to be on the safe side the alteration of the wheel must be effected
during one quarter of its revolution, i.e that quarter when the part of the rim of
teeth that moves is out of gear with the chain.
On the manipulating disc E I form a ring of teeth and on the disc B fixed to the
axle I mount a train of small spur pinions one of which gears with the teeth on the
manipulating disc. This forms a mechanical motion that is well known and need
not therefore be described in detail. Mounted on the frame of the machine con-
veniently situated with respect to the expanding wheel is a slide controlled by one
of the handles on this slide is fixed a small spur pinion which may be run in and
out of gear with the train of wheels mounted on the fixed disc B. It will be seon
that this train of wheels revolves round the centre of the axle and is quiescent
unless set in motion. When it is desired to alter the diameter of the expanding
wheel the pinion on the slide is manipulated so as to gear with the train of wheels
as it revolves which will set the train in motion just sufficient to move the expanding
wheel one tooth; and so long as the fixed pinion is set to gear with the train of
wheels so long will the diameter of. the wheel expand or contract one tooth at each
revolution. It will be seen that when the wheel is fully expanded or contracted
the operating mechanisin automatically reverses the action, so that there is no fear
of over contracting or expanding the wheel.
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
First. An expanding chain wheel constructed as herein before described and
shown

page_text: . Secondly. In an expanding chain wheel, the flexible rim or band of teeth
constructed and applied, as and for the purpose hereinbefore described and shown,
or any mere modification thereof.
Thirdly. In an expanding chain wheel, the combination of the expanding
segments and the flexible-rim or band of teeth, as and for the purpose hereinbefore t
described and shown.
1885.
ROBT. ED. PHILLIPS, M.L.M.E.,
Consulting Engineer and Patent Agent,
Royal Courts Chambers,
70, 71 & 72, Chancery Lane, London, W.C.,
Agent for the Applicant.