An Improved Two-speed Driving Gear for Cycles and other Pedal Driven Machines.
Year: 1897

page_text: Date of Application, 7th Aug., 1897
Complete Specification Left, 7th June, 1898-Accepted, 6th Aug., 1898
PROVISIONAL SPECIFICATION.
An Improved Two-speed Driving Gear for Cycles and other Pedal
Driven Machines.
I, ALFRED WILLIAM BEVIS, Engineer, residing at Brunswick Villa, Malvern
Road, Acocks Green, in the County of Warwick, do.hereby declare the nature of
this invention to be as follows:--
This invention pertains to the driving mechanism of cycles and other pedal
driven machines, and consists in an improved construction of driving gear which
will allow of differential speeds being obtained, one for hill climbing or to be used
against a strong head wind, and another as a high gear for level roads when
pedalling is easy.
The invention has been chiefly considered in connection with existing chain
driven cycles, and its application is such as not to materially add to their weight
or increase their tread. The improved gear, as aforesaid, is put into and out of
action in a very simple manner, either from the handle bar or from underneath
the saddle pillar; the work required being to either lock or release, from the cycle's
frame, a driving toothed wheel.
The improved driving gear is fitted to the bottom bracket axis, and is character-
ised by the following component parts. A driving toothed pinion, preferably
having an enlarged concentric collar, is loosely mounted upon the bottom bracket
axis, to work against the end face of the bottom bracket; the disposition of the
driving pinion being outwards of the collar. The last named part is provided to
engage a sliding bolt working transversely underneath the bottom bracket, or to be
clamped by a band brake, or its equivalent, for the purpose of arresting and holding
stationary the driving pinion as if in one piece with the bottom bracket.
Gearing with the teeth of this driving pinion are a number of small pinions
preferably four in number) carried, free to rotate, by a driving disc or plate made
fast with one of the driving cranks. These small toothed pinions also gear with
an inside toothed annulus formed upon the ordinary driving chain wheel, and
constitute intermediate gear between the said chain wheel and the driving pinion
before described. The circumference or periphery of the driving disc or plate is
formed with ratchet teeth, and with these engage a pawl jointedly carried upon
the face of the chain wheel; the latter being loosely supported round the bottom
bracket axis in a suitable manner. As before described the driving pinion is
loose upon the bottom bracket axis, and so also is the driving chain wheel, but
the driving crank and the disc or plate carrying the intermediate pinions are fast
upon the axis.
In such a gear the driving chain wheel is of such a diameter as to constitute,
when driving ordinarily, the low speed or power gear. The driving pinion and
the whole of the parts at this time rotate as one, the intermediate pinions being
idle and only forming connection links between the driving pinion and the chain
wheel.
To increase the speed the driving toothed pinion is locked, either by the bolt or

page_text: "
band brake, rigid with the bottom bracket, in which case the intermediate pinions
roll round the driving pinion's periphery like to a sun and planet" movement,
and communicate increased speed to the chain wheel; the latter at this period
running in advance of the driving crank.
So far it has been found practical to lock the driving pinion to the bottom
bracket by a bolt, holes being arranged in the collar to receive the bolt's end, but
the same can be effected in many ways, as also can the ratchet connection between
the driving disc and the driving chain wheel.
This gear, as described, practically all concealed, and properly fitted it would
be impossible to know, without a minute examination, that anything was fitted
other than the ordinary driving mechanism.
1
W. P. THOMPSON & Co.,
Of 11, Burlington Chambers, New Street, Birmingham,
Agents for Applicant.
An Improved Two-speed Driving Gear for Cycles and other Pedal
Driven Machines.
I, ALFRED WILLIAM BEVIS, Engineer, of Brunswick Villa, Malvern Road, Acocks
Green, in the County of Warwick, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement: -
66
33
This invention relates to the driving mechanism of cycles and other pedal driven
machines, and its object is to provide a compact two-speed change gear combined
with novel mechanism for effecting the desired changes, so that one speed can be
used in hill climbing or against strong head winds, and the change rapidly and
efficiently effected to the other speed used for level roads where pedalling is easy.
The invention consists generally in applying within the chain wheel upon the
pedal axle a compact form of that type of gear known as sun and planet'
preferably arranged with a pinion rotating loose upon the spindle gearing by
planet wheels carried upon a disc attached to the crank which in turn gear with
internal teeth cut upon the inner portion of the chain wheel, and the differential
action of these wheels is controlled by simple and efficient devices for causing the
gearing to revolve as a whole, or to revolve only in part to produce the desired
change in speed.
The means adopted to carry the invention into effect are illustrated in the
accompanying sheets of drawings as follows:-
-
Figures 1 and 2 are respectively side elevation and transverse section of the gear
as applied to a cycle.
Figure 3 is a side elevation of the same gear with a modified controlling device.
Figure 4 is a side elevation of the same gear, with another modification of the
controlling device.
Referring to Figures 1 and 2 of the drawings the crank spindle A is mounted
in ball bearings B wituin the bottom bracket C of the cycle, and it has keyed or other-
wise rigidly attached to it a disc plate E. A toothed pinion F is mounted preferably
upon ball bearings G as shown, and runs loose upon a sleeve extension of the
plate E, and this pinion at one side thereof is constructed with a flange such as H
arranged with openings or perforations so placed relatively to similar openings or
perforations in a flange carried by the bracket or other stationary portion of the
machine, that a bolt or bolts J can be used to rigidly connect the two together

page_text: when so desired. The bolt J is operated by hand, and may be firmly held in its
case either in the locked or unlocked position by any convenient means.
Concentric with the disc E is the chain wheel K having an inner toothed
periphery L and mounted by suitable flanges M, N, upon ball bearings. Planet
wheels preferably four in number run loose upon pins P carried by the plate
disc E, and these planet wheels intermesh on opposite sides respectively with the
internal teeth L of the chain wheel, and the external teeth of the pinion F as clearly
shown in Figure 1. On one side of the chain wheel K a ratchet wheel Q is formed,
and gearing within this ratchet is a spring pawl R preferably pivoted at S upon
the pedal crank T, and the teeth of the ratchet and pawl face are in such a direction
that the forward movement of the crank tends to keep the pawl in gear
The operation of the hereinbefore described mechanism is as follows;-When the
slow speed is desired the bolt J is slid back into its corresponding recess on the
machine allowing the pinion F to revolve loose. The crank T being propelled
forward by its pedal causes the pawl R to gear with the ratchet teeth Q, and actuate
the chain wheel, the remainder of the gearing revolving at the same speed, because
the disc E also attached to the crank carries the planet wheels O round at the same
speed,
When it is desired to employ a high speed the bolt J is shot into position so
as to key the pinion F to the bracket or framework. The crank propels the disc E
at its own speed as it is rigidly attached to it, and this causes the chain wheel K
to be propelled not only by the planet wheels O as drivers, but also to obtain an
increased speed owing to the individual rotation of these drivers caused by the
stationary pinion F. The advantage of the special pawl form of coupling R and Q
is now evident, as the speed of the chain wheel exceeds that of the pawl which
therefore simply slips. By thus coupling or uncoupling one positive device such
as J, the other permissive arrangement such as the pawl K, automatically actuates
the gear or not as the case may be.
Figure 3 of the drawings illustrates the same change gear (similar letters.
denoting similar parts) with a modified arrangement of the permissive drive. In
this case no ratchet wheel and pawl is employed, but two or more recessed inclined.
plane holders U are attached to the plate disc E and contain within them steel
or like metal balls V. The recess within the holders U is so arranged and placed
relatively to the teeth L that the forward rotation of the disc plate E causes the
ball to travel up the inclined plane and key the said disc E to the chain wheel K
by jamming in the position clearly shown in the drawings. It is evident that
during the slow speed the ball V will maintain the driving position, but during
the fast speed as the chain wheel K would be travelling faster in the same direction
than the disc E the ball would drop down into the recess at the foot of the
inclined plane.
A gearing giving the same speed-ratio of crank and chain wheel is illustrated in
side elevation in Figure 4 of the drawings (similar letters indicating similar parts)
but in this instance the pawl and ratchet R and Q shown in the first modification,
and the recessed holders U shown in the second modification are replaced by another
device. The spindles P of the planet wheels 0 carry upon them a cam shaped
collar W upon whose outer circular periphery the wheels revolve. Within the
wheel suitable pockets X, X, of the shape shown in the drawing are arranged, and
steel or other balls Y are placed within these pockets. When the gear is on the
slow speed the balls lie in the parts of the pocket adjacent to the depressions in
the cam W as shown keying or jamming the wheel against rotation; but when the
gear is put upon the fast speed the rotation of the planet wheels cause the balls Y
to travel into the outermost portions of the pockets X, thus allowing the planet
wheels to revolve and give the additional speed to the chain wheel.
It is to be understood that the bolt device of attaching the pinion F to the hub
of the machine when desired may be replaced by any equivalent device, such as
clamping by a band brake or friction clutch, and further that this device may be

page_text: operated from the handle bar or from beneath the saddle pillar as desired, and all
without departing from the subject of the present invention.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:-
1. In a two-speed driving gear for cycles and other pedal driven machines
employing a "sun and planet" motion, the combination of a locking device for
the central pinion and means for connecting the crank with the chain wheel so as
to allow the chain wheel to move ahead substantially as hereinbefore described.
2. In two-speed gear for cycles and other pedal driven machines employing a
sun and planet" movement: the operation of the chain wheel by a pawl upon
the crank when at the low speed, so that the said pawl permits the chain wheel
to revolve at a greater speed than the crank when the gear is upon the high speed,
substantially as herein before described with reference to Figures 1 and 2 of the
accompanying drawings.
3. In two-speed driving gear as claimed in Claim I, the operation of the chain
wheel by a ball and inclined plane keying the disc attached to the crank to the inner
periphery of the chain wheel when at the low speed so that the said ball and plano
permit the chain wheel to revolve at a greater speed than the crank when the
gear is upon the high speed, substantially as hereinbefore described with reference
to Figure 3 of the drawings.
4. In two-speed driving gear as claimed in Claim I, operating the chain wheel
directly through a cam or cams carrying the planet wheels at the low speed, the
said cam or cams having pockets and balls disposed about their periphery in such
a manner that at the high speed the planet wheels revolve substantially as herein-
before described with reference to Figure 4 of the accompanying drawings.
Dated this 7th day of June 1898.
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents.