Improvements in or relating to Driving-gear for Cycles and other Vehicles.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in or relating to Driving-gear for Cycles and other
Vehicles.
I, HEINRICH EHRHARDT, of 20, Reichs Strasse, Düsseldorf, Germany, Civil Engineer,
do hereby declare the nature of this invention to be as follows:-
This invention has for object to provide simple driving-gear and means whereby
the speed of travel of vehicles can be easily altered. The driving-gear of a bicycle
according to this invention comprises a hollow shaft that carries two pin-wheels
("Ritzel") of which one is fixed on the said shaft whilst the other has a feather-
and-groove connexion therewith. On the adjacent crank is fastened a ring which is
provided with an inner and an outer circle of teeth, the teeth of one ring being
preferably directed towards those of the other ring, and is so constructed that the
movable pin-wheel can, by simply shifting it on its shaft, be brought into engagement
with the inner or the outer teeth of the toothed ring, whereby the ratio of transmission
will be altered. In order to fix the movable pin-wheel in its position for the time
being in relation to the toothed ring there is screwed to it a spring which, after the
pin-wheel has been shifted, enters a recess in the shaft and prevents the pin-wheel
from being shifted further. The fixed pin-wheel engages in a disc which is placed
on the wheel-hub or is connected in any other way with the wheel to be driven.
Instead, however, of a single movable pin-wheel having pins of round cross section
or of ordinary breadth, there may be provided a single pin-wheel having broad pins
or teeth, or two pin-wheels located on a single shaft, with the object of reducing the
movement necessary when putting the hollow shaft into or out of gear with the toothed
ring and consequently rendering the engagement and disengagement as gentle as
possible.
As an alternative the ring on the crank may be provided with two circles of round
pins instead of teeth, the wheel or wheels engaging therewith being formed with
teeth the teeth of one circle preferably being directed towards those of the other.
The change of speed is effected as in the above described construction by shifting the
pin wheel or wheels on its or their shaft, but in this case the amount of shifting
required is not greater than double the thickness of the pins of the ring. The
wearing of the pin-wheel, moreover, is considerably reduced by giving it broad
teeth.
The pin-wheel, again, may be formed as a drum or barrel wheel and in this case
may have teeth on the two end faces, these teeth being adapted to lie within the
two tooth or pin circles or rings.
For changing the transmission-ratio there may also be employed an arrangement
with which, without being obliged to increase the number of rotations of the
driving-shaft, the crank-shaft can, by being put out of gear, be brought completely
disconnected from the driven shaft. This operation is extremely advantageous in
cycling upon inclined ground, as the cyclist, after he has brought the crank-shaft, by
a simple manipulation, out of engagement with the driving-wheel, allows the latter
to run free and can use the cranks conveniently as foot-rests. When necessary, he

page_text: can then easily connect the crank and the driving-wheel with each other and give to
both the desired transmission-ratio. For this purpose there is employed an eccen-
trically mounted gear-shaft which is provided with so called pin-wheels arranged to
be normally in gear with discs which are located on the crank-shaft and the driving-
shaft and are provided with holes arranged in concentric rings, the arrangement being
such that by turning the axis of the gear-shaft about its eccentric pivots the pin-wheels
and their discs can be brought out of engagement and the crank-shaft and driving-
wheel shaft consequently disconnected.
In one construction of this kind the driving-wheel and the driven-wheel have each
a disc that contains holes arranged in circles or rings, the distances apart of these
circles or rings being equal in the two discs. On the sleeves surrounding the crank-
shaft and the driving-wheel shaft there are provided two projections arranged in
such a manner that their connecting line is oblique. In these two projections the
gear-shaft is mounted by means of pins or pivots projecting eccentrically from its
ends. On this gear-shaft there fits so as to be movable thereon a sleeve which carries
at its ends the pin-wheels, which by longitudinally shifting the sleeve can be brought
into engagement with different sets of the concentric holes of the above mentioned
discs. At the crank-shaft end of the gear-shaft there is mounted concentrically to
the corresponding pivot a small toothed wheel which is in engagement with a worm
or rack arranged on the end of an upright regulating-rod.
When the crank-shaft and the driving-wheel shaft are connected together and it is
desired to disconnect them, all that is necessary is to turn or press down the regu-
lating rod, which is provided with a handle. The worn or rack will then rotate the
toothed wheel with which it is in gear and also the eccentrically mounted shaft,
which will then assume a position in which the pin-wheels will be out of engagement
with the discs and the driving-wheel will consequently be completely independent of
the crank, which will be inoperative, so that the driving-wheel can move freely and
the cranks can conveniently be used as foot-rests. If, now, it be desired to put the
crank into engagement with the driving-wheel shaft again and an alteration of
the transmission ratio be necessary, then the sleeve provided with pin-wheels will be
shifted longitudinally by means of a suitable device and the gear-shaft will be brought
into its original position by pulling the regulating-rod.
The putting into and out of gear of the pin-wheels may, with this construction,
also be effected in a manner usual in old lathes.
The eccentrically mounted shaft may have one of its pivots prolonged and provided
with a sleeve furnished with a handle and acted upon by a spring for engaging it or
keeping it engaged, by means of lugs, with the bearing of the pivot when the
shaft is in a suitable position of engagement or disengagement.
In some cases there may be on the crank and the driving-wheel shaft simply
two rings or wheels each having a single circle of holes and the connecting shaft
may have simply two pin-wheels, no means being provided for disconnecting the
crank shaft from the driving-wheel or for varying the transmission-ratio.
Dated this 31st day of July 1897.
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in or relating to Driving-gear for Cycles and other
Vehicles.
I, HEINRICH EHRHARDT, of 20, Reich Strasse, Düsseldorf, Germany, Civil Engineer,
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:-
This invention has for its object to provide simple driving gear for cycles and other
vehicles and means whereby the speed of travel of such vehicles can be easily altered
to suit requirement.
According thereto I construct driving gear for cycles and other road vehicles as
I shall now describe with reference to the accompanying drawings which show my
invention applied, by way of example to a safety bicycle.
Fig. 1 is a sectional plan view of one arrangement of driving gear according to this
invention suitable for a bicycle ;
Fig 1 is a cross section on the line x x of Fig. 1 &
Fig. 2 shows a detail of such gear,
Figs. 3, 4, 5, and 6 are sectional plan views showing modified forms of the
driving-gear.
Figs. 7 and 8 show respectively in side view and sectional plan view, another
modification.
Figs. 9 and 10 are similar views to Figs. 7 and 8 respectively showing another
construction of driving gear according to this invention.
Fig. 11 is a similar view to Fig. 10 but showing some of the parts adjusted to a
different position.
Figs. 12 and 13 show in side view and sectional plan view respectively, a further
modified arrangement of the improved driving gear.
On
The driving gear shown in Figs. 1, 2 and 3 comprises a hollow shaft a which forms
part of the connection between the crank axle of the bicycle and the rear driving
wheel. This shaft which may be mounted in suitable ball bearings carried by the
frame work of the machine, has fixed to its rear end a toothed wheel b and on its front
end is provided with an endways movable toothed wheel c. The said hollow shaft is
made hexagonal at the part where the toothed wheel cis novably mounted thereon,
(see Fig. 1) so that such wheel can slide endways but cannot turn on the shaft.
one end of the crank axle A, or, as shown, on the inner side of one of the pedal cranks d,
are fixed two concentric rings of teeth e, e¹ these rings being so arranged (as shown)
that the toothed wheel c can, by simply sliding it along the hollow shaft a, be moved
into gear with either of the said rings of teeth and thereby enable the ratio of trans-
mission between the crank axle A, or crank d, and the rear wheel driven therefrom to
be readily varied. For the purpose of fixing the toothed wheel c in position for the
time being relatively to the ring of teeth e or e¹ there may be used a spring blade
screwed or otherwise fixed to the hub of the wheel c and provided with a pin f, which,
after the toothed wheel has been moved endways sufficiently, enters a suitably
arranged hole or recess in the hollow shaft a, and thereby fixes the toothed wheel c in
its adjusted position on the shaft.
The toothed wheel 6 fixed on the other end of the hollow shaft a, gears with a
wheel that is fixed on the hub of the driven or rear wheel B (Fig. 8) and consists
of a disc formed with an annular row of holes g¹ (Fig. 7) in which the teeth of the
wheel b work. The said rear wheel B which is mounted to rotate about the rear
axle B¹, is thus rotated from the pedal crank or crank shaft by means of the hollow
shaft a and the toothed wheels cand b carried thereby.

page_text: In Fig. 1, the two rings of teeth e, e¹ which are shown fixed on the crank d, are
made in one piece.
In the modified construction shown in Fig. 3, the two rings of teeth e, e¹ are made
in two separate parts, viz., one part provided with a ring of internal teeth e, and the
other part with a ring of external teeth e¹. Both rings of teeth are arranged con-
centrically to the axle A and to each other.
In order to reduce to a minimum the movement of the toothed wheel c between
the two rings of teeth, and also in order to effect the engagement and disengagement-
with the greatest possible smoothness, the toothed wheel c may be made wide, as
shown in Fig. 4. This object may also be attained by using a double toothed
wheel c c as shown in Fig. 5, instead of a single toothed wheel c as shown in the
previous figures, the two toothed wheels cc constituting the double toothed
wheel, being firmly connected together so that they move simultaneously as one
body.
'J
.
Fig. 6 illustrates a modification of the arrangements shown in Figs. 1 to 5 inclu-
sive. In this case the teeth in the two rings of teeth e and e¹ are formed of round or
conical pins which engage with the teeth of a drum wheel, having two rings of
teeth carranged to face each other, and adapted to gear with the rings of
teeth e, e respectively as shown with respect to the rings of teeth c, e in Fig. 6. The
drum wheel c c¹ is formed on its hub with a tubular projection or extension c² by
means of which it can be moved to and fro on the shaft a from the seat of the rider
by means of a suitable arrangement of levers. With this construction when the
outer toothed wheel c is in engagement with the outer ring of teeth e, the greater
speed of the rear driving wheel can be attained, and vice versa, when the ring of
teeth c¹ is in engagement with the ring of teeth e, a smaller speed can be obtained.
The change of speed is effected in the arrangement shown in Figs. 4, 5 and 6
similarly to that shown in Figs. 1, 2 and 3 by shifting the wheel c or wheels c, c¹ on
its or their shaft, but in these cases the amount of movement in the adjustment need
not be greater than double the thickness of the pins or teeth on the ring. The
wearing of the gear wheel moreover is considerably reduced by giving it broad
teeth.
In Figs. 7 and 8 the double toothed wheel c c is constructed by cutting the teeth
in the projecting ends of a cylindrical surface the double toothed wheel thus formed
being mounted to move to and fro between the two rings of teeth e and e¹, as required.
The mode of operation of this arrangement is the same as that of the arrangement
shown in Fig. 6.
In the arrangement shown in Figs. 9 and 10, the ratio of transmission between
the crank axle and the rear wheel is changed in a different manner to that described
with reference to the preceding arrangements. On the crank axle A is fixed a disc l,
and on the axle of the rear driving wheel is fixed another disc 1, each of these two
discs being provided with two concentric circles of holes (see Fig. 9), the radial
distance between the two circles of holes being the same in both discs. The
transmission of motion from the perforated disc on the crank axle to the perforated
disc on the rear driving wheel axle, is effected through a hollow shaft o which is
arranged to rotate on a shaft m (see Fig. 10) which is mounted at its two ends in
bosses on the frame of the bicycle by means of eccentrically arranged pins and n².
These pins are so arranged at the respective ends of the shaft m as to be about 180°
apart. The hollow shaft o, which is capable of being moved to and fro in a longitudinal
and
P
.direction on the shaft m, has fixed to its ends toothed wheels
arranged at such a distance apart that when the toothed wheel p engages with the
inner circle of holes in the disc l, the toothed wheel q will engage with the outer
When
circle of holes in the disc ¹. This position is illustrated in Figs. 9. and 10.
the hollow shaft o is moved in the direction of the rear wheel, the toothed wheel q can
with
be engaged with the inner circle of holes in the disc ', and the toothed wheel
the outer circle of holes in the disc l. In order that the hollow shaft, together with
the toothed wheels p and q, may be moved endways as described it is necessary, first, to
bring the toothed wheels p and q out of engagement with the respective perforated
g
which are

page_text: discs and V. This is effected by means of the above mentioned eccentrically mounted
pins n and n¹, whereby, if the inner shaft m be rotated about these pins to a suitable
extent, the wheels P and will be brought out of engagement with the perforated
discs, as is clearly shown in Fig. 11. When this has been done the hollow shaft o
with the wheels p and q can be moved endways that is to say, in the present case,
(Fig. 11) towards the axis of the rear wheel. When this has been done, the shaft m
is turned back again whereupon the toothed wheels p and q will be caused to engage
with the other rows of holes in the respective perforated discs (viz. the wheel p with
the outer row of holes in the disc and the wheel q with the inner row of holes iu
the disc . In this way the ratio of transmission between crank axle and the rear
wheel can be readily changed to suit requirement.
In order to readily rotate the shaft o, there is fixed to the pin n and one end of
the shaft m a toothed wheel r which engages with a toothed rack 8 on the end of an
upright regulating rod s¹ which is capable of being moved up and down in a vertical
direction by means of a bandle s². The handle is arranged to be operated from
the rider's seat so that the wheels p and q can be disengaged from the respective
perforated discs whilst the bicycle is travelling. The shifting of the shaft o in the
longitudinal direction for the purpose of causing the wheels p and q to move from a
position opposite one set of holes in the discs, to a position opposite to the other
set of holes in the said discs, can also be effected by means of toothed racks adapted
to be actuated by means of a suitable handle from the rider's seat, so that the rider
is enabled to vary the ratio of transmission between the crank axle and the rear.
driving wheel whilst travelling.
The improved arrangement hereinbefore described has also the further
advantage that the rider is enabled, when riding down hill, to throw the wheels p
and q out of operation, as indicated in Fig. 11, for the purpose of thereby bringing
the crank axle out of connection with the driven axle. In this case the rider can
utilize the pedals of the crank axle as foot-rests, because they will not then share in
the rotary motion of the rear wheel. When the rider has arrived at the bottom of
a hill he can readily move the wheels p and q back again into engagement with
the perforated discs and , whereby transmission is again re-established between
the crank axle and the rear driving wheel.
In the arrangement shown in Figs. 12 and 13, the perforated dises and have
each three annular rows of holes. Also the rotation of the hollow shaft o with the
wheels p and q is not effected from the rider's seat, but the eccentric pin n carries
an extension m¹ and is rotated by means of an endways movable hand-wheel n³, so that
thereby the entire shaft o is capable of executing a rotary movement of 180°. The
hand wheel n is connected by a feather and slot connection to the extension m¹ and
is acted upon by a spring m³ for engaging it or keeping it engaged by means of
lugs m³, with the bearing of the pivot when the shaft is in a suitable position.
Having now particularly described and ascertained the nature of the said invention
and in what manner the same is to be performed I declare that what I
claim is :-
1. Driving gear for cycles and other vehicles in which the crank or driving axle
or a part connected thereto carries two spur wheels or rings of teeth namely a large
wheel or ring with internal teeth and a small wheel or ring e¹ with external teeth,
and there is mounted between them a third toothed wheel c, for transmitting the
rotation to the axle to be driven, the arrangement being such that the third toothed
wheel is adapted to be moved to and fro between the two former wheels, and can
thereby be brought alternately into engagement with the larger or with the smaller
toothed wheel or ring of teeth e or el substantially as herein before described with
reference to Figs. 1, and 3 of the drawings annexed.
2. Driving gear of the kind specified in the preceding clain, in which (with the
object of diminishing the movement necessary for putting the toothed wheel c in and
out of gear, and of producing the greatest possible smoothness of engagement and

page_text: disengagement) the wheel c is made wider as shown in Fig. 4 or there is substituted
for it a double toothed wheel c c as shown in Fig. 5:
3. The modified construction of driving gear shown in and described with reference
to Fig. 6 of the drawings annexed according to which the two wheels or rings of
teeth e and e', are formed of conical or similarly shaped pins adapted to gear with a
movable drum-wheel c, c¹ provided with two rings of teeth facing each other and so
ärranged that one of them (c) can be engaged from outside with the larger ring of
teeth e of the crank axle, whilst the other ring of teeth (c¹) of the drum wheel can
be engaged from the inside with the other ring of teeth on the crank axle, the
distance apart of the rings of teeth on the drum wheel being made such that
only one ring of teeth can engage with the adjacent ring of teeth on the crank axle
a's set forth.
4. The modification of the construction specified in Claim 3, in which the drum
wheel is provided at its two edges with rings of teeth, and is capable of being moved
to and fro between the two rings of teeth on the crank axle, substantially as
herein before described with reference to Figs. 7 and 8 of the drawings annexed.
5. In driving gear for cycles and other vehicles the combination with a shaft m
mounted eccentrically by means of pins n n', perforated disc connected to the
crank axle and rear driving wheel respectively, a hollow shaft o mounted to rotate
on and capable of being slidden along the shaft m and toothed wheels and q fixed
to the shaft o and adapted to be engaged with the perforated discs, respectively,
of the means whereby the shaft m can be rotated about its eccentric piñs n n¹ so as
to engage the wheels p and q with or disengage them from the discs and
respectively and hold them in the engaged or disengaged position at will, substantially
as herein before described with reference to and shown in Figs. 9, 10 and 11, or
modified according to Figs. 12, and 13 of the drawings annexed.
Dated this 5th day of January 1898.
For the Applicant,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.
l