Improvements in Driving Gear for Cycles and other purposes.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in Driving Gear for Cycles and other purposes.
I, GEORG HESS, of 35, Rothenburgerstrasse, Nuremberg, in the Empire of
Germany, Manager, do hereby declare the nature of this invention to be as
follows:-
This invention has for its object a driving gear for cycles and the like in which
the chain wheels are mounted eccentrically to the pedal shaft and to the axle of
the rear or driving wheel. By this means the transmission from the pedal shaft
to the front or driving sprocket and that from the driven sprocket or rear wheel
sprocket to the driving wheel itself does not take place on the axle or hub but
almost on the periphery of the chain wheel whereby a favourable proportion of
transfer is attained owing to the favourable point of transfer.
An
Pedal cranks are keyed on the pedal shaft. A disc or ring firmly connected to
or in one piece with the pedal shaft is arranged concentrically to the pedal shaft
and is provided with several rollers on the side facing the pedal crank.
eccentric ring is mounted on the bottom bracket or barrel of the pedal shaft and is
held in place in any suitable manner, for instance by means of screws and a cover-
ing or supporting ring. This eccentric ring is completed by means of a flat ring
screwed onto the same, in such a way that an eccentric is formed thereby which
has on its periphery a V-shaped groove or race for receiving balls. A chain wheel
is arranged around this eccentric and has on its cylindrical inner face a V-shaped
groove or race. The balls thus lie in a race formed by the two V-shaped grooves
in the eccentric and the chain wheel and prevent these latter being pushed one off
the other.
The said chain wheel or front sprocket is provided with curved recesses opening
towards its centre on its inner periphery and facing the roller ring. These arched
recesses are preferably formed on a separate annular piece in order to allow of its
being easily replaced when it becomes necessary to do so through wear. The rollers
on the roller ring are intended to engage in the recesses of the annular piece and
thereby to operate the sprocket on the rotation of the ring by means of the pedal
cranks. One roller is thus always in engagement and the next always comes into.
action before the previous roller has reached the edge of the recess." The action
of the rollers on the chain wheel takes place near the periphery of same.
In order to fix the flat ring of the eccentric a pointer or pivotted pin is screwed
on a spoke of the eccentric, which pin engages in one of a series of fixing holes
provided in the flat ring. If the ball race becomes worn it may be adjusted by
unscrewing the flat ring and then fixing the latter by inserting the pin in a fresh
fixing hole. Of course the fixing of the ring may be effected in any other suitable
manner.
The rear sprocket or chain wheel may be connected in a similar way with the
axle of the driving wheel. In this case however the proportions are reversed and

page_text: the original roller ring is formed as a rear sprocket and the former front sprocket as
the hub of the wheel. The arrangement of the parts on the pedal crank will be
evident from the foregoing. A chain wheel or rear sprocket is mounted eccentri-
cally on the rear wheel axle in such a way that it maintains its position and the
chain wheel always maintains the same position so as to constantly maintain the
tension of the chain. The hub of the wheel is centric to the axle and is operated
by the arrangement herein before described. The transfer to the wheel takes
place however on a larger leverage than was hitherto customary.
This arrangement may either be applied both to the pedal shaft and the rear
wheel axle or only to one of the same i.e. either to the pedal shaft alone or the
rear wheel axle alone. This driving arrangement may also be employed in a
similar way for driving from a shaft by means of chain gearing other shafts which
are to be set in rotation. Other suitable transmission gearing may also be adopted
instead of chain gear. For instance instead of chain wheels bevel wheel gearing
may be adopted.
W. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.
improvешению 10 DIVIgu
I, GEORG HESS, of 35, Rothenburgerstrasse, Nuremberg, in the Empire of
Germany, Manager, 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;-
The cycle driving gear hitherto known with eccentrically mounted gear wheels
operated with internal teeth suffer from the drawback that on the one hand in the
various positions of the cranks the amount of power necessary for an even trans-
mission varies precisely as in the case of direct crank driving and on the other
hand the losses by friction in this arrangement are very considerable as a sliding
friction mainly with toothed gear takes place and the arrangement in most cases
is such that the transfer wheel (chain wheel) cannot run on balls. The arrange-
ments at present known are also frequently complicated in construction and the
transmission is not direct-acting and they are with difficulty accessible for the
purposes of cleaning and repairs.
This invention has for its object a driving gear for cycles and the like in which
the above mentioned drawbacks are removed and which also excels the arrange-
ments at present employed owing to its smaller weight.
In order to diminish the friction, the chain wheel is mounted on balls, and rollers
engage in the internal teeth of the same. The division of the teeth in the internal
set of teeth is a very large one and the number of teeth of the same little or not
at all different from the number of the driving rollers. The action of the driving
roller takes place almost always on the same place of the driving wheel so that
thereby a favourable and equal development of power is obtained. By this means
the result is attained that the proportion of the power applied relative to the
distance covered with regard to the work effected (the product of power and.
<listance) is in a proportion extremely favourable in practice.
This driving gear may be arranged either on the pedals or on the rear wheel
for the transmission of power from the pedal cranks to the front driving sprocket

page_text: ment is shown in the accompanying drawings in several forms of construction;
Figure 1 being a side view of the arrangement on a pedal crank,
Figure 2 a section on the line 1-2 of Figure 1;
Figure 3 a plan view of Figure 1;
Figure 4 shows a diagram of the whole arrangement of the driving gear as
applied to a cycle;
Figure 5 shows a modification in side elevation ;
Figure 6 is a section on the line 6-6 of Figure 5;
Figures 7 and 8 are detail views of the form of teeth employed,
Figure 9 shows another modification in side elevation and
Figure 10 is a section on the line 10-10 of Figure 9.
The arrangement shown in Figures 1-3 is as follows;-
Pedal cranks 66 are keyed on the pedal shaft a. A disc or ring c firmly con-
nected to or in one piece with the pedal crank b is arranged concentrically to the
pedal shaft and is provided with several rollers d (in the present instance six in
number) on the side opposite to that on which the pedal crank b is placed. An
eccentric ring f is mounted on the bottom bracket or barrel e of the pedal shaft a
and is held in place in any suitable manner, for instance by means of screws g
and a covering or supporting ring h. This eccentric ring is completed by means of
a flat ring i screwed on to the same, in such a way that an eccentric is formed
thereby which has on its periphery a V-shaped groove or race for receiving
balls k. A chain wheel is arranged around this eccentric i and has on its
cylindrical inner face a V-shaped groove or race. The balls thus lie in a rake
formed by the two V-shaped grooves in the eccentric fi and the chain wheel
and prevent these latter being pushed one off the other.
The said chain wheel or front sprocket is provided with curved recesses (Figure 1)
opening towards its centre on its inner periphery and facing the roller ring c.
These arched recesses are preferably formed on a separate piece m in order to allow
of its being easily replaced when it becomes necessary to do so through wear. The
rollers d on the roller ring c are intended to engage in the recesses of the annular
piece m and thereby to operate the sprocket on the rotation of the ring c by means
of the pedal cranks. One roller d, as shown in Figure 1, is thus always in engage
ment and the next always comes into action before the previous roller has reached
the edge of the recess. "The action of the rollers d on the chain wheel takes place
near the periphery of same.
In order to fix the flat ring i of the eccentric f a pointer or pivotted pin 2 is
screwed on a spoke o of the eccentric, which pin engages in one of a series of fixing
holes n provided in the flat ring i. If the ball race becomes worn it may be
adjusted by screwing up the flat ring i and then again fixing the latter by inserting
the pin in a fresh fixing hole. Of course the fixing of the ring i may be effected
in any other suitable manner.
In the arrangement shown in Figures 5 and 6 the ring c is replaced by a star
wheel which carries rollers d on its ends. The sprocket has on its inner
side directly the teeth shown in Figure 5 and is mounted in a suitable manner
on the ring g travelling on the eccentric f. The star wheel el engages therefore
directly in the centre beneath the sprocket wheel. This gearing is enclosed by
an annular disc o mounted on the sprocket wheel which disc has an eccentric
recess. The recess of this ring o is then closed in by a second disc p which is
connected to the fixed eccentric by means of a screw q so that the whole arrange-
ment is protected from dust and dirt.
The recesses or teeth of the internally toothed wheels may be of various shapes
instead of being simply semi-circular or arched, the only requisite condition being
that the engagement of the rollers in these recesses will be such as to drive forward
the chain wheel carrying the recesses. The speed of rotation of the chain wheel
For
will therefore be regular or irregular according to the shape of these recesses.
instance the recesses may be so shaped that the speed of rotation of the chain wheel

page_text: with a regular or even driving of the cranks will alter according to the position
of the cranks so that for example the speed of rotation of the chain wheel may be
greater than that of the cranks when the latter are in their highest and lowest
positions, and slower when the cranks are in their mid-positions provided the
chain wheel makes precisely one revolution for each revolution of the cranks, and
that the separate teeth or recesses of the wheel are not equally shaped but are formed
differently in order to attain the object desired.
Figures 7 and 8 show some forms of teeth for such an irregular revolution. For
instance in Figure 8 when the roller d rides on to the edge ¹ in the course of revolu-
tion, the internally, toothed wheel will have its inotion accelerated owing to the
edge forming a greater angle to a radius from the centre of the wheel than
the edge 2, and the extent of this acceleration will depend on the obliquity of
as will be readily understood. In Figure 7 a curved edge is shown instead of the
oblique edge r¹ so that a gradual variation is produced, the acceleration being less
as the roller d approaches the upper end of the recess where the curve more nearly
coincides with the radius than at the bottom.
In the arrangements shown in Figures 9 and 10 the transmission of power from
the pedal cranks to the driving wheel takes place by means of several discs with
rollers which discs stand in compulsory connection with one another, said rollers
engaging in the inner side of the driving wheels, which inner side is provided
with recesses shaped as shown in such a way that always two rollers are in engage-
ment and the crank receives a good guidance. In this case also the transmission
of power from the roller to the driving wheed takes place almost always at the
same place.
A cogwheel u is mounted in the centre of the disc f on a fixed bolt or pin a by
means of ball bearings, in which cogwheel three further cogwheels v vl v² engage, each
of these being displaced 120° the one to another. Of these three cogwheels the
wheel v is firmly mounted on the pedal axle a whilst the two others vl 2 are revolubly
mounted preferably with ball bearings on pins or bolts a a³ formed or fixed on the
disc f. With these cogwheels 12 there are discs www2 formed in one piece
therewith or firmly connected with them, which discs carry rollers 1-9 engaging
in recesses as shown in the chain wheel or sprocket.
The inner side of the sprocket 1, Figure 9, is provided with recesses in which
the rollers 1-9 engage so that the movement imparted to the rollers is transmitted
to the sprocket wheel. The arrangement is also preferably such that two rollers
are always in engagement with the recesses, so that the chain wheel or sprocket
receives a sure guidance. Each roller also remains in engagement until the next
has already engaged with a recess belonging to it.
The recesses are only traversed by the rollers from right to left and the latter
are out of engagement with the former in the centre. so that friction is limited
to the amount necessary for driving and guiding.
,י
The whole driving mechanism is closed in by means of a plate, Figure 10,- so
that it is protected from the action of dust.
If the pedal axle a be set in rotation by means of the pedal crank b the cog-
wheel υ and the disc 20 will share in the said movement. The
cogwheels and 2 and the discs w¹ and 2 are also set in rotation by
means of the intermediate gear u and their circumferential speed is equal to that
of the parts mounted on the pedal axle as the cogwheels uvv & 2 are of equal
diameter. The teeth of the cogwheels are as fine as possible in order to obtain an
easy and quiet running or travel. In the rotation of the discs www2 obtained
in this manner the rollers 1-9 mounted on the said discs engage or act in suc-
cession according to their numbering. After the releasing of an acting roller
the next roller of the same disc passes for guidance into the same recess but quits
the same immediately another guide roller has entered the recess in order not to
increase unnecessarily the friction. The balls & for connecting the chain wheel /
with the eccentric f may be made larger, and a smaller number used with intervals
between each ball, a ring (Fig. 10) being mounted loosely in the groove or ball

page_text: race to keep the balls 'apart, said ring being suitably recessed to receive the
balls.
Instead of (as in the modification shown) three discs being provided with nine
rollers and six recesses, the number of each of these parts may be suitably altered:
The chain wheel carrying the recesses may also, instead of being provided with
teeth for engaging a chain, be formed on its outer periphéry as a toothed wheel or
cogwheel so that this driving arrangement may be made, suitable for chainless
cycles with bevel or face wheel driving gear.
The rear sprocket or chain wheel may be connected in a similar way with the
axle of the driving wheel. In this case however the proportions are reversed and
the original roller ring c or star wheel c¹ is formed as a rear sprocket and the former
front sprocket as the hub of the wheel as shown diagrammatically in Figure 4.
The arrangement of the parts on the pedal crank will be evident from the fore-
going. A chain wheel or rear sprocket r is mounted eccentrically on the rear wheel
axle
in such a way that it maintains its position and the chain wheel always
maintains the same position so as to constantly maintain the tension of the chain.
The hub s of the wheel is centric to the axle q and is operated by the arrangement
herein before described. The transfer to the wheel takes place however on a larger
leverage than was hitherto customary.
This arrangment may either as shown in Figure 4 be applied both to the pedal
shaft and the rear wheel axle or only to one of the same i.e. either to the pedal
shaft alone or the rear wheel axle alone. Any one of the modifications shown may
be arranged on the pedal shaft and the rear wheel independently of that arranged
on the other part. This driving arrangement may also be employed in a similar
way for driving from a shaft by means of chain gearing other shafts which are
to be set in rotation, it being immaterial whether the said shaft be rotated by hand
or by motive power. Other suitable transmission gearing may also be adopted
instead of chain gear. For instance instead of chain wheels bevel wheel gearing
may be adopted which gears with two bevel wheels on each end of a transmission
shaft.
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. A driving gear for cycles and other purposes, characterized by a ring (e) or
star wheel (c) being fixed on the pedal axle and having rollers (d), which engage
in suitably shaped recesses on the inner side of the chain wheel () which is mounted
eccentrically to the pedal axle in such a way that two rollers at the most transmit
the power almost on the outer periphery of the chain wheel in order to drive the
said chain wheel which is mounted by means of ball bearings on an eccentric (f)
and in which arrangement the number of rollers (d) on the ring or star wheel and
the number of recesses in the chain wheel differ little or not at all substantially
as hereinbefore described.
2. A form of construction of the driving gear for cycles and other purposes
herein before described characterized by a disc (f) being eccentrically mounted on
the bottom bracket or nave (e) and having a chain wheel () provided with suitably
shaped recesses on the inner side, arranged on it in ball bearings, on which disc (f)
other discs (www²) compulsorily connected by means of cogwheels (uvv¹²) are
arranged which carry rollers 1-9 which engage in the recesses in such a way that
always one roller is in engagement whilst another simultaneously engages with
a guiding action in the recesses, one of which cogwheels or discs (which are firmly
connected one with another) is firmly keyed on the pedal shaft (a) substantially as
hereinbefore described.
3. The reversal of the driving gear hereinbefore described in such a way that
the chain wheel is arranged in place of the parts mounted on the axle, and said
chain wheel (1) is formed as the rear wheel nave, with the object of rendering this
gearing suitable for transmission to the rear wheel, substantially as described.

page_text: 4. In the driving gear for cycles and other purposes hereinbefore described a
ball bearing for connecting the eccentric (f) with the sprocket or chain wheel (1),
characterized by the arrangement of a small number of large balls (k) which are
held apart by means of a ring (t) loosely mounted in the grooves of the wheel (f
and 7), which ring has suitable recesses at the places at which the balls are inserted,
substantially as described.
Doted this 02nd day of T1 1808
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.