Improvements in Cycles.
Year: 1895

page_text: Date of Application, 4th Oct., 1895-Accepted, 16th Nov., 1395
Improvements in Cycles.
We, JACOB BERNHEIMER, Merchant, and THEODOR MANGER, Manufacturer,
both of 4 Grüner Markt, Bamberg, in the Kingdom of Bavaria, 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 relates to a cycle constructed in such a manner as to enable the
ratio of the gearing of the chain wheels to be readily varied, and in which the
variation in the tension of the chain produced thereby is automatically regulated,
the ratio of the gearing being varied by means of an adjustable chain wheel
and the tension of the chain being controiled by mechanism operated by either
spring pressure or by compressed air.
In the accompanying drawing which illustrates this invention as applied to a
rear-driving bicycle:-
Figure 1 is a view in side elevation.
Figure 2 is a view in side elevation of the chain wheel.
Figure 3 is a view in section thereof on line a, a, Figure 2.
Figure 4 is a broken view in side elevatiou showing one arrangement of the
tightening device, and
Figure 5 is a similar view of another arrangement of the same device.
Throughout the views similar parts are marked with like letters of reference.
The body proper of the adjustable chain wheel consists of a number of sectors
or segments, in the present case six are shown a, a¹, a², a³, a¹, a³, which are guided
by means of pins in the slots of a disc d keyed on the pedal-crank axle f
against the shoulder e thereon. The toothed segments are held in position by
means of the heads b¹ of the pins 6 screwed into them. The expansion of the
toothed segments in a radial direction is effected by the rotation of a star piece g,
the lugs y, 9, 9, g³, gʻ, g³, of which engage with suitably formed curved portions
of each of the six toothed segments, the arrangement being such that when the
star-piece is rotated, the segments will be raised. It will be understood that in
ancther construction the outermost points of these star-lugs may be fitted with
small rollers or the like to diminish friction. After the body of the toothed.
wheel has been adjusted in its desired position, its star-piece is locked in position
by means of lock-nuts h, h', whereby a backward movement of the segments is
rendered impossible.
The star-piece is further formed with two small holes i to receive the ends of
a forked key for effecting the adjustment. The increase or decrease in the
periphery of the toothed wheel may be readily read off from a scale k which
is provided on one of the toothed segments and over which there oscillates a
pointer fixed to one of the lugs of the star-wheel.
The toothed rim consists of a narrow steel band m which is suitably bent or
curved to form the teeth n. The steel band m is screwed fast at one end to a
toothed segment a, and its other toothless end enters a groove which is situated
under the fixed end of the band m.
On slacking the lock nuts h, h', the segments of the wheel body are automatically
pressed together by the elasticity of the toothed rim m.
On increasing or diminishing the adjustable chain wheel, it is not possible to
avoid varying the tension of the chain and the following device is employed to
automatically take up the slack of the chain. The hind wheel fork o is arranged

page_text: so that one end of it can swing at its point of attachment p to the front part of the
main frame and its lower ends g are shaped to slide on the arc-shaped parts of
the lower stay tubes s, the arrangement being such that the axle of the wheel
extends through slots u in the arc-shaped parts r. The hind fork is also provided
with an arc-shaped piece which is guided in the diagonal w of the main frame and
carries a spring which bears against the rear forked end of the arc-shaped
piece and is capable of being adjusted by means of two nuts y, y¹.
When the cycle is in use the hind fork is constantly pressed by the spring
rearwardly in the direction of the arrow, whilst the strain thus produced on the
chain can be regulated in a suitable manner by means of the nuts y, y'.
The action of the spring situated on the arc-shaped piece v may also be
replaced by the action of compressed air upon a piston as shown by Figures 4 and 5.
In Figure 4, a lever d' pivoted to the piston c' acts upon the pivotable hind
axle t', and the piston is actuated by the compressed air contained in the stay
tube sand which is introduced into the said tube through the valve e¹. In
Figure 5 the tubes is also closed at its forward end, and the rod f" which is fixed
to the piston c² and is supported in the front wall of the tube s², acts only through
the medium of the pivoted lever d² upon the axle t2 of the wheel. Both the
front and hind parts and st respectively of the tubes, are each provided with a
valve and respectively, of which the former k¹ opens outwardly, and the other
inwardly.
When the piston c² moves forward in consequence of the resistance of the hind
wheel running on the ground, then the compressed air contained in the front part så
of the tube becomes still further compressed until it raises the valve k¹ and escapes.
By this means the chain becomes tightened only after its slackness has allowed the
driving wheel to slip too far back, because it is only then that the compressed air
reaches the pressure necessary to lift the valve k¹. Air can be pumped afresh into
the rear chambers of the tube 2 through the second valve k², so as to produce a
pressure of the air therein which will counterbalance the pressure of the air
contained in the part 3 of the tube.
The advantage of these new devices as compared with all earlier ones hitherto
employed, lies mainly in the fact that the ratio of 'the gearing can be altered
easily, quickly and without much trouble, whilst the subsequent tension of the
chain is regulated automatically by means of the hind wheel fork which is operated
either by spring power or by compressed air.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is :-
(1.) A bicycle having an adjustable chain wheel for varying the ratio of the
gearing, and an automatic device operated by spring pressure or compressed air
for regulating the subsequent tension on the chain, substantially as hereinbefore
described and illustrated by the accompanying drawing.
(2.) In a cycle as specified in Claim 1, a device for automatically regulating
the tension of the driving chain, the arrangement being such that the hind
wheel fork o which is pivotel to the frame of the cycle is guided at one end
in are-shaped slots u in the bottom stays s; the said fork o being constantly
pressed outwards by a spring which is capable of adjustment by means of
Duts y, y, and is mounted on an arc-shaped piece v, the said spring bearing at
one end on the forked end v' of the arc-shaped piece v, and at its other end bearing
against the diagonal w, as set forth.
(3.) In a cycle as specified in Claim 1, a device for automatically regulating the
tension of the driving chain, the arrangement being such that the hind axle t' is
guided in an arc-shaped slot u¹ and is adjusted therein by means of a rod d'
pivoted to a piston c¹ acted on by compressed air contained in the stay tubes s¹, as
set forth.
(1.) A modification of the device specified in Claim 3 in which the rod
which

page_text: effects the adjustment of the hind wheel axle t2 is connected to a piston c² fixed on
a second rod /'; the air tube s being closed at both ends, whilst the front air
chamber & divided off by the piston c is provided with an outwardly opening
valve k', and the rear end chambers is provided with an inwardly opening valve k³,
as and for the purpose set forth.
(5.) An expansible and contractible chain wheel consisting essentially of
segments a, a, a³, a³, a, a³, mounted in the body of the wheel, of a star-piece g
rotatably mounted on the axle fand adapted to act on the segments a, a, a², etc.,
the said segments being guided by means of parallel slots c and pins b of the elastic
rim m having teeth n of the scale k on one of the toothed segments and of the
pointer on the star-piece g, all combined, arranged and adapted to operate as and
for the purpose set forth.
(6.) In an adjustable chain wheel as specified in Claim 5 a toothed rim composed
of a narrow steel band or strip m, the teeth n of which are formed by suitably
bending the said band or strip so that the entire toothed rim forms a highly elastic
or springy ring, as and for the purpose set forth.
Dated this 4th dow of Dabaho 1005
ROBERT E. PHILLIPS, Assoc. M. Inst. C.E., M.I. Mech. E.,
Consulting Engineer and Patent Agent,
70, Chancery Lane, London, W.C., Associate Agent.