Improved Driving Mechanism for Safety Bicycles.
Year: 1896

page_text: This Print is in accordance with the Original Specification as it stands after
Amendment (under Section 18 of the Patents, &c., Act, 1883), as allowed
by the decision of the Comptroller General of the 30th day of July 1897.
Date of Application, 17th Mar., 1896-Accepted, 2nd May, 1896
We,
COMPLETE SPECIFICATION (AMENDED).
Improved Driving Mechanism for Safety Bicycles.
WILLIAM
LAVERUX NELSON DYHRBERG, Brickmaker, WALTER
CURTIES, Cycle Engineer, and ALBERT CRUM, Brick-yard Proprietor, all of
71 Cathedral Square, Christchurch, in the Provincial District of Canterbury, in
the Colony of New Zealand, 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 provides mechanism designed to have the following improvements
upon the chain gearing commonly employed upon safety bicycles.
The pedals are attached to levers and vibrate through an arc instead of describing
a complete revolution, whereby the "dead centres" usual when employing ordinary
driving cranks are avoided, the length of stroke can be varied and the pedal action
entirely suspended while the machine is in motion.
In practice we provide a pedal lever upon either side of the machine fulcrumed
upon a spindle carried in the bottom bracket or in bearings attached thereto. To
each pedal lever is connected a quadrant lever to which is secured one end of a
flexible cord or chain which is coiled round the drum of a clutch upon either side
of the driving wheel, the cord being led froin one side of the machine to the other
by means of a guide pulley.
The clutch drums are mounted upon the axle of the driving wheel and are free
to revolve in one direction, but when turned in the other, severally engage, through
the medium of an ordinary clutch arrangement with the teeth of ratchet wheels
fixed upon either side of the axle.
The pedal levers are connected by bevil gearing whereby the vibration of a lever
in one direction is communicated to the other in the opposite direction.
We will now more particularly describe our invention by the aid of the accom-
panying drawings wherein,-
Figure 1 is a side elevation of a bicycle fitted therewith.
Figure 2 is a side view, and,
Figure 3 a plan illustrating the driving mechanism.
Figure 4 is a sectional elevation illustrating the bevil wheels connecting the
pedal levers.
Figure 5 is a side elevation partly in section, and
Figure 6 is a central section shewing a convenient form of drum and clutch.
Figure 7 is a side view illustrating a modification wherein a separate driving
cord is employed upon either side of the machine.
Similar letters of reference indicate corresponding parts in all the figures.
The pedal levers (a) (b), to the outer ends of which are attached the
pedals (a) (b), are mounted upon spindles (a 2) (b2) carried in bearings in the bottom
bracket (c) of the machine. The quadrants (d) (e) which are connected to the

page_text: pedal levers (a) (b) respectively are preferably made with a U shaped channel to
receive the flexible chain or cord (f) which is fastened to the forward end of the
channel in the quadrant (d), is le fo and coiled around the clutch drum (g) and
passed over the guide pulley (h) conducting it to the other side of the machine
where it is coiled round the drun (k) and then carried to the quadrant (e) and
secured to the forward end of the channel with which it is provided. The guide
pulley () is mounted on a spindle secured to any convenient part of the frame,
preferably between the seat pillar and the driving wheel as shown.
In the clutch gear shewn in Figures 5 & 6 (which might be substituted by any
other couvenient form of clutch arrangement) a ratchet wheel (i) which is fixed to
the driving axle () of the machine is encircled by the drum (k) having flanges (4)
to keep the flexible cord from slipping off, and is carried upon the driving axle ()
by the discs (m) (n) which are screwed one into each side of the drum and provided
with bearings (o) (1).
Steel rollers (r) are placed one in each of the teeth of the ratchet wheel (2), and
upon the drum being revolved in the direction of the arrow (Fig. 5) these rollers
move outwardly and act as a wedge betwees them and the inner periphery of the
drum (E).
In operation when one of the pedal levers is depressed by the foot of the rider
the quadrant connected to it moves through a corresponding are thereby pulling
the flexible driving cord or chain and causing the clutch drum upon that side of the
machine to revolve and consequently to clutch the ratchet and turn the driving
wheel. The driving cord passing over the guide pulley (k) also pulls upon and
revolves the drum upon the opposite side of the machine whereby the pedal lever
upon that side is raised ready for a downward stroke of the foot of the rider.
It will be evident that the upward stroke of one pedal lever is coincident with
the downward stroke of the other, and that the length of stroke depends, within
certain limits, upon the will of the rider.
In the mechanism so far described it will be seen that if the machine is run
backwards both the pedal levers will he raised by the driving cond which will
become slack upon the guide pulley and liable to run off the drums. To obviate
this the gearing now to be described is employed, whereby the machine is prevented
from being moved back while it is also useful in a modification to be described
where it is required that movement in either direction of a pedal lever upon either
side shall be communicated to the other pedal lever in an opposite direction.
We effect this by the parts illustrated in Figure 4 wherein the pedal levers (a) (b)
are fixed upon spindles (2) (62) respectively revolving in bearings (3) (63)
carried on the bottom bracket (c). To the spindle (a 2) is fixed the hevil wheel (s)
which gears with an intermediate wheel (t) revolving upon the stem of the
T. piece (u) which is carried in recesses formed in the ends of the spindles (2) (2)
respectively. The bevil wheel (w) is fixed upon the spindle (62) and gears also
with the intermediate wheel (t). The wheel (t) is kept upon the stem of the
T piece (a) by a nut (y) which is senewed upon the end thereof, a hole being
provided in the bracket (c) through which the nut can pass. The cases of the
bearings (3) (63) are formed upon dises (4) (64) which are secured to each
side of the bottom bracket (c) by bolts (b5). It will be evident that an attempt.
to run the machine back will cause both the pedal levers to tend to rise at the same
time and result in their becoming locked through the bevil wheels, while when one
pedal lever is vibrated by the foot of the rider the movement is conveyed to the
other in an opposite direction. If desirable we substitute a complete wheel for
each of the quadrants () (e) and instead of employing a single driving cord carried
from one side of the machine to the other by a guide pulley, employ the modification
shown in Figure 7 wherein a separate driving cord is used upon each side of the
machine, the cord upon each side being wound around a clutch drum (g), and passed
around a wheel () which has a V shaped channel upon its periphery and takes
the place of the quadrant before described. The cord is secured at one point in the
channel so that the drum may be revolved in either direction without slackening

page_text: the cord. When this arrangement is used it is necessary to connect the pedal levers
by means of the bevil gear described and shown in reference to Figure 4 or to
use other gearing having the effect of raising one pedal lever when the other is
depressed and vice versa.
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. In driving mechanism for safety bicycles, the employment of a separate
flexible driving cord or chain upon each side of the machine, each cord being
passed round and arranged to revolve the drum of a clutch gear and running in a
groove formed in the periphery of a wheel to which it is secured and which acts as
a lever to pull or be pulled by the driving cord in either direction substantially as
and for the purposes described herein and illustrated in Figure 7 of the accom-
panying drawing.
2. In driving mechanism for safety bicycles, the arrangement of bevil wheels
whereby the vibration of the pedal lever upon one side of the machine is communi-
cated to the pedal lever upon the other side in the opposite direction, substantially
as and for the purposes described herein and illustrated in Figure 4 of the accom-
panying drawing.
3. In combination the pedal levers (a) (b), the bevel wheels (8) (w) connected by
the intermediate wheel () as and for the purposes herein described and illustrated
in the accompanying drawings.