Improvements in Mechanism for Transmitting Power, applicable to Rear Driven Safety Bicycles.
Year: 1892

page_text: Date of Application, 3rd Feb., 1892
Complete Specification Left, 10th Oct., 1892-Accepted, 3rd Feb., 1893
PROVISIONAL SPECIFICATION.
Improvements in Mechanism for Transmitting Power, applicable to
Rear Driven Safety Bicycles.
JOHN WARDEN BAIRD 9 Union Street, Edinburgh Engineer do hereby declare
the nature of this invention to be as follows:-
This invention relates to driving rear driven safety bicycles by means of gearing,
and dispensing with the usual manner of driving them by an endless chain. To
effect this end, I use the sun & planet gearing or other suitable gearing attached
to the driving wheel of the bicycle. The driving wheel is mounted on a tube axle
and passing through this tube axle is an inner axle, and keyed to each end of it are
cranks set at an angle to each other preferably set at right angles or other suitable
angle. Corresponding cranks set at the same angle as the cranks on the driving
wheel axle are attached to the ends of the pedal crank axle.
The crank pins, the pins where the connecting rods are attached (as the cranks
have also other pins where the pedals are attached) are made with an attachment
cast or otherwise fixed to them, or in one casting, or forging, so that the cranks are
lengthened from their connecting rod pins say three inches more or less in the
direction of the pedals, that is to say the cranks would have a throw of about six
inches from centre of crank spindle to centre of pedal spindle. The cranks on the
driving wheel and the cranks on the pedal axle are attached on either side of the
bicycle by means of connecting rods, the throw of these cranks would be about
three inches. The other crank is lengthened from its connecting rod crank pin in
the same way as its neighbour, only the part lengthened takes the form more or less
of a bell crank, so that the connecting rod cranks are at right angles or other
suitable angle, whereby they cannot be prevented from revolving by being jamed
on their dead centres.
The pedals are owing to the use of the bell crank opposite each other in the
usual position. By this means the circular motion of the pedals is still retained, as
in a chain driven bicycle; and as the gear wheels can be enclosed in a case all grit
and dirt is excluded from them.
COMPLETE
SPECIFICATION.
Improvements in Mechanism for Transmitting Power, applicable to
Rear Driven Safety Bicycles.
JOHN WARDEN BAIRD Engineer 9 Union Street Edinburgh 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 driving rear driven safety bicycles by means of gearing
and a suitable arrangement of cranks & connecting rods & dispensing with the
usual manner of driving them by means of an endless chain. To effect this end I
use a geared up hub such as is used in a geared up ordinary bicycle, or other suitable
gearing attached to the driving wheel of the rear driven bicycle.
The pedal axle cranks instead of being straight as is usually the case are diverted
from the straight line by a crank pin fitted to each crank & attached thereto by a
cotter pin or other suitable means.
The double driving pedal crank with its crank pin may also be cast or forged in
one piece. The connecting rod crank pins are about equidistant or other suitable

page_text: distance between the centre of the pedal crank axle & the centre of the pedal
crank pins. The cranks being extended more or less from these mid crank pins in
the direction of the pedals, so that a driving crank of the usual throw is obtained.
The pedal cranks that have these connecting rod crank pins are set at right angles
to each other or other suitable angle. The connecting rods that transmit the
driving power to the driving wheel are coupled to these crank pins ; & the opposite
ends of these connecting rods being coupled to crank pins on cranks set at a similar
angle and of the same throw attached to the driving wheel axle on its opposite ends.
In order that the pedals may be directly opposite each other, one or other of the
pedal cranks is curved, bellcranked, or made straight & set at a suitable angle.
The other pedal crank is straight or in line with its connecting rod crank. Pre-
ferably the pedals are opposite each other; but both pedal driving cranks may be
curved or set at a suitable angle, so that the pedals would then not be quite opposite
each other. The connecting rod cranks being at right angles cannot become jamed
on their dead centres, either in forward or back pedaling, as when one crank pin is
on its dead centre the other crank pin is pulling it off.
There being a connecting rod on each side of the bicycle the power is transmitted
to the driving wheel very equally. The geared up driving hub, or other gearing
being incased is thereby kept free from dust, & the chain with its adjustments & mud
collecting propensities is entirely dispensed with.
DESCRIPTION OF DRAWINGS.
Figure 2 shown in elevation.
Figure 1 shown in plan.
A driving hub fitted as a geared up hub, or with other suitable multiplying
gear, B. B driving wheel. C. C. frame of bicycle. D. D. connecting rods for
transmitting power from pedal cranks to driving wheel. E pedal crank bracket.
F. F. F. F. connecting rod driving cranks. G. G. G. G. connecting rod crank pins.
H. H. pedal driving cranks extended from connecting rod crank pins G. G.
Having now described the nature of my said invention and in what manner the
same is to be performed, I declare that what I claim is :-
1st. Adapting double driving pedal cranks to rear driven safety bicycles, where
each crank is fitted with a crank pin independent of its pedal crank pin, whereby
power is transmitted to the driving wheel by these crank pins, as described.
2nd. One or other of the pedal cranks from its connecting rod crank pin is curved,
bell cranked, or can be straight and set at a suitable angle, so that the pedals are
directly opposite each other; or both the double driving pedal cranks can be set at
an obtuse angle to each other, or other suitable angle.
3rd. The improvements in rear driven safety bicycles substantially as described
and illustrated in the annexed drawings.
Dated this 3rd day of October 1892
JOHN WARDEN BAIRD,
9, Union Street, Edinburgh, Engineer.