Improvements in and relating to the Frames and Driving Gear of Rear-driven Safety Bicycles.
Year: 1893

page_text: PROVISIONAL SPECIFICATION.
Improvements in and relating to the Frames and Driving Gear of
Rear-driven Safety Bicycles.
JOHN WARDEN BAIRD Engineer Pilmore Pencaitland East Lothian N.B. do
hereby declare the nature of this invention to be as follows:-
This invention is designed to drive rear driven safety bicycles by means of a
suitable arrangement of cranks and connecting rods working along with gearing,
and to dispense with the usual method of driving by means of an endless chain, and
is performed as follows. The pedal crank axle is forged or cast with two driving
cranks formed upon it, these cranks are placed at right angles to each other, or
other suitable angle, to the outside of these cranks are the pedal axle bearings,
(plain or ball) and beyond these bearings are the pedal cranks which are made of
the usual form. Coupled to pins on each of the driving cranks on the crank axle,
is a connecting rod, these rods transmit the power to pins attached to cranks which
are fixed at each end of the driving wheel axle These cranks are set at the same
angle as the cranks on the pedal crank axle which the connecting rods are coupled
to. At one end of the driving wheel axle is fitted the sun and planet gearing, or
other suitable multiplying gear, so that the driving wheel which is built on a tube
axle revolves at a greater speed than the driving axle which passes through it.
Both the tube axle of the driving wheel, and the driving axle which passes through
it, are mounted on independent sets of ball bearings. In order that the connecting
rods may be made to work within the framing of the bicycle, the framing is altered
from the usual design as follows. The back stays which extend from the pedal
axle bearings, and the stays which extend from the saddle pin bracket instead of
being attached direct to the driving wheel axle, are attached, along with the driving
wheel bearings to both sides of the machine to frames of a longitudinal or other
suitable form. These frames are of such dimensions that they admit of the driving
cranks, and the connecting rod ends, along with the gear wheels revolving freely
within them. In order that the frames referred to may be as rigid as possible they
are made continuous, or they may be made of greater strength and in that case
would not require to be made continuous. Preferably these longitudinal frames
are placed in line with the back stays that extend from the saddle L pin bracket,
but they may be placed in any other suitable position. By this arrangement of
framing the connecting rods are kept quite out of the way, and being within the
framing are not likely to be damaged. The chain with its adjustments, dirt, and
friction is dispensed with, and a driving gear substituted which is practically free
from these objections. The driving cranks which are at right angles to each other,
and are connected by the connecting rods are in this way prevented from jaming
on their dead centres.
Dated Fourth day of December 1893.

page_text: Improvements in and relating to the Frames and Driving Gear of
; Rear-driven Safety Bicycles.
.
I, JOHN WARDEN BAIRD, of Pilmore, Pencaitland, East Lothian, N.B.,
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 which is illustrated in side elevation by Figure 1, in plan by
Figure 2 and in vertical sections on the lines x- and y-y at Figures 3 and 4
respectively of the accompanying drawings, is designed to drive rear driven safety
bicycles by means of a suitable arrangement of cranks and connecting rods together
with gearing and to dispense with the usual manner of driving with an endless
chain. For this purpose the pedal crank axle A which has its bearings in the
pedal crank bracket B on the frame of the machine is forged or cast with two
driving cranks A' upon it, these cranks being set at right angles or other suitable
angles to each other. At opposite ends of the pedal crank axle are fixed the pedal
cranks B which are made of the usual form, and are placed diametrically opposite
each other. A connecting rod C is coupled to each of the crank pins of the cranks A¹
formed on the pedal crank axle A. These connecting. rods C transmit the power
to crank pins attached to cranks D fixed to the outer ends of the rear driving
wheel axle E which has its bearings in a bracket B2 said cranks being set at the
same angle as the cranks on the pedal crank axle A with which the connecting rods
are coupled. At one end of the driving wheel axle E is fitted the sun and planet
gearing F, G, or any other suitable multiplying gear may be used so that the
driving wheel which is built on a tubular hub H revolves at a greater speed than
the driving axle which passes through it.. Both the tubular hub H of the driving
wheel and the driving axle E which passes through it are mounted on independent
sets of ball bearings. In order that the connecting rods C may be made to work
within the framing of the bicycle the framing is altered from the usual design as
follows; the back stays which extend from the pedal crank axle bearings and the
back stays which extend from the saddle pin bracket instead of being attached
to the axle of the driving wheel I by means of a bracket of the usual shape are
attached along with the driving wheel bearings at both sides of the machines to
frames J of an oblong or other suitable form. These frames are of such dimensions
that they admit of the driving cranks and the connecting rod ends along with the
gear wheels revolving within them thereby protecting the gearing and in order
that these frames may be as rigid as possible they are made continuous or in one
piece, but they may be made in separate parts fixed together by bolts or other
suitable means. Preferably these longitudinal frames are placed in line with the
back siays that extend from the saddle L pin bracket in the direction of the driving
wheel axle, but they may be placed in any other suitable position.
This arrangement reduces friction to a minimum, is cleanly when working, rarely
requires to be adjusted for wear and is durable and little affected by mud while in
motion.
The driving cranks being set at right angles or other suitable angles to each
other and coupled together by the connecting rods, are prevented from jamming on
their dead centres, as when either of the cranks is on its dead centre the other
crank is pulling it over that centre.
This gear can also be applied to tandem safety bicycles, and when so fitted,.the
framing is extended in the direction of the front rider aud another pedal cranked
axle is used, this axle is coupled to the rear pedal cranked axle by means of
connecting rods.

page_text: 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. The combination of parts constituting the improved frame and driving gear of
rear driven safety bicycles substantially as described with reference to the annexed
drawings.
2. In a safety bicycle the combination of the cranked pedal driving crank axle
and connecting rods with sun and planet gearing arranged to drive the rear wheel
substantially as described with reference to the annexed drawings.
Dated this 3rd day of September 1894.
J. W. BAIRD.