Improved Driving Mechanism, specially applicable for Velocipedes.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improved Driving Mechanism, specially applicable for Velocipedes.
I, ARTHUR GURTEEN SMART, of Chauntry House, Haverhill, County of Suffolk,
do hereby declare the nature of this invention to be as follows:-
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The object of my invention is certain improvements connected with crank
mechanism specially applicable for the driving gear of velocipedes so that increased
leverage on the pedals down thrust is obtained by causing the crank to travel
eccentrically to the axle of the chain wheel or gear of say a bicycle.
For the purpose of my invention as applied to a rear driving bicycle, I connect
to or form the crank with a strap running on an eccentric, secured upon a fixed
axle carrying the chain wheel or other gear.
The crank has a fork or slot for engaging a pin fixed on the sprocket wheel
at or near its periphery so that motion is imparted to the wheel by the crank in
its rotation through its connection with the pin.
The longest throw of the eccentric and crank is about half distance on the
down thrust of the crank, and the shortest at a point directly opposite on the
ascending side, so that great leverage power is available during the working
portion of the pedal action.
The sprocket wheel may carry two guide pins, one on each side of the crank,
in which case the crank would be plain, the slot or fork being dispensed with.
1
.. 1007
H. GARDNER,
Patent Agent, 166, Fleet Street, London,
Agent for the said:.
-
Arthur Gurteen Smart.
Improved Driving Mechanism, specially applicable for Velocipedes.
I, ARTHUR GURTEEN SMART, of Chauntry House, Haverhill, County of Suffolk,
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:-
The object of my invention is certain improvements connected with crank
mechanism specially applicable for the driving gear of velocipedes so that
increased leverage on the pedals down thrust is obtained by causing the crank
to travel eccentrically to the axle of the chain wheel or gear of say, a bicycle.
For the purpose of my invention as applied to a rear driving bicycle I connect
the pedal crank to a strap running on an eccentric fixed to the pedal axle bracket
and around the axle carrying the chain sprocket wheel or other gear.

page_text: The crank has a fork or slot for engaging a pin fixed on the sprocket wheel at
or near its periphery so that motion is imparted to the wheel by the crank in its
rotation through its connection with the pin.
The longest throw of the eccentric and crank is about half distance on the down
thrust of the crank and the shortest at a point directly opposite on the ascending
side so that great leverage power is available during the working portion of the
pedal action.
The sprocket wheel may carry two guide pins one on each side of the crank in
which case the crank would be plain, the slot or fork being dispensed with.
My invention is shown on the annexed drawings.
Figures 1 and 2 are side elevations indicating the two extreme positions of the
pedal crank of say a bicycle. Figure 1 showing the thrust for the down or for-
ward stroke and Figure 2 the rear uprising portion of the stroke.
Figure 3 illustrates the two positions in a plan.
In these views A is the sprocket wheel B the strap. B₁ the eccentric C the
pin, on one side of the frame.
This strap B is affixed to the pin C passing through the lever D which is slotted
at two parts of its length at E F one to ride loosely upon the axle G and the other
to ride upon the pin H projecting from the side of the sprocket wheel A but slide-
able therein as the sprocket wheel A is rotated under the action of the pedal I
and its lever D, through its connection with the pin C.
The sprocket wheel A is as usual on one side of the machine and to enable the
repeat of the appliances to be fitted I mount upon the axle G next the
eccentric B a lever K to be carried round by the pin C, the pedal lever D¹
riding upon the pin H¹ and axle G as explained for the pin H on the other side
of the machine.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed declare that what I
claim is:-
1. The improved arrangement of driving mechanism for velocipedes as described
and shown by which increased leverage in the thrust stroke is obtained, said
increase being gradually obtained to a maximum and then gradually retiring as
and in the manner shown.
2. Fitting a stud pin H near the periphery of a sprocket wheel A of a velocipede
for carrying by pedal action said sprocket wheel round, the pedal lever D having
a sliding motion on said pin H and on axle G due to the varying positions of the
pin C of the eccentric B as and for the purposes specified.
Doted this 15th day of Not
1007
H. GARDNER,
Patent Agent, 166, Fleet Street, London,
Agent for the said A. G. Smart.