Improvements in Driving Mechanism for Velocipedes and other Foot Driving Machines.
Year: 1893

page_text: Date of Application, 4th Apr., 1903
Complete Specification Left, 2nd Jan., 1894-Accepted, 3rd Feb., 1894
Complete Specification Left, 2nd Jan., 1894-Accepted, 3rd Feb., 1894
PROVISIONAL SPECIFICATION.
Improvements in Driving Mechanism for Velocipedes and other
Foot Driving Machines.
JOSEPH BUCHANAN ROBERTSON of 184 Grosvenor Street, Belfast, Engineer
and JOHN BIRRELL ROBERTSON of 40 Turin Street, Belfast, in the County of
Antrim Ireland Engineer, do hereby declare the nature of this invention to be
as follows:
Our invention consists in arranging the levers or cranks and pedals of velocipedes
or other foot power machines, so that when one crank has reached the point where
its propelling power is exhausted the other crank will have passed into a position
to make its propelling power effective. This is accomplished by placing the levers
or cranks on centres slightly eccentric to and independent of the main driving axis
of a velocipede or other machine as at present constructed, the levers or cranks
being connected to the driving axis. Such connection may either be by links or by
studs working into slots or other device.
Dated this 31st day of March 1803
JOSEPH BUCHANAN ROBERTSON.
JOHN BIRRELL ROBERTSON.
COMPLETE SPECIFICATION.
Improvements in Driving Mechanism for Velocipedes and other
Foot Driving Machines.
We, MARY WILSON ROBERTSON (Executrix of the late Joseph Buchanan
Robertson) and JOHN BIRRELL ROBERTSON, both of 184 Grosvenor Street,
Belfast Ireland, 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:
Our invention consists in arranging the levers and cranks and pedals of velocipedes
or other foot power machines so that when the one crank reaches the point where
the foot can no longer effect propulsion, the other crank is in such a position that
the foot is effective in propelling.. For this purpose we construct the driving
mechanism as we shall describe referring to the accompanying drawings.
Fig. 1 is a front view. Fig. 2 is a longitudinal section and Fig. 3 is a diagram
shewing the pedal levers in various positions during their revolution.
A is the pedal axle, to one end of which one of the pedal levers B is fixed, the
other end of A having fixed on it an arm C in line with B.
The other pedal lever D is formed with a sleeve E which can turn freely on the
axle A. The arm C is connected by a link F to a crank pin G on the sprocket
driving wheel II, and the lever D is connected by a link K to another crank pin L
on the driving wheel diametrically opposite to G. The wheel H is fitted to revolve
on a boss M the centre m of which is a little on the one side, that is to say, in front
of the centre a of the axle A. We have shewn ball bearings for the axle A and
the wheel H, but the arrangement of these might be varied, or other forms of
bearing might be employed. On examing Fig. 3 it will be seen that, owing to the
eccentricity of the centres of the axle A and the wheel H, each pedal lever
alternately moves through more than half a revolution in its upstroke and less than
half a revolution in its downstroke; thus in Fig. 3 D ascends to the position

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occupied by B during the time that B descends to the position of D.
consequence of this movement is that when the one pedal, such as D. is no longer
effective for driving the other B has already passed the upper dead centre and is
in position to be effective. Instead of connecting the pedal levers to the wheel by
links as shewn, the connection might be made by pins working in slotted holes.
Having now particularly described and ascertained the nature of our inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:
In a velocipede or other foot driven machine, mounting the two pedal levers on
an axis free to rotate independently, and connecting cranks driven by them by
links to opposite cranks on a driving wheel the axis of which is eccentric to the
axis of the pedals substantially as and for the purpose set forth.
Dated this 2nd day of January 1894.
ABEL & IMRAY,
Agents for the Applicants.