Improvements in or connected with Crank Mechanism for Driving Velocipedes.
Year: 1895

page_text: Date of Application, 6th Dec., 1895
Complete Specification Left, 4th June, 1896-Accepted, 25th July, 1896
PROVISIONAL SPECIFICATION.
Improvements in or connected with Crank Mechanism for Driving
Velocipedes.
We, ERNEST SAMUEL SPENCER of 41 Gracechurch Street, Manager to a Public
Company and JOHN LEWIS WILES of 45 Finsbury Pavement Engineer, both in the
City of London, do hereby declare the nature of this invention to be as follows :-
:-
The invention relates to that class of crank mechanism in which an extended
leverage is obtained on the down stroke.
Heretofore an eccentric extending around the crank axis has been fixed to the fork
or frame of the machine and the pedal instead of being mounted at the end of the
crank as usual was in such case mounted at the junction of the eccentric rod with one
end of a link whose other end is pin-jointed to the outer end of the crank and so
arranged that the pedal is above the crank on the down stroke.
Our invention
consists of a novel arrangement and combination of parts whereby we obtain an
improved result and whereby if desired the increased length of crank may be
temporarily obtained on the up stroke to facilitate the descent of hills.
In carrying our invention into effect we also use a fixed eccentric, an eccentric strap
and rod, a crank and a connecting link, this latter being pin-jointed to the ends of the
eccentric rod and crank, but instead of mounting the pedal at the junction of the
eccentric strap and connecting link as heretofore we extend one end of the said
connecting link beyond its junction with the end of the crank and mount the pedal at
the free or extended end of such connecting link or lever so that on the down stroke
the pedal will be below the outer end of the crank. We also mount the eccentric
to the rear of the crank axle. If desired the outer end of the eccentric rod may
be provided with a slot to facilitate adjustment of the connecting link therein to
extend or reduce the length of stroke and in order to give greater control over the
machine in descending hills the eccentric instead of being a permanent fixture may
be provided with means whereby it may be thrown over from one side to the other of
the crank and held there as long as may be required so that in descending hills the
extended length of crank may be used for the up stroke.
Dated December 6th 1895.
HARRIS & MILLS,
23 Southampton Buildings, London, W.C., Agents.
HARRIS & MILLS,
23 Southampton Buildings, London, W.C., Agents.
Improvements in or connected with Crank Mechanism for Driving
Velocipedes.
We, ERNEST SAMUEL SPENCER, of 41 Gracechurch Street, Manager to a Public
Company, and JOHN LEWIS WILES, of 45 Finsbury Pavement, Engineer, both in the
City of London, 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 invention relates to that class of crank mechanism in which an extended
leverage is obtained on the down stroke.

page_text: ng around the crank axis has been nxed to the fork or frame of the machine,
and the pedal, instead of being mounted at the end of the crank as usual, was in such
case mounted at the junction of the eccentric rod with one end of a link, whose other
end is pin-jointed to the outer end of the crank, and so arranged that the pedal is
above the crank on the down stroke.
Our invention consists of a novel arrangement and combination of parts whereby
we obtain an improved result and whereby, if desired, the increased length of crank
may be temporarily obtained on the up stroke to facilitate the descent of hills.
Our invention is illustrated in the accompanying drawings, in which :-
-
Fig. 1 is a side elevation of a safety bicycle fitted with our improved crank
'mechanism.
Fig. 2 is a plan of parts thereof.
Fig. 3 is a side elevation of the crank mechanism drawn to a larger scale.
Fig. 4 is a plan of the same.
Fig. 5 is a side elevation and Fig. 6 is an edge elevation partly in section of one of
-the eccentric straps and rods.
Fig. 7 is a side elevation and Fig. 8 is a cross section of the eccentrics.
Fig. 9 is a side elevation of parts of the frame with one of the fixtures on which
the eccentrics are mounted.
Fig. 10 is an elevation of the same drawn at right angles to Fig. 9.
Fig. 11 is a side elevation of the crank mechanism showing the eccentrics thrown
over on the opposite side of the crank axle to that shown by the other figures, and
the increased length of crank thereby obtained on the up stroke.
In carrying our invention into effect we also use, as heretofore, in connection with
each crank mechanism, a fixed eccentric a, an eccentric strap a² and rod a², a crank b
fixed on the axis c, and a connecting link d, this latter being pin-jointed to the ends
of the eccentric rod a² and crank b, but instead of mounting the pedal at the
junction of the eccentric strap rod a² and connecting link d as heretofore, we
extend one end of the said connecting link d beyond its junction with the end of
the crank band mount the pedal e at the free and extended end of such connecting
link or lever d, so that on the down stroke the pedal e will be below the outer
.end of the crank b, as shown at Figs. 1 and 3. We also, in order to reduce
friction, form the eccentrics and eccentric straps with corresponding grooves to
receive bearing balls. The eccentric rod a², on the side of the chain wheel, is led
outward between spokes of the latter.
We also mount the eccentrics normally to the rear of the crank axle c and, if
desired, they may be a permanent fixture by being fixed directly to the bottom
bracket f, but we prefer, in order to give greater control over the machine in
descending hills, to provide means whereby the eccentrics may be thrown over
from one side to the other of the crank shaft and held there as long as may be
required, so that in descending hills the extended length of crank may be used
for the up stroke.
For this purpose we mount the eccentrics on guide pins g¹ carried by a bracket
fixed rigidly to the bottom bracket f, said eccentrics a being formed with guide
slots a³ to slide on the pins g' and with a central slot a to pass freely over the
crank axle c, and in order to enable the rider to readily shift the same from his
seat on the saddle, we provide a lever h mounted on a pin carried by a
bracket fixed to the head of the machine; the lower end of this lever is pin-
jointed to one end of a link j, whose other end is pin-jointed to the upper end
of a lever k; this lever is mounted on a pin carried by a bracket fixed to
one of the tubes forming the framing of the machine, and its lower end is pin-
jointed to one end of a link m, whose other end is connected to a cross bar n
connecting together the two eccentrics a. Thus, by moving the lever h either
forward or backward, the eccentrics a are moved from one side to the other of
the crank axle, or, if desired, the eccentrics a can be placed in a concentric
position with such axle by placing the lever h in its central position. The lever h

page_text: may be retained in the desired position by means of a pin or projection thereon
passing into one or other of the holes or recesses in the fixed quadrant o or by
other suitable means.
In Figs. 1 to 4 the eccentrics a are shown in their normal position, that is to
say, extending to the rear of the crank axle c, thereby obtaining the extended
length of stroke of the cranks on the down stroke as indicated by the full lines
in Fig. 3, whilst in Fig. 11 the eccentrics a are shown forward of the crank
axle c, whereby the extended length of stroke is obtained on the up stroke as
indicated by the broken lines in such figure, thereby giving the rider greater
control over the machine when descending hills.
If desired the outer end of each eccentric rod a² may be provided with a slot
as shown by broken lines a** on Fig. 3 to facilitate adjustment of the connecting
link d therein to extend or reduce the length of stroke, or a like effect can be
produced by means of a slot either in the end of the crank 6 or in the connecting
link d.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1. In crank mechanism for driving velocipedes, the combination with an eccentric,.
eccentric strap and rod, and crank, of a link or lever pin-jointed to the ends of said
eccentric rod and crank and extending beyond its connection with the crank, and a
pedal carried at the free end of said link, substantially as herein shown and described.
2. The combination of an eccentric, an eccentric strap and rod, a crank on the
crank axle, and a link or lover pin-jointed to the ends of said rod and crank and
extending beyond said crank and having a pedal at its free end, substantially as
herein shown and described.
3. The combination with crank mechanism for driving velocipedes, of adjustable
eccentrics mounted on brackets on the bottom bracket and adapted to be temporarily
fixed or held either forward or to the rear of the crank axle, or centrally thereof,
substantially as herein shown and described.
4. The combination of a pair of eccentrics, eccentric straps and rods, links or levers
pin-jointed to the ends of the eccentric rods and cranks and extending beyond the
latter, a pedal at the free or extended end of each link or lever, guides on which the
eccentrics are mounted, and connections from said eccentrics to a lever handle by
which they may be moved forward or to the rear of the crank axle, substantially as
herein shown and described and for the purpose stated.
5. In crank mechanism for driving velocipedes provided with an adjustable eccentric
mounted on a bracket on the bearing of the crank axle, means for temporarily
adjusting the eccentrics in any desired position relatively with the crank axle of the
machine as and for the purpose stated.
6. The combination with velocipedes of crank mechanism substantially as herein-
before described and illustrated.
Dated this 4th day of Inna 1806
HARRIS & MILLS,
23 Southampton Buildings, London, W.C., Agents.