A Jointed Crank of Varying Length for Driving Cycles, and for other similar purposes.
Year: 1894

page_text: Date of Application, 20th Oct.,, 1894
Complete Specification Left, 19th July, 1895-Accepted, 24th Aug., 1895
PROVISIONAL SPECIFICATION.
A Jointed Crank of Varying Length for Driving Cycles, and for
other similar purposes.
I, ADOLPHE PHUNIER of 21 Boulevard Poissonnière, Paris, Mechanic, do
hereby declare the nature of this invention to be as follows:-
This invention consists in a jointed crank of adjustable length specially applicable
to driving cycles but also adaptable to analogous purposes.
Although this improved crank is jointed and of. varying length yet it can be made
with the aid of an accessory piece which may be either an eccentric a toothed
rack or any similar gear to describe a circular path practically if not actually
equivalent to that of an ordinary crank with fixed stroke; it increases the power
applied upon it in exact proportion to its extension which is automatically brought
about during the effective part of the stroke, and it automatically contracts during
the non-effective part of its revolution i.e. on the' up stroke when pressure' is
removed.
In carrying out my invention I take an ordinary driving axle fitted in the bracket
of the frame of a cycle with' the usual ball bearings, to which are keyed two
adjustable cranks of precisely similar' form and arranged diametrically opposite to
each other as in the 'case of ordinary cranks. Each of these cranks.consists of an
arm fixed on the axle the other end being forked to carry two pivots, in each of
which an equal jointed part is connected and the other extremities of these two
jointed parts are also pivotted to two other equal parts which at their further
extremities are together with the treadle joined to a common axis.
The two joints which are immediately connected with the fork of the crank arm
carry a toothed sector each, for the purpose of regulating the relative positions of
the jointed arms with reference to the fixed crank arm.
To the treadle is attached an arm connecting it with the axle of the wheel.
The inner portion of this arm is made in the form of an oblong link and is
farnished on each longer side with a rack arranged to 'engage alternately. with a
ball-bearing pinion fixed upon the axle and provided with teeth for a sufficient
portion only of its circumference as to ensure its engaging alternately with the two
racks on the inner end of the arm and which pinion is prevented from revolving:by
means of a bar rigidly attached to the frame of the machine:
The action of the parts as follows:-
Pressure exerted on the treadle in the usual manner brings into gear one rack of
the oblong link with the fixed pinion already described and causes the link to travel
across the axis of the wheel until the link arrives at the end of its stroke whereupon
the opposite rack is brought into engagement with the pinion and the travelling
direction of the link is reversed. At the commencement of the stroke the crank is
extended to it's greatest length' and gradually contracts until a position directly
opposite its starting point is reached when it will be at its shortest length; at which
position the teeth of the pinion will be thrown out of gear with cne rack and into
gear with the other. From this point the crank gradually and automatically
extends until the original position is reached. This coincides with the moment
when the pressure necessarily exerted is at its maximum:
In operation it will be found that the path 'described by the treadle will be a
complete circle with its centre eccentric to the axle of the fixed crank arm.
The nation of the second exaulis similar.

page_text: Keyed or otherwise secured upon the axle is the ordinary chain wheel which
transmits motion by means of a suitable chain from the axle to the pinion of the
driving wheel.
I may apply the adjustable jointed crank not only to cycles, but also to other
analogous purposes.
4
I do not confine myself to the particular construction and number of working
parts above specified, but to the general arrangement, described, and I may use for
the purposes of construction metal or any suitable materials.
Dated this Twentieth day of October 1894.
A Jointed Crank of Varying Length for Driving Cycles, and for
other similar purposes.
I, ADOLPHE PRUNIER of 21 Boulevard Poissonnière, Paris, Mechanic, 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 consists in a jointed crank of adjustable length specially applicable
to driving cycles but also adaptable to other analogous purposes.
Although this improved crank is jointed and of varying length, yet it can be
made with the aid of an accessory piece,-which may be either an eccentric a toothed
rack or any similar gear-to describe a circular path, practically if not actually
equivalent to that of an ordinary crank with fixed stroke; it increases the power
applied upon it in exact proportion to its extension which is automatically brought
about during the effective part of the stroke, and it automatically contracts during
the non-effective part of its revolution, i.e. on the upstroke when pressure is
removed.
I attain this object by the arrangement of mechanism illustrated on the
accompanying drawings on which
Figure 1 is a front elevation of my improved jointed crank as applied to the
pedal axis of a bicycle.
Figure 2 being a horizontal section of the same on line 1-2, sbewing one crank B
in section, and the other B' in plan.
--
In carrying out my invention I adopt the following method of construction :-
Upon an ordinary pedal axle A, having bearings in a socket a formed in the
frame of a cycle, are secured two jointed cranks B B', of adjustable length, simi-
larly constructed, and arranged at the ends of the axle A in diametrically opposite
positions. Each of the jointed cranks B B' consists of a fixed arm directly
secured upon the axle A, and four jointed parts or arms 1, 6, 63, 64, two of which,
viz. 6 and 6, are separately pivoted upon the fixed arm b, whose extremity is forked
for the purpose of receiving two independent pivots. The other two arms-
band are pivoted respectively to the outer ends of arms and 63, and are
brought together at their further extremitics at a common point 5 where they are
pivotally attached to a lever C, one part of which passes around the axle A and is
of special construction as described below. That portion of the lever C which is
nearer to the centre or axle A is formed into an oblong link, D, with semi-circular
ends carrying upou and within its longitudinal sides toothed racks C1, C2 arranged
to engage alternately with a stationary pinion F fixed around the axle A, and
provided with teeth only on a sufficient portion of its circumference to ensure that
effect. This stationary pinion F is provided with ball-bearings, and is prevented
:

page_text: from independent rotation by means of a suitable retaining bar G, arranged for
that purpose upon a convenient part of the frame of the machine.
the bush d in position.
A nut e secures
All the joints 1, 2, 3, 4 and 5 of the pivoted arms of the crank are similarly
furnished with friction bearings consisting of a bush d having two flanges_d', dª
screwed together and enclosing two rows of balls c c', revolving in grooves formed
in the bosses of the several arms.
Upon the central boss of the fixed crank arm is mounted a collar f, arranged so.
that its circumference affords a bearing alternately to one or other of the
semi-circular euds of the oblong link D of the lever C.
In order to regulate the relative movements of the arms b¹, 62, 63, 64 in working,
toothed sectors s, s1, arranged to engage together, are provided upon the inner
adjacent ends of the arms b¹ and respectively.
A pedal is pivoted on the lever C at the point 5, where the arms b* and * are
pivotally connected as previously described.
In working, the action of the parts is as follows:-Pressure being exerted upon
the pedal at 5, in the direction indicated by the arrow X, brings the lever C into
such a position that the toothed rack C¹ comes into gear with the teeth of the
stationary pinion F, whereby the oblong link is caused to travel across the axis A
until it arrives at the end of its stroke. At this moment the semi-circular end of
the link nearer to the outer part of lever C is brought into contact with the
periphery of the collar, which affords it a bearing until by the revolution of
lever C, the other rack, C, is brought into engagement with pinion F, whereupon
the oblong link is caused to return across the axis A, until its inner end comes
against the collar f.
It will be seen that the jointed crank B at the commencement of the stroke, as
shewn on Figure 1, is extended to its maximum limit, and with the forward
movement of the pedal it then gradually contracts until it reaches a position
directly opposite the starting point when it will attain its minimum length, simul-
taneously with the pinion F being thrown out of gear with one, and into gear with
the other of the toothed racks C'C'. This portion of the stroke takes place
whilst pressure is removed from the pedal. From this point in its revolution the
crank will gradually and automatically extend until the original position or assumed
starting point is reached, and this will coincide with the moment when the pressure
necessarily exerted in driving is at its maximum.
To transmit motion from the crank axle to the rear wheel in the case of rear-
driving machines, a chain wheel H may be mounted upon the axle A, see Figure 2,
and the ordinary chain connection provided with the pinion of the rear axle.
The action of the second crank B' is similar to that above described. It will be
found that in operation the pedal will describe a circle with its centre eccentric to
the axle of the fixed crank arm b.
In lieu of the toothed rack and pinion for effecting the automatic extension and
contraction of the jointed crank as described, I may otherwise utilize an accessory
piece consisting either of an eccentric or equivalent gear.
I may apply my adjustable jointed crank not exclusively to the driving mechanism
of cycles, but likewise to other analogous purposes; and I do not confine myself to
the particular construction and number of working parts above specified, but to the
general arrangement described, and I may use metal or other suitable materials for
the purposes of construction.
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 in a jointed crank of a reciprocating lever C furnished with
racks C C and arranged to be operated by means of a stationary pinion F, with
the jointed arms b₁, 6, 6, and toothed sectors s, & substantially as shewn and
for the purposes specified.

page_text: 2. In jointed cranks having arms b',.6, 6, 64,,the joints 1,,2, 3, 4 and 5, comprising
a bush:d having flanges d', din combination with the balls,c, c' revolving in grooves,
as and for the purposes described.
3. In jointed cranks the toothed' sectors s, s¹ on arms: 6 substantially as shewn
and described.
4. In jointed crauks an oblong link D. furnished with racks C¹, C and having
semi-circular ends arranged to bear alternately upon a revolving collar fas and for
the purposes specified.
5. In jointed oranks a pinion F and retaining bar G for the purpose of securing
the same immovably in position substantially as herein described with reference to
the accompanying drawings.
6. Jointed cranks: constructed combined and arranged substantially as described
and illustrated upon the accompanying drawings.
Dated this Nineteenth day of July 1895