An Improved Mechanism or Linkwork for the Conversion of Reciprocating into Rotary Motion.
Year: 1896

page_text: Date of Application, 15th July, 1896
Complete Specification Left, 10th Apr., 1897-Accepted, 17th July, 1897
An Improved Mechanism or Linkwork for the Conversion of
Reciprocating into Rotary Motion.
A communication by FRIEDRICH AHRENS, of 4 Boas Strasse, Munich, in the Empire
of Germany, Mechanician.
I, GEORGE CECIL DYMOND, M.I.M.E., of the Firm of W. P. Thompson & Co., of
6, Lord Street Liverpool, and 6, Bank Street, Manchester, both in the County of
Lancaster, 118 New Street, Birmingham in the County of Warwick and 322 High
Holborn in the County of Middlesex, Patent Agent, do hereby declare the nature of
this invention to be as follows:-
This invention has for its object an improved mechanism or gearing for the
transference of power in which mechanism the alternate up and down movement of
two levers is converted into continuous rotary motion.
Two wheels are keyed on the axle which is to be set in continuous rotation, and
each of said wheels carries two studs or points of engagement with which arms pivoted
on two oscillating levers alternately engage. The levers are revolubly mounted on a
fixed axis or spindle, and power is conveyed by pressing down one lever, whilst the
other lever is being raised free by means of rack gearing with a curved rack mounted
on the levers for the following delivery of work. The levers are double elbow levers,
on the ends of which the pivoted arms are revolubly mounted. In order to constantly
maintain the pivoted arms in contact with the wheels, each two arms belonging to a
wheel are held together by means of a spring, and this is preferably arranged so as to
be adjustable in order to admit of being tightened up when required.
The wheels, and the pivoted arms form two parts standing at suitable distances.
Crescent shaped projections or cams are provided on one side, and have for their object
to prevent the pivoted arins when passing over the studs or points of engagement
from coming in contact with those points of engagement which they ought not to
engage.
The front ends of the pivoted arms are formed of two parts, having a connecting
piece between with a suitable slot with which they engage the studs or points of
engagement on the wheels. These slots are preferably provided with india rubber
buffers in order to obtain a quiet and steady movement.
The front ends of the two parts of the pivoted arm ends are formed in such a way
as to bring the seperate arms in and out of engagement with the proper studs each
time. The one part has also a curved projection or cam which is arranged over one
of the discs of the aforesaid wheels, so as to effect a lifting of the pivoted arms from
off the studs. The said projections or cams may be on one side, or on both sides and
be adjustable, so that by reversing, by means of an arm, the front or the rear cam
may serve for raising or lifting up the pivoted arm, so that it is possible to allow the
motor to run backwards.
The mode of action of the device is as follows:-
On the descent ef the one lever, the slot of the pivoted arin engages in a stud or
point of engagement of the one wheel and turns the same about 90°. The slot of the
second arm then engages with the second stud. The moment the second arm is

page_text: engaged with its stud, the first arm is lifted up by the cam. The second arm then
effects a further rotation of the wheel to the amount of 90° so that the shaft has been
turned 180°. In the meantime the other lever has been raised by the rack gearing
and the other arms come into engagement with the other studs. During the descent
of this lever a further rotation of 180° of the shaft is effected, in a similar manner,
and the first named arms are held out of engagement with the studs by means of the
cam and the crescent shaped projections. Simultaneously the first lever is again
raised for a fresh impulse.
The invention is applicable for the transference of power for mechanical, or foot
driving machinery and is particularly applicable to cycles.
Dated this 14th day of Tule 1906
An Improved Mechanism or Linkwork for the Conversion of
Reciprocating into Rotary Motion.
A communication by FRIEDRICH AHRENS, of 4 Boas Strasse, Munich, in the Empire of
Germany, Mechanician.
I, GEORGE CECIL. DYMOND M.I.M.E. of the Firm of W. P. Thompson & Co. of
6, Lord Street, Liverpool and 6, Bank Street, Manchester, both in the County of
Lancaster, 118, New street, Birmingham, in the County of Warwick, and 322, High
Holborn in the County of Middlesex, Patent Agent, 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 has for its object an improved mechanism or gearing for the
transference of power, in which mechanism the alternate up and down movement of
two levers is converted into continuous rotary motion.
The invention is shown in the accompanying drawings, in which
Figure 1 is a sectional side élevation;
Figure 2 a plan view;
Figure 3 is a side elevation of the wheel b;
Figure 4 a section through the driving axle of Fig. 1;
Figures 5-6 detail views of the ends of the arms;
Figure 7 a side elevation of the device applied to a bicycle; and
Figure 8 a plan view of the same; and
Figures 9 and 10 detail views.
Two wheels b and c are keyed on the axle a which is to be set in continuous
rotation, and each of said wheels carries two studs or points of engagement d' d' and d³ d'
with which arms fi f and f³ f* pivoted on two oscillating levers e' e alternately
engage. The levers el e² are revolubly mounted on a fixed axis or spindle g, and
power is conveyed by pressing down one lever, whilst the other lever is being raised free
by means of a pinion h gearing with a curved rack i 2 mounted on the levers for the
following delivery of work. The levers el e² are double elbow levers, on the ends of
which the pivoted arms f¹ to fare revolubly mounted. In order to constantly
maintain the pivoted arms f¹ to f' in contact with the wheels b and c, each two arms
belonging to a wheel are held together by means of a spring k, and this is preferably
arranged so as to be adjustable in order to admit of being tightened up when
required.
The front ends of the pivoted arms ffff are formed of two parts m n, Figures 5,6
and 6, having a connecting piece o between them which is provided with a

page_text: suitable recess o¹ with which to engage the studs or points of engagement d' dª d³ d'
on the wheels. These slots or recesses o' are preferably provided with indiarubber
buffers p in order to obtain a quiet and steady movement, the recesses being grooved
to receive the rubber in the form of a lining.
The front of the part n (Figure 6) is recessed or cut away at n¹ to admit of the
studs d to d entering the recesses o¹. The front of the part m, however, is on the
contrary, considerably enlarged at m³ so as to project beyond or below the part n and
the connecting piece o, and this enlarged part m¹ is rounded (Figure 6) to adapt it to
be engaged by crescent shaped cams fixed on the wheels b c in order to keep
the arms f' to f lifted clear of the studs during the return stroke. The arms f¹ to f*
work in pairs, that is, one pair for the wheel b and the other for the wheel c so that
the cams are required to be fixed two on each wheel, and they are arranged one on
each side of each wheel as shown in Figure 4, the enlarged rounded parts m of the
arms being similarly arranged on opposite sides of the said arms so as to be only
engaged each by its respective cam at the proper moment. The part m of each arm
has also a curved projection or cam q which is arranged to ride on the periphery of
the aforesaid wheels b and c so as to effect at the proper moment during the driving
strokea lifting of the pivoted arms sufficiently to raise the slots o' from off the studs d'
to d'. This will be understood by referring to Figure 1, from which it will be seen
that the arm (for instance) has fully engaged the stud d when the cam 9 of said
arm projects clear of the periphery of the wheel b, whilst when the lever el is
depressed, the arm f' will be pulled into the position of the arm f which is indicated
in dotted lines, in which position it will have been raised clear of the studs as its
cam q bears on the periphery of the wheel b in this position as indicated in dotted
lines. The action of the cams q of all the arms is the same as that just described,
the arm f being lifted clear of the stud d² when the arm f1 engages the stud d' and
vice versa. The other pair of arms f' and f³ work in a similar manner on the studs d³
and d. The said projection or cam 7 may be supplemented by another cam q
both formed in one piece, as shown in Figures 6 and 6^, and adjustable by tilting to
bring either cam into engagement with the wheel so tha by reversing, by means of
an arm r, the front cam q or the rear cam gl may be caused to bear on the wheel b
and serve for raising or fifting up the pivoted arms (f) so that it is possible to
allow the motor to run backwards.
The mode of action of the device is as follows:-
On the descent of the one lever e¹, the recess o¹ of the pivoted arm engages on a
stud or point of engagement d of the one wheel b and turns the wheel about 90°
(Figure 1). The recess o¹ of the second arm then engages with the second stud d².
The moment the second arm f2 is engaged with its stud d², the first arm fl is lifted
up by the cam q, which comes in contact with the periphery of the wheel b and rides
thereon during the further rotation so that the arm f is lifted clear of the stud d¹ as
before described. The second arm f on a further depression of the lever e¹ then
effects a further rotation of the wheel to the extent of a further 90° so that the axle a
has been turned 180°. In the meantime the other lever e² has been raised by the
rack gearing hand the other arms f³ f* come into engagement with the other
studs d d respectively. This lever then descends and a further rotation of 180° of
the axle a is effected in a similar manner by the arms f and f, whilst the first
named arms ff on their upward stroke are held with their recesses o¹ out of
engagement with the studs d d by means of the crescent shaped projections l'
which engage the enlarged part m of the arms and hold the latter up as before
described.
The invention is applicable for the transference of power for mechanical or foot
driving machinery as shown in Figures 1 and 2, and is particularly applicable to
cycles as shown in Figures 7 and 8 and in detail views 9 and 10.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is :-

page_text: 1. A mechanism for converting reciprocating into rotary motion, consisting of a
double elbow lever (e¹) mounted on a spindle (9) aad having a reciprocating motion,
and arms (ff) provided with recesses (o') and so pivoted on the ends of said lever
that said "recesses, owing to the shape of the front ends of the arms and of a
wheel (b) having crescent shape projections (12) mounted on the driving axle,
engage alternately on studs or points of engagement (d' d²) provided on said
wheel (b), and set the driving axle (a) in constant rotation: in combination with a
second similarly shaped and acting mechanism, comprising a double elbow lever (e),
pivoted arms (f3 ), and stud wheel (c), which, under the action of a rack
gearing (h) and toothed segments (2), move in an opposite direction to that of the
other mechanism, the arms being maintained in contact with the wheels (bc) by
adjustable springs (k), substantially as herein before described.
2. The application of the herein described mechanism to the driving of bicycles and
the like substantially as herein before set forth.