Improvements in Safety Bicycles.
Year: 1896

page_text: Date of Application, 20th June, 1896-Accepted, 27th Feb., 1897
Improvements in Safety Bicycles.
I, DUILIO NATALI, of 53, Via Arenula, Rome, Italy, Law-student, 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 relates to improvements in safety bicycles and has for its object
to provide a driving gear whereby safety bicycles can be run at a greater speed
in comparison to the exertion of power and without producing the least inconvenience
in the movement to the rider.
And in order that.my invention may be more fully understood I have caused to
be appended hereunto one sheet of drawings marked with letters of reference
indicating like parts in the various figures.
Fig. 1 is a side view at a scale of 1 to 10 of a bicycle provided with my improved
driving gear, and
Fig. 2 is a plan at a scale of 1 to 3 of my improved driving gear separately.
The bicycle (Fig. 1.) has a fore wheel A and a hind wheel B. The upper part-
of the frame does not differ in form from that of bicycles already in use whilst the
under side which forms a very important part of my driving gear represents three
sections. Section C is made of a single bar which is fixed on one end to the tube S
of the machine and with its other ends slightly curved to the axle box H in which
turns upon ball bearings the axles of the chain wheel K and the crank lever L.
The second section C₁ consists of two shafts slightly diverging which at one end
are jointly fixed to the axle box H and at the other end are fixed to the axle box I
wbich contains upon two ball bearings the axles T, T' of the levers R & R'. The
third section C consists also of two slightly diverging shafts which are in a line
with the aforesaid two shafts. These two shafts are fixed at one end to the axle-
box I and their other ends carry the axle upon which the hub J of the hind wheel
turns and to which hub is fastened the small chain wheel K. Rotary motion is
transmitted from the chain wheel K to the small chain wheel K' and to the hind
wheel B by means of the chain D shown in dotted lines.
The levers R, R' which are secured upon the axles T, T' are furnished at their
extremities with the usual pedals P. At an intermediate point, say one third of
their whole length these levers have slots E, in which are lodged upon ball
bearings F the lower ends of the connecting rods N, N1, their upper ends being
jointed by means of studs G. G' respectively to the crank lever L and one of the
spokes of the chain wheel K.
The studs G & G are positioned diametrically opposite to the axle box H.
From the above description and the drawings it will be readily understood that
in depressing one of the pedals P with the foot, for instance the one on the side of
the chain wheel K, the lever R' descends and pulls with it the connecting rod N
attached to the lever R. The connecting rod N¹ turns the chain wheel K until
it is level with the centre of the axle box H. When the lever R' is depressed the
lever R, the connecting rod N and the crank lever L rise until the studs G, G¹ of
the connecting rod N & N¹ meet in the horizontal plane of the centre of the axle
box H. In this position the said levers and connecting rods reverse their
movement. The lever R lowers itself and the lever R raises inactive whilst the
chain wheel continues its movement always in the same direction. The oscillatory

page_text: movement of the levers R, R' is thus transformed into a continuous rotary motion
of the chain wheel which motion is communicated to the hind wheel of the machine
by means of the chain D.
In an ordinary. bicycle the cranks have a length of 0.15 metre with a
multiplication of 1.30, the rider's exertion is 3-30 kilos. In my improved gear the
connecting rods N, N₁ are. jointed to the lever arm L and the arm of the chain
wheel K respectively at a distance of 0-075 metres from the centre of the axle box H.
The throw of the said crank levers is thus half that of the pedal cranks of an
ordinary bicycle and the exertion necessary at G, G' would be double or 6.60 kilos.,
the same as at the studs F. The latter being attached upon the levers R, R¹
at of their length, to depress the latter. the rider must therefore only exert a of
the said power or 2.20 kilos.
By my improved gear I obtain therefore an average reduction of power
of 1:10 kilos. at each depression whilst the speed remains the same.
But should I use the whole power of 3-30 kilos. for each pedal with a proportional
augmentation of the coefficient of multiplication I should obtain an increase of the
speed of one half over the ordinary bicycle.
These advantages I obtain with but a small increase of weight without
diminishing the solidity of the machine and without causing the rider an
inconvenience in the movement of his legs.
In fact it will be readily seen that the added parts are very few, that is the two
levers R, R', the two connecting rods N, N1 and the lever arm L and the bars of
the frame are utilized to mount the axles of the levers R, R' and all these are
securely united together.
I wish to point out that in walking the foot is lifted but little from the ground
with angular position of the legs. The contrary happens by climbing up a ladder
the elevation of one foot in respect to the other is considerably higher with a great
bending of the knee and the angular position of the legs nearly vanishes. Now it
is well known that the first named movement is much easier than the second one
and my improved gear is exactly based upon this principle. The axis of rotation
of the levers R, R is therefore placed perpendicular under the saddle S' in order
to obtain the said angular position of the legs and to diminish as much as possible
the vertical motion so that the movement of the pedals becomes very easy.
If on the other hand I should have favoured the movement of the pedals in
elevation I should have been cbliged to place the centre of rotation of the levers as
far as possible from the perpendicular point of the saddle which would have
occasioned an uncomfortable movement of the legs and a serious inconvenience
through the high elevation of the knee preventing the free manipulation of the
handle.
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-
A driving gear for bicycles consisting of two levers with alternative oscillating
movement, actuating by means of connecting rods, the chain wheel of the bicycle,
characterized by the point of suspension of the said levers being arranged
perpendicularly under the saddle, the whole as substantially described and
illustrated.
Dated this 10th day of June 1906
F. BOSSHARDT & Co.,
4, Corporation Street, Manchester, Agents to Applicant.