Improvements in Tandem Bicycles.
Year: 1897

page_text: Improvements in Tandem Bicycles.
I. CHARLES WILLIAM POYNDER ALLEN, Retired Commander Royal Navy, Green-
bank, Porth, St. Columb Minor, Cornwall, do hereby declare the nature of this
invention to be as follows:-
Tandem bicycles of the present form have two serious structural defects namely
(1) they have an exceedingly long wheel base, that is to say, the distance between
the wheels is very great and (2) the entire weight of the forward rider and the
greater part of the weight of the after rider are between the wheels. This not
only brings an undue or unfair strain upon the frame which consequently has
to be made unnecessarily heavy, but it also causes a great waste of power in
driving and thus necessitates a comparatively small wheel and low gearing.
Now one object of my invention is to obviate or minimize the defects above
referred to and with this object I so construct the bicycle that the riders are
placed respectively in front of and behind the driving wheel but with sufficient
preponderance of weight in front of the said wheel to ensure that the front wheel
shall steer efficiently. As nearly all the weight of the riders comes on one wheel,
the distance between the wheels may be comparatively short, the frame can be
lighter and more compact and a larger driving wheel with higher gearing may
be driven at the same expense of power as in tandem bicycles of the ordinary con-
struction.
My invention also includes an improved arrangement of gearing hereinafter
described.
The manner in which I may carry out the invention is as follows:-I carry back
the frame of the machine to a point somewhat behind the rear or driving wheel
and I mount the rear saddle on this rear extension. I mount the front saddle at a
point which is at or near the front line of the driving wheel. Forks are carried
from the upper part of the frame near the respective saddles to the back and front
pedal crank axles respectively and to the gland or sleeve in which the axle of
the driving wheel revolves. There is a fork leading from the front of the upper
part of the frame to the front wheel and to this fork is jointed a fork or stay
connected to the front pedal axle. Stays connect the two pedal axles with the
gland or sleeve of the axle of the driving wheel.
In order to prevent any risk of the bicycle falling backwards a small wheel may
be suspended behind clear of the ground.
My gearing comprises two comparatively short endless chains, the one leading
from a wheel on the axle of the driving wheel to the front pedal wheel and the
other leading from a wheel on the axle of the driving wheel to the rear pedal wheel.
Preferably these two chains are respectively on the right and left hand sides of
the bicycle and there will then be a chain wheel on each end of the axle of the
driving wheel.
2211 .
T 1
100%

page_text: I, CHARLES WILLIAM POYNDER ALLEN, Retired Commander Royal Navy, Green-
bank, Porth, St. Columb Minor,, Cornwall, 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:-
1
This invention relates to tandem bicycles that is to say bicycles which are
designed to be propelled by two or more riders placed behind one another in the
vertical plane of the wheels.
Tandem bicycles of the present form have two serious structural defects namely
(1) they have an exceedingly long wheel base, that is to say, the distance between
the wheels is very great and (2) the entire weight of the forward riders and the
greater part of the weight of the rearmost rider are between the wheels. This not
only brings an undue or unfair strain upon the frame which consequently has
to be made unnecessarily heavy, but it also causes a great waste of power in
driving and thus nécessitates a comparatively small wheel and low gearing.
Now one object of my invention is to obviate or minimise the defects above
referred to and with this object I so construct the bicycle that the last two riders
in order of place are placed respectively in front of and behind the back or driving.
wheel but with sufficient preponderance of weight in front of the said wheel to
ensure that the front wheel shall steer efficiently. As nearly all the weight of
the riders in a bicycle for two riders comes on one wheel, the distance between the
wheels in the case of a bicycle for two riders may be comparatively short,
the frame can be lighter and more compact and a larger driving wheel with
higher gearing may be driven at the same expense of power as in tandem bicycles
of the ordinary construction.
My invention also includes an improved arrangement of gearing hereinafter
described.
The manner in which I may carry out the invention in the case of a bicycle for
two riders is as follows:-I carry back the frame of the machine to a point some-
what behind the back or driving wheel and I mount the rear saddle on this rear
extension. I mount the front saddle at a point which is at or near the front line
of the driving wheel. Forks are carried from the upper part of the frame near
the respective saddles to the back and front pedal crank axle brackets respectively
and also to the bearing carrying the axle on which the driving wheel revolves.
There is a fork leading from the front of the upper part of the frame to the axle
of the front wheel and to this fork is jointed a fork or stay connected to the front
pedal crank axle bracket. Stays connect the two pedal crank axle brackets with
the bearing carrying the axle of the driving wheel.
In order to prevent any risk of the bicycle falling backwards a small wheel may
be suspended behind clear of the ground.
My gearing comprises two comparatively short endless chains, the one leading
from a toothed wheel on the axle of the driving wheel to the front pedal chain
wheel and the other leading from a toothed wheel also on the axle of the driving
wheel, to the rear pedal chain wheel. Preferably these two chains are respectively
on the right and left hand sides of the bicycle and there will then be a toothed
wheel on each end of the axle of the driving wheel.
In applying my invention to a tandem bicycle for more than two riders, I con-
struct the rear portion of the frame, and I arrange the saddles, pedal brackets &c.
and chain driving gears in substantially the same manner as herein before
described with reference to a tandem bicycle for two riders. I then construct the

page_text: forward portion of the frame and arrange the saddles, pedal backets &c. for the
additional riders together with the necessary additional chain driving gears, in
front of the two riders first mentioned in the manner usually practised at present,
that is to say, the propelling force of each additional rider is transmitted from
his pedal crank axle by means of chain gear to a chain wheel on the pedal crank
axle of the rider placed immediately behind him, whilst the last rider but one
and the rearmost rider of the total number of riders drive the back or driving
wheel of the bicycle. in the manner hereinbefore described.
In order that my invention may be better understood I have in the accompany-
ing drawings shown how a bicycle may be constructed according to my invention;
in particular the manner in which the riders are relatively placed and the method
in which motion may be imparted to the cycle. In the accompanying draw-
ings A A are the seats or saddles, BB are the handles, CC is the frame, DD are
the chain wheels (shown in the drawing with independent chains EE connected
with the axle of the driving wheel F) one on each side of the wheel. If it is
desired to have a tandem cycle for 3 riders instead of two the additional seat is
placed in front and the wheel base is increased to allow of the third saddle being
placed in front.
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. An improved tandem cycle comprising a frame or support so constructed and
arranged that the two riders (or the last two riders as the case may be) are carried
respectively in front of and behind the axle of the rear wheel, in combination with
a system of chain gearing for the two (or last two) riders, wherein two chains are
employed, said chains passing round their respective crank wheels and each
gearing independently with the rear wheel, substantially as herein before described.
2. The special arrangement of chain gear for the two (or last two) riders,
wherein two chains are employed, said chains passing round their respective
crank wheels and each gearing independently with the rear wheel of the cycle,
substantially as hereinbefore described.
3. The improved construction of tandem cycle herein before described, whether
provided with the particular chain gear set forth, or with other driving gear.
Dated this 27th day of Anril 1898
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London, Chartered Patent Agents.