Year: 1887

page_text: Date of Application, 18th July, 1887
-Complete Left, 18th Apr., 1888
Complete Accepted, 18th May, 1888
We, ARTHUR MATTHEW MARKHAM, of 345 Edgware Road, in the County of
Middlesex, Bicycle Maker, and GEORGE SHANN, of 3 Park Row, Albert Gate, in the
County of Middlesex, Engineer, do hereby declare the nature of this Invention to be
as follows:-
This Invention relates to bicycles constructed to carry two riders, and consists in
an arrangement whereby the crank shafts, operated by the riders, are capable of
rotation at an angular velocity different from that of the driving, or hind, wheel.
According to this Invention the axle or hub of the driving, or hind, wheel is
hollow, and a crank shaft passes through it provided with cranks and treadles at each
of its projecting ends for being operated by one of the riders. For the other of the
riders a crank shaft is provided, which is mounted in suitable supports, and situated
parallel to the above mentioned crank shaft and having cranks and treadles at each
end. This last named crank shaft is situated between the driving, or hind, wheel and
the steering, or front, wheel. The two crank shafts are connected together so that
they rotate with the same angular velocity or nearly so and their movement of rotation
is imparted to the driving, or hind, wheel by chain or wheel gear of any suitable
description so that the said wheel is rotated at an angular velocity different from that
of the crank shaft passing through the axle or hub of the said driving, or hind,
wheel.
A
1 1
101 1
T "
1007
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C.,
Agents for the said Arthur Matthew Markham
and George Shann.

page_text: Improvements in Bicycles.
We, ARTHUR MATTHEW MARKHAM of 345 Edgeware Road in the County of
Middlesex, Bicycle Maker and GEORGE SHANN of 3 Park Row Albert Gate in the
County of Middlesex, Engineer, 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 Bicycles constructed to carry two riders tandem fashion
and consists in an arrangement whereby the crank shafts operated by the riders, are
capable of rotation at an angular velocity different from that of the driving, or hind,
wheel.
According to this Invention the axle or hub of the driving, or hind, wheel is
hollow, and the crank shaft worked by the hindmost rider passes through this hollow
hub and is provided with cranks and treadles at each of its projecting ends. For the
other rider a second crank shaft is provided which is mounted in bearings carried by
the frame of the machine, the said shaft being situated parallel to the above mentioned
crank shaft and having cranks and treadles at each end. This second crank shaft is
situated between the driving, or hind, wheel and the steering, or front, wheel. The
two crank shafts are connected together by chain gear or by coupling rods so that
they rotate with the same angular velocity or nearly so and their movement of
rotation is imparted to the driving, or hind, wheel by wheel gear of any suitable.
description so that the said wheel is rotated at an angular velocity different from that
of the crank shaft passing through the axle or hub of the said driving, or hind,
wheel.
Figure 1 of the accompanying drawings represents in side elevation a tandem
bicycle constructed according to our invention and the remaining Figures illustrate
arrangements of gear which may be employed in carrying out our said Invention.
Referring to Figures 1 and 2, A is the driving wheel and B the steering wheel.
Through the hollow hub C of the wheel A passes the crank shaft D on the outer ends
of which shaft are keyed the cranks E, operated by the rear rider. The shaft D
rotates in bearings F attached to the frame G of the machine which frame carries
between the driving and steering wheels the bearings for the crank shaft H operated
by the foremost rider. The shafts D and H are shewn as being connected. by a
chain I passing round chain wheels K K' keyed respectively on the shafts D and H.
On the shaft D is fixed a spur wheel L as shown in Figure 2 (which represents in plan
a simple arrangement of multiplying gear) gearing with a corresponding wheel M
fast on à counter shaft N carried in bearings O on the frame G, on which counter
shaft is also keyed another spur wheel P gearing with a corresponding wheel Q fast
on or formed in one with the hub C of the driving wheel A. By varying the relative
sizes of the wheels L M P and Q the angular velocity of the wheel A with respect
to the angular velocity of the crank shafts D and H may be varied as desired.
Figure 3 represents in sectional plan-a modification of the multiplying gear con-
sisting of an arrangement of sun and planet wheels Q and P the wheel Q being

page_text: attached to or formed in one with the hollow hub C whilst the wheel P gearing
therewith is mounted on a spindle p passing through the hollow crank pin R.
The cranks worked by the rear rider are connected with the cranks worked by
the front rider by means of coupling rods T so that both crank shafts are rotated
together and their combined action is transmitted to the driving wheel A through the
gearing P Q. The said coupling rods may carry the treadles as shewn in the
drawing.
Figure 4 represents in sectional plan a further modification wherein the multi-
plying gear is enclosed within the hub C of the driving wheel A. The hub C is
divided vertically into two parts c c but to strengthen the wheel these parts may
be fastened together by any suitable fastening devices. On the crank shaft Ď
which passes through the hollow hub C is fixed an arm a carrying a bevel
wheel in gear with a corresponding wheel Q fixed to or formed on the
interior of the part c of the hub Cand also with a similar wheel d rigidly connected
with the frame G and passing through the portion of the hub into the interior
thereof. On the part of the hub is shewn a chain wheel K which may carry a
chain whereby the two crank shafts can be connected. For the sake of simplicity
plain bearings are shewn in the Drawings but any or all of the rotating parts may
run on ball bearings as is usual in bicycles.
In any bicycle similar to those herein before described provision may be made when
desired for giving to one of the riders a certain amount of lead on the stroke so that
the two pairs of cranks may not be simultaneously at the dead points. When the
cranks are coupled by chain gearing this lead is gained by placing the chain wheels
in the proper positions relatively to each other and to the cranks. When the
cranks are coupled by connecting rods the lead is gained by making the parts of
the crank pins which hold the treadles for one rider eccentric with regard to those
parts of the same crank pins which hold the ends of the connecting rods.
Having now described and particularly ascertained the nature of our invention
we wish it to be understood that we do not restrict ourselves to the particular con-
struction or arrangements of the wheels constituting the gear hereinbefore described
neither do we claim as our invention the application of multiplying gear consisting of
wheels connected by a chain but what we claim is :-
1st. In tandem bicycles having coupled crank shafts the application and use of
wheel gearing such that the crank shaft passing through the hub of the driving
wheel shall impart to that wheel, through the said gearing, an angular velocity
different from that of the crank shaft, substantially as herein before described with
reference to the accompanying drawings.
2nd. In tandem bicycles the application and use of multiplying gear consisting of
sun and planet wheels and means for imparting motion thereto substantially as herein-
before described and illustrated by Figure 3 of the accompanying drawings.
3rd. In tandem bicycles the application and use of inultiplying gear arranged
within the hub of the driving wheel and means for imparting motion thereto
substantially as hereinbefore described and illustrated by Figure 4 of the accompanying
drawings.