Improvements in and relating to Tandem Safety Bicycles.
Year: 1888

page_text: Datef o Application, 27th Oct., 1888
Specification Accepted, 30th Nov., 1888
Improvements in and relating to Tandem Safety Bicycles.
I, FREDERICK MALCOLM DOSSOR, of 339 Beverley Road, Kingston upon Hull, in
the County of Yorkshire, Commercial traveller, 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 :-
My Invention has reference to that class of velocipedes known generally as
"tandem
safety bicycles," which can be made convertible either for one or two riders, and is
devised with a view to overcome the disadvantages hitherto experienced in connection
with machines of this type as heretofore usually constructed. One of the disadvan-
tages hitherto experienced in connection with such machines, is that the strain upon
the neck of the machine-resulting generally from the riders being situated both in
front of the rear or driving wheel-is considerable, and materially interferes with the
free steering and easy manipulation of the machine, especially when travelling over
uneven surfaces of ground; thus proving a source of great danger to the riders should
breakage or accident occur to the neck of the machine, whilst same is being ridden at
a high rate of speed.
In order that my Invention may be the better understood I have appended the
accompanying sheet of drawings in which Figure 1 is a side elevational view of a
machine constructed in accordance with my Invention, and Figure 2 is an enlarged
detached view of the convertible joint hereinafter referred to.
In carrying out my Invention I employ in accordance therewith a tube frame A-
carrying the driving chain and seat for the front rider-extending from the neck a of
the machine, in a curved direction partially over the rear or driving wheel, and ter-
minating in the socket b, supported or retained in position by means of the perpen-
dicular fork B, carried by the axle of the rear or driving wheel. A detachable
continuation A¹ of said tube frame A,-carrying the handles, driving chain, and seat
for the rear rider-is extended partially round the hind part of the rear or driving
wheel, and is connected to the rear end of the tube frame A as hereinafter fully
described. A fixed fork or stay is provided for connecting the lower ends of the
perpendicular fork B to the tube frame A in order to maintain said fork B securely in
position. A detachable tube stay or support D-carrying the chain wheel brackets-
is employed as a means of further supporting and strengthening the rear tube

page_text: .
frame A', and is connected to the perpendicular fork B and main tube frame A by any
suitable means of fastening. The double chain wheel of the rear or driving wheel
carries on its inner teeth the forward driving chain, and on its outer teeth the rear
driving chain.
The construction of the convertible or connecting joint between the main tube
frame A and rear frame A¹ is illustrated in the detached enlarged view Figure 2, in
which the rear end of the main tube frame A is shewn enclosed within the socket b of
the perpendicular fork B hereinbefore referred to. Within the open rear end of the
main tube frame AI insert for about half the length thereof and secure firmly therein,
a metal bar E which is curved to correspond with the formation of the tube
frames A, A'. The remaining half of said metal bar E-which protrudes from the
rear end of said tube frame A-is then inserted within the open end of the tube
frame A¹, and retained securely therein by means of screw bolts or other equivalent
means of fastening.
When the machine constructed in accordance with my Invention is required to be
converted from a tandem bicycle for two riders into a single machine for one rider,
the tube stay D is detached from the main tube frame A and perpendicular fork B.
The rear driving chain is then disconnected from the double chain wheel; the bolts
securing the rear tube frame A¹ to the main tube frame A loosened, and the rear tube
frame A (together with the handles, seat, driving wheel chain and bracket) thus
separated from the other portion of the machine.
From the foregoing it will seen that in accordance with my Invention I am enabled
to ensure that the weight of the riders is equally balanced upon the rear or driving
axle, thus leaving the steering wheel free and easy to manipulate, and at the same
time reducing the strain upon the neck of the machine.
Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to be perfornied, I declare that what I
claim is:
First: The improved convertible tandem safety bicycle substantially as herein
described and shewn.
Second: In the convertible tandem safety bicycle hereinbefore referred to, the
employment of a curved tube frame A, rear tube frame A¹, and connecting joint, (the
latter shewn more particularly in Figure 2), substantially as herein described and shewn
in the accompanying drawings.
Dated this Twentieth day of October 1888.
JAMES STEVENSON,
Gray's Inn Chambers,
20, High Holborn, W.C.,
Agent for Applicant.