Improvements in Bicycles.
Year: 1894

page_text: Date of Application, 15th Nov., 1894
Complete Specification Left, 14th Aug., 1895-Accepted, 21st Sept., 1895
Improvements in Bicycles. -
I, JOSEPH THACHER CLARKE of Boston, Massachusetts, a citizen of the
United States, but at present residing at 3 College Terrace, Harrow, Middlesex,
Architect, do hereby declare the nature of this invention to be as follows:-
This invention relates to safety bicycles of that type in which the front wheel is
driven by a geared axle, while the back wheel is turned from side to side for the
purpose of steering.
In such machines the steering or turning of the back wheel has hitherto been
effected by means of radial arms projecting from the fork of the back wheel, and
connected by rods to similar arms projecting from that straight steering post or
axis which is turned by the direct action of the handles.
My invention has for its purpose to obviate the necessity of such connecting rods,
or other intermediate parts, by so arranging and constructing the frame of the
machine that the handle-bar is attached to a main steering post or backbone which
forms a direct prolongation of the fork of the back wheel. Thus the back wheel is
rigidly, and without connecting links of any kind, affixed to the forked projection
of the straight steering tube, and is moved thereby through the direct action of the
handles, without the danger of backlash.
In carrying my invention into effect in a safety bicycle for a single rider,
I construct the beforementioned steering post as the backbone of the machine, the
inclination of which determines the rake of the back wheel. Two forks from the
axis of the front wheel are connected with this backbone; the one at the juncture
of the saddle support or pillar, the other just above the commencement of the fork
of the back wheel. Thus the body of the frame assumes, in side view, the shape of
a triangle, having one of its sides, namely that represented by the steering post or
backbone, prolonged in both directions: upwards to the handle-bars, and downwards,
in fork, to the back wheel.
My invention is likewise applicable to front driving, rear steering, tandem, safety
bicycles, the steering in this case being effected by the back rider. In such tandem
machines, constructed in accordance with my invention, the frame may be so
extended that the back rider drives a chain-connected sprocket-wheel on a bracket
of the usual type, while the forward rider drives directly upon the geared axis of
the front wheel.
Dated this 15th day of November 1894.
I, JOSEPH THACHER CLARKE, of 3 College Terrace, Harrow, Middlesex,
Architect, 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 safety bicycles of that type in which the front wheel is

page_text: driven by a geared axle, while the back wheel is turned from side to side for the
purpose of steering.
In such machines the steering or turning of the back wheel has hitherto been
effected by means of radial arms projecting from the fork of the back wheel and
connected by rods to similar arms projecting from that short straight steering post
which is turned by the direct action of the handles. Or the back wheel has been
attached to a separate vertically hinged frame which has been deflected for the
purpose of steering by means of a horizontal connecting rod working at right
angles to the axis of the said rear frame. These machines, described in publications,
have, however, not been seen on the road, and are apparently not successful in
practice.
My invention has for its purpose to obviate the necessity of such connecting rods
or other intermediate parts, by so arranging and constructing the frame that the
handle bar is attached to a main steering post or backbone which forms a direct
prolongation of the fork of the back wheel. Thus the back wheel is rigidly, and
without connecting links of any kind, affixed to the forked projection of the straight
steering tube, and may thereby be moved through the direct action of the handles,
without being liable to the disadvantageous effects of backlash.
In carrying my invention into effect in a safety bicycle for a single rider
I construct the beforementioned steering post as the backbone of the machine, the
inclination of which determines the rake of the back wheel. Two forks or struts
from the axis of the front wheel are connected with this backbone: the one at the
juncture of the saddle support or pillar, the other just above the commencement of
the fork of the back wheel. Thus the body of the frame assumes, in side view, the
shape of a triangle, having one of its sides, namely that represented by the steering
post or backbone, prolonged in both directions: upwards to the handle bar, and
downwards, in fork, to the back wheel.
In this straight steering post, forming a direct connection between the back
wheel and the handles, lies the gist, and will be found the chief advantage, of my
invention. By the adoption of this principle of construction the frame is simplified
in design, and decreased in the number of its tubes, closely approximating in
outline to that equilateral triangle which will theoretically secure the greatest
obtainable strength in proportion to the weight of the materials employed.
Moreover the drive upon the axle of the front wheel,-obviating the necessity of a
separate bracket and its appurtenances of chain and sprocket wheels, is effected
under the most favorable conditions, inasmuch as the axis of the driven front wheel
is fixed in relation to the frame and to the rider seated upon it. Thus, as in a
safety bicycle with separate main bracket, there is no tendency of the pressure
applied to the pedals to affect the steering, and no loss of power through a side
thrust and deflection of the driving wheel, requiring to be taken up and counter-
acted by the pull of the hands upon the steering bar.
In more particularly describing means for carrying my invention into effect
I will have reference to the appended drawings, in which
Figure 1 is a side view, and Figure 2 is a top view or plan of a bicycle
embodying the improvements in question.
In these two figures like reference numerals designate like parts.
The triangle of the frame is formed by the backbone or steering post 1,-the
front fork, 2, 2, which runs from the axis of the front wheel to the saddle support,-
and the approximately horizontal lower fork, crossbars, or struts, 3, 3, which
connect the axis of the front wheel with the lowest point of the undivided
backbone. The tubes of the backbone i work one within the other, in the manner
now customary for the shorter steering posts of rear-driven diamond frame safety
bicyles, and consist of a rotatory steering tube supported on ball bearings at the
extremities 4 and 5 of the backbone cover tube.
It may be noted in this connection that one of the advantages of bicycle frames
constructed in accordance with this invention is the fact that these supporting
bearings 4 and 5 of the steering post are situated further apart, and hence secure

page_text: greater rigidity to the inner tube, than is the case in bicycles having the divided
diamond frame at present in general usage.
The front fork 2, 2, and the struts 3, 3, are firmly affixed to the cover tube of the
backbone by means of brazed double lugs, or equivalent jointings, as is familiar in
practice. The inner steering tube is rigidly attached, above, to the steering bar 6,
which may be made adjustable by the usual screw-nut fastening, and below, by
means of a suitable brazed crown, to the fork, 7, 7, more or less curved, of the back
wheel 8. At the lower front corner of the frame triangle, namely at the juncture
of the front fork, 2, 2, and the struts 3, 3, is the axle bearing, 9, of the front or
driving wheel 10. This driving wheel is speeded by means of a gear, 11, which
may be of any suitable design, as is well understood. Motive force is applied to
this gear by the pedal cranks 12, 12, and pedals 13, 13. The rider is seated upon
the saddle 14, which may be upheld by the saddle pin 15, the double prongs of this
pin being inserted into the ends of the front fork tubes 2, 2, and adjustably secured
thereto by screw-nut attachments, as is shown in the appended illustration; or the
saddle itself may be affixed directly to the inclined backbone 1, by any of the means
hitherto adopted for this purpose in the case of ordinary bicycles.
In propelling a bicycle constructed in accordance with my invention, the back
wheel 8 will be deflected from side to side by means of the steering bar 6, which is
grasped at its extremities by the handles, 16, 16. When this steering bar is
rigidly attached to the back wheel, as has been above described, and as is preferred
in practice, the action of steering will be the reverse of that which obtains in the
case of bicycles at present in use: for instance, when the right handle of the
steering bar is drawn towards the rider, the machine will turn towards the left,-
not towards the right. This reversal of direction in the steering, (which may aptly
be compared to the difference between tiller steering and helin-wheel steering in a
boat), not in itself a disadvantage. Should it, nevertheless, be desired to adapt
a rear steering bicycle so that it may agree in the direction of its handle pull with
bicycles of the type at present in use, this may be effected by detaching the
steering bar from its rigid connection to the backbone, and causing the former to
work upon the latter through the intervention of cogs, which will reverse the
rotation, as will be readily understood by those skilled in the art. This change is,
however, disadvantageous, inasmuch as it complicates the parts and decreases the
security and freedom from backlash of the steering gear. It is, moreover, in no
wise necessary, since the difference in the direction of the steering pull is quickly
mastered even by riders who have accustomed themselves to instinctively deflect
the handles of the front steering machines at present in vogue. Hence this detail
of an intervening cogged reversing gear between the steering handle and the
deflected wheel is not claimed as a part of the present invention.
It will be obvious that the principle of my invention, namely the deflection of a
back wheel by a straight steering post, is directly applicable to two-seated bicycles,
known as tandems, as well as to such machines for a single rider as that above
described by way of example. This application to front-driving rear-steering
tandem machines involves no essential changes in those parts herein claimed as
features of novelty. In the construction of such double seated bicycles an
extension of the triangular frame may be provided by a forward diamond, the
foremost rider driving direct upon the gear of the front wheel, while the back
rider drives upon a bracket transmitting its power to the axis of the front wheel by
means of the customary appurtenances of chain and sprocket-wheels. In this
arrangement the steering of the tandem devolves upon the back rider, seated
above the steering post, a division of duties which is generally regarded as
advantageous.
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. In a bicycle driven by a front wheel, the axis of which is fixed relatively to

page_text: the frame, the combination with a rear steering wheel of a straight backbone or
steering post, forming a direct connection between the rear wheel and the steering
handles, substantially as herein before described.
2. In a front-driving rear-steering bicycle, the construction of a triangular frame
formed by the combination of a straight steering post or backbone, 1, a front
fork 2, 2, and a lower fork, crossbars or struts, 3, 3, substantially as hereinbefore
described and illustrated in the appended drawings.
Dated this 14th day of August 1895.
JOSEPH THACHER CLARKE.