Improvement in Bicycle Brakes.
Year: 1898

page_text: Date of Application, 29th July, 1898-Accepted, 18th Feb., 1899
COMPLETE SPECIFICATION.
Improvement in Bicycle Brakes.
We, JOIN MITCHELL DOWNER, of No. 89, Wellington Street West, Pattern
Maker, ARCHIBALD ANDERSON DICKSON, of the Bank of Commerce Building,
Manufacturer, and JOHN KING, of No. 89, Wellington Street West, Pattern
Maker, all in the City of Toronto, in the County of York, and Province of Ontario,
Dominion of Canada, 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:-
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This invention relates to bicycle brakes of that class which are applied through
the sprocket driving wheel by the action of back pedalling, and has for its object
to produce a brake which shall be positive and direct in its action, easily applied
either instantaneously or gradually, and one which shall be simple and cheap in
construction, not liable to get out of order, and one which will not add
materially to the weight of the bicycle, or interfere in any way with its easy
running.
The essential features of my invention consist in a cam fixed upon the crank
axle and a brake-shoe pivotally-connected to the sprocket and adapted to be
thrown into frictional contact with a stationary part of the framing of the
bicycle by the action of back-pedalling.
For full comprehension of the invention reference must be had to the accom-
panying drawings forming part of this specification in which similar letters of
reference indicate like parts in the several figures.
In said drawings Figure 1, represents a longitudinal sectional elevation show-
ing a bicycle crank axle in connection with the hub, sprocket and pedal-cranks
and illustrating the improved brake thereto applied.
Fig. 2, is a vertical sectional elevation taken on the line a, a, Fig. 1, looking
towards the sprocket and showing the cam engaging two brake-shoes separately
pivotted.
Fig. 3, is a view taken on similar lines but showing the two brake-shoes carried
on the same pivot and a different form of returning spring.
Fig. 4 represents another modification on the same line showing the cam with
only one brake-shoe and without a spring.
Figs. 5 and 6, are details showing parts of one crank arm and the sprocket,
and illustrating a modification of the means connecting same to ensure their
co-operation. Referring first more particularly to Figs. 1 and 2, A, represents
the hub formed in one with or connected to the tubing or framing of the bicycle
and provided with any suitable anti-friction devices a, a,. to ensure easy running.
B and B', are tlie pedal-cranks and C, the driving axle all of any approved con-

page_text: struction. 1), is the sprocket fixed upon said axle as usual, and by preference
having formed upon its inner face an annular groove d, to loosely receive the rim
of a tubular extension A', of the hub or framing A. This tubular extension is
preferably somewhat larger in diameter than the main body of the hub and serves
to enclose and protect my improved brake mechanism, which as herein before pre-
mised, consists of one or more brake-shoes E, pivotted at e, to the inner face of
the sprocket D, and a cam F, for operating said brake-shoe or brake-shoes made
in one with or firmly fixed upon the crank axle C.
Connection between the crank B, and the sprocket D), is made by means of the
pin b, fitting into said crank B, and projecting through a curved slot d', formed
in the sprocket D; or this connection may be made in any other convenient way
such as by means of the finger. d, projecting from the inner side of the crank
arm B, and entering a depression, in the web of the sprocket D, as shown in
Figs. 5 and 6 of the drawing or in any other convenient manner, the
other conditions and arrangements being practically the same as hereinbefore
described.
It must be understood that I reserve to myself various forms of arrangement of
the brake-shoes E, in connection with the sprocket D), and tubular extension A¹;
for instance the pivot e, may serve to support and connect two brake-shoes as in
Fig. 3, or one brake-shoe only, as in Fig. 4, or there may be two pivots, one
carrying each brake-shoe as in Fig. 2, or a pivot point might project from one
member into another, or there might be no special pivot between the brake-shoes
and the contiguous surfaces, but reliance be had entirely upon the spring G,
(of which I have shown two modifications) one as shown in Fig. 2 being a bow
spring which bears against the shoulders e¹ of the brake shoes E which it tends
to force inwards, and the other Fig. 3 a circular spring held in grooves formed in
the cam-like projections in the inner sides of the brake-shoes E, and pulled into
an elliptical shape when the brake is applied, so that on the brake-shoes being
released the spring resumes its original shape and thus draws the shoes inwards.
Or any other modified arrangement upon the same principle might be adopted
without departing from my improvement, and other variations of construction
may be substituted without any essential change of structure, or without depart-
ing from the essential principle of the improvement.
-
The operation of my improved bicycle brake may be described as follows:
When a steep down grade may be encountered, or when it is desired at any
time to slow-up, or to quickly. stop the forward movement of the bicycle, a slight
back-pedalling motion is imparted to the pedal-cranks (more especially to that
crank, marked B, immediately adjacent to the sprocket) which retarding-move-
ment of the pedals and their axle, has the effect of operating the cam F, and
bringing its longer surfaces or points into contact with the brake-shoe, or brake-
shoes E, in such manner as to press same into frictional contact with the inner
side of the rim of the tubular extension A¹, of the stationary hub or frame A,
which frictional contact causes the gradual or immediate suspension of progress
of the wheel according to the will of the rider.
Having now particularly described and ascertained the nature of
invention, and in what manner the same is to be performed, I declare that what
my said
I claim is:
1. In a bicycle brake, the combination with the frame, the crank axle, pedal-
cranks and sprocket, of a brake-shoe carried by the sprocket and acting upon a
stationary part of the frame, and a cam or projection fixed upon the crank axle
and brought into action against said brake-shoe by back-pedalling, substantially
as and for the purpose set forth.
2. In a bicycle brake, the combination with the frame, the crank axle, pedal-
cranks and sprocket, of two or more brake-shoes independently pivotted upon and
carried by the sprocket and acting upon a stationary part of the frame, a cam 5
or projection fixed upon the crank-axle for expanding or throwing said brake-

page_text: shoes against such frame, so as to form frictional contact therewith, and a spring
for returning same out of action when the cam is released, or turned in the
reverse direction, substantially. as and for the purpose set forth.
Dated at Toranta 4th day of December 1896
JOHN MITCHELL DOWNEY.
ARCHIBALD ANDERSON DICKSON.
JOHN KING.
Witnesses,
ROBT. A. KELLOND,
E. LONG,
International Patent Bureau,
12, Melinda Street, Toronto, Canada.