Improvements in Bicycle Brakes.
Year: 1897

page_text: Date of Application, 23rd Nov., 1897-Accepted, 29th Jan., 1898
Improvements in Bicycle Brakes.
I, ABRAM WILLIAM DUCK, of Oakland, County of Alameda, State of California,
U.S.A., Gentleman, 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 relates to improvements in bicycle brakes, and it consists essen-
tially in the application of rollers journaled to rotate in planes which intersect
the plane of travel of the wheel diagonally, so that the pressure of the rollers upon
the rim or tire of said wheel will act to retard its motion.
It also consists in mechanisin by which said rollers are retained in position with
relation to the framework of the machine, and normally held out of contact
with the tire; mechanism by which the rollers are forced into contact when it is
desired to use the brake; and in details of construction which will be more fully
explained by reference to the accompanying drawings, in which
Figure 1 is a side elevation of the front portion of a bicycle with my brake
attached to it.
Figure 2 is a top view of the same, the steering post being broken away.
Figure 3 is a longitudinal section through one of the brake rollers.
The object of my invention is to provide a brake which is especially intended
for use upon the rubber tires of bicycles which are easily worn and destroyed by
the friction of any ordinary form of rubbing brake, and by the peculiar arrange-
Bent of the rollers constituting the frictional surface I am enabled to transfer
the rubbing and wearing friction to other surfaces which are not easily destroyed,
but which are easily replaced when worn, so that the tire is practically relieved of
wear from this cause. This brake may be applied to either front or rear wheel,
may be actuated by a brake lever extending along the handle bar, or by the foot
if applied to the front wheel, or by any suitable or well known connecting
mechanism if applied to the rear wheel, but I prefer to employ a short curved
lever fulcrumed centrally and movable in the line of travel of the machine, said
lever being provided with projections upon each side so that either one or both
hands can be employed to actuate it and through it the brake.
In the drawings as here shewn, A represents this brake lever which is fulcrumed
upon a pin at which forms one of the fastenings of a clamp B. This clamp is
fixed to the turnable steering-post of the machine so as to be movable with it.
The lever A is a bell-crank lever, and the upper part is so bent that it extends
rearwardly above the top of the handle bar O. At the rear end are two arms a
which extend a short distance each way along the handle bar so that the rider
may, while still holding the bar, use either one or both hands or thumbs to press
the lever forward in the line of travel of the machine.
The lever at the lower end is of that class known as bell crank and the
short arm is fulcrumed at 6 to the upper end of the extension rod or plunger C.
This rod or plunger connects at the lower end with the shafts or axles of the rollers
which form the brake proper.
This plunger rod is made in the usual manner, of two parts CD), with a locking

page_text: device at e, so that the rod may be extended or shortened to fit the brake to
machines having different lengths of steering posts.
From the lower end of the plunger rod, the shafts or axles f diverge both down-
wardly and forwardly from the bottom of the post D, thus standing at an obtuse
angle therewith.
Upon these shafts are mounted the friction rollers H which are preferably made
of properly tempered rubber mounted upon interior cores, with sleeves F which
are turnable upon the shafts f.
Upon the outer ends of the shafts are fitted washers G which are here shewn
as screwing upon the ends of the shafts so that they may be properly adjusted
with relation to the rollers.
Against the inner faces of these washers the cores of the rollers abut and when
the brake is applied, the pressure upon the rollers forces them outwardly and
increases the frictional contact with the washers proportionately to the pressure
applied.
The rollers are as here shewn, essentially cylindrical at the outer ends and curved
inwardly in an approximately semi-globular form where they meet or abut
against each other.
This brings the outer periphery of the rollers in contact with the tire of the
machine and the rotation of the wheel in its line of travel causes the rotation of
the rollers in planes which intersect the plane of rotation of the wheel diagonally,
and this rotation of the rollers in different planes from the plane of the wheel,
causes the rollers to bind strongly upon the wheel tire, at the same time pressing
them outwardly against the frictional washers G.
In order to prevent these washers from turning, to hold the rollers normally
out of contact with the tire, and to support the rollers and the lower end of the
plunger shaft without the necessity of an additional clamp, I have shewn a spring i
which has a central bight in line beneath the bottom of the steering post to which
it may be secured by a screw and washer.
From this bight the arms and the spring bend outwardly in each direction just
behind the forks R of the machine against which this portion of the spring rests.
Exterior to the forks they are coiled, thence returning part way toward the
centre, and thence extending forwardly between the forks of the machine as plainly
sliewn in the bottom view.
The outer ends of the spring are bent so as to enter holes d formed in the
washers G and thus lock these washers in place so that they will not be revolved
and screwed either on or off the shafts f by the action of the rollers. The clasticity
of the spring holds the rollers up from the wheel, but allows them to be pressed
down upon it by the action of the lever.
The transverse rear portion of the spring resting against the rear of the forks,
holds the lower part of the plunger rod and the rollers in place while the front
ends of the spring hold the washers, and the washers may be adjusted at any
time by withdrawing these ends and screwing the washers on or off as may be
desired.
This spring performs the triple duty, first, of forming an elastic support for
the brake rollers and the lower end of the plunger rod, serving to keep the rollers
normally out of contact with the bicycle tire. Secondly, the transverse portion
of the spring resting against the rear portion of the bicycle forks prevents the
rollers and plunger rod from being pressed forward by the friction of the tire,
thus avoiding the use of any other clamp at this point: and, thirdly, they act as
a lock to prevent the frictional washers exterior to the brake rollers from being
turned.
The plunger rod being thus supported by the spring at the lower end and by
the lower projecting portion of the brake lever at the upper end, is maintained
close to and parallel with the steering head without the necessity of any other
attachment.
An important feature is the formation of the arms of the axle so that they

page_text: incline not only downward each side of the tire, but forward at an obtuse angle
with each other, and with the foot of the plunger rod. This brings the pressure
portion of the rollers upon the tire at such an angle with its line of travel, that
the rollers turn at a corresponding angle with the line of movement of the tire,
thus producing a compressing action upon the tire without a frictional rubbing
or dragging at this point which would cause the tire to be worn out in a short
time. It also produces an outward pressure which forces the outer ends of the
rollers against the frictional washers where the retarding friction takes place.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:—
1. In a bicycle brake, a plurality of rollers journaled upon shafts extending
downwardly and forwardly at an obtuse angle with each other and means for
forcing the rollers into contact with the tire.
2. In a bicycle brake, a plunger rod having shafts at its lower ends extending
in opposite direction downwardly and forwardly at an obtuse angle, rollers on
said shafts, frictional washers on the outer portions of the shafts to receive the
outward pressure of the rollers and means for forcing the rollers in contact with
the tire.
3. In a bicycle brake and in combination with the brake rod, an actuating bell
crank lever connected with the rod and having its free end curved over and behind
the handle bars so that the lever lies in the direction of the line of travel of the
machine.
4. In a bicycle brake, rollers journaled upon shafts extending downwardly and
forwardly at an obtuse angle from their junction, a plunger rod fixed to the
junction of said shafts extending upwardly having its upper end connected
with one arm of a bell crank lever, the other arm of said lever extending upwardly
and bent backwardly above the handle bar of the machine and having transverse
extensions, a clamp fixed to the stem and below the handle bar, a fulcrum pin
upon which the angle of the bell crank lever is turnable whereby the brake is
applied by moving the lever in the line of travel of the machine.
5. In a bicycle brake, a vertical movable plunger rod having the upper end
connected with a brake lever, the lower end carrying downwardly and forwardly
diverging shafts, rollers journaled upon said shafts and having cylindrical con-
tact surfaces to press upon the tire at each side of the central line, circular screw
threaded washers fitting and adjustable upon the ends of the shafts to form
frictional contact with the outer ends of the rollers, a spring having its forward
ends adapted to enter perforations in the washers, whereby the rollers are normally
supported out of contact with the tyre and the washers are prevented from turn-
ing, said spring extending rearwardly between the forks of the bicycle and bent
transversely across behind said forks having a central portion and means for
securing it centrally within the fork crown, whereby said spring forms a yielding
support to normally hold the rollers out of contact with the tire, a stop to prevent
the rollers and plunger rod from being moved forwardly when the brake is
appied, and means for locking the frictional washers to prevent their rotation.
Dated this Twenty third day of November 1897.
For the Applicant,
GEDGE & FEENY,
Chartered Patent Agents, 60, Queen Victoria Street, London, E.C.