Improvements in or relating to Brake and Driving Mechanisms for Bicycles and other Vehicles.
Year: 1899

page_text: Date of Application, 9th Mar., 1899--Accepted, 22nd Apr., 1899
COMPLETE SPECIFICATION.
Improvements in or relating to Brake and Driving Mechanisms for
Bicycles and other Vehicles.
A communication from GEORGE E. MCELROY, of Elmira, New York, United
States of America.
I, ALFRED JULIUS BOULT, of 111, Hatton Garden, in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
This invention relates to improvements in brake mechanisms in which
the braking power is applied to the hubs of the driving wheels of bicycles and
other vehicles, in which the retarding power on the drive mechanism, (as in
back pedalling), serves to impede the forward movement of the driving wheel
proportionate to the amount of retarding force applied; and the objects of the
improvements are, first, to provide means whereby when the driving power is held
stationary, the driving wheel will be left free to turn forward, as in coasting;
and second, to provide means for applying friction to said driving wheel to retard
its motion when the driving power is turned backwards.
These objects are attained by the mechanism illustrated in the accompanying
drawing, in which:
Figure represents a side elevation of a driving wheel hub attached to the
rear fork end of a bicycle and having the improvements applied thereto;
Figure 2, a plan view of the same with a portion of the dust guard broken
away to disclose the brake mechanism;
Figure 3, a longitudinal section on lines
Figure 4;
in Figure 2 and z-z in
Figure 4, a transverse section on line y-y in Figure 3;
Figure 5, a detail showing the stationary disc plate detached and in reverse
position; and
Figure 6, details showing modifications of the clutch devices.
Similar letters refer to similar parts throughout the several views.
A represents the axle of the driving wheel, and B the hub. In the present
instance, the hub B is extended out to the left and provided with the right and
left hand screw threads B1 and B2. Upon these threaded portions of the hub
are screwed collars carrying the friction discs C and D. These collars are
securely locked together when in place by the trend of the screw threads, and can-
not be turned in either direction by the action of the sprocket wheel. The two
friction discs form an annular run-way or bearing in which are mounted the
sprocket wheel and the several parts of the brake mechanism. The sprocket
wheel E is loosely mounted in this bearing with one face adjacent to the friction
disc C. The other, or outer, face of the sprocket wheel is provided with a collar
like projection E, the face of this collar being provided with three incut wedge
bearings J, J, J. Adjacent to the outer friction disc D is located a stationary

page_text: disc-plate F, the outer periphery of which is provided with an inward and out-
ward turned flange which extends over the periphery of the friction disc D
and the collar E', forming a dust guard for the enclosed mechanism.
An arm N
extends forward from the stationary disc-plate F and is clamped to the rear
frame brace by the screw clamp O, or other suitable fastening device. Between
the stationary disc-plate and collar of the sprocket wheel is the rotary disc-
plate G.
One face of this rotary disc-plate is provided with out-cut wedge bear-
ings Kopposite the collar E. The outer face of the rotary disc-plate is provided
with three recesses opposite the wedge bearings in which are located spring
actuated dogs or pawls L, adapted to engage a series of clutch teeth M cut on the
inner face of the stationary disc-plate F. Between the friction disc C and the
sprocket wheel, and between the friction disc I) and the stationary disc-plate are
located fibre washers I and H to prevent the wear of metal upon metal when the
brake action is applied. The inner periphery of the sprocket wheel E is pro-
vided with a series of clutch teeth P (see Figure 4), adapted to be engaged by the
spring actuated dogs or pawls Q located in sockets on the collars of the friction
disc C.
In operation, when the driving power is given a forward movement, (as by
the pedals in a bicycle), the sprocket chain will drive the sprocket wheel E for-
ward, or to the right, and one of the clutch teeth 1' will be brought into engage-
ment with a dog Q on the collar of the friction disc C. The sprocket wheel will
then be locked to the hub of the driving wheel and will give it a forward motion.
When the driving power is held stationary, the sprocket wheel E will also be-
come stationary, and the driving wheel will continue its forward movement, the
dogs permitting the forward motion of the hub. During the forward motion
of the sprocket wheel, the wedge bearings K on the rotary disc-plate will run
into the corresponding bearings Jon the sprocket wheel, and the rotary disc-
plate will be carried around with the sprocket wheel, the dogs L then clicking
past the clutch teeth on the stationary disc-plate F. When the sprocket
wheel becomes stationary, the rotary disc-plate will also become stationary; the
sprocket wheel, rotary disc-plate, and stationary disc-plate remaining in their
then relative positions until the sprocket wheel is moved forward or back. In
this position of the mechanism, the driving wheel is left free to revolve, and the
vehicle will move forward without the application of power. A hill may thus
be coasted in bicycling without removing the feet from the pedals. If it is
desired to apply the brake, a small backward turn of the pedals, or other driving
power, will turn the sprocket wheel backward, and, the rotary disc-plate being
prevented from backward rotation by the engagement of the dogs L with the
clutch teeth M on the stationary disc-plate, the wedge bearings J will run upon
the wedge bearings K, thus forcing the inner face of the sprocket wheel E against
the friction disc C, and the outer face of the stationary disc-plate Fagainst the
friction disc D; and the braking friction may thereafter be increased or
diminished by the degree of motion in either direction imparted to the sprocket
wheel E. It will be seen that a very little lateral motion is imparted to the
sprocket wheel so that the drive chain will maintain substantially true align-
ment at all times. In order that there may be as little lost motion as possible
the sprocket wheel is provided with an odd number of clutch teeth and the hub
of the friction disc with an even number of dogs. As illustrated in Figure 4,
there are 9 of the clutch teeth 1' and four of the dogs Q. For the same reason
the stationary disc-plate F is provided with twelve of the clutch teeth N and
the rotary disc-plate with three of the dogs L.
While the method of attaching the brake mechanism to the hub, as illustrated
in the drawing, is preferred, other means of attachment may be employed.
especially where the mechanism is to be applied to a driving wheel the hub of
which will not permit of this arrangement, and my correspondent does not there-
fore, wish to be confined to the precise structural arrangement of these parts as
shown herein. Also, in place of the spring actuated dogs Q and L engaging

page_text: the clutch teeth P and M, rollers running in incut wedge bearings may be
employed for the same purpose, as illustrated in Figure 6, where y represents
the rotary disc-plate and f the stationary disc-plate. The stationary disc-plate,
in this case, is cut with a wedge bearing inclined in the opposite direction to the
clutch teeth as shown in Figure 2. 7 represents the roller, and it will be readily
understood that when the rotary disc-plate moves forward the roller will run
down the incline and permit said forward motion; but when the rotary disc-
plate is moved backward by the action of the sprocket wheel, the roller will run
up the wedge bearings and lock ƒ and g together. In the same way e in Figure 6
represents the spocket wheel and e the collar of the friction disc C. When the
sprocket wheel is moved forward, the roller Q will run out on the wedge bearing
and lock e and together. When e is held stationary or moved backward, the
roller will run down the wedge bearing, allowing and the driving-wheel hub
to turn forward.
Having now particularly described and ascertained the nature of the said in-
vention as communicated to me by my foreign correspondent, and in what
manner the same is to be performed, I declare that what I claim is :—
1. The combination, with a driving wheel and driving means of a sprocket
wheel loosely mounted on the hub of the driving wheel, a clutch mechanism
between the hub and sprocket wheel, a friction disc secured to the hub a
stationary disc plate between the sprocket wheel and friction disc, and a clutch
and wedge mechanism between the stationary disc plate and the sprocket wheel,
whereby the driving wheel is released from the sprocket wheel when the driving
means is stationary and whereby friction is applied to the friction disc to retard
the driving wheel when the driving means is reversed.
2. The combination with a driving wheel and driving means of a friction disc
secured to the hub of the driving wheel a sprocket wheel loosely mounted on the
hub, a stationary disc plate, a rotary disc plate loosely mounted on the hub
between the sprocket wheel and stationary disc plate a clutch mechanism between
the sprocket wheel and rotary disc plate, and a clutch mechanism between the
rotary disc plate and stationary disc plate whereby the driving wheel is driven
forward, released or retarded respectively as the sprocket wheel is driven forward
held stationary or turned backward.
3. The combination with a driving wheel and driving means of two friction
discs secured to the hub of the driving wheel and forming an annular run-way
or bearing, a sprocket wheel and a rotary disc plate loosely mounted in said
run way between the friction discs a stationary disc plate between the rotary
disc plate and one of the friction dises a clutch mechanism between the sprocket
wheel and hub a wedge bearing between the sprocket wheel and rotary disc plate
and a clutch mechanism between the rotary disc plate and stationary disc plate
whereby the driving wheel is driven forward released or retarded respectively
as the sprocket wheel is driven forward held stationary or turned backward.
4. A brake mechanism of the kind described provided with a clutch device
substantially as described and illustrated in Figure 6 of the accompanying
drawings.
5. The complete brake and driving mechanism for bicycles and other vehicles
substantially as described or illustrated in Figs. 1, 2, 3, 4 and 5 of the accom-
panying drawings.
T 111
CIL L
2 1000
BOULT & WADE,
Agents for the Applicant.