Improvements in Brakes for Bicycles and Similar Vehicles.
Year: 1897

page_text: Date of Application, 14th May, 1897-Accepted, 10th July, 1897
COMPLETE SPECIFICATION.
Improvements in Brakes for Bicycles and Similar Vehicles.
I, JAMES HERBERT BULLARD of 777 State Street, in the City of Springfield,
County of Hampden and State of Massachusetts, United States of America,
Mechanical Engineer, 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 brakes for bicycles or similarly propelled vehicles, and
particularly to that class of brakes operated by the limited rotary movement of
the sprocket-wheel on its hub, the object of the invention being to provide a brake
of little weight, yet capable of exerting great pressure on the surface against
which the brake-shoes are applied to arrest the motion of the vehicle to which
said brake is attached.
And the invention consists in the construction shown and described in the
drawings and specification forming part of this application.
In the drawings forming part of this application,-
Figure 1 is a side elevation of the hub of a bicycle-wheel having the brake
thereon whien forms the subject of this specification, shown in section on one end
thereof, and also showing the stationary case within which the shoes of said brake
revolve.
Figure 2 is an end view of the hub shown in Figure 1, on which said brake is
applied, showing the stationary case partly broken away and also showing the
brake set.
Figure 3 is a perspective view of the end of a wheel-hub to which the brake is
attached, and shows the elements constituting said brake, in separated positions,
in the order in which said parts are assembled.
Figure 4 shows a slight modification of the construction illustrated in the
other Figures.
Referring to the drawings, A represents the hub of the bicycle-wheel which
rotates on an axle B, rigidly held in the frame of the machine in the usual
manner.
a
In applying my improved brake mechanism to said hub, the exterior surface of
the sprocket end thereof is threaded from the spoke flange 2, outward, and the
ring 3, is then screwed thereon up to a bearing against said flange 2.
A thin ring 4, of gun-metal or other good bearing metal, is then passed on
over the end of said hub, which ring, when the sprocket-wheel 5, is in its proper
place, will lie interposed between one side of the web 6, of said sprocket, and the
face of said ring 3.
Said sprocket-wheel 5, is constructed as shown in the drawings, (Figures 2
and 3) with a thin web 6, located midway between the two sides thereof, and has
no screw engagement with the hub of the wheel, but it fits freely on the hub 7,
of the ring 8, which is provided with the flange 9, the face of which, contiguous
to the web of the sprocket-wheel, is parallel with said web and at right angles.
to the hub of the said ring 8. This sprocket has a limited rotary movement on

page_text: the hub 7, of the ring 8, the degree of which movement is determined by the
engagement of the bases 10, of the pins 12, fixed in the web of the sprocket-wheel
and which pins project parallel with the axis of said wheel, outwardly, towards
the enu of the hub, the flange 9 of the ring being cut away, as shown in Figure 3,
to allow said pins to project over the faces of said ring 8. In the drawings three
pins are shown, equidistant from each other, which are rivetted in said web of
the sprocket-wheel. Said pins are provided with the bases 10, of larger diameter
than said pins and which bear on the web 6, of the sprocket and make the latter
as rigid as possible. Before said pins are rivetted into said web 6, the ring 13,
similar to the ring 4, is laid on the web 6, and said pins 12 pass through suitably
located holes therein and are then secured by rivetting, as described.
The bases 10, of said pins 12 bear firmly on said ring 13, permanently securing
the latter against the face of the web 6, on the side thereof opposite to that which
bears against the ring 4.
Thus constructed, the sprocket 5, the ring 13, and the pins 12, constitute
practically one piece which, being placed on the hub of the ring 8, the latter is
then screwed onto the threaded end of the wheel-hub, and the diameters of the
rings 3 and 4 being a little less than the extreme diameter of the web-part of
the sprocket, the said rings fit closely in under the rim 14 of said sprocket; and
thus the bearing surfaces of the parts which serve as clamps between which the
said sprocket-web 6 is secured, are protected thoroughly from grit and dust which
in time might cause wear, if they were not so protected.
When said sprocket as above described is placed on the hub of the ring 8, the
pins 12, attached to the sprocket wheel, lie in the cut-away portions 15, of the said
flange 9 of the ring 8. The cutting away of these portions 15 leaves the said
flange 9 in three sections, each end of each section being curved to conform to
the periphery of the bases 10 of the pins 12, which bases bear against one end of
said sections of the flange 9 when the wheel is driven forward, and move toward
the ends of the next section when the sprocket-wheel is given a rotary movement
on its hub to set the brake, which movement is effected through the chain C, by
back pressure on the pedals.
Near one end of these sections of the flange 9 are located the pins 16. These
pins are, like the pins 12, provided with broad bases 16", whereby they are made
more rigid and are by one end rivetted into suitable holes in the said flange.
These pins 16, have their axes parallel with the axes of the pins 12.
Fitted freely on these pins 16, by one end, are three arc-shaped brake-shoes 17.
Said shoes are made of steel, suitably tempered, and are identical in all respects.
The curve of the outer surface of these brake-shoes conforms absolutely with
the curve of the interior of the rim d, of the stationary case D, which is concentric
with the wheel-hub on which the ring 8 is screwed. The length of the brake-
shoes 17 is somewhat greater than the distance between one of the pins 16 and
that one of the pins 12 next ahead of it, using the word "ahead as indicating
the line of movement of the sprocket-wheel as the machine is being driven forward.
The forward ends of the brake-shoes overlapping the pins 12, (see Figure 2) are
tapered from their point backward on the underside and said tapered or wedge-
shaped ends, rest on the upper or outer side of the said pins.
"
When the ring 8 has been screwed up far enough to clamp the web of the
sprocket-wheel with such force as-to-apply thereto the required resistance to its
rotary movement, the jam-nut 18, is screwed onto the wheel-hub and locks the
ring 8. This jam-nut is made circular in form and is provided with two lugs 18",
projecting from the side thereof over which a spanner of suitable form is fitted
to operate said nut.
The circular form of the nut also permits it to be made of such diameter as will
bring its outer periphery in contact with the inner edges of the pins 12, as shown
clearly in Figures. 1 and 2, and whereby a farther support for said pins is provided
other than their point of attachment to the sprocket-wheel. It will be observed
that said point of support comes under the inner edge of the brake-shoes, and thus

page_text: insures a practically unyielding point of support which enables the pins 12 to
take the great pressure from the brake-shoes when the brake is operated.
Said nut also acts as a support for the pins 16, on which the brake-shoes are
pivotally supported, as said nut bears also on the inside of said pins, though a
little nearer their point of attachment to the sections of the flange 9 on the ring 8,
than it does to the point of attachment of the pins 12 to the web of the sprocket.
The brake-shoes 17 are placed on their pins 16, after the nut has been screwed -
up in place against the ring 8, a portion of the hub end of saia shoes being cut
away to allow the edge of said shoe to fit closely against the side of the flange 9.
This cut in the said end of the brake-shoe is shown in that one of the shoes on the
pin 16, in Figure 3, and is indicated by 17ª.
A similar cut is made on the inner surface of said hub-end of the brake-shoes
to allow for the thickness of the jam-nut, so that the said shoes may be placed
in position, as stated, after the nut has been screwed up to the ring 8.
Figure 2 shows the periphery of the said nut in contact with the inner edge
of the pins 16, for the support thereof as described, and shows the extent to which
salu nut is overlapped by the hub ends of said brake-shoes 17.
In a hub construction, such as is shown herein with the ball-cups in the barrel
of the hub, and the ball-cones 20 adjustable on the axle B, the said ball-cones are
provided with a hub 21, having two parallel sides, which fits into the forked end
of the frame of the machine and is thereby prevented from turning after it has
once been adjusted.
The stationary case D, is made of steel or other suitable metal and has an
annular rim d, the width of which is a little greater than the width of the brake-
shoes 17, which lie within it, and said case is provided with an opening centrally
therein through which the said hub 21 of the ball-cone passes; and as said hub
projects far enough through said case to engage the frame, as described, it is
rigidly held by said engagement with the hub 21, against rotation.
In addition to this means of holding said case against rotation when the rotating
brake-shoes are cammed out against the inside of the rim d, of the said case, a
pin 22, is rivetted thereto projecting therefrom parallel with the axis of the axle B,
of sufficient length to engage the frame of the machine, and may be so placed as
engage the vertical or the horizontal brace thereof. In the drawings it is
shown in contact with the vertical brace (see Figure 1) and dotted in its position
in Figure 2.
to
From the above description, it will be seen that the principal elements of the
herein described brake mechanism consist, first, in a sprocket-wheel having a
limited movement on its hub under a certain determined resistance, and pins on
said sprocket-wheel; second, a flange fixed on the wheel-hub having pins thereon
on which are pivotally supported several brake-shoes by one end, and the opposite
ends of which shoes are provided with tapered ends which rest on the pins on
said sprocket, said flange being fixed on said hub and said sprocket rotatable
thereon; and, third, a. fixed case enclosing said brake-shoes and concentric with
said flange.
When the machine is being driven forward and the chain is moving in the
direction of the arrow in Figure 2, the pius 12, on the sprocket-wheel will be
inoved to a position under the thin point of the tapered end of the brake-shoes,
and said shoes will be free to turn, by the rotation of the wheel, in the case ]).
The bases of the pins 12 will abut against the ends of the sections of the flange 9,
and a positive engagement of the sprocket anl its hub will be thereby effected,
to drive the wheel forward
As scon, however, as any back pressure is put upon the pedal by the rider, the
sprocket-wheel is rotated on its hub to a certain degree in a direction against
the arrow on said Figure 2, and the pins 12 are simultaneously brought into con-
tact with the tapered ends of said brake-shoes 17, forcing them outwardly against
the inner side of the rim. d, of the case D, and the frictional contact of said parts
operates to retard the revolution of the wheel, and by reason of the resistance to

page_text: the rotational movement of the sprocket, it is obvious that the latter will remain
in any position relative to its hub in which it may be placed, until an amount
of force to move it back again to the point from which it was first started is applied
thereto, through the chain, by forward pedalling.
Should there be sufficient wear between the surfaces of the web 6, of the
sprocket-wheel and the rings 4 and 13, and thereby the rotary movement of
the sprocket becomes too free, means for taking up'said wear and maintaining said
resistance as desired, are provided by placing the screws 23 in the ring 3 (shown
only in Figure 3).
These screws pass through said ring and their inner ends abut against said
ring 4, and in case of wear, as above set forth, these screws may be turned up to a
bearing against said ring to put as much pressure against the web of the sprocket
as may be desired.
The wear of the contacting surfaces of the brake-shoes or the rim of the case 1),
takes care of itself, as the pins 12 move further back to engage the tapered ends
of the brake-shoes, as said wearing away of the surfaces takes place. When so
much of the brake-shoes has been worn away that it becomes necessary to replace
them, it is only necessary to remove the rear-wheel from the frame, remove the
old shoes and replace them with new ones, and place the wheel in the frame again.
The entire brake mechanism and case is removable with the rear wheel.
Referring to the modification illustrated by Figure 4, said Figure shows the
brake-shoes in a reversed position from that shown in the other. Figures, viz.,
said brake-shoes are pivotted on the pins in the sprocket-wheel and their tapered
ends bear on the pins in the flange 9.
The purpose of this modified construction is to provide a brake having greater
power than can be obtained by the construction shown in the other Figures of the
drawings, such a construction being in some cases desirable, and it is obviously
within the scope of this invention.
It will be observed that if the brake-shoes are pivotted on the pins in the fixed
flange 9, and the wedge-shaped ends of said shoes rest on the sprocket-wheel pins,
that the said shoes within the non-rotatable case D, rotate thereon point first, and
the tendency of the frictional resistance against said shoes when the brake is set
is to move the sprocket-wheel forward again, thereby disengaging the points of
said brake-shoes from the sprocket-pins 12, and release the brake.
This tendency is overcome, however, by the resistance applied to the rotational
movement of the sprocket relative to said flange 9.
"
With the brake-shoes reversed, however, and the end which was pivotted on
the flange 9, pivotted on the sprocket-pins, as shown in Figure 4, the tendency
of the frictional resistance is to constantly force said shoes further in between the
pins 16 and the rim of the case D, and the sprocket resistance can be so adapted
as to permit a slight movement of the sprocket to take place, resulting in a more
powerful application of the brake than is developed by the act of back-pedalling
which first sets the brake.
This construction is especially valuable for use in very hilly countries, and
especially for riders not skilled in back-pedalling. All danger from the jamming
of the point of the brake-shoe between the rim of the case and the pin on the
flange is obviated by making the wedge or inclined surface on the point of the shoe
sufficiently abrupt to prevent-it.
66
While the term pin" has been used throughout the specification to designate
the pins 12 and 16, on the sprocket-wheel and flange 9, it is obvious that those
two parts could be made with projections thereon integral therewith for supporting
said shoes.
Furthermore the two composition metal disks or rings 4 and 13, can be dispensed
with without affecting in any way the operation of the brake, they being used
only because ease of action between the parts is thereby ensured.
The brake, made as herein described, is light and exceedingly powerful, but as

page_text: the power is applied in planes at right angles to the axis of the hub, no strain is
brought on the bearings of the latter when the brake is operated.
The parts subjected to wear are easily replaced and of trifling cost.
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:-
on said
1. A brake mechanism for bicycles and similar vehicles consisting of a wheel-
hub, a sprocket-wheel having a limited rotatable movement thereon, a flange fixed
on said hub, brake-shoes pivotted by one end on said flange, means
sprocket-wheel for engagement with the free ends of said brake-shoes whereby
they are moved in a plane at right angles to the axis of said hub, a stationary case
enclosing said brake-shoes, and means for moving said sprocket-wheel, substantially
as described.
2. A brake mechanism for bicycles and similar vehicles consisting of a wheel-hub,
a sprocket-wheel having a limited rotatable movement thereon, under a controlled
resistance, a flange fixed on said hub, brake-shoes on said flange, means on said
sprocket-wheel for engagement with the free ends of said brake-shoes whereby
they are moved in a plane at right angles to the axis of said hub, a stationary case
enclosing said brake-shoes, and means for moving said sprocket-wheel, substantially
as described.
3. A brake mechanism for bicycles and similar vehicles consisting of a wheel-
hub, a sprocket-wheel having a limited rotatable movement thereon under a
controlled resistance, a flange fixed on said hub, brake shoes supported on said
flange, the free ends of which brake-shoes are tapered or wedge-shaped, means on
said sprocket-wheel for engagement with the free ends of said brake-shoes whereby
they are moved in a plane at right angles to the axis of said hub, a stationary case
enclosing said brake-shoes, and means for moving said sprocket-wheel, substantially
as described.
4. A brake mechanism for bicycles or similar vehicles consisting of a wheel-hub,
a sprocket-wheel positively engaging said hub and having a limited rotary
movement thereon under a controlled resistance, pins fixed in said sprocket, a
flange fixed on said hub having portions thereof cut away for the reception of the
pins in said sprocket, pins on said flange, brake-shoes supported thereon, and whose
opposite wedge-shaped ends bear on said sprocket-pins, a stationary case enclosing
said brake-shoes and means for rotatably moving said sprocket-wheel on said
wheel-hub, substantially as described.
5. A brake mechanism for bicycles or similar vehicles consisting of a wheel-hub,
a sprocket-wheel having a limited rotary movement thereon under a controlled
resistance, pins fixed by one end in said sprocket, a flange fixed on said hub having
pins therein, brake-shoes pivoted on said pins by one end, and whose free
wedge-shaped ends rest on said sprocket-wheel-pins, means of support for the latter
under said brake-shoes, and a stationary case enclosing the brake-shoes and means
for rotatably moving said sprocket-wheel on its hub, substantially as described.
6. A brake mechanism for bicycles consisting of a sprocket-wheel, a support
therefor, brake-shoes pivotally secured by one end on said support and rotating
therewith, said sprocket-wheel being movable under a controlled resistance relative
to said brake-shoes, 'means on said sprocket-wheel for engaging said brake-shoes
for swinging them in a plane at right angles to the axis of said support, a stationary
case enclosing said brake-shoes, and means for rotatably moving said sprocket-
wheel on its support, substantially as described.
7. A brake mechanism for bicycles consisting of a wheel-hub, or its equivalent,
a fixed flange on said hub, a sprocket-wheel on said hub having a limited rotational
movement relative thereto, a series of brake-shoes, projections on the said fixed
flange and the said sprocket-wheel for supporting the opposite extremities of said
shoes, a non-rotatable case enclosing said brake-shoes, and means for rotating said

page_text: sprocket-wheel on its hub in opposite directions for moving said brake-shoes in a
piane at right angles to the axis of said hub for engaging and disengaging them
from said case, substantially as described.