Improvements in Brake Mechanism for Bicycles and other Vehicles.
Year: 1897

page_text: Improvements in Brake Mechanism for Bicycles and other Vehicles.
I, PERRY ERNEST DOOLITTLE, formerly of Toronto, in the County of York, and
Frovince of Ontario, Dominion of Canada, but now of 1, Little Park Street,
Coventry, in the County of Warwick, Physician, do hereby declare the nature of
this invention to be as follows:-
My invention relates to improvements in brake mechanism for bicycles and
other vehicles, and it consists of certain improvements upon the invention set
forth in the Specification of my application for Letters Patent No. 11635 of 1896.
The improvements set forth in that specification relate to a friction brake con-
nected with and operated by the driving means, and provided with locking means
to lock the brake in any position into which it may be moved by the operation
thereof, until such locking action is overcome by the exertion of sufficient pressure
upon the driving means. My present improvements while embodying many of
the principal features of my former brake, have for their objects to improve and
strengthen the locking means referred to above, to increase the holding force
and stiffen the action of the same, and to provide means whereby such action and
holding force can be regulated to any desired degree in a simple and convenient
manner, as I shall now proceed to describe chiefly with reference to its applica-
tion to bicycles driven by pedals, but its application to motor cars or vehicles
driven by power will be obvious.
My invention is illustrated in the accompanying drawings in which-Fig. 1 is
a side elevation showing part of a bicycle with driving means comprising a pedal
shaft, chain, and sprocket wheels and my improved brake mechanism applied
thereto; Fig. 2 is a plan of the axle and hub of the driving wheel with sprocket
wheel and brake mechanism; Fig. 3 shows partly in side elevation and partly in
vertical section the sprocket end of the axle and hub with sprocket wheel and
brake mechanism shown in Fig. 2. Fig. 4, an inner face view of the sprocket
wheel with clamp attached; Fig. 5, is a detail view of the clamp alone; Fig. 6,
is an outer face view of the sprocket wheel; Fig. 7, is an inner face view of the
laterally movable brake disc; Fig. 8, is an inner face view of friction disc; and
Fig. 9, is a detail plan view of the sprocket wheel and brake disc, the former
having part broken away to show the engaging teeth on the two parts.
Referring to the drawings, A, A¹ are the spindle and hub respectively, of a rear
driving wheel, B the sprocket end of the hub, and D is the sprocket wheel on the
said hub. The sprocket end B of the hub is provided on its periphery with pro-
jections or lugs a² and the sprocket wheel D with recesses on its inner cir-
cumference. When the sprocket wheel is slid on to the hub, the projections a

page_text: of the latter enter the recesses of the former. The sprocket is then pushed
beyond the projections to its seat against a collar and.turned so as to bring its
recesses out of engagement with and behind the lugs, which then serve to hold
the sprocket wheel against lateral movement on the hub on which however it is
capable of partly turning.
On its outer face the sprocket wheel D is provided with teeth or sections E in
the form of inclines, the highest parts of which terminate in abrupt inwardly
bevelled shoulders 6. F is a brake disc mounted on the hub and provided on its
inner face with similar teeth E¹ and shoulders . These respective teeth or
sections together form a clutch, and when set together the shoulders 61 of the
respective teeth engage, their inner bevelled faces meeting, and the inclined faces
of the teeth being in close and continuous contact, so that in their locked position
the thinnest portions of the brake disc rest against the thickest portions of the
sprocket wheel and vice versa. The disc F is provided with recesses fl (Fig. 7)
which, when this disc is placed on the hub, engage with the projections a³, so that
the disc is by this engagement made to rotate with the hub, but is also at the same
time capable of moving laterally thereon. The brake disc is arranged to partly
extend into the sprocket wheel so that the engaging teeth E E¹ are enclosed by
the said wheel as shown.
H is a disc plate having an inwardly extending annular rim h¹ and rigidly :
mounted on the spindle A. Within the rim the face of the plate is provided
with a frictional surface, which may be composed of leather, rubber or other
suitable frictional material. The outer plain face f2 of the brake disc F acts as
a friction plate and is adapted to enter within the rim of the disc H and impinge
against the said disc, as hereinafter described. R is a pin or lug projecting from
the outer face of the disc H so as to act against the forked frame S for the purpose
of preventing the disc from turning with the brake disc when the pressure is
applied. This pin or lug R may conveniently extend through the fork §¹.
M is a circular metal collar or band secured to the inner face of the sprocket D by
means of a screw », passing through an arm or projection of the band. This
arm or projection is bent outward beyond the edge of the band as shown in
Fig. 3, and is adapted to fit into a depression in the sprocket so as to be flush
with the adjacent surface thereof. The engagement of this depression and the
arm or projection of the band would alone be sufficient to keep the sprocket and
band in close contact and prevent their separate rotation, but to render certain
the continuous engagement of these parts I prefer to employ the additional screw
connection above described. The band M may be provided on its inner cir-
cumference with a suitable frictional material n², for example paper fibre, and is
arranged to overlap and bear against the peripheral surface of the collar r on the
hub, thereby constituting a friction clamp or lock for the said sprocket and brake
mechanism, as and for the purpose hereinafter described.
At a point on its circumference directly opposite the arm or projection n' the
band clamp is split or opened and there provided with two lugs oo, which are
joined by an adjusting and retaining screws. By means of this split formation
of the band and the adjusting and retaining screw for connecting the ends of the
band, it will be seen that the pressure of the said band upon the hub can be
adjusted to any desired degree.
The operation of the device is as follows:-In the act of back pedalling or
reversing the movement of the wheel to check its forward direction the power
exerted on the sprocket wheel tends to give the wheel a differential movement
relatively to the hub, that is to turn it slightly backward on the
hub. This reverse action causes the engaging teeth E E¹ of the
respective faces of the sprocket wheel and brake disc to ride upon each other and
force the brake disc out against the face of the friction disc H. The pressure of
the brake disc against the friction disc increases as the inclines rise or slide upon
each other. The same backward movement of the sprocket wheel overcomes the
resistance of the band clamping caused by its frictional contact with the collar r,

page_text: and the clamp is turned back on the hub with the sprocket wheel. As soon as the
backward pressure on the sprocket is relieved, the pressure of the clamp upon
the collar of the hub is such as to still hold the sprocket wheel turned back and
the brake disc against the friction disc until released by the exertion of a forward
pressure sufficient to cause a differential movement of the sprocket wheel and hub
in the reverse direction and turn the sprocket wheel into its forward position in
which it will be held by the clamp. Upon this reverse action of the sprocket
wheel, the inclines engage and positively withdraw the brake disc out of action
and keep it locked out of action as in my former construction of brake mechanism
herein before referred to. The adjusting screws allows the clamping action of
the band clamp on the collar to be varied to any desired degree to suit require-
ment as in the arrangement of brake apparatus described in my former specifica-
tion so that when the sprocket wheel and brake disc are locked together in their
normal condition, the resistance of the friction clamp against the hub prevents
any accidental operation of these parts due to slight and unintentional back
pressure on the driving means, and holds them in this position until some definite
force, which should be considerable, is applied in the reverse direction on the
driving means, to overcome such resistance and produce the differential movement
of the sprocket wheel and hub required to put the brake in action. The resistance
of the friction clamp also serves to prevent the brake when " on" being accidentally
taken off. In such a construction the strength of the locking action of the said
clamp can be regulated to accommodate the style of vehicle employed and the
character of the route to be traversed, and in the case of a bicycle can be adjusted
to the strength and skill of the rider. When desired, the band can, by means of
the screws, be tightened up sufficiently to prevent the operation of the brake
altogether.
It will be seen that the same brake action of the two discs carrying the engaging
inclined teeth can be accomplished whatever may be the means of reversing the
rotary disc and whether the same is a sprocket disc or not whenever such action
is sufficient to force the inclined teeth upon each other, the amount of braking
friction produced being controlled by the amount of back pressure exerted. The
action of the brake is entirely automatic, being controlled by and corresponding
to the pressure exerted by the rider in checking the forward movement of the
wheel in back pedalling.
The parts of the brake are made to fit so closely as to wholly exclude dust and
dirt.
As will be obvious an adjustable clamping device acting in the manner described
can be constructed in various forms. Also that instead of being connected to the
sprocket wheel and arranged in frictional rubbing contact with the hub, it may
be connected to the brake disc F and be in frictional rubbing contact with the
boss D of the sprocket wheel D as shown in Fig. 10.
It will also be obvious that brake apparatus according to my invention may be
applied in connection with the sprocket wheel D on the pedal or main driving
shaft D2, the fixed friction disc H being then carried by the lower bracket
bearing 13 and the brake disc being located between it and the sprocket wheel D'.
The brake disc is arranged to slide laterally on a collar that is fast to the pedal
shaft and that is provided with raised lugs to cause the brake disc to rotate with it.
The sprocket wheel is mounted loose on the shaft between the crank and the collar
and is formed with teeth to engage with similar teeth on the movable brake disc
through which it is rotated from the pedal shaft. This arrangement however is
not so advantageous as that hereinbefore described, as should the chain break no
braking action can be exerted upon the machine.

page_text: Improvements in Brake Mechanism for Bicycles and other Vehicles.
I, PERRY ERNEST DOOLITTLE, formerly of Toronto, in the County of York, and
Province of Ontario, Dominion of Canada, but now of No. 1, Little Park Street,
Coventry, in the County of Warwick, Physician, do hereby declare the nature
of this invention and in what manner the same is to be performed to be par-
ticularly described and ascertained in and by the following statement:―
My invention relates to improvements in brake mechanism for bicycles and
other vehicles, and it consists of certain improvements upon the invention set
forth in the Specification of my application for Letters Patent, No. 11635 of 1896.
The improvements set forth in that specification relate to a friction brake con-
nected with and operated by the driving means, and provided with locking means
to lock the brake in any position into which it may be moved by the operation
thereof, until such locking action is overcome by the exertion of sufficient pressure
upon the driving means. My present improvements while embodying many of
the principal features of my former brake, have for their objects to improve and
strengthen the locking means referred to above, to increase the holding force
and stiffen the action of the same, and to provide means whereby such action and
holding force can be regulated to any desired degree in a simple and convenient
manner, as I shall now proceed to describe chiefly with reference to its applica-
tion to bicycles driven by pedals, but its application to motor cars or vehicles
driven by power will be obvious.
My invention is illustrated in the drawing accompanying my Provisional
Specification to which I refer and in which-Fig. 1 is a side elevation showing
part of a bicycle with driving means comprising a pedal shaft, chain, and sprocket
wheels and my improved brake mechanism applied thereto; Fig. 2 is a plan of
the axle and hub of the driving wheel with sprocket wheel and brake mechanism;
Fig. 3 shows partly in side elevation and partly in vertical section, the sprocket
end of the axle and hub with sprocket wheel and brake mechanism shown in Fig. 2.
Fig. 4, an inner face view of the sprocket wheel with clamp attached; Fig. 5 is a
detail view of the clamp alone; Fig. 6 is an outer face view of the sprocket wheel;
Fig. 7 is an inner face view of the laterally movable brake disc; Fig. 8 is an inner
face view of the friction disc; and Fig. 9 is a detail plan view of the sprocket wheel
and brake disc, the former having part broken away to show the engaging teeth
on the two parts.
Referring to the drawings A, A1 are the spindle and hub respectively, of a rear
driving wheel, B the sprocket end of the hub, and D the sprocket wheel on the
said hub. The sprocket end 13 of the hub is provided on its periphery with
projections or lugs a² and the sprocket wheel D with recesses ² on its inner cir-
cumference. When the sprocket wheel is slid on to the hub, the projections a
of the latter enter the recesses of the former. The sprocket wheel is then pushed
beyond the projections to its seat against a collar and turned so as to bring its
recesses out of engagement with and behind the lugs a² which then serve to
hold the sprocket wheel against lateral movement on the hub on which however it is
capable of partly turning.
On its outer face the sprocket wheel D is provided with teeth or sections E
(Fig. 6) in the form of inclines, the highest parts of which terminate in abrupt
inwardly bevelled shoulders 61 (Fig. 9). F is a brake disc mounted on the hub
and provided on its inner face with similar teeth E¹ and shoulders 6. These
respective teeth or sections together form a clutch, and when set together the
shoulders 61 of the respective teeth engage, their inner bevelled faces meeting,

page_text: and the inclined faces of the teeth being in close and continuous contact, so that
in their locked position the thinnest portions of the brake disc rest against the
thickest portions of the sprocket wheel and vice versa. The disc F is provided with
recesses (Fig. 7) which, when this disc is placed on the hub, engage with the
projections a², so that the disc is by this engagement made to rotate with the hub,
but is also at the same time capable of moving laterally thereon. The brake disc
is arranged to partly extend into the sprocket wheel so that the engaging teeth E E¹
are enclosed by the said wheel as shown.
His a disc plate having an inwardly extending annular rim h and rigidly mounted
on the spindle A. Within the rim the face of the plate is provided with a
frictional surface i, which may be composed of leather, rubber or other suitable
frictional material. The outer plain face f2 of the brake disc Facts as a friction
plate and is adapted to enter within the rim h of the disc H and bear against the
said disc, as hereinafter described. R is a pin or lug projecting from the outer
face of the disc H so as to act against the forked frame $ for the purpose pre-
venting the disc from turning with the brake disc when the pressure is applied.
This pin or lug R may conveniently extend through the fork S.
of
The construction and arrangement of the parts hereinbefore described are similar
to that of the corresponding parts of the brake mechanism shown and described in
my said former specification.
M is a circular metal collar or band secured to the inner face of the sprocket
wheel D by means of a screw n, passing through an arm or projection n of the
band. This arm or projection n' is bent outward beyond the edge of the band as
shown in Fig. 3, and is adapted to fit into a depression in the sprocket wheel so
as to be flush with the adjacent surface thereof. The engagement of this
depression and the arm or projection of the band would alone be sufficient to keep
the sprocket wheel and band in close contact and prevent their separate rotation,
but to render certain the continuous engagement of these parts I prefer to employ
the additional screw connection above described. The band M may be provided
on its inner circumference with a suitable frictional material n², for example
paper fibre, and is arranged to overlap and bear against the peripheral surface of
the collar on the hub, thereby constituting a friction clamp or lock for the said
sprocket wheel and brake mechanism, as and for the purpose hereinafter described.
At a point on its circumference directly opposite the arm or projection n', the
band clamp is split or opened and there provided with two lugs oo, which are
joined by an adjusting and retaining screw s. By means of this split formation
of the band and the adjusting and retaining screw for connecting the ends of the
band, it will be seen that the pressure of the said band upon the hub can be
adjusted to desired degree.
any
The operation of the device is as follows:-In the act of back pedalling or
reversing the movement of the wheel to check its forward direction, the power
exerted on the sprocket wheel tends to give the wheel a differential movement
relatively to the hub, that is to turn it slightly backward on the hub. This
reverse action causes the engaging teeth E. E' of the respective faces of the sprocket
wheel and brake disc to ride upon each other and force the brake dise out against
the face of the friction disc H. The pressure of the brake disc against the friction
disc increases as the inclines rise or slide upon each other. The same backward
movement of the sprocket wheel overcomes the resistance of the band clamp M
caused by its frictional contact with the collar r, and the clamp is turned back
on the hub with the sprocket wheel. As soon as the backward pressure on the
sprocket is relieved, the pressure of the clamp upon the collar r of the hub
is such as to still hold the sprocket wheel turned back and the brake disc against
the friction disc until released by the exertion of a forward pressure sufficient to
cause a differential movement of the sprocket wheel and hub in the reverse direc-
tion and turn the sprocket wheel into its forward position in which it will be held
by the clamp. Upon this reverse action of the sprocket wheel, the inclines b
engage and positively withdraw the brake disc out of action and keep it locked

page_text: out of action as in my former construction of brake mechanism herein before
referred to. The adjusting screws allows the clamping action of the band clamp
on the collar to be varied to any desired degree to suit requirement so that, as
in the arrangement of brake apparatus described in my former specification when
the sprocket wheel and brake disc are locked together in their normal condition,
the resistance of the friction clamp against the hub prevents any accidental opera-
tion of these parts due to slight and unintentional back pressure on the driving
means, and holds them in this position until some definite force, which should
be considerable, is applied in the reverse direction on the driving means, to over-
come such resistance and produce the differential movement of the sprocket wheel
and hub required to put the brake in action. The resistance of the friction clamp
also serves to prevent the brake when on being accidentally taken off. In
such a construction the strength of the locking action of the said clamp can be
regulated to accommodate the style of vehicle employed and the character of the
route to be traversed, and in the case of a bicycle, can be adjusted to the strength
and skill of the rider. When desired, the band can by means of the screws, be
tightened up sufficiently to prevent the operation of the brake altogether.
"
It will be seen that the same brake action of the two discs D and F carrying
the engaging inclined teeth can be accomplished whatever may be the means of
reversing the rotary disc and whether the same is a sprocket disc or not whenever
such action is sufficient to force the inclined teeth upon each other, the amount of
braking friction produced being controlled by the amount of back pressure exerted.
The action of the brake is entirely automatic, being controlled by and correspond-
ing to the pressure exerted by the rider in checking the forward movement of the
wheel in back pedalling.
The parts of the brake are made to fit so closely as to wholly exclude dust and
dirt.
As will be obvious an adjustable clamping device acting in the manner described
can be constructed in various forms. Also that instead of being connected to the
sprocket wheel and arranged in frictional rubbing contact with the hub, it may
be connected to the brake disc F and be in frictional rubbing contact with the
boss of the sprocket wheel D as shown in Fig. 10.
It will also be obvious that brake apparatus according to my invention may be
applied in connection with the sprocket wheel D' on the pedal or main driving
shaft D3, the fixed friction disc H being then carried by the lower bracket
bearing and the brake disc being located between it and the sprocket wheel D¹.
The brake disc is arranged to slide laterally on a collar that is fast to the pedal
shaft and that is provided with raised lugs to cause the brake disc to rotate with
it. The sprocket wheel is mounted loose on the shaft between the crank and the
collar and is formed with teeth to engage with similar teeth on the movable brake
disc through which it is rotated from the pedal shaft. This arrangement however
is not so advantageous as that hereinbefore described, as should the chain break
no braking action can be exerted upon the machine.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what 4
I claim is:-
1. In combination with the driving wheel and driving means of a bicycle or
other vehicle, brake mechanism arranged on the said driving wheel and connected
with and operated by the driving means, and a frictional locking clamp
mounted on the hub of the said wheel and adapted to normally prevent the opera- 5
tion of the said brake mechanism and to lock it when so operated, substantially
as described.
2. Brake mechanism mounted on a suitable support and connected with and
operated by the driving means of a bicycle or other vehicle to which the brake
mechanism is applied, a locking clamp on the said support, the said clamp being. 5
provided with an inner frictional surface to engage the said support, and means

page_text: whereby the pressure of the said clamp can be adjusted, the said clamp being
adapted to normally prevent the operation of the said brake and to lock it when
so operated, substantially as described.
3. In combination with the driving wheel and driving means of a bicycle
or other vehicle, a friction disc mounted on the axis of said wheel, a second
disc mounted on a support and directly connected with the driving means, a
brake disc on said support between said driven disc and friction disc, means to
force the said brake disc against the friction disc to retard the forward movement
of the vehicle, and a band clamp secured to said driven dise and bearing
against the hub of said driving wheel to normally prevent the engagement of
the said brake disc and friction disc and to lock them when so engaged, substantially
as described.
4. In combination with the driving wheel and driving means, of a bicycle or
other vehicle a disc to which the driving means are applied, a brake mechanism
connected with said driven disc, the said brake mechanism being operated
by the reverse movement of the said driving means, a circular band clamp engag-
ing the said driven disc, a pressure regulating screw joining the ends of said
clamp, and a rim on the hub of said wheel on which the said clamp bears when
the brake is operated, substantially as and for the purpose described.
5. In brake mechanism of the kind herein before referred to for bicycles and
other vehicles, a band clamp constructed arranged and operating substantially
as hereinbefore described with reference to and shown in the drawings referred to.
Dated this 5th day of January 1898.
For the Applicant,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.