Improvements in the Driving and Brake Mechanism of Cycles and the like.
Year: 1899

page_text: Date of Application, 11th Oct., 1899
Complete Specification Left, 11th Aug., 1900-Accepted, 15th Sept., 1900
PROVISIONAL SPECIFICATION.
Improvements in the Driving and Brake Mechanism of Cycles
and the like.
"
I, ERNST GUSTAV HOFFMANN, of Hamlet House, Chelmsford, in the County of
Essex, Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to certain improvements in the form of driving and brake
mechanism frequently employed for cycles and usually known as free wheel"
mechanism one of the objects of my invention being to produce mechanism which
is self contained so that the wheel hub carrying same may be applied to existing
wheels the braking portion of the device necessitating no connection with the
frame of the vehicle as is the case with some forms of these devices.
In carrying out my invention I cause the driving and the braking action to take
place between the same member which in the construction I am about to describe
as an illustration are the sprocket wheel or equivalent part driven from the pedals
and a surface carried by the hub. The contacting surfaces I prefer to make conical
one of them being faced with leather or suitable holding material which may be
so shaped as by corrugations and the like that it will hold securely in the corre-
spondingly shaped part or seat to which it is attached and I cause the loose one
of the two members which may be the sprocket wheel to be forced against the hub
part in the operation of driving by the lateral thrust of a series of balls or their
equivalents working on cam surfaces formed on a part carried by the hub which
thrust is obtained by the sprocket wheel being rotated at a greater speed than the
hub thus causing the balls or the like to ride up on their cam faces and move the
sprocket wheel laterally into contact with the frictional surface carried by the hub.
To the axle is fixedly screwed or attached (and in such a manner that it may be
adjustable) a part having also cam faces on which work balls or their equivalents
the cams being reversely arranged to those on the part carried by the hub. Such
balls also bear against the loose member or sprocket wheel and act laterally on
same, their thrust being obtained by the reverse movement of the loose member
or sprocket wheel obtained by back pedalling which causes the balls to travel up
the cam faces and again press the loose member against the frictional surface of
the hub with a force which can be easily regulated so that the hub and wheel are
braked by this action. The loose member is carried on ball bearings and preferably
on a loose and sliding sleeve carried by a part of the hub such loose member being
kept normally away from the frictional hub surface by the pressure of a spring
which may act for this purpose on the sleeve and in this (its free wheel) position
it is in contact with both sets of balls as above described so that either are ready
to act upon it for driving or braking purposes according as it is driven forwardly
or backwardly.
The part carrying the balls for the driving operation may be in the form of a
disc having cam faces situated in grooves suitable for holding and retaining the
balls which are kept at the highest part of the cam by means of suitable'springs.
The part carrying the balls for the braking purpose may be also in the form of

page_text: a disc the balls being retained on the cam faces by means of a skeleton frame or
cage through openings in which they project a suitable distance such frame or cage
being controlled by a spring or springs the tendency of which is to keep the balls.
at the lowest part of the cams. In one form the spring or springs may be coiled
around a central portion of the disc their free ends being connected to the cage,
suitable stops being provided to limit the movement of such cage.
In one form of my invention I preferably make a chamber in the hub in which
parts of the device comprising the ball bearing of the loose member, the sleeve,
and spring, are located."
It will be seen that the device in question consists of a clutch action so con-
structed that if the loose member is caused to rotate forward at a greater speed
than the driving wheel it will engage with and drive it and that when it is caused
to remain stationary it disengages the driving wheel allowing the latter to rotate
freely and further that when it is caused to rotate backwardly it is forced against
a lateral abutment which in turn causes it to engage with the driving wheel with
the result that it acts as a brake in which the torque exerted upon it by the forward
motion of the driving wheel will be transmitted through the chain or other medium
to the pedals where the exact amount of retarding effect created by the brake will
be felt very accurately the action being the same as that known as "back-pedal-
ling only with the difference that the pedals remain stationary.
Dated this 11th day of October 1899.
PHILIP M. JUSTICE,
Chartered Patent Agent,
55 & 56, Chancery Lane, London, W.C.,
For the Applicant.
Improvements in the Driving and Brake Mechanism of Cycles
and the like.
I, ERNST GUSTAV HOFFMANN, of Hamlet House, Chelmsford, in the County of
Essex, 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:-
My invention relates to certain improvements in the form of driving and brake
mechanism frequently employed for cycles and usually known as "free wheel "
mechanism one of the objects of my invention being to produce mechanism which
is self contained so that the wheel hub carrying same may be applied to existing
wheels, the braking portion of the device necessitating no connection with the
frame of the vehicle as is the case with some forms of these devices.
In carrying out my invention I cause the driving and the braking action to take
place between the same members which in the construction I am about to describe
as an illustration are the sprocket wheel or equivalent part driven from the pedals
and a surface carried by the hub.
I have illustrated in the accompanying drawing the form which I consider at
the present time the most suitable for carrying my invention into effect though
it will be understood that there are various other ways in which the parts may be
arranged and the requisite movements obtained. In these drawings
Fig. 1 is a longitudinal elevation one half being in section of a wheel hub having
my invention applied thereto.

page_text: is a similar view but with the sprocket wheel and attached parts removed.
Fig. 3 is a part elevation and part section of the sprocket wheel and spring con-
trolled bearing detached.
Fig. 4 is an end elevation of the sprocket wheel,
Fig. 5 is a part elevation and part section of the ball cage which effects the
driving.
Fig. 6 is an end elevation of same.
Fig. 7 is a section of the brake disc and connected parts which effect the braking
and
Fig. 8 is a face view of the cam portion of same to show the cam surfaces the
other parts being partially removed.
In the drawings 1 is the usual spindle carrying the footstep 2 screwed up to
washer 3 against the frame fork 4 which is held against the washer 5. On the
spindle is a sleeve 6 having two conical faces forming a race for a series of balls 7
the adjusting cones of which consist of rings 8, 8, adjustable by means of a lock
nut 9 of some suitable type. Such rings and lock nut are contained in the evlin-
drical hub body 10 and the adjustment obtained by the lock nut for the ball bear-
ing described is communicated by means of the sleeve 11 to similar cone rings 8, 8,
at the other end of the hub, the balls 7 bearing on which run on a double cone
faced sleeve 12 on the spindle. The outer ring of the last two rings 8 abuts against
a shoulder of a sleeve 13 having a conical outer face 13 the sleeve being screwed
at 14 to the hub 10. The hub has also an enlarged or expanded extension 15 carry-
ing a double cone 16 which in the case shown is formed in one with the hub but
which may be formed of phosphor bronze or some other suitable metal or befaced
with leather in order to allow it to grip a correspondingly shaped surface formed
in the sprocket wheel 17 or similar part such as a bevel gear if bevel gear driving
is employed. This sprocket wheel consists of a chambered ring having a race for
a series of balls 18 such race having a double coned face while the balls bear upon
a conical sleeve 19 capable of sliding on the sleeve 13 such part 19 being prevented
from slipping away from the balls when the sprocket wheel is detached as shown
in Fig. 3 by a spring wire 20 sprung into a groove in the end of same and the pro-
jection of which above its surface is sufficient to hold the parts together. The
spring pressure on the sleeve '19 forms an automatic adjustment for the bearing.
A coil spring 21 seats in the recess of the hub formed between the sleeve 13 and
extension 15 and tends to press the sleeve 19 forward.
Inside the chambered portion of the sprocket wheel are a series of cam surfaces 22
curved to approximately the curvature of the balls to be used in same. Bearing
on the outer conical face 13 of the sleeve 13 and between same and the cam sur-
faces 22 is a series of balls 24 held in a cage 25 Figs. 5 and 6 consisting of a ring
having a series of holes bored through same in each of which is a ball, the edges
of said holes being burred or turned over to hold the balls in the ring in such a
manner that they may turn freely.
In the outer periphery of this cage is a groove in which seats a spring wire 50
somewhat longer than the groove so that it normally expands from same as shewn
in Figs. 5 and one end of which is turned down into a cutaway portion 51 and
the other end 52 is turned up and is passed into a hole in the sprocket 17 as shown
in Fig. 1. The cage is first placed inside the sprocket when the latter is detached
from the rest of the parts the ends of the spring are put in their places and the
cage is partly rotated to compress the spring and when in this position the balls 24-
will be opposite the deepest points of the cam surfaces 22 so that the cage and
balls (with the sprocket) can be slipped into the space shown in Fig. 2 over the
conical outer face 13 of sleeve 13 into the position shown in Fig. 1 the cage imme-
diately rotating backward and bringing the balls 24 away from such highest points
of the cam surfaces and into jamming position against a lower point of such sur-
faces so that the balls are always kept up to their work as in other free wheel
devices where a spring behind the rollers or balls is usually employed.
Screwed upon the other end of the spindle 1 is a nut 29 having a washer 30

page_text: between it and the other fork 4 which in turn is held against a nut 31 screwed to
the spindle. This nut has an internal conical face 41 Fig. 7 recessed in same and
from this recess projects a pin 42. Loosely mounted on the spindle and sur-
rounding the edge of the nut 31 is a disc 34 having an internal recess 43 formed
in a box like portion 44 of same. Into this recess is forced by compressing it a
powerful split or open spring ring 45 having an edge bevelled to correspond with
the face 41. The pin 42 projects into the open part of the spring 45 and the oppo-
site or inside end of the spring abuts against a washer 46 loose on the spindle the
inside face of which forms with the conical end of the inside of the box part 44 a
track for a row of balls 47 of a ball bearing. The disc 34 has a, series of cam sur-
faces 35 formed in same. such cam surfaces gradually decreasing in depth from one
end to the other and being reversely arranged to the cam surfaces 22 in, the
sprocket 17. A ball 36 rests on each cam surface and is held in place by cage 37
as shewn in Figs. 7 and 8 such cage consisting of a ring having openings therein
formed similarly to the cage 25. This cage is loose on the box like portion 44 of
disc 34 and can rotate thereon.
The balls when at the shallowest points of the cam surfaces project and are then
in contact with the surface 40 of the sprocket wheel.
It will be seen that upon removing one of the nuts at the ends of the spindle
the latter can be unscrewed from the washer 31 and withdrawn so that all the parts
may be removed separately from the hub.
In the driving position an increased or a forward movement of the sprocket
wheel over that of the wheel hub will cause the balls 24 to rise up the cam sur-
faces 22 radially in the direction of the shallowest points of same but as they also
travel upon the conical surface 13 of sleeve 13 the movement is changed as the
balls reach their jamming point to a longitudinal or lateral motion which forces
the cage 25 to the left and drives the conical surfaces of the sprocket wheel 17
into engagement with the part 16 of the hub as shewn in Fig. 1 so that both rotate
together the sleeve 19 and ball bearing being at the same time moved laterally
against the pressure of spring 21.
As soon as the hub runs faster than the sprocket, which is the position when the
nedals are held stationary by the feet the balls 24 move backwardly towards the
deepest points of the cam surfaces the spring 21 forces the sleeve 19 ball bearing
sprocket wheel, and cage, to the right so that the reverse movement takes place,
the sprocket 17 is accordingly withdrawn from contact with part 16 and the hub
and wheel run freely the sprocket being thus brought with its surface 40 into
contact with the balls 36 of the disc 34 which I call the brake cam but without any
action on same as the sprocket is held stationary.
When braking is desired the sprocket is rotated necessarily in the reverse direc-
tion with the result that the movement of same acting on the balls 36 causes them
to travel towards the shallowest point of the cam surfaces 35 so that the sprocket
is moved back laterally into contact again with part 16 (which it will be seen acis
both for driving and braking) and united firmly therewith so that the hub and
sprocket again come into contact and the sprocket acts with a retarding effect upon
the hub the action being controlled by the pedals with the result that the braking
action is analogous to back pedalling in an ordinary machine. It will be under-
stood that the disc 34 for this purpose should be rigidly fixed upon the spindle 1
in order to give the necessary fixed abutment to receive the thrust of the balls 36
and this is practically the case in the arrangement described but I have found it
necessary in providing means for allowing the cycle or vehicle to be moved back-
ward to avoid a possible excess of pressure longitudinally of the sprocket upon
the balls in the cams of the disc 34. This is therefore provided for by the spring
ring 45 which is sufficiently strong radially to hold the disc in position as an abut-
ment firmly enough for braking purposes but which will allow it to rotate to pre-
vent it or any of the parts breaking by an excess of pressure exerted between the
disc and the sprocket this being effected through the pressure exerted on the disc
which through the ball bearing is conveyel onto the inside end of the spring ring 45

page_text: which thus has its bevelled edge forced against the conical face 41 of the nut 31
with the result that the spring is slightly contracted or compressed diametrically
releasing its outwardly exerted pressure on the disc and allowing same to rotate
around the nut 31. The ball bearing has been provided to minimise friction and
to ensure the disc 34 rotating.
The pin 42 projecting into the opening of the spring ring 45 prevents same from
turning so that when expanded and gripping the disc the latter is held to the nut
without possibility of rotation.
The braking pressure applied to dise 34 is insufficient to compress the spring
it being only an excess of pressure which will affect it.
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. A driving and brake mechanism of the class described, in which a driving
and braking pressure is exerted between the same trictional surfaces in a line with
the spindle by alternate lateral pressures directly exerted upon the driving member.
2. A driving and brake mechanism of the class described in which a driving
and braking pressure is exerted between the same frictional surfaces by alternate
lateral pressures directly exerted on the driving member through balls or the like
acting on cam surfaces.
3. The combination of one member adapted to revolve forwardly or backwardly
a second loose member capable of revolving forwardly backwardly or remaining
stationary the spindle and an abutment fixed on same having cam surfaces and
balls or the like moveable thereon adapted to engage with the second loose member
so that the latter may be forced into engagement with the first member when
rotated backwardly and cam surfaces and bails or the like moveable thereon for
also forcing the second member laterally into engagement with the first when the
second member is rotated forwardly substantially as described.
4. In combination a hub a friction surface carried thereby, a loose member hav-
ing a corresponding friction surface, a disc carried by the spindle a series of cam
surfaces on such discs, a ball or the like for each cam surface and a spring for nor-
mally keeping the loose member against the balls of the disc whereby such member
may remain stationary though a backward movement imparted to same will cause
it to force the balls along the cam surfaces and to jam the loose member against
the hub whereby a retarding effect may be exerted on the latter.
5. In combination a loose member, a part in which same is adapted to rotate
a conical sleeve forming part of a bearing adapted to slide on such part a ball race
carried by the loose member, balls between same and the conical part and means for
moving the bearing and loose member substantially as and for the purposes
described.
6. A driving and brake mechanism for cycles operating substantially as de-
scribed.
7. A driving and brake mechanism for cycles constructed substantially as
described and illustrated.
111
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1000