Improvements in Cycle Brake Mechanism.
Year: 1899

page_text: Date of Application, 27th June, 1899-Accepted, 2nd Sept., 1899
COMPLETE SPECIFICATION.
Improvements in Cycle Brake Mechanism.
I, OLAF l'IHLFELDT, of 172, Golden Hillock Road, Small Heath, in the City.
of Birmingham, 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 cycle brakes of that class in which retarding pressure
is applied to the rim of a 'free" rear or driving wheel by the rider back-
pedalling, and is, in part, an amplification or development of the improvements
in such brakes described in the specification of my application for Letters Patent
dated the 13th day of January 1899 No. 819.
The objects of my present invention are to simplify the construction and
arrangement of back-pedalling rim brakes, to provide an efficient form of
22
take
off spring for giving the return movement to the parts when the braking
pressure is relieved and to provide the mechanism with suitable stops for pre-
venting excessive application of the brake and to determine the position which
the blocks or contacts shall assume relative to the rim when the brake is off.
Figure 1 of the accompanying drawing represents an elevation of one form of
cycle brake mechanism constructed according to this invention, the parts of
the machine to which the same is applied being shown in section. This view
shows the parts in the positions they assume when the brake is full on.
Figure 2 represents the said mechanism in plan.
Figure 3 is a view showing the system of levers by which movement is com-
municated from the clutch in connection with the driving crank axle to the
frame connected with the brake shoes.
Figure 4 is a separate view of the clip which carries the bearings of the spindle
of the said system of levers.
The same letters of reference indicate corresponding parts in Figures 1 to 4.
a, a are a pair of brake blocks, adapted to contact with the opposite sides of
the inner periphery of the rim 6 of the free driving wheel 61. Each block is
fitted to a shoe a¹, connected to the lower end of a rocking arm. a, pivoted
at a³, to a clip a', embracing a chain stay c, of the framing, with both of the
arms a², being connected together so as to move in unison, by means of a yoke
or fork like frame d, whose opposite branches d¹³, are respectively jointed at their
ends, to the said arms, whilst the yoke itself is connected through the medium
of a brake-pressure moderator e, to the system of power transmitting levers
hereinafter described.
Thus, the screwed stem d³, proceeding from the yoke is adjustably secured to
the moderator casing e', within which the inner end of a slide or draw bar e³, is
located with the outer part passing through, and being guided by, the ring nut or
closure ³, screwed into the open end et, of the said casing, which is connected to
the said slide by a coiled moderator spring e, disposed between the collar e,
of the latter and the inner side of the nut e³, carried by the former.
Arranged in connection with the crank axle f, of the machine is a ring f,
which, when a rider back pedals, is operatively connected with the said crank
037

page_text: axle by a suitable clutch and thereby caused to make a partial rotation in the
direction indicated by the arrow in Figure 1. This movement is communicated
through a link g, to an arm or lever h, whose upper end is made fast to a spindle
or axis i, mounted in sleeved bearings 2, 3, carried by an adjustable clip, adapted
to embrace the seat tube member c', of the bicycle, and from the part of the spindle
crossing the gap, between the said bearing sleeves, a second arm or lever j,
depends and its lower end is connected at j, to the slide or draw bar of the
brake-pressure moderator e, so that the pull transmitted to the arm his con-
veyed through the lever j, to the draw bar of the moderator, whose spring
modifies its intial effect before communicating it through the casing of the
moderator, the rod or stem d³, and yoke d, to the levers carrying the brake
blocks, which are thus put on gradually or progressively instead of the full
retarding power of the brake being immediately applied and suddenly checking
the wheel as might occur if no moderator device was interposed in the system.
To prevent the brake being applied to an excessive degree, I secure to the fram-
ing by means of a clip ¹, a stop k, arranged within the path of the lever h, and
so adjusted relative thereto that when the maximum braking pressure is being
applied to the wheel rim, the edge of the said lever comes against the said stop
and is thereby rendered incapable of further forward movement.
To take off the brake and effect the return movements of the several parts
when braking pressure is relieved by the rider resuming forward pedalling or
taking the pedals to their intermediate inoperative position, I provide a take off
spring m, encircling the sleeve of the seat tube clip, with one end m¹, being
male relatively fast by engaging in a hole, in the lug or car 26, of the said
clip whilst the other end m², is connected in like manner with the lever or arm h,
the arrangement being such that when the said lever is rocked forwardly on the
application of the brake, the coils are closed and the spring thereby made active
exerts itself to rock the lever backwardly and so give the required return move-
ment to the other parts when brake pressure is relieved.
As this spring, in expanding, operates to take the brake blocks away from the
wheel rim, I provide, for the purpose of determining the normal distance between
the said blocks and the rim, a set pin n, adjustable within the end of a short arm
or extension 2, of the lever j, to which it is locked by a nut n², and by the impinge-
ment of its inner end ³, against the flat 7, of the clip, it forms a stop which
prevents the backward movement of the parts beyond a predetermined extent
Figure 5 represents a bicycle of the free wheel type fitted with my improved
pedal-operated back wheel rim brake but showing the brake frame fitted to the
back stays instead of to the chain stays as in the former arrangement.
Figure represents, upon an enlarged scale, portions of the said bicycle show-
ing more clearly the arrangement of the said brake and its operating mechanism.
Figure 7 is a view showing the brake frame (which is mounted behind the
back stays of the machine) in elevation and the casing of its take-off spring in
section.
Figure 8 is a sectional view upon the dotted line & Figure 7 and looking down-
wards.
Figure 9 represents, partly in elevation and partly in vertical section, some
of the component parts of the brake dis-assembled.
Figure 10 is another view showing in section the moderator and the double-
acting swinging stop provided in connection with this form of brake.
Figure 11 represents a cross section of Figure 10 upon the dotted line ..
Figure 12 is a topside plan of the said stop separately, and
Figure 13 is an underside plan thereof.
The same letters of reference indicate corresponding parts in Figures 5 to 13.
In this modification, the brake blocks a, a, are arranged, as before, to contact
respectively against the opposite edges 6 of the rim b, of a free rear or driving
wheel, and are fitted within shoes a¹, attached to the lower ends of the arms or
branches d, of a horse-shoe shaped brake frame d, disposed behind the chain

page_text: stays c, of the machine. This frame is raised or lifted so as to bring its blocks
into contact with the wheel rim, the operating mechanism by which this is
effected being arranged as follows:-
The crank axle f, has in conjunction with it, a rotable ring or equivalent f',
5 adapted to be operatively connected by means of a suitable clutch with the said
axis and thereby, rotated in the direction indicated by the arrow when the rider
back pedals. A link g, couples this ring to the draw bar e², of a spring-organized
brake pressure moderator e, interposed between it and a connecting rod i, pro-
ceeding upwardly behind the seat tube c', of the machine and being jointed at c²,
O to the arm h¹, of a bell-cranked power transmitting lever h, fulcrumed at h²,
to a clip, encircling one of the back stays c, whilst connected to the other
arm, of the said lever by means of a link his the upper end , of a brake
rod, whose lower end ³, is screwed into a fitting & secured to the brake
frame d.
D
,
m is a take-off spring, encircling the rod d³, with its one end m¹, bearing
against the shoulder m³, of a fixed casing m³, secured by a clip m³, to a back
stay c, whilst its lower end abuts against a shoulder d, of the fitting, which
is extended upwards into a sleeve, telescoping and sliding within the cylin-
drical casing m, thus acting as a guide for directing the movement of the brake
frame.
The casing e, of the pressure moderator e, which is constructed and operates
in the same manner as described in connection with the first form of brake, is
adjustably connected to the rod i, by screwing the lower end it, of the latter into
a hole e in the said casing, which is preferably milled at es, to facilitate its
rotation in adjusting the device to suit the distance between the link y and the
lever hand is locked in its determined position by the small nut e.
The means employed in this form of brake for preventing the application of ex-
cessive retarding pressure and also determining the positions which the brake blocks
shall normally assume relative to the wheel rim, consists of a double acting stop k,
arranged to rock upon a cross pin k¹, carried by means of a clip ², on one of
the chain stays. This stop is combined with the brake mechanism in such a
manner as to form the connection or shackle between, and move in common with,
the link y, and the draw bar e², of the moderator e, the end g¹ of the latter. being
connected by means of a screw g, to one side of the forward end of the said stop,
whilst the draw bar is secured to the other side by means of a pin . The forward
and rear ends of the stop are provided respectively with the abutments k¹, k5,
the former of which is adapted to prevent excessive break power being applied
by coming against a part of the framing when the stop is drawn down on the
brake being operated, whilst the latter, by bearing against the top of one of the
chain stays, determines the positions which the several parts shall be returned
o by the expansion of the take-off spring on the break pressure being relieved.
Having now particularly described and ascertained the nature of my said
nvention, and in what manner the same is to be performed, I declare that what
claim is:-
First In back-pedalling cycle brake mechanism provided with spring-
rganized brake pressure moderators, the employment in connection therewith of
stop for preventing the application of excessive brake power.
Secondly-In back-pedalling cycle brake mechanism provided with a spring-
ganized brake pressure moderator and a take-off spring, the employment in
nnection therewith of double stops respectively for preventing the application
excessive brake power and determining the positions to which the several
rts are returned by the expansion of the take-off spring, substantially as herein
scribed and set forth.
Thirdly-In back-pedalling cycle brake mechanism provided with a take-off
ring, the employment in combination with a horse-shoe shaped frame, carried
on the back stays of the machine, of a slide, telescoping and working as a

page_text: guide for the said brake frame within the casing of the said spring whose ends
respectively abut against a shoulder or end of the casing and an opposed shoulder
of the slide, substantially as described and set forth in Figures 7 and 9.
Fourthly: In back-pedalling cycle brake mechanism, the combination with a
system of levers such as h and j, connected by means of a link g and a clutch, to
the driving crank axle, of a brake pressure moderator interposed between the
levers and the brake, and stops k and n, arranged and operating substantially as
and for the purpose as described and set forth in Figures 1, 2 and 3.
9,
Fifthly:- -In back-pedalling cycle brake mechanism, the combination with a
bell cranked power transmission lever such as h, and connecting rods such as
and i, of a brake pressure moderator interposed between the rod i and the link
and a pedal-operated clutch ring, and a double acting rocking stop k, arranged in
connection with the said parts and operating substantially as and for the purpose
herein described and set forth.
DAL
1T1900
OLAF PIHLFELDT,
By Henry Skerrett,
24, Temple Row, Birmingham, Agent for Applicant.