HUB BRAKE FOR BICYCLES

FREIN A MOYEU POUR BICYCLETTES

English Abstract

A hub brake for bicycles including a cylindrical hub
in which is fitted a screw rod extending therethrough, a
driving device including a driving screw, a bearing, an
adjusting nut, a bearing and an arm, a recovering device
including a torsion spring, a helical spring and a nut,
and a braking device including a brake block and a
positioning plate, and a cover fixedly mounted on the
positioning plate, whereby the hub brake for bicycles can
effectively reduce speed or stopping motion of a bicycle.

Claims

CLAIMS:
1. A hub brake for bicycles comprising:
a cylindrical hub in which is fitted a screw rod
extending therethrough, said hub being formed at an end
with a conical recess;
driving means including a driving screw, a
bearing, an adjusting nut, and an arm, said driving screw
being a tubular member provided with a threaded portion
at a first end and a plurality of notches at a second end,
said arm being formed at an end with an opening having a
plurality of internal teeth and at another end with a hole
adapted to connect with a cable, said arm being connected
to said second end of said driving screw with said
teeth engaged with said notches, said adjusting nut being
fitted within said hole and having a longitudinal internal
threaded hole and a flange at an intermediate portion
thereof, said bearing being fitted over an end of said
adjusting nut and bearing against said flange;
recovering means including a torsion spring, a
helical spring and a nut, said torsion spring being

provided with a hook portion at both ends thereof bearing
against said arm, said helical spring being fitted over said
screw rod and disposed within said conical recess, said
nut being engaged with said screw rod to prevent said
helical spring from detaching from said screw rod;
braking means including a brake block and a
positioning plate, said brake block being slidably mounted
within said positioning plate, said brake block being in the
shape of a frustum shaped cone adapted to be fitted into
said conical recess and having a longitudinal threaded hole
engageable with said threaded portion; and
a cover fixedly mounted on said positioning plate
and having a center hole for passage of said screw rod.

Description

21 92872
TITLE: AN IMPROVED HUB BRAKE FOR BICYC~ES
This invention relates to an improved hub brake for
bicycles.
FIG. 6 illustrates the structure of a prior art hub
brake for bicycles. As shown, the hub brake utilizes a
arm 52 to rotate a rectangular block 53 to drive a pair of
brake shoes 51 thereby expanding a pair of brake shoes 51
to contact the inner surface of the hub and therefore
reducing speed or stopping motion of a bicycle. Further,
two springs 54 are provided for returning the brake shoes
51 to their original positions when the brake is rèleased.
However, such a hub brake suffers from the following
drawbacks:
1. The contact area between the brake shoes 51 and
lS the inner surface of the hub is small thereby making it
impossible to apply brake effectively.
2. Once the brake shoes are worn out and the
rectangular block 53 is not adjusted in time, brake
failure will easily occur.
Therefore, it is an object of the present invention

-- 21 92~72
to provide an improved hub brake which can obviate and
mitigate the above-mentioned drawbacks.
This invention relates to an improved hub brake for
bicycles.
It is the primary object of the present invention to
provide a hub brake for bicycles which can effectively
reduce speed or stopping motion of a bicycle.
It is another object of the present invention to
provide a hub brake for bicycles which can safely keep the
rider from danger.
It is still another object of the present invention
to provide a hub brake for bicycles which can be rapidly
actuated.
It is still another obiect of the present invention
to provide a hub brake for bicycles which is durable in
use.
It is a further obiect of the present invention to
provide a hub brake for bicycles which is easy to
assemble.
Other objects of the invention will in part be

21 q2~72
obvious and in part hereinafter pointed out.
FIG. 1 is an exploded view of the present invention;
FIG. 2 is a perspective view of the present
invention;
FIG. 3 is a sectional view of the present invention;
FIG. 4 is an enlarged fragmentary view of FIG. 4;
FIG. 5 is a working view of the present invention;
and
FIG. 6 illustrates the structure of a prior art drum
brake for bicycles.
For the purpose to promoting an understanding of the
principles of the inven~ion, reference will now be made to
the embodiment illustrated in the drawings. Specific
language will be used to describe same. It will,
nevertheless, be understood that no limitation of the
scope of the invention is thereby intended, such
alternations and further modifications in the illustrated
device, and such further applications of the principles of
the invention as illustrated herein being contemplated as
would normally occur to one skilled in the art to which

21 ~2872
the invention relates.
With reference to the drawings and in particular to
FIGS. 1, 2 and 5, the hub brake for bicycles according to
the present invention mainly comprises a hub 30, a driving
means, a braking means, a recovering means, and a cover
40.
The hub 30 is a cylindrical member in which is fitted
a screw rod 31 extending therethrough. The hub 30 is
formed at an end with a conical recess 301.
The driving means includes a driving screw 21, a
bearing 22, an adjusting nut 23 and an arm 24. The
driving screw 21 is a tubular member provided with a
double-threaded portion 213 at an end and a plurality of
notches 2111 at the other end 211. The arm 24, which
has an opening 241 at an upper end formed with a plurality
of teeth 242 and a hole 243 at a lower end, is connected
to the other end 211 of the driving screw 21 with the
protuberances 242 engaged with the notches 2111.
The hole 243 of the arm 24 is connected with a cable
(not shown). The adjusting nut 23 is fitted within the

21 92872
hole 212 of the driving screw 21 and has a longitudinal
internal threaded hole 231 and a flange at an intermediate
portion. The bearing 22 is fitted over an end of the
adjusting nut 23, bearing against the flange 232 of the
adjustin~ nut 23.
The recovering means includes a torsion spring 25 and
a helical spring 32. The torsion spring 25 is provided
with a hook portion 251 at both ends bearing against the
arm 24. A packing ring 26 is mounted on the screw rod
31 for preventing the torsion spring 25 from disengaging
therefrom. The helical spring 32 is fitted over the-screw
rod 31 and disposed within the conical recess 301 of the
hub 3. A nut 33 is engaged with the screw rod 31 for
preventing the helical spring 32 from detaching from the
screw rod 31.
The braking means includes a brake block 10 and a
positioning plate 14. The brake block 10 is in the shape
of frustrum shaped cone adapted to be fitted into the
conical recess 301 of the hub 3. The brake block 10 has a
longitudinal double-threaded hole 102 engageable with the

21 ~72
double-threaded portion 213 of the driving screw 21 and
three holes 102 around the double threaded hole 102. The
positioning plate 14 is provided with three pins 142 tonly
two of them are shown in FIG. 1) adapted to fit into the
three holes 102 of the brake block 10, an opening 141 for
the passage of the screw rod 31, and four holes 143 around
the opening 141. Hence, the brake block 10 may move with
respect to the positioning plate 14.
The cover 40 is formed with a conical neck 401 at its
central portion and a plurality of holes 403 around the
the conical neck 401. The cover 40 is fixedly mounted on
the positioning plate 14 by screws 60 extending through
the cover 40 into the positioning plate 14, with the screw
rod 31 going through the center hole 402 of the cover 40.
When applying brake, the arm 24 will be pulled by
the cable (not shown) thereby twisting the torsion spring
25 and rotating the driving screw 21. ~owever, as the
driving screw 21 is blocked by the adjusting nut 23 at the
left side (see ~IGS. 1, 2, 3 and 4~, the driving screw 21
will not be moved to the left. In the meantime, the brake

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block 10 will be forced to go into direct contact with the
conical recess 301 of the hub 30 thus reducing speed or
stopping motion of the hub 30. When the brake is
released, the torsion spring 25 will recover to its
original shape hence moving the arm 24 to its original
position and rotating the driving screw 21 in the opposite
direction. Then, the brake block 10 will be moved out of
the conical recess 301 of the hub 30 and no frictional
force will exist thersbetween. Once the brake block 10 is
worn out, it is only necessary to regulate the adjusting
nut 23 to move the brake block 10 slightly toward the
conical recess 301 of the hub 30.
The invention is naturally not limited in any sense
to the particular features specified in the forgoing or to
the details of the particular embodiment which has been
chosen in order to illustrate the invention.
Consideration can be given to all kinds of variants of the
particular embodiment which has been described by way of
example and of its constituent elements without thereby
2~ departing from the scope of the invention. This invention
accordingly includes all the means constitu~ing technical
equivalents of the means described as well as their
combinations.

Representative Drawing