Note: Descriptions are shown in the official language in which they were submitted.
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BICYCLE PEDAL STRUCTURE CAPABLE OF TRIGGERING AUXILIARY POWER
FIELD OF THE INVENTION
The present invention relates to bicycle pedal structures capable of
triggering auxiliary power
and more particularly to a bicycle pedal structure which is capable of
triggering auxiliary power and
mounted on a bicycle chassis to supply auxiliary power to an electric bicycle
and thus drive the
electric bicycle to move.
BACKGROUND OF THE INVENTION
A conventional bicycle essentially comprises a pedal structure, a gear train
coupled to a wheel
axis, and a chain connected between the pedal structure and the gear train. In
general, the pedal
structure has a crank shaft, a gear coupled to the crank shaft, and pedal
cranks disposed at the two
ends of the crank shaft, respectively, such that a cyclist treads on the
pedals connected to the pedal
cranks to thereby rotate the crank shaft, thus allowing the chain to drive the
wheels of the bicycle to
rotate.
To render cycling less laborious, the prior art discloses a bicycle which
comprises a driving
motor and a controller thereof so as for the driving motor to supply auxiliary
power required for the
rotation of a crank shaft coupled to a bicycle pedal structure. In this
regard, a sensor is mounted on the
crank shaft coupled to the bicycle pedal structure to thereby detect the
rotation speed and torque of the
crank shaft, so as to determine whether the controller is operating and
determine whether to adjust the
operating status of the driving motor.
Since the sensor is mounted on the crank shaft, it not only rotates together
with the crank shaft
but also transmits an electrical signal by coming into contact with a
collector ring. As a result, the
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sensor is predisposed to poor contact with a collector ring and thus unstable
transmission of the
electrical signal. In addition, the overall structure is not only intricate
but also vulnerable.
SUMMARY OF THE INVENTION
It is an objective of the present invention to provide a bicycle pedal
structure which is capable of
triggering auxiliary power, structurally simple, and operating with the least
possible parts and
components.
In order to achieve the above and other objectives, the present invention
provides a bicycle pedal
structure capable of triggering auxiliary power. The bicycle pedal structure
is mounted on a bicycle
chassis and connected to a driving-controlling system. The bicycle pedal
structure comprises a base, a
sleeve unit, a crank shaft, two pedal cranks and a treading force sensing
unit. The base has a first
opening and a second opening. The sleeve unit is disposed in the base and has
a first sleeve and a
second sleeve. The first sleeve is disposed in the first opening. The second
sleeve is disposed in the
second opening. The crank shaft is fitted in the first sleeve and the second
sleeve and rotatably
disposed in the base. The two pedal cranks are coupled to two ends of the
crank shaft, respectively,
extending in opposite directions, being substantially perpendicular to the
crank shaft, and having a
pedal each for rotating the crank shaft under a treading force. The treading
force sensing unit has a
plurality of piezoelectric plates. The piezoelectric plates are disposed on at
least the first sleeve and
the second sleeve and above the crank shaft.
As regards the bicycle pedal structure, the treading force sensing unit has
four piezoelectric
plates. The piezoelectric plates are disposed on the first sleeve and the
second sleeve, above and
below the crank shaft, respectively.
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As regards the bicycle pedal structure, the first sleeve and the second sleeve
each have a bearing
for supporting the crank shaft.
The bicycle pedal structure further comprises a rotation speed sensor disposed
on the first sleeve
and spaced apart from the piezoelectric plates.
As regards the bicycle pedal structure, the first sleeve and the second sleeve
each have a flange
whereby the bicycle pedal structure is fixed to the base.
As regards the bicycle pedal structure, the treading force sensing unit is
disposed on a sleeve unit
which does not rotate such that the treading force sensing unit does not
rotate along with the crank
shaft while the cyclist is riding the bicycle. Therefore, the bicycle pedal
structure is not only simple in
terms of its circuit, parts and components but also invulnerable.
BRIEF DESCRIPTION OF THE DRAWINGS
Objectives, features, and advantages of the present invention are hereunder
illustrated with
specific embodiments in conjunction with the accompanying drawings, in which:
FIG. 1 is a perspective view of a bicycle pedal structure according to an
embodiment of the
present invention;
FIG. 2 is a cross-sectional view of the bicycle pedal structure according to
the embodiment of
the present invention;
FIG. 3 is another perspective view of the bicycle pedal structure according to
the embodiment of
the present invention;
FIG. 4 is another perspective view of the bicycle pedal structure taken at
another angle according
to the embodiment of the present invention; and
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FIG. 5 is a schematic view of the operation of a crank shaft according to the
embodiment of the
present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In an embodiment of the present invention, a bicycle pedal structure 1 capable
of triggering
auxiliary power is mounted on a bicycle chassis (not shown) and connected to a
driving-controlling
system (not shown). The driving-controlling system comprises a controller and
a driving motor. The
controller controls the strength of the output torque generated from the
auxiliary power supplied by
the driving motor. As soon as the driving-controlling system detects that a
cyclist is treading, the
controller is triggered to either start the driving motor or change the output
torque of the driving
motor so as to provide digital modularized auxiliary power to the bicycle
pedal structure 1, thereby
supplementing or replacing the power required for the forward motion of the
bicycle.
Referring to FIG. 1 and FIG. 2, in an embodiment of the present invention, the
bicycle pedal
structure 1 comprises a base 10, a single-sided sleeve 20, a crank shaft 30,
two pedal cranks 40 and a
treading force sensing unit 50. The base 10 has a first opening 11 and a
second opening 12. The sleeve
unit 20 is disposed in the base 10 and has a first sleeve 21 and a second
sleeve 22. The first sleeve 21
is disposed in the first opening 11. The second sleeve 22 is disposed in the
second opening 12. The
crank shaft 30 is fitted in the first sleeve 21 and the second sleeve 22 and
thus rotatably disposed in
the base 10. The two pedal cranks 40 are coupled to the two ends of the crank
shaft 30, respectively.
The two pedal cranks 40 extend in opposite directions and are substantially
perpendicular to the crank
shaft 30. The pedal cranks 40 each have a pedal 41. The treading forces
generated from the cyclist's
left and right feet are exerted on the pedals 41, respectively, to rotate the
crank shaft 30. The treading
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force sensing unit 50 has a plurality of piezoelectric plates 51a. The
piezoelectric plates 51a are
disposed on at least the first sleeve 21 and the second sleeve 22 and above
the crank shaft 30.
Referring to FIG. 1, the base 10 is provided in the form of a casing which has
therein a receiving
space. The first opening 11 and the second opening 12 are opposite to each
other and flank the
bicycle. The base 10 further has a third opening 13 whereby the base 10 is
mounted on the bicycle
chassis.
Referring to FIG. 2, the sleeve unit 20 is disposed in the base 10. The first
sleeve 21 is disposed
in the first opening 11. The second sleeve 22 is disposed in the second
opening 12. The first sleeve 21
and the second sleeve 22 are fitted at the two ends of the crank shaft 30,
respectively. The first sleeve
21 has therein a bearing 23. The second bearing 22 has therein a bearing 24.
The bearings 23, 24
support the crank shaft 30 in a manner to allow the crank shaft 30 to be
rotatably disposed in the base
10.
In this embodiment, the treading force sensing unit 50 has at least two
piezoelectric plates 51a.
The piezoelectric plates 51a are disposed on at least the first sleeve 21 and
the second sleeve 22 and
above the crank shaft 30. Referring to FIG. 3 and FIG. 4, the treading force
sensing unit 50 has four
piezoelectric plates 51a, 51b. The piezoelectric plates 51a, 51b are disposed
on at least the first sleeve
21 and the second sleeve 22, respectively, and are positioned above and below
the crank shaft 30,
respectively. Hence, when a bicycle with the bicycle pedal structure 1 is
advancing, the piezoelectric
plates 51a disposed on the first sleeve 21 and the second sleeve 22 are
farthest from the ground,
whereas the piezoelectric plates 51b disposed on the first sleeve 21 and the
second sleeve 22 are
closest to the ground. Referring to FIG. 3 and FIG. 4, a flange 25, 26 is
disposed at the end of each of
the first sleeve 21 and the second sleeve 22. The edges of the flange 25, 26
are engaged with the base
from inside to thereby allow the first sleeve 21 and the second sleeve 22 to
be fixed to the base 10.
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The bicycle pedal structure 1 has a rotation speed sensor 60. The rotation
speed sensor 60 is
disposed on the first sleeve 21 and spaced apart from the piezoelectric plates
51a, 51b. For example,
an included angle of 90 degrees is formed between the line which joins the
rotation speed sensor 60 to
the center of the crank shaft 30 and the line which joins the piezoelectric
plates 51a or the
piezoelectric plates 51b to the center of the crank shaft 30. The purpose of
the rotation speed sensor
60 is to measure the rotation speed of the crank shaft 30. The rotation speed
sensor 60 is exemplified
by a Hall sensing component.
Referring to FIG. 5, in this embodiment, when the cyclist treads on the pedals
41 and thus exerts
a downward treading force thereon to thereby enable the pedal cranks 40 to
rotate the crank shaft 30;
meanwhile, the downward treading force is conveyed to the crank shaft 30
through the pedal cranks
40 so as to not only bend the crank shaft 30 slightly but also deform the
first sleeve 21. Hence, the
piezoelectric plates 51a, 51b above and below the crank shaft 30 deform,
undergo voltage changes,
and eventually send an electrical signal to the driving-controlling system.
The electrical signal thus
sent triggers the driving-controlling system to generate digit modularized
auxiliary power. The
auxiliary power drives the crank shaft 30 to rotate; hence, it is less
laborious for the cyclist to produce
the treading force than without the bicycle pedal structure 1 of the present
invention.
According to the embodiment of the present invention, the bicycle pedal
structure 1 is
characterized in that the treading force sensing unit 50 is disposed on the
sleeve unit 20 which does
not rotate such that the treading force sensing unit 50 does not rotate along
with the crank shaft 30
while the cyclist is riding the bicycle. Therefore, the bicycle pedal
structure 1 is not only simple in
terms of its circuit, parts and components but also invulnerable.
The present invention is disclosed above by preferred embodiments. However,
persons skilled in
the art should understand that the preferred embodiments are illustrative of
the present invention only,
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but should not be interpreted as restrictive of the scope of the present
invention. Hence, all equivalent
modifications and replacements made to the aforesaid embodiments should fall
within the scope of
the present invention. Accordingly, the legal protection for the present
invention should be defined by
the appended claims.
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