Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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PEDAL MECHANISM FOR STATIONARY EXERCISING BICYCLE
HAVING INDEPENDENT LEFT AND RIGHT CRANKS
BACKGROUND OF THE INVENTION
Field of the invention:
The present invention relates to a pedal
mechanism for stationary exercising bicycle, in which
the left and right cranks are individually and
pivotally connected to the bicycle about a common
axis.
2. Brief description of the prior art:
To present a good performance during
competitions, the legs of a cyclist must apply a
steady force on the pedals in the four sectors of
pedalling, that is over 360 during each revolution of
the pedal.
The four sectors of pedalling comprise:
(a) a first power sector in which the
pedal is lowered by extending the thigh and then the
leg to apply a downward force on that pedal;
(b) a second sector, said lower dead
point, in which the pedal, in the lower position, is
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moved rearwardly by extending the foot and then the
leg;
(c~ a third sector in which the pedal is
lifted through a flexion of the thigh and then of the
leg; and
(d) a fourth sector, said upper dead
point, in which the pedal, in its upper position, is
moved forwardly by extending the leg and then the
foot, before being lowered again (first sector).
Obviously, this cycle is repeated during
each revolution of the pedal.
During a competition, many cyclists apply
efficiently a force on the pedal only in the first
sector. Under these conditions, the three other
sectors are not exploited efficiently and the
performance of these cyclists is thereby reduced.
OBJECT OF THE INVENTION
An object of the present invention is
therefore to provide a pedal mechanism for a
stationary exercising apparatus, for example of the
bicycle type, that forces the cyclist to apply an
steady and therefore efficient force on the pedal in
the four sectors of pedalling, and that during each
revolution.
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SUMMARY OF THE INVENTION
In accordance with the present invention,
there is provided a pedal mechanism for stationary
exercising apparatus, comprising (a) first and second
pivotal connections mounted on the apparatus, (b) left
and right cranks having respective first ends mounted
on the first and second pivotal conn~ctions,
respectively, to rotate independently about a common
axis, each of these left and right cranks comprising
a second end remote from the common axis, (c) a left
pedal mounted rotatable on the second end of the left
crank about a second axis parallel to the common axis,
this left pedal comprising means for attaching the
left foot of a user person thereto, (d) a right pedal
mounted rotatable on the second end of the right crank
about a third axis parallel to the common a~is, the
right pedal comprising means for attaching the right
foot of the user person thereto, and ~e) means for
resisting to rotational movement of the left and right
cranks about the common axis.
Therefore, as resistance to rotational
movement of the left and right cranks is applied and
as these two cranks rotate independently about the
common axis, a user person must, in order to rotate
any of the left and right cranks at constant speed
about the common axis, apply a steady force on the
corresponding left or right pedal over 360 for each
revolution, that is in the four sectors of pedalling.
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In accordance with preferred embodiments
of the present invention, the first pivotal connection
comprises a left cylinder mounted rotatable on a shaft
section about the longitudinal axis of this shaft
section, the second pivotal connection comprises a
right cylinder mounted rotatable on the shaft section
about the longitudinal axis, the first end of the left
crank is mounted on the left rotatable cylinder, the
first end of the right crank is mounted on the right
rotatable cylinder, the left cylinder is rotatively
mounted in a first cylindrical bushing itself mounted
on the exercising apparatus, and the right cylinder is
rotatively mounted in a second cylindrical bushing
itself mounted on the exercising apparatus.
In accordance with other preferred
embodiments of the pedal mechanism:
a left flywheel is mounted on the left
cylinder to rotate with this left cylinder about the
longitudinal axis, this left flywheel comprising a
peripheral, circular edge surface;
a first friction band attached to the
exercising apparatus and on which the edge surface of
the left flywheel slides upon rotation thereof;
means for tensioning this first friction
band;
a right flywheel mounted on the right
cylinder to rotate with the right cylinder about the
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longitudinal axis, this right flywheel comprising a
peripheral, circular edge surface;
a second friction band attached to the
exercising apparatus and on which the edge surface of
the right flywheel slides upon rotation thereof; and
means for tensioning the second friction
band.
Furthermore, the pedal mechanism may
comprise means for interconnecting the left and right
flywheels whereby the pedal mechanism can be operated
as a conventional pedal and gear mechanism.
The objects, advantages and other features
of the present invention will become more apparent
upon reading of the following non restrictive
description of a preferred embodiment thereof, given
by way of example only with reference to the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the appended drawings:
Figure 1 is a side elevational view of a
stationary exercising bicycle comprising a pedal
mechanism in accordance with the present invention;
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Figure 2 is a perspective view of the
pedal mechanism of the exercising bicycle of Figure l;
Figure 3 is an elevational, cross
sectional front view of the pedal mechanism of Figure
2;
Figure 4 is an elevational, cross
sectional view of the pedal mechanism of Figure 2,
taken along line 4 - 4 of Figure 3;
Figure 5 is an elevational, cross
sectional view of the pedal mechanism of Figure 2,
taken along line 5 - 5 of Figure 3; and
Figure 6 is an elevational, cross
sectional view of the pedal mechanism of Figure 2,
taken along line 6 - 6 of Figure 3.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Figure 1 of the appended drawings
illustrates a stationary exercising bicycle 10
comprising a pedal mechanism 27 (Figure 2) in
accordance with the present invention.
The bicycle 10 comprises a metallic frame
14 provided with a head tube 15. A metallic fork 12
includes a stem 16 pivotally mounted in the head tube
15. On the upper end of the stem 16 are mounted
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handlebars 13. A front wheel 11 is conventionally,
rotatively installed on the free end of the fork 12.
The frame 14 further comprises a crossbar
17, a down tube 18, a seat tube 19, a pair of seat
stays 20, and a pair of chain stays 21.
A seat 24 is mounted on the upper free end
of a seat post 25 itself mounted in the seat tube 19
and fixed in the desired position by means of a
conventional collar 26.
Two plates 22, located at the intersection
of the seat 20 and chain 21 stays on the left and
right sides of the bicycle 10 where the rear wheel
(not shown) is normally mounted, are secured to a
massive, stable and stationary support ~3, of suitable
design. As can be appreciated, the support 23 renders
the exercising bicycle 10 stationary.
As better shown in Figure 2, the seat tube
19, in the region of the pedal mechanism 27, separates
into a pair of left 19' and right 19'' tubes. The
tubes 191 and 19 " are divergent but comprises end
sections 190 and 191 parallel to each other. The
lower, free end of the tube 19' is welded to a left
cylindrical sleeve 28 (Figure 3) while the lower, free
end of the tube 19'' is welded (Figure 5) to a right
cylindrical sleeve 29. The sleeves 28 and 29 are
centered on the same transversal axis 40 (Figure 3).
The down tube 18 also separates, in the
region of the pedal mechanism 27, into left 18' and
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right 18'' tubes (Figure 2). These tubes 18' and 18''
are divergent but comprise end sections 180 and 181
parallel to each other. Again the lower, free ends of
the tubes 18' and 18'' are welded to the left and
right sleeves 28 and 29, respectively (Figures 2 and
5).
As also illustrated in Figures 2 and 5,
the front ends of the chain strays 21 are welded to
the left and right cylindrical sleeves 28 and 29,
respectively.
As will become apparent upon reading of
the following description, this construction will
provide for adequate spacing between the sleeves 28
and 29, between the down tubes 18' and 18'', between
the seat tubes 19' and 19 ", and between the chain
stays 21 to install the pedal mechanism 27.
The pedal mechanism 27 will now be
described with reference. to Figures 1 - 6 of the
appended drawings.
The pedal mechanism 27 comprises a
cylindrical bushiny 30 snugly fitted into the right
sleeve 29. The sleeve 29 and the bushing 30 are both
centered on the transversal axis 40 (Figure 3), and
the length of the bushing 30 is equal to that of the
sleeve 29. The inner cylindrical surface of the
bushing 30 is formed with a flange 36 at the proximate
end of that bushing.
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A cylinder 32 is mounted rotatable on the
inner surface of the bushing 30 through needle bearing
33, resting on the flange 36.
The cylinder 32 (Figures 3 and 6)
comprises a proximate end 34 of reduced outer diameter
on which the central cylindrical hole of a right
flywheel 35 snugly fits. The flywheel 35 is formed on
the side of the sleeve 29 with an annular cavity 37
defining a tube section 38 around the central hole o~
the flywheel. A threaded hole is formed through the
tube section 38 in order to lock the flywheel 35 on
the proximate end 34 by means of a screw 39. ~s can
be seen, the cavity 37 creates a passage that enables
tightening of the screw 39. Of course, the flywheel
35 will rotate with the cylinder 32 about the axis 40.
On the distal end of the cylinder 32 is
formed an outer shoulder 41. Therefore, after the
cylinder 32 and needle bearing 33 have been inserted
into the bushing 30 from the right side of the bicycle
and the flywheel 35 has been locked onto the
proximate end 34 by means of the screw 39, the
shoulder 41 and the tube section 38 will rest on the
respective ends of the bushing 30 to retain the
cylinder 32 in the position illustrated in Figure 3.
The inner surface of the cylinder 32 is
formed with a generally central, annular and
rectangular cavity 42 (Figure 3). The distal end of
the cylinder 32 is also formed with an inner annular
shoulder 43.
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A central shaft section 44, having a
longitudinal axis corresponding to the axis 40, is
mounted in the cylinder 32 through needle bearing ~5
received into the annular cavity 42. The cylinder 32
is ther~fore rotatable on the shaft section 44. The
right end of the shaft section 44 is formed with an
axial threaded hole (not shown) in which a bolt 59 is
screwed. The bolt 59 is associated with a washer 46
of which one face rests on the shoulder 43 to thereby
prevent longitudinal movement of the shaft section 44
toward the left.
The distal annular end surface 47 (Figure
4) of the cylinder 32 is formed with aligned and
diametrically opposed V-shaped groove portions 48 and
49. The end surface 47 is also provided with a pair
of diametrically opposed threaded holes 50 and 51, 90
apart from the groove portions 48 and 49.
The right crank 52 of the bicycle 10 has
a circular end provided with a pair of diametrically
opposed holes 53 and 54 and with a straight triangular
tongue 55 on the inner face thereof. The crank 52 is
mounted on the distal end of the cylinder 32 by
inserting the triangular groove 55 in the V-shaped
groove portions 48 and 49 and by tightening a screw
5Ç, passing through the hole 53, in the threaded hole
50, and by tightening a screw 57, passing through the
hole 54, in the threaded hole 51.
Upon operation of the crank 52 through the
pedal 58 (Figure 1) rotatively mounted on the free end
of the crank 52 about an axis parallel to the axis 40,
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the cylinder 32 along with the flywheel 35 will rotate
about the transversal axis 40, as this cylinder can
rotate on the inner surface of the bushing 30 through
the needle bearing 33 and on the outer surface of the
shaft section 44 through the needle bearing 45.
The flywheel 35 comprises a peripheral
circular edga surface 60 on which a flexible friction
band 61 is placed. The two ends of this band 61 are
attached to a conventional device 62 capable of
tensioning the band and thereby produce a resistance,
by friction, to rotational movement of the flywheel
35, an therefore of the cylinder 32 and crank 52.
$5 As can be appreciated, operation of the
right pedal 58 and crank 52 is independent from
operation of the corresponding left pedal and crank.
The pedal mechanism 27 further comprises
a cylindrical bushing 31 snugly fitting into the left
sleeve 28. The sleeve 28 and the bushing 31 are both
centered on the transversal axis 40 (Figure 3), and
the length of the bushing 31 is equal to that of the
sleeve 28. The inner cylindrical surface of the
bushing 31 is formed with a flange 63 at the proximate
end of that bushing.
A cylinder 64 is mounted rotatable on the
inner surface of the bushing 31 through needle bearing
65, resting on the flange 63.
The cylinder 64 (Figure 3) comprises a
proximate end 66 of reduced outer diameter on which
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the central cylindrical hole of a left flywheel 67
snugly fits. The flywheel 67 is formed on the side of
the sleeve 28 with an annular cavity 68 defining a
tube section 69 around the central hole of the
flywheel 67. A threaded hole is formed through the
tube section 69 in order to lock the flywheel 67 on
th~ proximate end 69 by means of a screw 70. As can
be seen, the cavity 68 creates a passage that enables
tightening of the screw 70. Of course, the flywheel
67 will rotate with the cylinder 64 about the axis 40.
On the distal end of the cylinder 64 is
formed an outer shoulder 71. Therefore, after the
cylinder 64 and needle bearing 65 have been inserted
into the bushing 31 from the left side of the bicycle
10 and the flywheel 67 has been locked onto the
proximate end 66 by means of the screw 70, the
shoulder 71 and the tube section 69 will rest on the
respective ends of the bushing 31 to retain the
cylinder 64 in the position illustrated in Figure 3.
The inner surface of the cylinder 64 is
formed with a generally central, annular and
rectangular cavity 72 (Figure 3). The distal end of
the cylinder 64 is also formed with an inner shoulder
73.
The central shaft section 44 is also
mounted in the cylinder 64 through needle bearing 74
received into the annular cavity 72, whereby the
cylinder 64 is also rotatable onto the shaft section
44. A bolt 75 is screwed into an axial threaded hole
(not shown) provided at the left end of the shaft
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section. The bolt 75 is associated with a washer 76
of which one face rests on the shoulder 73 to prevent
longitudinal movement of the shaft section 44 toward
the right. Accordingly/ the bolts 59 and 75 along
with the washers 46 and 76 maintain the shaft section
44 in the position shown in Figure 3.
The distal annular end surface 77 (Figure
3) of the cylinder 64 is formed with aligned and
diametrically opposed V-shaped groove portions (see 48
and 49 in Figure 4 for the cylinder 32). The end
surface 77 is also provided with a pair of
diametrically opposed threaded holes 78 and 79, 90
apart from the groove portions in the surface 77.
The right crank 80 of the bicycle lO has
a circular end provided with a pair of diametrically
opposed holes 81 and 82 and with a straight triangular
tongue 83 on the inner face thereof. The crank 80 is
mounted on the distal end of the cylinder 6~ by
inserting the triangular tongue 83 in the V-shaped
groove portions of surface 77 and by tightening a
screw 84, passing through the hole 81, in the threaded
hole 78, and by tightening a screw 85, passing through
the hole 82, in the threaded hole 79.
Upon operation of the crank 80 through the
left pedal 86 (Figure 1) rotatively mounted on the
free end of the crank 80 about an axis parallel to the
axis 40, the cylinder 64 along with the flywheel 67
will rotate about the transversal axis 40, as this
cylinder 64 can rotate on the inner surface of the
bushing 31 through the needle bearing 74 and on the
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14
outer surface of the shaft section 44 through the
needle bearing 65.
The flywheel 80 comprises a peripheral
circular edge surface 87 on which a flexible friction
band 88 is placed. The two ends of this band 88 are
attached to the conventional device 62 capable of
tensioning the band 88 and thereby produce a
resistance, by friction, to rotational movement of the
flywheel 67, and therefore of the cylinder 64 and
crank 80.
As can be appreciate, operation of the
right pedal 86 and crank 80 is independent from
operation of the corresponding left pedal 58 and crank
52.
With a pedal mechanism 27, rotation of
one pedal will not cause rotation of the other pedal.
In particular, lowering of one pedal will not cause
lifting of the other pedal. The cyclist will
therefore have to apply separate forces to each pedal.
As resistance to rotational movement of the left 80
and right 52 cranks is produced by the friction bands
61 and 88, and as these two cranks 52 and 80 are
capable of rotating independently about the axis 40,
a cyclist must, in order to rotate any of the left 80
and right 52 cranks at constant speed about the common
axis 40, apply a steady force on the corresponding
left 86 or right 58 pedal over 360~ for each
revolution, that is in the four sectors of pedalling
(see for example the arrows 94 - 97 in Figures 1 and
2). This will force the cyclist to practice the
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correct movements to apply a steady force in the four
sectors of pedalling, to thereby improve his
performance during competitions. Obviously, it is
important to provide the pedals 58 and 86 with
mechanisms capable of attaching the shoes of the
cyclist to these pedals. These mechanisms are
schematically illustrated in Figure 1 by grooves 92
and 93 for the pedals 58 and 86, respectively.
As illustrated in Figure 3, aligned holes
89 and 90 can be drilled through the flywheels 35 and
67, respectively. Hole 89 is threaded and hole 90 is
of larger diameter to receive a shoulder bolt 91 that
will lock the two flywheel 35 and 67 together with the
cranks 52 and 80 diametrically opposed. This will
enable, if desired, normal operation of the exercising
bicycle.
Although the present invention has been
described hereinabove by way of a preferred embodiment
thereof, this embodiment can be modified at will,
within the scope of the appended claims, without
departing from the spirit and nature of the present
invention.
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