Note: Descriptions are shown in the official language in which they were submitted.
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~ his invention pertains to components for rowing
units which use a braking system that produces a repeatable
resistance allowing the operator's output level to be
measured simply and accurately, and which provides a "feel"
similar to the actual sensation of rowing a boat.
In the prior art rowing units, it is typical -to
provide a friction brake component to provide the resistance
necessary for training. Those components have a number of
inherent disadvantages including the build-up of heat and
wear. Additionally, coefficient of friction fluctuations
result in measurement errors unless the component includes
specific compensation equipment.
Prior devices also use a variety of means to
simulate the sensations of rowing and to provide the resis-
tance necessary to improve performance and endurance. Most
fall short of providing a sensation and resistance similar
to that experienced in actual rowing and which is measurable
and to achieve these goals simply and economically. To
attain these ends, a number of units have recently gone so
far as to complicate the apparatus with electronic cir~uitry.
Having regard to what has been said, it is an aim
of the invention to provide, as a braking component, a fly-
wheel for a stationary rowing unit rotated by rowing action
and which includes an inexpensive, simple means of resis-
tance, which is measurable, reproducible and similar to that
experienced in actual rowing shells and which can be readily
- assembled with other components to provide the complete
unit. It is another aim to provide an effective driving
component which can also be readily assembled, with the
other components of the apparatus, to drive the flywheel.
A flywheel component, according to the invention,
includes a hub and connected outer rim provided with
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weighting means to sustain momentum. The hub is mounted on
a shaft for ro-tation on a frame. Mounted on the flywheel
are b-lades positioned and angled to offer air resistance as
the flywheel is rotated. At least one gear is mounted on
the shaft to mesh with a driving chain and is connected to
a one-way clutch on the shaft. In one form of the invention,
wide spokes constitute blades extending from the hub to the
rim. Desirably there are several gears, of respectively
different sizes, so that the chain can be moved from one
gear to the other to provide different degrees of leverage
and consequently increased or decreased drag to the driving
chain.
In a preferred construction, according to the
invention, the flywheel is essentially a bicycle wheel having
a hub, a weighted rim and spokes extending between them and
as blades a series of separate plates or vanes attached to
the wheel and spaced-apart about its circumference. Each
blade is provided with means at one end engagin~ the rirn
and means at the other engaging a spoke to hold t~le blade
in a position to act as a airfoil resisting rotation of the
wheel.
A preferred form of blade is a plate having an
extensive air-resistant surface extending between first and
second spaced-apart margins. The first margin is provided
with a recess shaped to fit snugly to the bicycle wheel rim.
The second margin is provided with a slot shaped to engage
snugly a spoke, inboard of the rim whereby the plate is held
in position to offer air resistance when the wheel is
rotated. Desirably, the blade is of elongated substantially
rectangular shape. The recess is set to one side of the
longitudinal centerline and the slot slightly to the other
side whereby, when in place, a part of the air-resistant
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surface projects to one side of the rim and spo~e~ o~ the
wheel. The recess may have a wide part for receiving the
inside of the rim and a pair of spaced-apart resilient
projections for engaging the outside of the rim, and the
slot may extend diagonally inward on said second margin
and has an entry part of reduced width having displaceable
sides allowing the entry of the spoke under pressure and
serving to retain the blade in position, once placed. The
plate is best made of plastic material which is flexible
enough to enable deformation for installation but whose
elastic memory is effective to maintain its form when
installed.
The invention will be illustrated in further detail
by reference to the accompanying drawings, which illustrate
preferred embodiments, and in which:
FIG. 1 is a top plan view of a stationary rowing
unit embodying the components of the
invention;
FIG. 2 is a side elevational view thereof;
FIG. 3 is an enlarged side elevational view of
the gearing mechanism of the flywheel unit;
FIG. 4 is a perspective view showing a preferred
flywheel construction, according to the
invention, equipped with specially
designed blades; and
FIG. 5 is a perspective view showing one of the
blades.
In order to illustrate the components of the
invention, the applicants will now describe a stationary
rowing unit equipped with them.
As shown in the figures, the rowing unit is made
up of a frame including an elongated beam 15 spaced from
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the ground by legs. Extending diagonally upwardly and -for-
wardly from one end of the beam are rame members 10 an~ 20
providing a fork. A sliding seat 11 is mounted for sliding
movement back and forth on the beam 15 as a rail. Fixedly
connected to the beam 15 are foot rests 25, 25', with
restraining straps 27 and 27'.
A flywheel 19 is rotatably mounted in the fork
provided by the ends of the frame members 10 and 20 through
a hub and an axle 30. Mounted on the axle 30 and connected
to it by a one-way clutch assembly are respective gears of
difference sizes 29, 29a and 29b. The flywheel 19 is pro-
vided with a weighted rim.
A chain 17, having on one end a handle 16, extends
about one of the gears 29, 29a or 29b and thence under guides
on the frame. The other end of the chain 17 is connected to
an elastic cord 18 whose end is connected to the beam 15.
The flywheel is provided with a number of blades
24, 24a, 24b, etc. which extend inward radially from the
rim to the hub. The blades have an airfoil surface so as
to act as air-resistant vanes when the flywheel is rotated.
A tachometer/revolution counter 26 is mounted on
a post near the flywheel in the line of vision of the
operator.
The operator of the unit 10 sits on the seat 14
putting his feet into the foot rests 25 and 25' and enyag-
ing th~ restraining straps 27 and 27' and heel supports 28
and 28'. The operator grasps the handle 16 and begins the
rowing action.
At rest the elastic cord will pull the chain 17
to the forward position with the handle 16 near the tachometer
post. A pull on the chain 17 in a positive stro~e by the
operator rotates the flywheel through the gear mechanism 22
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and clutch. The blades 24, 24a, 24b, etc. encounter air-
resistance against -the action of the chain. The move~ent
of the chain in the positive stroke also extends the elas-
tic cord. When the operator has reached the end of the
positive stroke, he moves through a return stroke and the
slack on the chain is taken up by the resilience of the
elastic cord returning from its extended position. At the
same time, the momentum of the weighted flywheel, which is
unclutched, it causes it to continue rotating freely. When
the operator reaches the end of the reverse stroke, he pulls
on the chain again in a further positive stroke which engages
the clutch again and he meets resilient resistance again
almost exactly as in the action of rowing a boat in water.
The resistance encountered is different from the frictional
type resistance, of the prior art, which is set at a certain
stable value, because with the braking force caused by air
resistance, this force increases with the speed of the fly-
wheel, so that the resistance encountered increases with the
increased speed of the stroke as in normal rowing.
The tachometer 26 registers the speed of rotation
and also registers the number of rotations.
Fig. 3 is an enlarged side elevational view of the
gearing mechanism 22. This view shows the chain 17 looped
around one gear 29 of a number of gears 29, 29a and 29b on
the sprocket 30, which houses the one-way clutch assembly
23. The chain may be changed from one gear to another to
alter the leverage necessary to accelerate the flywheel 19.
Fig. 4 shows a preferred alternative form of fly-
wheel. This is essentially a bicycle wheel having a rim 41,
a hub 42 and spokes 43. I'he spokes are arranged according
to the so-called "four-across" system as shown. The rim is
weighted with a metal tire so as to retain the momentum of
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the flywheel, once set into motion.
Specially constructed blade members 45 are fitted
to the wheel so that one end engages the rim adjacent a
spoke and the other end engages another spoke inboard from
the rim so that the blades are positioned and angled, as
shown, to offer aerodynamic resistance to the rotation of
the wheel.
Fig. 5 shows a preferred form of blade 45. It is
a thin plate, rectangular in overa]l shape, bordered by side
margins 47 and 49 and end margins 51 and 53. The corners
between the side and end edges are preferably rounded. The
end edge 51 is provided with a recess 55 for fitting over
the rim 41 with a widened part 56 accommodating the curved
inside surface of the rim 41 and a pair of inward projec-
tions 57 engaging the outer face of the rim. The other end
margin 43 is provided with a slot 59 which extends diagonally
inward from the edge. The slot is for engaging a spoke in-
board of the rim 41.
The inward end of the slot is slightly off-centre
of the blade at one side, while the inside of the enlarged
part 56 of the recess 55 is about the centre.
~ith this arrangement, when the blade is mounted
on the wheel, with its recess 55 receiving the rim 41 and
its slot 59 engaging a spoke 43, as shown in the drawings,
part of the blade projects sideways from the rim and the
blade assumes an attitude substantially as illustrated, in
which it offers resistance to air as the wheel is rotated.
As an example, a preferred blade is a plate of
plastic material, about 2 mm thick having a width of about
8 cm, a length of about 15 cm, with the hub recess 55 about
2 cm deep, and the spoke slot about 12 mm deep. The plate
is flexible enough to allow deformation in installing it
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and resilient so that it is substantially rigid, once in
stalled so that the blades maintain their form.
~ preferred flywheel employs 9 blades, but this
can be varied to provide the desired air resistance.
A typical preferred flywheel is a bicycle wheel
having a diameter of about 27 inches with 36 spokes per side.
The weighted tire can be a split metal band of
uniform cross-section fitted to the rim, for example, as a
5/8th by 5/8th bent steel bar having a weight of about 9
pounds.
A specific example of an elastic cord suitable for
the driving apparatus is 3/8th inch white-coated double
nylon black vulcanized rubber shock cord having a length of
about 7 feet in an apparatus of the size exemplified.
The blades 45 are easily assembled onto the wheel.
As the appropriate margin of the blade 45 is pressed against
the inside of the rim 41, the recess 55 readily receives the
rim in a tight fit. The projections 57 flex enough to allow
the blade to be pressed "home", with the edges of the recess
55 snugly engaging the surface of the rim 41 and the resi-
lient memory of the blade material causing projections to
assume their at rest position when engaging under the out-
side surface of the rim. The other end margin is brought
into contact with a spoke inboard of the rim, with the end
of the slot 59 against the spoke. Pressing the blade against
the rim will cause the spoke to enter the slot which is pre-
ferably slightly less than the width of the spoke so that
the material of the bla~e is deformed enough to allow the
spoke to enter and ultimately the material hugs the spoke
30 so as to hold the blade in place. It will be clear that
the resilience of the blade material will allow the blade to
be readily removed.
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