Marine propulsion – Oar or paddle
Reexamination Certificate
2000-03-30
2001-04-03
Avila, Stephen (Department: 3617)
Marine propulsion
Oar or paddle
C416S074000
Reexamination Certificate
active
06210244
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a propulsion apparatus for water sports, and more particularly to a rowing apparatus having a split blade and surface contours and adaptable for use as either an oar or a paddle.
2. Description of the Prior Art
The present invention represents a development from and an improvement on an earlier invention of the same inventor, entitled contoured paddle for water sports, and disclosed in U.S. Utility Patent Application filed Aug. 30, 1999. The prior design comprises, in part, a blade with surface topography for advantageously channeling water over the blade face when in use, and further has a crooked loom for increasing propulsive force. The surface topography comprises fluted channels formed in conjunction with a plurality of gently curving, raised channel ridges. The fluted channels direct water over the sweet spot (or center) of the blade, thereby increasing thrust, and thereafter conduct the water to the blade edges and outwardly in a fashion that evenly distributes water flow, thereby aiding blade stability and propulsion. The primary principle in operation is the Bernoulli effect, which describes local pressure differentials produced by varying velocities of fluid. These pressure differentials are exploited by the contoured paddle to increase efficiency while decreasing the strain on the user.
In certain applications and uses, it would be advantageous to further exploit the principles in effect in the contoured paddle. The present invention represents such an advance.
SUMMARY OF THE INVENTION
According to the present invention, there is provided an improved propulsion apparatus which may be embodied as either an oar or paddle, said oar or paddle being adapted to propel shallow draft watercraft, including kayaks, canoes, racing shells, rafts, skiffs, and the like. The oar or paddle comprises a handle portion, or loom, and at least one split blade, depending upon its use. The split blade comprises at least two working surfaces, preferably only two, having a front and a back blade section, each one of which has topography on its working surface. The topography comprises channel dividers and fluted channels defined thereby for channeling water across the front surfaces of the front and back blade sections of the blade when in use.
As a first preferred embodiment, the present invention may be either a single or double-bladed paddle, suitable, e.g., for canoeing or kayaking, respectively. A second embodiment of the present invention is adapted for use as an oar for rowing shells or white water rafts. In either embodiment, the front and back blade sections may be conjoined to form an opening between the two sections for further advantageous channeling of water.
REFERENCES:
patent: 4832631 (1989-05-01), Gag
patent: 5482434 (1996-01-01), Heaven
patent: 299630 (1992-04-01), None
patent: 4300324 (1994-07-01), None
Avila Stephen
Johnson Larry D.
Johnson & Steinbrook, LLP
Stainbrook Craig M.
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