U.S. patent application number 11/201633 was filed with the patent office on 2006-05-18 for injection molded paddle blade.
This patent application is currently assigned to Confluence Watersports Company. Invention is credited to Peter W. Jones.
Application Number | 20060105649 11/201633 |
Document ID | / |
Family ID | 35908181 |
Filed Date | 2006-05-18 |
United States Patent
Application |
20060105649 |
Kind Code |
A1 |
Jones; Peter W. |
May 18, 2006 |
Injection molded paddle blade
Abstract
A paddle blade for use in watersports is provided. The paddle
blade includes: a shaft interface portion; a stiffening spine; and
a blade portion including a fan-shaped tapered portion, a tip
region and blade edges; wherein a hollow region is defined in the
blade portion extending through the fan-shaped tapered portion
toward the tip region but short of the blade edges.
Inventors: |
Jones; Peter W.; (Portland,
OR) |
Correspondence
Address: |
KOLISCH HARTWELL, P.C.
200 PACIFIC BUILDING
520 SW YAMHILL STREET
PORTLAND
OR
97204
US
|
Assignee: |
Confluence Watersports
Company
|
Family ID: |
35908181 |
Appl. No.: |
11/201633 |
Filed: |
August 10, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60600828 |
Aug 10, 2004 |
|
|
|
Current U.S.
Class: |
441/56 |
Current CPC
Class: |
B63H 16/04 20130101 |
Class at
Publication: |
441/056 |
International
Class: |
A63B 31/10 20060101
A63B031/10 |
Claims
1. A paddle blade for use in watersports comprising: a shaft
interface portion; a stiffening spine; and a blade portion
including a fan-shaped tapered portion, a tip region and blade
edges; wherein a hollow region is defined in the blade portion
extending through the fan-shaped tapered portion toward the tip
region but short of the blade edges.
2. The paddle blade of claim 1 wherein the hollow region extends
into the stiffening spine.
3. The paddle blade of claim 1 wherein the hollow region extends
into the tip region.
4. The paddle blade of claim 2 wherein the hollow region extends
into the tip region.
5. The paddle blade of claim 2 wherein the hollow region is
symmetrical within the blade portion and stiffening spine.
6. A paddle for use in water sports comprising: a paddle handle; a
paddle shaft; a shaft interface portion; a stiffening spine; and a
blade portion including a fan-shaped tapering portion and blade
edges; wherein a hollow region is defined in the stiffening spine
and the blade portion extending through the fan-shaped tapered
portion toward but short of the blade edges.
7. The paddle of claim 6 wherein the hollow region extends into
close proximity of the blade edges.
8. The paddle of claim 6 wherein the hollow region extends to
within three-quarters of an inch of the blade edges.
9. The paddle of claim 8 wherein the hollow region extends to
within half an inch of the blade edges.
Description
[0001] This application claims the benefit of U.S. provisional
patent application No. 60/600,828 filed Aug. 10, 2004 entitled
Injection Molded Paddle Blade, which is hereby incorporated by
reference in its entirety for all purposes.
TECHNICAL FIELD
[0002] The present disclosure relates to a paddle blade for a
self-propelled watercraft molded by a gas-assisted injection
molding process.
SUMMARY
[0003] A paddle blade for use in watersports is provided. The
paddle blade includes: a shaft interface portion; a stiffening
spine; and a blade portion including a fan-shaped tapered portion,
a tip region and blade edges; wherein a hollow region is defined in
the blade portion extending through the fan-shaped tapered portion
toward the tip region but short of the blade edges.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a view of the underside of a first embodiment of a
gas assisted injection molded blade for a paddle, showing the
hollow region.
[0005] FIG. 2 is a side elevation view of the embodiment of FIG.
1.
[0006] FIG. 3 is a plan view of the upper side of the embodiment of
FIG. 1.
[0007] FIG. 4 is a view of the underside of a second embodiment of
a gas assisted injection molded blade for a paddle.
[0008] FIG. 5 is a side elevation view of the embodiment of FIG.
4.
[0009] FIG. 6 is a plan view of the upper side of the embodiment of
FIG. 4.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0010] The present disclosure relates to a novel blade for a paddle
for a self-propelled personal watercraft such as a kayak, and a
novel paddle having at least one blade. Generally, gas assisted
injection molding is used to form a paddle blade (shown at 10 in
FIGS. 1-3) having improved buoyancy, stiffness, anti-cavitation
characteristics, and other performance features compared to prior
paddle blades. In particular, in some embodiments, gas assisted
injection molding is used to form a paddle blade with a unique
combination of a stiffening spine formed along a first portion of
the blade, shown at 12 in FIGS. 1-3, and a fan-shaped
extension/taper of the stiffening spine, shown generally at 14,
along the remainder of paddle blade 10. Fan-shaped extension/taper
14 allows an area of paddle 10 to include a hollow region 16 with
improved buoyancy. Furthermore, fan-shaped extension/taper 14 of
stiffening spine 12 acts as a double airfoil, providing lift to aid
in the removal of paddle blade 10 from the water and during a
paddle stroke.
[0011] Careful control of the temperature zones of the injection
mold during the injection molding process allows the hollow region
to be formed. The outer area of the mold, near a tip region 18 of
blade 10, is maintained at a higher temperature than a shaft
interface 20 (i.e. where the paddle shaft meets the blade) of the
mold so that resin at the tip region of the mold remains at a low
enough viscosity for the gas injected into the mold to form a gas
bubble near the tip region of the mold. The nominal wall thickness
of the paddle (i.e. the thickness between the hollow interior and
the exterior) in some embodiments is approximately 1/8 inch, but
may be either greater or lesser than this. Furthermore, the walls
may be thinner in the tip region 18 of paddle 10 than in other
regions.
[0012] Paddle blade 10 also is lighter weight than known gas
assisted injection molded paddles due to the hollow tip and spine
structure. For example, paddle blade 10 has a mass of approximately
300 grams, whereas another gas assisted injection molded paddle
blade of a substantially similar size having a solid tip and
different stiffening structure than stiffening spine 12 was found
to have a mass of approximately 370 grams. Furthermore, paddle
blade 10 was found to have a buoyancy of 49 grams, centered about
tip region 18, whereas the other blade was found to have a buoyancy
of only 11 grams, centered about its shaft interface. Therefore,
paddle blade 10 offers superior buoyancy at its tip, thereby
offering superior assistance in removing the paddle blade from the
water at the end of a stroke.
[0013] As shown in FIG. 1, stiffening spine 12 is appears on the
back face of the paddle, and in the depicted embodiment extends
approximately 2/3 the full length of paddle 10. Hollow spine 12
provides a channel for material and gas flow from shaft interface
20 to tip region 18, and is the primary structure for paddle
rigidity, and retention of form. Tip region 18, representing
approximately 1/3 of the full length in the depicted embodiment,
fans out to meet the blade edges. This results in the unique visual
form, provides stiffness to the tip region of paddle 10 and
additional structural support to the blade edges. It also results
in a hollow region that extends symmetrically through the
blade.
[0014] The fanned profile of tip region 18 has a section profile
described as two opposing airfoils. These airfoils provide lift to
the paddle during the paddle stroke, increasing paddle efficiency
and reducing user strain. It also provides lift to the paddle as it
exits the water, reducing the energy required for the user raise
the blade at the end of paddle stroke. This airfoil and lift
minimizes splash during entry and exit of paddle into water,
reducing incidental wetness of the user. It also provides low
resistance of the paddle during entry and exit modes of the paddle
stroke, thereby reducing user strain.
[0015] The fact that the hollow region 16 extends through
stiffening spine 12 and toward tip region 18 results in a paddle
blade that is positively buoyant. Buoyancy is centered about tip
region 18, which is where buoyancy has the greatest effect on
paddle performance. Buoyancy provides upward momentum to the paddle
as it exits the water, reducing the energy required for the user to
raise the blade at the end of the paddle stroke. Buoyancy
counteracts the overall weight of the paddle in use, reducing user
strain.
[0016] Paddle blade 10 represents an ideal relationship of size and
length of the hollow spine, and fan shaped tip, providing a
continuous structure for the full length of the paddle blade for
retention of form, rigidity in use, and durability. It also results
in minimal material usage and overall paddle weight, matching or
less than existing designs, while providing the additional
maximization of positive buoyancy. Moreover, this design provides
minimum cavitation of water throughout the entire stroke.
Cavitation severely reduces efficiency during the paddle stroke.
Cavitation may be induced in normal use by the articulation of the
spine, which in this design is most severe at the shaft and
blending into the relatively flat, fan shaped tip profile that has
no relative articulation.
[0017] In the embodiment of FIGS. 1-3, stiffening spine 12 and fan
shaped extension/taper 14 are generously blended into the blade
faces and ultimately to tip region 18, resulting in a form devoid
of severe articulations. This minimizes cavitation of water
throughout the entire stroke, and minimizes cavitation of water
during slicing modes of paddle use; i.e., during entry and exit of
the paddle into the water, and during bracing and draw strokes.
[0018] The embodiment of FIGS. 1-3 further represents an ideal
relationship of tip location, power face dihedral, and back face
geometry including blade edges, hollow spine, and hollow fan tip.
From the end view of the paddle, the relationship of blade edge
height, maximum dihedral on the power face, and maximum spine
height on the back face minimizes water cavitation during slicing
modes of paddle use by allowing positive flow along all surfaces.
During modes of paddle use where water pressure is normal to the
power face, the dihedral curvature on the power face equally
directs water flow from the center line to the edges of the paddle.
This effectively stabilizes the paddle as it travels through the
water reducing the tendency flutter from side to side which reduces
user strain. Cavitation of water is minimized as the flow wraps
around the blade edges and meets along the spine on the back face
of the blade. During the entire paddle stroke, the tip position and
its relation to the paddle blade curvature directs water flow
toward the tip of the blade, which results in superior paddle
efficiency. It also results in positive water flow toward the tip
along all blade surfaces, minimizing the occurrence of water
cavitation, and maximizing paddle efficiency. Moreover, the tip
position, its relation to the paddle blade curvature, and the power
face dihedral results in a rapid shedding of water during the exit
mode of the paddle stroke. This minimizes user strain and reduces
incidental wetness of user during the paddle stroke.
Embodiment of FIGS. 4-6
[0019] Another embodiment of a gas assisted injection molded blade,
is shown at 100 in FIGS. 4-6. Therefore, as showing in FIG. 4, a
hollow region 116 is shown to extend through stiffening spine 112,
fan-shaped extension/taper 114, tip region 118, all the way out to
adjacent blade edges 122. In the depicted embodiment, hollow region
116 extends to within one half inch of the blade edges 122,
although in the same embodiment it might extend only to within
three-quarters of an inch. Corresponding numbers have been used for
this embodiment, except that they are in the 100 series. In this
second embodiment 100, the entire blade is hollowed by a gas
assisted injection molded process. Blade 20 may include stiffening
ridges or depressions (not shown) formed along the length or width
of the blade to impart greater rigidity to the blade. This paddle
blade 100 would increase buoyancy, reduce the occurrence of water
cavitation, reduce water splashing and user wetness, on entry and
exit. It will also improve paddle stroke efficiency by providing
the maximum amount of airfoil lift for the exit portion of the
stroke.
[0020] Each of the depicted embodiments are designed to be used
with a paddle shaft 24 or 124 and paddle handle 26 or 126, although
these have only been schematically depicted in the figures.
[0021] Variations may be made that will be obvious to those skilled
in the art. Such variations are intended to be covered by the
claims that follow.
* * * * *