U.S. patent application number 11/375291 was filed with the patent office on 2007-09-20 for surfboard having a skin of reinforced fabric.
Invention is credited to H. Landis Carter, Shobha Murari.
Application Number | 20070218787 11/375291 |
Document ID | / |
Family ID | 38518499 |
Filed Date | 2007-09-20 |
United States Patent
Application |
20070218787 |
Kind Code |
A1 |
Carter; H. Landis ; et
al. |
September 20, 2007 |
Surfboard having a skin of reinforced fabric
Abstract
A fiberglass covered recreational board for surfing and other
water sports having increased strength and rigidity provided by a
longitudinal, central band or bands of higher strength glass fibers
such as S Glass and S-2 Glass, or by aramid fibers, or by quartz
fibers that are woven into the fiberglass cover as warp
threads.
Inventors: |
Carter; H. Landis; (Greer,
SC) ; Murari; Shobha; (Greenville, SC) |
Correspondence
Address: |
MCNAIR LAW FIRM, P.A.
P.O. BOX 10827
GREENVILLE
SC
29603-0827
US
|
Family ID: |
38518499 |
Appl. No.: |
11/375291 |
Filed: |
March 14, 2006 |
Current U.S.
Class: |
441/74 |
Current CPC
Class: |
B63B 32/50 20200201;
B63B 32/57 20200201 |
Class at
Publication: |
441/074 |
International
Class: |
B63B 35/79 20060101
B63B035/79 |
Claims
1. A recreational board for surfing and other water sports
comprising: a) an elongated core comprising a floatable material,
said core having an upper surface defining a deck, a lower surface,
and a longitudinal axis; b) a skin conformingly covering said deck
and adhered thereto, said skin comprising a woven fiberglass fabric
having a multiplicity of reinforcing strands woven into the fabric
in a band extending the length of said board parallel to the
longitudinal axis, said strands increasing the rigidity and
strength of said board.
2. The recreational board of claim 1 wherein said core is a foamed
polymeric material.
3. The recreational board of claim 1 wherein said fiberglass fabric
is E fiberglass and the reinforcing strands are selected from the
group consisting of S Glass, S-2 Glass, quartz, carbon and, aramid
fibers and blends of said fibers with each other.
4. The recreational board of claim 3 wherein said multiplicity of
strands define a band having a width in the range of about six
inches to about twelve inches that extends the length of said
core.
5. The recreational board of claim 4 wherein said band is divided
into first and second bands, said first and second bands being
spaced apart equal distances from longitudinal axis of said
board.
6. The recreational board of claim 4 including a plurality of said
bands.
7. The recreational board of claim 1 wherein said multiplicity of
reinforcing strands are positioned only on the upper surface of
said core.
8. The recreational board of claim 1 including at least one
reinforcing band positioned on the upper surface and at least one
band positioned on the lower surface of said core.
9. The recreational board of claim 1 wherein the board is a
surfboard and the core is a honeycomb construction.
10. In a recreational board for surfing and other water sports
wherein the board core is a foamed polymer having an upper and
lower surface, a longitudinal axis, and, a fiberglass fabric skin,
the method of strengthening and rigidifying said board comprising
the steps of: a) providing reinforcing strands selected from the
group consisting of fibers of S Glass, S-2 Glass, quartz, carbon,
and aramid and blends of said fibers, one with the other; b)
weaving a fiberglass fabric having a multiplicity of said selected
fibers as warp strands, said selected fibers being in a defined
band; and, c) covering the upper surface of said board with said
reinforced fabric, the reinforced band being positioned parallel to
said longitudinal axis, thereby providing a longitudinally
reinforced board.
11. The method of claim 10 including the step of providing at least
one band of transverse reinforcing strands.
12. The method of claim 10 including the step of providing at least
two longitudinal reinforcing bands.
13. A recreational board for surfing and other water sports
comprising: a) a foamed polyurethane core, having upper and lower
surface, said core being divided longitudinally into two halves; b)
a longitudinal stringer to which each core half is bonded; c) a
first woven fiberglass cloth forming a conforming covering skin on
the upper surface of said core, said cloth having a band of
longitudinal strands made from fibers selected from the group
consisting of S Glass, S-2 Glass, aramid and quartz fibers, the
remainder of said cloth being woven from E glass, said cloth being
adhered to said core by a polymeric resin, and said band being
positioned over said stringer; and, d) a second woven fiberglass
cloth of E glass being adhered to the lower surface of said
core.
14. The recreational board of claim 13 wherein the second
fiberglass cloth is provided with longitudinal reinforcing strands
selected from the group consisting of S Glass, S-2 Glass, aramid
and quartz fibers.
15. The recreational board of claim 13 wherein said first cloth has
at least two reinforcing bands.
16. The recreational board of claim 13 including at least one
additional cloth covers on the upper surface.
Description
FIELD OF THE INVENTION
[0001] This invention relates to surfboards and similar
recreational boards for water sports. More particularly, the
present invention relates to high strength, lightweight, durable
surfboards and to the construction of such surfboards.
BACKGROUND OF THE INVENTION
[0002] The popularity of surfing and water sports in general has
increased significantly in recent decades and includes not only the
use of surfboards but also body boards, water skis, and
wind-surfing craft. Because of the increased interest, the demand
for improved construction has likewise increased. Accordingly, one
general object of this invention is to make a lightweight and
durable surfboard so that the rider will have a board that lasts
longer and will enhance his performance on the waves.
[0003] The first surfboards, it is believed, were originated by
Polynesians and were made of wood from trees found on their
islands. They were carved and shaped by hand and stained and
finished with natural oils. The early boards were 12 to 20 feet
long and weighed 100 to 200 pounds.
[0004] Before the days of widespread availability of polymeric
materials and fiberglass, surfboards continued to be constructed of
wood, particularly lightweight wood, which was laminated in order
to provide strength; that is, a board of wood that was
advantageously lightweight usually would not have sufficient
strength to withstand the force of waves if it were constructed
from a single piece of wood. Subsequently, laminated wooden boards
and then molded fiberglass boards appeared. Next, fiberglass
covered surfboards were developed having lighter weight and
enhanced performance. Wooden board cores began to be replaced by
lighter weight polymeric foams, particularly polyurethane foam
cores. However, foam cores alone did not possess enough material
strength to maintain the structural integrity of the board for long
periods of strenuous use and, consequently, the foam cores required
additional structural support which, in some designs, was in the
form of wooden stringers to provide the necessary strength for a
successful board. Unfortunately, this type of construction limited
the number of designs that were sturdy enough. In addition, foam
surfboards generally did not last more than a season or two with
frequent use. One drawback was that an air bubble tended to form
between the fiberglass and the foam thus destroying the structural
integrity of the board.
[0005] One example of a surfboard body molded around a longitudinal
stringer is shown in U.S. Pat. No. 4,798,549 to Mark Hirsch.
[0006] Another construction for strengthening the core is shown in
U.S. Pat. No. 5,514,017 to William J. Chimiak wherein the core is a
honeycomb of a polyamide for increased strength and rigidity. The
Chimak patent mentions the application of multiple fiberglass scrim
covers and also mentions that reinforcing carbon filers may be
woven in the scrim.
[0007] Still another honeycomb construction is shown in U.S. Pat.
No.6,800,006 B1 to Mark T. Itnyre, et al. Longitudinal reinforcing
stringers are shown in this patent. Another design using fiber
reinforced resin on the top of a board is described in U.S. Pat.
No. 6,790,402 to Richard Greven.
[0008] A patent showing a multi-layer core construction reinforced
between layers and having longitudinal stringers is U.S. Pat. No.
5,944,570 which issued to J. Randolph Appleby. The foregoing
mentioned patents show the desirability of the longitudinal
reinforcement of a surfboard. These prior designs can provide high
performance and a minimum weight of five to eight pounds, high
strength, tough dent and puncture resistance skin, strong side
rails, and an attractive high gloss finish with a slick surface to
enhance speed: The designer's goal is to provide all these features
at a relatively low cost. Another general object of the present
invention is to provide an improved surfboard incorporating the
desirable features described above.
[0009] A further object of the present invention is to increase the
strength of a fiberglass covered surfboard while keeping the
increased cost to a minimum.
[0010] Still another object of the present invention is to provide
increased strength of the surfboard without adding to the weight of
the surfboard.
[0011] The foregoing and other objects of the present invention can
be appreciated by the description below under the heading Summary
of the Invention.
SUMMARY OF THE INVENTION
[0012] In one aspect, the present invention is a surfboard or
similar recreational board for surfing and other water sports which
comprises an elongated, shaped core, said core having an upper
surface, a lower surface, and a longitudinal axis; a skin or skin
layers completely covering said core, at least one skin layer
comprising a woven fiberglass fabric having a multiplicity of
reinforcing strands woven into said fabric and extending the length
of said board parallel to the longitudinal axis, said strands
increasing the rigidity and strength of said board. The core of
said board is preferably a foamed polymer which may be polyurethane
or polystyrene. The core may be of a honeycomb polymeric
construction or a light weight metal honeycomb such as aluminum;
or, it may be wood, a wood laminate, or foam and wood composite.
The skin is preferably adhered to the core with a polymeric resin,
the bottom of the core having at least one skin layer and the top
or deck having at least one of the reinforced skin layers and
preferably a plurality of such layers.
[0013] The fiberglass skin fabric is woven from either a C or E
fiberglass and the reinforcing strands may be either S Glass, S-2
Glass, quartz, carbon or aramid fibers or may be a blend of these
fibers with each other. In general, S-2 Glass or quartz reinforcing
strands are preferred for their bright white appearance and ability
to be woven readily with other glass fabrics.
[0014] The multiplicity of reinforcing strands define a band having
a preferable width from about six inches to about twelve inches
that extends the length of said core when the skin is applied to
the core. Rather than a band, every other longitudinal strand may
be a reinforcing strand.
[0015] In another aspect, the single central band of reinforcing
fiber may be divided into two bands, one on either side of the
longitudinal axis that continues to the respective edges of the
board; or, four bands or more may be used. In addition, transverse
reinforcing bands may be incorporated in a skin layer. There may be
one central band about midway of the surfboard or there may be two
bands, one at about one-third the length of the board and the other
positioned at about two thirds of the length of the board.
[0016] In a still further aspect, a skin with a multiplicity of
reinforcing strands may be positioned only on one surface of the
board which may be either the upper or lower side.
[0017] In yet another aspect, a multiplicity of bands may be
positioned on both the upper and lower surfaces of the board. There
can be more reinforcing strands on the upper surface than on the
lower or vice versa.
[0018] These and other aspects of the invention can be further
appreciated from reference to the description of the drawings and
detailed description which follow.
DESCRIPTION OF THE DRAWINGS
[0019] The invention will be more readily understood from a reading
of the following specification and by reference to the accompanying
drawings which form a part of the specification and are presented
by way of illustration and not limitation and wherein:
[0020] FIG. 1 shows a surfboard according to the present invention
with part of the cover removed in a preferred embodiment showing a
honeycomb core with the position of the reinforcing band being in
bold to show their position as a band. The bold representation is
for illustration purposes only as in all drawings because the
reinforcing strands are generally of the same color and size as the
other fiber strands;
[0021] FIG. 2 is another embodiment similar to that of FIG. 1 in
which there are two reinforcing longitudinal bands shown;
[0022] FIG. 3 is still another embodiment of a present invention
showing both longitudinal and transverse reinforcing bands;
[0023] FIG. 4 is an embodiment of the present invention showing a
central reinforcing band and a solid core;
[0024] FIG. 5 is one schematic representation of a fabric with
reinforcing bands longitudinally woven therein and FIG. 5a is a
representation of a fabric with another type of weave;
[0025] FIG. 6 is a top plan view of another preferred embodiment of
the invention wherein there is a central stringer and no central
longitudinal band and the outer portions of each side of the board
are reinforced by longitudinal strands of higher strength
yarns;
[0026] FIG. 7 shows an embodiment with a central stringer in which
alternating longitudinal strands are reinforcing strands; and
[0027] FIG. 8 shows another embodiment in which a top plan view in
schematic representation of a surfboard having a central stringer
covered by a longitudinal reinforcing band of fibrous strands.
DETAILED DESCRIPTION
[0028] In a typical or representative process of forming a
surfboard, the foam core or blank is formed in a large, cement mold
roughly the desired shape of the finished surfboard. The mold is
constructed in two halves, and the two halves are clamped together
and heated. Liquid polyurethane containing a foaming agent is
introduced into the mold, the heat initiates the foaming reaction,
and a dense, white foam is produced. After the foaming is
completed, the mold is opened and the foam core is taken out and
allowed to harden. Once the core is hard, it is cut in half
vertically from the nose to the tail. A thin wooden stringer is
glued between the two halves. The core is then clamped back
together to dry. The stringer provides longitudinal stiffness and
strengthens the board.
[0029] Next, the outline of the finished board is traced onto the
rough core and the outline is cut out with a saw. Starting with the
bottom of the core, the surface is smoothed and contoured to its
final shape with a planer. When the bottom is finished, the board
is turned and the top is shaped. A sander removes any ridges left
by the planer, and the stringer is contoured with a plane. Rough
sandpaper is used to shape the sides, or rails and then the core is
given a final sanding with fine paper. The shaped core is now ready
to be covered with fiberglass and resin to form the hard, outer
shell of the surfboard. First, the core is blown clean with
compressed air. If the board is to be colored or have a design on
it, paint is applied directly to the foam with a spray gun or
airbrush. When the paint is dry, fiberglass cloth that forms the
skin is laid over the surface of the core and cut to fit. The top
of the board, or deck, is laminated first. A polyester laminating
resin, is mixed with a catalyst. This initiates cross-linking that
will cause the resin to harden in about 15 minutes. The resin is
poured over the fiberglass and spread evenly. All of the fiberglass
must be covered without leaving too much or too little resin in any
spot. When the deck is finished, the board is turned over and the
process repeated on the bottom. The board is then turned once more,
and the deck is given a second layer of fiberglass and resin for
added strength and wear resistance. The laminating resin remains
slightly tacky and rubbery when dry. Additional skin layers may be
applied at this point if desired.
[0030] A second coat of resin or filler coat or sanding resin, is
applied next. The filler coat fills any surface imperfections left
in the laminating resin. Sometimes, this coat is called a hot coat
resin and contains wax and contains a slightly different polymer
mix which causes it to harden completely. The deck is coated first
and then the bottom. When dry any excess resin is carefully sanded
away. After sanding the board is blown clean with compressed air to
remove any residual sanding dust. A final coat of gloss resin is
then brushed onto the board. Like the other two layers of resin,
this final gloss coat is mixed with a catalyst and will harden
within about 15 minutes. After the gloss coat has completely
hardened, as a final step, the board may be wet sanded with very
fine sandpaper, then rubbed, buffed, and polished.
[0031] Looking now at FIG. 1, one preferred embodiment of the
invention in which a surfboard may be made with a honeycomb core
will be described. Surfboard 1 is shown covered by fiberglass cover
or skin 2 on the deck or upper side of the board. The cover is
woven fiberglass cloth or scrim of either C or E fiberglass but is
preferably E fiberglass. The cover encloses a one-piece, honeycomb
core 3 which may be formed from foamed polyurethane, from a
polystyrene foam, or from a light-weight metal such as aluminum.
Preferably, it is a honeycomb polyurethane foam formed according to
known prior art processes. The cover 2 may comprise multiple layers
or just one; but, for the purpose of this illustration only one
layer is shown. A band of reinforcing fibers is longitudinally
woven into the fabric and is aligned parallel with the central axis
14. The band 4 is preferably six to twelve inches in width and
gives the surfboard increased rigidity and strength as compared to
a fiberglass cover without the reinforcing band of multiple
longitudinally arranged strands.
[0032] Turning now to FIG. 2, another preferred embodiment is
illustrated wherein surfboard 5 may be seen with cover 8 around
honeycomb core 9 with fiberglass cover 8 being partially cut away.
Longitudinal bands 6 and 7 are parallel to the longitudinal axis 14
and are placed equal distances from the longitudinal axis. In this
embodiment more reinforcing fibers or strands are used making the
board somewhat stronger.
[0033] In FIG. 3 still another embodiment is shown wherein cover 8
of surfboard 15 is provided not only with longitudinal parallel
strips 6 and 7 but also with transverse bands 16 and 17 which are
positioned to divide the board into approximate thirds
longitudinally. This arrangement provides transverse rigidity and
strength particularly for the board edges or rail area.
[0034] In FIG. 4 yet another embodiment is shown wherein the
surfboard 19 has a solid foam, solid wood, or laminated wood, core
18 and the cover 2 is shown in partial cutaway. The center band of
reinforcing strands runs down the center of the board
longitudinally.
[0035] FIG. 5 is a schematic representation of a segment of fabric
where the longitudinal warp threads 11 comprise E fiberglass as do
weft or horizontal threads 12 which is, perhaps, the most common
lower cost type of fiberglass strands or yarn and the same is used
for the weft or transverse yarns. This piece of fabric or cloth 10
is reinforced down its center line by high-strength yarns 13 which
can be strands of quartz fibers, S glass fibers, S-2 Glass fibers,
carbon or aramid fibers. These fibers are generally available from
manufacturers known to those skilled by the art, particularly, such
fiberglass strands and fibers may be obtained from AGY Holding
Corp. or from Owens-Corning Fiberglas Corporation whose comparative
data is set forth in Table I below: TABLE-US-00001 TABLE I
(Impregnated Strand Test: ASTM D-2343) Tensile Strength (KSJ)
Astroquartz .RTM.* 9779 530.5 S-2 Glass Fibers 463 519.9 S Glass
Fibers 901 557.0 "E" Fiberglass 456 277.5 "E" Fiberglass 462 271.5
(*Manufacturer's Trademark)
[0036] A comparison of typical compositions of glass and quartz is
presented in Table II below: TABLE-US-00002 TABLE II (Weight
Percentages) Ingredient "E" Glass "S" Glass Astroquartz .RTM.
Silicon Dioxide 52-60 64-66 99.99 Calcium Oxide 16-25 -- --
Aluminum Oxide 12-16 24-26 -- Boron Oxide 8-13 -- -- Sodium &
Polymeric Oxide 0-1 -- -- Magnesium Oxide 0-6 9-11 --
As can be seen, quartz and S Glass have about twice the tensile
strength of E glass but the cost difference is significantly
greater. Accordingly, one of the objects of the invention is
achieved by using the higher strength material in a band down the
center of the surfboard where it is more effective in adding
strength and controlling the rigidity of the surfboard. The cost is
lower since the higher price material is used only where it is most
effective. Carbon fibers may also be used but their cost is even
higher. The quartz and glass fibers have the most attractive
appearance. Some manufacturers weave carbon fibers uniformly in a
fabric but this tends to increase the cost and the carbon detracts
from the appearance of the material. Applicants' invention lowers
costs and maintains attractiveness. FIG. 5a is the same as FIG. 5
except that the horizontal or weft threads 12 are looped at the
sides of the fabric 10 so they are continuous and present another
style of weave.
[0037] In all of the embodiments, the surfboard core may be covered
with a fiberglass scrim before the outer cover is applied. The
first layer may be provided with the woven center band and the
outer layer may also be provided with or without such a band. The
woven fiberglass with the high strength fiberglass bands gives the
board an attractive bright, white appearance and is a preferred
material.
[0038] In FIGS. 1-4 only the upper surface or deck of the
surfboards illustrated therein is shown. Each of these surfboards
may have on its reverse side a continuation of the reinforcing band
or bands coinciding to that shown on the upper side. The bottom
cover may be completely E glass or other lower cost fiberglass in
order to lower the cost. For most surfboards and recreational
boards, the preferred embodiments of FIGS. 1 and 4 with the single
band providing longitudinal reinforcement and sufficient rigidity
and strength with lower cost. The reinforcing strands are shown in
bold although they are the same color and size as the other
strands.
[0039] Looking at FIG. 6, upper or deck surface of surfboard 20 is
shown with a central stringer 21 bonded to each half 20a and 20b of
the surfboard. The core of this surfboard is formed according to
the process first described above beginning with paragraph 0028.
Fiberglass cover 22 is adhered to the board with polymeric resin
and reinforced areas 22a and 22b have been woven with longitudinal
reinforcing fiber 23, preferably quartz or S Glass fibers. This
design in combination with a central stringer provides central
longitudinal rigidity together with reinforced sides.
[0040] In FIG. 7, surfboard 25 is shown with central stringer 21
and every other longitudinal strand 28 is a reinforcing strand.
[0041] A best mode of the invention is represented by FIG. 8 in
which surfboard 30 is shown in a top plan view showing the deck or
upper side of the board. Central stringer 31 which is preferably
wood is bonded between polyurethane foam core halves 35 and 36 as
described hereinabove. A first scrim or cover 37 or fiberglass
cloth is cut and trimmed to conformingly match the contour and
dimensions of the deck. Scrim 37 comprises E glass fiber strands 34
and S-2 glass fiber strands 32 which have been woven longitudinally
in central band 33. The scrim 37 is positioned and aligned with the
longitudinal axis of the board. The fabric may be in two pieces,
one over each half or it may be laid over the stringer as shown.
Stringer 31 in this embodiment is coincident with the longitudinal
axis. The bottom of the board is covered with a second scrim of E
glass and bonded to the core with a polymeric resin. The board is
then finished as previously described. The result is an
exceptionally strong board with a superior appearance.
[0042] Although the above description applies to surfboards,
windsurfers, sailboats, water skis and other boards for
recreational or water sport use, it will be understood that the
invention is not limited to such applications as modifications may
be made by those skilled in the art particularly in light of
applicants' foregoing disclosure. Therefore, such modifications and
embodiments may be made to be included within the spirit and scope
of the following appended claims.
* * * * *