U.S. patent application number 11/133123 was filed with the patent office on 2006-01-26 for sail corner attachment finishing system and method of attachment.
Invention is credited to Bruce Chapman.
Application Number | 20060016377 11/133123 |
Document ID | / |
Family ID | 35655783 |
Filed Date | 2006-01-26 |
United States Patent
Application |
20060016377 |
Kind Code |
A1 |
Chapman; Bruce |
January 26, 2006 |
Sail corner attachment finishing system and method of
attachment
Abstract
This invention consists of a corner spar, enfolded within a
layer of high tensile fibers, which are in turn laminated to the
base sail. A flexible, self-adjusting, bridle engages the corner
spar and serves as an attachment point for control lines, sheets,
or halyards.
Inventors: |
Chapman; Bruce; (Reno,
NV) |
Correspondence
Address: |
PYLE & PIONTEK
221 N. LASELLE STREET
SUITE 850
CHICAGO
IL
60601
US
|
Family ID: |
35655783 |
Appl. No.: |
11/133123 |
Filed: |
May 19, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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60575339 |
May 28, 2004 |
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Current U.S.
Class: |
114/39.21 ;
114/102.29 |
Current CPC
Class: |
B63H 9/067 20200201 |
Class at
Publication: |
114/039.21 ;
114/102.29 |
International
Class: |
B63B 35/00 20060101
B63B035/00; B63H 9/04 20060101 B63H009/04 |
Claims
1. A corner attachment for a flexible pliant material such as a
sail having a geometric body, said attachment comprising a separate
assembly comprising a relatively rigid spar, a plurality of fibers
extending around the spar, said fibers being laminated to the body
of the sail, and bridle means attached to an extending away from
the spar for the attachment of rigging.
2. The attachment of claim 1, wherein the corner spar consists of a
one-piece structural bar with, or without, a flexible strain relief
element attached to it.
3. The attachment of claim 1, wherein the corner spar consists of a
multi-piece construct incorporating a structural bar along with a
flexible strain relief and/or end bushings.
4. The attachment of claim 1, wherein the corner spar consists of a
structural bar with an integral strain relief.
5. The attachment of claim 1, wherein the corner spar consists of a
curved or C-shaped beam.
6. The attachment of claim 1, wherein the corner spar incorporates
load pads.
7. The attachment of claim 1, wherein the bridle consists of a loop
of rope or fibers.
8. The bridle of claim 7, wherein the rope loop is created by
splicing end to end.
9. The bridle of claim 7, wherein a cross pin is lashed into the
rope loop.
10. The bridle of claim 7, wherein a cross pin is crimped into the
rope loop with a turret.
11. The bridle of claim 7 wherein the rope loop is created by
knotting the ends of the rope together.
12. The rope loop of claim 11, wherein a ball or handle is placed
or formed over the knot.
13. The attachment of claim 1, wherein the bridle consists of a
single length of rope or bundle of fibers.
14. The attachment of claim 1, wherein the bridle consists of a
single length of rope or bundle of fibers with an eye splice on at
least one of the ends.
15. The attachment of claim 1, wherein the bridle consists of chain
or cable.
16. The attachment of claim 1, wherein the bridle consists of a
rigid bar or beam.
17. The attachment of claim 1, wherein the bridle passes laterally
through the corner bar and hooks back upon itself.
18. The attachment of claim 1, wherein the bridle engages the
corner bar through the use of hooks, eyes or pins.
19. The attachment of claim 1, wherein the bridle engages the
corner bar through the use of adhesives, bonding, mechanical
clamping and/or retention knots.
20. The attachment of claim 1, wherein the bridle is adjustable in
length.
21. The attachment of claim 1, wherein a strain relief is
incorporated between the corner bar and the base sail.
22. The strain relief of claim 21, wherein it is an integral part
of the corner bar.
23. The attachment of claim 1, wherein the high tensile fibers are
radially arrayed into a somewhat bowtie or butterfly shape when
spread open.
24. The fibers of claim 23, wherein they are formed in parallel
bundles.
25. The bundles of claim 24, wherein the fibers overlap each other
in the array.
26. The bundles of claim 25, wherein all bundles overlie each other
in a narrow center section of the array.
27. The array of claim 26, wherein the array is folded about the
center section and over opposite sides of the base sail.
28. A method for creating the corner spar of claim 1, including the
steps of: constructing the bar, assembling the strain relief,
installing the end bushings and/or load pads.
29. A method for creating the fiber web of claim 1, including the
steps of: laying out the fibers, suitably engaging the bridle and
spar together, creating the web of high tensile fibers, folding the
web over a center base layer, engaging the web to the base layer,
and suitably engaging the web covered base layer to the spar.
30. A sail corner attachment comprising a corner spar having a
flexible, adjustable bridle engaged thereto and extending in a
first direction therefrom and having at least a double layer web of
high tensile fibers engaged thereto and extending therefrom in a
direction opposite that of the flexible bridle and being engaged
over a center base layer positioned therebetween.
31. The attachment of claim 30, wherein the bridle includes a knot
therein having an adjustable position to lengthen the bridle.
32. The attachment of claim 30, wherein the corner spar is
preferably made of filament wound carbon fiber tubing.
33. The attachment of claim 32, wherein the corner spar includes
load pads.
34. The attachment of claim 30, wherein the high tensile fibers are
radially arrayed into a somewhat bowtie shape.
35. The attachment of claim 34, wherein the fibers are formed in
parallel bundles.
36. The attachment of claim 35, wherein the parallel bundles of
fibers overlap each other in the array.
37. The attachment of claim 36, wherein all bundles overlie each
other in a narrow center section of the array.
38. The attachment of claim 37, wherein the array is folded about
the center section over opposite sides of the center base
layer.
39. The attachment of claim 38, wherein the center base layer has a
free end which is suitably fixed to a corner area of the sail.
40. A method for creating a sail corner attachment comprising: a
sail corner attachment comprising a corner spar having a flexible,
adjustable bridle engaged thereto and extending in a first
direction therefrom and having at least a double layer web of high
tensile fibers engaged thereto and extending therefrom in a
direction opposite that of the flexible bridle and being engaged
over a center base layer positioned therebetween; the method
including the steps of: suitably engaging the bridle and spar
together; creating the web of high tensile fibers; folding the web
over a center base layer; engaging the web to the base layer; and
suitably engaging the web covered base layer to the spar.
41. A method for attaching a sail corner attachment comprising: a
sail corner attachment comprising a corner spar having a flexible,
adjustable bridle engaged thereto and extending in a first
direction therefrom and having at least a double layer web of high
tensile fibers engaged thereto and extending therefrom in a
direction opposite that of the flexible bridle and being engaged
over a center base layer positioned therebetween, the center base
panel incorporating a free end, to any or all corners of a sail,
the method comprising the steps of: aligning the free end of the
center base panel with sail cloth to form a corner; and engaging
the panel and sail cloth together by any means suitable for use
with the particular materials of the panel and sail cloth.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a new way to terminate
sails at the corners (head, tack, and clew) or other termination
points such as Cunninghams or reefs. This innovation replaces the
current arrangement of stitched together reinforcing patches,
webbing, and rings with a pre-formed composite structure. More
specifically, the new system consists of a corner spar, enfolded
within a layer of high tensile fibers, which in turn are laminated
to the base sail. A flexible, self-adjusting, bridle engages the
corner spar and serves as an attachment point for control lines,
sheets, or halyards.
PRIOR ART
[0002] Today, a number of components must be sewn to the body of a
sail in order to provide a proper anchorage for control lines,
sheets, halyards and other attachments. The corners of the sail are
of particular concern since these areas see the highest loads and
contribute significantly to the overall shape of the sail in
flight.
[0003] Current practice is to apply large cloth "patches" to help
distribute the concentrated load at each corner, into the body of
the sail. All fabrics have a tendency to stretch more along the
bias then along the primary (warp) axis. Because of this, if a
single piece of cloth were used for the patch, then the
reinforcement would distort under load, upsetting the aerodynamics
designed into the sail. In order to control problems of bias
stretch, most patches are designed as multiple triangular gores,
all with the lowest stretch axis, radiating outward from a common
apex. This problem and others are discussed in Fracker U.S. Pat.
No. 3,954,076.
[0004] In addition to patches, other layers of cloth, known as
wadding, may be added. The wadding provides body and lateral
stiffness to the sail. Without it, the sail would tend to fold and
wrinkle from the point load at the corner. Finally, a piece of
attachment hardware, such as a ring, must be secured to the sail
using straps, webs, or ropes. All these individual pieces must then
be sewn down to the base sail.
[0005] The use of fabric patches and wads was consistent with the
materials and construction of traditional cloth sails. These sails
required extensive use of cutting and sewing for their
construction; the corner reinforcements were simply one more time
consuming step in the process.
[0006] The advent of molded sails as described in Baudet U.S. Pat.
No. 5,097,782 eliminated the fabrics, and the need to cut and sew
large panels that were conventionally used in the body of the sail.
Even though these molded sails are constructed as a monolithic
composite membrane of films, polymers, and high tensile fibers, the
corners were still constructed and finished using customary
materials and techniques.
SUMMARY OF THE INVENTION
[0007] Instead of using layers of fabric plies to reinforce the
corner of a sail, and instead of using a sewn and strapped on metal
ring as an anchoring point, a composite assembly is used. The
assembly consists of a corner relatively rigid member or spar held
to the base or body of the sail by a net of high tensile fibers.
These fibers wrap around the spar and are bonded to each side of
the sail. A flexible bridle connects across or around the corner
spar and provides a means to attach control lines, sheets or
halyards to the sail.
[0008] This design solves a number of problems when compared to
using a fixed ring. The assembly can be pre-manufactured, reducing
or eliminating the extensive amount of hand labor currently needed
to finish sails. It reduces the accuracy needed for placement since
the bridle length can be adjusted.
[0009] The bridle can be made to be openable, eliminating the need
for heavy shackles. The bridle can be somewhat flexible and also
creates an inherent self-adjusting tension angle, desirable for
proper sail trim. And finally, the bridle is easily
replaceable.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a perspective view of an exemplary embodiment of
the sail corner attachment of the present invention.
[0011] FIG. 2 is a plan view of a high tensile fiber web and
carrier membrane shown in a flattened position.
[0012] FIG. 3 is an enlarged detailed perspective of the corner bar
assembly from FIG. 1, without the fiber web, sail or sheets
attached.
[0013] FIG. 4 is an alternate version of the corner bar assembled
out of multiple pieces.
[0014] FIG. 5 is an alternate, monolithic, version of the corner
bar, formed with an integral strain relief and a non-openable
bridle.
DESCRIPTION OF THE INVENTION
[0015] All sails for sailing vessels, regardless of the method of
making the sail (whether molded or made from panels), require
finishing operations after the body of the sail is constructed. One
of these operations is to provide some way of attaching lines or
attachment hardware to the sail. Traditionally, this is done by
sewing reinforcement patches into the corners of the sail, then
attaching loops, rings, or other hardware through the use of straps
and additional stitching.
[0016] The reinforcement is necessary since primary loads are
transmitted through the corners into the body of the sail. The
corners are of particular concern, since this is where the forces
generated by wind and water are concentrated. More important the
corners are the anchor points where those loads are transferred to
halyards, sheets, shackles, or other control lines.
[0017] Customarily, various configurations of reinforcing panels
have been employed to overcome the strains at the corners of a
sail. Such thickening patches effectively add more plies of
sailcloth, as the panel approaches the apex of the corner. To be
effective, the weave of each patch must be properly oriented to
avoid bias stretch and distortion, often requiring a patch to be
made up of many triangular sections. By sewing the edges of the
plies to each other, and to the sail panel, the corner is
reinforced in increments intended to distribute the strain over a
larger area of the sail.
[0018] The construction of such traditional patches and anchor
points is extremely labor intensive. Additionally, even when a
patch is made of multiple segments, current material limitations
can only approximate ideal stress distributions.
[0019] This invention relates to hardware, finishing system, and
method of uniformly reinforcing the corners of a sail. This
invention also relates to the method of building such improved
reinforcing attachments into the sails at a substantial saving of
labor and material. This device is designed to replace the
traditional system of cut and sewn cloth patches, wads, straps, and
rings.
[0020] With this invention, a flexible composite structure is built
up that more efficiently transfers loads from the body of the sail
into an anchor point. FIG. 1 shows this invention as attached to
the body of a sail (1). An array of high tensile fibers (2)
radiates from a corner spar assembly (3). The fibers are bonded to
the body of the sail (1) along with a protective cover film (4).
These fibers run from one side of the sail to the other and serve
to retain the corner spar (3). A bridle (5) of rope or cable
connects the corner spar (3) to a conventional control line, sheet,
or halyard (6).
[0021] The spar bridle arrangement solves a number of design
problems when compared to using the traditional closed ring. It
reduces the accuracy required for corner placement since the length
of the bridle can easily be changed. It provides a self-adjusting
tension angle, and the bridle is easily replaceable. Additionally,
the bridle can be made so that it can be opened or disconnected,
allowing control lines or sheets to be attached without the use of
heavy shackles.
[0022] Note that even though this invention was developed for use
on boat sails, it could be equally well employed for other
applications. Particularly in those cases where an anchor point
must be attached to a flexible base. For example, tie downs for
tarps or tents, awing reinforcements, connections to large fabric
buildings and structures, etc.
[0023] The web is made by stretching individual fibers from one
side of the sail, around the corner spar, then returning them to
the opposite side of the sail. Adhesives are used to bond the
fibers to each side of the sail and to the corner spar. For
clarity, FIG. 2 shows the pattern of high tensile fibers and cover
carrier film, as they would look if spread open. In use, this web
of yarns would be wrapped around the corner spar assembly and
bonded to both sides of the base sail.
[0024] In practice, the entire network of fibers would likely be
preformed upon a film or fabric substrate, and then used to attach
the spar to the sail in a secondary operation, as shown in FIG. 2.
By inverting construction of the web assembly (so that the
substrate film is the outermost layer), the film could double as a
shielding cover, to protect the filaments underneath. The use or
omission of a substrate or cover film should not be construed as
limiting in regards to this patent.
[0025] To expedite the construction process, more than one filament
could be applied in a single pass. This would give the web the look
of groups of parallel yarns, each group radiating outward from the
apex of the corner. The overlapping fibers, closer to the corner,
would serve to build up the thickness and provide some lateral
support to the base sail. Conversely, as the yarns radiate outward,
they will naturally thin out and transfer the loads into a large
area of the base sail.
[0026] It should be noted that typically a small portion of the
corner of the sail body is removed before the corner construction
is applied. The corner spar is the only rigid, structural, element
within the invention. Its purpose is to tie all the fibers together
and thus collect the loads that each filament carries. This
structural bar would then transfer that load to a bridle or some
other connecting device.
[0027] FIG. 3 shows a concept of the corner bar assembly before
being attached to the sail. This assembly consists of the main
corner spar (7). A tapered, flexible, strain relief element (8) is
bonded to the spar. The strain relief will help ease the transition
of the fibers as they wrap around the spar and lead into the sail.
The strain relief will also prevent excess flexure along the
interface between the end of the sail and the spar.
[0028] To conserve weight, crucial in sailing applications, the bar
would be a hollow tube with a teardrop cross-section. The teardrop
shape would provide the largest radius for the fibers to be bent
around, and still taper easily back to the narrow thickness of the
sail. The hollow design would also provide a way to loop a
connecting line, the bridle, through the spar. A generous radius
would be provided on the inside of the tube to minimize chaffing on
the bridle.
[0029] Where the sail contacts the length of the spar, a flexible
strain relief is added. This strain relief is necessary to prevent
excessive flexing between the sail and spar. Particularly in
situations where the control lines are unloaded, and flogging of
the sails occurs. If this side-to-side bending, along a
concentrated line, were allowed to go unchecked, then the fibers
would prematurely fail due to fatigue.
[0030] The strain relief continues the taper created by the
teardrop shape and would allow the fibers to smoothly blend onto
the surface of the sail. The strain relief and the corner spar
could be interlocked with a keyway shaped profile. This would
provide additional strength and control of the joint. The spar
extends approximately to the central axis of the corner.
[0031] In its simplest form the bridle is a single loop of rope fed
through the length of the spar and knotted together, and for
permanent applications this may be adequate. However, in most
sailing applications it is desirable to be able to open the loop so
that the sails and control lines can be easily changed.
[0032] One easy way to accomplish this is to double over a sort
length of line and knot the ends together. A ball (9) or disk with
a hole through it could then be strung over this double line, the
knot preventing it from sliding off the opposite end. In this manor
a loop of rope can be produced with a knob or handle on one end.
Not only is this design easy to build but also the overall length
can be easily adjusted by repositioning the knot.
[0033] This doubled length of line would now be fed through the
length of the spar, the ball preventing it from passing entirely
through. The loop that is now naturally formed in the free end of
rope, can be fed through an eye in the control line, and hooked
over the ball. This has proven to be effective for small sails and
light loads.
[0034] For larger sails and loads, the bridle needs to be more
sophisticated. For this application, the bridle would be a
continuous loop of line spliced end-to-end. A small cross bar would
be lashed into one end of the loop. An annular groove in the center
of the cross bar would prevent it from slipping sideways. In use,
it would be fed through the spar and control line just as before,
but now hooked over a cross bar rather than a ball.
[0035] In certain circumstances, there could be advantages to
variations of this basic design. From a strength standpoint,
forming the spar into a bow or even into a C shape might help
reduce weight. A shape like this might then require the fibers to
be arrayed into a purely radial pattern. Perhaps additional yarns
would then be added to provide overlap and cross fiber bonding.
Further fiber patterns could solve other problems.
[0036] For unique sizes, the spar could be a multiple piece
construction. FIG. 4 shows an alternate concept of the corner bar
assembly. This assembly consists of a simple piece of tubing cut at
an angle at both ends. End bushings are fitted into each end of the
spar and allow the bridle to be threaded through, protected from
sharp edges. A strain relief element is bonded to the tube. The
bridle in this figure is the basic loop of rope knotted together at
one end with the knot embedded into a small ball handle.
[0037] In application where extreme flogging is not present, the
strain relief might be eliminated. In other cases, it could be
possible to mold a strain-relieving feature directly into the spar.
An example of this would be to simply taper the spar cross-section
to a narrow enough point that the material would flex.
[0038] Rather than feeding the bridle through the spar, hooks or
cleats could be formed on the end of the spar. A continuous loop
bridle could then be spread from hook to hook.
[0039] Another option would be to build a mechanical clamp into the
spar that would anchor one, or both, ends of the bridle line. This
clamp could take the form of a hold down strap, a tapered collet,
retaining screws, or other physical restraint. In low wear
situations, the bridle could even be bonded to the spar.
[0040] The bridle need not even be rope. Where weight is not an
issue, the bridle could be made of cable or chain. These materials
would provide even more variety of ways to anchor the ends.
Finally, if the application is such that the pull direction is
consistent, a non-flexible bridle could be used. This would include
using solid bars, connecting plates, formed rods, and the like.
[0041] Optional enhancements and features can also be added.
Attachment points for leech and foot lines could be incorporated
into the corner spar. The outer edges of the center base layer or
corner anchor panel could be scalloped to ease transition from film
to sail. A further loop could be spliced into the bridle if
necessary for additional sail control. A double bridle and panel
incorporating both tack and Cunningham attachments could be used.
The finished corner could be encapsulated with an elastomeric
material using injection molding or high pressure laminating
processes.
[0042] Thus, the teachings disclosed herein should not be construed
as being limited, except for the content of the accompanying
claims.
* * * * *