Hydraulic and earth engineering – Bank – shore – or bed protection – Wave or flow dissipation
Reexamination Certificate
1999-12-09
2002-12-24
Shackelford, Heather (Department: 3673)
Hydraulic and earth engineering
Bank, shore, or bed protection
Wave or flow dissipation
C405S016000, C405S021000, C405S030000, C405S033000, C428S188000
Reexamination Certificate
active
06497532
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to structural members. This invention also relates to erosion control systems, and more particularly, to a composite of substantially parallel elements connected therefore.
In a previously filed application, an invention was disclosed relating to rods and shafts which are suitable for use in the construction of tapered and parallel edged fishing rods, golf shafts, yacht masts, sailboard masts and the like.
Fishing rods, golf shafts, yacht masts, sailboard masts, and the like are generally constructed of fibre-resin composites or metal in the form of solid rods or tubes. Hollow composite rods are accepted as being superior in performance to solid composite rods in light weight uses but they are delicate and easily damaged. Solid metal rods and metal tubes are generally inferior in flexural characteristics to the composite rods. It will be apparent to the skilled person that the teaching of rod or shaft construction in the above arts may be effectively applied to other heavier, industrial or civil engineering uses as well.
Tapered, tubular composite rods require expensive, accurately ground metal mandrels to produce the taper necessary for the desired performance and there are considerable difficulties in manufacturing with uniform wall thickness. An attempt to overcome to some extent the problems associated with tubular rod manufacture from composite materials is the subject of U.S. Pat. Nos. 4,582,758 and 5,229,187 (referred to herein respectively as Bruce & Walker and McGinn), the enabling teaching of which are incorporated herein. Both patents relate to the provision of rods of polygonal cross-section formed by a plurality of elements of certain geometrical cross-section. Bruce & Walker describes that each of the elements has a base part of a fibre reinforced plastic material and an apex of part of a rigid plastic material foam.
McGinn, on the other hand, adopted a method of using T-sections made from fibre reinforced plastic material. The method by which the joints of the top ends of T-sections in McGinn are joined is shown in FIG. 5 of that patent. It is seen that the top ends of the T-sections must be molded or machined to a relatively small tolerance to accommodate matching of the several faces of the T-sections to each other. Both these rods, while they solve wall thickness variation problems and obviate the need for expensive mandrels for forming are difficult to make in the required thickness.
Bruce & Walker experience difficulties in the required stiffness for heavy load application such as are encountered in deep sea fishing and similar application without resorting to excessive composite wall thickness. The technology applied by McGinn addresses the stiffness required in heavy load application, but the mere nature of this technology reduces the ability to make the rods flexible for fly rod application in the various line weights required. Neither invention has adequately addressed the problem of torque encountered in small structures such as golf shafts.
The problem is severe in the case of Bruce & Walker. The McGinn technology has gone some way to addressing this problem with sufficient torque being removed from fishing rods to make them user acceptable. However, the problem of torque is highlighted when both products are used as golf shafts. Any torque in the shafts alters the angle of the golf club head when it comes in contact with the ball, which is unacceptable to the playing golfing public.
It is therefore one object of the present invention to provide a rod, shaft, etc., which obviates or at least minimizes the aforementioned disadvantages of conventional rods and those of Bruce & Walker and McGinn.
Erosion prevention and control systems are useful for minimizing erosion around underwater structures, including pipes, pilings, bridges and cables, that rely on the seabed for support and also for minimizing coastal shoreline and beach erosion, as well as retaining the finer silts and muds of wetlands. Methods and devices for preventing underwater bed and shoreline and wetlands erosion are known. Some of these devices, such as breakwaters and groynes, although relatively time intensive and expensive to install, are effective in minimizing shoreline erosion and are generally constructed from rock, concrete, rubble mounds and other hard body materials. Other devices, primarily used for erosion control on seabed structures, operate by increasing viscous drag on the underwater current, thereby reducing the velocity of the current and of the particulate transported by the current. This causes some of the particulate to settle out of the current and to be deposited in or around the erosion control system. The precipitated particles form a berm in and around the erosion control system. Typical of those devices that increase viscous drag on the current are buoyant frond elements or artificial seaweed or some other viscous drag element. The viscous drag elements are generally secured to the a silted surface (i.e., a seabed or riverbed) via some type of anchor line.
As the cross sections of the hydraulic passages in the viscous drag materials decrease, the amount of drag on the viscous drag elements increases. The structural strength of such materials must be increased to withstand the drag required which is sufficient to disrupt laminar flow of the silt bearing or erosion causing water flow. The ability of the viscous drag elements in prior art appear to rely on greater weight than necessary to obtain the desired sediment precipitation. However, these factors lead to the enhanced ability to build higher berms of precipitated particles. For coastal shoreline applications it is essential to have high berms which will form submerged, wide-crested breakwaters which, optimally, reach a height of 80% of the depth of the water. For wetlands sediment retention, the extremes of hurricane driven water flows to extremely low and constant velocity water flows must be accommodated to retain sediment.
With respect to sediment in having substantially the grain size of sand beaches, waves travel by pressure and move in an oscillating fashion to strike and wash across the beach surface. The forward and backward motions of the water, moving just above the bottom of the sea, are unsymmetrical, with the forward motion being stronger and of shorter duration than the backward motion. The carrying capacity for suspended solids in the moving water is generally proportional to the velocity of the flow. That velocity of flow can be regulated or influenced by environmental and/or man-made barriers. Thus, when the velocity of the flow is sufficiently reduced, deposition or precipitation of suspended solid matter occurs.
The best protection against shoreline erosion is a wide beach since that environment causes the waves to break, thereby dissipating the wave energy before the erosion of the shoreline can occur. Normally, beaches grow seaward by deposition of sand from longshore currents and new sand brought from offshore by the formation of a ridge and runnel system perpendicular to the beach. Long waves of small amplitude serve to replenish the shoreline, while short storm waves of high amplitude erode the shoreline.
Experience has shown that natural sandbars provide excellent protection against destructive wave forces. Consequently, attempts have been made to simulate sandbar action by constructing artificial barriers parallel to the shoreline. Such barriers have been unsuccessful because high velocity water currents typically scour and undermine their foundations, causing the barriers to fail and to lose their effectiveness.
SUMMARY OF THE INVENTION
The present invention is a general structural member assembly. Two embodiments of a basic structural unit of the present invention have two adjacent shafts, both further having a cross sectionally triangular shape with a longitudinal side completely or substantially mostly removed. The “open” side, i.e., the side completely or substantially mostly removed, in cross section presents two “leg” ends,
Mitchell Katherine
Shackelford Heather
LandOfFree
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