Ships – Anchor – Fluke type
Reexamination Certificate
1999-08-27
2001-07-03
Basinger, Sherman (Department: 3617)
Ships
Anchor
Fluke type
C114S294000
Reexamination Certificate
active
06253701
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention concerns an anchoring device including a cylindrical hollow body having a first edge, a second edge, a forward end having attachment means for applying a traction force to the body, a backward end opposite to the forward end, and fluke means for improved anchorage properties.
The term cylindrical body used herein is intended to include any kind of cylindrical body, i.e., not only a straight circular cylinder body, but also such cylinders that have a non-regular figure as its base, or an axis that is not perpendicular to the base.
The anchoring device is primarily, but not exclusively, intended for permanent or long-time anchorage, such as for anchoring oil rigs.
2. Description of Background Art
A plurality of different anchoring devices are known since long ago for anchoring ships and smaller vessels, such as yachts, as well as for anchoring mooring buoys and floating platforms, such as oil rigs. When it comes to anchoring floating landing stages or jetties, heavy and cumbersome molded concrete blocks are frequently used having a steel eye molded into the block for attachment of an anchor chain or wire. Since a solid body of concrete, having a specific gravity of 1.8-2.5 depending, a.o., on the ballast material, looses about 40% of its effective weight when it is immersed in water, it must be made excessively big and heavy in order to achieve its desired anchorage properties, or, it must be shaped such that its shape provides improved anchorage properties.
An anchoring device made of steel, having a specific gravity of typically 7.8, can be made much smaller for a certain weight, and it can easily be shaped for improved anchorage properties, such as being provided with sheet metal projections as fluke means. One such anchoring device having a cylindrical body in the shape of a straight circular cylinder is marketed in Sweden under the trade name “P-ringen” (the P-ring). It consists of a circularly bent length of strip iron, the ends of which are welded together to form a closed ring. A steel eye is welded to the outer circumference of the ring for attachment of a chain or wire. Symmetrically about the eye, four flukes are welded to the ring, two at one axial end of the cylinder and two at the opposite axial end thereof. The flukes are slightly bent so as to be directed towards the direction of traction in a chain or wire attached to the eye. This is supposed to improve the anchorage by making the forward end of the device dig into the bottom.
A problem encountered, however, is that heavy sea, combined with heavy traction in the chain or wire, tends to raise the forward end of the ring with the flukes from the bottom, thus leaving only the back end of the ring in bottom contact.
SUMMARY OF THE INVENTION
It is an object of the present invention, thus, to provide an improved anchoring device including a cylindrical body having attachment means for applying traction force to the body. This is simply achieved by providing at least one fluke means arranged at the backward end of the body.
With the above construction the fluke means never looses contact with the bottom even when heavy forces raise the forward end of the device. On the contrary, on soft bottoms, such as clay, mud and sand, repeated raising and lowering of the forward has been found to cause the backward end to cut even deeper into the bottom than a mere pulling force at the forward end, even if the fluke means is directed in an axial direction of a straight cylinder.
In order to further improve the capability of cutting or sinking into a relatively soft bottom, vibrator means may be utilized to vibrate the anchoring device. Such vibrator means may be integrated in the device, or, preferably, be temporarily connected thereto by being lowered along the anchor chain or wire until it contacts the anchoring device.
In one embodiment of the present invention, the anchoring device includes means for shifting the effective point of action of the anchor chain or wire to a position at the backward end in order to facilitate heaving of the device from the bottom.
It should be emphasized that the arrangement of fluke means at the backward end does not exclude fluke means arranged at the forward end of the body as well.
An anchoring device according to the present invention is preferably made of steel or reinforced concrete. Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: 2468077 (1949-04-01), Kellum
patent: 3180304 (1965-04-01), Brady
patent: 3417724 (1968-12-01), Edwards
patent: 3516379 (1970-06-01), Skoog
patent: 3908575 (1975-09-01), Giolfo
patent: 2929495 (1981-02-01), None
patent: 1509524 (1978-05-01), None
patent: 2 227 988 (1990-08-01), None
Japan abstract vol. 7, No. M-256, abstract of Japan JP 58-139889 (Goyou Kensetsu K. K.), Aug. 19, 1983.
Basinger Sherman
Birch & Stewart Kolasch & Birch, LLP
Roslagens Maricenter AB
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