GB2042450A - Flexible anchor buoy - Google Patents

Abstract

A flexible anchor buoy (10, 32) includes a tube (11, 39) for the passage therethrough of an anchor chain (13), a core pipe 14, 37 fixed perpendicularly to the tube, and a resilient buoyant body (22, 33) disposed around the core pipe and separated from the tube. The resilient buoyant bodies (22, 33) can be enclosed by a pair of flexible coverings (24, 41) respectively. Preferably a pair of resilient buoyant bodies (22, 23 or 33, 34) are disposed around the core pipe one to each side of the tube. When the anchor buoy is held against a ship and locally compressed under the weight of an anchor, the buoyant bodies flex relatively freely without being stressed by the tube. <IMAGE>

Description

SPECIFICATION Flexible anchor buoy The present invention relates to a flexible buoy especially for connection to an anchor.

Flexible anchor buoys have been devised to provide resilient cushioning against permanent deformations and damages that iron anchor buoys conventionally caused to themselves and ships while anchors are being pulled up.

A flexible anchor buoy of a type known to us comprises a tube for an anchor chain to pass therethrough, a core connected to the tube, and a resilient buoyant member including a buoyant body and a covering enclosing the buoyant body, the resilient buoyant member being disposed around and bonded to both the chain tube and the core. While the anchor is being lifted from the sea, the buoy is held against the ship and is compressed at localised positions under the weight of the anchor.

The buoy as thus carried by the ship when under way is further subjected to sudden compressive forces when the ship is rolled by waves or changes its sailing speed. This has led to a disadvantage in that the resilient buoyant member, particularly the covering, tends to be ripped off the chain tube due to shearing stresses applied to a region near the chain tube.

The present invention seeks to provide a flexible anchor buoy having resilient buoyant means which is free from being damaged even when the buoy is compressed against a ship under the weight of an anchor.

The invention further seeks to provide a flexible anchor buoy having resilient buoyant means rotatable about a core extending transversely to a tube for the passage therethrough of an anchor chain.

According to the invention, there is provided a flexible anchor buoy comprising a tube for the passage therethrough of an anchor chain connected, an elongate core connected and extending substantially perpendicularly to said tube, and resilient buoyant means mounted on said elongate core and separated from said tube.

The invention will now be described in greater detail, by way of example, with reference to the drawings, in which: Figure 1 is a perspective view of a flexible anchor buoy constructed in accordance with the present invention, Figure 2 is a longitudinal cross-sectional view of the flexible anchor buoy; Figure 3 is a cross-sectional view taken along line Ill-Ill of Fig. 2; Figure 4 is a cross-sectional view taken along line IV-IV of Fig. 2; Figure 5 is a fragmentary elevational view of the anchor buoy as held against a side of a ship while pulling up an anchor; and Figure 6 is an enlarged longitudinal crosssectional view of a flexible anchor buoy according to another embodiment.

As shown in Fig. 1 to 4 inclusive, a flexible anchor buoy 10 comprises a tube 11 made of steel for the passage therethrough of a chain 1 2 (Fig. 5) connected to an anchor 13, an elongated core 1 4 in the form of a pipe of steel extending substantially perpendicularly to the tube 11, and resilient buoyant means 1 5 mounted on the core 1 4. The tube 11 has a pair of end flanges 16, 1 7 with their inner peripheral edges rounded for facilitating the movement of the chain 1 2 into and out of the tube 11.

The tube 11 has a smaller diameter than the core pipe 1 4 and extends through the core pipe 14 at a position substantially midway along its length. The core 14 is connected, for example, by welding to the tube 11 at a position substantially mid-way between the end flanges 16, 1 7. Mounted on the core pipe 1 4 are two pairs of annular flanges 18, 19, the annular flanges 18 in each pair being fixed to an end of the core pipe 1 4 and the other annular flange 1 9 being disposed therearound adjacent to the tube 11. The core pipe 14 is closed off at its ends by a pair of circular plates 20, 21, each having a diameter larger than that of the core pipe 14 and fixed to the annular flanges 18, 1 9 by, for example welding.The resilient buoyant means 1 5 comprises a pair of resilient buoyant bodies 22,23 made of for example polymer foam such as polyethylene foam and a pair of flexible coverings 24,25 made of rubber or urethane and enclosing the buoyant bodies 22,23, respectively. Each buoyant body 22,23 is in the form of a centrally apertured cylinder mounted around and bonded to the core pipe 14. Each covering 24,25 is shaped as a cylinder with an internal annular hollow and which fits over a corresponding one of the buoyant bodies 22,23.

The buoyant bodies 22,23 are located one on eah side of and separated from the tube 11.

Each covering 24,25 has a pair of central openings in its end walls 26,27, the openings being bounded by a pair of circular edges that are bonded respectively to the peripheral surfaces of the annular flanges 1 8,1 9 on the core pipe 14. A pair of wire rings 28,29 are embedded in each of the coverings 24,25 and extend around the openings for reinforcing the circular edges bonded to the core pipe 14.

When the anchor 1 3 is pulled up by a winch 30 on a ship 31 as shown in Fig. 5, the anchor buoy 10 is held against a side of the ship 31 and locally compressed under the weight of the anchor 1 3. Since the buoyant bodies 22,23 are not directly joined to the tube 11, they can flex relatively freely without being stressed by the tube 11. Accordingly, the buoyant bodies 22,23 are resistant to rupture under compressive forces imposed thereon. The coverings 24,25 remain strongly bonded to the annular flanges 18,19 since the reinforcement rings 28,29 act to distribute or weaken stresses applied to the end walls 26,27 of the coverings 24,25.

Fig. 6 illustrates another embodiment in which a flexible anchor buoy 32 has a pair of resilient buoyant bodies 33,34 disposed around and bonded to a pair of tubular members 35,36, respectively, rotatably fitted over an elongate core 37. Each body 33,34 is provided with a flexible covering 41, 42 similar to coverings 24,25 of Fig. 2. Each tubular member 35,36 is secured against axial displacement between a retainer ring 38 disposed around the core 37 and adjacent to a chain tube 39 and an end flange 40 fixed by bolts to an end of the core 37. With the structure of Fig. 6, the buoyant bodies 33,34 can rotate about the core 37 and the anchor buoy 32 can move smoothly on a side of a ship when the anchor is lifted or allowed down.

Claims (12)

1. A flexible anchor buoy comprising a tube for the passage therethrough of an anchor chain an elongate core connected to and extending substantially perpendicularly to said tube, and resilient buoyant means mounted on said elongate core and separated from said tube.

2. A buoy as claimed in Claim 1, wherein the elongate core is connected substantially mid-way along the tube.

3. A buoy as claimed in Claim 1 or 2, wherein said buoyant means comprises a resilient buoyant body bonded to and disposed around said elongate core.

4. A buoy as claimed in Claim 3 comprising a flexible covering enclosing said resilient buoyant body and bonded to said elongate core.

5. A buoy as claimed in Claim 1 or 2, wherein said resilient buoyant means comprises a tubular member rotatably fitted over said elongate core and a resilient buoyant body bonded to and disposed around said tubular member.

6. A buoy as claimed in Claim 5 comprising a flexible covering enclosing said resilient buoyant body and bonded to said tubular body.

7. A buoy as claimed in Claim 5 or 6, including a retainer ring disposed around said elongate core and a flange mounted on an end of said elongate core, said tubular body being secured between said retainer ring and said flange against axial displacement relative to said elongate core.

8. A buoy as claimed in claim 1 or 2, said resilient buoyant means comprising a pair of resilient buoyant bodies bonded to and disposed around said elongate core one on each side of said tube.

9. A buoy as claimed in Claim 8 comprising a pair of flexible coverings, each of which encloses a respective one of said pair of resilient buoyant bodies and is bonded to said elongate core.

10. A buoy as claimed in Claim 1 or 2, wherein said resilient buoyant means comprises a pair of tubular members rotatably fitted over said elongate core and disposed one on each side of said tube, and a pair of resilient buoyant bodies each bonded to and disposed around a respective one of said tubular members.

11. A buoy as claimed in claim 10 comprising for each resilient buoyant body a flexible covering bonded to said tubular member.

12. A buoy as claimed in Claim 4 or 9, wherein said buoyant (body(s) is/are in the form of a cylinder, said core has for each body a pair of annular flanges disposed therearound, and said covering(s) each having a pair of edge surfaces bonded to the peripheral surfaces of respective ones of said annular flanges, there being a pair of wire rings embedded in each of said covering(s) along said edge surfaces.

1 3. A buoy as claimed in any one of Claims 3 to 12, wherein said buoyant body is made of polyethylene foam.

1 4. A buoy as claimed in any one of claims 4,6,9,11 or 12, wherein said covering is of rubber or urethane.

1 5. A buoy as claimed in Claim 1 3 when appended to Claim 4,6,9,11 or 12, wherein said covering is of rubber or urethane.

1 6. A flexible anchor buoy substantially as herein described with reference to the drawings.