WO2015163758A1

WO2015163758A1 - Anchor

Info

Publication number: WO2015163758A1
Application number: PCT/NL2015/050232
Authority: WO
Inventors: Ferdinandus Joannes Gerardus JANSE
Original assignee: Stevlos B.V.
Priority date: 2014-04-22
Filing date: 2015-04-10
Publication date: 2015-10-29
Also published as: NL2012662B1; NL2012662A

Abstract

The invention relates to an anchor (1) comprising a fluke (10) and a shank (70) that is pivotally connected to the fluke, wherein the shank comprises two shank legs (71) that extend on the opposite site of the plane of symmetry of the shank and that diverge towards the fluke, and wherein the fluke comprises a central penetration body (31) between the shank legs and two outer penetration bodies (30) at the opposite sides outside the legs that impose the penetration direction to the anchor, wherein the penetration bodies are located in the plane of symmetry of the fluke, and two wings (50) that extend above and below the central penetration body and the outer penetration bodies to define a passage there between for the anchoring ground when penetrating in the penetration direction, wherein the fluke has an outline that defines a passage for the shank to swing the front side of the shank from one side of the plane of symmetry of the fluke to the other.

Description

Anchor

BACKGROUND

The invention relates to an anchor comprising a fluke and a shank that is pivotally connected to the fluke.

These type of anchors are known per se, such as from WO2013/133695. This anchor for heavy maritime or offshore objects, such as a drilling platform , has a shank having three legs to transfer the tremendous pulling forces to the fluke. There is a continuous need for anchors for heavy maritime applications that stably penetrate the anchoring ground.

It is an object of the present invention to provide an anchor for heavy maritime or offshore objects that stably penetrates the anchoring ground.

SUMMARY OF THE INVENTION

The invention provides an anchor comprising a fluke and a shank that is pivotally connected to the fluke, wherein the shank comprises two shank legs that extend on the opposite side of the plane of symmetry of the shank and that diverge towards the fluke, and wherein the fluke comprises a central penetration body between the shank legs and two outer penetration bodies at the opposite sides outside the legs that impose the penetration direction to the anchor, wherein the penetration bodies are located in the plane of symmetry of the fluke, and preferably two wings that extends above and below the central penetration body and the outer penetration bodies to define a passage there between for the anchoring ground when penetrating in the penetration direction, wherein the fluke has an outline that defines a passage for the shank to swing the front side of the shank from one side of the plane of symmetry of the fluke to the other.

When the anchor is vertically lowered to its anchoring ground, the shank can swing from one side to the other, whereby the anchor reaches its initial penetration position automatically. In this initial penetration position the fluke rests on the anchoring ground without being hampered by the shank. The wings give the penetration bodies the initial downward orientation that is needed to enter the anchoring ground. As the penetration bodies are present both between the shank legs and outside thereof, the penetration direction into the anchoring ground is optimally imposed to the fluke. This ensures a constant and stable penetration trajectory in the anchoring ground.

In an embodiment the fluke comprises two outer reinforcement plates that extend parallel to each other on the opposite sides of the plane of symmetry of the shank and parallel thereto, wherein the outer penetration bodies are connected against the outer sides of the reinforcement plates. The reinforcement plates form the connection between the outer penetration bodies and the shank, wherein the load is transferred parallel to the penetration direction of the anchor .

In an embodiment thereof the wings are connected to the outer reinforcement plates, whereby one form stable unity is obtained to withstands the penetration forces.

In an embodiment the fluke comprises two inner reinforcement plates that extend parallel to each other on the opposite sides of the plane of symmetry of the shank and parallel thereto, wherein the central penetration body extends between the inner reinforcement plates. The reinforcement plates form the connection between the central penetration body and the shank, wherein the load is transferred parallel to the penetration direction of the anchor .

In an embodiment thereof the wings are connected to the inner reinforcement plates, whereby one form stable unity is obtained to withstands the penetration forces.

In an embodiment the fluke comprises two outer reinforcement plates and two inner reinforcement plates that extend parallel to each other on the opposite sides of the plane of symmetry of the shank and parallel thereto, wherein the shank legs are inserted between the inner reinforcement plate and outer reinforcement plate on each side of the plane of symmetry of the shank.

In an embodiment thereof the shank legs are each pivotably connected to the fluke with a pivot pin between the outer reinforcement plate and inner reinforcement plate, wherein the shank legs comprise a first stop surface that engages a second stop surface of the fluke and wherein the first stop surface is located spaced apart and in the longitudinal direction of the shank legs behind the pivot pin. The first stop surface is spaced apart and behind the pivot pin, which is at the opposite side with respect to the end of the shank that is connected to the anchoring line. The momentum between the shank and the fluke is thereby converted to sheer forces at the pivot pin and the stop surfaces, which are well controlled.

In an embodiment thereof the fluke comprises two pairs of second stop surfaces that per pair are located at the opposite sides of the plane of symmetry of the fluke.

In an embodiment the second stop surface is formed by a stop pin that extends between the outer reinforcement plate and the inner reinforcement plate.

In an embodiment thereof the outer reinforcement plate and the inner reinforcement plate comprise multiple insert holes for selective insertion of the stop pin, wherein the outermost swing angle of the shank with respect to the fluke is defined by the selected insert hole. In an embodiment the stop pin comprises multiple second stop surfaces that are distributed around the circumference, wherein these second stop surfaces have different distances with respect to the center line or axis of rotation of the stop pin. The outermost angle is thereby set by rotation of the stop pin.

In an embodiment the outer penetration bodies each comprise a first penetration plate having its main plane in the plane of symmetry of the fluke. This first penetration plate directly imposes the penetration direction to the anchor .

In an embodiment the outer penetration bodies each comprise two second penetration plates that are oriented oblique to the plane of symmetry of the fluke, wherein the second penetration plates together form a hollow box that tapers in the direction away from the shank. The tapering hollow box provides stiffness to the fluke.

In a combined embodiment the first penetration plates define the outer edges of the fluke and the second penetration plates tapers towards the first penetration plates .

In an embodiment the central penetration body comprises a third penetration plate having its main plane in the plane of symmetry of the fluke. This third penetration plate directly imposes the penetration direction to the anchor .

In an embodiment the central penetration body comprises two fourth penetration plates that are oriented oblique to the plane of symmetry of the fluke, wherein the second penetration plates together form a hollow box that tapers in the forward penetration direction of the fluke. The tapering hollow box provides stiffness to the fluke.

In a combined embodiment the fourth penetration plates tapers towards the third penetration plate.

In an embodiment the wings are elongated and extend in their elongated direction parallel to the plane of symmetry of the fluke. The wings cover both the central penetration body and the outer penetration bodies.

In an embodiment thereof the wings comprise a first elongated wing plate that in its transverse direction extends oblique to the plane of symmetry of the fluke.

In an embodiment the wings comprise a second wing plate that extend from the outer extremity of the first wing plate to the first penetration plate. The first penetration plates and second penetration plates together form a framework around the penetration bodies to ensure a stable penetration path.

The various aspects and features described and shown in the specification can be applied, individually, wherever possible. These individual aspects, in particular the aspects and features described in the attached dependent claims, can be made subject of divisional patent applications .

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be elucidated on the basis of an exemplary embodiment shown in the attached drawings, in which :

Figures 1A and IB are an isometric front view and an isometric rear view of an embodiment of an anchor according to the invention;

Figure 2 is a top view of the anchor according to figures 1A and IB ;

Figure 3 is a front view of the anchor according to figures 1A and IB ; and

Figures 4A, 4B and 4C are an isometric view and two side views of the anchor according to figures 1A and IB , wherein some parts have been taken away to show the inner parts . DETAILED DESCRIPTION OF THE INVENTION

The figures show an anchor 1 according to an embodiment of the invention. The anchor 1 is intended for anchoring heavy maritime or offshore objects, such as a drilling platform in a subsea anchoring ground 2, for a long period of use that may last many years. The anchor 1 has a typical deadweight of at least one thousand kilos.

The anchor 1 comprises a fluke 10 and a shank 70 which with respect to the fluke 10 can incline obliquely forward and which at its end is provided with a shackle 90 with which the anchor 1 is connected to a mooring line or anchor line 4. The anchor 1 is substantially symmetrical with respect to its longitudinal plane of symmetry M. The anchor 1 is formed for in a forward direction of penetration P being introduced into the anchoring ground 2 substantially parallel to the longitudinal plane of symmetry M.

The fluke 10 is built up using steel plate members that are connected to each other by welding. As shown in figure 3, the fluke 10 has a transverse plane of symmetry N that extends transverse to the longitudinal plane of symmetry M of the entire anchor 1. The fluke 10 comprises two parallel and spaced apart wedge shaped outer reinforcement plates 12 that have a back side 13 and a slimmer front side 14 with a penetration tip 16 at the end. At the end of the back side 13 the reinforcement plates 12 are provided with hoisting eyes 15 on both sides of the transverse plane of symmetry N. The fluke 10 comprises two smaller inner reinforcement plates 20 at the facing inner sides of the outer reinforcement plates 12 and parallel thereto. The outer reinforcement plates 12 and the inner reinforcement plates all extend parallel to the longitudinal plane of symmetry M.

The fluke 10 comprises two outer penetration bodies 30 at the respective outer sides of the outer reinforcement plates 12 and one central penetration body 31 between the inner reinforcement plates 20. The outer penetration bodies 30 each comprise two first penetration plates 32 that form a hollow box. The first penetration plates 32 are straight and have a triangular outline. The base edges 33 of the first penetration plates 32 welded to the reinforcement plate 12, wherein the straight base edges 33 convert to the tip 16 of the reinforcement plate 12. The straight oblique outer edges 34 are welded to a second penetration plate 36 at the outside. The second penetration plates 36 are straight and have an elongated outline. The main plane thereof is situated in the transverse plane of symmetry N of the fluke 10. The second penetration plates 36 form the straight outer penetration edges 37 that are oriented obliquely to the longitudinal plane of symmetry M.

As best shown in figure IB the fluke 10 comprises an elongated back plate 40 with tapered ends 41 that are welded to the straight back edges 35 of the first penetration plates 32, and a straight middle section 42 that is welded to the back sides of the reinforcement plates 12 and the inner reinforcement plates 20. As best shown in figures 3 and 4A the central penetration body 31 of the fluke comprises two third penetration plates 43 that are straight and have a rectangular outline. The third penetration plates 43 are along one long side welded to the edges of the back plate 40 and along the short side welded to the inner reinforcement plates 20. The third penetration plates 43 are oriented obliquely to the transverse plane of symmetry N of the fluke 10, wherein they are along the opposite long side welded to a fourth penetration plate 44 to form a hollow box. The main plane of the fourth penetration plate 44 is situated in the transverse plane of symmetry N of the fluke 10. In the same plane N the fluke 10 comprises close to the tips 16 two elongated, triangular fifth penetration plates 45 that are welded to the facing inner sides of the outer reinforcement plates 12.

The fluke 10 comprises on both sides of the penetration bodies 30, 31 elongated first wing plates 50 that in their longitudinal direction extend parallel to the transverse plane of symmetry N. As best shown in figure 4C the first wing plates 50 extend in their transverse direction under an angle with the transverse plane of symmetry N. The notional extension of the main plane of the first wing plates 50 thereby intersects the transverse plane of symmetry N behind the tips 16. The first wing plates 50 comprises a rectangular middle section 52 and two tapered end sections 51 wherein the back edge 53 is straight. Right before the merger of the rectangular section 52 to the end sections 51 the first wing plates 50 are welded to the outer back sides 13 of the outer reinforcement plates 12 and to the coinciding edges of the inner reinforcement plates 20. The fluke 10 comprises four straight second wing plates 55 that are at their top welded to the outer edges of the first wing plates 50 and at their broader base welded to the back end of the second penetration plate 36.

The shank 70 is built up using steel plate members that are connected to each other by welding. The shank 70 comprises two shank legs 71 that are symmetric with respect to the longitudinal plane of symmetry M. The shank legs 71 each comprise a base section 72 that is inserted between the outer reinforcement plate 12 and the inner reinforcement plate 20, a tapering middle section 74 that is oriented under an angle with respect to the base section 72 via a deflection line 73, and an end eye 75 with a hole to connect with the shackle 90. The middle sections 74 are rigidly connected to each other with multiple parallel rods 76. The shank legs 71 are reinforced by additional reinforcement plates 80 against the base sections 72 having the same outline as the lower extremity of the base sections 72.

As best shown in figures 4A and 4B the base sections 72 of the shank legs 71 each comprise a hinge hole 77 that is aligned with hinge holes in the outer reinforcement plates 12 and the inner reinforcement plates 20. Through these hinge holes passes a hinge rod 78, whereby the shank 70 can hinge in direction A with respect to the fluke 10. As best shown in figure 2, the fluke 10 defines in its shape a passage to allows the shank 70 to freely hinge from one side of the transverse plane of symmetry N of the fluke 10 to the other side.

As best shown in figure 4B, the base sections 72 and the additional reinforcement plates 80 of the shank legs 71 comprises two converting stop edges 79 that bound a tongue 81, which with respect to the shackle 90 is located behind the hinge holes 77. The outer reinforcement plates 12 and the inner reinforcement plates 20 are provided with distributed pin holes 82 that are aligned between the plates, and abutment pins 83 that are selectively inserted and rotationally locked in the pin holes 82. The abutment pins 83 comprise one or more abutment edges 84 with different distance with respect to the center line of the pins 83. By selectively inserting and rotating the abutment pins 83 the outermost angle a of the shank 70 with respect to the fluke 10 can be adjusted. This outermost angle is related to the type of the anchoring ground 2, such as clay or sand.

As shown in figures 1A, IB and 4, the anchor 1 is vertically lowered onto the anchoring ground 2, wherein the fluke 10 rests on its lower first wing plate 50 and on its tips 16. The fluke 10 will always reach this initial penetration position as the fluke 10 can freely swivel in direction A between its outermost angles a from one side of the shank 70 to the other. The shank 70 can freely swivel downwards to temporarily rest on the anchoring ground 2. When the anchor 1 is pulled by the anchoring line 4 in direction R, the tips 16 are firstly urged into the anchoring ground 2, firstly followed by the fifth penetration plates 45 and the adjacent front end of the second penetration plates 36. The penetration plates 32, 36, 43, 44, 45, and the spaced apart wing plates 50 that at the back side of the fluke 10 define a passage with respect to the first penetration plates 32, the third penetration plates 43 and fourth penetration plate 44, together ensure a stable penetration course in the anchoring ground 2 in the penetration direction P.

The progressive pulling forces are transferred to the fluke 10 via the parallel outer reinforcement plates 12 and inner reinforcement plates 20 that form one unity with the fluke 10. The progressive momentum between the fluke 10 and the shank 70 with respect to the hinge rod 78 is transferred as sheer forces at the hinge rod 78 and the remote abutment pins 83.

It is to be understood that the above description is included to illustrate the operation of the preferred embodiments and is not meant to limit the scope of the invention. From the above discussion, many variations will be apparent to one skilled in the art that would yet be encompassed by the scope of the present invention.

Claims

C L A I M S

1. Anchor comprising a fluke and a shank that is pivotally connected to the fluke, wherein the shank comprises two shank legs that extend on the opposite side of the plane of symmetry of the shank and that diverge towards the fluke, and wherein the fluke comprises a central penetration body between the shank legs and two outer penetration bodies at the opposite sides outside the legs that impose the penetration direction to the anchor, wherein the penetration bodies are located in the plane of symmetry of the fluke, and two wings that extends above and below the central penetration body and the outer penetration bodies to define a passage there between for the anchoring ground when penetrating in the penetration direction, wherein the fluke has an outline that defines a passage for the shank to swing the front side of the shank from one side of the plane of symmetry of the fluke to the other.

2. Anchor according to claim 1, wherein the fluke comprises two outer reinforcement plates that extend parallel to each other on the opposite sides of the plane of symmetry of the shank and parallel thereto, wherein the outer penetration bodies are connected against the outer sides of the reinforcement plates.

3. Anchor according to claim 2, wherein the wings are connected to the outer reinforcement plates.

4. Anchor according to any one of the preceding claims, wherein the fluke comprises two inner reinforcement plates that extend parallel to each other on the opposite sides of the plane of symmetry of the shank and parallel thereto, wherein the central penetration body extends between the inner reinforcement plates.

5. Anchor according to claim 4, wherein the wings are connected to the inner reinforcement plates.

6. Anchor according to any one of the preceding claims, wherein the fluke comprises two outer reinforcement plates and two inner reinforcement plates that extend parallel to each other on the opposite sides of the plane of symmetry of the shank and parallel thereto, wherein the shank legs are inserted between the inner reinforcement plate and outer reinforcement plate on each side of the plane of symmetry of the shank.

7. Anchor according to claim 6, wherein the shank legs are each pivotably connected to the fluke with a pivot pin between the outer reinforcement plate and inner reinforcement plate, wherein the shank legs comprise a first stop surface that engages a second stop surface of the fluke and wherein the first stop surface is located spaced apart and in the longitudinal direction of the shank legs behind the pivot pin.

8. Anchor according to claim 7, wherein the fluke comprises two pairs of second stop surfaces that per pair are located at the opposite sides of the plane of symmetry of the fluke.

9. Anchor according to claim 7 or 8, wherein the second stop surface is formed by a stop pin that extends between the outer reinforcement plate and the inner reinforcement plate.

10. Anchor according to claim 9, wherein the outer reinforcement plate and the inner reinforcement plate comprise multiple insert holes for selective insertion of the stop pin, wherein the outermost swing angle of the shank with respect to the fluke is defined by the selected insert hole .

11. Anchor according to claim 9 or 10, wherein the stop pin comprises multiple second stop surfaces that are distributed around the circumference, wherein these second stop surfaces have different distances with respect to the center line or axis of rotation of the stop pin.

12. Anchor according to any one of the preceding claims, wherein the outer penetration bodies each comprise a first penetration plate having its main plane in the plane of symmetry of the fluke.

13. Anchor according to any one of the preceding claims, wherein the outer penetration bodies each comprise two second penetration plates that are oriented oblique to the plane of symmetry of the fluke, wherein the second penetration plates together form a hollow box that tapers in the direction away from the shank.

14. Anchor according to claims 12 and 13, wherein the first penetration plates define the outer edges of the fluke and the second penetration plates tapers towards the first penetration plates.

15. Anchor according to any one of the preceding claims, wherein the central penetration body comprises a third penetration plate having its main plane in the plane of symmetry of the fluke.

16. Anchor according to any one of the preceding claims, wherein the central penetration body comprises two fourth penetration plates that are oriented oblique to the plane of symmetry of the fluke, wherein the second penetration plates together form a hollow box that tapers in the forward penetration direction of the fluke.

17. Anchor according to claims 15 and 16, wherein the fourth penetration plates tapers towards the third penetration plate.

18. Anchor according to any one of the preceding claims, wherein the wings are elongated and extend in their elongated direction parallel to the plane of symmetry of the fluke .

19. Anchor according to claim 18, wherein the wings comprise a first elongated wing plate that in its transverse direction extends oblique to the plane of symmetry of the fluke.

20. Anchor according to claims 7 and 19, wherein the wings comprise a second wing plate that extend from the outer extremity of the first wing plate to the first penetration plate. o-o-o-o-o-o-o-o-

FG/HZ