EP0085090A1

EP0085090A1 - Anchor.

Info

Publication number: EP0085090A1
Application number: EP82902512A
Authority: EP
Inventors: Victor L Phillips; Peter J Fornasiero
Original assignee: VLP INVESTMENTS
Current assignee: Vlp Investments Ltd Te Hamilton Canada
Priority date: 1981-07-10
Filing date: 1982-07-12
Publication date: 1983-08-10
Also published as: EP0085090A4; CA1187345A; JPS58501903A; EP0085090B1; WO1983000126A1

Abstract

Une ancre (10) est pourvue d'une patte (14) fixée de manière pivotante à un montant (12). Un mécanisme de verrouillage (78, 88) commande le mouvement entre la patte (14) et le montant (12) et est libéré en appliquant une force dans une direction prédéterminée. Le montant (12) est alors libre de pivoter vers une position dans laquelle la patte et le montant sont alignés. Ceci facilite l'extraction de la patte ou aile (14) du fond marin. Des béquilles (96) sont prévues sur l'arrière de la patte de manière que la drague de l'ancre (10) sur le fond marin fait tourner la patte (14) sur le montant (12) et la remet en position pour s'engager dans le fond marin. Ainsi, l'ancre peut s'enfoncer de nouveau lors de changements de marée ou de vent.An anchor (10) is provided with a lug (14) pivotally attached to an upright (12). A locking mechanism (78, 88) controls movement between the tab (14) and the upright (12) and is released by applying force in a predetermined direction. The upright (12) is then free to pivot to a position in which the tab and the upright are aligned. This facilitates the extraction of the tab or wing (14) from the seabed. Crutches (96) are provided on the rear of the leg so that the anchor drag (10) on the seabed rotates the leg (14) on the upright (12) and returns it to position for s '' engage in the seabed. Thus, the anchor can sink again when the tide or wind changes.

Description

DESCRIPTION ANCHOR

TECHNICAL FIELD

The present invention relates to anchors used to locate waterborne vessels relative to the ground.

BACKGROUND ART

It is of course well known to utilize an anchor to secure a vessel in position to resist movement of the vessel under the influence of currents and wind. Such anchors are usually attached to the vessel by means of a flexible rope, cable or chain and are provided with flukes which engage the bed to resist movement of the vessel. The flukes are usually configured so that the application of the force through the cable will cause th fluke to penetrate the bed and securely hold the vessel. In order to withdraw the anchor from the bed, it is necessary to overcome the forces holding the fluke in position. This is usually accomplished by the applicati of a vertical force to dislodge the material above the fluke. Should, however, the fluke snag on a solid objec such as a rock on the bed then the application of such vertical force can cause daπage to the anchor. When an anchor becomes snagged, it is therefore customary to maneuver the vessel so that the cable exerts a force in a direction to disengage the fluke from the object.

- j E_ OMPI

SUBSTΣT' wro An anchor that has become popular in recent years is known as a Danforth anchor which generally comprises a spade-like fluke connected to -a standard. The fluke can pivot relative to the standard and stops are provided to limit the amount of movement. Thus the standard is held at an acute angle relative to the fluke so that upon application of a force to the standard, the fluke is positioned to enter the bed and secure the vessel. However, because of the stop, which is necessary to ensure penetration of the anchor into the bed, it is not practical to maneuver the vessel to a position which enables the fluke to be withdrawn from the bed. Such a maneuver would exert a very large force through the standard and into the fluke which could result in extensive damage to the anchor if the fluke is snagged on a rock or like obstacle.

A further problem associated with anchors which rely upon the application of a force to penetrate the bed is that reversal of the force will usually encourage the anchor to be withdrawn from the bed. Thus, if the tide or wind changes, the vessel can move to a position in which the anchor is withdrawn from its location. This is obviously undesirable and is another reason for providing a positive stop on the Danforth type anchor. With such positive stop, the reversal of the force will tend to act through the top to try and pull the fluke vertically from the sea bed. This does offer some resistance to movement. However, as previously mentioned, the provision of such a stop does limit the extraction of the anchor from a snag or fron the sea bed.

DISCLOSURE OF THE INVENTION

It is therefore an object of the present invention to provide an anchor in which the above disadvantages are obviated or mitigated.

According to the present invention there is provide an anchor having a standard for connection to a flexible

OMPI fastening device and a fluke assembly pivotally connected to said standard for movement about a pivot axis, said fluke having a leading edge for engagement with and penetration of a surface to which said anchor is to be secured, said fluke assembly including sprag means at a location spaced from said leading edge to oppose movement to extract said fluke assembly from sai surface whereby upon application of a force by said fastening means to withdraw said leading edge from said surface, said sprag means engages said surface and rotates said fluke assembly relative to said standard to a position in which continued application of said force causes said leading edge to penetrate said surface. Preferably stop means are provided to limit pivotal movement about said axis, said stop means being yieldable and releasing upon application of said force in said direction to withdraw said leading edge to permit said standard to pivot to a position substantially aligned with the direction of said force to enable withdrawal of said fluke.

The provision of the sprag means enables the standard to be pivotally connected to the fluke in a manner that permits it to be aligned with the fluke to enable withdrawal from the sea bed. Should the with¬ drawal of the fluke be accidental, for example be caused by a change in wind or current, then the sprag will engage the sea bed and reset the anchor to resecure the vessel. In the preferred embodiment, the releasable stop means facilitates setting of the anchor in the

' conventional manner but does not inhibit the release or resetting of the anchor when necessary.

BRIEF DESCRIPTION OP THE DRAWINGS

An embodiment of the invention will not be describe by way of example only with reference to the accompanyin drawings in which

FIGURE 1 is a perspective view of an anchor,

FIGURE 2 is an exploded perspective view of the anchor shown in Figure 1, FIGURE 3 is a section on the line 3-3 of Figure 1,

FIGURE 4 is a view similar to Figure 3 showing the release of the standard to a position to withdraw the anchor,

FIGURE 5 is a view similar to Figure 3 showing the standard in a position to withdraw the anchor,

FIGURE 6 is a view similar to Figure 3 showing the anchor resetting.

FIGURE 7 is a view similar to Figure 3 showing the continued resetting of the anchor with the anchor shown in its reset position in chain dot lines,

FIGURE 8 is a perspective view of a storage device for the anchor shown in Figure 1.

BEST MODE

Referring now to the drawings and in particular to Figures 1 and 2, an anchor generally designated 10 comprises a standard 12 and a fluke assembly 14. The fluke assembly 14 comprises a pair of similar flukes 16, 18 which are connected by a pin 20. A stop member 22 is integrally formed with each of the flukes 16, 18

OMPI at a location spaced from the pin 20. A fastener 24 extends between the two stop members 22 and is secured by a cotter pin or like member to hold the two flukes together. The standard 12 comprises a pair of parallel links 26, 28 which are held in spaced relationship by means o annular bosses 30 located at one end of each link. Eac boss 30 includes a bore 32 which receives the pin 20 to pivotally connect the standard 12 to the fluke assembly 14.

The opposite end of the lines 26, 28 are each forme with a bore 34 to receive studs 36 projecting from opposite sides of a block member 38. The block member 38 may therefore pivot relative to the links 26, 28 and is formed at its upper end with a clevis 40 to receive a flexible fastener such as a cable 42. The block member is also formed with a pair of cheeks 44 intermediate the clevis 40 and the studs 36. The cheeks 44 project outwardly to a position generally parallel with the outer face of the links 26, 28 and an ear 46 is attached to each of the cheeks 44 by means of rivets 48 which pas through holes 50, 52 provided in the ears and block member respectively. Each of the ears 46 has an inner surface 54 which faces the outer surface of the adjacent link 26-28. A cam track 56 is formed on the inner surface 54. The cam track 56 is of constant curvature and is eccentric to the axis of rotation between the block member 38 and the links 26, 28 defined by the stud 36 and the bores 34. The inner surface 54 is also provided with a keyhole shaped recess 58 comprising a circular portion 60 and a generally rectangular portion 62. The circular portion 60 is centred on the rotational axis between the block member 38 and the links 26, 28 and accommodates an elasto eric block 64. The block 64 includes a projecting portion 66 which is accommodated in the rectangular portion 62 and is retained by means of cooperating shoulders 68 provided on the rectangular portion 62 and the projecting portion

OMPI 66. The block 64 is shaped so that its end surface 70 is flush with the walls defining the cam track 56. -A pair of slots 72, 74 are ϋormed at opposite ends of each of the links 26, 28. These slots have similar overall lengths and receive projecting pins 76, 78 attached to opposite ends of a slave link 80. The spacing of the pins 76, 78 corresponds to the mean spacing between the slots 72, 74 so that the slave link 80 is free to slide relative to the links 26, 28 by an amount equal to the overall length of the slots 72, 74. The slave link 80 is positioned between the links 26, 28 and the pin 76 adjacent the block member 38 projects beyond the outer surface of the links 26, 28 and into the cam track 56. Similarly the pin 78 adjacent the boss 30 projects beyond the outer surface of links 26, 28 toward the flukes 16, 18.

Each of the flukes 14, 16 has an end surface 82 from which the pin 20 projects. The end surface 82 is generally diamond shape with the pin 20 positioned at its point of maximum width. The end surface 82 is formed with a pair of kidney shaped protuberances 84, 86 which partially encompass the boss 30. Each protuberance is defined by inner and outer curved surfaces 88, 90 respectively which smoothly merge at one extreme and are interconnected by an abutment surface 92 at the other extreme. The abutment surface 92 is positioned so that the pin 78 engages it when the slave link 80 is at one extreme of its travel but is lifted clear of the abutment surface when the slave link is at the other end of its travel.

The end surface 82 of the fluke 16, 18 merges at one end with a leading edge 94 of the fluke. This edge is chamfered to provide a penetrating edge of the generally planar body of the fluke. The opposite end of the end surface 82 merges with a pair of flared ribs 96, 98 interconnected by a wall 100 upon which the stop member 22 is mounted. The ribs 96 diverge from the general plane of the fluke 16, 18 and define a sprag member engageable with the surface in which the anchor is to be embedded.

To assemble the components ^"of the anchor, the slav link 80 and block member 38 are positioned between the links 26, 28 with the pins 76, 78 located in the slots 72, 74 respectively and the studs 36 are positioned in the bores 34. The annular elastomeric ring 64 is positioned within the circular recess 60 of each ear 46 and the slug 66 positioned in the rectangular portion 62 The ears 46 are placed over the cheeks 44 with the ends of the pins 76 located within the cam track 56 and the rivets 48 driven through the holes 50, 52 and peened to secure the ears to the block member.

The pin 20 is then fastened in the fluke 16 and passed through the bores 30 and bosses 32 into the fluke 18. The fastener 24 is also passed through the stop members 22 and the pin 20 and fastener 24 secured agains axial movement by suitable fasteners. The flukes 16, 18 are then secured to one another for conjoint movement about the pin 20. The ends of the pins 78 are located adjacent the end surface 82 and between the abutment surfaces 92 of the protuberances 84.

In operation, the cable 42 is attached to the clevis 40 and the anchor 10 lowered to the surface to which the vessel is to be secured. The standard 12 is free to pivot on the pin 20 over a range of movement determined by the spacing of the abutment surfaces 92. Upon engagement of the fluke assembly 14 with the surface, the leading edge 94 is positioned to penetrate the surface. The application of a force through the cable 42 causes the standard to rotate on the pin 20 until the pin 76 abuts the end surface 92. Further application of a force from the cable in the general direction of extension of the standard will force the leading edge 94 into the surface until it is firmly imbedded and resists movement of the vessel.

In this position, which is indicated in Figure 3, the links 26, 28 may rotate on the pin through an angle

OMPI ^" denoted A. Similarly, because of the depth of the end surface 92, the block member 58 may rotate about the studs 36 through an angle B without moving the pin 78 at an engagement with the end surface 92. This ove- ment accommodates the swell and tidal movements normally associated with a vessel at anchor.

Should the wind or current change, or it be necessary to withdraw the anchor, the angle of the cable 42 would change to that shown in Figure 4. In this position, the block member pivots about the links 36 on the axis defined by the studs 36 and carries the ears 46 with it. The pin 76 which is captive within the slot 72 moves along the cam track 56 and, by virtue of the eccentricity of the cam track 56 is moved axially along the slot 72. This axial movement is sufficient to lift the pin 78 out of engagement with the end surface 92 and allows the links 26, 28 to rotate about the pin 20 until they abut the stop member 22. As this occurs, the block member reverses its rotation on the stud 36. The curve of the outer curved surface 90 is therefore chosen such that the distance between the pin in the cam track 56 and the point of contact of the pin 78 on the outer curve surface 90 is constant. Upon abutment of the links 26, 28 with the stop member 22, th cable continues to rotate the block member 38 until the links 26, 28 and the block member are aligned. In this position, the pin 76 is in engagement with the end surface 70 of the block 64. Application of a force through the cable 42 in this position will extract the fluke assembly from the surface so that if it is located beneath a stone as diagraπatically shown in Figure 5, extraction can be made without great difficulty. If it is desired to weigh the anchor, then a vertical force is applied to the anchor through the cable 42 after it has been released from the surface and the anchor lifted aboard the vessel. If, however, the change in direction of the cable 42 is caused by a wind shift or current shift, then the cable will continue to move the anchor assembly along the surface allowing the vessel to drift.

- Such movement along the sύ-r-face is opposed by the ribs 96 which, because of the configuration of the flu assembly, are positioned at a greater angle of attack when the fluke assembly is extracted from the surface. The ribs 96 therefore dig into the surface along which the anchor is being drawn and tend to rotate the fluke assembly about the pin 20 relative to the standard 12. As the standard 12 rotates, the pin 78 rides along the outer curved surface to axially displace the slave link 80 relative to the links 26, 28. This displacemen is accommodated by compression of the elasto eric block 64. As the fluke assembly 14 continues to rotate, as shown in Figure 6, the pin 78 reaches the abutment surface 92 and the elastomeric block biases the slave link 80 back to a position in which the pin 76 is aligned with the cam track 56. The block member 38 is then free to rotate relative to the links 26, 28 and the cable continues to pull the anchor 12 until the fluke assembly passes its balance point and falls into abutment with the surface. In this position, the pin 78 is once again in a position to limit movement of the fluke assembly relative to the standard 12 so that continued movement of the fluke assembly along the surface causes the leading edge 94 to penetrate the surface and provide a secure location for the anchor 10

It may be seen therefore that the anchor assembly operates to reset itself upon a reverse of direction of the applied load to the anchor and also enables the vessel to be maneuvered to a position which facilitates removal of the anchor should it be caught on an under¬ water object. The use of the releasable stop means constituted by the cam track 56, the slave link 80 and the pin 78 operating with the abutment surface 92 ensures that the anchor will operate in a normal manner to provide adequate penetration of the surface.

Alternative arrangements of a releasable stop member are of course possible within the scope of the present invention. For example the slave link 80 may be pivoted directly to the block member 38 rather than constrained from movement within the links 26, 28 by the slot 72. While such an arrangement is possible, the construction illustrated is preferred to inhibit the possibility of debris entering between the slave link and the links 26, 28 as the block member rotates and thereby holding the anchor in the unlatched position.

It should be noted that the generally bulbous nature of the fluke assembly adjacent the pin 20 assists not only in setting the leading edge 94 at the correct angle of attack, but also assists in increase in the angle attack of the sprag members defined by the ribs 96.

The ability of the standard assembly to pivot over a full range of movement relative to the fluke assembly also facilitates storage of the anchor onboard the vessel. A suitable storage arrangement is shown in Figure 8 where the anchor 10 is accommodated in a housing 110. The housing 110 is delimited by generally rhombic shaped upstanding wall 112 with a pair of flaps 114 extending from the wall 122 toward the centre of the housing 110. A pair of spaced parallel walls

116 terminate the flaps 114 and provide a channel into which the standard of the anchor may be placed. A track 118 is cut into each of the walls 116 and comprises a straight portion 120 and a curved portion 122. Each of the ears 46 is provided with a stud 124 displaced from the axis of rotation of the block member relative to the links.

To store the anchor 10 in the housing 110, the block member 38 is rotated to a position generally 90° to the links 26, 28 to release the standard from the fluke assembly. The leading edges 94 the fluke are then placed beneath the flaps 114 with the ribs 96 supported on the wall 112. A square stud 126 projects through an aperture between the stop member 22 and the pin 20 to accommodate a linch pin or similar device to hold the flukes in position. The stud 124 is then positioned adjacent ^'the straight portion 120 and the links 26, 28 pivoted about the pin until the stud 124 is at the junction of straight and curved portions 121, 122. The block member 38 is then rotated so that the stud 124 passes down the curved portion 122 until the block member and links are aligned. The anchor 10 is therefore held firmly within the housing 110 with the leading edge 94 of the flukes protected beneath the flaps 114. Release of the anchor is relatively simple, merely requiring the rotation of the block member to release the stud from the curved portion and then rotation of the links about the pin 20.

If preferred, the lower end of the anchor may be supported on a pair of wedge blocks 128 shown in dotted lines in Figure 8 to avoid the use of the linch pin to hold the fluke assembly in position.

Claims

WE CLAIM :

1. An anchor having a standard for connection to a flexible fastening device and a fluke assembly pivotall connected to said standard for movement about a pivot axis, said fluke assembly having a leading edge for engagement with and penetration of a surface to which said anchor is to be secured and including sprag means at a location spaced from said leading edge to oppose movement to extract said fluke assembly from said surface whereby upon application of a force by said fastening means to withdraw said leading edge from said surface, said sprag means engages said surface and rotates said fluke assembly relative to said standard to a position in which continued application of said force causes said leading edge to penetrate said surface.

2. An anchor according to claim 1 wherein stop means are provided to limit piλ^*otal movement about said axis, said stop means being yieldable and releasing upon application of said force in said direction to withdraw said leading edge to permit said standard to pivot to a position substantially aligned with the direction of said force to enable withdrawal of said fluke.

3. An anchor according to claim 2 wherein said standard encompasses a pair of links pivotally connected for relative movement about an axis substantially parallel to said pivot axis and said stop means is operably connected to said links so that relative rotation of said links beyond a predetermined position causes release of said stop means.

4. An anchor according to claim 1 wherein said stop means includes a pair of abutment members, and rotation of said links beyond said predetermined position withdraws one of said abutment members from engagement with the other.

5. An anchor according to claim 4 wherein said links are connected to said one abutment member by means of a lost motion device.^"-

6. An anchor according to claim 5 wherein said lost motion device is a resilient member acting to bias said one abutment member to a position in which it engages the other of said abutment.

7. An anchor according to claim 4 including a cam member attached to one of said links for rotation therewith and a follower attached to the other of said links, relative rotation of said links inducing displacement of said follower to withdraw said one abutment member.

8. An anchor according to claim 7 wherein spring means are provided to bias said one abutment member into a position in which it abuts the other of said abutment members.

9. An anchor comprising a standard, a fluke assembly and pivot means connecting said standard and fluke assembly, said fluke assembly including a pair of flukes located on opposite sides of said standard and each having a leading edge projecting to one side of said pivot means and a sprag member projecting in a direction opposite to said leading edge and located on the opposite side of said pivot means to said leading edge, whereby movement of said fluke assembly in one direction causes engagement and penetration of said leading edge with a surface and movement in a direction opposite said one direction causes engagement of said sprag member with said surface to induce rotation of said fluke assembly relative to said standard.

10. An anchor according to claim 9 wherein said sprag member includes a pair of divergent ribs .

11. An anchor according to claim 10 wherein said fluke assembly is shaped to increase the angle between

5 said surface and one of said ribs abutting said surface upon extraction of said leading edge from said surface.

12. An anchor according to claim 11 including a stop member located between said fluke assembly and 0 said standard to limit relative movement therebetween and latch means operable to disable said stop means and permit movement of said standard to a position to apply a force in a direction opposite to said one direction.

13. An anchor according to claim 12 wherein said 5 stop means includes a pair of abutment members and said latch means includes link means operable to move one of said abutment members out of engagement with the other of said abutment members to disable said stop means.

14. An anchor according to claim 13 wherein said 0 latch means are responsive to the direction of application of load to said standard to disable said stop means.

15. An anchor according to claim 14 wherein said standard is formed from first and second link means -5 pivotally connected to one another for relative rotation said first link means being connected to said fluke assembly and said second link means being connectable to a flexible member attached to a vessel, said latch means being connected to said second link means so as 0 to disable said stop means upon rotation of said second link means relative to said first link means beyond a predetermined point.

16. An anchor according to claim 15 wherein said latch means includes a cam member attached to said second link means and a follower~operably connected to said stop means whereby rotation of said second link means causes displacement of said follower to disable said stop means.

17. An anchor according to claim 16 wherein said follower is slidably supported on said first link means and is connected to one of said abutment members.

18. An anchor according to claim 17 including a lost motion device between said cam and said follower to permit return of said abutment members to a latched condition.

19. An anchor comprising a standard, a fluke assembly pivotally connected to said standard, stop mea operable between said standard and said fluke assembly to limit relative movement therebetween to a pre¬ determined range and latch means operable upon said stop means to disable said stop means and permit relative movement between said standard and said fluke assembly to exceed said predetermined range.

20. An anchor according to claim 19 wherein said latch means is responsive to the direction of force applied to said standard and operable to disable said stop means upon said direction exceeding a pre¬ determined limit.

21. An anchor according to claim 20 wherein said stop means includes a pair of abutment members which are located in a position to abut when said direction of applied force is within said predetermined limit.

22. An anchor according to claim 21 wherein said latch means is operable to displace one of said

WIPO abutment members when said direction of applied force exceeds said predetermined limit.

23. An anchor according to claim 22 wherein said latch means includes a first member displaceable upon variation of the direction of applied force.

24. An anchor according to claim 23 wherein said first member is connected to said one abutment member to induce movement thereof upon displacement of said first member.

25. An anchor according to claim 24 wherein said first member includes a cam surface and a follower is connected between said cam surface and said one abutment member.

26. An anchor according to claim 25 wherein said standard is formed from a pair of pivotally inter¬ connected links, a first of which is connected to said fluke assembly and a second of which is connectible to a vessel, said first member being fixed to said first link for rotation therewith.

27. An anchor according to claim 26 wherein said follower is supported by said second link and is slidable relative thereto upon rotation between said first and second links.

^'28. An anchor according to claim 27 including a lost motion device operable between said cam surface and said follower to enable said one abutment member to move past the other of said abutment members upon return of said direction of applied force to within said predetermined limit regardless of the relative disposition of said first and second links.

29. An anchor according to claim 28 wherein said other abutment member includes ramp means to lift said one member upon return of said standard to within said predetermined range.

30. An anchor according to claim 29 wherein said lost motion device includes biasing means operable to bias said one abutment member toward said ramp means.