CA1214077A - Anchor - Google Patents

Abstract

TITLE: ANCHOR

ABSTRACT
An anchor is provided with a fluke pivotally attached to a standard. A latch mechanism controls movement between the fluke and standard and is released upon application of a force in a predetermined direction. The standard is then free to pivot to a position in which the fluke and standard are aligned. This facilitates removal of the fluke from the sea bed. Sprags are provided on the rear of the fluke so that dragging of the anchor along the sea bed causes the fluke to rotate on the standard and be repositioned for engagement with the sea bed. Thus the anchor is able to reset upon the tide or wind changes. The latch includes a bar extending along the standard and having a follower running in a cam track on the fluke. The cam track is stepped to provide a stop that limits relative movement between the fluke and the standard until the direction of pull of the anchor rope moves the bar and lifts the follower clear of the stop. Reset is provided by a lost motion device that allows the bar to move over the stop.

Description

~1407~7 The present invention relates to anchors used to secure waterborne vessels relative to the ground.
It is of course well known to utilise 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 the 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 application of a vertical force to dislodge the material above the fluke. Should, however, the fluke snag on a solid object such as a rock on the bed then the application of such vertical force can cause damage to the anchor. When an anchor becomes snagged, it is therefore customary to manoeuver the vessel so that the cable exerts a force in a direction to disengage tne fluke from the object.
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 o~ a force to the standard, the fluke is positioned to enter the bed and secure ~214077 the vessel. H~wever, because of the stop which is necessary to ensure penetration of the anchor into the bed, it is not practical to manoeuver the vessel to a position which enables the ~luke to be withdrawn from the bed. Such a manoeuver would S 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 stop 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 from the sea bed.
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 provided an anchor comprising a standard, a fluke assembly pivotally connected to said standard, stop means opera~le between said standard and said fluke assembly to limit relative movement 121~077 therebetween to a predetermined 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, said latch means including reset means operable upon movement of said fluke assembly to a position within said predetermined range to enable said stop means.
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.
An embodiment of the invention will now be described by way of example only with reference to the accompanying 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 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, ~Z1~077 Figure 8 is a perspectiv~ view of a storage device for the anchor shown in Figure 1, Figure 9 is an enlarged view showing the arrangement of a cam track and follower used to control the relative movement of the fluke and standard, Figure 10 is a view on the line 10-10 of Figure 1, Figure 11 is a view on the line 11-11 of Figure 10, Figure 12 is a view on the line 12-12 of Figure 10.
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 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 links 26, 28 having an L-shaped cross section terminating in an annular boss 30 located at one end of each link. Each 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 links 26, 28 are each formed with an enlarged tang 33 that includes a bore 34 to receive studs 36 projecting from opposite sides of a block member 38.
The block member 3~ may therefore pivot relative to the links 26, 28 and is formed at its upper end with a clevis 40 to ~214077 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 pass through holes 50, S2 provided in the ears and block member respectively. Each of the ears 26 has an inner surface 54 which faces the outer suraface of the adjacent link 26 - 28. A counterbore 56 is formed on the inner surface 54 on a centre 57 that is displaced from the axis of rotation between the block member 38 and the links 26, 28 as defined by the stud 36 and the bores 34. A circular disc 58 is rotatably mounted in the bore 56 so as to be flush with the inner surface 54. The disc 58 has a radial slot 60 extending from the periphery of the disc 58 toward the centre 57.
A pair of slots 72, 74 are formed at opposite ends of each of the links 26, 28. These slots have similar overall ~ .
lengths and receive projecting pins 76, 78 attached to the 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 radial slot 60.
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 ~rom which the pin 20 projects. The end surface 82 is of generally diamond shape with the pin 20 positioned at its point of maximum width. The end surface 82 is formed with an upstanding circular boss 84 within which is formed a cam track 86 best seen in Figure 9 and defined by outer and inner walls 88, 90 respectively. The outer wall 88 is formed from a generally circular portion 88a centred on the pin 20 and terminating with chordal surfaces 88b. A curved portion 88c extends between the chordal surfaces 88b and has a constant curvature centred on the pin 20. The inner wall 90 is formed from an arcuate section 90a facing the curved portion 88c and subtended by radially extending portions 90b. The portions 90~ are interconnected by a pair of curved surfaces 90c that intersect at a cusp 90d. The centre of curvature of the surfaces 90c is eccentric to that of the circular portion 88a so that the width of the cam truck 86 increases progressively from the radial portions 90b to the cusp 90d. The inner and outer wall 88, 90 cooperate to define three regions in the cam track 86. A dwell region 92a is provided between the curved portion 88c and the arcuate portion 90a and allows the pin 78 to move along the track 86 as the fluke rotates relatives to the pin 20 without moving the link 80. A
transition region 92b is provided between the radial surfaces 90b and the chordal portions 88b with the radial portions 90b defining abutment surfaces for the pin 78 and limit relative movement between the fluke and standard until the slave link 80 is displaced relative to the fluke. An idle region 92c is ~z~40r7 provided between t~le curved portion 88a and curved surfaces 90c and allows relative rotation of the fluke and the standard.
The end surface 82 of the fluke 16, 18 merges at oneend 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 engagable with the surface in which the anchor is to be embedded.
To assemble the components of the anchor, the slave 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 positioned in the bores 34. The circular disc 58 is mounted in the counterbore 56 and the ears 46 are placed over the cheeks 44 with the ends of the pins 76 located within respective radial slots 60 the rivets 48 are then 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 2 and the pin 20 and fastener 2~ secured against axial movement by suitable fasteners. The flukes 16, 18 are then secured to one another for conjoint movement about the pin 20. During assembly the ends of the pins 78 are located in the cam track 86 and are held captive between the end surfaces 82.

121407q 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 radial portion 90b. 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 embedded 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 denoted ~.
Similarly, because of the depth of the radial portion 90b, tne block member 38 may rotate about the studs 36 through an angle B
without moving the pin 78 out of engagement with the end surface - 92. This movement accommodates the swell and tidal movements normally associated with a vessel at anchor.
Should the wind or current change, or it becomes 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 is engaged by the peripheral wall of the counterbore 56 and, by virtue of the eccentricity of the counterbore 56 is moved axially along the slot 72 to cause displacement of this slave 121~077 link 80. The disc rotates within the counterbore 56 by virtue of the engagement of the pin 76 in the slot 60 so that the slot 60 is always aligned with the direction of movement of the slave link 80. This displacement is sufficient to lift the pin 78 out of engagement with the radial portion 90b and onto the idle portion of the cam track 86 to allow the links 26, 28 to rotate about the pin 20 until they abut the stop member 22. As this occurs, the block member may reverse its rotation on the stud 36 and so allows relative movement between the slave link 80 and the links 26, 28. The radial slot 60 and progressively increasing width of the idle region 92c provides sufficient lost motion to accommodate the extreme relative positions of the block member 38 and links 26, 28 and so ensures movement of the standard without imposing large loads on the slave link. Upon abutment of the links 26, 28 with the stop member 22, the cable continues to rotate the block member 38 until the links 26, 28 and the block member are aligned.
Application or 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 diagramaticaly show 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 ~21~077 the vessel to drift, Such movement along the surface is opposed by the ribs 96 which, because of the configuration of the fluke assembly, are positioned at a greater angle of attack when the fluke asembly is extracted from the surfaces. 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 alon~ the inner curved surface 90c to axially displace the slave link 80 relative to the links 26, 28. This displacement is accommodated by movement along the slot 60 is always aligned with the pin 76. As the fluke assembly 14 continues to rotate, as shown in Figure 6, the pin 78 reaches the chordal surface 92 which upon further movement of the standard guides the pin 78 into the dwell region 92a and so acts to reset the pin 78 in a position to engage the radial surface 90a. 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 7~ is once again in a position to engage the radial surfaces 90a and 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 lZ1~07'7 maneouvered to a position which facilitates removal of the anchor should it be caught on an underwater object. The use of the releasable stop means constituted by the counterbore 56 the slave link 80 and the pin 78 operating within the cam track 86 ensures that the anchor will operate in a normal manner to provide adequate penetration of the surface. Further the mechanism is wholly contained within the structural components of the ancnor so that the possibility of debris entering and jamming the mechanism is reduced.
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 spray 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 112 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 12~ 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 ~214077 relative to the links.

To store the anchor 10 in the housing 110, the block member 3~ is rotated to a position generally 90 to the links 26, 28 to release the standard from the fluke assembly. The leading edges 94 of the fluke are then placed beneath the flaps 114 with the ribs g6 supported on the wall 112. A square stud 126 projects through an aperture between the s~op 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 (10)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An anchor comprising a standard, a fluke assembly pivotally connected to said standard, stop means operable between said standard and said fluke assembly to limit relative movement therebetween to a predetermined range and including a pair of opposed abutment members and latch means operable upon one of said abutment surfaces to displace it relative to the other of said abutment surfaces to disable said stop means and permit relative movement between said standard and said fluke assembly to exceed said predetermined range, said latch means including reset means operable upon movement of said fluke assembly to a position within said predetermined range to enable said stop means, said reset means including a cam surface operable upon said one abutment surface to move it positively into a position to be engaged by the other of said abutment surfaces as upon relative rotation between said fluke assembly and said standard.

2. An anchor according to claim 1 wherein said standard includes a clevis pivotally mounted for rotation about an axis perpendicular to the longitudinal axis of said standard and said latch means includes a cam member moveable with said clevis and operable to cause relative movement between said abutment members.

3. An anchor according to claim 2 wherein an elongate follower extends along said standard and is engageable at one end by said cam member and has said one abutment member formed at the other end.

4. An anchor according to claim 3 wherein lost motion is provided between said follower and said cam member.

5. An anchor according to claim 4 wherein said lost motion is provided by a guide member rotatably supported by said clevis and having a radial slot formed therein to allow movement of said follower along the longitudinal axis of said standard.

6. An anchor according to claim 5 wherein said latch means includes a pair of dependent ears located on opposite sides of said standard and each having a circular cam track formed therein and said follower includes a pair of lateral extensions passing in opposite directions through said standard and engaging respective ones of said cam surfaces.

7. An anchor according to claim 6 wherein a disc is rotatably supported in each of said cam tracks and includes a radial slot to permit movement of said extension away from said cam track.

8. An anchor according to claim 7 wherein said fluke assembly includes a pair of opposed surfaces between which said standard passes, each of said surfaces having a formation defining said cam surface and the other of said abutment members, said one abutment member being constituted by oppositely directed lateral extensions from said follower and each received with a respective one of said followers.

9. An anchor according to claim 8 wherein each formation includes a first portion located at a first radius from the pivot axis between said standard and fluke assembly, a second portion located at a second radius greater than said first radius from said pivot axis and a pair of spaced radial portions extending between said first and second portions to provide the other abutment member.

10. An anchor according to claim 9 wherein said cam surface extends between said spaced radial portions and includes a chordal portion to move said one abutment member from said second portion to said first portion and a radiused portion to allow movement of said one abutment member along said first portion.