Note: Descriptions are shown in the official language in which they were submitted.
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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
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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the ~luke to be withdrawn from the bed.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withdrawn from the bed.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vessel can move to a position in which the anchor is withdrawn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
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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,
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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
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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.
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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
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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.
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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
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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
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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
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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
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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.
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