GB2156755A - Anchors - Google Patents

Abstract

An anchor comprising an elongate shank 12, and a plurality of elongate, generally flat flukes 19-22, each fluke having an end pivotally attached to the shank wherein the flukes are individually freely movable about their respective pivot point to pivot from a position in which they lie generally parallel to the shank to a position in which they extend obliquely outwardly from the shank. Removable weights 29 are provided in the hollow shank. <IMAGE>

Description

SPECIFICATION Anchors The present invention relates to anchors and particularly, but not exclusively, to anchors for small boats.

Conventional anchors are provided with rigid flukes which are barbed for catching in rocks or becoming entrenched in sand or other soft material on the sea-bed so as to anchor a vessel. These rigid flukes are a safety hazard in many respects. If they lodge between underwater rocks, the anchor rope may have to be cut and the anchor abandoned. If no implement is available for cutting the anchor rope and the tide rises, the boat may be dragged underwater by the anchor thus endangering the lives of the crew. The anchor may also have to be abandoned if the flukes catch in underwater electric cables, which is a further danger in itself, or in ropes of other boats.Rigid flukes on an anchor are also a hazard in rough sea because they can damage the hull of the boat when the anchor is being drawn up and the barbs on the flukes have been known to cause injury to people on deck, especially children. Anchors with rigid flukes are also bulky to store.

It is known to avoid some of these problems by providing an anchor having adjustable flukes and an adjustable locking mechanism associated with the flukes. However, once the flukes are locked in position the anchor has many of the disadvantages of a conventional rigid anchor.

According to the present invention, there is provided an anchor comprising an elongate shank, and a plurality of elongate, generally flat flukes, each fluke having an end pivotally attached to the shank whereby the flukes are individually freely movable about their pivot point to pivot from a position in which they lie generally parallel to the shank to a position in which they extend obliquely outwardly from the shank.

An advantage of an anchor according to the present invention is that it is much safer to use because the flukes are independently collapsible around the shank of the anchor. This feature renders the anchor relatively easily dislodgable from underwater rocks and other obstructions. If an anchor according to the present invention becomes lodged underwater, for example in rocks, moving the boat back towards the anchor slackens the pull on the anchor thus allowing the fluke or flukes which are trapped to pivot relative to the shank so as to become free from the rocks.

The collapsible nature of the flukes also ensures that the anchor is not an obstruction when laying on deck and is much more safe to use on deck and also reduces the chance of damage to the hull of the boat whilst handling the anchor in rough weather. Furthermore, the anchor is compact thus facilitating storage.

The maximum pivot angle of the flukes must be such that one or more of the flukes will become embedded as the anchor is dragged along the sea-bed.

Preferably, the flukes are able to pivot up to 40 from the shank of the anchor. In a preferred embodiment, the maximum pivot angle is approximately 30 , which pivot angle has been found to be particularly effective in use.

The shank of the anchor may be hollow for accommodating weights and may be designed so that the weights are removable.

A particular embodiment of the present invention will now be described by way of example, with reference to the accompanying drawings in which: Figure 1 is a perspective exploded fragmentary view of an anchor according to the present invention; Figure 2 is a diagrammatic side view on a reduced scale showing one of the flukes pivoted away from the core of the anchor; Figure 3 and Figure 4 are diagrammatic plan and side views respectively of a separate fluke; Figure 5 and Figure 6 are diagrammatic plan and side views respectively of a stock.

Referring to Figure 1 and Figure 2, an anchor of mild steel is indicated generally at 10 and comprises a tubular square section shank 1 2 formed from mild steel and having open front and rear ends 1 3 and 14 respectively. The front end 1 3 is formed with four rectangular slots 1 5 to 1 8 each of which extends a short distance into the end of one of the flat walls of the shank 1 2. Four identical generally flat flukes 1 9 to 22 (flukes 1 9 and 20 are shown in Figure 1) are pivotally mounted in the slots 1 5 to 1 8 in a manner to be described in more detail below.

A bolt 23 has a screw threaded end 24 and a rounded head 25 adjacent which is a generally square keying section 25a. The bolt 23 is passable through a cap 26 and is engageable in a stock 27 provided with a screw threaded bore 28. A plurality of square section weights 29 are positioned inside the tubular shank 1 2 and have circular apertures 30 so that they are slidably mountable on the bolt 23.

The weights 29 are of a size such that they are freely slidable along the length of the shank 1 2 while allowing very little lateral movement of the weights 29 within the core 12.

The cap 26 has a square aperture 31 and bevelled edges 32 to 35. The cap 26 is provided with a marginal square lip (not visible in Figure 1) configured so that it is a push-fit in the front end 1 3 of the shank 12.

Referring to Figures 3 and 4, the fluke 1 9 has a generally flat body 36 having a pointed head portion 37 and a forked tail portion 38.

The tail portion is bent upwardly relative to the remainder of the body portion 36 (see Figure 4) and terminates in a barbed portion 39. An oval plate 40 is welded to the underside of the body portion 36 so as to lie in a plane perpendicular to the body portion centrally of the width of the body portion but near the head portion 37. The oval plate 40 has an aperture in which a cross pin 41 is fixed. The pin 41 is of toughened steel and has a central bore communicating with a longitudinal slit (not shown) to permit deformation of the pin 41. In a relaxed condition, the diameter of the pin 41 is slightly greater than the diameter of the aperture in the oval plate 40. The slight deformability of the pin 41 allows it to be forced into the aperture in the oval plate 40 so as to be securely fixed therein.The spacing between the aperture in the plate 40 in which the pin 41 is fixed is large enough to accommodate the thickness of the walls of the hollow shank 1 2 adjacent the slots 15 to 18.

To mount the fluke 1 9 on the shank 12, the plate 40 is slid longitudinally into one of the slots 1 5 to 18 so that the pin 41 abuts the interior wall of the shank 1 2 and prevents the fluke 1 9 from being pulled laterally out of the slot. The thickness of the plate 40 is such that there is a small clearance between the plate and the slot. Sideways twisting of the plate is thus restricted, but pivotal movement of the fluke 19 about the pin 41 is allowed.

The plate 40 extends almost the entire length of the slot but a small amount of play (approximately 1/2 cm) for longitudinal sliding of the plate 40 in the slot is allowed. The remaining three flukes 20,21 and 22 are mounted in a similar manner and are prevented from sliding forwardly out of the slots 1 5 to 18 by the cap 26 when it is in place in the front end 1 3 of the shank 12.

Referring to Figures 5 and 6, the stock 27 is of square section and has the screw threaded bore 28 at one end 42 thereof. The other end 43 of the stock 28 terminates in an end portion 45 of reduced width thus defining a shoulder 44 and comprising a bore 46 enabling a chain (not shown) to be attached to the stock 27. A bush 47 (see Figure 1) of low density polythene is provided which is a pushfit over the bored end 43 of the stock 27. The bush is of sguare section and has a forward section 48, which is a clearance fit in the end of the hollow shank 12, and a rear flange 49 providing a shoulder 50 which abuts the edge of the shank 12 and which acts to prevent rotation of the stock 27 relative to the shank 12. Four flattened ribs 51-54 are provided on the interior of the bush 47 which make sliding contact with the stock 27.

To assemble the anchor 10, the four flukes 1 9 to 22 are mounted in the slots 1 5 to 18 as described above. The weights 29 are slid into the hollow shank 12 from the front end 1 3 and the stock 27 is positioned with the bore 28 behind the rearmost of the weights 29. The cap 26 is then pushed into the front end 1 3 of the shank 12 and the bolt 23 is slid through the square aperture 31 in the cap 26, through the circular apertures 33 in the weights 29 until the keying section 25a locates in the aperture 31 to prevent rotation of the bolt 23. The bore 28 of the stock 27 is then screwed onto the screw threaded end 24 of the bolt 23.The bush 47 is then slid over the end 43 of the stock 27 towards the rear end 14 of the shank 1 2 until the forward section 48 of the bush 47 locates inside the rear end 14 of the shank 1 2 and the shoulder 50 abuts the end edge of the rear end 14 of the shank 1 2 thereby preventing rotation of the stock 27 relative to the shank 1 2. A chain (not shown) is then secured in the bore 46 at end 43 of the stock 27 and the anchor 10 is ready for use.

To remove or to add weights 29 as desired, the bush 47 is slid back over the stock 27 and the stock 27 is then unscrewed from the bolt 23. Weights 29 are then removed or added and the stock again screwed onto the bolt 23 and the bush 47 replaced to prevent rotation of the stock 27 relative to the shank 12.

The anchor 10 described above has a shank 1 2 of length approximately 8" (20 centimetres) and an overall length when the stock 27 is attached of approximately 1 5" (38 centimetres) and is intended for use with small boats, for example of 20 feet (6.1 metres) in length. The weights 29 together weigh only approximately 21 bus (1.9kgs) and act as a washer between the bolt 23 and the stock 27.

When the anchor 10 is assembled, each of the flukes 19-22 is independently pivotable relative to the shank 1 2 about its pin 41. The maximum pivot angle is approximately 30' (see Figure 2). When the anchor 10 is held by the user with the front end 1 3 of the shank pointing downwardly, all four of the flukes 19-22 pivot outwardly under the force of gravity until the pointed head portions 37 abut to form a pyramid so that further outward pivoting is prevented. However, a single one of the flukes 19-22 can be pivoted outwardly to a slightly greater angle than when all four flukes pivot outwardly together owing to the limited longitudinal slidability of the plate 40 on the respective fluke in one of the slots 15 to 18 in the shank 12. The pivoting movement of a single fluke 19-22 is restricted by abutment of the inner surface of the pointed head portion 37 on the respective bevelled edge 32 to 35 of the cap 26. By sliding the plate 40 forwardly as far as possible in the slot 1 5 to 18 in the front end 1 3 of the shank 12, that is, until it abuts the inside of the cap 26, the pivot axis defined by the pin 41 is moved forwardly thus enabling the fluke to be pivoted outwardly through a slightly greater angle before the inner surface of the pointed head portion 37 of the fluke abuts a bevelled edge 32 to 35 of the cap 26 to prevent further pivoting. The advantages of this feature in use will be described below.

In use, the anchor 10 is attached to a chain, the length of whichis chosen according to the particular conditions of use and the preference of the user. The chain provides most of the weight needed to anchor a small vessel. It is usual practice to attach the free end of the chain to a rope and to attach the rope to the boat. To anchor the vessel, the anchor 10 is thrown into the water and dragged by the boat along the sea-bed. The weight of the anchor chain ensures that the anchor 10 lies flat on the sea-bed. The barbed end 39 on each of the flukes 19-22 is adapted to aid embedding of the fluke on the sea-bed and, as the anchor 10 is being dragged along, the bottom-most fluke starts to pivot outwardly from the shank 1 2 as the barbed end 39 becomes embedded in soft material on the sea-bed.The resultant pull on the anchor 10 urges the plate 40 of the bottom-most fluke to slide forwardly in its slot 1 5 to 1 8 thereby increasing the maximum pivot angle of that fluke as described above to aid embedding of the fluke. Alternatively, one or more of the flukes 19-22 may lodge between underwater rocks.

When the anchor 10 is engaged on the seabed, the pull of the boat imposes a levering force about the pivot axis of the embedded fluke or flukes. When only one of the flukes is engaged on the sea-bed, further pivoting of the fluke is prevented by abutment of the inner face of the pointed head portion 37 against a bevelled edge 32-35 of the cap 26.

When two or more of the flukes 19-22 are involved, further pivoting of the flukes is prevented by abutment of the head portions 37 of the respective flukes. Tests have shown that the anchor 10 described above can withstand substantial pulling forces and that the angle provides a secure grip on the sea-bed to anchor a vessel. In practice, the boat to be anchored is set so as to ensure that the tide always pulls the boat away from the anchor thereby guarding against accidential dislodgement of the anchor.

When it is desired to recover the anchor from the sea-bed, the boat is moved towards the anchor and this movement slackens the pull on the anchor and allowsthe flukes to dislodge from the sea-bed. It has been found that the pivotability of the flukes relative to the shank of the anchor greatly facilitates dislodgement of the anchor from the sea-bed whether the anchor is entrenched in soft material or lodged in underwater rocks.

The anchor can then be withdrawn from the water with the flukes lying open under the force of gravity. However, the flukes are not likely to damage the hull of the boat because on contact with the hull each fluke is freely collapsible. The compact nature of the anchor 10 when the flukes are collapsed facilitates storage and reduces the risk of the flukes causing any injuries on deck.

Furthermore, by reason of its simple construction, the anchor 10 is easily cleanable.

In a small anchor of the type described above, internal weights may not be necessary and instead a spacer tube of mild steel may be used as a washer between the bolt 23and the stock 27.

If no internal weights are required, the stock may be made longer so as to extend nearly up to the pivot points of the flukes and a shorter bolt is used for retaining the stock.

However, an anchor according to the present invention may be made in any desired size in which case the number and weight of the removable weights may be selected as desired.

It should be understood that any suitable pivoting mechanism may be employed to attach the flukes to the core so that each fluke is individually freely pivotable.

Claims (14)

1. An anchor comprising an elongate shank, and a plurality of elongate, generally flat flukes, each fluke having an end pivotally attached to the shank wherein the flukes are individually freely movable about their respective pivot point to pivot from a position in which they lie generally parallel to the shank to a position in which they extend obliquely outwardly from the shank.

2. An anchor according to claim 1 wherein the flukes can pivot up to 40 away from the shank.

3. An anchor according to claim 1 wherein the maximum pivot angle of each fluke is approximately 30 .

4. An anchor according to any preceding claim wherein the flukes are each provided with a plate extending generally perpendicularly to the main body of the fluke, and aligned with the length of the fluke, which plate is pivotally mounted in a longitudinal slot provided in the shank.

5. An anchor according to claim 4 wherein the plate is longitudinally slidably movable relative to the slot whereby the pivot point of the fluke is altered.

6. An anchor according to claim 4 or claim 5 wherein the plate on each fluke is locatable through the slot and it has an aperture fitted with a pin pivotally to retain the fluke on the shank.

7. An anchor according to any preceding claim in which the shank is of square section and comprising four flukes attached to an end of the shank, each being of-approximately the same width as the sides of the shank.

8. An anchor according to any preceding claim wherein the shank is hollow for accom modating one or more weights.

9. An anchor according to claim 8 wherein means are provided to enable insertion and removal of weights from the shank.

10. An anchor according to any preceding claim comprising a stock attachable to an end of the shank remote from the pivot points of the flukes.

11. An anchor according to any of claims 8 to 10 wherein the weights are slidably mounted on a bolt adapted to pass centrally along the length of the shank and which is securable to the stock.

1 2. An anchor according to claim 11 in which the bolt has a screw-threaded end adapted to cooperate with a complimentary screw-thread provided in a bore in an end of the stock.

1 3. An anchor according to claim 11 or claim 1 2 wherein rotation of the stock in the shank is restricted by a plastics bush which is removably attachable to the stock.

14. An anchor substantially as herein described and with reference to the accompanying drawings.