GB2336142A

GB2336142A - Anchor

Info

Publication number: GB2336142A
Application number: GB9807130A
Authority: GB
Inventors: David Charles Fisher
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-04-03
Filing date: 1998-04-03
Publication date: 1999-10-13
Also published as: GB9807130D0

Abstract

An anchor comprises a shank 2 having an anchor-line attachment point 4 at its distal end, a pair of flukes 7 pivotally connected to the proximal end of the shank about an axis transverse to the shank, a limit device 13,14,15 for limiting the angular movement of the flukes 7 with respect to the shank 2, and means for releasing the limit device on application of a tension in excess of a predetermined load on the attachment point 4. In use high tension on the anchor line will compress a main spring 20 causing a collar 62 to move away from a ring 17 welded to the shank 2, and the tongue 15 of a dog 14 to move out of a notch 13. This allows the flukes 7 to rotate freely.

Description

2336142 ANCHOR The present invention relates to an anchor.

A problem in the use of an anchor is that from time to time it can become fouled and difficult if not impossible to raise. Fouling can be in rocks, wrecks, chains etc. An anchor can hook onto such obstruction to the extent that it is impossible to pull it free.

The object of the present invention is to provide an improved anchor directed to solving this problem.

According to the invention there is provided an anchor comprising: 0 a shank having an anchor-line attachment point at its distal end; 0 a pair of flukes pivotally connected to the proximal end of the shank about an axis transverse to the shank; 0 0 a limit device for limiting the angular movement of the flukes with respect to the shank; and means for releasing the limit device on application of a tension in excess of a predetermined load on the attachment point.

In use, the anchor operates conventionally. Should it become fouled, the tension on its anchor line is increased above the normal load necessary to raise the anchor. When this reaches the predetermined load, the limit device is released and the flukes swing away from the shank, whereby they can pull away from the obstruction.

Normally the release means will be a spring loaded device adapted to locate a release member in a predetermined position with respect to the transverse axis until the predetermined load is applied and the release member is moved away from the axis. The release member can be a dog of the limit device acted on by a heavy spring. The limit device can also include a notched member connected to the flukes, whereby when the dog is withdrawn from the notched member, the latter is no longer angularly limited and flukes are free to rotate.

2 In the preferred embodiment, the dog is acted on by a light spring and the release member is a distal end fitting at the anchor line attachment point with a heavy spring arranged to transfer anchor line tension to the shank and a rod arranged to withdraw the dog. Further, the rod is slidable with respect to the end fitting, whereby the rod and the dog can be withdrawn from the notch without the predetermined tension being applied. It is to maintain the dog in the notch in the absence of the predetermined tension that the second lighter spring is provided.

To help understanding of the invention, a specific embodiment thereof will now be described by way of example and with reference to the accompanying drawings, in which:

Figure 1 is a plan view of the anchor in its normal configuration; Figure 2 is a similar view of the anchor as tripped; Figure 3 is a detailed cross-sectional view on the line Ill-III in Figure 1 of the anchor's end fitting; Figure 4 is a similar view on the line WAV in Figure 1 of the fluke angle limiting device in the normal configuration., and Figure 5 is a similar view on the line V-V in Figure 2 of the fluke angle20 limiting device in the tripped configuration.

Referring to the drawings, the anchor 1 thereshown has a hollow shank 2 having at its distal end 3 an anchor-line attachment point 4 in the form of an eye 5 in a movable fitting 6 held onto the shank in a manner described in more detail below. On opposite sides of the shank, the anchor has a pair of flukes 7, which are interconnected by a shaft 8, itself pivotally connected to the proximal end 9 of the shank by two bolted-on beari ng shel 1 s 10. The shaft has an axl s 11. B etween the bearing shells 10, the shaft has a boss 12 with a notch 13, with a defined angular extent. The shank is fabricated in bifurcated form at its end 9 and slidingly carries a dog 14 with a tongue 15. This latter extends into the notch and limits the angular movement of the flukes to say 30' about the axis 11 either side of the shank, the angular extent of notch being greater than 60' to allow for the thickness of the tongue 3 15. A spring 16 housed in the dog 14 and acting between it and the shank urges the dog towards the shaft so that it is normally engaged in the notch.

The movable fitting 6 at the distal end of the shank is comprised of two screwed together and bored out collars 61,62. The collar 61 has the eye 5 and the collar 62 has a bore 63 for the end of the shank. The latter includes an enlarged diameter, welded on ring 17 against which the collar 62 abuts. Within the fitting, the very end 18 of the shank is threaded and carries a nut 19. A main spring 20 is captivated on the shank between the nut 19 and the bottom of the internal bore 21 of the collar 62, and urges the latter against the ring 17. The final component is a rod 22 having a head 23 and a threaded end 24. The collar 61 has a counter bore 25 through which the rod passes with its head abutting the collar. The rod then extends through the shank to engage In a threaded bore in the dog 14.

In use the dog normally restricts the flukes to their 30' angular movement and the anchor acts conventionally. Should its flukes become snagged, unusual tension on the anchor line (not shown but shackled in use to the eye 5) will compress the main spring, with the collar 62 moving offthe ring 17. According to the release tension set in accordance with the threaded position of the nut 19 on the shank and of the threaded end 24 of the rod in the dog 14, and hence the state of compression of the springs necessary to lift the tongue 15 out of the notch 13, the flukes will be freed to rotate about the axis 11 when the tension in the anchor line reaches the state of compression just mentioned. (This load will of course be much higher than that the anchor would normally be expected to resist to hold its vessel in position.) When the flukes have swung free, the tongue bears on the boss 12 outside the notch, but with only the force of the lighter 16 of the springs. Thus when the anchor is retrieved, it is straight forward to swing the flukes back in line with the shank. The tongue reengages in the notch.

Typically the main spring requires 80 kg to compress it to its release position, whilst the light spring requires 10kg.

4 The invention is not intended to be restricted to the details of the above described embodiment. For instance, the anchor shown in the drawings is fabricated and can be manufactured of forgings. The dog may thus be enclosed by a portion of the shank forging.

Claims

CLAIMS:

1. An anchor comprising:

a shank having an anchor-line attachment point at its distal end; a pair of flukes pivotally connected to the proximal end of the shank about an axis transverse to the shank; 0 a limit device for limiting the angular movement of the flukes with respect to the shank; and 0 means for releasing the limit device on application of a tension in excess of a predetermined load on the attachment point.

An anchor as claimed in claim 1, wherein the release means is a spring loaded device adapted to locate a release member in a predetermined position with respect to the transverse axis until the predetermined load is applied and the release member is moved away from the axis.

An anchor as claimed in claim 2, wherein the release member is a dog of the limit device acted on by a heavy spring. 4. An anchor as claimed in claim 3, wherein the limit device includes a notched member connected to the flukes such that when the dog is withdrawn from the notched member, the latter is no longer angularly limited and the flukes are free to rotate.

5. An anchor as claimed in claim 4, wherein the dog is acted on by a light spring and the release member is a distal end fitting at the anchor line attachment point with a heavy spring arranged to transfer anchor line tension to the shank and a rod arranged to withdraw the dog. 6. An anchor as claimed in claim 5, wherein the rod is slidable with respect to the end fitting such that the rod and the. dog can be withdrawn from the notch without the predetermined tension being applied7. An anchor substantially as hereinbefore described with reference to Figures 1 to 4 of the accompanying drawings.

lo 2.