WO2013175060A1

WO2013175060A1 - Securing link for anchor chain, cable or rope

Info

Publication number: WO2013175060A1
Application number: PCT/FI2013/050516
Authority: WO
Inventors: Heikki Paakkinen
Original assignee: Wello Oy
Current assignee: Wello Oy
Priority date: 2012-05-23
Filing date: 2013-05-13
Publication date: 2013-11-28
Anticipated expiration: 2014-11-23
Also published as: EP2852523B1; FI123754B; EP2852523A1; EP2852523A4; PT2852523T; FI20125546A7

Description

Securing link for anchor chain, cable or rope

The present invention relates to a securing link for an anchor chain, cable or rope, the securing link comprising a plurality of elongated turning elements, the first of which turning elements is connected to the load to be anchored and the last of which turning elements is connected to the anchor chain, ca^¬ ble or rope, and which turning elements are provided with pivots or similar shafts, by means of which the turning elements are connected at their ends as extensions of one another, and which turning elements are arranged to turn with respect to one another on pivots or the like.

Anchor chains, cables or ropes are used for many purposes. One such purpose is to position a (floating) object on the surface of a water body, or below the water surface of a water body, to a desired location. Conventionally, boats and ships are positioned by means of an anchor fixed to the end of an anchor chain, cable or rope, the said anchor being lowered to the bottom of the water body from a boat or a ship which has a securing link for an anchor chain, cable or rope. In large ships this may be a big reel, in smaller boats it may be a securing ring fixed to the hull, to which the other end of, for ex- ample, the anchor rope is attached.

Recently have also been developed power plants based on the wave motions of water, which are positioned by anchoring them from their body on the surface of the water. A securing link is connected to the body for this pur- pose. Especially the corrosive effect of sea water and the mechanical stress caused by the reciprocating movement of a floating body on the equipment used for anchoring especially power plants, but also boats and ships, present a challenge to the anchoring equipment. The construction of especially the securing link of an anchor chain, cable or rope is such that the movement caused in it by the anchor chain, cable or rope causes the material of the parts of the securing link to rub strongly against each other, particularly in the area of the supporting points between the parts. In long-term anchoring (wave power plants), especially in corrosive conditions (sea water), this is extremely detrimental and wears the material. Consequently, there is a considerable risk of the securing link wearing down at the point of rubbing (sup- porting point between two parts of the securing link) and breaking, whereby the positioned object will detach from its anchoring.

The aim of the present invention is to provide a securing link by means of which the above-mentioned disadvantages can be eliminated or at least sub- stantially reduced.

To achieve the above aim, the present invention is characterised in that at least one turning element is provided with an elongated opening, into which the pivot or similar shaft of an adjacent turning element is fitted, the said pivot or similar shaft forming a rolling shaft, which is fitted along the edge of the said elongated opening, the said at least one turning element turning with respect to the said adjacent turning element.

By means of the securing link according to the invention is avoided the prior art rubbing together of the material of the parts of the securing link. This in turn lengthens the service life of the securing link in comparison to the prior art securing links.

Preferred embodiments of the invention are disclosed in the dependent claims.

The invention is described in greater detail in the following, with reference to the accompanying drawings, in which: Figure 1 shows a front view of a preferred embodiment of the securing link according to the invention, Figure 2 shows a side view of the securing link of Figure 1, and

Figure 3 shows an axonometric view of the securing link of Figures 1 and

2.

Figures 1 and 2 thus show a preferred embodiment of the securing link for an anchor chain, cable or rope according to the invention. The securing link is denoted by reference numeral 1, the diagrammatic body of the wave pow- er plant by reference numeral 2. The body 2 and the wave power plant itself is, therefore, an example of a load 2 to be anchored and it is arranged to float on the sea surface. The securing link is located below water level. In addition to this, the diagrammatically presented anchor chain is denoted by reference numeral 6.

Figures 1 and 2 show that the securing link 1 is comprised of a plurality of elongated turning elements connected as extensions of one another, the elements being denoted by reference numerals 3, 4 and 5. As material for the securing link 1 is preferably used steel or stainless or acid-proof steel alloys. The first turning element 3 is connected to the load 2 to be anchored. In this case, the first turning element 3 is fixed by its first end directly to the body 2 of the wave power plant. The first turning element 3 is preferably comprised of two lugs 3a and 3b arranged at a distance from one another. Between the other ends of the lugs, in other words, at the second end of the first turning element 3, is arranged a pivot 3c or similar shaft which is immovable with respect to the first turning element 3. The pivot 3c constitutes the rolling shaft 3c according to the invention. A second elongated turning element 4 is connected pivotably with respect to the first turning element 3 through the rolling shaft 3c. The second turning element 4 is comprised of two parallel elongated walls 4a and 4b, which are arranged at a distance from one another and which are here connected to one another from a connecting part formed in connection with the first end, which forms the first end of the second turning element 4. Between the walls, at the second end of the turning element 4, thus remains a slot-like opening 4'. The second turning element 4 thus forms a slot-like piece (having the cross-sectional shape of a turned letter U), against the upper edge 4c' (contact surface) of the elongated opening 4c formed at the first end of which the rolling shaft 3c rests. The first end of the second turn- ing element 4 has a width which allows it to be fitted between the lugs 3a and 3b of the first turning element 3. This can be seen especially in Figure 2. Figure 2 also shows that the second turning element 4 is arranged to turn with respect to the first turning element 3 on the rolling shaft 3c of the first turning element 3.

At the second end of the second turning element 4, between the walls 4a and 4b, in the slot-like opening 4', is arranged a second pivot 4d or similar shaft, the direction of the longitudinal axis A2 of which is transverse to the direction of the longitudinal axis Al of the rolling shaft 3c. The joint pin 4d forms a second rolling shaft 4d. A third elongated turning element 5 is connected pivotably with respect to the second turning element 4 through the second rolling shaft 4d, the third turning element 5 being the last turning element 5 of the securing link 1 according to the example. Here, the last turning element 5 is a single elongated turning element, the first end of which is fitted between the walls 4a and 4b of the second turning element 4. The first end of the last turning element 5 is provided with an elongated opening 5a, which is fitted in conjunction with the second rolling shaft 4d in such a way that the second turning element 4 and the last turning element 5 turn with respect to one another on the second rolling shaft 4d. The second end of the last turning element 5 is provided with a second opening 5b. In conjunction with the second opening 5b is arranged an anchor chain, cable or rope 6. Figures 1 and 2 show an anchor chain 6 which is arranged in conjunction with the opening 5b so as to be pivotable by one link. In the opening 5b may be fitted, for example, a separate joint pin 6a of the anchor chain 6. The first end of the anchor chain 6, which forms the turning element 6b, may be connected to the joint pin 6a in such a way that the last turning element 5 and the anchor chain, cable or rope 6 will turn with respect to one another around a shaft parallel to the longitudinal axis of the joint pin 6a.

The Figures show that the upper edge 4c' of the opening 4c of the securing link 1 and the opening 5a are made longitudinal in accordance with the invention, for example, the shape of a stretched circle. An example of the functioning of such elongated openings may be presented by means of the opening 5a of the first end of the last turning element 5 and the second rolling shaft 4d fitted through it. It should be noted that there may be one to three of the elongated openings according to the invention in the securing link 1 according to the example (if necessary, the opening 5b may also be made into an elongated opening). Should there be more turning elements than the three shown, there may in that case be more elongated openings than the said three in the securing link.

Figure 2 shows the so-called initial position, in which the turning elements 3, 4 and 5 are successively in line with respect to one another. When tractive force is exerted on the anchor chain 6, the second rolling shaft 4d rests against the edge of the opening 5a shown in Figure 2, more specifically against the upper edge 5a' (contact surface). At the same time, the joint pin 6a rests against the lower edge of the opening 5b. In Figure 2, the tractive force is a force directed downwards or essentially downwards.

When the last turning element 5 turns right with respect to the second rolling shaft 4d, for example, to an angle a, typically 1-5 degrees, the joint pin 4d moves left (correspondingly also right) from its initial position in opening 5a. Here, the initial position is in the centre of the opening 5a. The turning elements 4 and 5 thus turn with respect to one another from the position in Figure 1 to angle a. The joint pin 4d moves by rolling in accordance with the invention. The rolling takes place in such a way that the cylindrical surface of the rolling shaft 4d rolls along the edge of the opening 5a, namely the upper edge 5a' (linear contact surface), when the tractive force is exerted on the anchor chain 6 and the turning element 5 turns. The contact surface between the upper edge 5a' and the cylindrical surface of the rolling shaft 4d moves as the cylindrical surface of the rolling shaft 4d rolls. The (imaginary) pivoted shaft between the turning elements 4 and 5 is thus this moving contact surface.

It is also noted, that a linear load is exerted between the cylindrical surface of the second rolling shaft 4d and the upper edge 5a' (contact surface). In this way is avoided, for example, the point load between the links of prior art chains. This type of linear load is distributed more widely than a point load. Thus, the surface pressure is lower in the securing link according to the invention. This fact combined with the rolling described above naturally lead to there being less stress and wear in the area of the securing link rolling shaft 4d and the upper edge 5a' of the opening 5a.

Furthermore, it is advantageous to make the opening, for example opening 5a, curved in the longitudinal direction. The upper and lower edges 5a' and 5a" of the opening 5a may be made radially curving. In general, it may be said that the radius of curvature of the opening is selected in such a way that it corresponds to at least the distance between the contact surface of the opening and the longitudinal axis of the nearest parallel rolling shaft. This distance typically equals 1.5 to 3 times the distance between two adjacent rolling shafts, but may deviate from this, if necessary. By means of the construction according to the invention are avoided the rubbing and sliding movements of the parts of the securing link against one another, which occur in the prior art. This is extremely advantageous, especially in the corrosive conditions caused by sea water, where lubrication be- tween the pieces cannot be used.

The present invention is not limited merely to the embodiments disclosed, but it may be applied in many ways within the scope of protection determined by the claims. In addition to the examples disclosed above, applica- tions may include the drilling rigs of the oil and gas industries, and loads 2 and objects anchored or fixed to the ground (on dry land), such as hot-air balloons. Depending on the application, the material used for the securing link may be, for example, wood, plastic, a fibreglass composite, a carbon fibre composite, a natural fibre composite, aluminium and/or an aluminium alloy.

Claims

1. A securing link (1) for an anchor chain, cable or rope (6), the securing link (1) comprising a plurality of elongated turning elements (3, 4, 5), the first of which turning elements (3) is connected to the load (2) to be anchored and the last of which turning elements (5) is connected to the anchor chain, cable or rope (6), and which turning elements (3, 4, 5) are provided with pivots (3c, 4d) or similar shafts, by means of which the turning elements (3, 4, 5) are connected at their ends as extensions of one another, and which turning elements (3, 4, 5) are arranged to turn with respect to one another on pivots (3c, 4d) or the like, characterised in that at least one turning element (5) is provided with an elongated opening (5a), into which the pivot (4d) or similar shaft of an adjacent turning element (4) is fitted, the said pivot (4d) or similar shaft forming a rolling shaft (4d), which is fitted to roll along the edge (5a of the elongated opening (5a), the said at least one turning element (5) turning with respect to the said adjacent turning element (4).

2. A securing link (1) as claimed in claim 1, characterised in that elongated openings (4c, 5a) are arranged in two or more turning elements (4, 5).

3. A securing link (1) as claimed in claim 1 or 2, characterised in that in one or more turning elements (5) are arranged two elongated openings (5a, 5b).

4. A securing link as claimed in any of the above claims 1 to 3, characterised in that the elongated opening (4c, 5a) is made curved in its longitudinal direction, whereby the rolling shaft (3c, 4d) corresponding to it rolls along the curved edge (4c', 5a of the opening (4c, 5a).

5. A securing link as claimed in any of the above claims 1 to 4, characterised in that the outer surface of the rolling shaft (3c, 4d) is cylindrical, and that on the point of contact between the cylindrical surface of the rolling shaft (3c, 4d) and the upper edge (4c', 5a of the opening (4c, 5a) is exerted a linear load.

6. A securing link as claimed in any of the above claims 1 to 5, characterised in that the material of the securing link (1) is steel or an acid-proof steel alloy.

7. A securing link as claimed in any of the above claims 1 to 6, character- ised in that the material of the securing link (1) is wood, plastic, a fibreglass composite, a carbon fibre composite, a natural fibre composite, aluminium and/or an aluminium alloy.