WO2008133529A1

WO2008133529A1 - Link element for a cutting chain, and a chain with cutting link elements

Info

Publication number: WO2008133529A1
Application number: PCT/NO2008/000153
Authority: WO
Inventors: Harald Ramfjord
Original assignee: Beerenberg Frontier As
Priority date: 2007-04-30
Filing date: 2008-04-29
Publication date: 2008-11-06
Also published as: NO20072216L; NO327555B1

Abstract

The present invention concerns a link element for a cutting chain (4) that is adapted to extend freely between two points (21, 22) and for pivotal attachment to the chain (4). The link element includes at least one portion (1) with a cutting or abrasive surface (6). Furthermore, the invention concerns a chain (4) adapted to extend freely between two points with at least two, in each other attached link elements of the above mentioned type.

Description

Link element for a cutting chain, and a chain with cutting link elements

The present invention concerns a link for a cutting chain, and a chain with such links. During cutting of some structures, it is common to use cutting wires with elements where abrasive and cutting particles are attached, typically synthetic diamonds. The diamonds are normally attached to steel rings that are threaded on to a wire and that are attached to the wire. Between the steel rings or the cutting elements it is usually placed spacers, and these are also attached to the wire. Structures in this connection may be large vessels or offshore installations that are to be split into parts for the decommissioning or removal.

However it is a problem with such wires that the wire is stretchable. This is particularly a great problem at long wire lengths. When the wire can be stretched, the cutting elements or rings that are attached to the wire has a tendency to work loose from the wire, such that they slide along the wire and create areas on the wire without cutting elements and such that the wire is exposed. In these places, the wire is in many cases worn quickly, and this leads to wire breakage. Furthermore this may create inaccuracies during cutting, and may lead to jamming of the wire or uneven operation. Typical for cutting wires of this kind is that the wire runs freely between two points, and the wire thereby runs freely through the object that is to be cut.

Cutting chains with fixed link elements are well known within subject areas with "chain-saw technology". The chain-saw chains can however not be compared with freely running saw-wires as these chains runs on a blade, and elements on the chain usually extend into slot on the blade for guiding the chain. Extension of such chains is normally not a problem as long as the chain is maintained sufficiently tight.

Thereby it is a purpose with the present invention to provide a cutting chain, and an element for a cutting chain as defined in the present patent claims. The present invention concerns a link element for a cutting chain that is adapted to extend freely between at least two points. The link element is adapted for pivotal attachment in a chain wherein the link element includes at least one portion with a cutting or abrasive surface. With freely extending in this connection it is meant that the chain is tensioned between two points, and that the chain between these points not is carried, supported or guided in any way, such that the force the chain presses against the object that is to be cut with, only is taken up by the chain. The chain is in other words not supported by a blade common in connection with chain saws frequently used in connection with cutting wood, and do therefore not include elements for cooperation with a slot for guidance of the type that is common for chainsaws with a chain and a cutting blade.

The cutting or abrasive surface may be formed by cutting or abrasive particles attached to the link. An example of abrasive particles is synthetic diamonds, sintered grains of hard metal, ceramic materials etc. The particles may be sintered, adhesively bonded, or attached in any other way, well known within the subject area.

The link elements include a first and a second end, and each end may be adapted for pivotal attachment to a different corresponding cutting link. Thereby all the link elements may be similar, such that these easily can be exchanged, and such that a manufacturing process easily can be standardised.

The pivotal attachment may allow pivoting in one or two directions of motion. In this connection it may be used joints of any suitable type, and it is shown a joint with a cottet pin or peg pressed into holes in the link, such that peg or cottet pin not moves out of the link. The hole in one of the links may have a press fit to the peg and the hole in the other link may be adapted such that it is allowed pivoting in relation to the peg. Alternatively, may a portion of the peg include a threaded part that engages into threads in one of the links or may be attached in any other way. Links with a ball in a ball socket could for instance also be used. Links with a peg and hole may also be made with sufficient clearances such that the links are allowed a considerable rotation about a first axis and a small rotation about a second axis.

Alternatively the links may be attached to each other with open gimbal joints.

The links may have a central axis in the longitudinal direction of the link elements. The pivotal attachments may be made such that each link element can be attached in another corresponding link element in such a way that the longitudinal central axis of the links may be coinciding. In this way the cutting elements will follow the same path. The link elements may include at least one area with a substantially circular cross section and the portion with a cutting or abrasive surface may be attached in a circumference around the link elements at the substantially cross section. This is particularly important if the link elements are to be attached to a chain that can be rotated about its own axis. If the link elements not are to rotate about their own axis, and the chain only shall cut in a pre determinant direction, the cutting surface do not need to extend all the way around the link. The area with a substantially circular cross section, with at least one portion with a cutting or abrasive surface, may be shaped as an elevation with a dually curved surface. The dually curved surface may typically have a ball or barrel shape.

The invention also concerns a chain adapted to extend freely between at least two points with at least two, mutually connected link elements as described above. In some connections may intermediate elements be placed between the link elements if it, for instance at great chain lengths, turns out that the tension in the chain becomes excessive with to many cutting elements, or that intermediate elements for some reason or with other functions are desired. Of course the chain may also include link elements where all the link elements in the cutting portion of the chain include a cutting or abrasive surface. The links may allow pivoting of the link elements about one axis. The links may allow pivoting of the link elements about two axes. On a chain as described above the link elements may include at least one area with a substantially circular cross section and the particles may be applied or attached in a circumference about link elements at the substantially circular cross section. The links may be made of steel or any other suitable material.

Short description of the enclosed figures: Figure 1 shows a chain assembled of several links according to the invention;

Figure 2 shows how links according to the invention may be linked to each other in a first embodiment; Figure 3 shows a saw with a chain according to the invention;

Figure 4 shows a chain with a link where two cutting elements are placed on the same link;

Figure 5 shows a second embodiment of two links according to the invention, where the links are free to move in two degrees of freedom;

Figure 6 shows yet a further embodiment of two links according to the invention; and

Figure 7 shows an example of a chain with a link according to the invention, in a perspective view.

Detailed description of embodiments of the invention

On figure 1 it is shown a side elevation of embodiments of the invention. On figure 1 it is shown a side elevation of a chain 4 with five link elements according to the invention. The link elements are linked to each other in joint 3 where a trough going peg or cottet pin 5 is placed in hole 10 such that the link elements are allowed to pivot or rotate in relation to each other. Each link element has a cutting portion 1 that may include a ball shaped portion. The link element is preferably cast/moulded or machined in one piece, and the ball shaped cutting portion or element 1 is applied with synthetic diamonds or other suitable cutting elements. For cutting in soft materials, may alternatively the cutting element 1 be applied with a suitable cutting structure formed directly in the material.

Each link element may include a first end 8 and a second end 9 at each side of the cutting element 1. In the shown embodiment is the first and the second end shaped as cylindrical portions with a smooth or a slick portion 7. The first end 8 and the second end 9 may however be formed with any suitable cross section. If the chain is designed to revolve about its own axis, is however a cylindrical cross section well suited.

In the shown embodiment may the link elements pivot in one degree of freedom in relation to each other, but also in this embodiment, the joint 3 may be made with tolerances to allow a certain motion of the link elements in two degrees of freedom.

The cottet pins 5 holding the links together may be made with a press fit, and the cottet pins 5 may be manufactured such that they are easily pressed out and assembled to exchange one link elements, or for easily to be able to provide chains of various length. The cutting elements 1 with a cutting surface 6 of synthetic diamonds 2 may also have other shapes than a ball shape, for instance may the cutting elements 2 be substantially cylindrical, include an oval shape, etc. However a ball shape has proved favourable to prevent jamming of the chain. Figure 2 shows a link element according to the invention with a cutting portion 1 , a hole for a cottet pin 10, a first end 8 and a second end 9 with a hole 10 for a peg and with a cutting surface 6.

At the lowermost part of Figure 2 it is shown an example of a link element with a cottet pin 5. In the embodiment shown on figure 2 it is clearly shown an embodiment where a first end 8 and a second end 9 of the link element may be similar. Furthermore it is in Figure 2 shown that the joints 3 of the link elements may be placed at 90° in relation to each other, such that a chain is allowed several degrees of freedom even if each joint 3 only is allowed one degree of freedom. This solution may however in some cases give unfavourable stresses in the chain. The smooth part 7 may be cylindrical, or have other shapes.

In figure 3 it is shown a saw with a chain 4 according to the invention where a saw bow 20 holds a distance between the attachment points 21 , 22 for the chain 4. A propulsion/drive unit 23 may drive the chain with an oscillating motion back and forth such that the chain moves in relation to a work piece (not shown) that is to be cut. A synchronised propulsion unit 24 may ensure that chain 4 remains tight. Alternatively the propulsion unit 4 may be a passive unit that only imposes a biasing force for the chain to maintain a tension, at the same time as an oscillating motion is allowed. The chain 4 may be driven in rotation, such that the chain 4 rotates about its own axis during operation. A propulsion unit to drive the rotating motion (not shown) may be placed at one end, or in both ends, to reduce the twisting load torque on the chain. On Figure 3 it is shown a saw bow 20 to illustrate that the attachment points of the chain 21 , 22 must be kept at a distance from each other. However the saw bow may of course be substituted with any sort of other attachments for the attachment points 21 , 22 as long as the desired tension on the chain can be imposed.

Alternatively the chain may run in loop, common for diamond saws with diamond saw wire, band saws and the like. If the chain is to allow rotation about its own axis also in this embodiment, must the links be allowed to move in two degrees of freedom in relation to each other.

In the cases where the requirement for the chain to be allowed to bend is limited as with the solution with an oscillating back and forth motion, is the requirement for the chain to move small, and two or several cutting elements may be placed at each link.

Figure 4 thereby shows an example of a chain 4 where each link includes two cutting portions 1 with cutting elements. However it may in some applications be preferable with even more than two cutting portions 1 with cutting elements on each link element. Each cutting element does not necessarily have the same shape. The figure also shows cottet pins 5 for connection with the links of the link elements.

Figure 5 shows two link elements with cutting portions 1 according to the invention, where these are attached to each other such that it is allowed pivoting in two degrees of freedom. The shown solution includes a universal joint or "open gimbal joint" with a cross 11. However this is only shown as an example of a joint 3 that allows pivoting about two degrees of freedom, and any kind of joint 3 for this purpose, well known within many subject areas, may be used.

Figure 6 shows yet another embodiment of a link element with a cutting portion 1 , where a cottet pin 5 extends though borings in the links. In the shown embodiment the link has clearances or tolerances such that it is allowed a certain motion of the link in two degrees of freedom.

The cross sectional area of the parts of the link, may be substantially uniform, such that the tensions the link is exposed to for the two hinged together elements are substantially the same.

Figure 7 is a perspective view of a chain of links according to the invention showing the ball shaped cutting elements and the cylindrical smooth portions.

In the shown embodiments, each link element is shaped as one piece applied with a cutting surface. However each link element may of course be assembled of several elements that are screwed or in any other way connected to each other. It is an essential feature with the invention that any extension or flexibility of the chain not will result in any substantial aggregation of cutting elements, which would give areas without cutting elements, with those unfavourable consequences this would give.

Claims

P a t e n t c l a i m s

1. A link element for a cutting chain (4) that is adapted to extent freely between at least two points (21 , 22) and for pivotal attachment to the chain (4), said link element including at least one portion (1) with a cutting or abrasive surface (6), c h a r a c t e r i z e d i n that: the portion (1 ) with a cutting or abrasive surface (6) is placed at an area of the link element with a substantially circular cross section.

2. The link element according to claim 1 , wherein the cutting or abrasive surface (6) is formed by cutting or abrasive particles (2) applied to the link element.

3. The link element according to claim 1 , wherein the cutting or abrasive particles (2) are synthetic diamonds.

4. The link element according to claim 1 , wherein the link element include joints (3) at a first and second end (8, 9), at each end (8, 9) and is adapted for pivotal attachment in a second corresponding cutting link element in these joints (3).

5. The link element according to claim 3, wherein the pivotal attachment allows pivoting in two directions of motion.

6. The link element according to claim 3 with a central axis in the longitudinal direction of the link element, wherein the pivotal attachment is designed such that the link elements may be attached to second corresponding link element and such that the longitudinal central axis of the link elements are coincid- ing.

7. The link element according to claim 1 , wherein the area with a substantially circular cross section with at least one portion (1) with cutting or abrasive surface (6) is shaped as an elevation with a dually curved surface.

8. A chain (4) adapted to extend freely between at least two points (21 , 22), c h a r a c t e r i z e d i n at least two in each other attached link elements according to claim 1.

9. The chain (4) according to claim 8, wherein intermediate elements are placed between the link elements.

10. The chain (4) according to claim 8, wherein all the link elements in the cuttings portion (1) of the chain (4) includes at least one cutting or abrasive surface (6) and the link elements are linked to each other.

11. The chain (4) according to claims 9-10, wherein the joints (3) allow pivoting of the link elements about one axis.

12. The chain (4) according to claims 9-10, wherein the joints (3) allow pivot- ing of the link elements about two axes.

13. The chain (4) according to claims 8-12, wherein the link elements includes at least one area with a substantially circular cross section and where cutting or abrasive particles (2) are applied at a circumference around the link element at the substantially circular cross section.