Patent Application
20050098005
The present invention relates to the cutting off or truncation of elongate metal structural members.
In various industries, it is necessary to truncate structural members, either trimming them to a desired length, or removing unwanted material. In the off-shore petroleum industry, for example, for the decommissioning of drilling and production platforms, it is of importance to remove the support legs or pilings as close to the sea bed as possible. Conventionally, this involves the use of divers working with thermal cutting tools, explosives or both. The conventional procedures are time consuming and costly.
The truncation of concrete piles is known using cutters as described in commonly owned U.S. Pat. Nos. 5,319,006 and 5,413,086, the entire disclosures of which are incorporated herein by reference. European patent application 243,981 discloses a cutter for concrete piles which may include steel cylinders grouted with the concrete and used as off-shore platform piles. The known concrete cutters are not, however suitable for cutting metal structural members, including ungrouted tubular members, wide flange beams and other shapes. It has been found that the blades used for concrete will not stand up to the stresses encountered in cutting off metal members. In addition, the force pressing the blade into the member may cause the structural member to deform and collapse rather than cutting completely through. Where the parts are not completely severed, there is a “snag”, the remaining connection between the parts, preventing their free separation. This is particularly noticeable with hollow tubular members.
The present invention aims at the provision of a cutter that is capable of truncating elongate structural members of various configurations and materials, including metal hollow members, whether grouted or not.
According to one aspect of the present invention there is provided a method for cutting off an elongate structural member transversely of the member, said method comprising:
Preferably the member is supported at support positions spaced from respective opposite sides of the median plane of the blade, leaving a pocket between the support positions into which the blade may penetrate to ensure a complete severing of the member.
According to another aspect of the present invention there is provided a cutting tool for cutting off an elongate metal structural member transversely of the member, said tool comprising:
Preferably the support has two spaced apart components for supporting the structural member at support positions on respective opposite sides of the blade.
The symmetrical blade has been found to resist the stresses encountered in cutting metal structural members. The cutting edge is preferably defined by the intersection of two surfaces meeting at an included angle not less than 45°. This is preferably backed by a secondary bevel of smaller angle, for example 17°. The combination yields an overall bevel that is only slightly greater in depth than the thickness of the blade, for example a 3 inch depth for a blade thickness of 2.5 inches. Existing concrete cutters have a bevel depth of approximately 10 inches for a 2.5 inch blade thickness. In use, the cutter tips upwardly at the rear and when cutting metal, the long bevel has a tendency to bend, severely restricting the life of the blade.
Where the structural member is an ungrouted, hollow, tubular member, the cutting edge may be used as a primary cutting edge supplemented by two secondary beveled cutting edges transverse to the primary cutting edge, and for engaging the tubular member therebetween to score lateral bulges that may be formed by flattening of the member as it is pressed between the primary cutting edge and the support. The secondary cutting edges are preferably formed on the blade.
In the accompanying drawings, which illustrate exemplary embodiments of the present invention:
Referring to the accompanying drawings, there is illustrated a cutting tool 10 for cutting off an elongate structural member, in this embodiment a hollow cylindrical metal member 12.
The tool includes a frame 14 including a rear cross member 16, two side rails 18 and an end gate 20. The frame is constructed generally as described in U.S. Pat. No. 5,139,006, the disclosure of which has been incorporated herein, as noted above. In this frame, however, the end gate 20 has a lateral pocket 22 extending the width of the frame, between respective components 24a and 24b of a support 24.
The side rails 18 have inwardly facing channels 26 (
The blade 28 is a flat steel plate 34 with a double bevel 36 along the cutting edge 38. The bevel 36 is symmetrical about a median plane 40. The cutting edge 38 is defined by the intersection of two surfaces 42a and 42b meeting at an included angle of approximately 50°, and not less than 45°. The secondary, backing bevel 44 is defined by two surfaces 44a and 44b having an included angle of approximately 34°. The result is a combined bevel depth of 3 inches for a plate thickness of 2.5 inches.
In use of this tool, the structural member 12 is positioned between the blade 28 and the support 24 on the end gate 20. The cylinders 32 are actuated to drive the cutting edge 38 into and through the member 12, into the pocket 22 between the support components 24a and 24b. this provides a complete severing of the member with no snags.
An alternative embodiment of the blade 46 is illustrated in
While particular embodiments of the present invention have been described in the foregoing, it is to be understood that other embodiments are possible within the scope of the invention. It is also to be understood that the invention is not limited to use in cutting hollow cylindrical members, but is useful for cutting off structural members of most any form, including tubes of any cross section: circular, square or other polygonal, whether hollow or grouted, and other shapes, for example I beam, Wide Flange or H beam configurations. The invention is therefore to be considered limited solely by the scope of the appended claims.
