The present invention relates to mechanical engineering, and, more particularly, to machines for edge forming of sheets for welding.
The present invention can most advantageously be used in making welded pipes of a diameter ranging from 800 to 2500 mm from sheets.
Known in the art is a machine for machining lateral edges of sheets longitudinally moving in a production flow in a horizontal plane.
This machine comprises driven rolls for feeding a sheet being machined to oppositely mounted fixed cutting tools arranged along the edges being machined. Support rollers are mounted adjacent to the cutting tools above and beneath the sheet being machined.
The support rollers are mounted on supports each being arranged on either sheet edge being machined. The axles of the upper rollers are rigidly fixed, and the axles of the lower rollers are adjustable depending on the sheet thickness. In addition, each support has a movable carriage with a cutting tool which is loaded by a compression spring, the spring cooperating with the support through a screw.
The supports are adjustably mounted according to the sheet width on a transverse beam extending over the sheet. The transverse beam is pivotably connected to a support means by two parallel drawbars extending over the sheet in the direction opposite to the direction of the sheet movement. To limit the displacement of the cutting tools towards each other, the carriages are provided with positioning rollers cooperating with the sheet edges being machined.
The above-described machine cannot ensure a high-speed machining in a single pass with optimal sheet edge cutting conditions with a considerable thickness of sheets from 10 to 30 mm and with an allowance of up to 20 mm for machining per each edge of the sheet since the machining of each edge is effected with a single cutting tool so that several passes are required to machine each edge with an allowance of 20 mm with the sheet thickness from 10 to 30 mm, whereby the efficiency of the machine is low.
In addition, it is very important that the above described machine does not possess sufficient stiffness of the system of "machine-tool-workpiece" since the transverse beam mounting the supports is pivotably connected to the support means. Therefore, as the sheet moves, each cutting tool follows unevenness of the surface and fails to straighten out crescent-shaped edges which frequently occur in practice.
The latter circumstance restricts the field of application of the known machine. Thus, this machine cannot be used for edge forming of sheets in the manufacture of large-diameter pipes (from 800 to 2500 mm) since very stringent requirements are imposed on such sheets as regards both the parallel relationship between the opposite edges and the rectilinearity thereof.