Apparatus and method for perforating tubing and method of producing part of such apparatus

A method of perforating tubing, the method comprising:

• advancing the tubing along an axial path thereof,
• simultaneously rotating at least one pair of outwardly directed cutters in opposite directions about respective fixed axes which are spaced from and substantially parallel to said axial path of the tubing, the cutters rotating along fixed circular paths which intersect the tubing at discrete points, and
• synchronizing the rotation of the cutters for substantially simultaneous intersection with the tubing whereby the cutters support the tubing to restrain it against rotation during operative intersection of the tubing by the cutters.

A method of perforating corrugated tubing, the method comprising the steps of advancing the tubing along an axial path thereof, and simultaneously rotating at least one outwardly directed cutter through complete revolutions about a fixed axis from which the cutter is spaced and which is spaced from and substantially parallel to said axial path of the tubing, said rotation of the cutter being along a fixed circular path which intersects the tubing thereby to perforate the tubing by intermittent intersection of the tubing by the cutter at discrete points on the tubing, the tubing being supported and being restrained against rotation thereof about said axial path during intersection of the tubing by the cutter, wherein said advancing of the tubing along said axial path thereof comprises rotatably driving at least one lead screw member which is disposed substantially parallel to said axial path of the tubing and screw threading of which is in meshing engagement with corrugations presented by the tubing, the cutter which is mounted on the lead screw member being rotated therewith.

A method of perforating corrugated tubing, the method comprising the steps of advancing the tubing along an axial path thereof, and simultaneously rotating at least one outwardly directed cutter through complete revolutions about a fixed axis from which the cutter is spaced and which is spaced from and substantially parallel to said axial path of the tubing, said rotation of the cutter being along a fixed circular path which intersects the tubing thereby to perforate the tubing by intermittent intersection of the tubing by the cutter at discrete points on the tubing, and the tubing being supported and being restrained against rotation thereof about said axial path during intersection of the tubing by the cutter, wherein said advancing of the tubing along said axial path thereof comprises rotatably driving at least one lead screw member which is disposed substantially parallel to said axial path of the tubing and has screw threading in meshing engagement with corrugations of the tubing, said method further comprising the step of stopping advance of at least the intersected part of the tubing along the axial path thereof during intersection of the tubing by the cutter.

Apparatus for perforating corrugated tubing, the apparatus comprising:

• drive means for advancing the tubing along an axial path thereof, said drive means comprising at least one lead screw member having screw threading for meshing engagement with the corrugations of the tubing, the lead screw member being rotatably drivable about a fixed axis spaced from and substantially parallel to said axial path of the tubing for advancing the tubing therealong,
• at least one outwardly directed cutter mounted on a respective said lead screw member for rotation therewith about said fixed axis along a fixed circular path which intersects the tubing for intermittent intersection of the tubing by the cutter at discrete points on the tubing, and
• support means for supporting the tubing and restraining the tubing against rotation thereof about said axial path during operative intersection of the tubing by the cutter.