Patent ID: 6634076
Filing Date: 2003-10-21
Classification: F16L,Y10T

Abstract:
A method for joining at least one primary part and at least one secondary part; at least the primary part being partially or completely tubular defining a tube axis and having an at least partially curved circumferential wall at least partially encircling the axis; the secondary part having at least a body or wall part; said walls of the primary part and the secondary part comprising a joint edge, defining a) a joint line along said edge on said primary part wall, b) a joint plane drawn to contain said joint line, c) a joining direction having at least a direction component perpendicular to said joint line and said joint plane, d) a locking plane at least partially at the surface or within a section through said wall in which both the joint line and the joining direction lies and e) a normal direction being perpendicular to said locking plane; the primary part and the secondary part having locking structures, and whereinthe primary part comprises at least one positive or negative hook structure and the secondary part comprises at least one complementary positive or negative hook structure, wherein at least one stop surface that is integral to or separate from said primary or secondary part is arranged to restrict relative movement between the positive and negative hook structures in the normal direction, on each respective primary and secondary parts the hook structure is arranged in the locking plane, extending in the joining direction away from the joint line and having an undercut in the locking plane, on each respective primary and secondary parts the hook structure is open from at least one side of the locking plane when viewed along the normal direction, the joined locking structures on the primary and secondary parts having at least partially coinciding respective locking planes, the joint plane being substantially perpendicular to the axis or intermediate between perpendicular and axial, and at least one of the hook structures is arranged to provide locking in the axial, circumferential and radial directions, the method comprising the steps of moving the primary part and the secondary part mutually to a relative position in which the primary part locking plane is substantially parallel or coincides with the secondary part locking plane and in which the respective hook structures at least partially overlap when seen in the normal direction and with their open sides facing each other, and displacing at least the hook structures of the primary part and the secondary part in the normal direction to engage the positive and negative hook structures with at least partially fused respective locking planes.