EP 0447251 A2 19910918 - Tube and method of forming same.
Title (en)
Tube and method of forming same.
Title (de)
Rohr und Verfahren zur Herstellung.
Title (fr)
Tube et son procédé de fabrication.
Publication
Application
Priority
GB 9005703 A 19900314
Abstract (en)
A polygonal tube is produced from metal strip by forming rows of recesses (15) and projections (16) along opposite edges of the strip and then bending the strip until each projection is received in a corresponding recess to form the tube. The projections are then squeezed between opposed surfaces (26,28) one inside and other outside the tube. The surface inside the tube forms a groove (27) in the tube wall at the inside of the tube, spreads each projection to take up any clearance between edges of the projections and boundaries of the corresponding recesses. The surface outside the tube allows the tube to remain flat. <IMAGE>
IPC 1-7
IPC 8 full level
B21C 37/15 (2006.01); B21D 39/03 (2006.01)
CPC (source: EP)
B21C 37/155 (2013.01); B21C 37/157 (2013.01); B21D 39/037 (2013.01)
Designated contracting state (EPC)
AT BE CH DE DK ES FR GB GR IT LI LU NL SE
DOCDB simple family (publication)
EP 0447251 A2 19910918; EP 0447251 A3 19911204; EP 0447251 B1 19940518; AT E105748 T1 19940615; DE 69102000 D1 19940623; DE 69102000 T2 19940901; ES 2052332 T3 19940701; GB 2244015 A 19911120; GB 2244015 B 19931027; GB 9005703 D0 19900509; WO 9305903 A1 19930401
DOCDB simple family (application)
EP 91302205 A 19910314; AT 91302205 T 19910314; DE 69102000 T 19910314; ES 91302205 T 19910314; GB 9005703 A 19900314; GB 9101588 W 19910917