Abstract: A rupturable can member (10) of sheet metal has a pair of scorings (16) which define a tearing strip (18) laterally. Welded onto the tearing strip (18) is a tongue (20), which has a thickened portion (24) at its welded-on end (22). This thickened portion is formed by a margin folded back towards the other free end (26) of the tongue (20).

Abstract: The can member (10) is provided with a pair of scorings (16) which define a tear-off strip (18) laterally. A tongue (20) produced as a separate sheet-metal part is welded onto the tear-off strip (18) in a welding zone (42) at one of its ends. Between the welding zone (42) and the free end (32) of the tongue (20), a starting scoring (30) extends over the tear-off strip (18) to within the vicinity of the two lateral scorings (16). The starting scoring (30) is part of a field (28) of a plurality of scorings formed on the tear-off strip (18) below the tongue (20). The welding zone (42) partially covers over this field (28). As a result, care is taken to ensure that a tearing open operation can be reliably initiated by rolling up the tongue, substantially regardless of inaccuracies in manufacture.

Abstract: For the welding of tongues (12) onto rupturable can members (10) of tin plate, a pair of welding electrodes (20, 22) is provided which are movable cyclically towards and away from one another and are additionally movable cyclically transversely to this movement in such a manner that successive spot welds are carried out by different portions of electrode.

Abstract: The apparatus described is so constructed that narrow can bodies having an internal diameter of 52 mm for example can be produced from rounded blanks by welding the edges of the blanks. The supply of welding current to the electrode roller is effected through copper caps, a clamping member, contact members disposed at each side thereof, contact jaws silver contact segments and peripheral surfaces of wide hubs which are provided on the electrode roller. The contact jaws engage the hubs of the electrode roller at both sides of the roller from above and below, as a result of which there is a large area for the transmission of current and a low specific contact pressure. The hub surfaces, which form the actual contact surfaces of the electrode roller, are continuously lubricated through felt lubricating segments. The contact pressure of the contact jaws can be adjusted in a simple manner by means of a screw.

Abstract: A can body is rolled from a sheet-metal blank (28) and has outer and inner longitudinal edges (12 and 14 respectively) which are welded to one another in an overlapping manner. Extending round the can body transversely to the longitudinal edges (12, 14) are two circumferential scorings (16) which define a tearing strip (18) laterally. The tearing strip (18) is extended by a tongue (20) which is welded onto the outer longitudinal edge (12) and which can be gripped by a key and rolled up. In a welding zone (42) which is adjacent to a starting scoring (30), the tearing strip (18) is stiffened by the welded-on tongue (20) in such a manner that it tears away from the can body reliably along the circumferential scorings (16) during the rolling up of the tongue (20).