Abstract: Device for the semiautomatic or fully automatic electric longitudinal-seam mash resistance welding of can bodies from overlapping, cut-to-size sheet-metal blanks rolled into sidewalls (20), with a guide arranged in front of the welding site for determining the lap width of the sidewall edges (21, 22) including resilient guide elements (32-34), whereby the sidewall edges (21, 22), when traveling toward the welding site, can be pressed against the bases (29, 30) of the groove of a Z-rail (13), and with a calibrating rim (40) arranged in the zone of the welding site, with such a construction of the guide means that the lap width of the sidewall edges (21, 22) at the welding site is at most six times the thickness of the can wall, and with wire electrodes (11) that can be pulled off a reel and are guided over electrode rollers (7, 9), these electrodes being fashioned as flat-wire electrodes (11) having a width exceeding the lap width of the sidewall edges (21, 22) at the welding site.

Abstract: In conventional methods for welding can bodies along their longitudinal seams, high frequency substantially rectangular a.c. currents are used for the welding current to avoid the problem of arcing found in d.c. welders. However, the high frequency a.c. current causes an undesirable degree of heating which produces eddy currents and necessitates cooling equipment. To overcome this problem, a method of producing can bodies welded along their longitudinal seam is provided in which the length of a half wave of the substantially rectangular welding current is matched in length and concurrent with the amount of time required for a can body to pass between the welding electrodes.

Abstract: A device for producing a bead on a circumference of a hollow cylinder seeks to minimize the risk of unwanted deformations of the hollow cylinder such as wrinkles or bulges which can result when an area of the hollow cylinder to be beaded is forced inward without support. In a preferred embodiment, the device of producing a bead on a hollow cylinder includes an internal tool and an external tool which can be adjusted in a controlled manner in the radial direction, the internal tool comprising a support mandrel and an inner ring which is adjacent to the supporting mandrel in the axial direction and is capable of being adjusted radially relative thereto, and the external tool includes an outer ring which surrounds the inner ring and a hold-down ring which is axially adjacent the outer ring and capable of being adjusted radially relative thereto.