Apparatus for positioning receptacles of ferromagnetic material and having a welding seam

摘要

When receptacles (1) having a substantially cylindrical side wall and a welding seam extending in the direction of the axis are to be angulary positioned it is known to rotate the receptacle about the axis and detect the passage of the welding seam past a probe and thereafter stop the receptacle a predetermined number of degrees after the detection. Provided that the receptacle wall is of a ferromagnetic material and that there is a substantial material overlapping at the welding seam the detection can take place by means of a magnetic probe for measuring the material thickness. However this method can not be used if there is only a slide material overlapping at the welding seam. In this case the use of a magnetic probe (11) urged against the receptacle wall (1) by spring means is suggested. The effect is based on the fact that the tip (17) of the probe on passage of the welding seam loses contact with the receptacle wall whereby a comparatively great pulse is produced in the output signal of the probe, said pulse being used as an energizising signal for stopping means (6) for the receptacle (1).