mutual spacing b of the columns 29 32 the shape of the double loops 6 a 6 b can deviate from the shape shown in fig1 the tube end starting from which the bending operation of a cm element is to proceed is fixed to the base plate 30 by means of a bearing 30 a fig7 the tube 2 is bent around the molded part 23 a with the aid of a guide roller 34 which is fastened to a lever 36 the lever 36 being plugged onto the upper end of the column 29 of molded parts 23 a and being capable of displacement in height after the tube 2 has been bent sufficiently around said molded part 23 a fig7 dashed and dotted a molded part 23 b is plugged onto the column 32 the lever 36 is likewise plugged on the top of column 32 and the tube 2 is then bent further in the other direction fig8 it is to be borne in mind in this operation that before it is bent further the tube 2 bears without any pressure against each newly plugged on molded part 23 or lies without any pressure in the.