| 摘要 |
In the production of bags from tube sections 2 provided with folded bases 1, wherein the sections are conveyed transversely (arrow 3) in a flattened condition but with the bases 1 at right-angles thereto, photocells 4 to 7 on one side of the bases 1 are disposed to scan parts of the edges or fold lines of the bases and are spaced apart so that, if the bases are formed correctly, light from a source on the other side is simultaneously blocked to all of them by the bases. The photocells are electrically connected to an AND element having the same number of inputs as there are photocells and the output of which defines a signal for eliminating tube sections with defective bases. In an alternative or additional embodiment, photocells are placed so that they are all illuminated with a correctly formed bag; similar and circuitry being used. <IMAGE> |
