Apparatus for automatically processing a slide fastener chain

An apparatus for automatically processing a slide fastener chain to which a sucession of fly strips is attached, comprising:

• (a) an intermittently operative feed unit for feeding the fastener chain longitudinally along a path;
• (b) a first cutting unit, disposed on the path upstream of said feed unit, for forming an element-free portion in the fastener chain while said feed unit is inoperative;
• (c) a second cutting unit, disposed on the path downstream of said feed unit, for severing the fastener chain transversely across the element-free portion while said feed unit is inoperative;
• (d) a measuring unit, independent of said drive unit and disposed on the path upstream of said first cutting unit, for producing a number of electrical signals, depending on the amount of the fastener chain having been fed through said measuring unit, said measuring unit comprising a pair of idler rollers which are corotatable as the fastener chain is fed by said feed unit and which produces a number of the electrical signals depending on the number of revolutions of one of the idler rollers;
• (e) a detector, disposed on the path between said first cutting unit and said measuring unit, for producing a signal pulse each time confronting ends of each adjacent pair of the successive fly strips arrive at said detector, said detector comprising a light source positioned on one side of the path of the fly strips, and a photoelectric transducer element positioned on the other side of the path of the fly strips for receiving the light passed through a space between confronting ends of an adjacent pair of the successive fly strips;
• and
• (f) a processing circuit having outputs for electrically controlling said cutting units separately, and having inputs electrically connected to said detector and said measuring unit for, upon receipt of one signal pulse from said detector, counting the electrical signals having been issued from said measuring unit, and for producing a first output signal, when the number of the counted electrical signals reaches a first predetermined value corresponding to the distance between said first cutting unit and said detector, to de-energize said feed unit and, at the same time, to energize said first cutting unit, and for thereafter counting additional electrical signals from said measuring unit, and for producing a second output signal, when the number of the counted electrical signals reaches a second predetermined value corresponding to the distance between said cutting units, to again de-energize said feed unit and to energize said second cutting unit.