Abstract: A method and apparatus for registration of a seal to a perforation on a plastic bag include a drum for forming a seal on a continuous plastic film and a downstream perforator/cutting station for forming a perforation on the film with respect to the location of the seal. The perforation is properly registered to the seal by sensing the seal location directly, with a seal sensor located near the perforator/cutting station.

Abstract: An apparatus and method are provided for detecting a formation or change in the consistency of a moving sheet material. The apparatus includes a radiation source, a radiation receiver, a support base for the sheet material, and a signal processor for producing a signal in response to the detection of a formation in the material. The apparatus may be modified to include moving or stationary support bases, and may be further modified to include structure for automatically positioning the source and receiver to optimize the detection of formations.

Abstract: A method and apparatus for registration of a seal and perforation on a plastic bag include a drum for forming a seal on a continuous plastic film with respect to a registration mark on the film and a perforator/cutting station for forming a perforation on the film with respect to the location of the seal. This method and apparatus is used in a plastic bag making machine to produce bags of different lengths. A detector locates the registration mark printed on the film and the drum diameter may be adjusted to form the seal at a desired location on the film with respect to the registration mark. A seal detecting station locates the seal and a controller adjusts the speed of the perforator/cutting station to properly locate the perforation with respect to the seal and to maintain a desired skirt length.

Abstract: A plastic bag making machine includes a cylindrical drum with a variable diameter. A plurality of seal bars define the circumference of the drum, and are substantially parallel to the drum's rotational axis. The bags are made from a plastic film with registration marks that are detected by a detector disposed near the film. A detector also detects each revolution of the drum and an encoder provides signals indicative of the position of the film. A controller determines the distance phase of the registration marks and the rum size error. The drum diameter is adjusted in response to an output of the controller in such a way as to correct for both the initial drum size error, the initial phase error, and the phase error accumulated while the drum diameter is being corrected.

Abstract: A plastic bag making machine includes a cylindrical drum with a variable diameter. A plurality of seal bars define the circumference of the drum, and are substantially parallel to the drum's rotational axis. A controller determines the distance between registration marks on the film using the output of an encoder as a position signal, and adjusts the diameter of the drum in response to the determined distance. The controller also determines the position of the seal bars relative to the registration marks and adjusts the diameter of the drum in response to the relative position. A downstream device includes a perforation to seal registration controller with a registration control input. The controller provides a control signal to the registration control input in response to changes in the diameter of the drum.

Abstract: An apparatus and method are provided for detecting a formation or change in the consistency of a moving sheet material. The apparatus includes a radiation source, a radiation receiver, a support base for the sheet material, and a signal processor for producing a signal in response to the detection of a formation in the material. The apparatus may be modified to include moving or stationary support bases, and may be further modified to include structure for automatically positioning the source and receiver to optimize the detection of formations.

Abstract: The present invention is directed to a method and apparatus for winding bags. A winder in accordance with the present invention includes a dancer assembly for speed regulation, a haul-in assembly for receiving a film, and a tumbler assembly to receive the film from the haul-in assembly. The tumbler assembly increases the path length the film travels to either separate bags and/or to provide for interleaving.

Abstract: The present invention is directed to a method and apparatus for winding bags. A winder in accordance with the present invention includes a dancer assembly for speed regulation, a haul-in assembly for receiving a film, and a tumbler assembly to receive the film from the haul-in assembly. The tumbler assembly increases the path length the film travels to either separate bags and/or to provide for interleaving.

Abstract: The present invention is directed to a method and apparatus for winding bags. A winder in accordance with the present invention includes a dancer assembly for speed regulation, a haul-in assembly for receiving a film, and a tumbler assembly to receive the film from the haul-in assembly. The tumbler assembly increases the path length the film travels to either separate bags and/or to provide for interleaving.