Bag making machine sealer slitter apparatus
A bag making machine sealer slitter apparatus for transversely sealing together and severing two layers of a tubular web of thermoplastic resin film, thereby forming a bag wherein the sealer slitter apparatus essentially comprising a sealing mans having two opposing seal bars equipped with heaters and a severing means including a retractable, superheated cutting edge.A sealer slitter apparatus for a bag making machine operable to produce thermoplastic resin film bags, said sealer slitter apparatus comprising:sealing means for applying heat to and transversely sealing together two opposing layers of a tubular web of thermoplastic resin film, said sealing means including,at least one stationary lower seal bar positioned beneath and extending transversely across an intended path of travel of a tubular web of resin film, said at least one stationary lower seal bar comprising a U-shaped seal bar,at least one upper seal bar positioned above, mutually opposed to and in vertical alignment with said stationary lower seal bar, wherein a tubular web of thermoplastic resin film may be operably fed between said upper and said lower seal bars.
Aseal bar reciprocating mechanism operable to impart selective vertical motion to said upper seal bar toward and away from said stationary lower seal bar and operably provide contact with a tubular web of thermoplastic resin film between said upper and said lower seal bars,
A sealer slitter apparatus for a bag making machine operable to produce thermoplastic resin film bags as defined in claim 1 wherein said at least one stationary lower seal bar comprises: a U-shaped seal bar positioned beneath and extending transversely across a tubular web of thermoplastic resin film.This invention relates to a novel bag making machine sealer slitter apparatus. More specifically, this invention relates to a sealer slitter apparatus which transversely seals together and severs two layers of a tubular web of thermoplastic resin film, thereby forming a bag.
Thermoplastic resin bags, such as those used in supermarkets, convenience stores, etc. are produced from a long tubular web of thermoplastic synthetic resin film. The tubular web, which is unrolled from a spool, is intermittently fed into a bag making machine where heat is transversely applied to the web in order to form a weld seal between the two layers of the web. A cutting edge intersects and transversely severs the web adjacent the seal in order to complete formation of a bag.
The difficulties suggested in the preceeding are not intended to be exhaustive but rather are among many which may tend to reduce the effectiveness of and product quality associated with present bag making machine sealing and slitting devices. Other noteworthy problems may also exist; however, those presented above should be sufficient to demonstrate that sealing and slitting devices for bag making machines appearing in the past will admit to worthwhile improvement.It is therefore a general object of the invention to provide a novel bag making machine sealer slitter apparatus which will obviate or minimize difficulties of the type previously described.It is a specific object of the invention to provide a bag making machine sealer slitter apparatus which will minimize the frequency of interruption of a bag making operation.
The severing means includes a cutting edge heated by a heater within the cutting edge, which is positioned adjacent the movable upper seal bar. In order to remove the carbon by-product of the thermoplastic film which adheres to the cutting edge, the cutting edge is heated to a degree which allows for combustion and self removal of the carbon byproduct from the cutting edge. The temperature necessary to combust the carbon by-product is much greater than the operable temperature of the seal bars.The stationary lower seal bar may be configured as a single transverse bar or a pair of transverse bars which form a "U" shape. A single bar forms a transverse seal on one end of a bag, while a "U" shaped lower seal bar transversely seals both the top and bottom of sequential bags, forming what is commonly known as "T-shirt" bags. Mutually opposing movable upper seal bars descend toward and contact the stationary lower seal bar, melting the web held between the two bars and forming a transverse seal.
A preferred embodiment of the invention which is intended to accomplish at least some of the foregoing objects comprises a bag making machine having a novel sealing means .The upper seal bar is coated with a Teflon tape which is independently provided from the upper seal bar. The Teflon tape may be replaced as needed without removing the entire upper seal bar. The lower seal bar is coated with Teflon.In the "U" shaped seal bar configuration, the cutting edge is vertically recessed between the two upper movable seal bars. To maintain machine efficiency, the sealing and severing operations occur essentially simultaneously. Because the cutting edge is recessed above the movable seal bar, the cutting edge must descend toward the stationary lower seal bar faster than the movable upper seal bar. The sealing and severing means are therefore driven by separate reciprocating mechanisms. The reciprocating mechanisms include spring biased members which encourage vertical upward movement o upper seal bar and cutting edge.Guide plates are provided on inner lateral surfaces of the "U" shaped movable upper seal bars to insure that the cutting edge transversely severs the thermoplastic web substantially parallel to the transverse weld beads formed by the sealing means.
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