Package making – With means responsive to a sensed condition – Concurrent control of contents and receptacle feeds
Reexamination Certificate
1999-07-14
2001-05-22
Sipos, John (Department: 3721)
Package making
With means responsive to a sensed condition
Concurrent control of contents and receptacle feeds
C053S074000, C053S502000, C053S551000
Reexamination Certificate
active
06233902
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a form-fill-seal packaging machine. More particularly, this invention relates to a control device for the longitudinal sealer of such a packaging machine.
Such a packaging machine of the so-called vertical pillow type transports an elongated thermoplastic bag-making material (the “film”) along the outer surface of a filling cylinder while bending it into a tubular form by means of a former and to seal the mutually overlapping side edges of the film by means of a longitudinal sealer and simultaneously both the top edge of the bag which has been filled and the bottom edge of the next bag to be filled by means of a transverse sealer. For the longitudinal sealing, a sealer employing a heat belt is commonly used.
A packaging machine of this type is usually operated without stopping except in the case of a trouble, transporting the film continuously. In the case of a packaging machine of the type forming a system with a weigher, the packaging machine serving as the “main” and the weigher serving as the “slave” such that the weigher will serve to supply articles to be packaged in response to a “ready” signal outputted from the packaging machine, the packaging machine may be designed to stop the transport of the film temporarily when no articles are supplied from the weigher for whatever reason and to remove the heater belt so as to separate it from the film. If no articles are supplied in the next cycle, however, the heater belt will heat the same portions of the film in preparation for the next packaging operation, thereby damaging the film and producing a defective bag.
If the mechanism for transporting the film and the heater belt are controlled so as to be activated together, however, the longitudinal sealing will not be effected sufficiently on the beginning portion of the film, again producing a defective bag which can easily break after transversely sealed.
SUMMARY OF THE INVENTION
It is therefore an object of this invention, in view of the problems described above, to provide an improved packaging machine which will not produce any defective package even when it is reactivated after the supply of articles is once stopped and then restarted.
A packaging machine embodying this invention, with which the above and other objects can be accomplished, may be characterized as having a control unit adapted to control the operations of the packaging machine as a whole such that the longitudinal sealer is operated for a specified period of time when a first ready signal is outputted to the weigher and the mechanism for the film transport and the transverse sealers are activated after waiting until a signal is received from the weigher, indicating that a discharge of articles has been completed. With a packaging machine thus structured, longitudinal sealing is carried out for a specified length of time required for the type of film being used when a ready signal is outputted to the weigher to request a discharge of articles to be packaged, but the operations of the mechanisms for advancing the film and transverse sealing are started only after a signal is received from the weigher, indicating that the requested discharge of articles has been carried out.
The invention provides packaging machines with the advantage that properly sealed bags can be produced even after the weigher failed to discharge articles to be packaged.
REFERENCES:
patent: 3397505 (1968-08-01), Critchell
patent: 4018029 (1977-04-01), Safranski et al.
patent: 4023327 (1977-05-01), Simmons
patent: 4128985 (1978-12-01), Simmons
patent: 4597240 (1986-07-01), Scully
patent: 5743066 (1998-04-01), Fukuda et al.
patent: 0449551 (1991-03-01), None
Coudert Brothers
Ishida Co. Ltd.
Sipos John
LandOfFree
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