Package making – Methods – Closing package or filled receptacle
Reexamination Certificate
1999-08-23
2001-01-09
Kim, Eugene (Department: 3721)
Package making
Methods
Closing package or filled receptacle
C053S373900, C053S284700, C053S570000, C198S626100
Reexamination Certificate
active
06170238
ABSTRACT:
This invention relates to packaging machinery and more particularly to a packaging machine with an improved film transport conveyor for and method of sealing packages especially packages relatively heavy and liquid products.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 4,969,310 issued Nov. 13, 1990 to Hershey Lerner et al. under the title Packaging Machine and Method and assigned to the assignee of this patent (the SP Patent) discloses and claims a packaging machine which has enjoyed commercial success.
While the machine of the SP Patent has been successful, a problem has been experienced in its closure section. The problem is that too frequently due to weight of the products there is slippage of bags relative to pairs of opposed belts used to transport bags through a heat sealer. In addition, slippage of the bag fronts relative to the backs occurs resulting in poor seal quality. Alternatively or additionally it is too often necessary to provide a conveyor or other support for bags as they are transported through the sealer.
SUMMARY OF THE INVENTION
With the machine of the present invention, the described bag slippage problems of the prior art and others are overcome and the need for conveyor support of bags as they pass through the sealer is eliminated.
The advantages of the present invention are accomplished through the use of novel and improved special belts which are effective substantially to prevent any product weight induced slippage of the bags relative to the belts. The novel belts are also effective to resist longitudinal movement of the face and back of each bag relative to one another and to the belts.
A pair of main transport belts are provided. The main transport belts have facing surfaces which, as they are extended in runs passing through the seal station, have external surfaces in facing closely spaced relationship. These runs form transport reaches which have longitudinally extending grooves that are preferably each in the shape of a squared “U” in cross section. In one test that has been conducted, grooves having a transverse dimension of approximately ⅛ inch and a depth of approximately {fraction (1/16)} inch were used.
In the same test, a holding belt which was circular in cross section and had a diameter of ⅛ inch was used. The holding belt was disposed in the groove of one of the main transport belts such that it had a reach extending between the transport reaches of the main transport belts. With this arrangement, the holding reach of the holding belt extended into each of the grooves in the facing surfaces. This test produced a bag gripping capability of the order of four times that of the prior commercially successful belts.
In use upstanding front and back lips of bags to be sealed are trapped between one of the transport reaches or runs and the holding run or reach with the lips being clamped between the holding reach and walls defining a mating groove in which they are disposed. With heavy products the trapped lips are pulled downwardly causing the holding reach to roll slightly and more tightly clamp the bag lips against the walls of the mating groove. Where very heavy products are present, the gripping of the holding reach can be enhanced by tapering the wall defining the base of the mating groove. Further, one or more additional holding belts may be utilized to provide still greater holding power.
With such a construction, bags containing relatively heavy products are transported through the seal station as the upstanding lips are sealed. The need for a supporting conveyor under the bags being transported through the seal station is eliminated.
A series of longitudinally aligned, juxtaposed and individually biased, pressure members act against, the transport reach of one of the main transport belts. With the now preferred construction, these pressure members bias the one main belt against the bags and the holding belt and thence against the transport reach of the other main belt to in turn bias the other main belt against a backup element. While this biasing maintains pressure on the holding belt and the bag tops further to secure the bags against load induced slippage as the bags are transported through the seal section, with the present invention this biasing is primarily for another purpose. That purpose is to assure surface engagement of the main transport belts with bag lips being sealed to prevent hot gases which effect such seals from getting between the belts. Accordingly while the belts are biased together the biasing forces are, as compared with prior arrangements, significantly reduced. This reduction in biasing force results in reduced drag on the belts as well as belt wear and power required to drive the belts.
Optionally, the gripping forces may be further enhanced by utilizing an improvement disclosed in the New SP Patent. Specifically, belt surfaces at locations spaced from the heat sources which engage film being transported may be coated with a glue and sand slurry with a polyethylene coating over the slurry.
In order to prevent excessive heating of bags passing through the sealing section and the sealing section belts, the heat source for effecting the seals is shifted away from loaded bags and the belts when the machine is stopped and moved to a location adjacent the bags when the bags are moving. Thus, a mechanism is provided for shifting the heat sealer from a seal forming position to a storage position and return in synchronism with cycling of the machine when in an intermittent mode or otherwise stopped.
Lips of the bags which project from the seal section conveyor belts are heated by a contiguous heat tube sealer having an elongate opening adjacent the path of bag lip travel. Heated air and radiation emanating from this sealer effect heat seals of the upstanding lips to complete a series of packages. An adjustment mechanism is provided to adjust the angular orientation of the heat tube sealer relative to the bags path of travel.
Accordingly, the objects of this invention are to provide novel and improved package sealing machine, an improved plastic transport conveyor and methods of transporting plastic film and sealing packages.
REFERENCES:
patent: 3610501 (1971-10-01), Wolfelsperger
patent: 3665673 (1972-05-01), Billet et al.
patent: 3887063 (1975-06-01), Villanueva et al.
patent: 4969310 (1990-11-01), Lerner et al.
patent: 5134833 (1992-08-01), Lern et al.
patent: 5187917 (1993-02-01), Mykleby
patent: 5722218 (1998-03-01), Lerner
Automated Packaging Systems, Inc.
Kim Eugene
Watts, Hoffmann, Fisher & Heinke Co. L.P.A.
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