Package making – With cover-adjunct application or formation – Adjunct comprising provision to secure cover
Reexamination Certificate
2000-01-24
2001-04-24
Vo, Peter (Department: 3721)
Package making
With cover-adjunct application or formation
Adjunct comprising provision to secure cover
C053S451000, C053S552000, C053S555000, C493S927000, C493S213000
Reexamination Certificate
active
06219993
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for applying a reclosable fastener strip to the continuous web of film on a form, fill and seal machine. There are two manufacturing methods for forming reclosable packages on form, fill and seal machines. In one method, the reclosable fastener strip extends parallel to the feed direction of the continuous web of film. In the second method, the reclosable fastener strip extends transverse to the feed direction of the continuous web of film. The present invention relates to the method in which the reclosable fastener strip extends transverse to the feed direction of the continuous web of film. It is important in forming rcclosablc packages using this method that the timing of the cross sealing-jaws be coordinated with the position at which the reclosable fastener strip was bonded to the continuous web of film. U.S. Pat. No. 4,655,862 discloses a mechanism for cutting, locating and securing a flexible plastic reclosable fastener strip across the longitudinal axis of the continuous web of film that is being used to create a package having a reclosable top.
U.S. Pat. No. 4,909,017 discloses a machine for making bags that have a reclosable fastener on a form, fill and seal machine. The bag forming process disclosed in this patent includes the step of securing a reclosable fastener strip to the film such that it extends transverse to the direction of film feed. In both U.S. Pat. Nos. 4,655,862 and 4,909,017, a continuous web of film is fed to the form, fill and seal machine from a film roll. Prior to reaching the form, fill and seal machine, a reclosable fastener strip is attached to the surface of the continuous web of film. The reclosable fastener strips are cut from a continuous ribbon of reclosable fastener material that is provided from a supply roll. The strip is guided to the lateral edge of the continuous web of film and then into a channel member that overlays the film. The use of a conventional cutting clement as suggested in these patents has the disadvantage that the knife blades dull quickly when used on machines that produce upward of a hundred packages per minute. Also, conventional cutting knives get contaminated and dull as a result of the cutting action. The use of conventional cutting knives produce a service problem for machines of this type. A reclosable fastener strip is cut from the continuous ribbon which is then positioned by the channel on the upper surface of the continuous web of film. The lower surface of the reclosable fastener strip is secured to the upper surface of the continuous web of film. These patents disclose systems that require a separate apparatus outside of the form, fill and seal machine for securing the reclosable fastener strip to the film. As a result, there is a long span of film extending from the location outside the form, fill and seal machine where the reclosable fastener strip was bonded to the film to the point where the continuous web of film encounters the forming shoulder.
The continuous web of film from which packages are manufactured is very thin and is difficult to control. For this reason, it is desirable to mount the separate device for bonding the reclosable fastener strip to the continuous web of film close to the form, fill and seal machine that they serve. In fact, they are mounted so close that they may interfere with the normal servicing of the form, fill and seal machine. The long span of continuous film utilized by these machines must be processed and coordinated to assure that the reclosable fastener strip is properly located with respect to where the cross seal of the bag is formed and to assure that it is not damaged as it is moved from the point where it is secured to the continuous web of film to the point where it encounters the forming shoulder.
In addition, these prior art machines must complete the feeding, severing to length and bonding of the segment of reclosable fastener strip to the film before this sequence for the next segment can begin. Thus, the speed of the form, fill and seal machine that has been retrofitted with the prior art machines disclosed in these prior art patents is very limited. Also, in the prior art machines, the two halves of the reclosable fastener strip are not positively interconnected and, thus, could separate from each other or shift relative to each other during the subsequent package forming procedure.
SUMMARY OF THE INVENTION
Applicant has provided a mechanism that advances a length of reclosable fastener material from a continuous supply to a rotor that is mounted adjacent to the film to which a reclosable fastener strip is to be bonded. The advanced length of reclosable fastener material is held on the rotor and then the cutter fuser mechanism is activated to cut a strip from the continuous supply. Before the cutter-fuser jaws begin opening, a flange of the strip of reclosable fastener material is clamped by a brake mechanism to prevent the strip from being pulled away by the opening jaws. The rotor is then rotated 180° to bring the reclosable fastener strip to the location at which it will be bonded to the film. A flange of the reclosable fastener strip is grasped and the rotor is rotated an additional small amount which serves to release the reclosable fastener strip from the rotor. The rotor is then rotated in the reverse direction to thus properly locate its edge to receive the next length of reclosable fastener material.
It is important, for two reasons, that the reclosable fastener material be cut and fused the instant that it is in its final position on the rotor. First, the cutting and fusing jaws are at a temperature that, if the reclosable fastener material is stationary between the open jaws for even a short period, the two halves of the reclosable fastener material could be distorted and stick to the die and create problems in targeting the rotor track for the next feed cycle. Second, if the reclosable fastener material stands stationary at the point at which it is positioned to be cut and fused, this stationary period is added to the cycle time for producing a package on the machine. Cycle time must be kept to a minimum to maximize machine production. Since the micro-processor activates the cutter-fuser, we know precisely when activation of the cutter-fuser occurs. However, after activation there is a time period required for the cutter-fuser jaws to become fully closed. It is important to determine what this time period is. Likewise, since the micro-processor activates the cutter-fuser mechanism to open the jaws, we know precisely when this activation occurs. If the rotor carrying the reclosable fastener strip is rotated before the cutter-fuser jaws begin to open, the just severed end of the reclosable fastener strip is still clamped between the closed jaws and proper rotation of the rotor could not occur.
A jaw position sensor has been provided to sense when the cutter-fuser jaws are fully closed and when they begin to open. The sensing device is directed at the edge of a link for one of the jaws. As the jaws are closing and the sensor recognizes the edge of the link, a signal is sent to the central processor indicating that the jaws are fully closed and the strip has been severed after a set duration time. Likewise, when the jaws start to open, the sensor that is directed to the edge of the link does not see the edge anymore and sends a signal indicating that the jaws are opening. Thus, a single sensing device is used to determine when the cutter-fuser jaws begin to open and when they are fully closed. This jaw position sensor provides the information necessary to sever and fuse the reclosable fastener material as soon as it has reached its final position on the rotor and to rotate the rotor as soon as the severed strip of reclosable fastener material has been released.
Immediately following the closing of the cutter-fuser jaws to sever the reclosable fastener material, the jaws are opened. Since the cutter-fuser jaws are heated, it is possible that some sticking of the r
Brinks Hofer Gilson & Lione
Huynh Louis K.
Triangle Package Machinery Company
Vo Peter
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