Patent Grant
7963091
The present invention is directed to an improvement in an indexing vacuum-packaging machine. Examples of such conventional vacuum packaging machines are disclosed in applicant's U.S. Pat. Nos. 5,271,207 and 5,517,805, for example, which references are incorporated by reference herein.
In a conventional, indexing vacuum-packaging machine, a lower film-web is indexed using an indexing advancing mechanism for situating the transverse, multiple package-receptacles formed in the lower film-web at a forming station and then to a sealing or sealing/vacuum station, where the upper film for completing the packages is applied, and vacuum-sealed. At each station, a lower tool is raised toward an upper, stationary tool for performing the requisite tasks at the respective station. However, in all indexing vacuum-packaging machines, misalignment between the upper and lower films is inevitable, owing to the fact that the longitudinal length of the lower film, taken in the direction of the indexing, constituting the length of each finished vacuum-package, after the cutting at the final cutting station, is greater than the length of the upper-film portion constituted by the printed matter, which printed matter typically consists of a repeating pattern of the name of the product contained in the package, the weight and/or quantity thereof, bar code, unique designs, and the like. This length of the printed matter on the upper film is intentionally made shorter than the length of the lower-film package-length, in order that the upper film may be slightly stretched at the vacuum-sealing station, in order to form a tight vacuum seal.
The material from which the upper is made is flexible and stretchable, which allows of the stretching thereof. In a conventional vacuum-packaging machine, the upper film is stretched every indexing cycle by means of brakes applied to the upper film at the sealing station. However, it is not possible to stretch the upper film in such a precise manner as to ensure continuous and proper registration and alignment of the upper film with the lower film in both the longitudinal and transverse direction relative to the lower film. Thus, longitudinal mis-registration, as well as transverse misalignment, is inevitable. The amount of stretching of the upper film is controlled and determined by the use of a dedicated photocell mounted above the indexed upper film at the sealing station. This photocell typically detects one black target-box per indexing cycle imprinted on the upper film, as mentioned above. This one, black target-box is located longitudinally centrally of the printed matter, at the end of the portion of the repeating pattern constituting the upper film of the central or middle package of the multiple packages being formed simultaneously at the sealing station. This black box of the printed matter of the upper film is used to indicate the end of the printed matter for each indexing cycle, and, therefore, the end of the length of the upper film to be sealed to the lower film at the sealing station. The photocell uses this black target-box to ensure that longitudinal registration is maintained between the upper and lower films for each indexing cycle. Thus, when the photocell detects that black target-box during each indexing cycle, it outputs a signal to cause the braking mechanism at the sealing station to brake the upper film for a predetermined time period in order to stretch the upper film the requisite amount in order to increase the length of the portion of the upper film between the upper-film supply and the portion of the upper film sealingly connected to the lower film at the sealing station during the previous indexing cycle. Ideally, this braking will stretch the upper film the exact amount equivalent to the difference between the length of the lower film at the sealing station containing the multiple, transverse receptacles formed simultaneously by the indexing machine during each indexing cycle and the length of the printed matter on the upper film. However, in reality, this is not case. This is so, because the photocell used for detecting the black target-box does not typically have a high resolution, and will often detect other printed matter on the upper film and assume that it is the target box. Moreover, since application by the brakes every indexing cycle creates formidable and considerable forces and jerking of the entire machine, transverse, or lateral, shifting, or creeping, of the upper film occurs, thus causing lateral or transverse misalignment between the edges of the upper and lower films. Since there is only black target-box imprinted on the upper film for each indexing cycle, at the center position of the upper film constituting the center, or middle, package being formed during the indexing cycle, it often occurs that the photocell will not detect any printed matter at all during any indexing cycle, or will interpret other printed matter as being the target. Thus, that indexing cycle will produce ill-formed packages, necessitating the operator of the machine to stop the machine, to remove the contents of the packages formed during that indexing cycle, and to reset or re-align the upper film so that the photocell will again be able to detect a black target-box the next indexing cycle. This problem has led to considerable downtime of the packaging machine, and the concomitant loss of productivity.
Referring to
It is the primary objective of the present invention to provide an improved indexing packaging machine that will more accurately position and align or register the upper film relative to the lower film at the sealing station of a vacuum-packaging machine.
It is the primary objective of the present invention to provide such an improved vacuum-packaging machine in which is provided a video camera that replaces a conventional photocell, whereby the braking and concomitant stretching of the upper film at the sealing station need only be performed only every few indexing cycles, whereby shaking and jerking of the machine is negated as compared to a conventional vacuum-packaging machine.
It is the primary objective of the present invention to provide such an improved vacuum-packaging machine with video camera whereby any portion of the printed matter on the upper film may be used as a target image, or pattern identification, for determining when to brake the upper film for the subsequent stretching thereof, without having to rely solely upon the hithertofore-used one black target-box imprinted on the upper film between longitudinally-repeating patterns of the printed matter on the upper film, thus obviating the inherent drawbacks of prior-art vacuum-packaging machines associates with the use of the detection of only this one black target-box.
Toward these and other ends, the improved vacuum-packaging machine comprises a video camera mounted above a portion of the upper film at the sealing station between the supply of upper film and the portion of the upper film previously sealed to bottom film during the previous indexing cycle. The video camera is focused on a section of this portion of upper film at the sealing station for detecting a predetermined target area, or pattern identification, of printed matter imprinted on the upper surface-face of the upper film. This section to be detected may form any part of the printed matter, and is not limited to, and preferably not, the one black target-box located longitudinally centrally between each longitudinally repeating pattern of printed matter on the upper surface-face of the upper film. The image of this predetermined target image is digitally stored in software associated with the video camera apparatus, in order that an image detected by the video camera may be compared thereto in a continuous manner during each indexing cycle.
According to the present improved vacuum-packaging machine, with the upper film stationary at the sealing station between indexing cycles, when a target image-area has been detected, or identified, by the video camera apparatus and the software thereof, an output signal is generated to cause the braking mechanism of the vacuum-packaging machine at the sealing station to be actuated to brake the upper film thereat that will stretch the upper film an amount that is at least greater or equal to the difference between the length of the lower film at the sealing station containing the multiple, transverse receptacles formed simultaneously by the indexing machine during each indexing cycle—which length is equal to the length of each indexing cycle—and the longitudinal length of the transverse repeating patter of printed matter on the upper film. For a detection of a pattern-identification target every five indexing cycles, the upper film is stretched five times the value of the above-mentioned difference between the length of the lower film and the length of the transverse repeating pattern of the printed matter on the upper film. This frequency of detection of the target-area depends upon the value of this above-mentioned difference. For a relatively small value of this difference, the frequency of detection of the target-area may be as infrequent as once in twenty indexing cycles, thus ensuring infrequent application of the braking mechanism for stretching the film, and the concomitant considerable lessening or elimination of all jerking, shaking and vibrations of the machine during the braking operation, and the subsequent obviation of transverse or lateral misalignment of the upper film relative to the lower film, in contrast to a conventional vacuum-packaging machine utilizing a photocell that actuates the braking mechanism every indexing cycle.
The invention will be more readily understood with reference to the accompanying drawings, wherein:
Referring now to the drawings in greater detail, in
Referring now to
When the upper film is stationary at the sealing station between indexing cycles, and when an image-pattern identification 76, or target image-area, has been detected, identified, and matched against the reference template of the image stored in the memory of the video camera system 72, using the conventional software of the video camera system, an output signal is generated to cause the conventional braking mechanism (not shown) of the vacuum-packaging machine at the sealing station to be actuated to brake the upper film during the end of the next indexing cycle at the preset location and will stretch the upper film an amount that is greater than the difference between the length of the lower film at the sealing station containing the multiple, transverse receptacles formed simultaneously by the indexing machine during each indexing cycle—which length is equal to the length of each indexing cycle—and the longitudinal length of the transverse repeating patter of printed matter on the upper film. For a detection of a pattern-identification target every five indexing cycles, the upper film is stretched five times the value of the above-mentioned difference between the length of the lower film and the length of the transverse repeating pattern of the printed matter on the upper film. This frequency of detection of the target-area depends upon the value of this above-mentioned difference. For a relatively small value of this difference, the frequency of detection of the target-area may be as infrequent as once in twenty indexing cycles, thus ensuring infrequent application of the braking mechanism for stretching the film, and the concomitant considerable lessening or elimination of all jerking, shaking and vibrations of the machine during the braking operation, and the subsequent obviation of transverse or lateral misalignment of the upper film relative to the lower film, in contrast to a conventional vacuum-packaging machine utilizing a photocell that actuates the braking mechanism every indexing cycle.
The video camera system detects the predetermined pattern-identification target 76 on the upper face of the upper film at a frequency F equal to N indexing cycles, where F is a numeral greater than one representing the frequency of detection of a predetermined target 76 by the video camera system, and N is a numerical value greater than one, whereby the video camera system detects a predetermined pattern-identification target on a repeating pattern of printed matter of the portion of the upper face of the upper once every N indexing cycles. Upon the video camera's detection of the predetermined pattern-identification target 76, the software program of the video camera system produces an output signal for braking the upper film in order to stretch the portion of the upper film at the sealing station an approximate length L, where L is equal to Nd, where N is greater than one, and d is the difference between the length of an indexing cycle and the length of a repeating pattern of printed matter on the portion of the upper face of the upper film. As an example, N may be defined as: 25>N>1.
The software program of the video camera apparatus comprises a portion thereof that produces the output signal during the downward movement of the lower tool of the sealing station but before the end of the current cycle has occurred, which end of the current indexing cycle is defined as the tool's-down position of the lower tool of the sealing station. This portion of the software program actuates the machine's conventional braking mechanism to brake the upper film during the next indexing cycle, after the current indexing cycle.
The braking mechanism is actuated at the end of the indexing movement in order to stretch the portion of the upper film at the sealing station, that extends between the supply of upper film and the rearward sealed end of a transverse section of the upper film sealed to the corresponding end of the lower film during the current indexing cycle, an amount greater than the difference between the length of one indexing cycle and the length of a repeating pattern of printed matter on the portion of the upper face of the upper film that constitutes the upper sealing layer of a package being sealed at the sealing station, which length is taken in the longitudinal indexing direction. The stretching of the upper film at the sealing station is defined by the approximate length L, where L is equal to Nd, where N is said numeral greater than one, and d is above-mentioned difference between the length of one indexing cycle and the length of a repeating pattern of printed matter on the portion of the upper face of the upper film.
In the preferred embodiment, the software of the video camera system actuates the braking mechanism at the sealing station during the downward movement of the lower tool at the sealing station and before the end of the current indexing cycle has occurred, which end of the current indexing cycle is defined as the tool's-down position of the lower tool at the sealing station. Thus, in the preferred embodiment, the predetermined target on a repeating pattern of printed matter on the upper face of the upper film is detected by the video camera when the upper film is stationary at the sealing station between indexing cycles.
Referring now to
In the above-described steps, it has been assumed that the video camera system has not detected the target area that would have generated an output to the braking mechanism for causing the braking and stretching of the upper film, as describe hereinabove, for continually registering the upper and lower films together. Thus, the software also monitors the state of the braking signal or position (block 130) for the braking mechanism, which braking signal is controlled by the software of the video camera system. If no registration switch signal has been generated during the current indexing cycle, then in decision block 132 the answer is “NO”, and the brake of the braking mechanism is in its release-state (block 134), meaning that the upper film will be not stretched the next indexing cycle.
If, however, during any indexing cycle the camera were to detect the pattern-matching image, as described hereinabove, then it will actuate a braking a command, and described in detail hereinbelow, for causing the braking of the upper film via the braking mechanism for the film-supply of the sealing station. Assuming that the camera will detect the pattern-matching image of the target every twenty indexing cycles, meaning that the upper film is stretched by the braking mechanism twenty times the length “d”, where “d” is the difference between the length of an indexing cycle and the length of a repeating pattern of printed matter on the portion of the upper face of the upper film, as described hereinabove, then the software, in response to an output from the video camera system, will generate an actuating registration-switch signal to actuate the braking mechanism of the sealing station during the next indexing cycle every twenty indexing cycles. This generation of the output from the video camera system will cause the answer to decision block 132 to be “YES”, to thus cause a “latch brake” signal to be generated (decision block 136). Since there is a time lag between the actuating registration-switch signal of block 132 and the “latch brake” signal of block 136, decision block 136 first decides if the “latch-brake” signal has actually been generated. If the answer to decision block 136 is “NO”, the program proceeds to block 134, where the brake mechanism remains in its released state. If the answer to decision block 136 is “YES”, meaning that the brake-latch signal has been output, then the braking mechanism is activated (block 138), at a predetermined location before the end of the indexing movement and held in its activated state to establish sealing. As for the example given above, it will be held a time to allow for the upper film to be stretched twenty times the value of “d”. Decision block 140 determines when the timer has counted down, and after it has counted down, the program proceeds to release the brake (block 134), as described above.
It is noted that there is a time lag between the output from the video cameras after having detected the pattern-matching image of the target and the time that the brake is activated, owing to the time delay caused by the intermediaries of conventional relay and solenoid-switch equipment of the sealing station. This time delay is typically between 40-50 milliseconds. Therefore, the brake is applied from between 1¼ and 1½ inches before the end of the current indexing cycle. For the example given above, where the pattern-matching image of the target is detected every twenty cycles, the upper film will be stretched ¼ inch. This is calculated as follows. If the camera produces an output every twenty cycles, and stretches the upper film ¼ inch, then “d” equals ¼ inch divided by 20 equal 1/80 inch. Or, put another way, with a “d” of 1/80 inch, if one wants to stretch less frequently, say every twenty indexing cycles, then it must be stretched a total of ¼ inch every twenty cycles. After twenty cycles, the target image will again fall within the reference viewing frame of the camera to cause an output from the camera to activate the brake to again stretch the upper film ¼ inch. The smaller the value of “d” is, the less stretching required and the less stress and strain on machine and less vibration and jerking, which will thus prevent lateral misalignment of the upper film. That is, after twenty cycles, the line of misalignment between the end of the upper-film's printed matter and the end of the lower-film package increases 1/80 inch every cycle, and for twenty cycles that is ¼ inch, which is the amount the upper film is stretched during the 21st cycle. It is also noted that the target image need only be within the camera's reference viewing area of between 60-80% for the camera to produce an output to activate the brake.
The “pattern identification” routine of the video camera is shown in
There is also shown in the
It is noted that there is a time lag between the output from the video cameras after having detected the pattern-matching image of the target and the time that the brake is activated, owing to the time delay caused by the intermediaries of conventional relay and solenoid-switch equipment of the sealing station. This time delay is typically between 40-50 milliseconds. Therefore, the brake is applied from between 1¼ and 1½ inches before the end of the current indexing cycle. For the example given above, where the pattern-matching image of the target is detected every twenty cycles, the upper film will be stretched ¼ inch. This is calculated as follows. If the camera produces an output every twenty cycles, and stretches the upper film ¼ inch, then “d” equals ¼ inch divided by 20 equal 1/80 inch. Or, put another way, with a “d” of 1/80 inch, if one wants to stretch less frequently, say every twenty indexing cycles, then it must be stretched a total of ¼ inch every twenty cycles. After twenty cycles, the target image will again fall within the reference viewing frame of the camera to cause an output from the camera to activate the brake to again stretch the upper film ¼ inch. The smaller the value of “d” is, the less stretching required and the less stress and strain on machine and less vibration and jerking, which will thus prevent lateral misalignment of the upper film. That is, after twenty cycles, the line of misalignment between the end of the upper-film's printed matter and the end of the lower-film package increases 1/80 inch every cycle, and for twenty cycles that is ¼ inch, which is the amount the upper film is stretched during the 21st cycle. It is also noted that the target image need only be within the camera's reference viewing area of between 60-80% for the camera to produce an output to activate the brake.
It is noted that the target area may also be detected by the video camera while the upper film is in translation during indexing movement rather than when the upper film is stationary. Thus, the video camera may detect the target area in a repeatable location regardless of the stretch or not effected by the stretch.
While a specific embodiment of the invention has been shown and described, it is to be understood that numerous changes and modifications may be made therein without departing from the scope and spirit of the invention.
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| Number | Date | Country | |
|---|---|---|---|
| 20100112916 A1 | May 2010 | US |
