APPARATUS FOR TRACKING A WEB

Abstract: An apparatus and method for automatically tracking a web of film fed through a packaging machine is provided. The apparatus includes a pair of photoelectric sensors (39, 41) located on a lateral side of the apparatus in juxtaposition to a first side (40) of the web of film. A pair of abutment members (43, 45) for abutting a side of the web of film are also provided. The abutment members are located on opposing sides of the web of film. The apparatus includes a member (59) for moving the abutment members in a first lateral direction or a second lateral direction to cause one of the abutment membersto contact a side of the web of film. A control circuit for actuating the member is provided. The photoelectric sensors are coupled to the control circuit and cause the control circuit to actuate the member for moving the abutment means if an edge of the first side of the web of film does not pass between the pair of photoelectric sensors.

Description: The present invention relates in general to tracking apparatus. More specifically, the present invention relates to an apparatus for automatically tracking a web of film in a packaging machine. An example of a packaging machine is a form, fill, seal packaging machine. Typically, form, fill, seal packaging machines are utilized to package a product in a flexible container. To this end, form, fill, seal packaging machines are used to seal pharmaceuticals, dairy products, wine, food stuffs, cosmetics, and other products in flexible containers. The form, fill, seal packaging machine provides an apparatus for packaging these products in an expedient manner. In one type of form, fill, seal packaging machine, a web of heat sealable film is passed over a former or mandrel that forms the film into a tubular shape. To effect the tubular shape, the film is folded longitudinally and heat sealed along abutting longitudinal edges (to create the fin seal). The tubular-shaped film is then passed around a tubular fill system that deposits the product to be packaged into the tubular-shaped film. To create individual packages (hereinafter "bags"), the web of film must be sealed along its width by side seals. The side seals are typically created by a sealer that creates the second side seal of one bag while making the first side seal for the next bag. After the side seals are created, the web of film can then be severed between the side seals to create individual bags. It may also be desirable, in some arts, to attach fitments to the web of film during the form, fill, seal process to create bags having fitments thereon. The fitments provide a means for accessing the contents of the container. An example of such a flexible bag is the VIAFLEX® container produced by Travenol Laboratories of Deerfield, Illinois. As previously stated, in order to create the flexible bags in the form, fill, seal packaging machine, a web of film is fed into the packaging machine. In order to ensure that an aesthetically pleasing and functional flexible bag is created, it is necessary to ensure that the web of film is properly oriented at the sealing and fitment attachment stations. Orientation of the film in the form, fill, seal packaging machine includes ensuring that the film is properly registered, i.e., is properly positioned lengthwise with respect to the form, fill, seal packaging machine and is properly tracked, i.e., is properly positioned along its width with respect to the form, fill, seal packaging machine. If the tracking of the web of film is not proper, the fitment position, side seals, and fin seal, of the resultant bag may not be proper. In tracking the film within the form, fill, seal packaging machine, to ensure that it is properly oriented, one must be concerned with the imperfections in the web of film. Commercially produced webs of film typically do not have perfectly straight parallel sides. Rather, the film may be skewed to the left or right or include minor imperfections. Accordingly, it may be necessary to compensate for the skew of the film during the processing of the film to ensure that it is properly oriented in the form, fill, seal packaging machine. However, in providing a tracking system for a form, fill, seal packaging machine, it is desirable to provide an automatic tracking system that does not slow down or hamper the construction of the flexible containers in the form, fill, seal packaging machine. Accordingly, there is a need for an improved tracking system for a form, fill, seal packaging machine. US-A-3711011 (Schopp) discloses an apparatus for detecting the position of a web fed therethrough using a pair of temperature sensing elements. A pair of abutment means located adjacent opposite lateral edges of the web are actuated to correct the tracking of the web in the event of web skewing being detected. US-A-3232547 (Thiede et al ) discloses an edge monitor device comprising a pair of photoelectric sensors for sensing the lateral position of a web fed through the device. Corrections for any deviation of the web tracking are made according to the sensed position by altering the lateral position of the web payout spool. A clamp and rod are provided for manually altering the lateral position of the sensors with respect to the web. The pre-characterising part of Claim 1 is based on US-A-3711001, and the distinguishing features of the present invention are set out in the characterising part of Claim 1. The present invention provides an apparatus for automatically tracking a web of film fed through a packaging machine. The apparatus includes a pair of photoelectric sensors, the photoelectric sensors are located on a lateral side of the apparatus in juxtaposition to an edge of a first lateral side of the web of film that is being fed through the packaging machine. The photoelectric sensors are staggered laterally with respect to each other. The apparatus also includes a pair of abutment means located on opposing sides of the web of film for abutting the sides of the web of film. The apparatus further includes means for moving the abutment means to cause one of the abutment means to contact a side of the web of film. A control means for actuating the means for moving the abutment means is also provided. The photoelectric sensors are coupled to the control means and cause the control means to actuate the means for moving the abutment means if an edge of the first side of the web of film does not pass between the pair of photoelectric sensors covering only one of the photoelectric sensors. Preferably, the control means is a control circuit. Preferably, the photoelectric sensors are secured to an eye bracket. Preferably, the eye bracket is secured to means for moving the eye bracket laterally. Preferably, the means for moving the eye bracket laterally includes a rotatable handle having a threaded rod. Preferably, each of the abutment means includes an abutment plate, and the abutment plates are secured together by a cross bar. Preferably, the means for moving the abutment means includes a piston that is actuated by a hydraulic-air system actuated by the control means. Accordingly, the present invention provides a means for automatically tracking a web of film through a form, fill, seal packaging machine. A still further advantage of the present invention is that it provides a nonintrusive means for tracking film in a form, fill, seal packaging machine. Moreover, a still further advantage of the present invention is that it provides an accurate means for tracking film through a form, fill, seal packaging machine. Still an advantage of the present invention is that it allows one to compensate for imperfections in the web of film in tracking the film through the form, fill, seal packaging machine. Additional features and advantages of the present invention are described in and will be apparent from the detailed description of the presently preferred embodiments and from the drawings. Figure 1 illustrates a cross-sectional perspective view of a form, fill, seal packaging machine including the tracking means of the present invention. Figure 2 illustrates a cross-sectional view of the tracking apparatus of the present invention. Figure 3 illustrates a top elevational view of the tracking apparatus of the present invention with parts broken away. Figure 4 illustrates a side elevational view of the tracking apparatus of the present invention. Figure 5 illustrates a top elevational view of a portion of the film tracking system tracking a web of film. Figure 6 illustrates a cross-sectional view of the photoelectric sensors and a web of film taken along lines VI-VI of Figure 5. Figure 7 illustrates a schematic of the air/hydraulic system for orienting a web of film in the tracking apparatus of the present invention. The present invention provides a tracking system for automatically tracking a web of film through a form, fill, seal packaging machine. As used herein the term ¨form, fill, seal packaging machine" refers to a machine for creating from a flexible web of film, a bag for housing a product. Of course, the tracking means of the present invention can be utilized in other packaging machines or in other apparatus where it is necessary to track a web of film as it is fed through an apparatus or system. In a typical form, fill, seal packaging machine, a web of heat sealable film is passed over a former that forms the film into a tubular shape. The film is folded longitudinally by the former and heat sealed along abutting longitudinal edges at a fin seal station (to create the fin seal). After the fin seal is created, a first side seal is created in the film, product is introduced into the tubular-shaped film, and a second side seal is then created; the film is then severed to create a flexible package. Referring now to Figure 1, a form, fill, seal packaging machine 10 is illustrated. As illustrated, the web of film 12 is fed into the packaging machine 10 through an opening 14. Once in the packaging machine 10, the web of film 12 is fed around a plurality of rollers 15, 16, 17, 18, and 20. Of course, although five rollers 15, 16, 17, 18, and 20 are illustrated, if desired, more or fewer rollers can be utilized. The film 12 is then fed to the tracking device 22 of the present invention. From the tracking device 22, the film 12 is fed to a former 24 that folds the film longitudinally so that longitudinal abutting edges of the film can be sealed at the fin seal station 26. The film 12 is passed around a fill tube 28 and side seals are created at the side seal station 30. If desired, fitments can be attached to the web of film 12 at a fitment attaching station. The film tracking device 22 of the present invention ensures that the web of film 12 is properly oriented at the sealing stations, i.e., the fin seal station 26, the side seal station 30, and fitment attachment station. This helps to ensure that a flexible bag having parallel side seals perpendicular to the fin seal is created. Likewise, it helps to ensure that the web of film 12 is folded longitudinally so that at the fin seal, the edges of the film are aligned. Furthermore, if fitments are attached to the web of film, the film tracking device 22 helps to ensure that the fitments extend from the bottom center of the resultant flexible container. Although the tracking device 22 is illustrated as being located in juxtaposition to the former 24, the tracking device 22 can be located at other positions before the former in the form, fill, seal packaging machine 10. In fact, if desired, the tracking device 22 can be located outside the form, fill, seal packaging machine 10 and can orient the web of film 12 before the film enters the opening 14 of the form, fill, seal packaging machine 10. It should be noted, however, that the further away from the fin and side sealing stations 26 and 30, respectively, the film tracking device 22 is located, the more difficult it will be to ensure that the film 12 is properly oriented at the sealing stations. Referring now to Figures 2-6, the film tracking device 22 of the present invention is illustrated. As illustrated in Figure 4, the web of film 12 enters the film tracking apparatus 22 by being received by a film guide 31. The film guide 31 comprises two plates 33 and 35 that define a channel 37 through which the web of film 12 is received in the film tracking device 22. The film guide 31 functions to track the web of film 12 and keep it from fluttering so that the film can be tracked from left to right in the tracking device 22. After the web of film 12 is fed through the film guide 31, it passes a sensing device 38. Preferably, the sensing device is a pair of photoelectric sensors 39 and 41. The photoelectric sensors 39 and 41 are located in juxtaposition to a first side 40 of the web of film 12. Preferably, the photoelectric sensors 39 and 41 are fiber optic eyes. However, any photoelectric sensing means known in the art can be utilized. As discussed below, the photoelectric sensors 39 and 41 function to allow the film tracking apparatus 22 to automatically align the web of film 12. After the web of film 12 passes the photoelectric sensors 39 and 41, it is fed between a pair of abutment plates 43 and 45. As illustrated in Figures 2, 3, and 5, located on either side of the web of film 12, as it is fed through the tracking device 22, are abutment plates 43 and 45. The abutment plates 43 and 45 function to track the web of film 12 through the form, fill, seal packaging machine 10. To this end, the abutment plates 43 and 45 function to trap the web of film 12 between the plates and urge the film either left or right. Accordingly, the abutment plates 43 and 45 are spaced apart from each other by a distance that is slightly greater than the width of the web of film 12. Preferably, the abutment plates 43 and 45 are spaced apart from each other at a width that is approximately 0.0025 mm (1/10,000 of an inch) to 6.25 mm (1/4 of an inch) greater than the width of the web of film 12. Of course, the more precise one desires to track the web of film 12 through the form, fill, seal packaging machine 10, the smaller the difference should be between the abutment plates 43 and 45 vis-a-vis the width of the web of film 12. The abutment plates 43 and 45 are secured together by a cross bar 47. The cross bar 47 causes the abutment plates 43 and 45 to move in unison ensuring that the web of film 12 is trapped therebetween. As stated above, the photoelectric sensors 39 and 41 function to allow the tracking device 22 to automatically track the web of film 12. To this end, the photoelectric sensors 39 and 41 are located, as illustrated in Figure 5, in a laterally staggered stacked relationship. To this end, the photoelectric sensors 39 and 41 are located so that they are slightly off center with respect to each other. The tracking device functions to center the first edge 48 of the web of film 12 between the photoelectric sensors 39 and 41 so that one photoelectric sensor 39 is covered by the web of film while the other photoelectric sensor 41 is not. As discussed in more detail below, if both photoelectric sensors 39 and 41 are covered, or if neither photoelectric sensor 39 and 41 is covered, the web of film12 will be moved by the film tracking device 22, and specifically the abutment plates 43 and 45, to correct the situation so that the first edge 48 of the web of film 12 will be located between the photoelectric sensors 39 and 41. As illustrated in Figure 3, the photoelectric sensors 39 and 41 are secured to an eye bracket 51. The eye bracket 51 is secured to a rotatable handle 53 that causes the eye bracket 51, and thereby the photoelectric sensors 39 and 41, to move laterally as the handle 53 is rotated. To this end, the rotatable handle 53 includes a threaded rod 55 that is secured to the eye bracket 51 and is received within a threaded aperture in the first abutment plate 43. Accordingly, when the handle is rotated either clockwise or counterclockwise, the eye bracket 51, and thereby the photoelectric sensors 39 and 41, will move either left or right with respect to the first side of the web of film 12. The rotatable handle 53 allows the operator to adjust the position of the photoelectric sensors 39 and 41. Accordingly, if one wants to move the web of film 12 to the left, the photoelectric sensors 39 and 41 can be moved so that the position of the web of film 12 will be adjusted as discussed in more detail below. The rotatable handle 53 therefore provides a means for physically positioning the photoelectric sensors 39 and 41 in a desired position. The photoelectric sensors 39 and 41 are coupled to a control circuit that actuates a piston 59 that causes the abutment plates 43 and 45 to move. To this end, if both photoelectric sensors 39 and 41 are covered by the web of film 12, and specifically the edge 48 of the first side of the web of film, the photoelectric sensors will cause the control circuit to actuate the piston 59 causing the piston to move the abutment plates 43 and 45 to move the film to the left. To this end, the abutment plates 43 and 45 move the web of film 12 as the first abutment plate 43 is urged against the right side of the web of film 12. Likewise, if both photoelectric sensors 39 and 41 are uncovered, the control circuit will cause the piston 59 to move the abutment plates 43 and 45 to the right causing the second abutment plate 45 to contact the left side 50 of the web of film 12 and thereby move the web of film 12 to the right. Accordingly, the control circuit and abutment plates 43 and 45 cooperate with the photoelectric sensors 39 and 41 to center the web of film 12 between the photoelectric sensors. The piston 59 can be an air cylinder. Preferably, the piston 59 is a hydraulic cylinder. As illustrated in Figure 7, preferably, an air/hydraulic system is utilized to move the tracking device 22 and accordingly, the web of film 12. Although air provides an economic means for actuating the abutment plates 43 and 45, to cause the web of film 12 to move, a simple air system would be too erratic. A total hydraulic system, however, is expensive. By using an air/hydraulic system, one is afforded the economics of air with the benefit of hydraulics. As illustrated, the web of film 12, as it passes through the tracking device 22, is fed around a pair of rollers 61 and 63. Preferably, the shafts 65 and 67 of the rollers 61 and 63, respectively, are fixed and the rollers rotate there around. The rollers 61 and 63 can be constructed of any material known in the art. Preferably, the rollers 61 and 63 are aluminum, stainless steel, or plastic. The construction of the rollers 61 and 63 will depend on particular requirements and whether the tracking device 22 is being used in an aseptic or nonaseptic packaging machine. Accordingly, the film tracking system 22 of the present invention provides a means for automatically tracking the web of film 12 through the form, fill, seal packaging machine 10 so that it is properly oriented. Once the operator sets the photoelectric sensors 39 and 41 in the proper position, the automatic tracking device 22 will ensure that the first edge 48 of the web of film 12 is oriented between the photoelectric sensors 39 and 41 covering only one photoelectric sensor 39. Therefore, once the photoelectric sensors 39 and 41 are properly oriented by the operator, the tracking of the web of film 12 through the packaging machine 10 will proceed automatically. As previously stated, typically, it is necessary to constantly compensate for a web of film's construction because a web of film 12 does not have perfectly parallel sides. The present invention, however, provides an automatic means for so compensating. Moreover, the tracking device 22 of the present invention allows the operator to manually compensate for variations of the web of film 12. If the web of film 12 is skewed to the left or right, the tracking device 22 allows the operator to compensate therefor. To this end, the operator can cause the film 12 to move the opposite way by repositioning the photoelectric sensors 39 and 41 so that by the time the web of film 12 reaches the sealing stations, i.e., fin seal, side seal, and fitment stations, the web of film is perfectly oriented.

Claims: An apparatus for automatically tracking a web of film (12) fed therethrough, comprising sensing means (39,41) located in juxtaposition to a first lateral side (40) of the web of film (12), a pair of abutment means (43,45) located adjacent opposing lateral edges of the web of film (12) for abutting opposite lateral edges of the web of film (12), first moving means for moving the abutment means (43,45) to cause one of the abutment means (43,45) to contact a lateral edge of the web of film (12), and control means for actuating the first moving means, the sensing means (39,41) being coupled to the control means, characterised in that the sensing means (39,41) comprises a pair of photoelectric sensors which causes the control means to actuate the first moving means if an edge of the first side (40) of the web of film (12) does not pass between the pair of photoelectric sensors (39,41) with the lateral side covering only one of the photoelectric sensors (39), and further characterised by positioning means (55) for locating the pair of photoelectric sensors (39,41) relative to the web of film (12) and adjustable during operation of the apparatus for moving the pair of photoelectric sensors (39,41) laterally with respect to the web of film (12), and a handle (53) attached to the positioning means (55) for effecting said adjustment. The apparatus of Claim 1 including: an eye bracket (51), the photoelectric sensors (39,41) being secured to the eye bracket (51); and the positioning means (55) being coupled to the eye bracket (51) to move the eye bracket (51) laterally. The apparatus of Claim 2 wherein the positioning means (55) includes a rotatable handle (53) coupled to a threaded rod (55). The apparatus of any preceding claim wherein each of the abutment means (43,45) includes an abutment plate, and the abutment plates are secured together by a cross bar (47). The apparatus of Claim 4 wherein the abutment plates 43,55 are spaced apart by a distance that is greater than the width of the web of film (12) by approximately 1/10000 (0.0025 mm) to about 1/4 of an inch (6.25 mm). The apparatus of any preceding claim wherein the means for moving the abutment means includes a piston (59) that is actuated by a hydraulic-air system actuated by the control means. The apparatus of any preceding claim wherein the photoelectric sensors (39,41) are stacked and staggered laterally. The apparatus of any preceding claim including a channel (37) defined by two plates (33,35) for channelling the web of film (12) into the tracking device (22).

Inventors: GRUDE, FREDERIC L., HUGHES, ROBERT T., POSEY, JOHN L., WOODS, DALLAS L.
Applicants: BAXTER INTERNATIONAL INC. (A DELAWARE CORPORATION)
Application year: 1988
Main classification: B65H23
IPC codes: B65B41, B65H23