MXPA00002162A - Apparatus and method for sealing the open ends of a stream of packages - Google Patents

Abstract

A method and apparatus for successively sealing open ends of a plurality of packages being conveyed in series along an infeed lane is provided. A sealing station aligned with the infeed lane (20) for receiving the packages to be sealed is employed. A first package (10C) is transported from the infeed lane to the sealing station, the open end of the first package is engaged for sealing operations, and this engagement is maintained for a minimum sealing time while a second package is transported from the infeed lane to the sealing station. The open end of the second package (10D) is engaged for sealing operations, and the engagement is maintained for the minimum desired sealing time while a subsequent package is transported to the sealing station. These steps may then be repeated for subsequent packages. A plurality of sealing rigs moveable between receiving and holding positions may be employed for sealing operations.

Description

APPARATUS AND METHOD FOR SEALING THE OPEN END OF A PACKET STREAM FIELD OF THE INVENTION The present invention relates to a method for sealing packages, as well as an apparatus for the same. More particularly, the present invention provides a sealing apparatus and method that utilizes a plurality of sealing mechanisms in order to increase packet flow rates.

BACKGROUND OF THE INVENTION Most products are packaged in external packages before shipment to consumers and other end users. The packaging stage is usually an integral part of the production process, and can be a limiting factor in maximizing continuous placement. Therefore, it is generally advantageous to optimize the speed and efficiency of that packing step as much as possible, without adversely affecting the quality of the product. Typically, the products are inserted into a package comprising a bag, box, or other appropriately sized container, and this container is then sealed in order to isolate the product from the environment. These containers can be sealed by any of a number of means, including various types of adhesives and / or heat sealing. Heat sealing is achieved by welding one part of the container to another (for example, heat welding the opposite edges of a plastic bag to each other). This sealing step, however, is often not conducive to continuous manufacturing processes, since the sealing step requires the application of pressure and / or heat for a minimum period of time in order to effect proper sealing. This sealing time is significant, since the containers must either be stopped in the sealing device for a minimum period of time, or the sealing device itself must be able to move with the current of the packages. The above alternative may interrupt the flow of the product within the manufacturing process, while the latter may be expensive to implement. By way of example, consumer products such as diapers are typically packaged in an outer package comprising a flexible film bag (such as polyethylene or polypropylene). The diapers are inserted through the open end of the bag, the opposite sides of the open end portion of the bag are folded inward, and the opposite upper and lower flaps at the open end of the bag are then fixed to each other at to seal the diaper bag. Typically the opposing fins are melted together by the application of heat, with or without the use of additional adhesives such as glues and the like. A pair of sealing jaws are closed around the opposite fins in order to melt the fins together. These sealing jaws generally provide sufficient heat and pressure to melt or weld the opposing film fins to each other. The sealing jaws should be closed around the fins for a minimum time of coupling, however, to ensure sufficient transfer of energy for a fusion of the materials. Therefore, in order to achieve higher sealing speeds, and therefore a continuous higher product placement, the product streams are often divided into multiple transit lanes for the supply of the bagged products to the multiple devices of sealed. The division of the product stream into multiple traffic lanes is problematic because the straight-line path of the bag loading station to the sealing device is no longer maintained, and control of the end flaps can be lost unless they use additional control mechanisms. Taking additional steps to ensure that the product inside the bags or containers will not be dislodged or to maintain control of the extreme fins, however, generally entails additional costs, and the division of the product stream into multiple transit lanes for sealing the package requires additional floor space within the manufacturing facility. Alternatively, more expensive packaging materials may be used where these materials have fusion properties that require shorter coupling time for the sealing jaws. Thus, there is a need for an improved apparatus and method for sealing a stream of packages wherein multiple feed rails to the sealing devices are not needed, and conventional packaging materials may be employed.

BRIEF DESCRIPTION OF THE INVENTION It is an object of the present invention to provide a method and apparatus for sealing a stream of packages, wherein a plurality of sealing mechanisms are employed in order to increase product flow rates. It is another object of the present invention to provide a method and apparatus for sealing a stream of packages employing double sealing mechanisms, wherein the packages are not moved away from their straight line trajectory until after the start of the sealed. It is still another object of the present invention to provide a method and apparatus for sealing a stream of packages employing double sealing mechanisms, wherein each sealing mechanism is capable of moving between a receiving position aligned with the forward transit rail radial for the packages, and the holding position to complete the sealing step. The above objects can be achieved, according to one aspect of the present invention, by providing a method for successively sealing the open ends of a plurality of packages that is transported in series along a radially advancing transit rail, where the open end must be retained in its sealed condition for a certain minimum sealing time. This method comprises the steps of: a) providing a sealing station aligned with the radial advancing transit rail to receive the packages to be sealed; b) transporting a first package from the radial advance transit lane to the sealing station; c) coupling the open end of the first package in the sealing station for the sealing operations: d) maintaining the coupling of the first package during the minimum sealing time to seal its open end while transporting a second package from the sealing rail. transit of radial advance to the sealing station; e) coupling the open end of the second package in the sealing station for the sealing operations; f) maintaining the coupling of the second package during the minimum sealing time to seal its open end while transporting a subsequent package from the radial advancing transit rail to the sealing station; and g) repeating steps (b) - (f) as desired for subsequent packages to allow sealing of a plurality of packages moving along the radial feed rail to be sealed. The above method preferably employs one or more sealing mechanisms, and thus this method can further comprise the step of alternatingly moving a first sealing mechanism between the aligned receiving position with the radially advancing transit rail in the sealing station for receiving packages to be sealed, and a holding position for maintaining the coupling of the packages for sealing operations. A second sealing mechanism can also be provided, and in this way the method further includes the step of alternatingly moving a second sealing mechanism between a receiving position aligned with the radial advancing transit rail at the sealing station for receiving the packages to be sealed, and a holding position for maintaining the coupling of the packages for the sealing operations, wherein the first and second sealing mechanisms are aligned alternately with the radial advancing transit rail. In order to provide the appropriate sealing time while allowing a subsequent package to be sealed, the method of the present invention may further comprise the step of moving the first package out of alignment with the radially advancing transit rail during at least a part of the stage of maintaining the coupling of the first package. This can be achieved by moving the first sealing mechanism, with the first package kept there, towards its position of t retention which is out of alignment with the radial advance transit lane. Preferably, both sealing mechanisms move alternately in this manner. The open end of a package must be engaged prior to the movement of the package out of alignment with the radial advance transit lane in order to ensure that neither the package nor its contents will be dislodged. The first and second sealing mechanisms are also preferably linked to one another such that the step of moving one of the mechanisms towards its detent position occurs simultaneously with the step of moving the other sealing mechanism towards its receiving position, and in this way the second sealing mechanism can even be placed directly above the first sealing mechanism. Each of the sealing mechanisms preferably comprises a pair of opposed welding jaws capable of moving between the open and closed positions, such that the step of coupling the open end of a package comprises closing the jaws around the open end. . Each of the sealing mechanisms further comprises a package holder for retaining a package thereon as the sealing mechanism moves to its detent position and is returned to its receiving position. The sealed packages must also be released from the sealing station, and the step of transporting a subsequent package to be sealed in the sealing station preferably aids in the release of a sealed package therefrom. An apparatus for performing the above method is also provided. The apparatus comprises: a) a sealing station aligned with the radially advancing transit lane; b) a plurality of sealing mechanisms for coupling the open end of a package and maintaining the coupling; and c) an alternating mechanism adjacent to the sealing station which selectively moves each sealing mechanism between a receiving position aligned with the radial advancing transit rail at the sealing station, and a holding position which is not immediately aligned with the radially advancing transit rail and allows another sealing mechanism to be aligned with the radially advancing transit rail. Preferably, first and second sealing mechanisms are provided, and these mechanisms are linked to each other such that one of the stations is in its detent position when the other station is in its receiving position. More preferably, the first and second sealing mechanisms are connected to each other in such a way that the mechanisms can be moved concurrently with respect to each other. In fact, the retention position of the second sealing mechanism can be located above the plane of the radially advancing transit rail, with the retention position of the first sealing mechanism located below the plane of the radially advancing transit rail. Each of the sealing mechanisms comprises a package support for retaining a package thereon, and a sealing mechanism for sealing the package. This sealing mechanism may comprise a pair of welding jaws capable of moving between the open and closed positions, wherein the open end of a package may be sealed by closing the jaws around the open end. The apparatus of the present invention further preferably comprises an exit feed passage rail for the sealed packages released from the sealing mechanisms. The radially advancing transit rail, the forward advancing transit rail and the receiving position of each of the sealing mechanisms can therefore be aligned with each other, such that a package to be sealed it can be transported from the radially advancing transit lane towards a sealing mechanism located in its receiving position, and a sealed package can be unloaded from the sealing mechanism located in its receiving position on the advancing transit rail. departure.

BRIEF DESCRIPTION OF THE DRAWINGS Although the description concludes with the claims pointing out in a particular manner and claiming differently the present invention, it is believed that it will be better understood from the reading of the following description in combination with the accompanying drawings, in which: Figure 1 is a schematic illustration of the apparatus of the present invention; Figure 2 is an enlarged view of the dual sealing mechanisms of Figure 1; and Figure 3 is a schematic illustration of the apparatus of the present invention at the point at the time subsequent to that of Figures 1 and 2.

DESCRIPTION OF THE PREFERRED MODALITIES Referring now to the drawings in detail, where similar numbers indicate similar elements in all views, Figure 1 illustrates the sealing apparatus of the present invention. As will be described more fully here, this apparatus can be used to successively seal the open ends of a stream of packages 10A-F of which are being transported through a radially advancing transit rail 20 in series. By way of example, packages 10A-F may comprise diaper bags, incontinence pads or other consumer items. However, the present invention is not limited to the sealing of diaper packs, since the apparatus and method of the present invention can be used to seal any of a number of different pack types. The series of packages to be sealed are advanced along the radial advance transit rail 20 by any of a number of conventional means. In the example shown in Figure 1, push rods 15 are employed for this purpose, and these push rods are well known in the art. A chain drive or other advancing means moves the push rods in the desired direction, and these push rods in turn advance the packs along the radial feed rail 20 toward the sealing station. Each push rod 15 also has an end plate 16 which is positioned within the open end of each package in order not only to prevent the contents from being dislodged, but also to ensure that the end flaps remain open and controlled. HE. they can employ various other means for advancing the packages, however, such as conventional conveyor belts and the like. Therefore, the present invention is limited to the use of the push rods for advancing the packet stream along the radial feed rail 20. The radial feed rail 20 is downstream of the manufacturing apparatus and filling of packages and in this way each of the packages advances along the radial advance transit rail 20 that have already been filled with their respective products or products. Since the open end of each package has not yet been sealed, for many products it is critical that the package be moved as evenly as possible before sealing the fins. The change or changes in the direction of movement may cause a loss of control of the fins. For example, the division of the radial advance transit rail 20 in order to feed the packages to multiple sealing devices can cause the extreme fins of the packages to crush. This is particularly true for flexible, thin film packaging materials, which are commonly used to pack consumer products such as diapers, incontinence pads and sanitary napkins. In this way, the present invention is particularly suitable for sealing packages containing these types of products. In a conventional sealing apparatus, the packet stream would be deposited in an individual sealing device, one package at a time. After the package is properly placed in the sealing device, a pair of mechanical benders bend the opposite sides of the open end inward toward each other. A stop of welding jaws are then closed around the upper and lower fins of the package in order to seal the closed end. However, the welding jaws must remain in a closed position for a certain minimum sealing time in order to ensure proper sealing. Obviously, this prevents the introduction of a new package into the sealing device until the predetermined cycle of time for sealing has expired, thus decreasing the speed of the package seal. In fact, this conventional method of the individual sealing device is often a step limiting the speed in the overall production / packaging process. The present invention overcomes these deficiencies by providing multiple sealing mechanisms wherein a new package can be introduced into a second sealing mechanism while the welding jaws of a first sealing mechanism are in the closed position for the minimum period of time required. To achieve this, each sealing mechanism is moved out of the flow path of the product during the period of time in which the welding jaws are closed (ie, the sealing time). Simultaneously a new sealing mechanism is moved into the flow path of the product in order to accept a new package for sealing.

Switching to Figures 1 to 3, which represent the sealing apparatus and the method of the present invention, the stream of the packages 10 is advanced along the radially advancing transit rail 20 towards the sealing station. The sealing station is defined as the region between the radial advancing transit rail 20 and the forward advancing transit rail 30 which is aligned with the radial advancing transit rail 20. The packages to be sealed are transported from the radial advance transit lane to the sealing station, where the sealing operation of the package begins. It should be noted that a portion of the radial advance transit rail 20 has been cut out in Figures 1 and 3 in order to more clearly show the apparatus of the present invention. In the embodiment shown, first and second sealing mechanism 41 and 42 are provided, respectively, and each of these mechanisms may have conventional sealing mechanisms commonly employed to seal packages. As will be described more fully below, each sealing mechanism or equipment is capable of moving between a receiver position of the package aligned with the radially advancing transit rail at the sealing station, and a packet holding position. The sealing mechanisms are preferably linked to each other in such a way that they move in agreement between their reception and retention positions. Each sealing mechanism or equipment generally comprises a package support (platform 51 and 52) for retaining a package thereon, and a sealing mechanism for sealing the packages. Preferably, each sealing mechanism comprises a pair of opposed welding jaws capable of moving between the open and closed positions, wherein these welding jaws can close around the open end of a package in order to seal the package. These welding jaws are well known in the art, and can use heat and / or pressure in order to seal the end flaps. Various other types of sealing mechanisms known in the art may be employed with the present invention, however, and in this manner the present invention is limited to the use of opposed welding jaws. For example, ultrasonic microwave or mechanical pleating devices can be used to seal the fins. In the embodiment shown in Figures 1 to 3, the first sealing equipment or mechanism 41 has a package support platform 51, as well as upper and lower welding jaws 61 A and 61 B, respectively. Also, the second sealing equipment or mechanism 42 comprises a support platform 52, and upper and lower welding jaws 62A and 62B. Both sets of welding jaws are capable of moving between the open position and the closed position. Therefore, in the embodiment of Figures 1 and 2, the welding jaws 61 A and 61 B are in their closed, or non-operating position, while the welding jaws 62A and 62B are in their open position. In Figure 3, the welding jaws 61 A and 61 B are in their open position, while the welding jaws 62A and 62B are in their closed position. The movement of the welding jaws between their open and closed positions can be achieved by any of a number of conventional means, including a rack drive system, air cylinders or servomotors. In the example shown, a pair of pulley wheels 74 is provided on each side of each pair of welding jaws. A chain 64 is then secured around each pair of adjacent pulley wheels, and then servomotors or other means are provided for turning at least one of the pulley wheels. It should be noted that the servomotor, as well as the teeth on the pulley wheels which mesh the chain are not shown for purposes of clarity. Each of the welding jaws is then secured to opposite sides of the chain 64 as shown, and in this way when the pulley wheel 74 is rotated the sealing jaws will move in either toward each other or away from each other. For example, as shown in Figure 2, when the pulley wheels 74 associated with the welding jaws 61 A and 61 B are rotated in a clockwise direction, the welding jaws will be moved one toward the other. another (that is, towards its closed position). Various other alternatives can be used to move the welding jaws between their open and closed positions and thus the mechanism shown is only one possible mode. As also shown in Figure 2, in order to provide a folded closure of the open end of a package, a pair of mechanical benders is provided. Although a pair of benders may be provided for each sealing mechanism or equipment, in the embodiment of FIG. 2, only one set of fixed benders 66 is provided. In order to effect the sealing of the packages, the open end of package between the open welding jaws of a sealing equipment. For example, the open end of the package 10D is placed between the welding jaws 61 A and 61 B in Figure 2. The end plate 16 of each push rod 15 will ensure that the end of the bag (i.e., the end flaps) ) will not crush before the bag 10D is placed in the sealing equipment as shown in Figure 2. The mechanical benders 66 are each capable of moving between a retracted position (shown in Figure 2) and the extended position in where the triangular shaped head of each bender will bend the opposite sides of the bag with open ends facing each other. Once the sides are bent inward, the welding jaws 61 A and 61 B are then moved to their closed position thereby bringing the upper and lower end flaps 11 and 12 in contact with each other. In Figure 2, the welding jaws 62A and 62B are in their closed position around the end flaps of the package 10C. It should be noted that the triangular shaped head of the benders shown is only a preferred embodiment, and that alternative shapes can be employed. In addition, the benders are preferably moved into their retracted position as the welding jaws 61 A and 61 B close around the fins 11 and 12. Once the welding jaws are closed, they are held in this closed position. for a certain minimum period of time in order to properly seal the fins to each other. Although the end flaps of the package can be provided with a pressure sensitive adhesive, it is preferred that heat sealable materials be employed. In this way, the welding jaws are heated preferably. In this way, when closing the welding jaws around the end flaps, the heat provided by the welding jaws (as well as the pressure of the jaws) will seal the end flaps to each other by means of heat sealable heat. In order to provide a thermally sealable material, the open end of the bag (or at least the end flaps) can be made of a suitable polymeric material having a melting point below the temperature of the welding jaws. Alternatively, strips or other discrete regions of thermally sealable material may be provided on the end flaps. The heat seal can also be used in combination with conventional adhesives such as various glues and the like to provide an even stronger seal. In some examples, # only conventional adhesives can be used. Switching now to the process shown in Figure 1, the first sealing equipment 41 is located in its receiving position of the package in the sealing station, aligned with the radial advancement transit rail 20. The second sealing equipment 42 is in its retention position of the package (with the package 10C kept on it). The package 10D to be sealed has been placed on the support platform 51 of the first equipment or sealing mechanism 41. When a sealing device or mechanism is in its receiving position of the package, the welding jaws are open and the benders are retracted, thus allowing a package to be placed in there to seal. Preferably, a package leaves the radial advancing transit rail 20 and passes between the open welding jaws until it lies on the support platform. The package should be placed on the support platform in such a way that the open end of the package is placed between the open welding jaws. This alignment can be ensured by any of a number of means, including control of the movement of the packages along the radially advancing transit rail 20. Alternatively (or additionally), a stop can be placed on the platform of support to prevent movement of the package beyond a certain predetermined location. After the 10D package has been properly positioned on the support platform 51, the open end of the package is engaged for sealing operations. In this way, the benders 66 are extended in order to fold the sides, and then the welding jaws 61 A and 61 B are closed around the upper and lower end flaps (11 and 12 in Figure 2) in order to start the seal. At this point, the welding jaws not only act to seal the end flaps, but also retain the package and its contents on the support platform 51. In this way, the first equipment or sealing mechanism 41 can now be moved without the risk of dislodging the contents of the package 10. After the welding jaws 61 A and 6 1 B have been closed around the end flaps (ie, the coupling of the open end of the package), the equipment or mechanism of the sealing 41 towards its pack retainer position (shown in Figure 3). In the preferred embodiment shown, the first sealing mechanism 41 moves down relative to the radially advancing transit rail plane 20. Although vertical movement of the sealing mechanisms is preferred, the sealing mechanism 41 can also be moved towards the left or right of the radial advancement transit rail 20, diagonally away from the radial advancement transit rail 20, or even in a turnaround manner. Therefore, the sealing mechanism 41 should only be moved away from the flow path of the product, out of alignment with the radially advancing transit rail, in order to allow placement of the second sealing mechanism 42 to receive The next package to be sealed. The sealing mechanism 41, with the package 10D retained or the same, must remain in the retention position of the package for a predetermined period of time, while maintaining the coupling of the end that is sealed. In this way, proper sealing of the open end of the package is obtained. Since the sealing process begins as soon as the welding jaws close, however, it is not necessary for the sealing mechanism 41 to remain in its holding position for the total time necessary for proper sealing. The total period of time that the welding jaws remain closed around the extreme fins is the determining factor. However, unlike the methods and apparatuses of the prior art, as the sealing mechanism 41 moves away from the sealing station towards its retention position of the package (Figure 3), the second sealing mechanism is moved 42 to its receiving position of the package. In this way, as shown in Figure 3, the second sealing mechanism 42 has now moved towards its receiving position of the package aligned with the radial advancing transit rail 20 at the sealing station. The package 10E to be sealed can now advance from the radial advance transit rail 20 on the support platform 52 in the manner described above for the package 10D. Thus, the open end of the package 10E is placed between the open welding jaws 62A and 62B of the second sealing mechanism 42. Subsequently, the benders 66 can extend to fold the sides of the open end, and then the welding jaws 62A and 62B can Close around the extreme fins of the 10E pack to begin the sealing process. Once the welding jaws 62A and 62B are closed around the end vanes, the second sealing mechanism 42 can be returned to its retention position of the package shown in Figure 1. In the preferred embodiment, the retention position of the The package for the second sealing mechanism 42 is located above the plane of the radially advancing transit rail 20. However, once again, the most important aspect is that the second sealing mechanism 42 is moved away from the path of the second sealing mechanism 42. product flow (defined by the radial advance transit lane 20 and the exit advance transit lane 30) and therefore the sealing mechanism 42 can be moved laterally, diagonally, or in a return manner (i.e. , similar to the movement of a ferry wheel). As the second sealing mechanism 42 moves to its pack retaining position, the first sealing mechanism 41 is returned to its receiving position of the package at the sealing station, the welding jaws are opened, the 10D package (which has now been sealed) is released from the sealing station, and is allowed to travel via the outbound transit transit lane 30. A new package is then deposited to be sealed (10F) on the support platform 51. The total process can be repeated in a continuous manner in order to seal a stream of packages entering the sealing apparatus of the present invention. The timing of the previous steps is such that the welding jaws remain closed around the open end (ie, the end flaps) for the same minimum period of time as in the prior art, thus providing an equivalent seal for the package. Because the packet retention step is performed outside the flow path of the product stream, however, the total flow rate of the packets is greatly improved. With conventional sealing apparatuses, the individual sealing device is paralyzed for the duration of the sealing step, and therefore can not accept additional packages until the sealing step has been completed. The apparatus and method of the present invention, however, provides access to a second sealing mechanism during the time-consuming sealing process. This new process and apparatus is also an improvement over the division of the radial advance transit lanes since less installation floor space is needed. In this way the continuous placement of the product increases significantly, while the integrity of the package is maintained and the amount of floor space needed is limited. Although the actual time that the welding jaws are closed around the extreme fins of a package does not change, the applicant's tests have shown an increase in continuous placement of 40% or more. The sealed packages can be pushed onto the exit feed passage rail 30 by any of a number of means, however, in the preferred embodiment after the package has been sealed and the welding jaws have been opened, a package Subsequent entering of the sealing station from the radial advance transit rail 20 will simply push the sealed package from the support platform onto the forward feed transit rail 30. In this way, the support platform of each transport mechanism The seal should align with the forward feed passage rail 30 when the sealing mechanism is in its packet receiving position at the sealing station. This is best shown in Figure 1, wherein the first sealing mechanism 41 is in its receiving position of the package. The package 10D has been pushed from the radial advance transit rail 20 onto the support platform 52. As the package 10D is pushed onto the support platform 52, it pushes the already sealed package 10B over the transit lane. of output advance 30. However, other mechanisms can be used to remove sealed packages. For example, the support platform can be tilted towards the outgoing advance transit lane 30 to allow the sealed package to slide out of the support platforms and over the outgoing advance transit lane 30. The sealed packages removed from the apparatus of sealing of the present invention along the outgoing advance transit lane 30 (10B and 10C of Figure 1) are preferably transferred to subsequent processing steps, such as loading the sealed packages into larger containers for the shipment. The movement of the packages along the outgoing advance transit lane 30 can be achieved by any of a number of well-known conventional means. For example, the forward feed transit rail 30 may comprise a moving conveyor, or the push rods may again be employed to effect movement in the desired direction. The movement of each sealing mechanism or equipment between their respective packet reception and retention positions can be accomplished by any of a number of well-known means. Preferably, an alternating mechanism generally shown as 13 in Figures 1 to 3 can be provided. The first and second sealing mechanisms 41 and 42 are linked to one another in such a way that the movement of one of the sealing mechanisms coincides with the movement of the other. Both sealing mechanisms move simultaneously in the same direction and their respective movement is limited such that each of the sealing mechanisms is able to move only between a position of reception of the package and a position of retention of the package. The receiving position for each sealing mechanism is identical, and is preferably aligned with both the radial advancing transit rail 20 and the forward advancing transit rail 30 at the sealing station. In fact, the radially advancing transit rail 20, the support platform of a sealing mechanism in its receiving position, and the forward advancing transit rail 30, preferably define a flow path for the packages.

In this way, a substantially straight horizontal travel line can be maintained with the packages deviating from this path only when the welding jaws are securely closed around the end flaps of the package. In a preferred embodiment, the alternating mechanism 13 comprises left and right frame members 71 and 171 respectively, which provide a support structure for the two sealing mechanisms. These frame members each have an inner groove 73 and 173 within which they can move the sealing mechanisms. The pulley wheels 74 are provided in each sealing mechanism, and each has a shank 75 or other extension that is positioned within the slots 73 and 173 as shown. The pins 75 ensure that the sealing mechanisms move in the proper line of travel between the frame members. Also the first and second sealing mechanisms 41 and 42 are linked to each other by means of the articulated arm 70. The articulated arm 70 can be of any configuration, and, for example, it can be just a rigid beam secured to both mechanisms of sealed. However, in the embodiment shown the articulated arm 70 comprises a rack which meshes with the pinion 68. The simultaneous movement of the first and second sealing mechanisms 41 and 42 can thus be achieved by providing a means for rotating the pinions 68. Preferably, a servomotor is used to provide uniform, bidirectional movement, however other types of motors may be used for this purpose. Because of the articulation of the first and second sealing mechanisms as well as the use of a rack and pinion system an individual servomotor can drive an individual pinion in order to provide the necessary movement of both sealing mechanisms. Although the embodiment shown in Figures 1 to 3 employs a rack and pinion drive system, alternate means may be employed to simultaneously move the first and second sealing mechanisms 41 and 42. For example, an impeller may be employed. chain, a screw driver or a belt impeller for this purpose, and all are mechanisms well known to those skilled in the art. Regardless of the type of driving mechanism employed, it is preferred that the first and second sealing mechanisms 41 and 42 move in a vertical plane which is substantially perpendicular to the product flow path (i.e., the defined flow path). by the radial advance transit lane 20 and the exit advance transit lane 30). In the preferred embodiment, slots 73 and 173 define the limit of movement, and preferably two support positions are provided. In the configuration shown in Figures 1 and 2, the upper pins 75 in the second sealing mechanism 42 abut the upper surfaces 80 and 181 of the grooves 71 and 171, respectively. The upper surfaces 80 and 180 prevent further upward movement, and in this way provide a superior support position wherein the first sealing mechanism 41 is in its packet receiving position and the second sealing mechanism 42 is in its position of retention of the package. In Figure 3, the lower pins 75 in the first sealing mechanism 41 abut the bottom surfaces 81 and 181 of the slots 71 and 171, respectively. The lower surfaces 81 and 181 prevent further downward movement of any sealing mechanism, and thus provide a lower support position wherein the first sealing mechanism 41 is now in its pack retention position and the second sealing mechanism 42 is now in its receiving position of the package. In this way, the total sealing apparatus comprising the first and second sealing mechanisms 41 and 42 is capable of moving between the upper and lower support positions. When the sealing device is in any support position, one sealing mechanism is in its receiving position of the package in the sealing station and the other is in its position of retaining the package. Furthermore, the movement between the two support positions only occurs after both sets of welding jaws are securely closed around the open end of a package. It should be noted that the period of time in which the sealing apparatus remains in one of the two support positions may vary depending, among other things, on the length of time needed to obtain the proper seal, the length of time between subsequent packages that are transported along the radially advancing transit lane, and the length of time needed for the sealing mechanisms to move from one support position to the other. In fact the time of support or rest, and consequently the time that a sealing mechanism is in its position of retention of the package, can be very short, allowing only enough time for a sealed package to be pushed from a sealing mechanism and replaced by a later package. Although the above preferred embodiments employ two sealing mechanisms, the present invention also includes providing any number of sealing mechanisms. For example, three sealing mechanisms can be employed in a manner similar to that described above, with each sealing mechanism being able to move between a receiving position and or more holding positions. While one of the sealing mechanisms is in its receiving position the two remaining mechanisms can be in a holding position to complete the sealing process. In this way, three support positions would be necessary when using the previously described alternate apparatus. Alternatively, they may be arranged in a rotating "wheel" configuration. Each sealing mechanism would be able to move between a receiving position in the sealing station, and one or more holding positions. In this mode, the number of support positions would again correspond to the number of sealing mechanisms, and each mechanism would progress in one complete revolution before returning to its receiving position. The above description of the preferred embodiments is by no means exhaustive of the variations of the present invention that are possible, and has thus been presented solely for purposes of illustration and description. The modifications and variations obvious to those skilled in the art will be apparent in light of the teachings of the foregoing description. For example, the sealing mechanisms can be configured to move in a horizontal (or lateral) direction instead of vertical. In addition, various other mechanisms can be employed to provide movement to the sealing mechanisms other than the rack and pinion system. The packages can also be sealed by a mechanism other than a pair of welding jaws. Therefore, it is intended that the scope of the present invention be defined by the claims appended thereto.

Claims (10)

1. A method for successively sealing the open ends of a plurality of packages (10A-F) conveyed in series along a radially advancing transit rail (20), wherein the open end must be retained in its sealed condition for a a certain minimum sealing time, characterized by: a) providing a sealing station aligned with the radial advancing transit rail (20) to receive the packages (10A-F) to be sealed; b) transporting a first package (10C) from the radial advance transit lane (20) to the sealing station; c) coupling the open end of the first package (10C) in the sealing station for the sealing operations: d) maintaining the coupling of the first package during the minimum sealing time to seal its open end while transporting a second package ( 10D) from the radial advance transit rail (20) to the sealing station; e) coupling the open end of the second pack (10D) in the sealing station for the sealing operations; f) maintaining the coupling of the second package (10D) during the minimum sealing time to seal its open end while transporting a subsequent package (10E) from the radial advancement transit rail (20) to the sealing station; and g) repeating steps (b) - (f) as desired for subsequent packages to allow sealing of a plurality of packages moving along the radial advance transit rail (20) to be sealed.

2. A method for successively sealing the open ends of a plurality of packages according to claim 1, further characterized by alternatingly moving a first sealing mechanism or equipment (41) between a receiving position aligned with the advancing transit rail radial (20) in the sealing station to receive the packages to be sealed, and a holding position to maintain the coupling of the packages for the sealing operations.

A method for successively sealing the open ends of a plurality of packages according to claim 2, further characterized by the step of reciprocatingly moving a second sealing mechanism (42) between a receiving position aligned with the transit rail of radial advance (20) in the sealing station to receive the packages to be sealed, and a holding position to maintain the coupling of the packages for sealing operations, wherein the first and second sealing mechanisms (41 , 42) are aligned alternately with the radial feed rail (20).

A method for successively sealing the open ends of a plurality of packages according to claim 1, further characterized by the step of releasing the sealed packages from the sealing station, wherein the transportation of a subsequent package (10E) that It is going to be sealed in the sealing station helps to release a sealed package from there.

A method for successively sealing the open ends of a plurality of packages according to claim 3, further characterized in that said first and second sealing mechanisms (41, 42) are linked to each other in such a way that the step of moving one of said mechanisms to its retention position occurs simultaneously with the step of moving the other sealing mechanism to its receiving position.

6. A method for successively sealing the open ends of a plurality of packages according to claim 3, further characterized in that each of said sealing mechanisms (41, 42) comprises a pair of opposed welding jaws (61A-B, 62A- B) capable of moving between the open and closed positions, and wherein the step of coupling the open end of a package comprises closing said jaws (61 AB, 61 AB) around said open end.

An apparatus for successively sealing the open ends of a plurality of packages (10A-F) that are transported in series along a radially advancing transit rail (20), comprising a sealing station aligned with the rail radial feed transit (20), characterized in that: a plurality of sealing mechanisms (41, 42) are provided at the sealing station for coupling the open end of a package and maintaining the coupling; and an alternating mechanism (13) which selectively moves each sealing mechanism (41, 42) between a receiving position aligned with the radial advancement transit rail (20) at the sealing station, and a holding position which is not immediately aligned with the radial advancement transit rail (20) and allows another sealing mechanism to be aligned with the radial advancement transit rail (20).

8. An apparatus according to claim 7, further characterized in that said first and second sealing mechanisms (41, 42) are provided, said sealing mechanisms (41, 42) linked to each other such that one of said stations it is in its hold position when the other station is in its receiving position.

9. An apparatus according to claim 7, further characterized in that each of said first and second sealing mechanisms (41, 42) has a package support (51, 52) for retaining a package thereon, and a mechanism of sealing to seal said package.

10. An apparatus according to claim 8, further characterized in that said first and second sealing mechanisms (41, 42) are connected to each other in such a way that said mechanisms can be moved concurrently from each other, and wherein the retention position of the second sealing mechanism (42) is located above the plane of said radially advancing transit rail (20), and the retention position of said first sealing mechanism (41) is located below the plane of said radial advance transit lane.