Patent Document

BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates generally to apparatus and methods for wrapping articles, and relates more particularly to such apparatus and methods useful for wrapping articles such as candy bars or other food products in a manner incorporating a wrap such as a single or double twist-wrap, an envelope wrap, a bunch wrap or a modified envelope wrap. The invention is applicable to wrapping performed with either a heat sealing method or a cold-seal adhesive.  
           [0003]    2. Related Background Art  
           [0004]    The great majority of candy bars are packaged by being wrapped and sealed in a film of wrapping material, on which is printed the desired package artwork, logos, etc. Such wraps are generally formed in the following way. A continuous film of the wrapping material is printed with the artwork and the like (this is generally done by the vendor of the film, not by the food packager). In the actual packaging process, the products are deposited in the film with proper registration, so that the individual products line up with the artwork on the film. The film is wrapped around the products  12  and sealed in a continuous seam  14  to form a tubular shape  16  (see FIG. 2). This tube  16  is then cut into parts at the correct locations to produce individual tubular lengths of film, each containing one product. Both ends of each of these are then sealed by heat sealing methods or cold-seal adhesive, completing the formation of the familiar wrapped product  20  (see FIG. 1). Commonly, the cutting and the sealing are performed simultaneously, by a mechanism known as a cut-and-seal. These techniques are referred to herein as the conventional “flow-wrap” process.  
           [0005]    Another form of wrap for food products, such as candies, involves wrapping individual pieces of the product in a film that is wrapped around the product, again in a tubular fashion, with a twist in each end (see  30 , in FIG. 3). Small hard candies wrapped in this manner are also a familiar product. (In contrast to this double twist-wrap, various other twist-wrap techniques are used for other products, such as lollipops. Other types of wrapping techniques useful for various food products are the envelope wrap, the bunch wrap and the modified envelope wrap. These wrapping techniques are well understood by those of ordinary skill in the art, and together with the double twist-wrap will be termed “special wraps” or “special wrapping techniques” herein.)  
           [0006]    It would be desirable to provide an apparatus and a method capable of wrapping products, such as candy bars, with a double twist-wrap. It would be especially desirable to provide a modular apparatus that could be used with a standard continuous flow-wrap line of the type used for wrapping candy bars, so that the continuous flow-wrap line could be used as desired either to turn out double twist-wrapped product  30 , or product wrapped in the familiar packaging  20  with both ends of the wrap sealed in a flat shape.  
           [0007]    In addition, it would be desirable to provide a modular apparatus that could be used with a standard continuous flow-wrap line of the type used for wrapping candy bars with one or another of the special wrapping techniques mentioned above, including bunch wrap, single twist wrap, envelope wrap, and modified envelope wrap, such that the continuous flow-wrap line could be used as desired either to turn out product wrapped using such special wrap, or product wrapped in the familiar packaging with both ends of the wrap sealed in a flat shape.  
         SUMMARY OF THE INVENTION  
         [0008]    Accordingly, it is one object of the invention to provide an apparatus that enables one to form such a double twist-wrap packaging for articles reliably and at a high speed.  
           [0009]    It is another object of the invention to provide such an apparatus that can be attached to a flow-wrap line for twist-wrapping (or other special wrapping), and can be deactivated when the line is to be used for standard continuous-flow wrapping.  
           [0010]    It is still another object of the invention to provide a double twist-wrap apparatus having a twist-wrap mechanism that effects the twist-wrap reliably, and which is actuated only when necessary for that purpose, and which is deactivated between the end of formation of one twist-wrap and the beginning of the formation of another twist-wrap by the mechanism.  
           [0011]    According to the present invention, these objects are achieved by providing a modular special-wrap apparatus that has a receiving portion, arranged to receive a partially-wrapped article, for example a tube-wrapped article, into a predetermined location, from another machine, and a special-wrap assembly that forms the desired special wrap. For a double twist-wrap, the special-wrap assembly has rotatable twist grippers to grip the ends of the partially-wrapped article, and to twist the ends to form a twist-wrapped article.  
           [0012]    According to another aspect of the present invention, these objects are achieved by providing a flow-wrap packaging line for wrapping a series of individual articles, which has a first section, in which a film is formed into a tubular wrap about the articles, a cut-and-seal section, in which the tubular wrap is cut between each two successive articles, and a twist-wrap or other special-wrap section, which may be detachable but in any event is capable of being deactivated to permit use of the flow-wrap packaging line without the special wrap. The cut-and-seal section is operable in a first mode, in which the tubular wrap is also sealed, thereby completing wrapping of the articles, and in a second mode, in which the tubular wrap is cut but not sealed. The special-wrap section has a receiving portion, arranged to receive a tube-wrapped article into a predetermined location, from another machine (i.e., the cut-and-seal section), and a portion that forms the desired special wrap. In the case of a twist-wrap, the special-wrap section has rotatable grippers to grip ends of the tube-wrapped article, and to twist the ends to form a twist-wrapped article.  
           [0013]    According to another aspect of the invention, these objects are attained by providing a twist wrap apparatus that has a receiving portion, arranged to receive a tube-wrapped article into a predetermined location, from another machine, and a twist-wrap assembly. The twist-wrap assembly has rotatable twist grippers to grip ends of the tube-wrapped article and to twist the ends to form a twist-wrapped article, and includes a twist-wrap drum and Geneva wheels that drive the twist grippers.  
           [0014]    Other features and advantages of the present invention will be more fully understood from a consideration of the following detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0015]    [0015]FIG. 1 is a view of a product wrapped by a conventional continuous-flow-wrap packaging line like that shown in part in FIG. 4.  
         [0016]    [0016]FIG. 2 shows two articles of a product in a sheet of film wrap that has been folded around the product, and seamed, to form a tubular shape containing the product, prior to the cutting and sealing of the individual packages in conventional flow-wrap processing.  
         [0017]    [0017]FIG. 3 shows a product wrapped using the twist-wrap apparatus of the present invention.  
         [0018]    [0018]FIG. 4 is a schematic view illustrating a twist-wrap apparatus according to the preferred embodiment of the invention, attached to a conventional continuous-flow-wrap packaging line.  
         [0019]    [0019]FIG. 5 is a front view of the modular twist-wrap apparatus according to the preferred embodiment.  
         [0020]    [0020]FIG. 6 illustrates a detail of the second drum of the embodiment shown in FIG. 5, and shows several sets of the twist grippers used to effect a double twist-wrap.  
         [0021]    FIGS.  7 - 10  and  13  illustrate steps in the use of the preferred embodiment to produce a double twist-wrapped product like that shown in FIG. 3. More specifically, FIG. 7 illustrates the transfer of an article to the preferred embodiment from the cut-and-seal device, FIGS.  8 - 10  show the rotation of the articles on the first drum, and FIG. 13 shows the transfer of the twist-wrapped article from the second drum to the third drum of the preferred embodiment.  
         [0022]    [0022]FIG. 11 shows additional details of the construction of the second drum of the preferred embodiment, and in particular shows the Geneva wheels used in that embodiment.  
         [0023]    [0023]FIG. 12 shows one version of a product gripper, as used on all three drums of the preferred embodiment.  
         [0024]    FIGS.  14 A- 14 J are a sequence of views illustrating the operation of the Geneva wheels used in the preferred embodiment. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0025]    [0025]FIG. 4 shows, schematically, the preferred embodiment of the present invention, a modular twist-wrap apparatus  100  together with a conventional continuous flow-wrap packaging line  50  (only a portion of which is shown). The conventional line, being well known, will not be described or illustrated in any detail, and by itself, it does not form part of the present invention (although the combination of the conventional packaging line with the modular apparatus claimed herein, is within the scope of the invention).  
         [0026]    [0026]FIG. 1 illustrates the well-known form of candy bar wrapping  20  obtained with the conventional type of continuous flow-wrapping packaging process. In the conventional process, the products  12  being wrapped are placed on a continuous film of known composition, which is usually preprinted with artwork, logos, product name, etc. The side edges of the film are brought together and welded or glued to produce a seam  14 , thus forming a tubular shape  16  containing the articles  12  being packaged, as illustrated in FIG. 2. In the conventional processing, the tubular shape is then divided into portions each containing one product, and the ends of each portion are welded or glued shut, thus producing the form shown in FIG. 1. These conventional processing steps, like the apparatus used to perform them, are well known in the art and will not be described in greater detail.  
         [0027]    When the modular twist-wrap apparatus  100  of the preferred embodiment is attached to and used with the standard continuous flow-wrap line  50 , the operation of the latter is modified in certain respects. First, since it is desired to form a twist-wrap rather than a flat seam at each end of the package, the placement of adhesive on the film must be adjusted accordingly (the twists that are formed at the ends of the package may be secured in any fashion that proves effective, including the use of either heat-seal or a cold adhesive). Second, the cut-and-seal  55  (the component of the standard continuous flow-wrap line that cuts the tubular shape  16  shown in FIG. 2 into individual portions and then seals the ends), is set only to perform the cutting, and does not seal the ends of the individual packages. Third, the registration and the encoder signals used in the control of the standard line are supplied to the modular twist-wrap apparatus. According to the preferred embodiment, these are the only control signals that need to be supplied to the modular twist-wrap apparatus from the standard line.  
         [0028]    Overview of the Functions of the Modular Twist-Wrap Apparatus  
         [0029]    The modular twist-wrap apparatus  100  receives the tubular products, in their individual “product wraps”  24  (i.e., a segment cut from tube  16  and containing the product  22  to be packaged in a single package), from the upper arbor  57  of the cut-and-seal  55 . Three drums  110 ,  130  and  150  are provided in the twist-wrap apparatus, and perform the following operations on the products.  
         [0030]    The first drum  110  is a transfer-and-rotate drum (see also FIGS. 5 and 9), which receives the product  24  from the cut-and-seal  55  into a product gripper  112  (FIG. 5). While the product  24  is transported to the second drum  130  by rotation of the transfer-and-rotate drum  110 , the product gripper  112  itself is rotated to re-orient the product by 90° (see FIGS. 8 and 9). As a result, the product  24  is delivered to the second drum  130  in an orientation with the open ends of the product&#39;s “wrap” extending in a line parallel to the axis of rotation of the second drum (this is indicated schematically in FIG. 4, where product  24  is viewed from the side while in the cut-and-seal, is rotating on the first drum  110 , and is seen end-on while on drum  130 ).  
         [0031]    The second drum  130  is where the actual twist-wrap formation is performed. For this purpose, the product  24 , held by a product gripper  112  (like those on the transfer-and-rotate drum  110 ), is gripped at each end by twist grippers  132  (see FIG. 6), which are timed to close on the “tube” once the product is securely received by the product gripper  112  on the twist-wrap drum  130 . The twist grippers  132  are then rotated about their own axis (parallel to the axis of drum  130 ) through an angle of 720° while the twist-wrap drum  130  is itself rotating. The force applied in this fashion twists the ends of the “tube” into the desired twist-wrap shape, and the adhesive seals the package. The twist grippers  132  are then opened, and the product  30  (“ 30 ” rather than “ 24 ” because it is now twist-wrapped) is transferred to the third drum  150 , the discharge drum.  
         [0032]    The discharge drum  150  has the function of receiving the packaged product  30  from the twist-wrap drum  130 , delivering the product to the desired discharge point, and discharging it in an orderly fashion.  
       The Transfer-and-Rotate Drum,  
       [0033]    As shown in FIG. 5, the transfer-and-rotate drum  110  has twelve product grippers  112  provided on its circumference. The product gripper  112  comprises a base portion, or head,  114  whose upper surface contains vacuum tooling; that surface is shown as rectangular, but could be given any shape found advantageous in handling the particular product in question. One or more ports  116  (only one is shown) are provided in the upper surface of the head  114  of the product gripper  112  to permit the application of suction from the interior of the drum, to hold the product and the wrap securely against the product gripper  112 . In the preferred embodiment, the product gripper  112  has three linear rods or fingers  118 , two along one side and one on the opposing side of the head  114 . These rods  118  are each movable between a closed position, in which they approach each other and thus grip and secure the product, in cooperation with the vacuum suction, and an open position, in which they are moved outward from each other and away from the product. Additional views of such product gripper  112 ′ and  112 ″ in place on one of the drums, are provided in FIGS. 10 and 12. These versions of the product gripper  112 ′ and  112 ″ differ in a number of details, such as the shape of fingers or rods  118 ′ and  118 ″, from the design shown in FIG. 5.  
         [0034]    The lateral or circumferential surface of the transfer-and-rotate drum  110 , on which the twelve product grippers  112  are mounted, is actually made up of twelve flat surfaces  120  of equal size, each carrying one of the product grippers  112 . Each product gripper  112  is mounted such that it can be rotated on the flat surface  120  on which it is mounted, the rotation being about an axis passing through the product gripper  112  and through the axis of the transfer-and-rotate drum  110  itself.  
         [0035]    As an empty product gripper  112  on the transfer-and-rotate drum  110  passes the upper arbor  55  of the cut-and-seal  50  (see FIGS. 7 and 8), the vacuum suction is actuated in that product gripper  112 , while that holding the product  24  on the cut-and-seal upper arbor  55  is deactivated. This releases the product  24  from the cut-and-seal  50 , and transfers it to the product gripper  112  on the transfer-and-rotate drum  110 . The rods  118  on the product gripper  112  move to their closed position, holding and orienting the product  24  on the product gripper  112 . As the drum  110  rotates about its axis to advance the product  24  toward the twist-wrap drum  130 , the product gripper  112  itself is caused to rotate so as to reorient the product  24  (see FIGS.  8 - 10 ). In the preferred embodiment, the product gripper  112  is rotated through 90°, so that the open ends of the product “tube”  24  lie along a line parallel to the drum axis. This rotation of the product gripper is performed while the drum  110  has rotated through 240°. The product  24  is now in the proper place and orientation to be transferred to the twist-wrap drum  130 .  
         [0036]    The transfer to the twist-wrap drum  130  is performed by the rods  118  of the product gripper  112  being moved to their open position, and then the vacuum suction being deactivated, to release the product  24  onto an identical product gripper  112  on the twist-wrap drum  130 . At the same time, vacuum suction is applied to the product  24  by the product gripper  112  that is receiving the product onto the twist-wrap drum  130 , and the rods  118  of the receiving product gripper  112  are closed to secure the product  24 , completing the transfer. (The remainder of the description of the operation of the twist-wrap drum  130  will be provided in the following section.) As the transfer-and-rotate drum  110  continues to rotate through the next 120°, the product gripper  112 , now empty, is rotated back into its original orientation, so that it is ready to receive a product upon reaching the cut-and-seal  50  again.  
         [0037]    The opening and closing of the rods  118  on the product grippers  112  is controlled by a face cam arrangement, while the rotation of the product grippers  112  to reorient the product is achieved by means of a barrel cam arrangement. Since these techniques are well understood in the art, they need not be described in detail.  
       The Twist-Wrap Drum  
       [0038]    The twist-wrap drum  130 , as is seen most clearly in FIG. 6, actually includes a center drum  134  disposed between an inner drum  136  and an outer drum  138 , all three of which are driven to rotate at the same speed. The center drum  134  has on its lateral or circumferential surface twelve product grippers  112 , which are identical to those of the transfer-and-rotate drum  110  but which cannot rotate about their own axes. As a result, the product remains in the same orientation all the time it is on the twist-wrap drum  130 .  
         [0039]    The inner and outer drums  136  and  138  each carry twelve twist grippers  132 , one adjacent to each of the product grippers  112  on the center drum  134 . Each twist gripper  132  has a pair of jaws  140 , which can open and close, and are supported for rotation about the twist gripper&#39;s own axis (which is parallel to the axis of the twist-wrap drum  130 ). It will be noted that the housings  142  and  144  of the twist grippers  132  are not all the same, some containing one twist gripper  132 , and some containing two each.  
         [0040]    Moreover, posts  146  extend across the center drum  134  and connect these larger housings  144 . The purpose of these double housings  144  and the posts  146  is to supply the drive force from the inner drum  136  to the outer drum  138 , using techniques well-known in the art.  
         [0041]    In the preferred embodiment, the twist grippers  132  do not rotate at all times, but only the amount and at the times necessary to achieve the desired twist-wraps. For this purpose, they are driven by Geneva wheel mechanisms  180  shown in detail in FIGS. 11 and 14A- 14 J. One such mechanism is provided for each of the  24  twist grippers  132 , and is located at one end of the associated twist gripper  132 . In addition, the inner and outer drums  136  and  138  each have a respective disc  182  (see FIG. 14A) on which is mounted a radial gear rack  184 , together with two pins, an acceleration pin  186  and a deceleration pin  188 , which are respectively at the beginning and the end of the radial gear rack  184 . These two discs  182  are stationary during rotation of the twist-wrap drum  130 . Each Geneva wheel mechanism  180  is provided with a mounting  170  that carries the Geneva wheel mechanism  180  smoothly on the surface of the drum  136  or  138 .  
         [0042]    Mounted coaxially with the disc  182  is a rotatable arm  190  for each of the twist grippers  132 , at the radially-outer end of which is a small gear wheel  192 , which in operation rides along and in engagement with the radial gear rack  184 . A cam path  194  is secured to the gear wheel  192 , and is caused to rotate as the gear wheel  192  moves along the radial gear rack  184 . These cam paths each have portions that are to engage the acceleration and deceleration pins  186  and  188 , respectively. During rotation of the twist-wrap drum  130 , each of the cam paths  194  in turn come into engagement with the acceleration pin  186 , and the associated gear wheel  192  then engages and rides along the gear rack  184  to drive the twist gripper  132 , rotating the latter through 720°, thus twisting the end of the product “wrap” and forming the twist-wrap. The formation of the twist-wrap is assisted by an arcuate plate  196  (shown in FIGS. 11 and 13), which helps hold the product in place against the product gripper  112  as the twist grippers  132  twist.  
         [0043]    In operation, when the product gripper  112  on the twist-wrap drum  130  has secured the product  24  from the transfer-and-rotate drum  110 , the twist grippers  132  adjacent to that product gripper  112  are moved to the closed position, gripping the ends of the product “wrap”. After the twist-wrap has been formed, the twist grippers  132  open, and the twist-wrapped product  30  is ready to be transferred to the discharge drum  150 . The opening and closing of the twist grippers  132  is achieved by a barrel cam. The timing of this is controlled by the indexing of the Geneva wheel  180  itself, thus guaranteeing that the twist grippers  132  will engage and securely grip the product “wrap” before the twisting begins. Again, the further-details of these cam arrangements are within the ordinary level of knowledge of those in the art, and need not be described further.  
       The Discharge Drum  
       [0044]    The discharge drum  150  is provided with twelve product grippers  112  identical to those of the other two drums  110  and  130  (but, unlike those of the transfer-and-rotate drum  110 , not themselves mounted for rotation). The transfer of the product  30  from the twist-wrap drum  130  to the discharge drum  150  is achieved in the same manner as that from the transfer-and-rotate drum  110  to the twist-wrap drum  130 , and therefore will not be described in detail.  
         [0045]    The present invention has been described by reference to the preferred embodiment thereof, including enough detail to enable those of ordinary skill to make and practice the invention, and including what the inventors currently consider to be their best mode (if any) of practicing the invention. Nonetheless, many modifications and variations will now be apparent to those skilled in the art, and the scope of the present invention is therefore not to be limited by the details of the foregoing description, but only by the terms of the following claims.

Technology Category: b