Abstract:
A method and apparatus for packaging articles such as flatbreads and stacks of flatbreads utilizes flat loading plates which move axially and rotate about a longitudinal axis. The loading plates have an initial position underneath an input conveyor, and follow movement of an article along the conveyor toward its forward end. As the article moves over the end of the conveyor, it is transferred to the loading plate which then moves the article forwardly to a packaging station, where the loading plate with the article supported thereon is inserted into the open mouth of a container. With the packaged article supported on its upper surface, the loading plate is rotated by about 180 degrees to displace the article and package from the packaging station and to deposit the packaged article onto an exit conveyor. Once the packaged article contacts the exit conveyor, the loading plate is withdrawn from the package and returned to its initial position under the input conveyor. A preferred apparatus comprises two loading plates which alternately receive articles from the input conveyor.

Description:
This application claims the benefit of U.S. provisional application No. 60/100,642 filed Sep. 11, 1998. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a method and apparatus for packaging articles, and specifically relates to a method and apparatus for packaging flat articles such as tortillas and other flatbreads. 
     SUMMARY OF THE INVENTION 
     The present invention provides a method for inserting an article into a package comprising first and second opposed panels and a mouth, the method comprising: 
     (a) moving the article forwardly in a direction parallel to a longitudinal axis on an upper surface of a first conveyor; 
     (b) transferring the article from the end of the first conveyor to the upper surface of a loading plate moving forwardly in a plane below the upper surface of the first conveyor; 
     (c) moving the loading plate having the article on its upper surface into the mouth of the package until the article is completely received inside the package with the first panel overlying the article and the second panel underlying the loading plate; 
     (d) rotating the loading plate with the article and package received thereon about the longitudinal axis until the first panel of the package is received on an upper surface of a second conveyor with the article received on the first panel of the package; and 
     (e) moving the loading plate rearwardly out of the package. 
     In another aspect, the present invention provides an apparatus for inserting an article into a package comprising first and second opposed panels and a mouth, the apparatus comprising: 
     (a) an input conveyor adapted to move the article forwardly in a direction parallel to a longitudinal axis; 
     (b) a packaging station adjacent a forward end of the input conveyor adapted to support the package with its mouth facing the forward end of the conveyor and the first face of the package facing upwardly; 
     (c) a loading plate having an upper surface adapted to support and receive the article from the forward end of the input conveyor; 
     (d) packing means adapted to forwardly move the loading plate with the article on its upper surface to a loaded position in which the loading plate extends into the mouth of the package and the article is received in the package; 
     (e) package inverting means adapted to rotate the loading plate and the associated package and article from the loaded position through an angle of about  180  degrees about the longitudinal axis; 
     (f) exit conveyor means positioned to receive the inverted loading plate and the associated package and article with the first face of the package received on the exit conveyor means and the second face of the package facing upwardly; and 
     (g) withdrawal means adapted to move the loading plate rearwardly in a direction parallel to the longitudinal axis out of the package. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be more fully described, by way of example only, with reference to the accompanying drawings, in which: 
     FIG. 1 is a top perspective view from the front and the right side of a preferred apparatus according to the present invention; 
     FIG. 2 is a partial perspective view from the front and the right side of the apparatus shown in FIG. 1; 
     FIG. 3 is a partial perspective view from the front and the right side of the apparatus shown in FIG. 1; 
     FIG. 4 is a plan view of a preferred bag to be used with the apparatus of FIG. 1; 
     FIG. 5 is a top plan view of the apparatus of FIG. 1; and 
     FIGS. 6 to  13  are partial schematic views of the apparatus of claim  1  used to explain the preferred method of the present invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     A preferred apparatus  10  according to the present invention will now be described with reference to FIGS. 1 to  3 . As shown, apparatus  10  includes an input conveyor  12 , a packaging station  14 , loading plates  16  and  18  and an exit conveyor  20 . The loading plates  16  and  18  receive articles  22  from the input conveyor  12 , move the articles  22  to the packaging station  14  and insert them into packages, and then move the packaged articles  22  to the exit conveyor  20 . 
     Input conveyor  12  transports articles  22 , shown in phantom in FIG. 1, from its rearward end  24  to its forward end  26  in a direction parallel to a longitudinal axis L. For ease of description, the direction in which articles  22  are transported by input conveyor  12  is referred to throughout this application as the forward direction, and is denoted in FIG. 1 by arrow F. 
     The input conveyor  12  has a planar upper surface  28  and a planar lower surface  30 , with conveyor  12  preferably having a low profile such that the distance between the upper and lower surfaces  28  and  30  is small. In a particularly preferred embodiment of the present invention, the distance between the upper and lower surfaces  28  and  30  is about ¾ inches. 
     Articles  22  shown in FIG. 1 preferably each have a flat upper surface  32  and an opposite flat lower surface  34  which is supported on upper surface  28  of input conveyor  12 . The direction in which upper surface  32  faces will be referred to throughout this application as the upward direction. It will be appreciated that the method and apparatus of the present invention can be adapted for packaging a wide variety of articles which, in the most preferred embodiment of the invention, comprises a flatbread, such as a tortilla, or a stack of such flatbreads. Preferably, means (not shown) are provided for arranging the flatbreads into regular stacks and for placing the articles  22  on the forwardly moving surface  28  of input conveyor  12  at evenly spaced intervals. In a particularly preferred embodiment of the invention, the flatbreads have a diameter of about 4 to 14 inches and the stacks have a height of up to about 3½ inches, and the flatbreads are placed on the input conveyor  12  at intervals which depend on various factors such as the rate of forward motion of the conveyor  12 . It will be appreciated that the apparatus and method of the invention can be adapted for use with flatbreads of various sizes and stacks of varying heights. 
     Packaging station  14  is located adjacent the forward end  26  of the input conveyor  12 , and is provided with means for supporting a stack of bags into which articles  22  are inserted. The particular packaging station  14  shown in FIG. 1 comprises a sliding rack  36  which supports two wicket holders  38  and  40 , each of which is adapted to hold a stack of bags (not shown). In FIG. 1, left wicket holder  38  is shown as being positioned directly in front of the forward end  26  of input conveyor  12  to receive articles  22  therefrom. Once the supply of bags in left wicket holder  38  is exhausted, the apparatus  10  is momentarily stopped and the rack  36  is slid to the left so that right wicket holder  40  is in position to receive articles  22  from the forward end  26  of input conveyor  12 . The terms “left” and “right” as used herein refer to the left hand and right hand sides of apparatus  10  as viewed from its forward end. 
     The two wicket holders  38  and  40  are substantially identical to one another and therefore the components comprising wicket holders  38  and  40  are identified by the same reference numerals. Wicket holders  38  and  40  each comprise a tray  42  having side walls  44  and  46  and an end wall  48 , and having a flat bag supporting surface  50  which is height adjustable by means of a spring mechanism or the like (not shown), which is preferably provided underneath bag supporting surface  50 . The bag supporting surface  50  is located in a plane which is positioned below input conveyor  12 . 
     The wicket holders  38  and  40  are especially adapted to support a stack of plastic bags  52  of the type shown in FIG. 4 comprising a rectangular front panel  54  and a rectangular rear panel  56  which are joined to one another along three of their edges to form an enclosure having closed sides  58  and  60 , a closed bottom  62 , and an open mouth  64  along the top peripheral edge  66  of front panel  54 . The rear panel  56  preferably extends above the top peripheral edge  66  of front panel  54  to define a flap  68  which is provided with a plurality of apertures  72  such that a stack of bags  52  can be held in place in tray  42  by metal rods such as pegs or wickets (not shown) extending through the apertures  72 , and can be separated from the stack by being torn from the pegs or wickets in a known manner. Preferably, each bag  52  is stacked with its front panel  54  facing upwardly and with its mouth  64  facing the forward end  26  of input conveyor  12 . 
     The wicket holders  38  and  40  are supported by rack  36  above the exit conveyor  20  having a planar upper surface  74 . The upper surface  74  of exit conveyor  20  preferably moves in a direction perpendicular to the longitudinal axis. The exit conveyor  20  shown in the drawings moves to the right. As shown in FIG. 1, exit conveyor  20  has a front surface  76  to which is attached a horizontal rail  78  along which rack  36  is slidable in a direction perpendicular to the longitudinal axis. The wicket holders  38  and  40  are shown as being supported above exit conveyor  20  and spaced from one another such that the upper surface  74  of exit conveyor  20  extends to the right and left of whichever wicket holder  38  or  40  which is positioned in front of the forward end  26  of input conveyor  12 . This is best illustrated in FIG. 5 which shows portions  76  and  78  of upper surface  74  of exit conveyor  20  being positioned to the left and right, respectively, of left wicket holder  38 . The purpose of having the exit conveyor  20  extend to the right and left of wicket holders  38  and  40  will become apparent from the description of the preferred method of the invention, discussed below. 
     The apparatus  10  also comprises a blower  70  which is mounted close to the forward end  26  of the input conveyor  12 . The blower  70  is provided with nozzles (not shown) which direct jets of air at the stack of bags  52  at the packaging station, thereby causing the mouth  64  of the top bag  52  in the stack to be opened sufficiently to receive an article  22 . 
     The two loading plates  16  and  18  and their associated driving mechanisms are best seen in FIGS. 2 and 3. Preferably, loading plates  16  and  18  and their associated driving mechanisms are mirror images of each other and therefore the corresponding elements of these components are identified by the same reference numerals. The following description relates primarily to left loading plate  16 . Except where otherwise noted, the same description applies to right loading plate  18 . 
     Loading plate  16  comprises a generally rectangular plate member  80  having a rounded front end  82 , two longitudinally extending sides  84  and  86 , and a rear edge  88 . Plate member  80  is preferably made from a thin, rigid sheet material such as metal or rigid plastic, and has a preferred width of about 4 to 14 inches, a preferred length of about 18 to 28 inches, and a particularly preferred thickness of about 0.078 inches. Plate member  80  has planar first and second surfaces  90  and  92  (shown in FIG.  3 ), and is located in a horizontal plane which is intermediate the input conveyor  12  and the bag supporting surface  50  of the wicket holders  38  and  40 . The two longitudinally extending sides  84  and  86  of plate member  80  are separated by a distance which is large enough to support the article  22  and to fit into mouth  64  of bag  52  and be closely received between sides  58  and  60  of bag  52 . The rounded front end  82  of plate member  80  permits easy insertion of loading plate  16  into the open mouth  64  of the bag  52 . 
     The plate member  80  is mounted along its rear edge  88  to the first leg  96  of an L-shaped bracket  94 , the second leg  98  of which is secured to a longitudinal shaft  100  which extends along the longitudinal axis. The two legs  96  and  98  of bracket  94  are perpendicular to each other so that when second leg  98  is oriented vertically, the first leg  96  and the attached plate member  80  are horizontal and parallel to the upper surface  28  of input conveyor  12 . Preferably, as shown in the drawings, the left side  84  of plate member  80  is spaced from the point at which legs  96  and  98  are connected and is therefore somewhat offset from the longitudinal axis for reasons which will become apparent below. 
     The apparatus  10  also includes means for rotating loading plate  16  about the longitudinal axis and for axially moving loading plate  16  relative to the longitudinal axis. As shown in FIG. 3, axial movement is provided by a linear actuator  102  mounted to a side wall  104  of the apparatus  10 . The shaft  100  is mounted parallel to the actuator  102  through a series of supporting plates  106 ,  108  and  110  to a mounting plate  112  which is connected to and is moved longitudinally by the actuator  102 . Rotational movement is provided by a rotational motor  114  mounted to the rearmost supporting plate  110  and connected to shaft  100  through a linear coupling  116 . 
     A method of packaging an article using the apparatus described above is now described below with reference to FIGS. 6 to  13 . As described above, an article  22  is moved forwardly on the upper surface  28  of input conveyor  12  toward the forward end  26  thereof As shown in the schematic top plan view of FIG. 6, as article  22  reaches the forward end  26  of conveyor  12 , loading plate  16  is moved axially forwardly by linear actuator  102  from a rearmost position in which plate  16  completely or substantially completely (as shown in FIG. 6) underlies the input conveyor  12 . Preferably, the rate at which loading plate  16  moves forwardly is substantially the same as the rate at which the articles  22  move forwardly on the input conveyor  12 . 
     FIG. 7 is a schematic side view showing article  22  passing over the forward end  26  of conveyor  12  and being deposited on the first surface  90  of loading plate  16 . Article  22  is preferably a stack of flatbreads  118  which are typically flexible and bend somewhat as they are passed from input conveyor  12  to loading plate  16 . A smooth transfer between conveyor  12  and plate  16  is ensured by providing the input conveyor  12  with a low profile and closely positioning plate  16  under conveyor  12 , so that article  22  experiences only a small vertical drop during the transfer, and by moving the plate  16  at the same rate as the conveyor  12 . FIG. 7 also shows the top bag  52  being held in place atop a stack  120  of bags by a peg  122  passed through aperture  72 . The mouth  64  of bag  52  is maintained in an open position by a jet of air from blower  70  (not shown). 
     In FIG. 8, the stack of flatbreads  118  is now completely supported on the first surface  90  of loading plate  16 . The front end  82  of loading plate  16  is shown as having entered the open mouth  64  of bag  52 , which remains held in place by peg  122 . 
     FIG. 9 shows loading plate  16  in its forwardmost position, at which the front end  82  of loading plate  16  is in engagement with the bottom  62  of bag  52  and has pushed bag  52  forwardly relative to stack  120 , thereby tearing bag  52  from peg  122  at apertures  72  and separating bag  52  from stack  120 . FIG. 10 is a front elevational view of the loading plate  16  at its forwardmost position, also showing L-shaped bracket  94 , shaft  100  and output conveyor  20 . 
     Once the loading plate  16  advances to its forwardmost position as shown in FIGS. 9 and 10, with article  22  completely received in bag  52  which has been separated from stack  120 , the loading plate  16  is rotated by motor  114  in a counterclockwise direction about shaft  100 . FIG. 11 shows loading plate  16  having undergone slightly greater than  90  degrees of counterclockwise rotation from its initial position shown in FIG.  10 . 
     Rotation is continued until loading plate  16  has been rotated by about 180 degrees from its initial position, as shown in FIG.  12 . At this point, the stack of flatbreads  118  is in contact with the upper surface  74  of exit conveyor  20 , and is at least partially supported thereby. Preferably, the first surface  90  of loading plate  16 , now facing downwardly toward conveyor  20 , is spaced from the flatbreads  118 . Since the plate member  80  of loading plate  16  is offset from the longitudinal axis, rotation of loading plate  16  through 180 degrees results not only in inversion of plate member  80 , but also in displacement of plate member  80  to the left of the longitudinal axis. Therefore, the location on conveyor  20  at which the stack of flatbreads  118  is deposited in FIG. 12 corresponds to area  76  shown in FIG.  5 . 
     As shown in FIG. 13, once the stack of flatbreads  118  is deposited on the upper surface  74  of exit conveyor  20 , the linear actuator  102  moves the loading plate axially rearwardly so that it is withdrawn from bag  52 , thereby allowing bag  52  and the enclosed flatbreads  118  to be carried away by the output conveyor  20 . Rearward movement of the loading plate  16  continues until it reaches its rearmost position, at which point it is again rotated in a counterclockwise direction by 180 degrees until it reaches its initial position shown in FIGS. 2 and 3. As best seen in FIG. 3, a cut-out  124  is provided in side wall  104  of apparatus  10  to allow loading plate  16  to be rotated by 180 degrees to its initial position in FIG.  3 . 
     The movement of right loading plate  18  is identical to that described above with respect to left loading plate  16 , except that right loading plate  18  is rotated in a clockwise direction and moves the packaged article  22  from the wicket holder  38  or  40  to area  78  on the upper surface  74  of exit conveyor  20 . Right loading plate  18  is shown in FIGS. 1 and 2 in its inverted configuration with its second surface  92  facing upwardly. It will be appreciated that clockwise rotation of loading plate  18  by 180 degrees from the position shown in FIGS. 1 and 2 will result in loading plate  18  being positioned directly below input conveyor  12  and located at its rearmost position, ready to be moved forwardly and receive an article  22  from input conveyor  12 . Preferably, the movements of loading plates  16  and  18  are synchronized as shown in FIG. 1 so that as loading plate  16  reaches its forwardmost position, loading plate  18  is at its rearmost position and is ready to be rotated to underly input conveyor  12 . 
     Although the invention has been described with reference to certain preferred embodiments, it is to be understood that it is not limited thereto. Rather, the invention includes all embodiments which may fall within the scope of the following claims.