Abstract:
A machine for container formation by folding a die-scored paperboard structure to close flaps shaped by the scoring that serve as the top and bottom of the container. A scored paperboard sheet is loaded onto a male pedestal inner pattern such that the foldable top and bottom container portions extend beyond the pattern, whereupon armature driven semicircular outer patterns, having upper and lower fingers adapted to be driven by corresponding fluid driven pin stabilizers, close upon the sheet. While closed over the sheet, the pins are activated to move the fingers inward on the inner pattern and force fold the container along the score lines, followed by automatic retraction of the pins and outer patterns. The container is thus pre-folded in preparation for shipping as a flat paper form that is ready for folding on the crease lines thus formed. One or both flaps of the container can be folded along the crease lines to form a closure at one or both ends. When folded, the flap forms a plurality of inwardly directed pyramidal segments that are crimped along the container axis to form the closure.

Description:
REFERENCE TO PREVIOUSLY FILED APPLICATIONS 
     This application is a C.l.P. of application Ser. No. 08/778,109 filed on Dec. 21, 1996, now U.S. Pat. No. 5,909,842, which in turn is a C.l.P. of application Ser. No. 08/624,074 filed on Mar. 29, 1996, now abandoned. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a machine for folding containers, and more particularly to an improved machine for folding a die-scored box blank along score lines impressed by the die. The invention also relates to a prefolded container blank and an assembled container with one or both ends closed with a fanfold closure. 
     BACKGROUND OF THE INVENTION 
     Advances in technology now enable construction of containers from a broad variety of materials that may be laminated or otherwise coated. A box folding procedure may be followed in succession by a sealing process, dependent on whether the container is intended for storage of dry or liquid contents. 
     The initial activity in box folding is scoring the container blank to form segments or box sections that are divided by weakened points which are the score lines. The prior art folding procedure generally provides for advancing container blanks along a conveyor belt to a backing bar where a folding belt engages a box flap edge to fold the flap onto a container panel. The container blanks are thus folded along their score lines for box formation with the designed segments or sections. 
     The paramount considerations for box folding machines is speed of the operation and minimizing process interruptions, for effective reductions in manufacturing costs. 
     Therefore, a need exists for a paper box folding apparatus that would enable simple manual alignment of the box blank on the backing bar to form properly proportioned segments according to the box design; that would give folds on the score lines to avoid skewing; and, to achieve the folding process with paramount speed and a minimum of interruptions in the process. In addition to the foregoing, a need exists for an inexpensive paper board container that is easy to assemble and close. These are among the objectives that are achieved by the invention disclosed herein. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to pre-form a plurality of prescored fanform flaps for a container closure speedily and with minimal interruptions to permit subsequent completion of the closure manually or by other means. 
     Another object is to prepare a prefolded closure for a cylindrical or frustum-shaped container blank whereby subsequent closure of the container is facilitated. 
     Still another object is a cylindrical or frustum-shaped container having a closure at one or both ends comprising a plurality of fanform pyramidals. 
     These and other objects are accomplished according to the teachings of the present invention by the use of a container folding machine for construction of containers using box blanks having score lines, in preparation for shipping the containers ready for completion of the container formation by manual folding. The machine comprises a male pedestal in a fixed position that serves as an inner pattern adapted to receive a box blank installed on the inner pattern; a press comprising an outer pattern for closure over the inner pattern with a box blank therebetween; and, a means to crease the paperboard along its score lines for formation of a pre-folded container. The pedestal comprises upper and lower edges, and repositioning pedestal fingers pivotally connected along at least one of the edges by pedestal hinges. The hinges are spring loaded to bias the hinges and the fingers between a normal upright position and an inward positions. The press comprises two or more press sides which forms the outer pattern. The press sides include repositioning press fingers that are joined to the press sides by flat hinges and are adapted for inward movement against the inner pattern. Springs interconnect each finger with the press side to which it is hinged to maintain the finger in a normal upright position. An armature controls movement of each press side for closure upon and withdrawal of the press side from the box blank installed on the pedestal. The press includes a hydraulic or pneumatic actuated pin adjacent to a corresponding press finger for engaging the finger to drive the finger inward to contact and to crease the box blank along a score line. Each of the pins is mounted on one or more pin stabilizers surrounding the press and located near the top and/or bottom periphery of each press side. All pins on one stabilizer are connected to a common fluid lead line for simultaneous action thereof. The machine further may include a loading track for positioning a box blank directly adjacent the pedestal and a driver shaft for repositioning a box blank from the loading track for installation on the pedestal. 
     A further embodiment of the present invention is a machine for prefolding one end of a container blank along score lines, said container blank having an interior surface and an exterior surface. The machine contains a plurality of hinged spring-biased pedestal fingers positioned at spaced intervals around a central pedestal and joined thereto by spring-loaded hinges at spaced intervals, and a plurality of press fingers spaced intermediate said pedestal fingers. Means are included to bias each of the press fingers about a flat hinge from their normal position toward the interior of the container blank and to return the pins to their normal position. The pedestal fingers are adapted to be positioned around the interior surface of the container blank and the press fingers adapted to be positioned around the exterior surface of said blank. The fingers on the press and the pedestal are in the shape of a triangle, generally an isosceles triangle and conform in shape to the score lines on the container blank. 
     In yet another embodiment, the present invention comprises a container blank in the shape of a frustum or a cylinder for use as a the container comprising a body having at least one opening at one end thereof. The blank contains a plurality of creases to be folded into fanfold ribs around the opening. The creases are formed by the steps of creating a plurality of score lines around the periphery of the opening to form contiguous triangles; placing the blank in a creasing machine containing a plurality of triangular fingers whereby the fingers are in registry with the contiguous triangles; and actuating the fingers to form creases in the blank along the score lines around the opening. The fingers are composed of a plurality of press fingers spaced apart from one another around the outside of the opening of the container blank, and an equal number of pedestal fingers intermediate the press fingers around the inside of the opening of the blank. The press fingers cause the periphery of the opening to move in on itself, and the pedestal fingers resist the inward movement of the periphery thereby creating the creases. 
     In yet another embodiment of the invention, a container having a closure at one end is composed of a plurality of fanfold ribs round the periphery of the container. The ribs are formed by the steps of a) preparing a container blank in the form of a frustum or a cylinder; b) creating a plurality of score lines around the periphery of the container blank to form contiguous triangles; c) placing the container blank in a creasing machine containing a plurality of triangular hinged fingers whereby the fingers are in registry with the triangles; d) activating the fingers to form creases along the score lines; e) removing the container blank from the machine, and f) folding the periphery of the container blank along the creases to form a plurality of inwardly directed ribs serving as the closure for the container. The container can have a circular or frusto-conical cross section whereupon each of the triangles around the periphery thereof comprises an isosceles triangle having a height equal to the radius of the closure. The fingers are composed of a plurality of press fingers spaced apart from one another around the outside of the container blank, and an equal number of pedestal fingers intermediate the press fingers around the inside of the container blank. 
     In still another embodiment of the present invention, a container is described which is cylindrical or frustoconical in shape. The container has a central axis and peripheral borders at either end defining fold lines. At least one of the two ends is closable with a fanfold closure which comprises a plurality of pyramidal segments, each segment composed of a first set of two isosceles triangles with their bases forming a portion of the end fold line and a second set of two isosceles triangles with their bases forming an axially extending crimp line. All of the triangles have a height equal to the radius of the container at the closure. The bases of the first set of triangles are contiguous to one another along the end fold line, and adjacent triangles form divergent planes as they extend from the base to the axis. Adjacent triangles in the second set diverge from one another as they extend from the container axis to the end fold line, each triangle terminating along the fold line at the intersection between the bases of contiguous triangles in the first set. The two sets of triangles are at right angles to the second set. The pyramidal segments are in non overlapping relationship to one another. Each end fold line is in a single plane, and the peripheral edge of the container blank before forming the closure is in a single plane. 
     Additional features of this invention will become apparent as indicated herein. And further advantages will be apparent to those of ordinary skill in the art upon reading and understanding the following detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevation view in perspective with the box blank descending on the pedestal inner pattern with the press sides ready for closure; 
     FIG. 2 discloses the folding machine with the blank installed on the pedestal; 
     FIG. 3 shows the equipment in operative condition with the press sides closed over the container blank on the pedestal; 
     FIG.  4 . shows the operative state of the equipment when the press is closed and the contact fingers pressured inward; 
     FIG. 5 shows the machinery in operation when the press is closed, the contact fingers pressured inward, and the fingers are fully engaged to form creases to prefold the box; 
     FIG. 6 discloses the equipment having the fingers withdrawn after the box has been pre-folded and prepared for manual closure; 
     FIG. 7 discloses the equipment when the press sides have been withdrawn; 
     FIG. 8 discloses removal of the pre-folded box and readiness of the machinery for installation of another blank on the pedestal; 
     FIG. 9 is an elevation view showing a loading track for box blanks having a flat, pre-sealed bottom; 
     FIG. 10 is an elevation view that shows the progression of box blanks on the loading track for positioning directly adjacent the pedestal; 
     FIG. 11 shows a box blank installed on the pedestal by the bottom driver. 
     FIG. 12 is an elevational view of a press finger; 
     FIG. 13 is an elevation taken at right angles to the view shown in FIG. 12; 
     FIG. 14 is a perspective view of the precreased frusto-conical container blank seen in FIG. 8 with the top flap completely folded inward with a plurality of pyramidal fanfolds crimped to form a closure; 
     FIG. 15 is perspective view of the container blank of FIG. 14 showing a partially closed end; 
     FIG. 16 is a perspective view of the container with both ends completely closed. 
     FIG. 17 is a top view of a box blank for forming a flat bottom container with a reclosable fanfold closure top of the container; 
     FIG. 18 is a perspective view of the folding machine including the forming head press retaining a box blank above the deck with the right forming hand hinged to the deck, the mounting ring with press fingers and retrieval arm below; 
     FIG. 19 is a side view of the folding machine showing the deck with the forming head press in its downward cycle position, the right and left forming hands in open position, the retrieval arm urging the box blank downward for alignment with the press fingers mounted on the ring; 
     FIG. 20 is a side view of the folding machine, the fanfold top of the box blank aligned with the press fingers; 
     FIG. 21 is a side view of the folding machine showing the press fingers creasing the fanfold closure top of the container; 
     FIG. 22 is a side plan showing a compression bar and its drive cylinder, pneumatic piston and drive shaft communicating with a manifold through right and left air valves, the right forming hand with its respective drive cylinder and pneumatic piston and drive shaft, manifold and air valves; 
     FIG. 23 is a side plan showing a press finger with its respective pneumatic drive means. 
     FIG. 24 is a top view of the fanfold container formed by the machine using the box blank of FIG.  17 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     It will be understood by Reference to FIG. 1, that the container folding machine  10  disclosed herein comprises a central pedestal  14  having upper edge  20  and lower edge  24 . A plurality of triangular repositioning pedestal fingers  18  are pivotally joined to, and extend upward from upper edge  20 . Additional repositioning pedestal fingers are pivotally joined to and extend downward from the lower edge  24  of the pedestal. The central pedestal  14  forms an inner pattern which serves as a backing bar or plate for each of the box blanks  100  that is processed for folding. 
     In FIG. 1, a frusto-conical box blank  100 , having score lines  104 , is positioned on the pedestal  14  that is an inner pattern with the press sides  26   a,   26   b  ready for closure. Each of the pedestal fingers  18  is adapted for inward movement in the folding process and return to its upright position by its interconnection with the pedestal  14  with spring loaded hinges  22 , such that each pedestal finger  18  is normally in the upright position. 
     Referring to FIG.  1  and FIG. 2, the press sides  26   a,   26   b,  are correspondingly shaped to fit over the pedestal  14 . The press sides  26   a,   26   b  form an outer pattern that is adapted for closure over the inner pattern to crease the box blank  100 , which is preferably a paperboard material, along its score lines  104  for formation of a pre-folded container  108 . The press sides have a top periphery  30   a,    30   b  and a bottom periphery  38   a,   38   b.    
     It will be understood that while the pedestal  14  shown here is a frustum, the pedestal  14  may have cylindrical, square, rectangular, multi-sided or other forms for construction of similarly shaped boxes with one or more collapsible, reclosable ends. Furthermore, the triangular pedestal fingers  18  shown here, may have other shapes analogous to the top and bottom segments of a particular die-cut box blank  100 . 
     Each of the press sides  26   a,   26   b  is also equipped with projecting, repositioning press fingers  28 , that are each triangular in shape and are adapted for inward movement by interconnection to the top periphery  30   a,   30   b  and the bottom periphery  38   a,   38   b  of each press side  26   a,   26   b,  by means of a flat hinge  32 . When the press sides close around the pedestal, the triangular press fingers and the pedestal fingers are in alternate positions around the peripheral edge of the box blank. 
     Movement of the press sides  26   a,   26   b  is controlled by a respective armature  27   a,   27 b, connected to a central joint or knuckle (not shown), that allows the armatures to move in and out, e.g. by operation of foot pedals (not shown), for closure upon, and withdrawal from, the pedestal  14 . Meanwhile, pedestal  14  is fixed in stable position upon a horizontal deck  40 . 
     The box blank is aligned for conformity of its segments with the pedestal fingers  18 , upon installation on the pedestal as illustrated in FIG. 3, FIG. 4, and FIG.  5 . When the press sides  26   a,   26   b  are closed over the pedestal  14 , with the box blank  100  therebetween, then pins  44  that are mounted on upper and lower pin stabilizers,  46 , 48  of each of the press sides  26   a,   26   b,  and positioned adjacent a corresponding press finger  28  thereof, are simultaneously driven inward. Each pin  44  communicates through its respective lead line  50  to a common line (not shown) that communicates with a fluid container or tank (not shown) holding a fluid medium under pressure. 
     The preferred fluid medium is compressed air to provide the force necessary to drive the pins  44  inward; and, each of the pins  44  is in fluid communication with the others through the common line  52  for simultaneous action of the pins  44  engaging respective press fingers  28 . When the pins  44  have fully engaged fingers  28 , the box creases are formed on designated score lines  104  for consequent pre-folding of each box. 
     Referring now to FIG.  6  and FIG. 7, following their full engagement with the fingers  28 , the pins  44  are withdrawn to facilitate removal of the pre-folded box  108 , that is now prepared for closure on machine made crease lines corresponding to the score lines  104 . 
     As disclosed in FIG.  7  and FIG. 8, the press sides  26   a,   26   b,  are then withdrawn by radial movement of the armatures  27   a,   27   b,  to facilitate removal of prefolded box  108 , in readiness for installation of the succeeding box blank  100  on the pedestal  14 . 
     Reference to FIG. 9, FIG.  10  and FIG. 11, indicates that in an alternative embodiment for the boxes, the box blanks  100   a  designated for installation on the pedestal  14  may have a flat, pre-sealed bottom section  112 . The blanks  100  or l 00   a  proceed on a loading track for positioning directly adjacent the pedestal  14 , whereupon each box blank  100  or  100   a  is installed on the pedestal  14  by the bottom driver  56 . 
     As noted in FIGS. 12 and 13, each of the press fingers is pivotally joined to the press sides by a flat hinge  32 . The hinge is designed to swing through an arc of about 180° from the closed to the fully open position. When open, each of the press fingers  28  typically is coplanar with the sides  26   a,   26   b  of the press. Shown is an external steel spring  34  with one end  34   a  in contact with the finger  28  and the other end  34   b  secured to the press side  26   a  by suitable means such as a spot weld  36 . In operation, each press finger  28  is pivoted about flat hinge  32  from the vertical position in contact with the periphery of the container to a predetermined position (shown in outline) where the periphery is creased. Then, as the fluid pressure against the pin  44  is released, the spring  34  on the side of the press finger  28  opposite the pin urges the finger back to its normal vertical position. 
     Referring now to FIGS. 14-16, a container blank which has been scored, creased and folded according to the teachings of the present invention is shown. The blank  100  comprises a body portion  101 , a closed first end flap  102  and second creased but unfolded end flap  106 . The flaps are creased along fold line  118 , 120  to fold in toward the axial center line of the blank. FIG. 14 shows the first flap  102  closed in on itself. The flap is composed of a plurality of fanfold ribs in the shape of pyramids  116   a  formed by the folding of the flap along the creased score lines  104 . Each rib is composed of a first set of triangles  112   a,    112   b  and a second set of triangles  114   a,    114   b.  All of the triangles are of equal size and all are in the form of isosceles triangles, the height of which is equal to the radius of the closure circle. The first set of triangles are formed with their bases along fold line  118 . Their planes diverge from one another as they extend radially inwardly from the fold line to the center axis of the container. Conversely, the second set of triangles  114   a,   114   b  have their bases along the axis and their planes diverge from one another as they extend radially outwardly from the axis toward the fold line, terminating at the apex between the bases of the adjacent triangles in the first set  112   a,    112   b  along the fold line  118 . 
     In like manner, FIGS. 15 and 16 show the container of FIG. 14 set upon the closed flap  102 . FIG. 15 shows the second flap  106  folded upon itself preparatory to complete closure. All of the first set of triangles  112   a,    112   b  have been folded along the linear fold line  120  extending around the periphery of the container  101 , and extend radially inwardly the center of the container. Their respective planes diverge from one another as they extend from fold line toward the axis. The second set of triangles  114   a,    114   b  connect the first set of triangles with one another. The bases  122  of the second set of triangles converge toward one another to form a crimp line along the axis of the container thereby forming a complete closing of the flap upon itself. When the flap is completely closed as shown in FIG. 16, the second set of triangles is at right angles to the first set. 
     As shown in FIG. 17, the box blank  500  for container formation includes score lines for creasing along those lines, whereby the container product has a flat bottom  502  and a top opening with a fanfold closure  504 . 
     Another embodiment of the invention, shown in FIG. 18, the folding machine  400  of the invention includes a housing  450  with forming head  514  having downward and return cycles that is shown suspended above the deck  540  in a return cycle or upward position. The box blank  500  is stabilized on the forming head. An opening  541  in the deck allows the forming head to pass therethrough in its downward cycle. The forming head  514  and retrieval arm  556  are both equipped with vacuum pressure tubes  550   a,    550   b  communicating with orifices  558  on respective operating surfaces for alternately retaining the box blank in position on the forming head  514  for passage to the retrieval arm  556  following the first step of the container formation. The right side forming hand  526   b  is connected by hinges  532  to the underside of the deck  540  and connected to its respective shaft  544  with a pneumatic driven piston  551  within a cylinder  552  also fixed to the deck. 
     The mounting ring  546  fixed within the housing  450  below the deck  540  sustains the press fingers  528  that are joined to the ring by hinges  522  and shown with each press finger having a connected shaft  544  that extends from a pneumatic cylinder  552  fixed on the ring to the movable finger. As such, each of the press fingers  528  is moved forward and back by action of a piston  551  within the cylinder  552  pushing and pulling the shaft to simultaneously move each of the fingers. The pistons  551  are moved by pneumatic pressure on either side of each piston provided through tubing  580  connected through inlets  555   a,   555   b  to the cylinders. (See FIGS. 22 and 23.) 
     FIG. 19 demonstrates action of the retrieval arm  556  to clasp the box  500  for downward pull toward the ring  546  and alignment with the press fingers  528 . At this point, the box has been formed to the shape of a cut conical section by sealing glue seams  575  along the sides of the box blank  500  by application of the compression bars  527 , (See FIG.  22 ), over each of the glue seams upon compression of the box sides  503   a,   503   b  over the formation head press  514  by the forming hands  526   a,   526   b.    
     The partially formed container proceeds downward by action of the retrieval arm  556  for position within the ring  546  at a level corresponding to the press fingers  528  as shown in FIG.  20 . The fanfold top  504  is then creased along the score lines of the box blank by simultaneous inward or forward action of the press fingers  528  that is indicated in FIG.  21 . The fingers are impelled by the shaft  544  connected to each finger and to a pneumatically driven piston  551  within a cylinder  552  having right and left inlets  555   a,   555   b.  Compressed air is preferable for providing the pneumatic force to each cylinder. As shown in FIG. 23, the air is forced into each cylinder  552  through a manifold  577  for re-direction to right and left air valves  570   a,   570   b.    
     As shown in FIG. 22, operation of the forming hands  526   a,   526   b  to compress sides of the box blank and actuation of the compression bars  527  to seal the glue seams  575  are likewise operated by pneumatic force, preferably air pressure that enters the cylinder through air valves as directed by the manifold  577 . After container formation and folding by the press fingers  528 , the pre-folded container can be automatically or manually removed from the retrieval arm. The containers thus formed remain sufficiently open to be stacked in nested formation. A sequential supply of air pressure to the forming hands and compression bar cylinders, followed by simultaneous supply of compressed air to the press finger cylinders, is achieved using an electro-cam (not shown), that communicates with the manifolds for appropriate, timely air pressure to operate of the machine for manufacture of up to 10,000 containers per hour. The sequential supply of pneumatic and air pressure to each cylinder is synchronized for continuous automatic machine operation without interruption. 
     The folding machine of this invention provides a container that remains closed by an area of stability with a frictional inertia due to contact of the pyramidals, (i.e., upward or downward projecting pyramids formed by successive adjacent triangles), at the fanfold center  501 , as shown in FIG. 24, without a tab or other locking mechanism. 
     Unlike many of the prior art closures, the closures formed according to the present invention can be repeatedly opened and closed with minimal wear. The fold lines and the edges of the container blank are coplanar and linear with no need to form curved, scalloped or sawtooth edges The individual pyramids do not overlap and fold over one another, nor is there any need to twist the container relative to the flap when closing the container. 
     The preceding detailed description should be considered exemplary in nature and not limited to the scope and spirit of the invention as set forth in the appended claims.