Abstract:
A magazine pressure control is provided with pressure control wheels that are designed to regulate pressure on carton blanks being fed to a folder/gluer in a carton forming operation. These wheels are disposed around the periphery of the carton blank to urge the edges of the cartons forward and to straighten misaligned cartons. A separately controlled motor operates each half of the magazine pressure control. Each motor is controlled by a pressure sensor assembly and regulates the progression of the carton blanks through the magazine pressure control to equalize the pressure around the periphery of the carton blanks as they are presented to the pick face of the folder/gluer.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates to a carton blank feeder that utilizes magazine pressure control to regulate pressure on the pick face of carton forming equipment.  
       BACKGROUND OF THE INVENTION  
       [0002]     Various carton feeding machines have been utilized in the prior art to feed carton blanks in a carton assembly line, such as to a folder/gluer or product packaging machine, to form a blank into a carton. The blanks generally can be fed to the carton folder/gluer manually, by a conveyor, or by chains. Traditionally, the carton stacks are fed manually to the folder/gluer in approximately 2-inch stacks or “slugs.” These stacks can impart unequal pressures on the folder/gluer or on carton blanks aligned for feeding into the folder/gluer. Further, the operating speed of the folder/gluer, although capable of higher rates of speed, generally is limited and governed by the stacks in line for processing, as conventional carton feeding apparatuses typically have been unable to regulate the pressure imparted by the weight and/or alignment of more than a 2-inch stack of carton blanks. Such an uneven pressure distribution of the carton blanks in line for the folder/gluer further does not allow the carton feeding apparatus to recover once an edge of the periphery of the carton blank stack proceeds in a crooked alignment. This resulting imbalance presents blanks to the pick face of the folder/gluer unevenly aligned, causing misfeed to the folder/gluer, destruction of the carton blank, or shut down of the entire system.  
       SUMMARY OF THE INVENTION  
       [0003]     Accordingly, one aspect of the invention is to provide a method and apparatus for feeding carton blanks which addresses the foregoing and other related and unrelated problems in the art.  
         [0004]     The carton blank feeding system of one embodiment of the present invention generally is designed to automate the feeding of carton blanks to replace manual loading of carton stacks and provide safety, ergonomic, and economic benefits. Further, the magazine pressure control provided by the carton feeding system substantially maintains equal pressure and alignment of the carton blanks for presentation to the pick face of a carton feeding apparatus. Control of the carton blank pressure generally is performed by means of feed chains and pressure control wheels positioned within each of the two halves of the pressure control apparatus, with each half being controlled by a separate pressure sensing switch and motor to regulate pressure around the periphery of the carton blanks as they are fed toward the pick face of a folder/gluer. In this regard, segregating into arrangements other than two halves is also within the scope of the present invention.  
         [0005]     Various other objects, features, and advantages of the present invention will become more apparent upon reading the following specification in conjunction with the accompanying drawing figures. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]      FIG. 1  is a diagrammatic front view of an embodiment of the magazine pressure control apparatus of the present invention, taken on the line  1 - 1  of  FIG. 2 .  
         [0007]      FIG. 2  is a diagrammatic side view of an embodiment of the magazine pressure control apparatus, taken on the line  2 - 2  of  FIG. 1 .  
         [0008]      FIG. 3  is a top view of the pressure sensor assemblies of the magazine pressure control apparatus of  FIGS. 1 and 2 .  
         [0009]      FIG. 4  is a front view of the pressure sensor assemblies of  FIG. 3 .  
         [0010]      FIG. 5  is an enlarged view of an embodiment of a pressure control wheel used in the magazine pressure control apparatus. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0011]     The magazine pressure control of the present invention can be used in an assembly line for cartons of the type, for example, which hold cans, bottles or other containers. The carton blanks are fed sequentially to a folder/gluer machine, which forms them into cartons.  
         [0012]     The magazine pressure control apparatus  10  in accordance with one embodiment of the present invention may be positioned to receive the carton blanks just before they reach the pick face of a folder/gluer. A stack of carton blanks B is fed toward the pick face of the folder/gluer (not shown) through the magazine pressure control apparatus  10  by overlapping back and front feed chains. As shown in  FIG. 2 , at the left-hand side of the apparatus back left-hand feed chain  11  passes around left-hand side plate  20 , and overlaps front left-hand feed chain  12 . In a corresponding arrangement on the right-hand side of the apparatus (not shown in  FIG. 2 ), a back right-hand feed chain passes around a right-hand side plate and overlaps a front right-hand feed chain. At the folder/gluer pick face, each lead blank is picked off the stack in turn by an arm  13  having a vacuum cup  14  at its end and transported thereby to the folder/gluer, as is known in the art.  
         [0013]     The magazine pressure control apparatus  10  comprises an outer frame  15  and inner frame  16 . The inner frame  16  is attached to the outer frame by clamps  17  or other means so that it can be moved to permit precise alignment with the folder/gluer and allow for variations in the size and orientation of the folder/gluer. The inner frame  16  has an opening in its center through which the carton blanks B are fed.  
         [0014]     Motors  101 ,  201  are disposed on the right and left sides of the inner frame  16 . As shown in  FIG. 1 , these motors are located at the top of the frame, but they could be positioned at any other convenient location on the frame.  
         [0015]     Describing first the apparatus at the right-hand side of  FIG. 1 , a sprocket  102  is carried on the output shaft of motor  101  and drives sprocket  103  via chain  104 . Sprocket  103  rotates upper horizontal shaft  105 , which in turn rotates vertical shaft  106  via bevel gears  107 . At the bottom of shaft  106 , bevel gears  108  on vertical shaft  106  engage bevel gears on horizontal shaft  109 , which carries a pulley  110  near its outer end. Pulley  110  drives timing belt  111  to cause rotation of pulley  112  and lower horizontal shaft  113  on which pulley  112  is mounted. Mounted on shaft  113  are sprockets  114 ,  115 , which drive the right-hand front feed chain and right-hand back feed chain, respectively. For clarity, the feed chains and side plates are not shown in  FIG. 1 . It will be understood by those skilled in the art that shafts  105 ,  106 ,  109 ,  113  are mounted for rotation on the inner frame  16  by means of suitable bearings, some of which are shown in  FIG. 1  as pillow blocks  116 .  
         [0016]     Mounted on shafts  105 ,  106 ,  109  are a plurality of pressure control wheels  117   a - f.  As shown in  FIG. 5 , each of these wheels comprises a disc  118  which is gear-like in appearance, the circumference of the wheel being provided with teeth of such a size and shape as to engage the edges of the carton blanks and feed them toward the pick face of the folder/gluer without tearing or scuffing them. The pressure control wheels in one preferred embodiment are approximately  3  inches in diameter, although it will be understood that wheels of other diameters can be used depending on the size and shape of the carton blanks which are being fed to the folder/gluer. Each pressure control wheel is attached to the shaft on which it is mounted by setscrews  119  or other suitable means, so that it will rotate with the shaft but can be moved to different positions along it, or removed from the shaft as desired.  
         [0017]     Instead of a disc  118  with a toothed circumference as shown in  FIG. 5 , the pressure control wheels may utilize any other arrangement suitable for engaging and imparting movement to the edges of the carton blanks. For example, the circumference of the disc  118  could be knurled, or a rubber ring or tire could be mounted around the periphery of the disc.  
         [0018]     The left-hand side of the magazine pressure control apparatus shown in  FIG. 1  is similar to the right-hand side. Motor  201  drives upper horizontal shaft  205  via sprockets  202 ,  203 , and chain  204 . Vertical shaft  206  is driven through bevel gears  207  and drives horizontal shaft  209  through bevel gears  208 . Lower horizontal shaft  213  is driven via pulleys  210 ,  212  and timing belt  211 , and carries sprockets  214 ,  215  for driving the left front feed chain and left back feed chain respectively. An intermediate horizontal shaft  218  is driven off vertical shaft  206  by bevel gears  219 . As on the right-hand side of the apparatus, the various shafts  205 ,  206 ,  209 ,  213 ,  218  are mounted for rotation on the frame in suitable bearings, some of which are shown as pillow blocks  216 .  
         [0019]     As shown in  FIG. 2 , left-hand back feed chain  11 , driven by sprocket  215 , follows a path around the periphery of left-hand side plate  20 . Sprocket  214  drives sprocket  230 , mounted on a shaft at the front of frame  16 , via chain  231 . A sprocket mounted on the same shaft as sprocket  230 , and behind sprocket  230  in  FIG. 2 , engages the left-hand front feed chain  12  and drives it in the path shown in  FIG. 2 . It can be seen from  FIG. 2  that the paths of the front and back feed chains overlap in the vicinity of the opening through frame  16 . The right-hand back and front feed chains are similarly driven in corresponding paths by sprockets  114 ,  115  at the right-hand side of the frame  16  ( FIG. 1 ).  
         [0020]     The sizes of the sprockets  114 ,  115 ,  214 ,  215  are preferably chosen so that the back feed chains will run slightly faster than the front feed chains, in order to pull the bottoms of the carton blanks together. This allows any gap remaining between succeeding stacks of blanks to be taken up. The speed of the front feed chains is generally designed to be the same as the circumferential speed of the pressure control wheels  117 ,  217 .  
         [0021]     It will thus be seen that activation of right-hand motor  101  causes rotation of the shafts  105 ,  106 ,  109  and  113  on the right-hand side of the magazine pressure control apparatus, together with the pressure control wheels  117   a - f  mounted on the shafts and the right-hand feed chains. Likewise, activation of left-hand motor  201  causes rotation of the shafts  205 ,  206 ,  209 ,  213  and  218  on the left-hand side of the magazine pressure control, together with the pressure control wheels  217   a - f  mounted thereon and the left-hand feed chains  11 ,  12 .  
         [0022]     Pressure control wheels  217   a - f  are of the same construction as pressure control wheels  117   a - f.    
         [0023]     As shown in  FIGS. 2, 3  and  4 , the magazine pressure control apparatus further comprises right-hand and left-hand pressure sensor assemblies  120 ,  220  (only left-hand assembly  220  is shown in  FIG. 2 ), which are located at the pick face of the folder/gluer, where they will be contacted by the carton blanks B which are being fed toward the pick face by the feed chains  11 ,  12  and pressure control wheels  117 ,  217 .  
         [0024]     Assemblies  120 ,  220  are mounted on fixed plate  121  attached to the frame  16 . Considering first the left-hand assembly  220 , a movable plate  222  is slidably mounted relative to fixed plate  121  by means of a rail  223  attached to the bottom of plate  222  which slides in a suitable slide bearing  224 . Movable plate  222  is biased away from the pick face by compression spring  225 , which acts between a block  226  fixed to the bottom of movable plate  222  and block  127 , attached to the upper surface of fixed plate  121 . At the edge of the movable plate  222  which is remote from the pick face is fastened an upstanding roller mount  228 , provided with horizontal bores  229 . Received in bores  229 , and releasably fastened therein by setscrews  230 , are shafts on which are mounted one or more rollers  131 . The rollers are rotatable on the shafts, and are held thereon by clamp collars  132 . A plate  233  connected to the bottom of fixed plate  121  carries a proximity switch  234  in position to be engaged by movable plate  222 . The switch  234  is connected via suitable circuitry to the left-hand motor  201 , such that the motor  201  is actuated when the movable plate  222  is out of engagement with the switch  234 , but the power to the motor  201  is cut off when the movable plate moves back against the force of spring  225  to contact the switch  234 .  
         [0025]     It will be seen from  FIG. 3  that the right-hand pressure sensor assembly  120  is aligned transversely of the feed direction with the left-hand assembly  220  and is substantially a mirror image of the left-hand assembly, having a movable plate  122 , rail  123 , bearing  124 , compression spring  125 , block  126 , roller mount  128  with bores  129  and setscrews  130 , plate  133  and proximity switch  134 , which is connected by suitable circuitry to right-hand motor  101 .  
         [0026]     As shown in  FIGS. 3 and 4 , the shafts in bores  129 ,  229  may be of different lengths, and may be fixed in different positions relative to the roller mounts  128 ,  228 . This allows the use of different numbers and/or sizes of rollers  131  in various positions on the roller mounts  128 ,  228 , depending upon the configuration of the carton blanks being fed. For example, in the particular arrangement shown in  FIGS. 3 and 4 , the uppermost shaft in left-hand roller mount  228  is longer than the other shafts in that mount, so that two rollers may be mounted on it. This allows the upper left-hand rollers to contact the blank B across substantially all of its lower left-hand side (see  FIG. 1 ). In the right-hand roller mount  128 , the shafts are fixed in the bores  129  so that they protrude on both sides of the mount. This allows short rollers  131   a  to be mounted on the left-hand ends of the shafts, and rollers  131  to be mounted on the right-hand shaft ends, thereby likewise providing more complete contact with the carton blank. Many other roller arrangements are possible, simply by substituting shafts of different lengths and/or rollers of different sizes.  
         [0027]     In operation, motors  101 ,  201  are energized to actuate the left- and right-hand feed chains and rotate the pressure control wheels  117   a - f  and  217   a - f.  The feed chains feed successive stacks of carton blanks B toward the pick face of the folder/gluer. As shown in  FIG. 2 , the feed direction may be inclined at an angle to the horizontal, typically about 10°. As the carton blanks enter the magazine pressure control  10 , their edges are engaged by right-hand and left-hand pressure control wheels  117   a - f  and  217   a - f.  The pressure control wheels are positioned on shafts  105 ,  106 ,  109  and  205 ,  206 ,  209  so that they will engage the top, bottom and side edges of the carton blanks. For example, as can be seen in  FIG. 1 , pressure control wheels  117   b - e  are positioned on right-hand shaft  106  in spaced locations to engage the protruding parts on the right-hand edge of blank B, while pressure control wheels  217   a - d  are positioned on shaft  206  in two groups of two, to engage the two protruding parts on the left-hand edge of blank B. Pressure control wheel  117   a  engages the top edge of the blank, and pressure control wheels  117   f,    217   e,    217   f  engage the bottom edges of the blank. It will be understood that since the pressure control wheels are attached to the shafts by setscrews  119  or other suitable means they may be moved to different positions on the shafts; also, they can be added to or removed from the shafts. This allows the pressure control wheels to be repositioned on the shafts, if necessary, in order to engage the edges of blanks of other shapes. While the pressure control wheels are shown in  FIG. 1  as engaging portions of the top, bottom and both side edges of the carton blanks, a lesser degree of engagement with the periphery of the blanks may be used in some situations.  
         [0028]     As the stack of blanks proceeds through the magazine pressure control apparatus  10 , the engagement of the rotating pressure control wheels  117 ,  217  with the edges of the moving carton blanks around their peripheries feeds the blanks forward while at the same time tending to maintain the blanks in alignment and prevent the blanks from bending, so that they will be presented squarely to the pick face of the folder/gluer.  
         [0029]     When the lead carton blank contacts the rollers  131  on the pressure sensor assemblies  120 ,  220 , it will push the movable plates  122 ,  222  back against the force of springs  125 ,  225 . When the pressure exerted by the lead blank reaches a predetermined value which is great enough to push each of the movable plates  122 ,  222  so far back that they contact switches  134 ,  234 , the power to motors  101 ,  201  is cut off, stopping the feed chains  11 ,  12  and pressure control wheels  117 ,  217 .  
         [0030]     If the carton blanks are square to the pick face of the folder/gluer the predetermined value of pressure will be exerted equally on the left- and right-hand rollers  131 , so that both motors  101 ,  201  will cut off at the same time, discontinuing all feeding. However, if the lead blank is cocked, so that it is not perpendicular to the feed direction, the motors  101 ,  201  may not cut off together. For example, considering  FIG. 3 , if the lead blank is cocked so that its right-hand side exerts more pressure on the right-hand rollers than its left-hand side exerts on the left-hand rollers, the pressure on the right-hand movable plate  122  may reach the predetermined value which is great enough to push the plate  122  back and contact switch  134  to cut off right-hand motor  101  while left-hand motor  201  is still running. When right-hand motor  101  cuts off, the right-hand feed chains  11 ,  12  and pressure control wheels  117  discontinue feeding the right-hand sides of the blanks forward, but the left-hand feed chains  11 ,  12  and pressure control wheels  217  will continue to move the left-hand sides of the carton blanks toward the pick face until the pressure on the left-hand movable plate  222  reaches the predetermined value which is great enough to push the plate  222  back far enough to contact the left-hand switch  234  and stop motor  201 , discontinuing the feeding of the left-hand sides of the carton blanks. At that point, the pressure on both sides of the blanks will have been equalized, and the blanks will be square to the pick face, so that each lead blank in turn can be readily picked off the stack of blanks by arm  13 .  
         [0031]     Thus it will be seen that while the magazine pressure control apparatus of the invention feeds the carton blanks toward the pick face of the folder/gluer, it also can differentially feed one side or the other of the blanks in order to equalize the pressure on them and square them to the pick face, which is perpendicular to the feed direction.  
         [0032]     As the lead blanks are picked off the front of the stack of blanks, the pressure against rollers  131  gradually decreases until, after a few blanks have been picked off, the pressure decreases to such an extent that the movable blocks  122 ,  222  will move away from the pick face under the influence of springs  125 ,  225  until they break contact with switches  134 ,  234 . This will activate motors  101 ,  201  to feed more blanks toward the pick face, once more pushing the movable plates  122 ,  222  back toward the pick face, repeating the cycle of deactivation and activation of the motors  101 ,  201  described above.  
         [0033]     As stacks of carton blanks continue to be fed into the apparatus and blanks continue to be picked off by arm  13 , the motors  101 ,  201  cycle on and off as necessary to maintain the supply of blanks at the pick face under the desired predetermined pressure. The cycling of the motors may also involve one motor operating while the other does not, as described above, in order to differentially feed one side or the other of the blanks toward the pick face as may be necessary in order to keep them perpendicular to the feed direction and square to the pick face.  
         [0034]     The present carton blank feeding system can maintain a large enough stack of carton blanks to enable operation of packaging and/or folder/gluer machinery downstream of the feeding system at higher rates of speed than conventional carton blank feeders. The present carton feeding system is adapted to receive a succession of stacks of carton blanks which are up to at least approximately 12-18 inches thick, thus enabling significantly faster operation of the folder/gluer or other packaging equipment with an uninterrupted supply of carton blanks.  
         [0035]     While a preferred embodiment of the invention has been described above, it is recognized that variations may be made with respect to features and components of the invention. Therefore, while the invention has been disclosed in preferred form only, it will be obvious to those skilled in the art that many additions, deletions, and modifications can be made therein without departing from the spirit and scope of this invention, and that no undue limits should be imposed thereon except as set forth in the following claims.