Abstract:
A conveyor system comprises pairs of vertically spaced and horizontally oriented pulleys and belts that are positioned on opposite sides of a conveyor path. The belts wrap around the pulleys and engage with opposite sides of an object being conveyed by the conveyor, for example an empty plastic blow molded bottle, and convey the object along the conveyor path between the belts. A vertical adjustment mechanism quickly adjusts the vertical positioning of the pairs of pulleys and belts on each side of the conveyor path to quickly adapt the conveyor for conveying different sized objects.

Description:
BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     The present invention pertains to a conveyor system comprising pairs of vertically spaced and horizontally oriented pulleys and belts that are positioned on opposite sides of a conveyor path. The belts wrap around the pulleys and engage with opposite sides of an object being conveyed by the conveyor, for example an empty plastic blow molded bottle, and convey the object along the conveyor path between the belts. More specifically, the present invention pertains to an apparatus that quickly adjusts the vertical positioning of the pairs of pulleys and belts on each side of the conveyor path to quickly adapt the conveyor for conveying different sized objects. 
     (2) Description of the Related Art 
     One type of horizontal belt conveyor that conveys objects in upright orientations between opposed, laterally spaced belts of the conveyor is disclosed in U.S. Pat. No. 5,896,977 which issued on Apr. 27, 1999, and is assigned to the assignee of the present invention and is incorporated herein by reference. This type of belt conveyor is basically comprised of pairs of vertically oriented upstream and downstream shafts where the upstream shafts are laterally spaced on opposite sides of the conveyor path and the downstream shafts are laterally spaced on opposite sides of the conveyor path. Each shaft has an upper and lower pulley mounted to the shaft. The pulleys are typically secured against rotation relative to the shafts by keyways formed in the shafts and keys inserted between the pulleys and shafts. In addition, the pulleys are secured against axial movement on the shafts by set screws on the pulleys or other equivalent mechanisms typically employed in securing a pulley to a shaft. Belts are wrapped around the upper pulleys and around the lower pulleys of the upstream and downstream shafts on each side of the conveyor path. One of the shafts on each side of the conveyor path, either the upstream shaft or the downstream shaft, is rotated by a motive source and rotates the other shaft through the driving engagement of the belts wrapped around the upper and lower pulleys of the two shafts. The shafts are all driven at the same speeds and the pairs of shafts on opposite sides of the conveyor path are driven in opposite directions so that the portions of the belts that mutually oppose each other on opposite sides of the conveyor path travel at the same speed in the downstream direction. 
     The lateral spacing between the pulleys and their belts and the vertical spacing between the pulleys and their belts is determined by the size of the object being conveyed by the conveyor. For example, in conveying empty plastic blow molded bottles, the shape of the bottle determines the positioning of the pulleys on their shafts. Plastic bottles of this type are used as containers for carbonated beverages and other types of beverages. The bottles usually have an upper throat opening that is threaded on its exterior for receiving a cap. As the bottle extends downwardly from the throat, it tapers outwardly along a neck to an annular shoulder defining the upper portion of the main receptacle or body of the bottle. However, the circumference or diameter of the main receptacle or body of the bottle does not always remain constant as the bottle extends downwardly from its shoulder to the bottom of the bottle. More frequently, producers of beverages contained in plastic bottles have designed their own bottle configurations to assist consumers in identifying their products and distinguishing the products of others. For example, the main body of a bottle may begin with a flat exterior circumferential surface just below the bottle shoulder and then may curve inwardly and outwardly as the body extends downward to the bottom of the bottle. The bottom of the bottle also typically has a flat exterior circumferential surface around the bottom that is generally dimensioned at the same size as the circumferential surface of the body just below the shoulder to give the bottle upright stability. 
     In conveyor systems of the type described above, the efficiency of the conveyor system is dependent on the speed in which it conveys objects through the conveyor system. In horizontal belt conveyors of the type described above, when the conveyor system is switched from conveying one bottle configuration to another bottle configuration it is often necessary to reposition the pulleys on their shafts so that the belts wrapped between the upper and lower pulleys of the upstream and downstream shafts will engage against portions of the bottle body that will hold the bottles securely between the belts in their upright orientations as they are conveyed down the conveyor path. In order to reposition the pulleys and their belts vertically on the shafts, the conveyor system must be shut down. The period of time that the conveyor system is shut down while vertical repositioning of the pulleys and belts is taking place significantly detracts from the time efficiency of the overall conveyor system. What is needed to overcome this disadvantage in horizontal belt conveyor systems is a method of quickly adjusting the vertical positions between the pulleys and their belts on the upstream and downstream shafts to decrease the down time of the conveyor system and improve its overall time efficiency. 
     SUMMARY OF THE INVENTION 
     The present invention overcomes the disadvantages of prior art horizontal belt conveyors by providing a horizontal belt conveyor in which the pulleys mounted on each of the vertically oriented shafts can be quickly adjusted vertically relative to each other 
     Each pair of vertically oriented upstream and downstream shafts and the pulleys and belts mounted thereon are supported on a base that can be laterally adjusted toward and away from the conveyor path. Each of the vertically oriented shafts has an upper pulley and a lower pulley mounted on the shaft. The pulleys are keyed to the shafts so that they will rotate with the shafts, however they are free to slide vertically along the lengths of the shafts. 
     The upper pulleys on the upstream and downstream shafts on each side of the conveyor path are sandwiched between a pair of plates that also move upwardly and downwardly over the shafts. In a like manner, the lower pulleys on the upstream and downstream shafts on each side of the conveyor plate are sandwiched between a pair of horizontal plates. Additional tensioning rollers are mounted between each pair of plates. The belts wrapped around the upper and lower pulleys on the upstream and downstream shafts on each side of the conveyor path are also positioned between the pairs of horizontal plates. By adjusting the vertical positions of the plates along the upstream and downstream shafts, the positions of the pulleys sandwiched between the plates are also vertically adjusted on the upstream and downstream shafts. 
     A vertical adjustment mechanism is mounted on the base of the conveyor and is operatively connected with each pair of horizontal plates that sandwich the upper and lower pulleys on each side of the conveyor path. The vertical adjustment mechanism includes a pair of vertically oriented racks that extend upwardly from the base and pass through each pair of plates. The vertical adjustment mechanism also includes a horizontal shaft mounted between each pair of horizontal plates and a pair of pinion gears mounted on the shaft. Each pinion gear meshes with one of the vertically oriented racks. One end of the shaft projects out from between the pair of horizontal plates and a hex head is secured to the end of the shaft. A ratchet wrench is provided that is specifically designed to mate with each of the hex heads on the shafts. Turning the hex head with the ratchet wrench causes the shaft and its attached pair of gears to turn. Turning the gears in this manner causes them to walk either vertically upwardly or downwardly along the vertically oriented racks depending on the direction of rotation of the shaft. This in turn causes the pairs of horizontal plates with the pulleys sandwiched between them to move vertically upwardly and downwardly along the vertically oriented shafts, thereby adjusting the vertical positions of the upper and lower pulleys and their belts relative to each other on each side of the conveyor path. 
     The conveyor is also provided with a vertically oriented scale adjacent upper and lower pulleys on each side of the conveyor path that provides a visual indication of the vertical positioning of the upper and lower pulleys. The vertical scale is mounted to the base of the conveyor by a pivoting connection that enables the scale to be pivoted away from the upper and lower pulleys to replace belts on the pulleys. 
     The horizontal belt and pulley conveyor discussed above enables the vertical positioning of the pulleys and their belts on upstream and downstream shafts to be easily and quickly adjusted, thus reducing the down time of the conveyor and improving its time efficiency. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     Further features of the invention are revealed in the following detailed description of the preferred embodiment of the invention and in the drawing figures wherein: 
     FIG. 1 is an end elevation view of two of the horizontal belt conveyors of the invention positioned opposite each other on opposite sides of a conveyor path; 
     FIG. 2 is a side elevation view of one of the horizontal belt conveyors of FIG. 1; 
     FIG. 3 is an enlarged, side elevation view of the horizontal belt conveyor of FIG. 2; 
     FIG. 4 is a top plan view of one of the horizontal belt conveyors; 
     FIG. 5 is a plan view between the plates that sandwich the pulleys and belts of the conveyor with the top plate removed for clarity; 
     FIG. 6 is a sectioned, end elevation view of one of the pulleys sandwiched between a pair of plates; 
     FIG. 7 is sectioned, end elevation view of one of the racks and its vertical adjustment mechanism; and 
     FIG. 8 is an end elevation view of the scale of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The horizontal belt and pulley conveyor of the invention is an improvement over prior art horizontal belt and pulley conveyors of the type disclosed in U.S. Pat. No. 5,896,977, which issued Apr. 27, 1999 and is assigned to the assignee of the present invention and is incorporated herein by reference. FIG. 1 shows an end view of the conveyor that is basically constructed of a first belt and pulley system  10  and a second belt and pulley system  12  that are mirror images of each other and are positioned opposite each other on opposite sides of a conveyor path  14 . Like the prior art conveyor of the above referenced patent, the two belt and pulley systems  10 ,  12  are each mounted on a table half. The table includes table tops  16 ,  18  that are mounted by slide bushings  20 ,  22  on laterally extending guide rods  24  supported on the frame  26  of the conveyor. The table tops  16 ,  18  and the conveyors  10 ,  12  slide over the guide rods  24  and are laterally adjusted toward and away from each other by manually turning a lateral spacing adjustment mechanism  28  in opposite directions. This adjusts the lateral width of the conveyor path  14  between the two conveyor systems  10 ,  12  to accommodate objects, such as empty blow molded plastic bottles, having different width dimensions. Because both of the belt and pulley conveyor systems  10 ,  12  of the invention are the same, only one will be described in detail. 
     Referring to FIG. 2, the conveyor is supported on a base  32  that is secured to one of the laterally adjustable table tops  16 . The base  32  is a block of metal that has been machined to receive the component parts of the conveyor to be described. As shown in FIGS. 2 and 3, the base  32  is machined with two shaft holes  34 ,  36 . Each shaft hole has a pair of bearings  38  inserted at its opposite ends. The bearings  38  mount an upstream vertical shaft  40  and a downstream vertical shaft  42  to the base for rotation of the shafts relative to the base. The shafts  40 ,  42  are mounted to the bearings  38  to prevent any vertical movement of the shafts relative to the bearings and to the base  32 . One of the shafts, the downstream shaft  42  shown in the drawing figures, projects below the base  32  and has a shaft pulley  44  secured thereto. 
     The table top  16  also supports a motor  46  and a clutch/brake mechanism  48  of the motor. A drive shaft projects from the clutch/brake mechanism  48  below the table top  16  and has a drive pulley  50  affixed thereto. A drive belt  52  is wrapped around the drive pulley  50  and the shaft pulley  44  and on selective operation of the clutch/brake mechanism  48 , the motor  46  rotates the downstream shaft  42  through the drive pulley  50 . 
     The base  32  also supports a pair of vertical racks  54 . The racks  54  are cylindrical metal rods that have horizontal gear teeth  56  cut across one side of the rack. The racks  54  are inserted into vertical holes  58  in the base and are secured in place by pairs of set screws  60  as shown in FIG.  7 . A pair of grooves  62  are cut into the side of the base  32  to accommodate a vertical adjustment mechanism of the racks. The vertical adjustment mechanism includes a bolt  64  that extends through a hole in a flange  66  between the two slots  62  and is screw threaded into the bottom of the rack  54 . A nut  68  is positioned on the bolt  64  and turning the nut to tighten it on the bolt locks the bolt in place. Loosening the nut and turning the bolt in opposite directions provides a fine vertical adjustment of the position of the rack  54  relative to the base  32 . With the rack in its adjusted position the set screws  60  are tightened down to hold the rack in its adjusted position. The racks  54  are parts of a vertical adjustment mechanism that adjusts the positions of pulleys on the shafts  40 ,  42  as will be described. 
     An upper pulley  70  and the lower pulley  72  are mounted on the upstream vertical shaft  40  and an upper pulley  74  and the lower pulley  76  are mounted on the downstream vertical shaft  42 . Each of the pulleys are shown as double pulleys, however single pulleys could also be employed. The upper pulley  70  on the upstream shaft  40  and the upper pulley  74  on the downstream shaft  42  are mounted between a pair of upper plates  80 ,  82 . In a like manner, the lower pulley  72  on the upstream shaft  40  and the lower pulley  76  on the downstream shaft  42  are mounted between a pair of lower plates  84 ,  86 . The upper plates  80 ,  82  and the lower plates  84 ,  86  are also mounted on the shafts  40 ,  42 . The pairs of upper plates and the pairs of lower plates each support portions of the vertical adjustment mechanisms that adjust the vertical positions of the upper pulleys  70 ,  74  on the shafts  40 ,  42  and adjust the vertical positions of the lower pulleys  72 ,  76  on the shafts  40 ,  42 . Because the vertical adjustment mechanisms supported by each pair of upper plates and lower plates are the same, only the vertical adjustment mechanism supported by the pair of upper plates  80 ,  82  positioned on opposite sides of the two upper pulleys  70 ,  74  will be described in detail. 
     FIG. 6 shows the manner in which the upper pulleys  70 ,  74  and the upper plates  80 ,  82  are mounted on the upstream shaft  40  and downstream shaft  42  for vertical sliding movement along the shafts. The shaft  40  has a keyway  88  formed in one side of the shaft. The pulley  70  is secured for rotation to the shaft  40  by a key  90  inserted in the keyway  88 . The key  90  secures the pulley  70  to the shaft  40  for rotation of the pulley with the shaft, but permits the pulley  70  to slide axially along the length of the shaft  40 . The upper plates  80 ,  82  have circular recesses formed in their mutually opposing surfaces and arbor shims  92  or hardened washers are received in the circular recesses. As shown in FIG. 6, the arbor shims  92  engage with opposite ends of the key  90  to move the key with the pulley. Annular thrust bearings  94  with hardened race washers positioned above and below the thrust bearing rollers are positioned between the arbor shims  92  and the opposite top and bottom surfaces of the pulley  70 . Thus, the pulley  70  is free to rotate with the shaft  40  between the upper plates  80 ,  82  and will move axially along the shaft  40  as the upper plates  80 ,  82  are moved together upwardly and downwardly relative to the shaft. 
     As shown in FIG. 5, in addition to the upper pulleys  70 ,  74  sandwiched between the upper plates  80 ,  82 , a plurality of rollers  95 ,  96 ,  97  and an intermediate pulley  98  are also sandwiched between the plates. The two smaller rollers  95  near the pulleys  70 ,  74  are mounted on metal shafts  99 . The four medium rollers  96  near the conveyor path  14  and the two largest rollers  97  near the pulleys are mounted on metal shafts  100  having enlarged circular flanges  101  at their bottom ends. Each of the rollers  95 ,  96 ,  97  are secured for rotation between the upper plates  80 ,  82  by bolts  102  that pass through the top upper plate  80  and the roller shafts  99  and roller shafts  100  and are screw threaded into the bottom upper plate  82 . The rollers are mounted for rotation on the shafts  99  and shafts  100 . Thus, the bolts  102  and the roller shafts  99  and shafts  100  function to maintain the upper plates  80 ,  82  in their vertically spaced relationship. The intermediate pulley  98  is also mounted on a shaft  103  secured between the upper plates  80 ,  82  by a bolt  102 . As shown in FIG. 5, the belt  104  is stretched around the two upper pulleys  70 ,  74  at opposite ends of the plates  80 ,  82  and also around the rollers  95 ,  96 ,  97  and the intermediate pulley  98 . A majority of the rollers  95 ,  96  function to maintain the portion of the belt  104  in the conveyor path  14  where it will continuously engage with objects conveyed through the conveyor path. In addition, the intermediate pulley  98  prevents the belt  104  from sagging horizontally intermediate the two upper pulleys  70 ,  74 . 
     The upper plates  80 ,  82  also support a portion of the vertical adjustment mechanism that operates with the vertical racks  54  to adjustably move the plates  80 ,  82  upwardly and downwardly along the upstream and downstream shafts  40 ,  42  and thereby adjustably positions the upper pulleys  70 ,  74  along the upstream and downstream shafts  40 ,  42 . As shown in FIG. 5, both the upper plates  80 ,  82  have holes  108  that receive the vertical racks  54  therethrough. Notches  110  are cut into the bottom upper plate  82  and intersect with portions of the rack holes  108 , whereby the rack teeth  56  of the vertical racks  54  project into the notches  110 . A groove  112  is cut into the top surface of the bottom upper plate  82  extending from its right end, intersecting the notches  110  and ending just short of the left end of the bottom upper plate  82  as shown in FIG. 5. A horizontal shaft  114  is laid in the groove  112  and is held in the groove by portions of the circular shaft flanges  101  of the two largest rollers  97  adjacent the upper pulleys  70 ,  74  that overlap the horizontal shaft  114  and the groove  112 . A pair of gears  116  are fixed to the horizontal shaft  114  by keys (not shown). The gears  116  mesh with the rack teeth  56  of the vertical racks  54 . Bushings and set collars are mounted on the horizontal shaft  114  in the notches  110  on opposites sides of the gears  116  preventing the gears from moving axially relative to the vertical racks  54  and preventing the horizontal shaft  114  from moving axially relative to the plate  82 . A hex head  118  is secured to the end of the horizontal shaft  114  that projects from the plate  82 . A ratchet wrench  120  having a hex socket  122  that is complementary to the hex head  118  is secured to the conveyor by a tether  124 . By turning the hex head  118  in opposite directions with the-ratchet wrench  120 , the gears  116  are caused to rotate over the rack teeth  56  of the vertical racks  54 . Rotation of the gears  116  in opposite directions causes the gears meshing with the rack teeth  56  to push the upper plates  80 ,  82  and the pulleys  70 ,  74  between the plates upwardly and downwardly along the lengths of the upstream and downstream shafts  40 ,  42 . In this manner, the vertical positions of the pulleys  70 ,  74  on the shafts  40 ,  42  can be easily and quickly adjusted. When the pulleys are in their adjusted positions, a screw threaded knob  126  mounted on the edge of the bottom upper plate  82  can be tightened down against the horizontal shaft  114  of the adjustment mechanism to hold the horizontal shaft  114  against rotation and thereby hold the pulleys  70 ,  74  in their adjusted positions on the vertical shafts  40 ,  42 . Each of the vertical racks  54  are provided with caps  128  at their top ends to prevent the upper plates  80 ,  82  and the upper pulleys  70 ,  74  from being adjusted too high on the vertical shafts  40 ,  42 . 
     Each of the bottom plates  82  have pointers  132  secured thereto that, together with a vertical scale  134 , provide a visual indication of the adjusted position of the pulleys on their shafts. As shown in FIGS. 5 and 8, the pointers  132  are secured to each of the bottom plates  82  in positions pointing out toward an edge of the scale  134 . The scale  134  is mounted on a vertical bar  136  that is secured to an angle bar  138  at its bottom end by a pair of bolts  140  screw threaded into female ratchets  142  with handles  144 . The lower of the two bolts  140  passes through a hole in the vertical bar  136  just large enough to accommodate the bolt. The upper of the two bolts  140  passes through a larger hole  146  in the bar  136 . The larger hole  146  is provided so that both of the ratchets  142  can be loosened and the vertical bar  136  and scale  134  can be pivoted about the lower bolt  140  outwardly away from the shafts and pulleys. This provides more clearance between the scale  134  and adjacent parts of the conveyor such as the pulleys  70 ,  72 , the pointer  132  and the knobs  126  to enable belts to be more easily removed from the pulleys and replaced on the pulleys as needed. 
     Although only the vertical adjustment mechanism of the upper pulleys  70 ,  74  of the first conveyor  10  is described above, it should be understood that the vertical adjustment mechanisms of the upper pulleys  70 ,  74  and lower pulleys  72 ,  76  for both conveyor systems  10 ,  12  on opposite sides of the conveyor path  14  are the same. The vertical adjustment mechanisms of the invention enable the vertical positions of the pulleys on the upstream shaft  40  and downstream shaft  42  to be quickly and easily adjusted, thereby reducing down time of the overall conveyor system improving its time efficiency. 
     While the present invention has been described by reference to specific a embodiment, it should be understood that modifications and variations of the invention may be constructed without departing from the scope of the invention defined in the following claims.