Patent Abstract:
A strapping machine feeds strapping material around a load, positions, tensions and seals the material around the load. The machine includes a work surface, a portion of which is upwardly pivotal. A conveyor mounted within the work surface has a friction belt drive. The conveyor roller closest to the strap chute has a middle portion that has a smaller diameter than the end portions. The middle portions are fitted together to rotate as a unitary element. A load compression assembly is mounted at the strap chute. A side squaring assembly aligns the load in the direction transverse to the load direction. A strap guide extends between a pre-feed assembly and the feed assembly and includes a fixed portion and a movable portion forming a guide path that is opened to access the guide path. An interlocked enclosure is mounted to the machine frame below the work surface to access the sealing head and the feed assembly.

Full Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
   This application is a divisional application of U.S. patent application Ser. No. 11/381,411, filed May 3, 2006 now U.S. Pat. No. 7,240,612. 

   BACKGROUND OF THE INVENTION 
   The present invention is directed to an improved strapping machine. More particularly, the present invention is directed to a strapping machine having an improvements in conveyance and handling of loads in the machine and access to internal systems for maintenance. 
   Strapping machines are in widespread use for securing straps around loads. One type of known strapper includes a strapping head and drive mechanism mounted within a frame. A chute is mounted to the frame, through which the strapping material is fed. 
   In a typical stationary strapper, the chute is mounted at about a work surface, and the strapping head is mounted to a horizontal portion of the chute, below the work surface. The drive mechanism is also mounted below the work surface, near to the strapping head. The drive mechanism “pulls” or feeds strap material from a source, such as dispenser into the machine. The drive mechanism urges or feeds the strap through the strapping head, into and around the chute, until the strap material returns to the strapping head. The drive mechanism also retracts the strap material to tension the strap around the load. 
   It has also been found that it is often necessary to access the strapping head (and more specifically the weld head) by removing portions of the work surface. This may be necessary to dislodge misfed strap, to clear the strapping head or weld head, or for general maintenance or repair of the machine. Quite often, it is necessary to access the strap path (by moving the strap chute) at the weld head. 
   Often strapping machines are positioned or located in a product line such that the working surface of the strapper is at a higher elevation than a conventional work surface. In such instances, it can be difficult to open the various panels and the like to permit access to the internal portions of the machine. This is particularly the case with moving or removing the working surfaces of the strapper to access the strapping head and the feed/retraction mechanism. 
   Many such machines are employed in processes that maximize the use of fully automated operation. To this end, machines are configured for automated in-feed and out-feed, such that a load (to be strapped) is automatically fed into the machine by an in-feed conveyor, the strapping process is carried out, and the strapped load is automatically fed out of the machine by an out-feed conveyor. However, there may be times that loads are physically too small to be moved into the strapping area by known conveyors, or other times that loads come into the strapping area that are askew and require squaring or straightening, or may need to be compressed before being strapped. 
   Accordingly there is a need for an improved strapping machine that facilitates package or load handling and strapping. Desirably, such a machine facilitates the handling and strapping of loads that may otherwise be difficult to handle. More desirably, such a machine eases movement or removal of the work surfaces to access the internal portions of the machine. 
   BRIEF SUMMARY OF THE INVENTION 
   A strapping machine is configured to feed a strapping material around a load, position, tension and seal the strapping material around the load. The machine includes a work surface for supporting the load. At least a portion of the work surface is upwardly pivotal. 
   A conveyor is mounted within the work surface that has a friction belt drive. The conveyor includes a pair of end rollers that define a plane and the conveyor rollers are engaged by the belt along the plane. Intermediate rollers are disposed between the end rollers. A tension roller maintains tension in the belt. The conveyor is configured so that a load present on the conveyor increases a force between the conveyor rollers and the drive belt to drive the conveyor. 
   A strap chute carries the strapping material around the load and releases strap from the strap chute. A load compression assembly is mounted to the frame and disposed above the work surface. The compression assembly includes a reciprocating gate that moves toward the work surface to contact and compress the load prior to conveying the strap around the load. The gate is actuated by a rod-type cylinder operably connected to the machine frame and to an uppermost point on the gate. The cylinder and rod are below the uppermost point of the gate when the gate is in the feed or the compressed state. Preferably, the cylinder is enclosed within the arch enclosure of the chute. The gate can be formed from a transparent or translucent material to permit viewing the load through the gate. 
   The conveyor roller closest to the strap chute has end portions and a middle portion that has a smaller diameter than the end portions. The end and middle portions are fitted together to rotate as a unitary element. The roller includes a pair of spindles, one in each end portion extending toward the middle portion. The spindles are rotatable independent of their respective end portions and independent of one another. 
   The machine includes a side squaring assembly that aligns the load in the direction transverse to the load direction. The side squaring assembly includes a pair of side plates that substantially simultaneously move toward one another to square the load on the conveyor. The side squaring assembly includes a drive having a pair of substantially mirror image cylinders 
   The side plates can each include a forward squaring plate mounted to the side plate transverse to the side plate. The forward squaring plate squares the load in the machine direction. The machine can also include a longitudinal squaring drive having a pair of rotating engaging elements for squaring the load in a longitudinal direction. Load contact elements are loosely mounted to the rotating engaging elements such that the load is driven forward by the contact elements when there is low resistance to movement and when the load resists movement the contact elements stop and the rotating engaging elements rotate freely of the stopped contact elements. 
   A strap guide extends between the pre-feed assembly and the feed assembly and includes a fixed portion and a movable portion. The movable portion moves toward and away from the fixed portion to form a guide path that is opened to access the guide path. 
   An enclosure is mounted to the machine frame below the work surface. The sealing head and the feed assembly are located within the enclosure and are accessed by an interlocked, openable access panel and an interlocked access door on the panel. 
   These and other features and advantages of the present invention will be apparent from the following detailed description, in conjunction with the appended claims. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     The benefits and advantages of the present invention will become more readily apparent to those of ordinary skill in the relevant art after reviewing the following detailed description and accompanying drawings, wherein: 
       FIG. 1  is a perspective view of a strapping machine illustrating in phantom a work surface lift system of the present invention; 
       FIG. 2  is a partial perspective view of the underside of the work surface illustrating the lift lever and arm; 
       FIG. 3  is view of the lever and arm showing the arm engaging the work surface; 
       FIG. 4  is a perspective view of the strapping machine illustrating in phantom a load weight engaging conveyor system of the present invention; 
       FIG. 5  is an enlarged, partial perspective view of the weight engaging conveyor system with a single roller in place; 
       FIG. 6  is a top perspective view of the conveyor system with the rollers removed for ease of illustration; 
       FIG. 7  is an exploded view of the conveyor system again, with the rollers removed for ease of illustration; 
       FIG. 8  is a bottom view of the drive assembly for the conveyor system; 
       FIG. 9  is an exploded view of the conveyor system, rollers and support elements; 
       FIG. 10  is a perspective view of the strapping machine illustrating a load compression system of the present invention; 
       FIG. 11  is a partial perspective view of the load compression system frame and support assembly illustrating the cylinder mounting arrangement; 
       FIG. 12  is a partial view of a corner of the compression screen showing the cylinder mount; 
       FIG. 13  is a illustrates an outside wall of the compression mount frame; 
       FIG. 14  is an enlarged view of the cylinder mount; 
       FIG. 15  is a view of the compression mount cylinder in the retracted state; 
       FIG. 16  is an enlarged view of a section of the compression assembly; 
       FIG. 17  is a perspective view of the strapping machine illustrating a load side squaring system of the present invention; 
       FIG. 18  is a perspective view of the squaring system illustrating the squaring plates and machine rollers; 
       FIG. 19  is a bottom perspective view of the squaring system illustrating the drive system; 
       FIG. 20  is a top perspective view of the system with the rollers removed for ease of illustration; 
       FIG. 21  is a perspective view of the strapping machine illustrating a load stack friction drive system of the present invention; 
       FIG. 22  is a perspective view of the system as it is on the machine rollers; 
       FIG. 23  is a front view of the load stack friction drive system; 
       FIG. 24  is a perspective view of the strapping machine illustrating a conveyor nose roller of the present invention; 
       FIG. 25  is a perspective view of the nose roller positioned in the conveyor, adjacent to the area at the strapping head; 
       FIG. 26  is an enlarged partial view of the nose roller; 
       FIG. 27  is a perspective view of the nose roller removed from the conveyor system; 
       FIG. 28  is an exploded view of the nose roller; 
       FIG. 29  is a perspective view of the strapping machine illustrating in phantom a strap guide and opening system of the present invention; 
       FIG. 30  is a partial view of the strap guide and opening system with the guide in the open state; 
       FIG. 31  is a view similar to that of  FIG. 30  with the guide in the closed state; 
       FIG. 32  is a perspective view of the strapping machine illustrating in phantom a drop down front enclosure panel; 
       FIG. 33  is a partial view of the drop down panel; 
       FIG. 34  is a partial view of the frame sides showing the hinges and interlocks; 
       FIG. 35  is another partial view illustrating the panel interlock; 
       FIG. 36  is a view of the panel side; 
       FIG. 37  shows, in phantom, the slide action of the access door within the drop down panel; 
       FIG. 38  illustrates the access to and action of the lift arm; 
       FIG. 39  illustrates the interlock on the access door; 
       FIG. 40  illustrates the door residing in the drop down panel in phantom; and 
       FIG. 41  illustrates the rear of the access door as it resides within the panel. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described a presently preferred embodiment with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiment illustrated. 
   It should be further understood that the title of this section of this specification, namely, “Detailed Description Of The Invention”, relates to a requirement of the United States Patent Office, and does not imply, nor should be inferred to limit the subject matter disclosed herein. 
   Referring to the figures and in particular  FIG. 1 , there is shown generally a strapping machine  10  embodying the principles of the present invention. The strapping machine  10  includes, generally, a frame  12 , a strap chute  14 , a feed assembly  16  and a weld head  18  (both shown briefly in  FIG. 25 ). A controller  20  provides automatic operation and control of the strapper  10 . A table top or work surface  22  is disposed on the strapper  10  at the bottom of the chute  14 . The work surface  22  is configured as a conveyor  24  and will be discussed in more detail herein. A strap supply or dispenser  26  supplies strapping material S to the feed assembly  16  and weld head  18 . 
   The work surface  22 , again as will be discussed below, is configured having in-feed and out-feed conveyors  28 ,  30  that are formed as part of the work surface  22  and pivot upwardly and outwardly (relative to the strap chute  14 ) to provide access to the internal components, e.g., the feed assembly  16  and the weld head  18 . This is often necessary to conduct maintenance or inspection of these areas. It will also be appreciated that the work surface  22  is often at a height that is greater than a conventional work surface height. That is, the work surface  22  is positioned at a height that is complementary to the other aspects of whatever operation the strapper  10  is part of. As such, the work surface  22  could be at a height that makes it difficult to lift the conveyors  28 ,  30  to access the internal components. 
   The present strapping machine  10  includes a novel work surface lift system  32  to facilitate lifting the conveyors  28 ,  30  to raise and hold them in an open condition. As seen in  FIGS. 2 and 3 , the lift system  32  includes an arm  34  that is pivotally mounted to the frame at an arm pivot  36 . The arm  34  includes a lever portion  38  that extends from an end  40  of the arm  34 , about transverse thereto. The lever portion  38  has a roller  42  mounted at a free end  44  that engages a lip edge  46  of the conveyor  28 ,  30 . The pivot  36  is defined at the juncture  50  of the lever portion  38  (at about the elbow), at which the arm  34  is mounted to the frame  12 . A hand grip portion  52  is mounted to an opposite end  54  of the arm  34  (opposite of the lever portion  38 ) and is used to manually operate the arm  34 . The grip  52  (arm) is accessed from a front access door  56  in the access panel  58  of the machine enclosure  60  for ease of use. 
   The hand grip  52  is pulled toward the front of the machine  10  (toward the operator). The mechanical advantage afforded by the longer travel of the arm  34  facilitates lifting of the work surface  22  (conveyor  28  or  30 ) by the shorter lever portion  38 . A cylinder  62  serves to maintain the arm  34  in the engaged (lifted) position and a spring  64  aids in providing the force to return the surface  22  to the closed condition. When in the open state, the lever roller  42  engages a notch  66  formed in the lip edge  46  of the conveyor  28 ,  30  to prevent the lever roller  42  from slipping along the lip  46  (to inadvertently close). 
   A load weight engaging conveyor drive system  68  is illustrated in  FIGS. 4-9 . The system  68  is configured so that the conveyor rollers  70  are driven as the weight on the rollers  70  (the conveyor section) increases. The drive system  68  includes a motor  72 , preferably a direct current (DC) driven motor that drives a drive belt  74 . The belt  74  is maintained in a generally planar state (relative to the conveyor  28 ,  30  and rollers  70 ) by a pair of end rollers  76  that define a plane P 76  at about their peripheries and intermediate rollers  78  that are also, at their peripheries, about at the end roller plane P 76 . 
   The belt  74  encircles the rollers  76 ,  78  and a drive roller  80  on the motor  72 . A tension roller  82  is mounted to a pivoting arm  84  that is biased (by a spring  86 ) to maintain tension in the belt  74 . The motor  72  and the rollers (the end  76  and intermediate  78  rollers) are mounted to a carriage or frame  88  that is mounted to the pivoting work surface  22  (conveyor sections  28 ,  30 ) to facilitate maintenance on or removal of the drive system  68 . 
   The frame  88  includes slots  90  in which the conveyor roller ends (spindles  92 ) reside during operation. A cover  89  is configured and positioned to prevent the conveyor roller spindles  92  from being displaced when the work surfaces  22 ,  24  are pivoted upwardly. In present embodiment, cover  89  has slots  91  in which the roller spindles may also reside. The roller spindles  92  “float” in the slots  90 , and in the present embodiment, slots  91 , so that the rollers  70  “float” on the drive belt  74 . In this manner, the normal force between the rollers  70  and the belt  74  is created by the weight of the rollers  70  combined with the load L on the belt  74 . It will be appreciated that the conveyor rollers  70  sit along a top or outer surface  94  of the belt  74  while the end and intermediate rollers  76 ,  78  (those that are part of the drive  68 ), sit along a bottom or inner surface  96  of the belt  74 . In addition, the location at which the conveyor rollers  70  sit on the belt  74  is between adjacent end/intermediate rollers  76 ,  78  and, likewise, the end/intermediate rollers  76 ,  78  support the belt  74  between adjacent conveyor rollers  70 . In this manner, the conveyor rollers  70  are in effect cradled by the belt  74  between drive rollers  76 ,  78 . A bracket  79  is attached to the conveyor frame  88  with the belt  74  positioned between the bracket  79  and the frame  88 . The bracket  79  is in turn mounted to the conveyor cover  89 . 
     FIGS. 10-16  illustrates a load compression assembly  98 . Load compression is provided by a compression gate  100  that is actuated by a cylinder  102 , located on a side of the gate  100 . The compression assembly  98  is configured to compress the load L prior to strap S being positioned and tensioned around the load. This reduces the amount of strap that has to be fed out and in turn retracted to strap the load. It also provides a pre-load on the load which in turn reduces the amount of work that has to be done by the feed and strapping (weld) heads  16 ,  18 . 
   As set forth above, compression gate drive is provided by a rod-type cylinder  102 , located on a side of the gate  100 . The cylinder  102  is mounted within the chute arch enclosure  104 , which is the frame structure that houses the strap chute  14 . In this manner, one end  106  of the cylinder  102  is mounted to the frame  12  at about the work surface elevation  22  and the other end  108  (the rod) is mounted to the gate  100 . Accordingly, no additional space is required, nor addition structure required to house the gate  100  and cylinder  102  above the topmost extension of the gate  100 . Advantageously, this reduces the overall head space required for the compression assembly  98 , and when the gate  100  is in the lowered position (e.g., the compression position), the cylinders  102  are fully retracted and thus the overall machine  10  height is less than known machines (that have overhead mounted cylinders). 
     FIGS. 17-20  illustrate a side squaring system  110  that is configured to square the lateral sides of a load L and to restrain the forward movement of the load (which in effect squares the longitudinal (front) edges of the load. The squaring system  110  includes a pair of opposed laterally moving side squaring plates  112 . In the illustrated embodiment, both side plates  112  have forward edge squaring plates  114 , however, it will be recognized that the forward squaring plate  114  can be present on only one of the side plates  112  and will function effectively. 
   The side plates  112  are mounted to a drive system  116  that is mounted to the machine  10  below the rollers  70 . In this manner, the drive mechanism  116  does not interfere with the operation of the strapper  10 . It will also be appreciated that the side squaring system  110  is mounted upstream (forward) of the strap chute  14 , again so that it does not interfere with the operation of the strapper  10 . 
   The drive system  116  is configured to move laterally (sideways) to square the sides of the load L. For example, when strapping magazines, the load can be moved up to the side squaring system  110  and the side plates  112  moved inward so that the leading ends (edges) of the magazines square up to the forward squaring plates  114 . The side plates  112  can then move further inward to square up the side edges of the magazines. Once the forward and side edges are squared, the side plates  112  can be retracted and the load can be conveyed forward into the strap chute  14 . 
   The drive system  116  is configured to move the side plates  112  simultaneously toward and away from each other so that squaring is carried out relatively symmetrically. Accordingly, the drive  116  includes a pair of rod-type cylinders  118  mounted in mirror image relation to one another with the rod ends  120  mounted to the plates  112  (to laterally move the plates  112 ) and the cylinder ends  122  fixed within the assembly carriage  124 . The rod ends  120  are mounted to bearing plates  126  that traverse along rod bearings  128  to provide smooth movement of the plates  112 . As seen in  FIGS. 18 and 20 , the side plates  112  are mounted to the bearing plates  126  by supports  129  that are positioned and extend up from between rollers  70  so as to prevent any interference. 
     FIGS. 21-23  illustrate a longitudinal squaring drive  130  that functions with the forward edge squaring plates  114 . The forward squaring drive  130  includes a pair of opposing, rotating central elements  132  and a plurality of loosely mounted rotating rings  134 . The drive element  132  and rings  134  are formed from a resilient, low friction material, such as neoprene or the like. The rings  134  are loosely mounted or fitted to their respective drive elements  132  so that the rings  134  will rotate when they are in contact with the central drive element  132 . However, when the friction or contact force between the rings  134  and the load L or material being driven is too great, the rings  134  will not rotate. Rather the friction between the rings  134  and the load L is too great to permit the rings  134  to move. Accordingly, when, for example, a load of material (such as the exemplary magazines) is introduced to the forward squaring drive  130 , the magazines that may be out of longitudinal (forward to rearward) alignment contact the rotating rings  134  and are driven into the forward squaring plates  114 . When, however, the magazines contact the forward squaring plates  114 , the friction that results at the rings  134 /magazine interface is too great for the rings /drive element  134 / 132  to overcome, and the rings  134  stop rotating relative to the drive elements  132 . 
     FIGS. 24-28  illustrate a necked-down roller  136 . It will be appreciated that the roller or those rollers closest to the strap chute often cannot be full length rollers due to interferences or, as illustrated, plates P that may overlie a portion of the chute at about the strapping head. Because these rollers are not full length (that is, they do not fully extend across the conveyor), they are not driven rollers. Instead, these rollers are idler or passive rollers that only provide a bearing surface across which the package can move. This can be problematic, especially with smaller items or packages that are not sufficiently long to extend from one driven roller (on the infeed side), across the chute area, and on to the next driven roller (on the outfeed side). 
   The present necked-down roller  136  overcomes these drawbacks by providing a roller having a smaller diameter portion at about the middle of the roller  138  and larger outer sections  140  (that are the same diameter as the other rollers  70 ) that is driven together with the remaining rollers  70  on the conveyor  28 ,  30 . In this manner, accommodation is made for the interference (plate  142 ) while still maintaining the roller outer sections  140  at the same diameter so as to properly convey smaller loads into the strapper chute  14  area. 
   The roller  136  outer roller sections  140  are the same diameter as the other rollers  70  of the conveyor  28 .  30 . The middle, necked-down transition section  138  bridges the two outer sections  140 . A spindle  144  extends through each of the outer roller sections  140  from the end  146  of the outer section  140  to a bearing  148  at the necked-down transition  138 . The spindles  144  are held within the roller sections  138 ,  140  by a plurality of bearings  148 ,  150 , which as illustrated, can include inner and outer bearings on each of the outer sections  140 . Accordingly, the outer sections  140  can rotate while the spindles  144  remain fixed with the ends  152  residing within the conveyor drive frame slots  90  (see  FIG. 5 ). The smaller diameter transition section  138  is press-fit to the outer sections  140  so that the entirety of the roller  136  functions as a single element with the stationary spindles  144 . 
     FIGS. 29-31  illustrate a strap guide and opening system  154  that is configured for a machine  10  such as the elevated work surface  22  machine discussed above. The opening strap guide  154  provides a pathway (indicated generally at  156 ) through the machine  10  from the supply  26  to the strapping head (or the feed system  16 ) so that the strap S can traverse in a controlled and unobstructed manner. Such a guide  154  is important to prevent the strap from twisting, kinking or otherwise jamming as it is fed from the strap supply  26 . 
   It is also important to be able to access the guide  154  so that strap S can be removed as needed (e.g., sections of jammed strap material). Accordingly, the present strapper guide  154  has a drop down access section  158  that extends from a pre-feed assembly  160  (which is a driven element that is located at the inlet to the machine  10 ) to the feed head  16 . The guide  154  is formed from an upper guide portion  162  that remains stationary and the lower movable guide portion  158 . The lower guide portion  158  is actuated (moved) by movement of a handle  164  and moves along a pair of pins  166  that are fixed to the machine  10 . The lower guide  158  has arcuate slots  168  along which the guide  158  moves between the open position ( FIG. 30 ) and the closed position ( FIG. 31 ). The arcuate slot  168  shape (as opposed to linear, e.g., vertical shape) provides for lateral movement of the lower guide  158  away from the pre-feed assembly  160  (as the guide  154  is opened) to provide better access in and around the pre-feed  160  area. And in that the strap S is fed about a roller  170  at the feed head  16  (exiting the guide  154 ), the movement of the lower guide  158  away from the roller  170  at the feed head  16  entrance does not adversely effect strap moving along the strap path  156 . 
     FIGS. 32-41  are a series of illustrations showing the front enclosure  60 , the enclosure access panel  58  and the access panel door  56  and the interlocks  172 ,  174 , respectively, for the panel  58  and door  56 . As seen in  FIG. 32 , the enclosure panel  58  (which includes the door  56 ) is mounted to the machine frame  12  by hinges  176  to allow the panel to pivot downwardly from the frame  12  to provide complete frontal access to the machine enclosure  60 . The panel  58  includes pins  178  that extend outwardly from the lower sides of the panel  58  that are received in hinge sleeves  180  in the frame  12 . The panel  58  includes interlocks  172  on the frame  12  ( FIG. 34 ) and the panel  58  ( FIG. 36 ) that isolate power to the machine  10  when the interlock elements  172  are disengaged from one another. 
   Likewise, the access door  56 , which is a two-piece sliding door that slides within a track  173  in the panel  58 , also includes interlocks  174  on the door  56  ( FIG. 39 ) and in the door frame  182 , which is within the enclosure panel  58  ( FIG. 35 ) that isolate power to the machine  10  when the interlock elements  174  are disengaged from one another. It will be appreciated that both the lift arm  34  and the guide opening handle  164  are accessible from either the open access door  56  or the lowered enclosure panel  58 . 
   All patents referred to herein, are hereby incorporated herein by reference, whether or not specifically done so within the text of this disclosure. 
   In the present disclosure, the words “a” or “an” are to be taken to include both the singular and the plural. Conversely, any reference to plural items shall, where appropriate, include the singular. 
   From the foregoing it will be observed that numerous modifications and variations can be effectuated without departing from the true spirit and scope of the novel concepts of the present invention. It is to be understood that no limitation with respect to the specific embodiments illustrated is intended or should be inferred. The disclosure is intended to cover all such modifications as fall within the scope of the claims.

Technology Classification (CPC): 1