Abstract:
A strap joint rotating assembly is for use with a strapping machine. The strapping machine has a feed head for feeding the strapping material into the strapping machine, a strap chute through which the strapping material is passed and a sealing head to seal overlapping courses of the strapping material to one another to define a strap loop having a seal and defining a strap loop plane. The strap joint rotating assembly includes a driven wheel having an axis of rotation generally perpendicular to the strap loop plane and a pinch wheel that has an axis of rotation and is carried on a wheel block. The wheel block pivots to move the pinch wheel into and out of the strap loop plane. The pinch wheel, when in the strap loop plane, has its axis of rotation parallel to the axis of rotation of the driven wheel. The pinch wheel is further movable toward the driven wheel to pinch the strap between the driven wheel and the pinch wheel. The driven wheel is driven to rotate the strap loop around the load.

Description:
BACKGROUND OF THE INVENTION 
   The present invention is directed to a strap joint rotator. More particularly, the present invention is directed to a strap joint rotator having a pinch wheel with a pivot linkage used with a strapping machine for compressible materials. 
   Strapping machines are known for securing straps around compressible loads such as cotton bales or other textile materials. To properly contain the bales, multiple straps are often used, e.g., fed, tensioned and sealed around the load, to create the baled load. Typically, such bales are strapped with plastic strap material. 
   A strapping machine that is used to conform the bale includes a frame on which the various strapping components are mounted. Several separate but interdependent feed and sealing or strapping heads, strap chutes and other components for positioning the multiple straps around the load are mounted to the frame. Each strapping unit operates in conjunction with each other unit so that the strapping occurs simultaneously at each of the several units. In this manner, the strapping operation is carried out in an efficient and time effective operational mode. 
   The baling machine includes a hydraulic press that compresses the bale prior to strapping the bale. As such, with the bale compressed prior to strapping, the bale is much more stable. An upper or compression platen forms part of the upper strap chute leg and the strapping components are mounted within a side leg of the strap chute. To effect baling, the upper platen contacts and compresses the load (which completes or closes the strap chute around the load), strap is fed through a sealing head, through the chute around the load, and back to the sealing head. At the sealing head overlapping courses of strap are sealed to one another, the strap is cut from its source (supply) and the compression platen is moved away from the bale to allow the bale to expand. 
   As the compression plate or platen is released, the material expands to “fill” the loop created by the sealed strap. As such, the expanding material creates a stress (a strain) in the strap. The stress is higher in the direction of expansion of the load. Moreover, the side of the bale is often that portion of the bale that is the “bottom” of the load for purposes of shipping, handling and storage. As such, given that the seal is formed at the side of the bale, the seal may be at that portion of the strap that is in a higher stress area and is in contact with the ground or other object and can possibly be damaged. 
   To address these concerns, one strapping (baling) machine is configured with a device that repositions the strap on the load. The device, which is a strap joint rotator, repositions the strap to relocate the seal along the bottom or top of the load to reduce the stress that is exerted on the strap joint. Such a strap joint rotator uses multiple driven assemblies, mounted to a shifting carriage. The carriage moves the assemblies into and out of the strap path subsequent loop formation and prior to expansion of the load. Such a strap joint rotator is disclosed in Bullington, U.S. patent application Ser. No. 11/782,120, which application is commonly assigned with the present application and is incorporated herein by reference. 
   In this arrangement, the rotator assemblies are mounted to a carriage that reciprocates all of the assemblies into and out of the strap path. Although such an arrangement has been found to work well for rotating the strap joint, the assemblies are large and relatively heavy and can exert unneeded stresses on the strapping machine. Moreover, the laterally moving rotator assemblies can inadvertently move the straps laterally, out of the strap path. 
   Accordingly, there is a need for a multi-head strapping machine for compressible loads that includes a strap joint rotator that exerts lesser stresses on the strapping machine. Desirably, such a strap joint rotator facilitates and assists in maintaining the strap joint aligned in the strapping portion of the machine. More desirably, such a strap joint rotator is of a sufficiently small profile to minimally, if at all, impact the machine size. 
   BRIEF SUMMARY OF THE INVENTION 
   A strap joint rotating assembly is used with a strapping machine of the type for feeding a strapping material around a load, positioning, tensioning and sealing the strapping material around the load. The joint rotator is anticipated for use with strapping machines for strapping compressible loads. 
   The strapping machine is a side sealing machine that has a feed head for feeding the strapping material into the strapping machine, a strap chute through which the strapping material is passed and a sealing head to seal overlapping courses of the strapping material to one another to define a strap loop having a seal and defining a strap loop plane. The strap traverses from the feed head, through the strap chute and sealing head to define a strap path. 
   The rotating assembly includes a driven wheel having an axis of rotation generally perpendicular to the strap loop plane and a pinch wheel that has an axis of rotation and is carried on a wheel block. The wheel block pivots to move the pinch wheel into and out of the strap loop plane. The pinch wheel, when in the strap loop plane, has its axis of rotation parallel to the axis of rotation of the driven wheel. The pinch wheel is further movable linearly toward the driven wheel to pinch the strap between the driven wheel and the pinch wheel, such that the driven wheel is driven to rotate the strap loop and the seal around the load. 
   In a present embodiment, the driven wheel is positionally fixed, preferably within a portion of the strap chute, outside of a periphery of the strap loop, and is only rotatable about is axis of rotation. 
   In an embodiment, a wheel support is carried in the wheel block and is mounted in the wheel block for pivotal movement with the wheel block into and out of the strap loop plane and for linear movement within the wheel block toward and away from the driven wheel. The wheel support is biasedly mounted within the wheel block. 
   A compression block can be mounted to the wheel block and positioned such that at least a portion of the wheel support is disposed between the compression block and the wheel block. In such an arrangement, the wheel support is biasedly mounted between the compression block and the wheel block. 
   The wheel block is mounted to a carriage that is mounted to the strapping machine. The wheel block pivots on the carriage into and out of the strap loop plane. A linkage operably connects to the carriage and the wheel block. 
   In a strapping machine in which multiple straps are simultaneously positioned and sealed around the load using multiple strap chutes, strapping and feed heads, a strap joint rotator assembly is associated with each such chute, strapping and feed head unit. In this arrangement, the driven wheels are driven from a common drive to properly execute rotator timing. An actuating bar is configured for reciprocating movement and is operably connected to linkages associated with each pinch wheel. Reciprocation of the actuating bar in a first direction pivots the wheel blocks to move the pinch wheels into their respective strap loop planes, and further movement of the actuating bar in the first direction moves the wheel supports linearly to engage the pinch wheels with their driven wheels. Reciprocation of the actuating bar in the opposite direction moves the wheel supports and pinch wheels away from their driven wheels and rotates the wheel blocks out of their strap path planes. 
   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 schematic illustration of a strapping machine having a strap joint rotator with pivoting linkage and pinch wheel embodying the principles of the present invention, the machine shown with one strapping unit; 
       FIG. 2  is a perspective view of the strapping machine; 
       FIG. 3  is an opposite perspective view of the strapping machine; 
       FIG. 4  is a perspective view of the front or sealing head side of the strapping machine as seen from the inside of the machine; 
       FIG. 4A  is an enlarged view of the area designated in  FIG. 4 , showing the common drive and the actuating bar drive; 
       FIG. 5  is partial perspective view of the pivot assemblies and the drives, with one of the assemblies shown with the enclosure cover removed; 
       FIG. 5A  is an enlarged view of the areas designated in  FIG. 5 , showing the pivot assembly in the engaged position; 
       FIG. 6  is a perspective view of the pivot assembly; and 
       FIGS. 6A-6D  are exploded views of portions of the pivot assembly of  FIG. 6 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   While the present invention is susceptible of embodiment in various forms, there is shown in the figures 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 the 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 to  FIG. 1  there is shown a strapping machine  10  for compressible materials having a pivoting pinch wheel strap rotator  12  in accordance with the principles of the present invention. The machine  10  as shown includes six separate but interdependent strapping units  14   a - f . Each unit  14  includes a feed head  16  (to feed and retract the strap material S), a sealing head  18 , portions of a strap chute  20  including a side leg  22  of the strap chute, a lower portion  24  of the strap chute, an opposite side  26  leg of the strap chute and portions of a transition  28  to an upper portion  30  of the strap chute. It should be noted that the strapper  10  shown in  FIGS. 2-3  is illustrated with a test frame T to accommodate testing of the apparatus and the such a test frame T is not part of the operating strapper  10 . 
   An upper compression platen  32  compresses the load L for strapping and includes the upper portion  30  of the strap chute. Also illustrated, for purposes of understanding, in phantom lines, is the bale of strapped material L. It will be understood that although the components of each of the units  14  are presented in singular, the present machine  10  includes six of each of these components, each associated with one of the strapping units  14   a - f.    
   Referring to  FIGS. 4-6 , the strap rotator or strap joint rotator is illustrated generally at  12 . A strap rotator  12  is associated with each of the strapping assemblies  14 . The rotator  12  includes a driven wheel  34  positioned within a fixed portion of the strap chute  20  at a transition  28  of the chute from the side leg  22  to the upper leg  30  (which is within the platen  32 ) and a pinch wheel  36  that moves into and out of engagement with the driven wheel  34 . The driven wheel  34 , which is located just at an outer periphery of the strap path P, is commonly driven with the other driven wheels  34  by a common drive shaft  38 . 
   A rotator drive  40  is located at a side  42  of the strapping machine  10 . A belt  44  is positioned around a plurality of wheels  46 , one of which  46  is positioned on the drive  40  and another  46  on the drive shaft so that each of the driven wheels  34  is driven at the same speed as each other. The pinch wheel  36  is mounted on a pivot assembly  48  for movement into and out of engagement with the driven wheel  34 . The pivot assembly  48  includes a pivot carriage  50  that is mounted within a covered enclosure  52  (e.g., has a removable cover  54 ) to prevent contamination and to enclose the moving (pivoting) parts. 
   Referring to  FIGS. 6A-6D , the pivot carriage  50  includes a pair of pivot pins  56 ,  58  extending therefrom. A wheel block  60  is pivotally mounted to the pivot carriage  50  at one of the pivot pins  56 . The wheel block  60  includes a lower recess  62  into which a wheel support  64  is mounted. The wheel block  60  includes a front stop surface  66  to, as will be described below, stop forward rotation of the wheel block  60 . The wheel support  64  is mounted to the block  60  by a pivot pin  68  at a rear end of the support  64 . Importantly, the openings  69  in the wheel block  60  through which the pin  68  traverses are slotted. This permits the pivot end  71  of the wheel support  64  to move up and down as well as to pivot. 
   A stub  70  extends from a front of the wheel support  64  on which bearings  72  and the pinch wheel  36  are mounted for free rotation of the pinch wheel  36 . A compression spring  74  is positioned between wheel support  64  and the wheel block  60  to bias the wheel support  64  away from the wheel block  60 . 
   A compression block  76  is pivotally mounted at pivot  78 , to the wheel block  60  at about an intermediate location, as indicated at about  80 , along the compression block  76  such that the wheel support  64  is maintained in the wheel block recess  62  by the compression block  76  (the compression block  76  also fits, in part, in the wheel block recess  62 ). The compression block  76  includes a recess  82  and a lower spring retainer surface  84 . A channel  86  is formed at an end of the recess  82  that opens to the lower spring retainer surface  84 . 
   A lower pivot clevis  88  is fitted into the compression block recess  82  such that a narrowed forward end  90  of the lower pivot clevis  88  extends through the compression block channel  86  and onto the lower spring retainer surface  84 . A rear end of the lower pivot clevis  88  is mounted to the compression block by a pivot pin  92 . In this arrangement, the lower pivot clevis  88  is maintained in the compression block  76 , but is allowed to pivot with the compression block  76 . 
   A spring retainer  94  is positioned on the lower spring retainer surface  84  and includes a notch  96  therein such that the spring retainer  94  fits over the pivot clevis forward end  90  and rests on the lower spring retainer surface  84 . The spring retainer  94  is secured to the pivot clevis  88  by a pivot pin  98  to allow the spring retainer  94  to pivot on the pivot clevis  88 . 
   A threaded rod  100  is positioned in an opening in  102  the lower spring retainer surface  84  and abuts or contacts the narrowed pivot clevis forward end  90 . A lock nut  104  is threaded onto the rod, below the lower surface to secure the rod  100  at a desired threaded depth. 
   A die spring  106  is positioned on the spring retainer  94  and is fitted between the retainer  94  and the wheel support  64 . This maintains a bias between the lower pivot clevis  88  and the wheel support  64 . In this manner, the wheel support  64  floats in the wheel block recess  62  between the wheel block  60  and the compression block  76 , and is maintained in place by the compression spring  74  and the die spring  106 . The thread depth of the rod  100  can be changed to adjust the compression in the die spring  106  by varying the distance between the retainer  94  (pivot clevis  88 ) and the lower spring retainer surface  84 . 
   An actuating link  108  is a three-point link and is mounted at one point  110  to the carriage  50  (a fixed pivot) and is mounted at a second end  112  to an actuating bar  114  that connects the pivot assemblies  48  to one another. The actuating bar  114  is actuated by a cylinder  116  that is mounted to the strapping machine  10 . Pivot pins  118  connect the actuator bar  114  to each of the pivot assembly actuating links  108 . 
   The third position  120  on the actuating link  108  is pivotally mounted to a pivot link  122 . The pivot link  122  is mounted at its other end  124  to the back end  126  of the compression block  76  by pin  129  (just above where the pivot clevis  88  is mounted to the compression block  76 ). 
   The pivot assembly  48  moves through two movements into one of three positions. The two movements can be viewed as an arcuate movement and a linear movement. The first or arcuate movement pivots the entire assembly  48  from a disengaged position (a first position) in which the pinch wheel  36  is out of the plane P P  of the strap path P to bring the pinch wheel  36  into the strap path plane P P . In this second position (or guide position), the pinch wheel  36  lies in the plane P P  of the strap path P, but is not engaged with the drive wheel  34 . The axes of the driven wheel A 34  and the pinch wheel A 36  are essentially parallel when the pinch wheel  36  is in the guide position. 
   The second or linear movement is at the end of the first movement and moves the pinch wheel  36  from the guide position to bring the pinch wheel  36  into engagement with the driven wheel  34  (or the strap S when it is positioned between the wheels  34 ,  36 ), in an engaged position. This parallel movement is to prevent the pinch wheel  36  from contacting the driven wheel  34  (and the strap S) at a corner first, and then “rolling” the remainder of the pinch wheel  36  into contact with the driven wheel  34  (and/or strap S). 
   To this end, it will be appreciated that movement of the actuating bar  114  in the direction indicated by the arrow at  128 , rotates the actuating link  108  counterclockwise which moves the pivot link  122  up, to pivot the rotator pivot assembly  48  (pivot wheel block  60 ) counterclockwise, out of the plane P P  of the strap path P to the disengaged position. 
   Conversely, when the actuating bar  114  reciprocates in the direction opposite the arrow  128 , the actuating link  108  is rotated clockwise. This pushes the pivot link  122  down, which pivots the rotator pivot assembly  48  (pivot wheel block  60 ) clockwise. The wheel block  60  pivots about the pivot indicated at  56 . This brings the pinch wheel  36  into the plane P P  of the strap path P (moves the pinch wheel  36  from the disengaged position to the guide position). It will be appreciated that this movement defines an arcuate path (see  FIG. 6 , arrow at  132 ), and as such, the axis of rotation A 36  of the pinch  36  wheel is non-parallel to the axis of rotation A 34  of the driven wheel  34 . The arcuate movement is stopped by the contact of the stop surface  66  with the fixed portion of the strap chute  20  at the transition  28 , the engagement location being indicated generally by the arrow at  130 . 
   As the actuating bar  114  continues to move in the direction opposite the arrow at  128 , the forward movement of the wheel block  60  is stopped by contact between the stop surface  66  and the chute transition  28 . At this point in the cycle, the pivot assembly  48  (e.g., the pinch wheel  36 ) is in the guide position. However, as the pivot link  122  continues to push down on the end of the compression block  76  (see arrow at  134 ), because the wheel support  64  is captured between the wheel block  60  and the compression block  76 , the downward force from the compression block  76  is transmitted into an upward force on the wheel support  64 . Since the wheel support  64  is biasedly supported between the wheel block  60  and the compression block  76 , and because the openings  69  in the wheel block  60  through which the wheel support pivot pin  68  fits are slotted, this results in an upward movement (see arrow at  136 ) of the wheel support  64 , as assisted by the die spring  106 . This linear movement of the wheel support  64  and the pinch wheel  36 , is such that the terminal movement of the pivot wheel  36  from the guide position to the engaged position (to capture the strap S) is a linear movement of the pivot wheel  36 , with the pivot wheel  36  and driven wheel  34  axes A 36 , A 34  parallel to one another so that essentially the entire surfaces of the wheels  36 ,  34  contact one another. 
   In the overall operation of the strapping machine  10 , the load L is loaded into the strapping machine  10  with the frame portions closed and the compression platen  32  in place. The load is compressed. With the load compressed, the rotator pivot assembly  48  is pivoted to the guide position, with the pinch wheel  36  in the plane P P  of the strap path P, but spaced from the drive wheel  34 . 
   The strapping cycle commences with strap S being fed, in a predetermined length, by the feed head  16 , from the strap supply  33  through the sealing head  18 , through and around the strap chute  20  (include the top leg portion  30  in the compression platen  32 ), and back to the sealing head  18 . In the sealing head  18 , the lead end of the strap S is gripped, and the feed head  16  reverses to retract the strap S. Retracting the strap pulls the strap from the strap chute  20  onto the load L. It should be noted that the strap S is retracted, but is not tensioned about the load L. It should also be noted that with the pinch wheel  36  in the guide position, it is spaced from the drive wheel  34  and the pinch wheel  36  actually serves as part of the guide for the strap S to properly traverse through the chute  20 . This prevents the strap S from being inadvertently misdirected out of the chute  20  at about the transition  28  from the side leg  22  to the top leg  30  (in the platen  32 ). 
   With the strap S retracted, the intermediate section of the strap is gripped (at this point in the cycle both “ends” of the strap S are gripped), the feed end is cut from the strap supply  33  and the strap courses are welded to one another in the sealing head  18 . 
   The actuator bar  114  then moves to move the rotator pivot assembly  48  from the guide position to the engaged position so that the strap S is captured between the pinch and drive wheels  34 ,  36 , and the drive  40  is actuated to rotate the strap joint J to the desired position. The pivot assembly  48  is then moved to the disengaged position (rotated out of the plane P P  of the strap path P), the compression platen  32  is raised to release the bale L, and the bale L is ejected from the machine  10 . 
   It will be appreciated that when the strap S is rotated, the strap S is still in a relaxed state, that is, prior to the bale L being allowed to expand. It is only after the bale L is allowed to expand that tension is exerted on the strap S. And, because the strap S has been rotated so that the joint J is not in the same direction as the natural expansion of the bale L, less stress is exerted on the joint J. Moreover, the load L is often handled and transported with the bale L on its side. As such, positioning the seal or joint J at the top or bottom of the bale L reduces the likelihood that the seal J will contact the floor or possibly become caught on the floor surface or a load stacked on top of or under the instant bale L. 
   Moreover, in that the present strapping machine  10  uses modular feed and sealing or strapping heads  16 ,  18  (such as those disclosed in Flaum, et al., U.S. Pat. No. 6,755,123 and Flaum et al., U.S. Pat. No. 6,584,892, and their related patents, all of which are commonly assigned with the present invention and all of which are incorporated herein by reference), the machine  10  is readily maintained and less complex than known baling machines. The present strapping machine  10  uses an automatic refeed arrangement, which will be recognized by those skilled in the art. 
   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.