Abstract:
An automatic strap chute opening system for use in a strapping machine of the type having an openable, pivotable work surface for supporting a load to be strapped, and a strap chute defining a strap path through which the strapping material is passed. The chute is disposed in part below the surface and is openable to release the strapping material from the chute during the strapping operation. The chute opening system includes a torsional element operably connected to the strap chute for opening and closing the chute and an actuator operably connected to the torsional element. The coordinated movement of the actuator and torsional element corresponds with the opening or closing of the work surface.

Description:
BACKGROUND OF THE INVENTION 
   The present invention is directed to a strapping machine chute opening system. More particularly, the present invention is directed to a strapping machine having a chute opening system that automatically opens the strap chute upon opening the work surface or table top of the machine. 
   Strapping machines are well known in the art for securing straps around loads. One type of known strapper is a stationary unit that includes a strapping head or weld 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 arrangement, a table-top or work surface is likewise mounted to the frame. 
   In a typical stationary strapper, the chute is mounted from about the work surface, and the strapping head is mounted below the work surface. Strap is fed (by a feed system) from a source or dispenser through the strapping head and chute and back to the strapping head, to pull the strap from the chute to around the load and to tension the strap around the load. 
   In the event a strap error occurs, the faulted strap is ejected from the strapping machine by the feed system. Typically, this process is carried out automatically to reduce operation time and attention. However, there are times that an operator must access the area below the work surface and times at which the operator must open the bottom leg of the chute (adjacent to the strapping head) in order to, for example, clear strap from the chute. 
   One known arrangement that provides both a work surface support function and a chute opening function uses a long, cantilevered arm with a spring that pivots upwardly to assist the opening function. The system is configured such that the spring is substantially tensioned when the work surface is in the down or operating position. 
   One drawback to this arrangement is that a “lighter” work surface is more likely to pivot slightly open which in turn isolates power to the strapper (through a keyed interlock). Moreover, if the work surface is replaced, it must be replaced with a surface of similar weight and configuration. In addition, because the spring is at tension when the work surface is open, the spring might not be able to provide sufficient force to then open the chute. 
   Accordingly, there is a need for a strapping machine having an automatic chute opening system. Desirably, such a system uses a cam surface to leverage the opening of the work surface for opening the chute. 
   BRIEF SUMMARY OF THE INVENTION 
   A strap chute opening system is for use in a strapping machine of the type for feeding a strapping material around a load, positioning, tensioning and sealing the strapping material around the load. A strapping machine includes a frame, a work surface for supporting the load to be strapped, in which the work surface is movable relative to the frame between a closed position and an open position, and a strap chute that defines a strap path through which the strapping material is passed and a portion of which is disposed below the surface The strap chute is openable to release the strapping material from the chute during the strapping operation. A strapping head is disposed below the work surface and a portion of the strapping head is interposed in the strap chute. 
   The chute opening system is automatic and uses a cam surface to leverage the opening of the work surface to open the chute. The opening system includes a torsional element operably connected to the strap chute to move the strap chute between the open and closed positions and an actuator operably connected to the torsional element. 
   The actuator includes a work surface engaging element that engages the work surface and is movable with the work surface between the open and closed positions. The work surface engaging element has a cam surface on a lower portion thereof. 
   The actuator includes a pivoting arm having a first end having a cam engaging element, preferably a roller, and a second end operably engageable with the torsional element. When the work surface is in the closed position, the work surface engaging element is engaged with the work surface and urges the cam surface into engagement with the cam engaging element to pivot the arm. This releases the torsional element and urges the strap chute closed. When the work surface is in the open position, the work surface is moved off of the work surface engaging element and the cam surface is moved out of engagement with the cam engaging element. This moves the second end into engagement with the torsional element (to apply a torque to the torsional element) to open the strap chute. 
   In a present embodiment, a biasing element, such as a spring, biases the pivoting arm into engagement with the torsional element. The torsional element can include a lever mounted thereto that is engaged by the pivoting arm. 
   A preferred actuator includes a guide defining a track for movement of the work surface engaging element. The guide restricts movement of the work surface engaging element in a reciprocating manner. In this arrangement, the cam engaging element lies in the track and engagement of the cam surface with the cam engaging element moves the cam engaging element out of the track. A preferred guide is formed by rollers to permit the work surface engaging element to move (reciprocate) freely through the actuator. 
   In a present embodiment, the work surface engaging element includes an inverted J-shaped channel formed and the actuator includes a pin extending therefrom that engages the J channel. The J channel has an elongated leg and a short leg and the pin resides in the elongated leg as the work surface engaging element moves with the work surface between the open and closed positions. The pin resides in the short leg when the work surface is in the open position and strap chute is in the closed position. 
   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 an exemplary strapping machine having an automatic chute opening system embodying the principles of the present invention; 
       FIG. 2  is an enlarged, partial perspective illustration of the chute opening assembly showing the chute opening torsion bar and lever of the chute opening system; 
       FIGS. 3A-3D  are illustrations of the work surface actuator portion of the chute opening assembly showing the actuator portion (and in the case of  FIG. 3B , the work surface) in the machine operating position; 
       FIG. 4  is an illustration of the actuator portion with the work surface pivoted up or open; and 
       FIG. 5  is an illustration of the actuator portion in the maintenance position in which the work surface is pivoted up or open, but the chute remains closed. 
   

   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  having an automatic chute opening system  12  in accordance with the principles of the present invention. The illustrated machine  10  is a bottom-seal strapper, meaning that the strapping head  14  (or sealing head), which forms the seal of the strap S onto itself is at the bottom of the area  16  into which the load L is positioned for strapping. The strapper  10  includes, generally, the strapping or sealing head  14 , a feed system  18  and a strap chute  20 . A frame  22  supports the various elements of the machine  10 . A dispenser  24  supplies the strap material S to the strapper  10  via the feed system  18  to a feed head (not shown). 
   The strapper  10  includes a table top or work surface  26  on which the load L is positioned during the strapping operation. The top surface  26  can be formed as a pair of flat plate-like elements (as illustrated by  26   a  and  26   b ), or they can be driven or undriven rollers or conveyors. All such types of top surfaces are contemplated to be within the scope and spirit of the present invention. While the top  26  types can vary they can all be removed, generally by pivoting the top surface upwardly and outwardly from the center, generally pivoting about pivot pins  30 . 
   In a typical configuration, the strap S is fed into the strapper  10  by the feed system  18  and is directed through sealing head  14  and into the bottom leg  32  of the strap chute  20 , around the chute  20  and back to the sealing head  14 . Once the strap S reenters the sealing head  14 , a free end of the strap S is held or secured, the feed end is tensioned around the load L, and the overlapping strap courses are sealed to one another as the feed end is severed from the supply. The load L is then discharged from the machine  10 . 
   At times during the strapping cycle, strap jams may occur, or other types of strap misfeeds may occur. Generally, these jams or misfeeds are cleared automatically by an automatic ejection system and the free end of the strap is refeed into the machine also by automatic means (neither of the automatic ejection system or the automatic refeed system are shown). At times, however, the automatic ejection and/or refeed systems may not be able to fully clear the machine. At other times, there may be need to access the strap chute  20  (and the sealing head  14 ) for maintenance, inspection or repair. 
   In order to properly access the strap chute  20  the top surface  26  is removed from the machine  10  or moved away from the chute  20  as by pivoting the top  26  upwardly and outwardly. This provides ready access to strap chute  20  area. 
   To provide easier access to the sealing head  14  and the internal areas of the chute  20 , the chute  20  is configured to automatically open upon opening the top surface  26 . To effect the automatic opening, the machine  10  includes the automatic chute opening system  12 . The system  12  includes a torsion bar  34  and lever  36  (which are known elements) and an actuator  38  that cooperates with the torsion bar  34  and lever  36  to open and close the chute  20 . Referring first to  FIGS. 2 and 3B , the torsion bar  34  is operably connected to the chute  20  such that a turning or twisting motion (as indicated by the arrow at  40  in  FIG. 2 ) on the bar  34  opens the chute  20 . The chute  20  is biased to the closed position so that the “relaxed” state of the torsion bar  34  is with the chute  20  closed and a torque (as indicated at  40 ) is required to open the chute  20 . 
   The lever  36  mounted to the torsion bar  34  operably connects the actuator  38  and the torsion bar  34 . The actuator  38  is “actuated” by the top surface  26  and is mounted to the frame  22  just below the top surface  26 . The actuator  38  includes a housing or chassis  44  having a lever contact arm  46  that is pivotally mounted to the body. In a present embodiment, the arm  46  is L-shaped and is mounted to the housing  44  at a pivot end  48 . A roller  50  is mounted to the pivot end  48  (along the pivot axis A 48 ). A free end  52  of the arm  46  has a roller  54  mounted (the lever roller) thereto that engages the lever  36  to move the lever  36  downward to open the chute  20 . A cam roller  56  is positioned on the arm  46 , at about the heel  58  of the L. 
   A guide  60  is formed within the housing  44  a by a pair of spaced apart rollers  62 ,  64 . The guide rollers  62 ,  64  are fixed so that they do not move or translate relative to their respective axes. One guide roller  62  is about aligned with the roller  50  at the pivot end  48  of the arm  46 . 
   The system  12  includes a top surface contact or engaging element  66  having a body  68  having a top engaging portion  70 , a straight side  72 , and a slightly angled surface  74  that transitions into a cammed lower end  76 . In a present embodiment, the top engaging portion  70  includes a roller  78  to permit free movement of the engaging element  66  along the bottom  80  of the top surface  26  (to reduce binding between the bottom  80  of the surface  26  and the engaging element  66 ). 
   The engaging element elongated body portion  68  resides in the guide  60  that is defined by the guide rollers  62 ,  64 . The guide  60  maintains the engaging element  66  within a “track” (indicated generally at  82 ) so that it reciprocates (see, e.g., directional arrows  84  in  FIGS. 3A and 4 ) with the removal (or pivoting) of the top surface  26 . In a present embodiment, the engaging element  66  includes the top engaging portion  70  which extends generally transverse to the body  68 , and the top engaging portion roller  78  is mounted to a free end  88  of the portion  70 . 
   The body  68  includes a channel  90  that is configured to receive a pin  92  that is mounted to the housing  44 . The channel  92  has an inverted J-shape (the J-channel), that is configured such that the pin  92  resides in the major (elongated) leg  94  of the J-channel  90  when the top  26  is in or moved between the open and closed positions. The shorter leg  96  of the J-channel  90  is a maintenance position, which will be described in more detail below. 
   As set forth above, the engaging element  66  includes a cammed lower end  76 . The cammed end  76  (which is an end having a cam or curved surface), is configured to engage and move the cam roller  56  on the arm  46  to pivot the arm  46  downwardly. As the engaging element  66  is moved upwardly (as by pivoting the top  26  open), the engaging element cam surface  76  comes off of (or disengages from) the cam roller  56  and a spring  98  mounted to the arm  46  (between the lever roller  54  and the cam roller  56 ) biases the arm  46  upward to the chute open position. When in this position (e.g., the arm  46  biased upward), the cam roller  56  is in the track  82  of the rollers  62 ,  64 . Accordingly, as the element  66  is urged down into the track  82 , the cam surface  76  engages the cam roller  56  and the arm  46  is moved downward to close the strap chute  20 . As such it is the action of the cam  76  acting on the cam roller  56  that moves the chute  20  closed, and is not solely a spring force that maintains the chute  20  closed. 
   It will be appreciated that in the known spring-biased only arrangements the extension spring that is used to urge the chute open is in the fully extended position when the top is pivoted down or closed. As such, when the top is down and the chute closed, the spring is fully extended. The result is that the weight of the top is used to maintain the chute closed. This is not so with the present arrangement in which the cam surface  76  engaging the roller  56  moves the lever  36  and torsion bar  34 , and thus the chute  20  to the closed position, and the flat and slightly angled surfaces,  72 ,  74 , respectively, of the element  66  engaging the roller  56  maintain the chute  20  closed. The spring  98  in the system  12  is thus used to urge the cam  76  along the cam roller  56  (to urge the engaging element  66  to the open position) and not to exert a force on the torsion bar  34  or lever  36 . 
   The maintenance position, which is shown in  FIG. 5  provides for the top  26  to be in the open position, but allows the chute  20  to move to the closed position, so that the chute  20  can function in a normal operating mode. This position may be used for certain maintenance, inspection and/or repair situations. When in the maintenance position, the sealing head  14  can be manually indexed through a cycle to further inspect and/or carry out maintenance on the machine  10 . In the maintenance (or service) position, the element  66  is angled, as indicated at α, relative to the track  82  (by virtue of the pin  92  being in the short leg  96  of the J-channel  90 ), which results in the arm  46  being pivoted down (to the closed chute position), but with the top engaging portion roller  78  pivoted upwardly to the top  26  open position. 
   Advantageously, when the top  26  is then closed (from the maintenance position), the top  26  contacts the roller  78  and automatically resets the actuator  38  by moving the engaging element  66  back within the track  82  (so that the pin  92  again resides within the long leg  94  of the channel  90 . The force exerted by the spring  98  on the arm  46  (in conjunction with the top  26  contacting roller  78 ) is sufficient to pivot and reorient the engaging element  66 . 
   Advantageously, the present automatic chute opening system  12  uses a cam  76  and roller  56  arrangement to automatically open the chute  20  when the top surface  26  is opened (pivoted upwardly). The bias or spring element  98  in the system  12  is used to return the actuator  38  (the engaging element  66 ) to the chute open position, rather than to open the chute  20  (as if by the spring force). Accordingly, it is not the weight of the top surface  26  that keeps the chute  20  closed (and the top surface  26  down); rather it is the cam roller  56  residing on a straighter section  72  or slightly angled surface  74  of the engaging element  66 . 
   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.