Patent Publication Number: US-2011067364-A1

Title: Carriage For A Stretch Wrapping Machine

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Provisional Patent Application No. 61/244,573, entitled CARRIAGE FOR A STRETCH WRAPPING MACHINE, which was filed on Sep. 22, 2009, the entire contents of which are hereby incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention concerns stretch wrapping machines, and more particularly relates to a carriage for a stretch wrapping machine. 
     SUMMARY OF THE PRESENT INVENTION 
     An aspect of the present invention is to provide a stretch wrap assembly comprising a base, a turntable mounted on the base, a column extending upwardly from the base, and a carriage vertically movable upon the column, with the carriage being configured to have stretch wrap thereon for wrapping a product on the turntable. The carriage includes a first nip roller, a first pre-stretch roller, a second pre-stretch roller, a second nip roller, a third nip roller and a fourth nip roller. The carriage is configured to have stretch wrap threaded through the carriage from a roll of stretch wrap, around a portion of a circumference of the first nip roller, around a portion of a circumference of the first pre-stretch roller, around a portion of a circumference of the second pre-stretch roller, around a portion of a circumference of the fourth nip roller and to the package. The first and second nip rollers are configured to maintain the stretch wrap against the first pre-stretch roller as the stretch wrap is stretched by the first pre-stretch roller, and the third and fourth nip rollers are configured to maintain the stretch wrap against the second pre-stretch roller as the stretch wrap is stretched by the second pre-stretch roller. The first nip roller and the fourth nip roller can move rotationally and laterally relative to the first pre-stretch roller and the second pre-stretch roller, respectively. A center of rotation of the first nip roller is located on a first side of a line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller. A center of rotation of the fourth nip roller is also located on the first side of the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller. A center of rotation of the second nip roller is located on a second side of the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller. A center of rotation of the third nip roller is also located on the second side of the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller. The first and second sides are located on opposite sides to the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller. 
     Another aspect of the present invention is to provide a carriage for a stretch wrap machine comprising a housing including a first nip roller, a first pre-stretch roller, a second pre-stretch roller, a second nip roller, a third nip roller and a fourth nip roller. The carriage is configured to have stretch wrap threaded through the carriage from a roll of stretch wrap, around a portion of a circumference of the first nip roller, around a portion of a circumference of the first pre-stretch roller, around a portion of a circumference of the second pre-stretch roller, around a portion of a circumference of the fourth nip roller and to the package. The first and second nip rollers are configured to maintain the stretch wrap against the first pre-stretch roller as the stretch wrap is stretched by the first pre-stretch roller, and the third and fourth nip rollers are configured to maintain the stretch wrap against the second pre-stretch roller as the stretch wrap is stretched by the second pre-stretch roller. The first nip roller and the fourth nip roller can move rotationally and laterally relative to the first pre-stretch roller and the second pre-stretch roller, respectively. A center of rotation of the first nip roller is located on a first side of a line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller. A center of rotation of the fourth nip roller is also located on the first side of the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller. A center of rotation of the second nip roller is located on a second side of the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller. A center of rotation of the third nip roller is also located on the second side of the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller. The first and second sides are located on opposite sides to the line drawn between the center of rotation of the first pre-stretch roller and the center of rotation of the second pre-stretch roller. 
     Yet another aspect of the present invention is to provide a carriage for a stretch wrap machine comprising a housing having a base portion and a chassis movable relative to the base portion between an open position and a closed engaged position. The base portion includes a first pre-stretch roller and a second pre-stretch roller thereon. The chassis has a first nip roller, a second nip roller, a third nip roller and a fourth nip roller thereon. The housing, when in the closed engaged position, is configured to have stretch wrap threaded through the carriage from a roll of stretch wrap, around a portion of a circumference of the first nip roller, around a portion of a circumference of the first pre-stretch roller, around a portion of a circumference of the second pre-stretch roller, around a portion of a circumference of the fourth nip roller and to the package. When the housing is in the closed engaged position, the first and second nip rollers are configured to maintain the stretch wrap against the first pre-stretch roller as the stretch wrap is stretched by the first pre-stretch roller, and the third and fourth nip rollers are configured to maintain the stretch wrap against the second pre-stretch roller as the stretch wrap is stretched by the second pre-stretch roller. Centers of rotation of the first nip roller and of the second nip roller move relative to the first pre-stretch roller and centers of rotation of the third nip roller and the fourth nip roller move relative to the second pre-stretch roller, respectively, by moving the housing between the open position and the closed engaged position. 
     Another aspect of the present invention is to provide a carriage for a stretch wrap machine comprising a housing having a base portion and a chassis movable relative to the base portion between an open position and a closed engaged position. The base portion includes a first pre-stretch roller and a second pre-stretch roller thereon. The chassis has a first nip roller, a second nip roller, a third nip roller and a fourth nip roller thereon. The housing, when in the closed engaged position, is configured to have stretch wrap threaded through the carriage from a roll of stretch wrap, around a portion of a circumference of the first nip roller, around a portion of a circumference of the first pre-stretch roller, around a portion of a circumference of the second pre-stretch roller, around a portion of a circumference of the fourth nip roller and to the package. When the housing is in the closed engaged position, the first and second nip rollers are configured to maintain the stretch wrap against the first pre-stretch roller as the stretch wrap is stretched by the first pre-stretch roller, and the third and fourth nip rollers are configured to maintain the stretch wrap against the second pre-stretch roller as the stretch wrap is stretched by the second pre-stretch roller. A center of rotation of the first nip roller and a center of rotation of the second nip roller rotate about a first axis while the chassis moves between the open position and the closed engaged position. A center of rotation of the third nip roller and a center of rotation of the fourth nip roller rotate about a second axis while the chassis moves between the open position and the closed engaged position. 
     These and other aspects, objects, and features of the present invention will be understood and appreciated by those skilled in the art upon studying the following specification, claims, and appended drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a wrap machine of the present invention. 
         FIG. 2  is a schematic view of a carriage of the wrap machine of the present invention in a loaded (threaded) and ready to wrap position. 
         FIG. 3  is a schematic view of the carriage of the wrap machine of the present invention in a position between the loaded (threaded) and ready to wrap position and a loading position. 
         FIG. 4  is a top partial view of the carriage of the wrap machine of the present invention. 
         FIG. 5  is a partial front view of the carriage of the wrap machine of the present invention. 
         FIG. 6  is a partial side view of the carriage of the wrap machine of the present invention. 
         FIG. 7A  is a top view of the carriage of the wrap machine of the present invention with a top housing member and rear housing member removed for clarity. 
         FIG. 7B  is a front view of the carriage of the wrap machine of the present invention with a top housing member and rear housing member removed for clarity. 
         FIG. 7C  is a side view of the carriage of the wrap machine of the present invention with a top housing member and rear housing member removed for clarity. 
         FIG. 8A  is a top view of a chassis of the carriage of the present invention. 
         FIG. 8B  is a front view of a chassis of the carriage of the present invention. 
         FIG. 8C  is a side view of a chassis of the carriage of the present invention. 
         FIG. 9  includes front, top, bottom and side views of a door of the chassis of the carriage of the present invention. 
         FIGS. 10A and 10B  are top and side views, respectively, of first links of the chassis of the carriage of the present invention. 
         FIGS. 11A and 11B  are top and side views, respectively, of second links of the chassis of the carriage of the present invention. 
         FIG. 12  is a schematic view of a portion of the carriage of the wrap machine of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as orientated in  FIG. 1 . However, it is to be understood that the invention may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. 
     The reference number  10  ( FIG. 1 ) generally designates a wrap machine of the present invention. The wrap machine  10  includes a base  12  having a turntable  14  mounted thereon. The wrap machine  10  further includes a column  16  having a vertically movable carriage  18  (shown schematically) located thereon. Stretch wrap  20  moves with the carriage  18 . The stretch wrap  20  wraps a package  24  mounted on the turntable  14  and rotating therewith. Although not shown, the wrap machine  10  may also include a gripping and cutting device for gripping the stretch wrap  20  and cutting the stretch wrap  20  during certain portions of the process of wrapping the stretch wrap  20  about the package  24 . Such gripping and cutting devices are well known to those skilled in the art. 
     In the illustrated example, the carriage  18  ( FIG. 2 ) is used to prestretch the stretch wrap  20 .  FIG. 2  illustrates schematically prestretching components of the carriage  18  of the present invention. As illustrated in  FIG. 2 , the carriage  18  includes a source of the stretch wrap  20  in the form of a roll  22  of stretch wrap  20 , a first nip roller  25 , a first pre-stretch roller  26 , a second nip roller  27 , a second pre-stretch roller  30 , a third nip roller  32 , a fourth nip roller  33 , a dancer roller  34  and a diverter roller  35 . The stretch wrap  20  is threaded through the carriage  18  from the roll  22  of stretch wrap  20 , around a portion of the circumference of the first nip roller  25 , around a portion of the circumference of the first pre-stretch roller  26  and abutting the second nip roller  27 , around a portion of the circumference of the second pre-stretch roller  30  and abutting the third nip roller  32 , around a portion of the circumference of the fourth nip roller  33 , around a portion of the circumference of the dancer roller  34 , around a portion of the circumference of the diverter roller  35  and to the package  24 . The first pre-stretch roller  26  and the second pre-stretch roller  30  are driven (rotated) at different speeds and/or have a different circumference in order to stretch the stretch wrap  20  as it passes by the first pre-stretch roller  26  and the second pre-stretch roller  30  (as is well known to those skilled in the art). The first nip roller  25  and the second nip roller  27  are configured to maintain the stretch wrap  20  against the first pre-stretch roller  26  as the stretch wrap  20  is stretched by the first pre-stretch roller  26 . Likewise, the third nip roller  32  and the fourth nip roller  33  are configured to maintain the stretch wrap  20  against the second pre-stretch roller  30  as the stretch wrap  20  is stretched by the second pre-stretch roller  30 . Although not shown, it is contemplated that the carriage  18  could include an idler roller that rotates freely and is positioned to maintain the stretch wrap  20  against the first pre-stretch roller  26  and the second pre-stretch roller  30 . 
     The illustrated carriage  18  allows the first nip roller  25 , the second nip roller  27 , the third nip roller  32  and the fourth nip roller  33  to be spaced from the first pre-stretch roller  26  and the second pre-stretch roller  30  to allow the stretch wrap  20  to be threaded through the carriage  18 . As illustrated in  FIG. 3 , the first nip roller  25  and the second nip roller  27  are connected to each other by top and bottom first links  41  (although only the top first link  41  is illustrated in  FIGS. 2-3 ). The first links  41  pivot about a first pivot point  43 . The first links  41  are configured to be moved along line  56 . As the first pivot point  43  of the first links  41  is moved downward along line  56  as shown in  FIG. 3 , the first links  41  will rotate counter-clockwise such that the first nip roller  25  will move downward and to the left and the second nip roller  27  will move downward and to the right. Accordingly, the first nip roller  25  will be able to move past the first pre-stretch roller  26  to the position as shown in  FIG. 3 . Likewise, the third nip roller  32  and the fourth nip roller  33  are connected to each other by top and bottom second links  45  (although only the top second link  45  is illustrated in  FIGS. 2-3 ). The second links  45  pivot about a second pivot point  47 . The second links  45  are configured to be moved along line  58 . As the second pivot point  47  of the second links  45  is moved downward along line  58  as shown in  FIG. 3 , the second links  45  will rotate clockwise such that the third nip roller  32  will move downward and to the left and the fourth nip roller  33  will move downward and to the right. Accordingly, the fourth nip roller  33  will be able to move past the second pre-stretch roller  30  to the position as shown in  FIG. 3 . In this configuration, the carriage  18  will be able to be loaded with the stretch wrap  20  by threading the stretch wrap through the carriage  18  (as illustrated in  FIG. 3 ). While the illustrated embodiment only includes first links  41  and second links  45  at top and bottoms of the nip rollers, it is contemplated that only one first link  41  could be connected to a top (and not bottom) of the first nip roller  25  and the second nip roller  27  and only one second link  45  could be connected to the top (and not bottom) of the third nip roller  32  and the fourth nip roller  33 . 
     The first nip roller  25 , the second nip roller  27 , the third nip roller  32 , the fourth nip roller  33 , the first links  41  and the second links  45  are located on a chassis to allow the first nip roller  25 , the second nip roller  27 , the third nip roller  32  and the fourth nip roller  33  to be moved relative to the first pre-stretch roller  26  and the second pre-stretch roller  30 . However, it is contemplated that the first nip roller  25  and the second nip roller  27  could be located on individual chassis and the third nip roller  32  and the fourth nip roller  33  could be located on individual chassis to allow the first nip roller  25 , the second nip roller  27 , the third nip roller  32 , and the fourth nip roller  33  to be moved relative to the first pre-stretch roller  26  and the second pre-stretch roller  30 . 
     In the illustrated example, as the first pivot point  43  is moved upward along line  56  and the second pivot point  47  is moved upward along line  58 , the first nip roller  25 , the second nip roller  27 , the third nip roller  32 , the fourth nip roller  33  will return to the position in  FIG. 2  (i.e., in contact with the first pre-stretch roller  26  and the second pre-stretch roller  30 ). As the first pivot point  43  is moved upward along line  56 , the first nip roller  25  will abut the first pre-stretch roller  26 , thereby forcing the first links  41  to rotate counter-clockwise. However, once the second nip roller  27  abuts a bottom (as shown in  FIG. 2 ) of the first pre-stretch roller  26 , the first links  41  will rotate clockwise about the first pre-stretch roller  26  until both the first nip roller  25  and the second nip roller  27  abut the first pre-stretch roller  26 . Likewise, as the second pivot point  47  is moved upward along line  58 , the fourth nip roller  33  will abut the second pre-stretch roller  30 , thereby forcing the second links  45  to rotate clockwise. However, once the third nip roller  32  abuts a bottom (as shown in  FIG. 2 ) of the second pre-stretch roller  30 , the second links  45  will rotate counter-clockwise about the second pre-stretch roller  30  until both the third nip roller  32  and the fourth nip roller  33  abut the second pre-stretch roller  30 . 
       FIGS. 4-6  illustrate an embodiment of the carriage  18  of the present invention. The carriage  18  includes a base housing  60  configured to ride on the column  16  as is well known to those skilled in the art. In the illustrated example, the base housing  60  includes a rear wall  66  having a vertical travel attachment assembly  68  configured to be located on a support within the column  16  to allow the carriage  18  to move vertically on the column  16 . The base housing  60  also includes a bottom housing member  70  and a top housing member  72  connected to the rear wall  66 . The first pre-stretch roller  26  and the second pre-stretch roller  30  are each connected to an axle  73  (see  FIG. 5 ) extending between the top housing member  72  and the bottom housing member  70 . The top housing member  72  and/or the bottom housing member  70  can include components for controlling the rotation of the first pre-stretch roller  26  and the second pre-stretch roller  30  to control the prestretching of the stretch wrap  20  as is well known to those skilled in the art. The bottom housing member  70  also includes a pivot pin (not shown) for pivotally connecting a chassis  64  to the base housing  60 . The bottom housing member  70  can also include a pivot stop  71  for limiting pivotal movement of the chassis  64 . The base housing  60  has a mandrel  62  for receiving the roll  22  of stretch wrap  20 . The base housing  60  also includes the first pre-stretch roller  26 , the second pre-stretch roller  30  and the dancer roller  34 . The first nip roller  25 , the second nip roller  27 , the third nip roller  32  and the fourth nip roller  33  are connected to a chassis or door  64  (see  FIGS. 8A and 8B ) movable relative to the base housing  60  by extending a pivot pin (not shown) through openings  61  in pivot blocks  63  extending from a bottom of the chassis  64  to allow the chassis  64  to pivot along line  65  as illustrated in  FIG. 6 . In the illustrated example, the chassis  64  is pivotally connected to the base housing  60 . However, it is contemplated that the chassis  64  could be slidably connected to the base housing  60  (e.g., using drawer slides) or have a vertical (instead of a horizontal) hinge. 
     As illustrated in  FIGS. 5-8C , the chassis  64  is pivotally connected to a front of the bottom housing member  70  of the base housing  60  to allow the chassis  64  to be rotated along line  65  (see  FIG. 6 ) relative to the base housing  60 . The chassis  64  comprises a U-shaped door  74  having a top portion  76 , a bottom portion  78  and a front face portion  80  extending between the top portion  76  and the bottom portion  78 . The U-shaped door  74  also includes a first nip roller assembly  82  comprising the first nip roller  25 , the second nip roller  27 , the first links  41  and axles extending through the first nip roller  25  and the second nip roller  27  and connected to the first links  41  (to allow the first nip roller  25  and the second nip roller  27  to rotate). The U-shaped door  74  also includes a second nip roller assembly  84  comprising the third nip roller  32 , the fourth nip roller  33 , the second links  45  and axles extending through the third nip roller  32  and the fourth nip roller  33  and connected to the second links  45  (to allow the third nip roller  32  and the fourth nip roller  33  to rotate). 
     In the illustrated example, during use of the wrap machine  10  to wrap the package  24  with stretch wrap  20 , the chassis  64  will be locked into position relative to the base housing  60  as illustrated in  FIGS. 5-7C  (and as shown schematically in  FIG. 2 ). Furthermore, the first nip roller  25  and the second nip roller  27  will be locked into position abutting the first pre-stretch roller  26  and the third nip roller  32  and the fourth nip roller  33  will be locked into position abutting the second pre-stretch roller  30 . Once the roll  22  of stretch wrap  20  is empty and the carriage  18  must be refilled with another roll  22  of stretch wrap  20 , the chassis  64  must be moved to allow access to the stretch wrap  20  to be loaded (threaded) as discussed above in regard to  FIG. 3 . 
     Once the first nip roller  25  and the second nip roller  27  are moved outward as described above, the chassis  64  can be rotated about a pivot point along line  65  to allow the carriage to be loaded (threaded) as also described above in regard to  FIG. 3 . In order to position the chassis  64  back into position for wrapping the product  24 , the chassis  64  is once again rotated about a pivot point until the chassis  64  is positioned upright again. It is contemplated that a top spring and/or a bottom spring can be connected to tops and bottoms of the first nip roller assembly and the second nip roller assembly to bias the first nip roller assembly and the second nip roller assembly to their base position (e.g., forcing the first links  41  in a clockwise direction and forcing the second links  45  in a counter-clockwise direction). It is also contemplated that a top spring and/or a bottom spring can be connected to tops and bottoms of the first nip roller assembly and the second nip roller assembly to bias the first nip roller assembly and the second nip roller assembly to their open position (e.g., forcing the first links  41  in a counter-clockwise direction and forcing the second links  45  in a clockwise direction). 
     In the illustrated embodiment, it is noted that when the first nip roller  25  and the fourth nip roller  33  contact the first pre-stretch roller  26  and the second pre-stretch roller  30 , respectively, the point of contact is beyond the front face of the circumference of the first pre-stretch roller  26  and the second pre-stretch roller  30  as viewed from  FIG. 7A  (i.e., on side A of lines  200  and  202  as illustrated in  FIG. 12 ). It is contemplated that the chassis  64  could be locked in position. 
     The above description is considered that of the one embodiment only. Modification of the invention will occur to those skilled in the art and to those who make or use the invention. For example, it is contemplated that the carriage  18  could include a pivoting arm  300  holding the dancer roller  34 , with the arm  300  being biased by a spring  302  for keeping the dancer roller  34  taut against the stretch wrap  20  (see  FIG. 7A ). Moreover, it is contemplated that the second nip roller  27  could have a spacing  101  (see  FIG. 7B ) to allow the second nip roller  27  to clear any obstacles is it is rotated between the loading and loaded positions. Furthermore, it is contemplated that the carriage could be used in an overhead wrapping apparatus as is well known to those skilled in the art. Further, it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise.