Patent Publication Number: US-7908830-B2

Title: Carriage for a stretch wrapping machine

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Provisional Patent Application No. 60/979,623 filed on Oct. 12, 2007 entitled CARRIAGE FOR A STRETCH WRAPPING MACHINE. 
    
    
     FIELD OF THE INVENTION 
     The present invention concerns stretch wrapping machines, and more particularly relates to a carriage for a stretch wrapping machine. 
    
    
     
       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 schematic view of the carriage of the wrap machine of the present invention in the loading position. 
         FIG. 5  is a front view of the carriage of the wrap machine of the present invention. 
         FIG. 6  is a side view of the carriage of the wrap machine of the present invention. 
         FIG. 7  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. 8  is an isometric view of a chassis of the carriage of the present invention. 
         FIG. 8A  is a side view of a nip roller assembly of the chassis of the carriage of the present invention. 
         FIG. 9  is a top schematic view of a portion of the chassis of the carriage of the present invention showing movement of the nip roller assemblies of the chassis of the carriage of the present invention. 
         FIG. 10  is a front schematic view of a handle  100  and a linking assembly for moving the nip roller assemblies of the chassis of the carriage of the present invention. 
         FIG. 11  is a schematic view of a portion of the carriage of the wrap machine of the present invention. 
     
    
    
     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, an idler roller, a second pre-stretch roller and a second 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 idler roller, around a portion of a circumference of the second pre-stretch roller, around a portion of a circumference of the second nip roller and to the package. The idler roller rotates freely and is positioned to maintain the stretch wrap against the first pre-stretch roller and the second pre-stretch roller. The first nip roller is configured to maintain the stretch wrap against the first pre-stretch roller as the stretch wrap is stretched by the first pre-stretch roller. The second nip roller is 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 second nip roller can move rotationally and laterally relative to the first pre-stretch roller and the second pre-stretch roller, respectively. The idler roller is spaced from the first pre-stretch roller such that the idler roller and the first pre-stretch roller do not touch. The idler roller is spaced from the second pre-stretch roller such that the idler roller and the second pre-stretch roller do not touch. A center of rotation of the idler roller is located on a first side of a line drawn between a center of rotation of the first pre-stretch roller and a center of rotation of the second pre-stretch roller. A center of rotation of first 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 second 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. 
     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, an idler roller, a second pre-stretch roller and a second 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 idler roller, around a portion of a circumference of the second pre-stretch roller, around a portion of a circumference of the second nip roller and to the package. The idler roller rotates freely and is positioned to maintain the stretch wrap against the first pre-stretch roller and the second pre-stretch roller. The first nip roller is configured to maintain the stretch wrap against the first pre-stretch roller as the stretch wrap is stretched by the first pre-stretch roller. The second nip roller is 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 second nip roller can move rotationally and laterally relative to the first pre-stretch roller and the second pre-stretch roller, respectively. The idler roller is spaced from the first pre-stretch roller such that the idler roller and the first pre-stretch roller do not touch. The idler roller is spaced from the second pre-stretch roller such that the idler roller and the second pre-stretch roller do not touch. A center of rotation of the idler roller is located on a first side of a line drawn between a center of rotation of the first pre-stretch roller and a center of rotation of the second pre-stretch roller. A center of rotation of the first 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 second 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. 
     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, an idler roller and a second 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 idler roller, around a portion of a circumference of the second pre-stretch roller, around a portion of a circumference of the second nip roller and to the package. When the housing is in the closed engaged position, the idler roller rotates freely and is positioned to maintain the stretch wrap against the first pre-stretch roller and the second pre-stretch roller, the first nip roller is 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 second nip roller is 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 second nip roller can move laterally relative to the first pre-stretch roller and the second pre-stretch roller, respectively, by moving the housing between the open position and the closed engaged position. The idler roller is spaced from the first pre-stretch roller such that the idler roller and the first pre-stretch roller do not touch when the housing is in the engaged position. The idler roller is spaced from the second pre-stretch roller such that the idler roller and the second pre-stretch roller do not touch when the housing is in the engaged position. 
     A further 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, an idler roller and a second 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 idler roller, around a portion of a circumference of the second pre-stretch roller, around a portion of a circumference of the second nip roller and to the package. When the housing is in the closed engaged position, the idler roller rotates freely and is positioned to maintain the stretch wrap against the first pre-stretch roller and the second pre-stretch roller, the first nip roller is 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 second nip roller is configured to maintain the stretch wrap against the second pre-stretch roller as the stretch wrap is stretched by the second pre-stretch roller. In the open position, the idler roller is not directly located between the first pre-stretch roller and the second pre-stretch roller. In the closed engaged position, the idler roller is directly located between the first pre-stretch roller and the second pre-stretch roller. The idler roller moves along a first plane as the housing moves from the open position to the closed engaged position. The first nip roller and the second nip roller firstly move along a second plane and a third plane, respectively, as the housing moves from the open position to the closed engaged position and then secondly moves along a first arc and a second arc as the housing moves from the open position to the closed engaged position. The first plane, the second plane and the third plane are parallel. 
     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. 
     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. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting. 
     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 , an idler roller  28 , a second pre-stretch roller  30 , a second nip roller  32  and a dancer roller  34 . 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 , around a portion of the circumference of the idler roller  28 , around a portion of the circumference of the second pre-stretch roller  30 , around a portion of the circumference of the second nip roller  32 , around a portion of the circumference of the a dancer roller  34 , 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 idler roller  28  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 first nip roller  25  is 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 second nip roller  32  is 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 . 
     The illustrated carriage  18  allows the first nip roller  25 , the second nip roller  32  and the idler roller  28  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  is configured to be moved away from the first pre-stretch roller  26  along line  56  (which can be straight or angled). Likewise, the second nip roller  32  is configured to be moved away from the second pre-stretch roller  30  along line  58  (which can be straight or angled). As described below, the first nip roller  25 , the second nip roller  32  and the idler roller  28  are located on a chassis to allow the first nip roller  25 , the second nip roller  32  and the idler roller  28  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 , the second nip roller  32  and the idler roller  28  could each be located on individual chassis (or two of these on a single chassis and one of these on a single chassis) to allow the first nip roller  25 , the second nip roller  32  and the idler roller  28  to be moved relative to the first pre-stretch roller  26  and the second pre-stretch roller  30 . 
       FIG. 4  illustrates one manner of moving the first nip roller  25 , the second nip roller  32  and the idler roller  28  relative to the first pre-stretch roller  26  and the second pre-stretch roller  30 . As illustrated in  FIG. 4 , the first nip roller  25  can move along line  40 , the second nip roller  32  can move along line  44  and the idler roller  28  can move along line  42 . Thereafter, the stretch wrap  20  can easily be routed or threaded along a bottom  46  of the first pre-stretch roller  26  and a bottom  48  of the second pre-stretch roller  30  to the dancer roller  34  as illustrated in  FIG. 4 . Then, the first nip roller  25  can move along line  50  (opposite to line  40 ), the second nip roller  32  can move along line  54  (opposite to line  44 ) and the idler roller  28  can move along line  52  (opposite to line  42 ). Finally, as illustrated in  FIG. 3 , the first nip roller can move back to its base position along line  36  (opposite to line  56 ) and the second nip roller  32  can move back to its base position along line  38  (opposite to line  58 ), to finish in the position shown in  FIG. 2 . 
       FIGS. 5 and 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 .  FIG. 7  illustrates the carriage  18  without the top housing member  72  and the rear wall  66  for a better understanding of the embodiment of the present invention. As illustrated in  FIGS. 5-7 , the first pre-stretch roller  26  and the second pre-stretch roller  30  are each connected to an axle  73  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  32  and the idler roller  28  are connected to a chassis or door  64  (see  FIG. 8 ) 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). 
     As illustrated in  FIGS. 5-8 , 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 idler roller  28  is located on an axle  75  extending between the top portion  76  and the bottom portion  78  of the U-shaped door  74 . The U-shaped door  74  also includes a first nip roller assembly  82  having the first nip roller  25  and a second nip roller assembly  84  having the second nip roller  32  connected thereto. 
       FIG. 8A  illustrates the first nip roller assembly  82 , with the second nip roller assembly  84  being substantially similar to the first nip roller assembly  82  (except for possible dimension changes). In the illustrated example, the first nip roller assembly  82  comprises a first nip roller pivot axle  86  extending between the top portion  76  and the bottom portion  78  of the U-shaped door  74  at a first side thereof (adjacent the roll  22  of stretch wrap  20 ), a top nip roller pivot link  88  fixedly connected to a top of the first nip roller pivot axle  86  and a bottom nip roller pivot link  89  fixedly connected to a bottom of the first nip roller pivot axle  86 . The first nip roller  25  is connected to the top nip roller pivot link  88  at a top thereof and to the bottom roller pivot link  89  at a bottom thereof. The first nip roller  25  is allowed to freely rotate relative to the top nip roller pivot link  88  and to the bottom roller pivot link  89 . As discussed in more detail below, the first nip roller assembly  82  is configured to interact with a handle  100  to move the first nip roller  25  along the lines  36  and  56 . 
     The illustrated second nip roller assembly  84  comprises a second nip roller pivot axle  92  extending between the top portion  76  and the bottom portion  78  of the U-shaped door  74  at a second side thereof (adjacent a diverter roller  35 ), a top nip roller pivot link  94  fixedly connected to a top of the second nip roller pivot axle  92  and a bottom nip roller pivot link  96  fixedly connected to a bottom of the second nip roller pivot axle  92 . The second nip roller  32  is connected to the top nip roller pivot link  94  at a top thereof and to the bottom roller pivot link  96  at a bottom thereof. The second nip roller  32  is allowed to freely rotate relative to the top nip roller pivot link  94  and to the bottom roller pivot link  96 . As discussed in more detail below, the second nip roller assembly  84  is configured to interact with the handle  100  to move the second nip roller  32  along the lines  38  and  58 . 
     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. 5-7  (and as shown schematically in  FIG. 2 ). Furthermore, the first nip roller  25  will be locked into position abutting the first pre-stretch roller  26  and the second nip roller  32  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. 4 . The first step in moving the chassis  64  to the loading position is to move the first nip roller  25  away from the first pre-stretch roller  26  along line  56  and to move the second nip roller  32  away from the second pre-stretch roller  30  along line  58 . 
     The illustrated handle  100  (see  FIGS. 5-8 ) is employed to move the first nip roller  25  away from the first pre-stretch roller  26  along line  56  and to move the second nip roller  32  away from the second pre-stretch roller  30  along line  58 . The handle  100  is connected to a linking assembly  102  (see  FIG. 9 ), which in turn is connected to the first nip roller assembly  82  and the second nip roller assembly  84 . The linking assembly  102  includes a first link member  104  connected to the first nip roller pivot axle  86  and a second link member  106  connected to the second nip roller pivot axle  92 . As illustrated in  FIGS. 7 and 8 , the handle  100  is pivotable about an axis that is perpendicular to a front face of the front face portion  80  of the U-shaped door  74 . The handle  100  extends through the front face portion  80  of the U-shaped door  74  and includes a hub  110  connected to the first link member  104  and the second link member  106 . The first link member  104  and the second link member  106  are configured to move linearly along lines  112  and  114  as shown in  FIGS. 9 and 10 . The first link member  104  is connected to the hub  110  above the center of rotation of the hub  110  and the second link member  106  is connected to the hub  110  below the center of rotation of the hub  110 . Therefore, rotation of the handle  100  in the clockwise direction (as shown along line  111  in  FIG. 10 ) will force the hub  110  to pull the first link member  104  to the right as shown in  FIGS. 9 and 10  (i.e., towards the handle  100 ) and to pull the second link member  106  to the left as shown in  FIGS. 9 and 10  (i.e., towards the handle  100 ). 
     As illustrated in  FIG. 9 , the first nip roller pivot axle  86  of the first nip roller assembly  82  includes a flange  120  extending therefrom. The flange  120  is pivotally connected to the first link member  104  at pivot point  122 . Likewise, the second nip roller pivot axle  92  of the second nip roller assembly  84  includes a flange  124  extending therefrom. The flange  124  is pivotally connected to the second link member  106  at pivot point  126 . As the first link member  104  is pulled towards the center during rotation of the handle  100  in the clockwise manner as discussed above, the flange  120  will be pulled to the right in  FIGS. 9 and 10 , thereby forcing the first nip roller pivot axle  86  to rotate in a counter-clockwise direction. Likewise, as the second link member  106  is pulled towards the center during rotation of the handle  100  in the clockwise manner as discussed above, the flange  124  will be pulled to the left in  FIGS. 9 and 10 , thereby forcing the second nip roller pivot axle  92  to rotate in a clockwise direction. 
     As illustrated in  FIG. 9 , as the first nip roller pivot axle  86  rotates in the counter-clockwise direction, the top nip roller pivot link  88  connected to a top of the first nip roller pivot axle  86  and the bottom nip roller pivot link  89  connected to a bottom the first nip roller pivot axle  86  will force the first nip roller  25  to move along line  56  (from  25  and  88  to  25 ′ and  88 ′ in  FIG. 9  (i.e., in the configuration illustrated schematically in  FIG. 3 )). Likewise, as the second nip roller pivot axle  92  rotates in the clockwise direction, the top nip roller pivot link  94  connected to a top of the second nip roller pivot axle  92  and the bottom nip roller pivot link  96  connected to a bottom of the second nip roller pivot axle  92  will force the second nip roller  32  to move along line  58  (from  32  and  94  to  32 ′ and  94 ′ in  FIG. 9  (i.e., in the configuration illustrated schematically in  FIG. 3 )). 
     Once the first nip roller  25  and the second nip roller  32  are moved outward as described above, the chassis  64  can be rotated about pivot point  69  along line  65  to allow the carriage to be loaded (threaded) as also described above in regard to  FIG. 4 . In order to position the chassis  64  back into position for wrapping the product  24 , the chassis  64  is once again rotated about pivot point  69  along line  83  until the chassis  64  is positioned upright again. The handle  100  can then be rotated in a counter clockwise direction, thereby forcing the first nip roller  25  and the second nip roller  32  into contact with the first pre-stretch roller  26  and the second pre-stretch roller  30 , respectively, in a manner opposite to that described above. It is contemplated that a top spring and/or a bottom spring can be connected to tops and bottoms of the first nip roller pivot axle  86  and the second nip roller pivot axle  92  to bias the first nip roller pivot axle  86  and the second nip roller pivot axle  92  to their base position (i.e., forcing the first nip roller  25  and the second nip roller  32  into contact with the first pre-stretch roller  26  and the second pre-stretch roller  30 , respectively). 
     In the illustrated embodiment, it is noted that when the first nip roller  25  and the second nip roller  32  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. 7  (i.e., on side A of lines  200  and  202  as illustrated in  FIG. 11 ). Furthermore, once the first nip roller  25  and the second nip roller  32  are forced into contact with the first pre-stretch roller  26  and the second pre-stretch roller  30 , respectively, the chassis  64  will not be able to be rotated (as the first pre-stretch roller  26  and the second pre-stretch roller  30  will prevent movement of the first nip roller  25  and the second nip roller  32  and thereby movement of the chassis  64 ). It is contemplated that the chassis  64  could be locked in position. For example, the handle  100  can be locked into position, thereby maintaining the position of the first nip roller  25  and the second nip roller  32  in contact with the first pre-stretch roller  26  and the second pre-stretch roller  30 , respectively. It is contemplated that the handle  100  could include a lip on a terminal end thereof having an opening that is configured to be aligned with an opening on a latch flange such that an item (e.g., a padlock) can be placed through the aligned openings to lock the handle in position, thereby maintaining the position of the first nip roller  25  and the second nip roller  32  in contact with the first pre-stretch roller  26  and the second pre-stretch roller  30 , respectively. 
     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 arms holding the nip rollers could be locked into place in some manner (e.g., a retractable pin) to lock the nip rollers in place and that the arms holding the nip rollers could be moved in any manner. It is further 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. 7 ). 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. Therefore, it is understood that the embodiment shown in the drawings and described above is merely for illustrative purposes and not intended to limit the scope of the invention.