Patent Publication Number: US-5628167-A

Title: Method and apparatus for wrapping elongate load having generally circular or generally annular ends

Description:
TECHNICAL FIELD OF THE INVENTION 
     This invention pertains to a method and apparatus for wrapping an elongate load having generally circular or generally annular ends, such as a textile roll having a tubular core, with a Wrapping film, such as a stretch film. In a preferred mode, which is useful particularly with an elongate load having generally annular ends, a central portion of each end of the load remains unwrapped. 
     BACKGROUND OF THE INVENTION 
     Commonly, an elongate load having generally annular ends, such as a textile roll having a tubular core, is wrapped with a wrapping film, such as a shrink or stretch film, in a full web pattern as the elongate load is positioned axially within a film delivery system. The wrapping film is gathered at the opposite ends of the wrapped load, and the gathered film is clamped, welded to itself, or tied. 
     Therefore, if it is desired to insert a lift arm of a lift truck into a selected end of the wrapped load, it is necessary to break through the wrapping film at the selected end. Breaking through the wrapping film can leave ragged edges by means of which the wrapping film may begin to unwrap from the wrapped load, and whereby, in addition, the wrapped load may be exposed to soiling or damage. 
     SUMMARY OF THE INVENTION 
     This invention provides a method and apparatus for wrapping a wrapping film, supplied from a roll defining a roll axis over an elongate load, which has a generally cylindrical exterior defining a load axis and which has two generally circular or generally annular ends. In a preferred mode, which is useful particularly with an elongate load having generally annular ends, the method permits a central portion of each end of the load to remain unwrapped. 
     Broadly, the method comprises the steps of cradling the load with the load axis extending horizontally, mounting the roll of film with the roll axis extending vertically, and moving the mounted roll around successive halves of a circular path and back and forth along the load so that the roll is moved along an oblong path with a straight section along each side of the load and with a half-circular section around each end of the load, as the cradled load is rotated about the load axis, so as to wrap the near side of the load, one end of the load, the far side of the load, and the other end of the load with the wrapping film pulled from the roll. 
     Preferably, the load is cradled so as to be rotatable about the load axis, and the method further comprises rotating the cradled load about the load axis as the roll is moved along the oblong path, the roll remaining at an elevation above a central portion of each end of the load so as to permit the central portion to remain unwrapped. 
     Preferably, the moving and rotating steps are performed by moving the roll in one direction along the load while the load is being rotated, moving the roll across one end of the load while the load is not being rotated, moving the roll oppositely along the load while the load is being rotated, and moving the roll across the other end of the load while the load is not being rotated. 
     In the apparatus provided by this invention, means are provided for cradling the load with the load axis extending horizontally so as to define a near side of the load and a far side of the load, and so as to permit the load to be rotated about the load axis, for mounting the roll film with the roll axis extending vertically and for moving the mounted roll around successive halves of a cylindrical path and back and forth along the load so that the roll is moved along an oblong path with a straight section along each side of the load and with a half-circular section around each end of the load, as the cradled load is rotated about the load axis, so as to wrap the near side of the load, one end of the load, the far side of the load, and the other end of the load with the wrapping film pulled from the roll. 
     Preferably, the apparatus further comprises means for rotating the cradled load about the load axis as the roll is moved along the oblong path, the roll remaining at an elevation above a central portion of each end of the load so as to permit the central portion to remain unwrapped. 
     Preferably, moreover, the mounting and moving means include a track extending horizontally, a carriage movable along the track, and an arm having a distal end and a proximal end, the roll being mounted upon the distal end and the proximal end being rotatably mounted upon the carriage so that the arm is rotatable about a vertical axis at the proximal end. 
     Preferably, furthermore, the mounting and moving means and the rotating means are operable for moving the carriage so as to move the roll of film in one direction along the load while the arm is not being rotated but while the load is being rotated, rotating the arm so as to move the roll of film in an arc across one end of the load while the load is not being rotated, moving the carriage so as to move the roll of film oppositely along the load while the arm is not being rotated but while the load is being rotated, and rotating the arm so as to move the roll of film in an arc across the other end of the load while the load is not being rotated. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects, features, and advantages of this invention will be evident from the following description of a preferred embodiment of this invention when reference is made to the accompanying drawings in which like reference characters designate like or corresponding parts throughout the several view and wherein: 
     FIG. 1 is a simplified, perspective view of a wrapping apparatus constituting a preferred embodiment of this invention, as used for wrapping an elongate load having generally annular ends, with a wrapping film, such as a stretch film. 
     FIG. 2 is an end view of the wrapping apparatus, the elongate load, and the stretch film, as shown in FIG. 1. 
     FIG. 3 is a plan view of the wrapping apparatus, the elongate load, and the stretch film, as shown in FIG. 1. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in the drawings, an apparatus 10 constituting a preferred embodiment of this invention can be advantageously employed for wrapping an elongate load 12, having a generally cylindrical exterior 14, a tubular core 16, and generally annular ends 18, with a stretch film 20 from a roll 22, in a manner described below, so as to permit a central portion 24 of the tubular core 16 at each end 18 of the load 12 to remain unwrapped. Therefore, if it is desired to insert a lift arm (not shown) of a lift truck into the central portion 24 of the tubular core 16 at a selected end 18 of the wrapped load 12, it is not necessary to break through the stretch film 20 at the selected end. 
     As examples, which are not intended as limiting, the load 12 may be a textile, carpeting, or paper roll, in which the tubular core 16 is a wound paper core. The load 12 defines a load axis A L  and the roll 22 of the stretch film 20 defines a roll axis A R . 
     The apparatus 10 comprises means 30 including a pair of blocker rolls 32, which are rotatably mounted upon a support 34 so as to extend horizontally in side-by-side relation with respect to each other, for cradling the load 12 with the load axis A L  extending horizontally so as to define a near side of the load 12 and a far side of the load 12, and so as to permit the load 12 to be rotated about the load axis A L . The cradling means 30 further includes a motor M L , which is shown diagrammatically, and which is arranged to rotate one of the blocker rolls 32 so as to rotate the cradled load 12 about the load axis A L . 
     The apparatus 10 further comprises means 40 including a dispenser 42 for mounting the roll of film 22 with the roll axis A R  extending vertically so as to permit the film 20 to be pulled horizontally from the roll 22. The dispenser 42 is mounted so as to be selectively positionable along a vertical shaft 44, which is suspended from a rotatable arm 50. The dispenser 42 is positioned along the vertical shaft 44 so as to position the roll 22 at an elevation above the tubular core 16 at each end 18 of the load 12. The vertical shaft 44 mounts a lower stop 46, which limits positioning of the dispenser 42 in a downward direction. The rotatable arm 50 limits positioning of the dispenser 42 in an upward direction. The rotatable arm 50 has a distal end 52, from which the vertical shaft 44 is suspended, and a proximal end 54. 
     The apparatus 10 further comprises means 60 including a carriage 62, below and to which the arm 50 is rotatably mounted at the proximal end 54, and a motor M A , which is arranged to rotate the arm 50 relative to the carriage 62. The carriage 62 has wheels 70, which enable the carriage 62 to move back and forth along a track 64 extending horizontally and supported on upright columns 66 with lower stabilizing legs 68, and is arranged for moving the mounting means 40 (which includes the dispenser 42, the vertical shaft 44 and the rotatable arm 50) and the mounted roll 22 back and forth along the near side of the cradled load 12. The carrying means 60 further includes a motor M C , which is arranged to move the carriage 62, the mounting means 40, and the mounted roll 22 back and forth along the track 64, and the motor M A , which is arranged for rotating the rotatable arm 50 about the vertical axis through the proximal end 54. 
     The motor M L  for rotating the cradled load 12, the motor M A  for rotating the arm 50 relative to the carriage 12, and the motor M C  for moving the carriage 62 back and forth along the track 64 are cyclicly controlled by means of a programmable controller C P  or a computer (not shown) so that the carriage 62 is moved by means of the motor M L  in a first direction along the track 64 so as to move the roll 22 in the first direction along the near side of the cradled load 12 while the arm 50 is not being rotated but while the cradled load 12 is being rotated by means of the motor M L , so that the arm 50 is rotated by means of the motor M A  over a first half of one revolution so as to move the cradled roll 22 in an arc across a first end 18 of the load 12 while the cradled load 12 is not being rotated, so that the carriage 62 is moved by means of the motor M C  in a second (opposite) direction along the track 64 so as to move the roll 22 in the second direction along the far side of the cradled load 12 while the arm 50 is not being rotated but while the cradled load 12 is being rotated by means of the motor M L , and so that the arm 50 is rotated by means of the motor M A  over the second (opposite) half of one revolution so as to move the roll 22 in an arc across the second (opposite) end 18 of the cradled load 12 while the cradled load 12 is not being rotated. The carriage 62 may or may not be moving when the roll 22 is moved in an arc in either direction. 
     Consequently, the roll 22 is moved along an oblong path with a straight section along each side of the cradled load 12 and with a half-circular section around each end 18 of the cradled load 12, as the cradled load 12 is rotated about the load axis A L , so as to wrap the near side of the cradled load 12, one end 18 of the cradled load 12, the far side of the cradled load 12, and the other end 18 of the cradled load 12, with the stretch film 20 pulled from the roll 22. 
     As shown in FIG. 1, a conveyor 80 employing an endless belt 82 is employed to deliver successive loads 12, which are transferred manually or otherwise onto the blocker rolls 32 of the cradling means 30 of the apparatus 10. The conveyor 80 is also employed to remove each load 12 after such load 12 has been wrapped. 
     After an initial length of the stretch film 20 has been manually pulled from the roll 22, a free end of the initial length is taped or otherwise secured to the cradled load 12, whereupon the apparatus 10 is operated. Because the cradled load 12 is rotated about the load axis A L  as the stretch film 20 is pulled from the roll 22 onto the cradled load 12, the stretch film 20 tends to contact the cradled load 12 or previously wrapped layers of the stretch film 20 between the opposite edges of the stretch film 20 and to be spirally wrapped around the cradled load 12, at a slight inclination relative to the load axis A L  along each side of the cradled load 12. 
     Because the roll 22 remains at an elevation above the tubular core 16 at each end 18 of the load 12, the tubular core 16 remains unwrapped at each end 18 of the cradled load 12. In multiple cycles of the apparatus 10, the cradled load 12 can be completely wrapped with the stretch film 20 pulled from the roll 22, except that the tubular core 16 remains unwrapped at each end 18 of the cradled load 12. 
     Various modifications may be made in the preferred embodiment described above without departing from the scope and spirit of this invention. It is therefore to be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.