Apparatus and method for wrapping and sealing cylindrical packages with a stretch film material

#The present invention relates to an apparatus and method for wrapping the periphery and sealing the ends of cylindrical packages with stretch film material. Such apparatus and method has particular applicability to large cylindrical package, such as rolled webs of filter material and other similar rolls of material in which it is important to not only wrap the periphery or sides, but also to seal the ends to prevent entry of moisture and dust into the package during subsequent shipment and storage.

#The only known procedures for utilizing stretch film in such a wrapping procedure which completely seals the ends would be by use of apparatus similar to that shown in the Lancaster et al U.S. Pat. No. 3,867,806 in which the periphery is first wrapped, then separate caps are applied to the ends of the package, whereupon wrapping of the side then continues which seals the end caps thereto. Further, the stretch film material which is applied to the package must be of a width greater than the length of the package in the Lancaster et al patent, as is the case in all the other prior art known to the applicants.

#In its broadest sense, the invention is directed to a system of the type described in which the package to be wrapped is supported with the longitudinal axis thereof extending horizontally and wherein the package is supported for rotation by the application of a rotary driving force against the peripheral surface thereof with the ends free of any support mechanism. The leading edge of the film material is held against the side surface of the package as the package is rotated at a predetermined rate. At rotation of the package continues the film material is maintained under tension as it is pulled from a supply or dispensing means which, in turn, is reciprocated in a horizontal path parallel to the axis of rotation of the package from a first position in which the film extends beyond one end of the package and a second position in which the film extends beyond the other end of the package. The stretching of the film will create a tendency in the film to fold inwardly over the ends. Since the film extends beyond the package a distance greater than the radius of the package the film will be caused to turn in and fold down against the ends of the package forming a seal thereagainst. The electrostatic properties of the film or "cling" will assist in causing the film to fold in and seal the ends.

#Other objects and a fuller understanding of the invention will become apparent from reading the following detailed description of a preferred embodiment, taken in conjunction with the accompanying drawings in which:

#FIG. 1 is a perspective view of the apparatus according to the present invention having a cylindrical package mounted thereon in the process of being wrapped;

#FIG. 2 is an end view of the apparatus shown in FIG. 1;

#Turning now to a discussion of the illustrated embodiment in FIGS. 1-4, it should first of all be pointed out that the apparatus 10 of the present invention is adapted for use in wrapping a cylindrical package P with a continuous length or sheet of film material F which is dispensed from a roll 40. In general, package P is supported on a pair of parallel, horizontally spaced, horizontally extending support rollers 12,14; support roller 12 being rotatably driven by a drive roller 16 and the other support roller 14 being a slave roller which rotates idly responsive to rotation of package P. The film or sheet material F is carried by a roll 40 which in turn, as illustrated in the drawings of the preferred embodiment, is mounted on a reciprocal carriage 30 and caused to reciprocate along a horizontal path parallel to the longitudinal axis of the package 10 and the support rollers 12,14. As noted hereinabove the roll 40 of film might be mounted elsewhere and delivered to a supply or dispensing means on the carriage. Carriage 30 moves between a first position where the film material F overlaps or extends beyond one end of the package a distance at least as great as the radius of the package and a second position wherein the film overlaps the other end of the package a similar distance. Film F is maintained under tension by a tension roll 44 which is caused to move in an arcuate path for increasing or decreasing the tension on the film as it is applied to the ends of the package P in relationship to the tension applied during the wrapping of the intermediate portion of package P. If the tension is increased, the overlapped portion of the stretch film material 10 is automatically caused to fold in and seal the ends of the package. If the tension is decreased, there will still be some natural folding in of the ends of the film. However, to ensure folding, a bar member 60 is preferably provided which extends across and adjacent to each end of the package P. The bar member 60 mechanically urges the film to seal as well as attracting the film toward the axis by an electrostatic buildup in the bar.

#Looking at each part in more detail, first of all there is provided a pair of side frame member 13,15 each of which includes an elongated bar 17 from which a pair of end plates 19 extend upwardly and slightly outwardly. Support roller 12 is journaled at its opposite ends to bearings on the upper edge of one set of the upwardly extending plates 19. Support roller 14 is likewise journaled into bearings at the upward edges of the similar set of plates 19 on frame member 15. A small bracket 22 is mounted on frame 15 and supports a drive motor 18 and a drive roll 16 connected to the output shaft of motor 18 and positioned in engagement with the surface of support roller 12 for the driving thereof. This is a conventional technique for causing a roll to turn and it is not believed that further elaboration is necessary. Other conventional means for driving one of the support rollers 12 are also possible, such as a motor having the output shaft thereof connected directly to the support rollers by means of some type of reducer.

#An inverted, L-shaped angle member 36 is attached to the upper inner surface of each of the frame bars 17 for providing a track-like support for carriage 30 as will be explained hereinafter. Carriage 30 includes a rectangular frame member 32 formed of a plurality of angle members welded together at the ends thereof. A roller member 34 extends outwardly from a bearing in each corner thereof and supports the carriage from opposed angle members 36 for reciprocal movement therealong beneath package P. An upstanding place 42 secured to the frame 32 at each end thereof provides support for the roll 40 of film material F. It should be recognized that roll 40 is journaled into a bearing 41 at the upper end of each plate 42.