Patent Grant
4945707
1. Field of the Invention The invention relates to a machine and method for overwrapping cylindrical or nearly cylindrical articles for packaging or labeling of those articles. More particularly, the invention relates to a machine and method for shrink-wrapping individual rolls of adhesive tape rolls. 2. Description of the Prior Art Machines are known for wrapping articles and, in particular, cylindrical or nearly cylindrical articles. One such commercial machine is disclosed in U.S. Pat. No. 3,659,394. The machine is specifically designed and used for packaging and labeling articles, such as adhesive tape rolls. These adhesive tape rolls vary in size, but they typically are manufactured in widths of between 1/4 inch up to 2 to 3 inches. The rolls are individually wrapped in a two-step process. In the first stage, a wrapping machine, such as that disclosed in the above patent, is used to individually wrap the adhesive tape rolls. This is accomplished by feeding the sheet of wrapping material (e.g., a shrink wrappable material such as PVC film) in the form of a web from a supply reel, applying an adhesive to the leading edge thereof, setting the roll on the leading edge of the web, and then causing the roll to rotate in engagement with the sheet material to thereby entrain the material, thus automatically wrapping the same around its own external periphery. This operation is normally accomplished with a row of spaced-apart rolls being fed and wrapped simultaneously as they move along a conveyor. In the second step, the successive rows of the individually-wrapped rolls are then discharged from the machine and transferred to a second conveyor of a heating tunnel wherein the rolls are fed into an oven and subjected to heat to cause the sheet material to shrink-wrap around the peripheral edge of the cylindrical rolls of tape. The articles are then discharged from the heating oven for packaging and shipment to the customer. One of the problems with this commercial technique is that the speed of the unit is limited due to the employment of a clutch brake system for actuation of the conveyor which transports the cylindrical rolls of tape. Due to the abrupt start and stop movement of a conveyor with such a mechanism, the cylindrical rolls of tape which are free standing on the conveyor are often jossled, causing toppling of the rolls. This, in turn, requires that the machine be stopped or slowed down to remove the fallen rolls of tape. Another problem caused by this two-step process is that one must use adhesive or glue to temporarily adhere the leading and trailing edges of the film and prevent the unwrapping of the rolls when moved from the conveyor of the wrapping unit to the conveyor of the heat tunnel. The machines, as well, are relatively bulky and complicated in design, often requiring long shut-downs periods due to cumbersome and time-consuming repair and maintenance requirements. Accordingly, it is an object of the present invention to provide an improved machine for overwrapping cylindrical and nearly cylindrical articles, whether as individual articles per package or as multiple articles per package, or whether individual packages per machine cycle or multiple packages per machine cycle. It is also an object of the present invention to provide such a machine which is relatively simple in design, has a high degree of reliability and flexibility and provides significantly higher speeds of operation. It is a more particular object of the present invention to eliminate the need for the use of glue for causing the sheet material to adhere to the cylindrical objects and to eliminate the need to use pre-slit rolls of wrapping material. It is a further object of the present invention to provide a machine having the foregoing attributes and characteristics which provide for a smooth acceleration and deceleration of the conveyor to minimize jossling of the articles to be packaged. Certain of the foregoing and related objects are readily attained in a machine for wrapping generally cylindrical articles enbodying the present invention which includes a supply reel rotatably mounted in the machine for unreeling a web of sheet material, an endless transport means including a multiplicity of spaced-apart rollers operatively mounted thereon for moving the articles along a predetermined path, means for guiding and feeding the web on to said rollers of the endless transport means operatively connected to said supply reel, and means for feeding articles at predetermined intervals on to said web at a location at which it has already been guided on to said transport means, the movement of such feeding being synchronized to the movement of the transport means. The machine also includes transverse cutting means operatively coacting with the transport means for severing a predetermined portion of the web after an article has been placed thereon, and abutment means operatively mounted along the predetermined path disposed to tangentially engage the rollers of the transport means causing their rotation which, in turn, causes rotation of the articles in a direction opposite the movement of the transport means, thereby wrapping a predetermined portion of the web around themselves. The machines especially include means for exposing the wrapped articles to heat for the purpose of hot sealing, shrinking or drying the sheet material and securely wrapping it about the articles, disposed along a portion of the endless transport means, and electronically-controlled drive means for accelerating and decelerating the transport means in timed relation with respect to the movement of said web and the feeding of the articles. Preferably the machine additionally including spray means for applying a liquid spray (especially water) to the web. In addition, the means for exposing advantageously comprises a heat tunnel having a generally inverted U-shaped housing which defines a tunnel extending along a portion of the predetermined path, means for heating the air in the tunnel and means for circulating heated air through the tunnel. Most desirably, the housing is double-walled so as to define an outer shell and inner shell and an air gap therebetween. In a particularly preferred embodiment of the invention, the electronically-controlled drive means comprises an electric stepping motor operatively coupled to the transport conveyor and an electronic motor controller coupled to the stepping motor for controlling the speed of operation and the acceleration and deceleration of the stepping motor. Most advantageously, the electronically-controlled drive means includes a programmable electronic sequence controller for electronically sequencing the transport conveyor drive means in timed sequence to the means for feeding the web and the articles. In a further embodiment of the invention, the machine additionally including means for longitudinally slitting the web of sheet material prior to the feeding of the web on to the rollers. This is preferably accomplished by a plurality of spaced-apart razor blade slitters. Certain of the foregoing and related objects are also attained in a method of wrapping a generally cylindrical article to package or label same of the type comprising the steps of withdrawing the sheet material from a web, feeding and guiding the web on to an endless transport conveyor, feeding articles on to the web at predetermined intervals, spraying portions of said web with a liquid to permit temporary adhesion of the web to an article to be wrapped, transversely cutting the web after the article has been placed thereon, setting the article into rotation while it engages the sheet material so that the article entrains the sheet material and wraps it around its external periphery, and while it in said engagement, imparting a translational movement to said article along a predetermined path directed transversely of the axis of the rotation of the article, and heating the wrapped article to cause the article to be securely wrapped by the sheet material. The invention provides for heating the wrapped article while the article is transported along the transport conveyor. Preferably, water is used as the liquid in the spraying step. Furthermore, the method preferably includes the step of electronically controlling the acceleration and deceleration of the conveyor. Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are to be used for the purpose of illustration only, and not as a definition of the limits of the invention.
| Number | Name | Date | Kind |
|---|---|---|---|
| 2938319 | Nystrand | May 1960 | |
| 3659394 | Hartleib et al. | May 1972 | |
| 3897671 | Higgins | Aug 1975 | |
| 4262474 | Reuter et al. | Apr 1981 | |
| 4385479 | Focke | May 1983 | |
| 4467589 | Van Maanen | Aug 1984 | |
| 4506488 | Matt et al. | Mar 1985 | |
| 4608807 | Skripalle | Sep 1986 |
