1. Field of the Invention
The present invention relates to a method and apparatus for wrapping products such as napkins, rolls of toilet paper and paper towels. More particularly, the present invention relates to a method and apparatus for the continuous wrapping of products, wherein a continuously fed wrapping material is formed into a tube, articles are fed into the tube, and the tube is separated between the sequential units of products at spaced intervals by a heated cutting element moving along the path of the tube.
2. Discussion of the Related Art
A wide variety of consumer products are mass production wrapped in a heat sealable wrapping material before being delivered to the customer. For example, numerous paper products such as napkins, paper toweling rolls, or toilet paper rolls are wrapped in a thermoplastic material such as polyethylene. The thermoplastic wrapper serves to hold the articles tightly together and to protect them from moisture and abrasion.
As is often the case for products prepared for the consumer mass market, the cost per unit article is strongly dependent on the amount of time required for each operation, including packaging. Known prior art wrapping machines require the product to be displaced from its direction of motion several times during the packaging operation to produce a sealed overwrap of heat sealable material around the product and then to fold and heat seal the ends of the packaging about the product. The displacements and reciprocations of the product within the machine limit the production speed because of the time that must be allocated to such motions. Additionally, the motions of the machine parts required to change the direction of motion of the articles invariably leads to shock and vibration which can become severe as machine speed is increased. In addition, the mechanism for separating the heat sealable material is also crucial to the performance and efficiency of the machine. In many prior art devices, the speed of the wrapping machine is often limited by reason of having to cut a tube transversely as it is continuously fed forward. The cutting step makes it difficult or impossible to achieve a fully compressed or tightly wrapped product.
The below-referenced U.S. patents disclose embodiments that were at least, in part, satisfactory for the purposes for which they were intended. The disclosures of all the below-referenced prior United States patents in their entireties are hereby expressly incorporated by reference into the present application for purposes including, but not limited to, indicating the background of the present invention and illustrating the state of the art.
U.S. Pat. Nos. 2,545,243; 2,982,334; 3,011,934; 3,050,916; 3,133,390; 3,153,607; 3,325,331; 3,576,694; 4,054,474; and 4,084,999 disclose various methods for the formation of a heat sealed wrapper about an article. The devices of many of these references, while somewhat satisfactory for their intended purpose, operate on reciprocating motion and include numerous moving parts in, e.g., their flighted infeed systems. The flighted infeed systems disclosed are often slave driven by the upstream folder machines and as a result, flight jams are commonly caused by timing issues.
U.S. Pat. No. 4,430,844 to James discloses a machine capable of forming sealed wrappers around articles. The machine disclosed in the James patent achieves separation of articles by introducing transverse lines of weaknesses into a flat film at measured intervals representing the wrapper length. The film is then formed into a tube and articles to be wrapped are introduced into the continuously moving tube. Separation into individual packages is achieved as leading wrapped package is pulled forward at a higher speed thereby severing it from a tube at the line of weakness. Although this method works for film or paper wrapping material, special care must be taken to ensure good film tension control as well as perforation geometry in order to avoid premature separation. The machine is also extremely sensitive to variations in film properties and does not allow for product compression.
U.S. Pat. No. 4,218,863 to Howard et al. also discloses a method and apparatus for forming sealed wrappers around articles. The machine disclosed in the Howard patent achieves separation of articles by cutting of the tubular film with a rotating serrated knife. The disclosed method works for film, but it is generally limited to single roll products.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved system, apparatus and method for wrapping articles. It is preferred to have a wrapping machine that can receive articles to be wrapped and form an overwrap on the articles in substantially continuous motion through the machine. It is further desirable for a continuous motion wrapping assembly that allows much higher production speeds to be obtained. There is a further need for improvements to the infeed systems and cutting systems of known continuous motion wrapping assemblies. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.
In accordance with aspects of the present invention an improved system, method and apparatus are provided for wrapping articles such as stacks of napkins, or rolls of paper, (e.g. toilet tissue or paper toweling), at relatively high speed and enabling use of various wrapping materials. In another aspect of the invention, a method and apparatus that allows for continuous wrapping of articles wherein speed is not limited by reason of having to cut or perforate the tube transversely as it is continuously fed forward is provided. In still another aspect of the invention, a method and apparatus which effects separation by thermal cutting with a heated element that moves with the moving product is provided and separates a tube without sealing the tube. In another aspect of the invention, an infeed system for a wrapping assembly that eliminates the use of flight bars and the problems associated with flighted infeed systems is provided. In a further further aspect of the invention, an alternative to infeed systems that are slave driven by upstream folder machines is provided. In another aspect of the invention, an infeed system that allows for the compression of the products as they move through the infeed system such that the product is unaffected by its movement at a high speed is provided.
Consistent with the foregoing, and in accordance with the invention as embodied and broadly described herein, method of wrapping products in a tubular thermoplastic material, a continuous wrapping system and a cutting assembly for a continuous wrapping system are disclosed in suitable detail to enable one of ordinary skill in the art to make and use the invention. In accordance with a first aspect of the invention, the above and other objects are achieved by providing a method of wrapping products in a tubular thermoplastic material. The method includes the steps of forming a continuously moving tube of thermoplastic material from a web of material, delivering spaced product units to be wrapped into the tube and separating the spaced product units in the tube from one another with a heated cutting element.
In one example, the heated cutting element is moveable in two mutually orthoganol directions directions and the step of separating the spaced product units from the tube includes moving the heated cutting element transversely through the tube and horizontally in the same direction as the continuously moving tube of thermoplastic material. The movement of the heated cutting element may match the velocity of the movement of the tube. The step of separating the spaced product units from the tube may include making a first cut in the tube in a downward transverse motion and making a second cut in the tube in an upward transverse motion.
In yet another example, the heated cutting element is mounted on at least one moveable carriage moveable in a first orthoganol direction and the moveable carriage is mounted on at least one carriage arm moveable in an alternative orthoganol direction. The carriage arm may be mounted on a support located adjacent a forming shoulder pull belt and may include a cantilevered heated cutting element. In one example, the spaced product units are at least one stack of napkins. Alternatively, the spaced product units are at least one roll of paper product.
In still another embodiment, a continuous wrapping system includes an infeed system in communication with a supply of product that separates one or more products into units to be wrapped. A tube wrapper forming section is included in the system and configured to form a continuously moving tube of thermoplastic material from a web of material around the units to be wrapped. A cutting assembly is configured to separate the units from one another in the continuously moving tube without sealing the tube. The heated element may be moveable in two mutually orthoganol directions. In one embodiment the speed of the moveable heated element is adjustable in both the transverse and horizontal directions. In one example, the moveable heated element makes a single cut in a cutting cycle. Alternatively, the moveable heated element makes two cuts in a cutting cycle.
In a final embodiment, a cutting assembly for a continuous wrapping system includes a heated cutting element configured to separate units in a tube of plastic material from one another without sealing the tube. The heated cutting element may be moveable in two mutually orthoganol directions. It may be moveable in the same direction and at the same velocity of the tube.
These, and other, aspects of the present invention will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following description, while indicating preferred embodiments of the present invention, is given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.
A clear conception of the advantages and features constituting the present invention, and of the construction and operation of typical mechanisms provided with the present invention, will become more readily apparent by referring to the exemplary, and therefore non-limiting, embodiments illustrated in the drawings accompanying and forming a part of this specification, wherein like reference numerals designate the same elements in the several views, and in which:
In describing the preferred embodiments of the invention that are illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific terms so selected and it is to be understood that each specific term includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. For example, the word “connected,” “attached,” or terms similar thereto are often used. They are not limited to direct connection but include connection through other elements where such connection is recognized as being equivalent by those skilled in the art.
Specific embodiments of the present invention will now be further described by the following, non-limiting examples which will serve to illustrate various features of significance. The examples are intended merely to facilitate an understanding of ways in which the present invention may be practiced and to further enable those of skill in the art to practice the present invention. Accordingly, the below examples should not be construed as limiting the scope of the present invention.
Referring to the drawings, wherein like numerals refer to like parts in each view, an overall perspective view of a continuous motion wrapping assembly or system 20, including a wrapping apparatus or wrapping machine 21 is shown in
As noted above, the illustrated embodiment is directed at wrapping product 22 into compressed packaged units 25. It is contemplated that the invention may be used to wrap units 25 of product 22 comprising, e.g., single stacks or rolls, as well as units 25 of product 22 comprising, e.g., multiple stacks or rolls. As discussed in greater detail below, the units 25 are compressed and encased in a web of continuously moving thermoplastic wrapping material (e.g. polyethylene film) fed forward from a supply roll 24 and formed into a tube 91 around the units 25. At predetermined intervals, the units 25 are fed into the tube 91 one after another and spaced lengthwise in the tube 91 at wrapper length intervals. The tube 91 of wrapping material is then cut at a position between units 25 corresponding to wrapper intervals by a moveable heated cutting element 26 such as a heated knife or wire to form individually girth wrapped units.
Referring to
The sequential product 22 received from the conveyor is then delivered to the infeed system or assembly 28. As illustrated in
Preferably, the infeed compression belts 30 include a lower belt 36 and first 38a and second 38b upper belts driven by an electric servomotor connected to the frame 31. It is also contemplated that a single upper belt could be utilized. As illustrated in
Once the product 22 has moved through the infeed compression belts 30, it is continuously moved through individually servomotor (or other prime mover) driven single registration belts 32a, 32b and twin pack registration belts 33a, 33b of the infeed system 28. The single registration belts 32a, 32b and the twin pack registration belts 33a, 33b space and register the product 22 into preferred units 25. (It is understood that while the described infeed assembly 28 is preferred, prior art spacing means such as spacing bars attached to the belts, could also be used with the inventive cutting system described below.) The single registration belts 32a, 32b and the twin pack registration belts 33a, 33b are preferably programmed or alternatively controlled to move product 22 at multiple varying velocities in their continuous horizontal movement thereby spacing and registering the product into units 25 for wrapping. In addition, the single registration belts 32a, 32b and the twin pack registration belts 33a, 33b may be also compression belts, thereby serving to maintain the product 25 in a preferred girth for packaging and prevent loose product 22, such as napkins, from separating from a stack. It should be understood that the velocities of the single registration belts 32a, 32b and the twin pack registration belts 33a, 33b are selectively adjustable in relation to the velocity of the infeed compression belts 30 and forming shoulder infeed belts 34 to provide for alternative preferred spacing among single stack product units 77 (
Turning to
As the single stack product unit moves off the single registration belts 32a, 32b onto the twin pack registration belts 33a, 33b, the single registration belts 32a, 32b return to moving at a velocity equal to the infeed compression belts 30. Thus, the movement of single stack/product units 77 across the single registration belts 32a, 32b will include at least movement at a velocity equal to the upstream infeed compression belts 30, movement at a velocity greater than the infeed compression belts 30 (and forming shoulder infeed belts 34) and movement at a velocity equal to the downstream forming shoulder infeed belts 34. As noted, once the individual single stack/product unit 77 completes the movement through the single registration belts 32a, 32b, the single registration belts 32a, 32b are again moving at a velocity equal to the velocity of the infeed compression belts 30 and the single registration belts 32a, 32b are ready to receive the next product from the continuous line of product 22. It should be noted that a wide variety of alternative velocities could be set depending on the packaging needs.
As shown in
As described above, the servomotor or other prime mover driven infeed system 28 allows a user to backlog a continuous line of product 22 and separate the product 22 into spaced units 25. Due to the orientation of the single registration belts 32a, 32b and twin pack registration belts 33a, 33b the product 22 may be formed into single stack product units 77 or multiple, such as double stack product units 79. In addition, the product 22 remains compressed without damage to the product from backpressure push. As a result, the in-feed system 28 eliminates the problems associated with prior art flighted infeed systems. It should be understood that in addition to the single 32 and twin pack 33 registration belts, the infeed assembly could include other belts capable of forming, for example three, four or more aligned stacks of product 22.
Upon exiting the single registration belts 32a, 32b or the twin pack registration belts 33a, 33b of the infeed assembly 28, single stack product units 77 or double stack product units 79 (
A variety of known tube forming mechanisms could be utilized and incorporated into the inventive wrapping system 20. In the preferred embodiment, a web 50 of thermoplastic material is positively continuously pulled from the supply roll 24 and fed forward in a horizontal path towards the tube wrapper forming section 40 of the wrapping assembly 20. The web is preferably driven by a prime mover such as a servomotor at the same velocity as the forming shoulder product-pull belts 58a, 58b which are downstream in the horizontal path of the forming shoulder infeed belts 44a, 44b. The web then travels forward from the rolls 52, 54 until its is redirected by a turning bar (not shown). The web then travels rearward relative to a tube feed means (not shown), and is trained under and up around a guide roll to the tube forming shoulder 60. The tube forming shoulder 60 is generally known in the art, with minor modifications for purposes of this invention. The forming shoulder is arranged such that as the web 50 travels up and around the shoulder 60, it is formed into a tube and, as it proceeds through a tubular guide, it becomes wrapped around the single stack product units 77 or double stack product units 79 as is known in the art. The single stack product units 77 or double stack product units 79 are also pulled forward and delivered into the tube 91 by forming shoulder product pull belts 58a, 58b. The product pull belts 58a, 58b are also driven by a servomotor or other prime mover at an adjustable speed corresponding to the movement of a heated cutting element 26 as discussed below.
The forming shoulder product pull belts 58a, 58b and the web feed rolls 52 feed the web 50 forward from the supply roll 24 to the forming shoulder 60 where the web 50 is formed into the tube 91 at a predetermined speed. For example, in the case of a single stack product units 77 with dimensions of 5″ wide by 5″ long by 2″ high the speed may be 80 feet per minute (corresponding to a rate of 120 units per minute). As illustrated, the forming shoulder product pull belts 58a, 58b feed the tube with the product therein forward at a predetermined speed. A drive device, preferably a servomotor, is provided for continuously driving these forward. The single stack product units 77 or double stack product units 79 inside the tube act as a back-up for the forming shoulder product pull belts 58a, 58b. The forming shoulder product pull belts 58a, 58b are preferably vacuum belts, having vacuum holes, and vacuum boxes being provided on the inside of their forward traveling reaches, for effecting vacuum gripping of the tube by the forming shoulder product pull belts 58a, 58b via the holes. Alternatively, each of the forming shoulder product pull belts 58a, 58b may be composed of a flexible material having relatively good surface friction with respect to polyethylene and other thermoplastic materials, such as a fabric backed rubber belt or certain flexible plastic belts. The upper belt 58a, like the other belts in the system may be adjustable toward and away from the lower belt 58b. Preferably the forming shoulder 60 is removable and replaceable with forming shoulders of different sizes and shapes for accommodating different products 22.
Once the spaced single stack product units 77 or double stack product units 79 have moved through the forming shoulder, the formed tube with the single stack product units 77 or double stack product units 79 is driven along the forming shoulder product pull belts 58a, 58b to the cutting assembly 70 of the wrapping system 20. The contact between the belts 58a, 58b and the tube 91 formed around the single stack product units 77 or double stack product units 79 maintains the tube 91 relatively taut and closely drawn around the product 22 within. Friction belts (not shown) may apply longitudinal tension about the periphery of the tube 91 to pull the material tight against the product 22 within.
Turning to
Support 82 includes a pair of upper 86a and lower 86b horizontal beams extending between a pair of vertical beams 88a and 88b. A pair of horizontal carriage arms 90a, 90b are respectively moveably mounted on the pairs of vertical beams 88a, 88b. The carriage arms 90a, 90b are configured to move vertically in a synchronized fashion along vertical beams 88a, 88b. The carriage arms 90a, 90b are preferably driven by belts driven by servomotors 92, 93 or other prime movers mounted to the support 82. As illustrated in
It is recognized that the thermal cutting of a tubular cross section of tube 91 wrapped around the stack product units 77 or double stack product units 79 could be achieved with numerous different designs whereby the horizontal motion of enclosed articles and a heated cutting member is synchronized during a cutting cycle in order to produce a substantially perpendicular cut, without sealing the tube 91, to the direction of film travel. For example a heated cutting element 26 may be attached to a rotating mechanism or other articulated means to achieve film separation.
As discussed in greater detail below, one preferred embodiment of the invention utilizes a cutting path wherein separation of tube 91 by heated cutting element 26 takes place during one half of the cycle in a downward transverse direction and the heated cutting element 26 is then returned to its starting position along the formed cut line. In an alternative embodiment, during the return motion to starting position a second cut is made.
Following the brief pause, the heated cutting element 26 continues its cutting cycle with upward transverse and horizontal motion asymmetrical to that occurring between positions 101 through 104. The movement of the heated cutting element 26 from positions 104 to 106 includes an upward or transverse component as well as a horizontal component. The horizontal component is in the same direction and at a velocity equal to the velocity of the horizontal motion of the product 22 and tube 91. As the heated cutting element 26 moves between positions 105 and 106 it is following the path of the previously formed cut 112. Between position 106 and 107, the heated cutting element 26 is no longer in the continuously moving tubular plastic 91 and it proceeds in solely transverse motion upward. Once the heated cutting element 26 completes its upward motion at position 107 it proceeds horizontally in a direction opposite the motion of travel of the product 22 and tube 91 back to position 101. The cycle is then repeated to form additional cuts.
At position 205, the heated cutting element 26 continues its cycle with an upward transverse motion. As illustrated, between positions 205 and 206, the motion of the heated cutting element 26 includes a vertical or transverse component as well as a horizontal component. The horizontal component is again at a velocity equal to the velocity of the horizontal motion of the units 25 and tube 91 and in the same direction. As the heated cutting element 26 moves between positions 205 and 206 a new second cut 120 is formed. At position 207 the heated cutting element 26 has completed the second cut 120 and is no longer in the continuously moving tubular plastic 91. The heated cutting element 26 then proceeds vertically and horizontally in a direction opposite the motion of travel of the product 22 and tube 91 back to position 201.
In operation, the web 50 is continuously drawn from the supply roll 24 and fed forward at the requisite speed. As it travels forward, the web travels around rolls, up to the forming shoulder 60 of the tube wrapper forming section 40, around the shoulder 60 and into and through a guide of the former. One or multiple spaced products 22 are continuously fed forward in units 25, one after another, by the infeed assembly 40 coming into position on the web 50 as it travels forward. The web is formed into the tube 91 around the units 25 of product, the tube with the units 25 therein being drawn forward at a predetermined tube feed speed by the forming shoulder product pull belts 58a, 58b. As the leading (downstream) end of the tube 91 enters the cutting assembly 70, the moveable heated cutting element 26 engages the tube to sever it between a leading edge and the remainder of the tube as the knife exit belts 84a, 84b pull the leading cut tube 91 with the units 25 therein forward. The heated cutting element 26 either returns along the cut line 116 or forms a second cut 120 in the tube 91 to sever the tube with the unit 25 therein away from the tube. If the second cut 120 is not formed in the single cycle illustrated in
It will be observed that the wrappers surrounding the products are, in effect, measured as a result of the timed relation between the speed of feed of the web 50, the speed of the single registration belts 32 and the twin pack registration belts 33 and the speed of the heated cutting element 26 moving through the tube. It should also be understood that the in feed compression belts 30, the single registration belts 32 and the twin pack registration belts 33, the forming shoulder infeed belts 44a, 44b, the forming shoulder product pull belts 58a, 58b, the knife exit belts 84a, 84b and the movement of the heated cutting element 26 are all servomotor driven. Each servomotor can be readily adjusted to allow for alternative spacing of the units 25 within the tube 91.
Although the best mode contemplated by the inventor of carrying out the present invention is disclosed above, practice of the present invention is not limited thereto. It will be manifest that various additions, modifications and rearrangements of the features of the present invention may be made without deviating from the spirit and scope of the underlying inventive concept.
Moreover, as noted throughout the application the individual components need not be formed in the disclosed shapes, or assembled in the disclosed configuration, but could be provided in virtually any shape, and assembled in virtually any configuration, so as to provide for a wrapping system that includes a programmable infeed system and a cutting system that uses a moveable cutting element.
Furthermore, all the disclosed features of each disclosed embodiment can be combined with, or substituted for, the disclosed features of every other disclosed embodiment except where such features are mutually exclusive. For example, although a preferred infeed system 28 is disclosed, it is recognized that other infeed systems including prior art infeed systems could be used with the inventive cutting assembly 70.
It is intended that the appended claims cover all such additions, modifications and rearrangements. Expedient embodiments of the present invention are differentiated by the appended claims.
Number | Name | Date | Kind |
---|---|---|---|
2296142 | Campbell | Sep 1942 | A |
2931148 | Smith | Apr 1960 | A |
3229442 | Gram | Jan 1966 | A |
3438173 | Omori | Apr 1969 | A |
3664088 | Sherman | May 1972 | A |
3800498 | Suzuki | Apr 1974 | A |
3925139 | Simmons | Dec 1975 | A |
3973372 | Omori | Aug 1976 | A |
4017713 | Lodi | Apr 1977 | A |
4048885 | Miyakita et al. | Sep 1977 | A |
4317322 | Lancaster et al. | Mar 1982 | A |
4429513 | Beckers et al. | Feb 1984 | A |
4525977 | Matt | Jul 1985 | A |
4590735 | Dohrendorf | May 1986 | A |
4738079 | Lancaster et al. | Apr 1988 | A |
4796499 | Achelpohl | Jan 1989 | A |
4860621 | Totani | Aug 1989 | A |
4870802 | Cerf | Oct 1989 | A |
5079902 | Seko et al. | Jan 1992 | A |
5140800 | Martin et al. | Aug 1992 | A |
5195300 | Kovacs et al. | Mar 1993 | A |
5205808 | Gebhardt | Apr 1993 | A |
5244449 | Totani | Sep 1993 | A |
5271210 | Tolson | Dec 1993 | A |
5285621 | Ballestrazzi et al. | Feb 1994 | A |
5329745 | Suga | Jul 1994 | A |
5337542 | Omori | Aug 1994 | A |
5347791 | Ginzl et al. | Sep 1994 | A |
5351464 | Francioni | Oct 1994 | A |
5374232 | Cipollone | Dec 1994 | A |
5410800 | Gray | May 1995 | A |
5475964 | Fiesser et al. | Dec 1995 | A |
5524420 | Ikuta | Jun 1996 | A |
5564261 | Kiner | Oct 1996 | A |
5653085 | Suga | Aug 1997 | A |
5689942 | Suga | Nov 1997 | A |
6003288 | Sperry et al. | Dec 1999 | A |
6050065 | Bonde | Apr 2000 | A |
6254521 | Pansier et al. | Jul 2001 | B1 |
6557322 | Strasser | May 2003 | B2 |
6629400 | Offermann et al. | Oct 2003 | B1 |
6662527 | Suga | Dec 2003 | B1 |
6854242 | Stork et al. | Feb 2005 | B2 |
6898922 | Reist | May 2005 | B2 |
20030159401 | Sorenson et al. | Aug 2003 | A1 |
Number | Date | Country | |
---|---|---|---|
20080072545 A1 | Mar 2008 | US |