Package making – Methods – Closing package or filled receptacle
Reexamination Certificate
2000-05-25
2002-06-25
Rada, Rinaldi I. (Department: 3721)
Package making
Methods
Closing package or filled receptacle
C053S567000
Reexamination Certificate
active
06408600
ABSTRACT:
BACKGROUND
A. Wrapping Apparatus and Process
This invention relates to machines for packaging individual rolls or groups of rolls in a film. Such machines are described in detail in U.S. Pat. Nos. 5,433,063, 5,228,273, 4,430,844, 5,255,495 and U.S. patent application Ser. Nos. 08/147,153 and 08/143,455 now U.S. Pat. No. 5,462,013.
Such packaging machines are particularly useful for wrapping rolls of bathroom tissue or household paper towels. Such rolls conventionally include a core and paper wound around the core. One or more wound rolls are overwrapped with a tube of plastic film, and the edges of the film are sealed to form a package.
Prior to this invention, the overwrapping process was continuous motion, consisting of multiple lane product infeed choke belt conveyors. The conveyors feed product in time to a flighted chain conveyor in the desired package format across a dead plate to an overhead chain conveyor with attached product pusher paddles. The product continues to be conveyed in time, pushed by the overhead conveyor pusher paddles across another dead plate to a girth former which overwraps the product with continuously unwound film from an unwind positioned at 90° to the flow of product through the machine. The film entubes the product is then overlapped and sealed in a longitudinal direction. The wrapped product is advanced downstream via conveyor pull belts, and perforations in the film produced at the unwind section are severed by timed paddles which impinge the sealed tube of film exactly where the circumferential perforations are positioned exactly halfway between the entubed wrapped products. At this point, the longitudinally sealed overwrapped product becomes separated at the film perforations. Film extending beyond the ends of the product remain for sealing the ends of the package downstream later in the process.
The product continues to be transported via conveyor belts and then is transferred by an overhead chain conveyor with pushers attached which are timed to convey product at 30° to the direction of flow. Another chain conveyor with pushers attached traveling beneath a dead plate on which the product rests intercepts the product and pushes it a full 90° from the initial direction of travel. While the product continues to be conveyed, air blasts, fixed slotted plates, and flex wipe brush conveyors guide and fold the film on the ends of the product in the same manner as if wrapping a gift. Once the film has been folded, the product is conveyed between moving Teflon® belts which transport the product via the ends of the package. The belts pass over spring loaded fixed heaters to seal the plastic film on the package ends. The belts continue to transport the package through an unheated area while still maintaining the package under compression to permit cooling of the sealed film.
Products can be packaged with cores up or down and in one or two levels of product. A customer perforation can also be added to the package as an option provided in the film unwind section. The machine sections are driven by a plurality of AC servo motors at guaranteed speeds for individually wrapping rolls of household paper towels at up to
250
packages per minute (ppm).
B. Sealing Dies
The ends of the package are sealed by top and bottom sealing dies which close on the film between products. U.S. Pat. No. 5,433,063 describes how the sealing dies (and half dies) are positioned on belts (two half dies located 180° apart on each belt), how they are driven, the velocity profile of the dies, how power is transmitted to the belts, and the ability for the dies to be rotated about shaft interlinks on the pairs of belts to which they are attached. The sealing dies include four sealing wires and a cutoff knife.
U.S. Pat. No. 5,433,063 also describes multiple axes for independently driving each of the die sets at a variable velocity. The velocity of the axes relative to one another may be changed during a package making cycle without one die set interfering with any other die set. The actual velocity and acceleration of any given die at various positions within that die's travel is described in the patent.
The relationship of the velocity and acceleration of each die half with respect to the position of that die half within its travel is referred to as the motion profile. The profile described in the patent is based around the velocity of the film. The velocity of the die is equal to the film velocity as the die half makes contact with the film. The die half then slows down to collapse the film between the bundles. As the die continues around the radius of the pulley, it begins to accelerate back to film velocity. The die half (with the bundle in front of it) will travel at film velocity until the next die half (following the current one) touches the film. Then the first die half decelerates to allow the next die half to collapse the film tube. After that die half finishes collapsing the film tube, both will accelerate back to film velocity.
In U.S. Pat. No. 5,433,063, although not described, cam tracks are used in conjunction with cam followers mounted in various locations on the half dies. Together they serve as a means to control the orientation and path of travel of the half dies. The patent goes on to describe in column 3 that speeds of 45 packages per minute are attainable. This capability is based on a combination of the software programming for the velocity profile of the dies, the size of the servo motors/motion controllers, the inertia based on the weight of the dies and driven components, and the cam track geometry.
SUMMARY OF THE INVENTION
A. Wrapping Apparatus and Method
Like existing prior art, the invention is also a continuous motion apparatus and process. The invention may also incorporate a similar multiple lane product infeed choke belt conveyor and flighted chain conveyor. At this point the process can begin to differ. The ability to converge product in this area from three or four lanes of product rather than converging product upstream with a separate product diverting conveyor can be provided. Product then transfers from the flighted chain conveyor in time to an overhead conveyor with pushers that push product in time across a dead plate to the girth former. The machine can have a standard forming shoulder overhead and drop away dead plate. A girth former which is breathable or fixed overwraps product with continuously unwound film from an unwind positioned under the drop away dead plate in line with the machine. The film is not perforated. However, the film does entube the product and is then overlapped and sealed in a longitudinal direction in a manner similar to existing art. The entubed product continues downstream via conveyor side pull belts on either side of the product along with top and a bottom conveyor belts, again like existing art. Top pull belts can be substituted with fixed product hold down guides.
Unlike the prior art, this process continues in a straight line where product from the pull belt section transfers over a fixed dead plate and gap to the sealing section. The entubed product begins to travel at a slightly reduced speed, causing the pitch between the products to shorten. At this point the film gussets are tucked by timed air blasts simultaneously on each side of the package just before servo driven traveling top and bottom sealing dies close on the film between the packages. An impulse of current simultaneously seals leading and trailing packages on either side of the sealing dies and cuts the film to separate the packages. All of this is accomplished with one sealing/cutting wire. With a simplified die design, higher operating speeds are possible. Higher speeds are also made possible through the use of programming the software for the drive controllers of the servo motors to provide the appropriate velocity profile of the sealing die to achieve a given operating speed.
This process has been designed to package a single roll of household paper toweling or four rolls of bathroom tissue in a cores down application at an operating speed
Brugman Matt L.
Ginzl Jeffrey A.
Hopkinson Brian L.
Monigal Neal R.
Nankervis Wayne T.
Desai Hemant M
Paper Converting Machine Company
Rada Rinaldi I.
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