Special receptacle or package – Plural paper bags
Reexamination Certificate
2001-02-16
2003-08-05
Fidei, David T. (Department: 3728)
Special receptacle or package
Plural paper bags
C383S009000
Reexamination Certificate
active
06601707
ABSTRACT:
TECHNICAL FIELD OF INVENTION
The invention relates to thermoplastic bags which are stacked and blocked or unitized to be configured as a bag block. Furthermore, the invention relates to a method of successively filling the bags and separating the filled bags from the bag block.
BACKGROUND OF THE INVENTION
The prior art related to the subject matter of the present invention includes U.S. Pat. Nos. 4,451,249; 4,342,564; and 4,699,607; PCT publication WO 99/48677; and European Patent EP 1 036 741, all herein incorporated by reference. Pending U.S. Ser. No. 09/517,968, filed Mar. 3, 2000, is also herein incorporated by reference.
Bag blocks are used in food packaging assembly lines for bagging successively delivered products such as bread loaves. In the manufacture of bag blocks, one approach is described in U.S. Pat. No. 4,699,607 which involves producing two bags from each web segment or sheet wherein each segment is provided with a line of perforations defining a generally circular enclosed area located equidistant from the opposed edges of the sheet. A stack of such sheets is carried by a support, supporting a central medial band of the sheets. The sheets are unitized or blocked by a heated member projecting through the sheets in the perforated circular area of the sheets. To produce individual bag blocks, the sheet stack is cut along a line through the central medial band of the sheets.
For a wicketed bag stack, holes can be prepunched into the sheet within or outside of the circular perforated area, before the sheets are stacked, and posts are provided on the support for receiving the succession of sheets impaled thereon via the prepunched holes. The subsequently blocked stack of wicketed bags is moved to a filling station wherein bags can be dispensed from the bag block by tearing individual bags from the bag block.
Another method of forming a bag block follows the following steps:
unwinding a layer of flat web of film from the unwind stand;
folding the web of film over a folding board;
applying a gusset in the web of film;
entering the web of film into the bag forming machine via the infeed section;
passing the intermittant moving part of the bag forming machine whereby a number of operations are done to the web, including the application of a perforation pattern;
forming the bags by means of a sideweld or mixed weld sealing head;
picking up and stacking bags on an index conveyor or an automated wicket handling system; and
unitizing the stack of bags.
The unwind step can be accomplished by a standard Hudson-Sharp Machine Co. model SDU 1600 unwind stand. It is an electrical surface-driven and braked unwind with a compensator for perfect web tension control. A web guiding system ensures a centered web exiting the unwind stand.
The pre-centered web is pulled over the folding board by the infeed section of the bag machine, thereby forming a J-folded web whereby the lip is typically 35 to 45 mm wide. The folding board is a standard Hudson-Sharp Machine Co. 1500 mm folding board accessory. Optionally a bottom gusset is formed in the J-shaped web. The gusset former is a standard Hudson-Sharp Machine Co. 750 mm gusset former accessory.
The infeed section is the first section of the Hudson-Sharp Machine Co. model 4750W basic wicket machine. It pulls the J-folded web into the bag machine from the gusset former, folding board and unwind by means of a set of nip rolls typically driven by an AC motor. This AC motor is controlled by a frequency controller which obtains a speed reference from the main machine controller and the infeed dancer which is part of the infeed section and located just stream downwards of the nip rolls.
As a standard feature on the Hudson-Sharp Machine Co. model 4750W basic wicket machine, the intermittent moving part of the machine consists of two sets of servo driven nip rolls. In between the two pairs of nip rolls several attachments will modify the web of film such as by punching wicket holes for stacking and/or will detect the photo-eye mark for print registration. The formation of the bag is done in the sealing section of a standard Hudson-Sharp Machine Co. model 4750W. Typically the seals are side seals but mixed weld seals are also possible.
The picking up and stacking of the bags is done in the pick-up and conveyor section of a standard Hudson-Sharp Machine Co. model 4750W. Wicketed bags have wicket holes. Wicket holes have heretofore been circular, triangular, star shaped, or diamond shaped. The bags are stacked on wicket pins going through the wicket holes during stacking. Although this stacking method produces the most ordered stacking quality, it isn't a necessity. The bags can be made without any kind of stacking holes and be stacked on needles. The unitizing of the stack can be done with a standard Hudson-Sharp Machine Co. pin blocker. Accordingly, heated pins can be driven through the stack of bags. The unitizing is done in the lip area above a region of perforations. The subsequently blocked stack of wicketed bags is moved to a filling station wherein bags can be dispensed from the bag block by tearing individual bags from the bag block. During the filling operation perforations are broken to create an opening of each bag large enough to receive the product being packaged.
A method of filling and separating successive bags is described by the following steps:
putting a stack in a stack recipient box and indexing the box to the bag filling area;
opening the bag with an air nozzle or suction device;
inserting the bag opening device or “spoons;” inserting the product into the bag;
pulling the bag off the stack together with the product; and
closing the bag and putting the bag on an offload conveyor.
The Ibonhart model IB 360 filler feeds each stack of bags into the filling area by means of a “recipient box.” In a preparation station, an operator puts a stack of bags into a recipient box. When the recipient box in the filling area is empty, it is transferred away from the filling area and a prefilled new recipient box is placed into the filling position. In this process the stacks are presented substantially horizontally in the recipient box. A slight downward angle in the gusset area (i.e., bottom area of the bags when oriented upright) can be applied to lower the gusset area.
Once the filling starts or restarts, bags are removed from the recipient box in the filling station. An air blast, aimed towards the opening of the top bag initially opens the top bag. Once the bag is opened, a set of spoons is inserted into the bag. The spoons engage the mouth of the bag and open it to a somewhat rectangular shape which corresponds to the shape of the product to be packaged. At this moment the bag is held by the spoons but is still connected to the rest of the stack by means of the wicket wire via the wicket holes. By means of a pusher the product is pushed into the bag. When the product hits the bottom of the bag, the still moving pusher will rip off the bag from the stack over the wicket wire. According to another known method, the spoons open the bag and then draw the bag in a reverse direction to the direction the spoons entered the bag, i.e., in a forward direction, to separate the bag from the block and at the same time to capture a stationary product within the moving bag. According to either method, the product together with the bag is then brought into another area of the filler where the bag is closed and transported for further handling.
As the stack is depleted, the recipient box is moved vertically upward to maintain an equal filling plane. The filled bag is pulled off the stack, over the wicket wires. Since the bag is completely removed after each fill, the top of the remaining stack has full clearance without leaving any scrap which could interfere with the filling process. However, the entire lip is removed with the bag which can constitute an undesirable extra flap connected to each bag.
Another method of filling a succession of bags is described in Australian published application AU 20002280 A1. According to this reference, a stack of
Fidei David T.
Hudson-Sharp Machine Co.
Wood Phillips Katz Clark & Mortimer
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