Abstract:
A method and apparatus for making bags, including winding bags, is disclosed. The winder includes spindles with sleeves. The sleeves may have holes, be non-stick, removable, and may be tapered. They can be fitted to existing machines.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates generally to the art of bag machines. More specifically, it relates to a bag machines with winders, or to a winder for a bag machine.  
       BACKGROUND OF THE INVENTION  
       [0002]     There are many type of bag machines that form bags from film or process already formed bags. These machines may use a variety of processing or forming techniques. Bag making machine, as used herein, includes a machine that converts film into bags, or receives bags and further processes them, such as perforating, separating, winding, etc.  
         [0003]     Some machines include a winder, wherein bags are fed to a winder and wound into a roll. Some prior art winders include a turret with spindles mounted on the turret. The turret rotates a metal spindle to a position where the film initially contacts the spindle, and the roll is started to be wound. After the film has been wound sufficient to start the roll the turret can be moved so that the spindle is in a winding position. Also, a second spindle on the turret is now in the starting position. When the roll is completely wound, the film is directed to the spindle that is now in the starting position. The process then repeats, winding the new roll, and moving the next spindle into the starting position. Also, the wound rolls are pushed off the spindle. U.S. Pat. Nos. 4,667,890 and 6,186,436 are examples of prior art winders, and are hereby incorporated by reference.  
         [0004]     The prior art encounters problems such as difficulty in removing wound rolls, and wear of the spindle where it meets the inner surface of the rolls. The problem of removal has been addressed at length by tapering the spindle, and/or including counter sunk air holes in the spindle. Air blown through the holes helps make it easier to push the rolls off the spindle. However, the inner bag can stick to the counter sunk holes, and be damaged when the roll is pushed off. Also, spindles have been coated with high-release materials, to lessen friction between the inner bag and the spindle. However, this exacerbates the wear problem.  
         [0005]     The high speed operation of bag machines causes the spindle to wear. The wear can be faster for a coated spindle than a metal surface spindle, but wear can occur in any event. It can be difficult and time consuming to change remove and replace a spindles, particularly when they are connected to an air supply. Of course, the down time when the spindle is being replaced is costly in that no bags are produced while the spindle is being replaced.  
         [0006]     Accordingly, a winder that has a spindle with a surface that may be easily replaced is desirable. Preferably the surface will be non-stick, and will not damage the inner bag.  
       SUMMARY OF THE PRESENT INVENTION  
       [0007]     According to a first aspect of the invention a bag making machine includes an input stage, a processing stage that receives film from the input stage, and a winder that receives bags from the processing stage. The winder has a turret with spindles. Each spindle has a sleeve over it.  
         [0008]     According to a second aspect of the invention a method of making and winding bags includes receiving a film and converting the film into a plurality of successive bags. The bags are wound about a sleeve mounted on a spindle to form a roll of bags. Air is blown through the sleeve and the bags are removed from the sleeve.  
         [0009]     According to a third aspect of the invention a winding assembly for bags made from film includes a turret with spindles mounted thereon. Sleeves are placed over the spindles.  
         [0010]     According to a fourth aspect of the invention a method of winding rolls of bags includes receiving formed bags, winding the bags about a sleeve mounted on a spindle to form a roll of bags. Blowing air through the sleeve, and removing the bags from the sleeve. The turret is rotated to move a second spindle with a second sleeve mounted thereon into a position for receiving bags.  
         [0011]     According to a fifth aspect of the invention, a sleeve for a winding assembly of a bag machine includes an outer surface and a hollow interior. The sleeve is mountable on a spindle on turret in the winding assembly.  
         [0012]     According to a sixth aspect of the invention a method of repairing a winding assembly on a bag machine includes removing a sleeve from a spindle, leaving the spindle attached to the turret and placing a second sleeve over the spindle.  
         [0013]     The sleeves are comprised completely of non-stick material in one alternative, and have a non-stick outer surface in another embodiment. The sleeves can have an inner portion comprised of metal or other material.  
         [0014]     The non-stick material is polytetrafluoroethylene, nylon, or UHMW-PE in other embodiments.  
         [0015]     Each sleeve is removable without removing the spindle it is over in another embodiment.  
         [0016]     Each sleeve has holes for air flow therethrough in another embodiment. The holes may be spaced radially and axially about each sleeve. Also, the spindles may be hollow, and have inner holes, and be connected to a source of air, so that air flows through each spindle and out the holes.  
         [0017]     The sleeves may be generally cylindrically shaped in another embodiment. The spindles may have a threaded receptacle to receive a bolt that extends through the sleeve to the spindle and attaches the sleeve to the spindle.  
         [0018]     The sleeves may be tapered so that the outer end is narrower than the inner end in various embodiments.  
         [0019]     The sleeves can be is affixed over the spindles so the sleeves cannot rotate with respect to the spindles.  
         [0020]     The sleeves may be replaced without replacing the spindle.  
         [0021]     Other-principal features and advantages of the invention will become apparent to those skilled in the art upon review of the following drawings, the detailed description and the appended claims.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]      FIG. 1  is prior art bag machine;  
         [0023]      FIG. 2  is sleeve in accordance with the preferred embodiment;  
         [0024]      FIG. 3  is the sleeve of  FIG. 2 , rotated 90 degrees;  
         [0025]      FIG. 4  is spindle in accordance with the preferred embodiment; and  
         [0026]      FIG. 5  is the spindle of  FIG. 2 , rotated 90 degrees. 
     
    
       [0027]     Before explaining at least one embodiment of the invention in detail it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting. Like reference numerals are used to indicate like components.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0028]     While the present invention will be illustrated with reference to a particular machine and in a bag making environment, it should be understood at the outset that the invention can be implemented on other bag machines and in other environments, and with other sleeve designs.  
         [0029]     Generally, the invention provides that a winder for a bag machine include a sleeve over each spindle. Sleeve, as used herein, includes a structure that is placed over a spindle, and about which a roll of bags is wound. The sleeve contacts the inner surface of the roll of bags. The sleeve can have an outer surface of (or be made entirely of) a material that is non stick, such as polytetrafluoroethylene, nylon, UHMW-PE, is tapered, and includes air holes to make removing wound rolls easier. Also the sleeve preferably is attached to the spindle such that it cannot rotate. In the preferred embodiment the sleeve is a threaded bolt serves as an end cap to the sleeve, and threads into a receptacle in the spindle, thus holding the sleeve to the spindle. The sleeve also includes a hole near the axial end closest to the turret. A screw passes through the hole, and into the turret, to prevent the sleeve from rotating with respect to the turret. Thus, the sleeve is easily removed and replaced, when the sleeve wears, and helps make it easier to remove rolls.  
         [0030]     Non-stick surface, as used herein, includes a surface that film or bags adhere to less than surfaces traditionally used in bag machines, such as metal or rubber. Examples of non-stick surfaces include polytetrafluoroethylene, nylon, UHMW-PE (ultra-high molecular weight polyethylene) and some other polymeric materials.  
         [0031]     The invention may be implemented on known bag machines and winders, such as those shown in U.S. Pat. Nos. 4,667,890; 6,186,436; and 5,390,875 (hereby incorporated by reference), or commercially available winders such as the CMD 4014®, the CMD R0 4213®, or the CMD 0305GOW®. Also, the invention may be retrofitted to existing machines quite easily. Winder, as used herein, includes a device for winding bags, either separated or attached, and often includes a turret, spindles, and can include other components such as a rotary overlap stage.  
         [0032]     The preferred embodiment will be described with reference to the known bag machine of U.S. Pat. No. 5,390,875, as shown in  FIG. 1 . A winder or bag machine  100  may be operated in either a continuous or interleaving mode, and includes a dancer assembly  101 , a haul-in assembly  102 , a tumbler assembly  103  and a winding assembly  104 . In operation a strip of film  105 , suitably made of plastic or another pliable material (which may be provided either directly from a bag making machine or from a premade roll of bags) passes through dancer assembly  101  to haul-in assembly  102 . From haul-in assembly  102  film  105  is provided to tumbler assembly  103  and then to winding assembly  104 . Machine  100  may be operated as known in the prior art. Specifically, winding assembly  104  operates in a manner similar to that of the prior art. The bags are counted, to determine when an air horn is activated and when the turret should rotate.  
         [0033]     Dancer assembly  101 , haul-in assembly  102 , and tumbler assembly  103  are called processing stages. Dancer assembly  101  is also called an input stage. Processing stage, as used herein, includes a part of the bag machine that process film or bags, such as knifes, winders, rotary overlappers, sealers, etc. Input stage, as used herein, includes the part of a bag machine that receives film from a film source, or formed bags from a source of bags.  
         [0034]     The invention provides for a sleeve to be placed over some or all of the spindles one the turret of winder  104 .  FIGS. 2 and 3  shows a sleeve  200  in accordance with the preferred embodiment, wherein the view of  FIG. 3  is the view of  FIG. 2 , with sleeve  200  rotated 90 degrees. A plurality of holes  201  are spaced axially along sleeve  200 , as well as spaced radially around sleeve  200  to allow for air flow to be used to make removal of the roll easier. Holes  200  are preferably not counter sunk. The spacing is shown to be equal axially (for example every two inches), and at every 90 degrees radially, but can be other patterns or unequal spacing in other embodiments. Spaced radially or axially, as used herein, includes holes at regular or irregular radial or axial locations on the sleeve such that all holes are not in a single cross section.  
         [0035]     Sleeve  200  is preferably made of solid polytetrafluoroethylene. Other embodiments provide for it to be made of nylon, UHMW-PE (ultra-high molecular weight polyethylene), other polymeric materials, or other non-stick materials. Other embodiments provide for the surface to be a non-stick coating over another material (metal, e.g.).  
         [0036]     As shown in  FIGS. 2 and 3 , sleeve  200  has a generally cylindrical shape. It has a slight taper toward an outer axial end (the left on  FIGS. 2 and 3 ), of about 0.062 inch/foot in the preferred embodiment. Generally cylindrically shaped, as used herein, includes shapes close to cylindrical, such as being axially tapered, have a varying cross section, or the axial ends can be uneven or at a varying distance from one another. Outer axial end, as used herein, refers to the end of the sleeve or spindle away from the structure that supports the spindle, such as the turret.  
         [0037]     Sleeve  200  is provided with pair of holes  207  at the inner axial end and an end cap  203  at the outer axial end. End cap  203  includes a threaded portion and holds sleeve  200  on its respective spindle. A screw inserted through holes  207  into the spindle prevents sleeve  200  from rotating on its respective spindle. Respective spindle, as used herein, refers to the spindle on which a particular sleeve is mounted.  
         [0038]     Referring now to  FIGS. 4 and 5 , a spindle  400  includes a plurality of holes  401 . Also, spindle  400  has a hollow inner end  402  that receives air form an air source. Thus, the air flow path is from end  402 , though holes  401 , and out holes  301 . Holes  401  are preferably spaced radially and axially, but can have other arrangement. They can either be aligned with, or not aligned with, holes  301 .  
         [0039]     Spindle  400  includes a pair of threaded holes  404  which receive a screw that passes though holes  207 , to stop sleeve  200  from rotating with respect to spindle  400 . Spindle  400  also has a threaded receptacle  406  to receive end cap  203 , thus holding sleeve  200  to spindle  400 .  
         [0040]     Sleeve  200  may be easily replaced by removing the screws from holes  207  and removing end cap  203 , taking off the sleeve, placing the new sleeve on the spindle, and replacing the screws and end cap. A sleeve is removable without removing the spindles, as used herein, when the sleeve may be replaced without removing the spindle from the turret.  
         [0041]     Numerous modifications may be made to the present invention which still fall within the intended scope hereof. Thus, it should be apparent that there has been provided in accordance with the present invention that fully satisfies the objectives and advantages set forth above. Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.