Abstract:
A slitting apparatus mountable to a web handling apparatus, for slitting a thin web of a first width into plural ribbons each of width less than the first width. The slitting apparatus may comprise at least one enclosed motorized rotatable blade mounted on a rotatable shaft and a stationary base which is screw mountable to the web handling apparatus. The blade is movable between a slitting position for slitting operations and a service position spaced away from the slitting position, for blade replacement. A step-down gearset reduces blade rotational speed from the motor speed. A manual shifting element comprising a manual lever and a cam effects change between the slitting and service positions. The blade may be entirely ceramic or ceramic coated. A roller shaft may be located proximate the blades to maintain tension on the web and to obstruct direct access to the blades for safety purposes.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to severing or slitting an elongated film into plural ribbons each of less width than the original supply, and more particularly, to a motorized slitting apparatus adapted to facilitate replacement of circular slitting blades thereof. 
       BACKGROUND OF THE INVENTION 
       [0002]    Articles such as packages of beverages must typically be transported for retail distribution on pallets. The beverages may be canned, bottled, or otherwise supplied in containers for use by the ultimate consumer. Cans, bottles, and the like are typically prepared for retail sale by ganging a number of containers together. This may be accomplished by providing a plastic yoke which engages the necks of a predetermined number of individual bottles, such as six bottles, and holds these bottles together as a unit. A number of cans, bottles, or the like, again using the example of six such containers may be held together by shrink wrapping a film about these containers. Regardless of the precise nature of grouped or ganged containers, they must be transported in considerable quantities as they move through distribution channels from a factory to a retail point of sale. Contemporary practice is to load a wooden pallet with the ganged containers stacked on the pallet. Palletized ganged containers may then be efficiently transported using trucks and railway. Fork lifts may be efficiently be used at the point of loading and unloading of palletized containers. 
         [0003]    It is an economic and practical necessity that bundling ganged containers onto a pallet be as easily and inexpensively achieved as possible. One solution to this requirement is to wrap or bundle the ganged containers in long strips or ribbons of plastic films. This is widely regarded as a desirable solution since plastic film is strong, inexpensive, easily applied to pallets bearing ganged containers, and easily removed from the pallets. 
         [0004]    Plastic films suitable for wrapping ganged containers are available in large rolls, wherein the width of the web of film is much greater than is practical with respect to handling for purposes of wrapping individual pallets and the ganged containers stacked thereon. It then becomes desirable to slit a web of plastic film into two, three or even more distinct ribbons. Each ribbon may be easily applied to one pallet and its ganged containers. When the supply roll of plastic film is slit into a number of ribbons, an equal number of pallets may be prepared for shipment simultaneously. This promotes an economy in that commercial firms which bundle pallets may enjoy minimized costs of the film itself by purchasing a relatively lesser number of relatively large rolls of plastic film, then slitting or cutting these large rolls to desired width in their facilities. Also, the rate of production of prepared pallets may be maximized by the practice of using plural slit ribbon simultaneously in the preparation of an equal number of pallets. 
         [0005]    This approach has served the shipping needs of distributors of palletized goods well. However, there remains one aspect of handling films which remains troublesome and relatively expensive. That is, because films are strong and are utilized in very great quantities, the customarily used slitting apparatus experiences fast wear of conventional circular blades which actually slit the film. In some bundling facilities, these blades may require sharpening or more likely replacement on a frequent basis, for example on the order of once a day. Blade replacement entails two types of expenses. One is the cost of the blades themselves. Blades are typically circular steel discs having sharp edges. The other cost is that replacement is a labor intensive operation, partially because replacement is frequently needed, but also because each replacement operation requires considerable time. 
         [0006]    There exists within the bundling and shipping industry a need for reducing costs of blade renewal in plastic film slitting operations. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention addresses the above stated need in two ways. One way is to utilize blades more durable, thereby requiring less frequent servicing. This may be done by utilizing ceramic materials rather than steel or other metallic materials. For example, the blade may be made entirely or partially from a ceramic material. The latter option may include for example coating the cutting surfaces of a blade with a suitable ceramic, such as a glassy material or a metal carbide. The coated blade may be mostly steel, which enables much of the blade to be fabricated from a relatively inexpensive material compared to the hard material used at the cutting surfaces, using conventional and relatively inexpensive fabrication techniques. 
         [0008]    Even though utilization of hard materials for cutting surfaces extends the service life of cutting blades in slitting apparatus, it does not address the issue of the time consuming operation of replacing blades. The present invention sets forth improved slitting apparatus which expedites the process of replacing cutting blades. In this improvement, the slitting apparatus is formed with cutting blades and their associated drive elements such as motor, speed reduction gears, and rotatable shaft supporting the cutting blades, and preferably, a housing which encloses these elements, made movable between a deployed position and a service position. In the service position, the blades are more conveniently accessed, thereby greatly reducing the time required to replace the blades. This reduces direct labor to replace blades and also downtime of idled cutting apparatus. 
         [0009]    In one implementation of the invention, the slitting apparatus may comprise stationary elements which are mounted to a frame of a machine which handles the unslit and subsequently slit film material, and a relatively movable blade assembly. The stationary elements may include mounting feet and a housing serving as a stationary supporting structure for a cam system which may then displace the movable blade assembly relative to the mounting feet. The movable blade assembly is moved by the cam system between a deployed position enabling slitting operations, and a service position facilitating blade replacement. The cam system may be operated by a manual lever. 
         [0010]    It is an object of the invention to expedite and facilitate blade replacement in slitting apparatus having one or more rotatable slitting blades. 
         [0011]    Another object of the invention is to employ an uncomplicated manual system to move the blade assembly between deployed and service positions. 
         [0012]    A further object of the invention is to extend the service life of slitting blades. 
         [0013]    It is an object of the invention to provide improved elements and arrangements thereof by apparatus for the purposes described which is inexpensive, dependable, and fully effective in accomplishing its intended purposes. 
         [0014]    These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    Various objects, features, and attendant advantages of the present invention will become more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein: 
           [0016]      FIG. 1  is a diagrammatic, environmental perspective view of the invention. 
           [0017]      FIG. 2  is a diagrammatic perspective view of one of the two principal components of the novel slitting apparatus. 
           [0018]      FIG. 3  is an exploded perspective view of the two principal components of the novel slitting apparatus. 
           [0019]      FIG. 4  is a side view of the camshaft seen at the right of  FIG. 3 . 
           [0020]      FIG. 5  is a side detail view taken along line  5 - 5  of  FIG. 3 . 
           [0021]      FIG. 6  is a side detail view similar to  FIG. 5 , but depicted movable components shifted from their original positions shown in  FIG. 6 . 
           [0022]      FIG. 7  is a perspective detail view of a component seen in end view in  FIG. 8 . 
           [0023]      FIG. 8  is an end view of the novel slitting apparatus of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    The overall purpose of the invention is diagrammatically illustrated in  FIG. 1 , wherein three pallets  2 ,  4 ,  6  each stacked with goods  8  are in the process of being wrapped or bundled so that each pallet  2 ,  4 , or  6  and its associated goods  8  will be capable of being maneuvered and transported as a unit. Wrapping uses a thin web such as a plastic film  10  which is stored on a large supply roll  12 . Plastic film  10  is unreeled from the supply roll  12 , moved past a slitting apparatus  100  which slits the plastic film  10  into three separate ribbons  14 ,  16 ,  18 . Each ribbon  14 ,  16 , or  18  is of width less than the width of the plastic film  10 , and is used to wrap one pallet  2 ,  4 , or  6 . 
         [0025]    Because  FIG. 1  is diagrammatic or symbolically representational, the apparatus shown therein is not literally rendered. Also, some necessary conventional apparatus is omitted from  FIG. 1 .  FIG. 1  is only intended to place the novel slitting apparatus  100  into understandable context for the reader. The slitting apparatus  100  is solidly mounted to a solid member of the plastic film handling apparatus (not shown) which is used to store and dispense the plastic film  10 , and is oriented to slit the plastic film  10  along its length as the plastic film  10  passes by the slitting apparatus  100 . An example of plastic film handling apparatus with which the slitting apparatus  100  may be used is KHS Innopack Kisters SP Basic Shrink Packer, KHS Filing and Packaging, KHS GmbH Juchostr. 20 D-44143 Dortmund, Germany. 
         [0026]    Referring now to  FIGS. 2 and 3 , the slitting apparatus  100  comprises two principal mutually movable members. One of these members is a stationary base member  102  ( FIG. 2 ), so called because it is solidly fixed such as by bolting to the plastic film handling apparatus. The other member is a blade assembly  104  ( FIG. 3 ) which is movable between a deployed or slitting position, further explained hereinafter, in which the blades of the blade assembly contact and slit passing plastic film  10 , and a retracted or service position, which is selected when renewing or otherwise servicing the blades. The stationary member  102  has two functions. One is to provide structural support to the blade assembly  104  so that the blade assembly  104  may be securely mounted on the plastic film handling apparatus. The other is to provide motive elements to move the blade assembly  104  between the slitting position and the service position. 
         [0027]    The base member  102  need not be of significant depth. Illustratively, it may comprise a structural panel or web  106 , two depending mounting feet  108 ,  110 , and sufficient structure such as trunnion bearing elements (not shown) to rotatably support a camshaft  112  on the structural web  106 . The camshaft  112  bears a cam lobe  116  and a lever  118  which serves as a handle for rotating the camshaft  112 . As will be explained hereinafter, the camshaft  112  is actuated by the lever to effect movement of the blade assembly  104  between the slitting position and the service position. 
         [0028]    Design of the base member  102  depends upon the type of plastic film handling apparatus in use, proximity and orientation of a suitable rugged surface to which the mounting feet  108 ,  110  may be bolted or otherwise fastened, and is adapted thereto. The mounting feet  108 ,  110  may have bolt holes  114  through which mounting bolts (not shown) may be passed when mounting the base member  102  to the plastic film handling apparatus. 
         [0029]    Referring specifically to  FIG. 3 , the blade assembly  104  may comprise a blade housing  120  which both encloses and supports moving parts of the blade assembly  104 . These moving parts may include a blade shaft  122  which may be journaled in an end wall  124  of the blade housing, or alternatively, held by trunnion bearings (not shown) or rotatably supported within the blade housing  120  in any other suitable way. The blade shaft  122  may comprise a blade retaining element for securing a removable blade to the blade shaft  122  (details of mounting of a blade will be described hereinafter). An electric motor  126  is disposed to rotate the blade shaft  122 . Preferably, the electric motor  126  is an AC motor operable on an AC supply circuit, and comprises a step-down gearset  128  which is interposed between the electric motor  126  and the blade shaft  122  and is disposed to rotate the blade shaft  122  at a rotation speed lower than that of the AC motor  126 . The slitting apparatus  100  will be understood to include necessary electric circuitry (not shown) necessary to operate the AC motor  126 . 
         [0030]    The blade housing  120  is incompletely depicted in that an upper wall which closes the interior of the blade housing  120  from above as seen in  FIG. 3  and a front wall which partially closes the interior of the blade housing  120  from the front are omitted in the view of  FIG. 3 . Preferably, the omitted walls would be provided to enclose the AC motor  126 , the step-down gearset  128 , and the blade shaft  122 , sufficiently to prevent direct manual contact with the AC motor  126  and the step-down gearset  128  from outside the blade housing  120 . The blades must necessarily be exposed in order to be able to engage and slit the plastic film  10  as the latter passes by the former. The outer circumference of the blades is indicated by broken lines  130  in  FIG. 3 . 
         [0031]    Although not fully visible in  FIG. 3 , a plurality of blades may be removably mounted to the blade shaft  122 . In the embodiment illustrated herein, two blades spaced apart from one another along the blade shaft  122  are provided, which enables the slitting apparatus  100  to slit the plastic film  10  into three separate ribbons  14 ,  16 ,  18 , as seen in  FIG. 1 . To this end, the blade shaft  122  comprises blade retaining elements in numbers corresponding to the number of blades intended to be used. Of course, the slitting apparatus  100  may be provided with a greater number of blade retaining elements than blades in active service, if desired (this option is not shown). 
         [0032]    Referring momentarily to  FIG. 4 , the nature of the blades and the blade retaining elements will be described. The blade shaft  122  at each end may terminate in a circular flange  132  and a threaded stub  134 . A blade  136  comprising a hub  138  through which passes a central hole  140  and from which projects a circular disc  142  having a sharp circumferential edge  144  may be slipped over the threaded stub  134 . Preferably, the central hole  140  is of dimensions and configuration enabling the stub  134  of the blade shaft  122  to be passed through the central hole  140  in close cooperation therewith. Thus mounted on the blade shaft  122 , the blade  136  may be secured in place with suitable fasteners, such as a flat washer  146 , a lock washer  148 , and a nut  150 . Of course, other arrangements may be used, such as a stub of the same diameter as the rest of the blade shaft, bearing a threaded hole for receiving a bolt in place of the nut  150  (this option is not shown). 
         [0033]    Although the entire blade  136  may be fabricated entirely from ceramic materials, it may also be fabricated from a less expensive material such as steel, provided that the cutting surface  152  is fabricated from a ceramic material. Ceramic materials may include silica, metal oxides, silicon carbide, a metallic carbide such as tungsten carbide or titanium carbide, or other known hard materials such as cubic boron nitride, polycrystalline diamond, and others, or any combination of these. At a minimum, the point or edge  144  and nearby surfaces  154 ,  156  will be coated with the ceramic material. 
         [0034]    As has been mentioned previously, the blade assembly  104  is movable between a slitting position and a service position. The base member  102  cooperates with the blade assembly  104  to achieve this transition. The blade assembly  104  may comprise two smooth walled fingers  158 ,  160  which may be received within corresponding holes  162 ,  164  formed in the web  106  of the base member  102 . The holes  162 ,  164  constrain the blade assembly to move only axially with respect to the fingers  158 ,  160  and the holes  162 ,  164 , these components thus serving as guide and support elements for holding the blade assembly  104  selectively in the slitting position and the service position. In the slitting position, the blade  136  mounted to the blade shaft  122  projects from the blade housing  120  sufficiently to slit a web passing thereby, as seen in  FIG. 3 . In the service position, the blade assembly  104  is displaced relative to the stationary base member  120  from the slitting position, wherein the guide and support elements are disposed to constrain the blade assembly  104  to occupy only the slitting position and the service position and to move therebetween. 
         [0035]    It will be appreciated that the guide and support elements constrain the blade assembly  104  to the path of travel described above, but do not themselves actually move the blade assembly  104  between the slitting and service positions. The blade assembly  104  is moved between the slitting and service positions by the camshaft  112  and cam lobe  116  when the lever  118  is manually moved. 
         [0036]    This is illustrated in  FIGS. 5 and 6 .  FIG. 5  illustrates the service position and first and second positions of the lever  118 , which positions correspond to the service position ( FIG. 5 ) and the slitting position ( FIG. 6 ) of the blade assembly  104 . The lever  118  has been moved such that cam lobe  116  causes the blade assembly  104  to be drawn relatively near the web  106 . Proximity of the blade assembly  104  to the web  106  is indicated by a gap  170 . The cam lobe  116  engages the inner surface of an elongated opening  166  of a member serving as a yoke  168  fixed solidly to the housing  120  of the blade assembly  104 . When the lever  118  is moved to the position shown in  FIG. 6 , the cam lobe  116  acts on the yoke  168  to move the blade assembly  104  further from the web  106  than as seen in  FIG. 5 . This displacement of the blade assembly  104  is apparent from the magnitude of the gap  172  seen in  FIG. 6 . 
         [0037]    The camshaft  112 , its associated handle  118  and cam lobe  116 , and the yoke  168  may be regarded as a manual shifting element disposed to move the blade assembly  104  between the slitting position and the service position. 
         [0038]    It should be noted that the lever  118  is sufficiently long so as to project from the slitting apparatus  100  sufficiently to be exposed to manual access even should the slitting apparatus  100  be provided with a housing (not shown) which fully encloses the components of the base member  102  other than the lever  118 . 
         [0039]      FIG. 7  shows a tension roller assembly  180  which may be provided to assure that the web  10  is under appropriate tension as it contacts the blades, the latter represented as circumference  130  (see  FIG. 3 ). The tension roller assembly  180  may also provide a safety function, as further described hereinafter. The tension roller assembly  180  may comprise a tension shaft  182  which may be supported for example by being journaled within holes formed in the end walls such as the end wall  124  of the blade housing  120 . A pair of circular bearings  184 A,  184 B are rotatably mounted for free rotation on the tension shaft  180 , and if not constrained, may move axially along the tension shaft  180 . During assembly of the slitting apparatus  100 , the pair of circular bearings  184 A,  184 B are moved axially along the tension shaft  182  into sandwiching relationship about one blade represented by the blade circumference  130 , and are locked into place leaving a gap  185  for receiving the blade. Spacing of the circular bearings  184 A,  184 B to the blade is fairly close, but sufficiently spaced apart so as to enable unimpeded rotation of the blade. One pair of circular bearings  184 A,  184 B is provided for each blade. Each pair of circular bearings such as the pair of circular bearings  184 A,  184 B is surrounded by a pair of stops such as stops  186 A,  186 B. Each stop may comprise a disc which is movable axially along the tension shaft  182  and may have a setscrew such as the setscrews  188 A,  188 B, which when tightened locks its associated disc to the tension shaft  182 . This maintains the circular bearings  184 A,  184 B in a selected position surrounding their associated blade which is received in close proximity thereto within a gap  187 . 
         [0040]      FIG. 7  depicts a second set of circular bearings  190 A,  190 B and stops  192 A,  192 B each having a setscrew  194 A or  194 B, each of which may be the structural and functional equivalent of their similarly named counterparts described above. 
         [0041]      FIG. 8  illustrates the function of the tension roller assembly  180 , which is mounted to the blade housing  120  in any suitable way, such as journaling as mentioned above. It will be seen that the blade housing  120  may have an access opening  196  which opens the blade housing  120 , thereby exposing the blades to access. The tension roller assembly  180  may be disposed proximate the blade shaft  122 . The tension roller assembly  180  may be located between the cutting blades and the access opening  196 , thereby obstructing the blades to direct access through the access opening  196 . 
         [0042]    It will be seen that the web  10  is maintained under tension even as it passes by the blades (again, represented by blade circumference  130 ). This holds the web  10  in an optimum position as the web  10  moves in the direction of the arrows A so that cutting effort imposed on the blades is minimized. 
         [0043]    Thus the tension roller assembly  180  serves not only to hold the web  10  in an appropriate and effective position for slitting, but also provides a measure of safety in obstructing direct access to the blades. 
         [0044]    Although described as journaled within the blade housing  1240 , the tension roller assembly  180  could be supported on a bracket (not shown), and further, the bracket may be adjustable in position so as to adjust tension imposed on the web  10 . 
         [0045]    While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is to be understood that the present invention is not to be limited to the disclosed arrangements, but is intended to cover various arrangements which are included within the spirit and scope of the broadest possible interpretation of the appended claims so as to encompass all modifications and equivalent arrangements which are possible