Abstract:
The apparatus and method disclosed is for removing labels from surfaces, especially from pharmaceutical vials. Each vial is brought into a travel path where it is moved forward by a linear driver. The vial is first pushed through a circular array of slitter blades to create a series of longitudinal slits in the label. The vial is next pushed through a circular array of scraper blades that remove the label segments between each pair of slits. The label segment residue is discarded through a vacuum system.

Description:
FIELD OF THE INVENTION 
     The present invention relates to the field of apparatus and methods for removing labels from objects having a hard surface, and more particularly to removing labels from vials. 
     BACKGROUND OF THE INVENTION 
     Containers for pharmaceutical liquids are generally termed vials, covering a capacity range of from approximately 30 ml to approximately 1000 ml. Vials are typically configured of molded glass with a substantially cylindrical body portion and a somewhat narrower neck, the opening at the top of the neck being sealed with an elastomeric membrane held by a metallic band. At the microscopic level, molded glass often has flat spots and indentations. A printed label is applied to the vial with an adhesive. The label is typically a plastic film, and the adhesive is typically an acrylic polymer with strong adhesion characteristics. Certain vials are intended to be suspended from a support pole in a medical environment to dispense the vial&#39;s contents by force of gravity. In this instance, a band is adhered to the vial over the label with a suspension loop connected to the band but not glued. Whereas the loop and band must securely support the weight of the vial and contents, the band must be adhered to the label and the label to the vial with an aggressive adhesive. Occasionally, it is necessary to remove labels, e.g. if an error in information or contents makes the existing label inaccurate. In order to remove the printed information label, it would be necessary to also remove the band and suspension loop. 
     The field of apparatus and methods for removing labels from rigid containers is represented by U.S. Pat. No. 4,122,734 for a Label Stripping Machine, U.S. Pat. No. 5,152,865 for a Method For Clean Removing Labels From Containers, and U.S. Pat. No. 5,651,846 for Method And Apparatus For Removing The Printed Layer Of Labels From Semirigid Containers. The degree of adhesion of the labels to vials discussed above has been determined to be beyond the ability of the apparatus and methods of these patents. Therefore, a need exists for an apparatus and method for removing labels that are adhered to vials or other objects with hard surfaces with a particularly aggressive adhesive. 
     SUMMARY OF THE INVENTION 
     The invention provides an apparatus and method for removing labels that are adhered aggressively to vials or other hard surface objects. The invention apparatus has an array of slitter blades that are applied to cut parallel slits through the label, forming label strips. In a second stage, an array of scraper blades lift the label strips formed between the slits from the surface. Both the slitter blades and the scraper blades are pivotally mounted and biased to press on the surface of the vial or other object being moved thereby. A vacuum device is provided for removing the residual debris from the label scraping operation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is best understood in conjunction with the accompanying drawing figures in which like elements are identified by similar reference numerals and wherein: 
         FIG. 1  is a front elevation view of a typical vial with a printed information label adhered thereto and a connected hanging loop band. 
         FIG. 2  is a top plan view of one embodiment of the invention apparatus. 
         FIG. 3  is an axial view of slitter blades mounted in a circular array. 
         FIG. 3A  is a side elevation view of a pair of opposed slitter blades as seen in the array of  FIG. 3 . 
         FIG. 4  is an axial view of scraper blades mounted in a circular array. 
         FIG. 4A  is a side elevation view of a pair of opposed scraper blades as seen in the array of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIG. 1 , a typical object with a hard surface, e.g. a glass vial  10 , is shown in front elevation view. A label  12  is mounted to the outer surface of vial  10  by a relatively aggressive adhesive. A band  16  with a connected hanging loop  18  is mounted to the outer surface of label  12  by a relatively aggressive adhesive in a manner for supporting vial  10  from an intravenous pole, or the like. Label  12  is generally formed of plastic film sheet material. Band  16  is typically formed of a tough, resilient plastic resin. Band  16  and label  12  are adhered to one another and to vial  10  with relatively aggressive adhesives, e.g. acrylic polymer adhesive, to provide secure support when vial  10  is filled with a valuable liquid pharmaceutical and hanging from a intravenous pole. 
     Referring now to  FIG. 2 , a preferred embodiment of the invention apparatus for removing labels, especially plastic film labels and bands aggressively adhered to the vials, is shown in top plan view. A conveyor  22 , or similar supply mechanism, is mounted to deliver a series of labeled vials  10  in the direction indicated by arrow A to a set of guide rails  30 , guide rails  30  being depicted with hatch lines for clarity. Whereas the guide rails are depicted in horizontal orientation, it is understood that vertical orientation with vials  10  being moved upward would function equally well. Similarly, conveyor  22  may be in an alternate orientation. Vials  10  are preferably oriented with their caps facing to the right as illustrated for travel in the direction of the travel path indicated by arrow B. A linear actuator  26 , e.g. a pneumatic cylinder, is mounted at an entry end of the travel path as delineated by guide rails  30 . Guide rails  30  are shown as segmented to permit placement of operating mechanisms intermediate thereof. A labeled vial  10   a  has been positioned on guide rails  30  and been moved in the direction indicated by arrow B there along. Vial  10   a  is illustrated as positioned partially through a slitter array  34 . Slitter array  34  is preferably formed as a radial array of slitter blades to circumferentially contact the periphery of vial  10   a . It is understood that application of the invention to remove adhered labels from objects having a planar surface would involve a planar slitter array. A second vial  10   b  is seen in a position beyond slitter array  34  and supported on a further section of guide rails  30 . Label  12   b , adhered to vial  10   b , is shown as having been divided by a series of slits that were created by passing through slitter array  34 . 
     Referring further to  FIG. 2 , vial  10   c  continues to move in the direction of arrow B to pass through a scraper array  44 . Scraper array  44  is preferably formed as a radially array of scraper blades to circumferentially contact the periphery of vial  10   c . When labels are to be removed from objects with a planar surface the array of scraper blades will also be planar. The invention provides one scraper blade in scraper array  44  for each slitter blade in slitter array  34  with the slitter blades and the scraper blades circumferentially interspersed. This interspersed arrangement allows each scraper blade to contact and lift a section of label between adjacent slits. The sections of lifted label, indicated by numeral  12   c , are removed by means of a vacuum with inlet nozzles  48   a ,  48   b . Alternate arrangements for label segment removal devices, e.g. an annular vacuum ring, are within the scope of the present invention. Subsequent to passing through scraper array  44  and vacuum nozzles  48   a ,  48   b , vial  10   d  is substantially clean and in position at the exit of the travel path to be discharged for further processing. Any additional label or adhesive residue may be removed in a subsequent operation. 
     Referring now to  FIGS. 3 and 3A , slitter array  34  is seen in end view in the direction indicated by line  3 - 3  of  FIG. 2 . A plurality of slitter blades  36 , according to the preferred embodiment, reside in a circular array sized to press against the outer diameter of a vial  10   a  (see  FIG. 2 ). Each slitter blade  36  is oriented along a radius of the circle and spaced from each other at the innermost diameter by a distance S. Distance S is preferably between 2.0 mm (0.080 inch) and 10.0 mm (0.394 inch), most preferably approximately 8.0 mm (0.315 inch).  FIG. 3A  depicts a pair of diametrically opposed slitter blades  36 , e.g. slitter blades  36  seen at the top and bottom of the array of  FIG. 3 . Slitter blades  36  are each formed with a cutting edge  38 , cutting edge  38  facing toward the center of the circular array. Slitter blades  36  are each mounted on a pivot  40  and are biased to pivot in the direction indicated by arrow D by a spring  42  or other biasing means. Therefore, slitter blades  36  will press against and cut through a label on the surface of the vial being processed. As shown in  FIG. 2 , slitter array  34  creates a series of slits through label  12   b  that are oriented parallel to the axis of vial  10   b  and separated from one another. An alternate configuration for the slitter blades illustrated is a rotatable circular knife blade. 
     Referring now to  FIGS. 4 and 4A , scraper array  44  is seen in end view in the direction indicated by line  4 - 4  of  FIG. 2 . A plurality of scraper blades  46  reside in a circular array having a similar inside diameter as the array of  FIG. 3 , i.e. a diameter sized to press against the outer diameter of a vial  10   c  (see  FIG. 2 ). The number of scraper blades  46  is equal to the number of slitter blades  36  of  FIG. 3 . Each scraper blade is oriented along a radius of the circle and positioned between adjacent pairs of slitter blades  36  ( FIG. 3 ).  FIG. 4A  depicts a pair of diametrically opposed scraper blades  46 . Scraper blades  46  are each formed with a scraping edge  48 , each scraping edge  48  being aligned tangential to the outer surface of vial  10   c  ( FIG. 2 ). Scraping edge  48  of each scraper blade  46  is generally in the form of a chisel edge, i.e. tapered on one side only, with a cutting angle T of approximately 30°. As shown, scraper blade  46  is oriented with the flat side closer to the vial and the angled side farther from the vial. In a further embodiment, the chisel edge of scraper blades may be in arcuate form to approximately conform to the curvature of the vial being processed. Scraper blades  46  are each mounted on a pivot  50  and are biased to move pivotally in the direction indicated by arrows E by a spring  52  or other biasing means to press against the vial surface and lift the label segments therefrom. Therefore, after slitter array  34  (see  FIG. 2 ) creates a series of slits through label  12   b , scraper array  44  scrapes the portions of label  12   b  from vial  10   c  to be discarded as label scraps  12   c.    
     Vials are typically made of molded glass and have an irregular surface on the microscopic level, including flat spots and depressions. In order to maximize the operational life of blades in contact with the irregular glass surface of vials, slitter blades  36  and scraper blades  46  are formed of a tough, durable steel alloy containing no less than 8.0% vanadium. 
     Therefore, the method for removing labels according to the present invention involves the steps of: 
     1. passing a series of vials along a travel path through a circular array of radially oriented slitter blades that are biased into contact with the vial to create a number of slits through the labels parallel to the travel path; 
     2. passing the vials further along the travel path through a circular array of radially oriented scraper blades that are biased into contact with the vial to scrape the label segments residing between the slits from the vial surface; and 
     3. removing the label segments scraped from the vials with a vacuum and discarding the label segments. 
     Having removed the incorrect labels from the vials, the vials may be further cleaned as necessary and a correct label applied. Therefore, the apparatus and method described herein has effectively and efficiently salvaged the vials and the contents therein after a labeling error. 
     Whereas the invention described herein is primarily directed to an apparatus and method for removing labels from vials, it will be readily understood to similarly apply to labels on a planar or other shaped object surface. It is therefore believed to be within the scope of the invention to apply the apparatus and method disclosed to objects of various geometry for the removal of labels. 
     While the description above discloses a preferred embodiment of the present invention, it is contemplated that numerous variations and modifications of the invention are possible and are considered to be within the scope of the claims that follow.