Abstract:
A unit for applying labels at predefined designated locations along the length of a moving web of material. The unit includes one or more label discharge mechanisms which remove labels from a carrier backing for discharge to a defined placement zone. The label discharge mechanisms are actuatable in response to commands from a controller to effect placement of the labels at designated locations along the length of the web. The controller initiates actuation of the label discharge mechanisms according to a variable timing sequence which is a function of the rate of travel of the moving web to which the label is applied such that label application takes place as the designated location to be labeled passes through the placement zone. The unit is adjustable to apply labels to webs traveling at different angles.

Description:
This is a division of application Ser. No. 09/522,975 filed on Mar. 10, 2000 now U.S. Pat. No. 6,412,535. 

   TECHNICAL FIELD 
   The present invention relates to a unit for applying labels to a surface, and more particularly to a unit for applying labels at designated locations along the length of a moving web of material so as to mark such locations. 
   BACKGROUND OF THE INVENTION 
   The production of a number of materials such as paper, films, textiles, and floor coverings, is carried out by forming such materials as elongated webs of substantial length which are thereafter segmented by cutting to yield lengths which are usable by the customer. While the character of the material along the length of the web may appear to be uniform, in many instances there will be variations along the length of such webs. These variations may arise for example in the form of slightly modified construction techniques which are intentionally introduced and/or in the form of either instantaneous or running defects within the material forming the web. 
   As will be appreciated by those of skill in the art, following production of the web material, the web will typically undergo an inspection process to identify the location and nature of variations along its length. Such inspection may be performed either manually and/or through use of automated equipment. One such automated system for the identification of variations along the length of a material web is believed to be available from Elbit Vision Systems which is believed to have a place of business in Tel Aviv, Israel. 
   Based upon the inspection of the web material produced, a listing of the variations along the length of the web may be generated. Such a listing is commonly referred to as a defect map. The map typically identifies the location, duration, and nature of the variations identified along the length of the material web. This data is typically stored in a retrievable registry format referred to by those of skill in the art as a defect album. 
   While the web materials which are formed are generally of extremely long length, the ultimate users of such materials oftentimes require lengths which are much shorter than the lengths formed during the production process. Moreover, the quality standards for different users may vary such that certain defects will be permissible to some users while being unacceptable to others. In recognition of the need to segment the web of material to yield shorter lengths of character and quantity as may be required by the various users, such production webs typically undergo what is referred to as a debatching process. During the debatching process the web is segmented and allocated for delivery to various customers. Such segmentation and allocation is typically carried out using the information from the map of variations along the length of the material web so as to deliver material which conforms to the product specifications of the various purchasers. The segmented lengths of material are typically placed into a roll form for delivery to the user. 
   As will be appreciated, in the event that the material being formed is a textile, the segmented webs of textile material which are shipped to the user may be subject to further cutting to yield panels of material which are thereafter incorporated into garments or other final structures being produced. In order to assist the users of such materials in efficiently conducting such further cutting, it is known to place removable labels at locations along the length of the material to identify the location and duration of any anomaly or other variation as may be present along the length of the material web. Such labels are typically placed in overhanging relation to the edge of the material web such that a portion of the label will protrude outwardly from the end of the roll of material shipped to the user. By way of example only, in the event that there is a running defect along some lengths of the material provided to the user, labels may be placed at the origin and the termination of the length of material affected by such running defect so as to alert the user of the material to the presence of such defect thereby permitting him or her to cut around the defect or to otherwise adjust production accordingly. 
   Although the use of labels to identify the location and duration of variations along the length of a material web is generally known, the actual placement of such labels at the proper location has heretofore been difficult to achieve. Such difficulty has typically arisen as a result of variations in the speed with which the material web travels during the debatching process. Moreover, the label application devices which have been previously available have generally been large, cumbersome units which are not versatile in assuming different operating configurations as may be required based on the layout and availability of space along the path of travel for the material web to be marked. 
   SUMMARY OF THE INVENTION 
   It is a general object of the present invention to provide an application unit for the precise disposition of labels at designated locations along the length of a web of material when such web of material is moving at variable rates of speed. 
   It is a further object of the present invention to provide an application unit for the disposition of labels at designated locations along the length of a moving web of material which application unit incorporates angular adjustment for placement along inclined portions of the conveyance path for such web of material. 
   According to a potentially preferred feature of the present invention, the application unit includes a label discharge mechanism which is operatively connected to a controller which actuates the label discharge mechanism according to a variable timing sequence as a function of the rate of travel of the web of material. 
   According to a further feature of the present invention, the application unit for applying labels at designated locations along the length of a moving web of material utilizes an articulating reversible vacuum grid as the discharge mechanism to place the label at a designated location. 
   According to a further feature of the present invention, the application unit preferably includes dual label discharge mechanisms each of which is independently operable from the other. 
   According to a further feature of the present invention, the application unit includes a label placement verification sensor to confirm proper placement and adhesion of the label. 
   According to one aspect of the present invention an application unit for applying labels at designated locations along the length of a moving web of material is provided. The application unit includes one or more label discharge mechanisms in the form of reversible vacuum grids which accept labels from a carrier backing for placement along the length of the moving material web. The label discharge mechanisms are actuatable in response to commands from a controller to place labels at designated locations. The controller initiates actuation of the label discharge mechanisms according to a variable timing sequence which is a function of the rate of travel of the moving web to which the label is applied. The variable timing sequence is calculated based upon the time lag between actuation of the label discharge mechanism and completion of the label placement and the amount of material which is transmitted past the label discharge mechanism during such time lag given the rate of travel of the material web. Such rate variable actuation thereby permits placement of the label at the precise location desired regardless of the actual rate of web travel. 
   Accordingly, the present invention provides useful advantages and alternatives over the prior art. 
   While the invention has been generally described and will hereafter be illustrated and more fully described in connection with certain potentially preferred embodiments, it is to be understood that the invention is in no way limited to such illustrated and described embodiments. To the contrary, it is contemplated that persons of skill in the art may make modifications to such preferred embodiments within the scope of the invention. Thus it is the intention of the applicants to cover all such alternatives and modifications as may fall within the true spirit and scope of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An embodiment of the present invention is described below, by way of example only, with reference to the accompanying drawings in which: 
       FIG. 1  is a block diagram of a web debatching arrangement in which the label application unit according to the present invention may be utilized; 
       FIG. 2  is a front view of a label application unit according to the present invention; 
       FIGS. 3A-3D  illustrate the operation of a label discharge mechanism for use in a label application unit according to the present invention; 
       FIG. 4  is a rear view of the label application unit according to the present invention; and 
       FIG. 5  illustrates the label application unit of  FIG. 1  rotated approximately 90° to accommodate a substantially vertical web conveyance path. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Turning now to the figures, wherein like elements are designated by like reference characters throughout the various views, in  FIG. 1  there is illustrated in block diagram form an arrangement of components for a debatching and label application process. According to the illustrated arrangement, a defect album  12  comprising a listing of the location, duration, and nature of defects or other variations along the length of the material web to undergo debatching is provided. The defect album is operatively connected via an appropriate communications link  14  to a debatch programmable logic controller  16  as is well known to those of skill in the art. The debatch programmable logic controller  16  is operatively connected via an appropriate communications link  18  to the debatching unit  20  which typically includes a yardage clock  21  which monitors the movement of the material through the debatching unit  20 . The debatching unit  20  receives instructions from the debatch programmable logic controller  16  regarding the discharge and segmentation of the material web based upon the location and nature of defects within the web of material as listed on the defect album  12 . Through use of the yardage clock  21  the debatching unit  20  correlates the instructions from the debatch programmable logic controller  16  to the actual position of the web of material within the debatching unit  20  so as to perform segmentation at the proper location. As will be appreciated, the instructions from the debatch programmable logic controller  16  preferably incorporate an optimization function to optimize the use of available material within the web. Such optimization programs are well known to those of skill in the art and constitute no portion of the invention herein. 
   As illustrated, the debatch programmable logic controller  16  preferably includes a data link  22  to a label applicator programmable logic controller  24 . The applicator programmable logic controller  24  is thereby provided with data regarding the location along the length of the web where labels are to be applied. One potentially preferred unit as may be used for the applicator programmable logic controller  24  is a model IC693 UDR005-P1 series 90 micro PLC manufactured by the General Electric Company having a place of business in Fairfield Conn., USA. 
   As will be appreciated, The debatching unit  20  may operate at different speeds during the debatching process. Thus, in order to provide the applicator programmable logic controller  24  with sufficient data to identify the speed of the web and the position of locations to be marked along the web of material, a position speed sensor  26  is preferably utilized. By way of example only, the position speed sensor  26  may be a rotational meter which rides on the web to be marked as will be well known to those of skill in the art. As the rate of dispatch of the web from the debatcher varies, the position speed sensor communicates the instantaneous rate to the applicator programmable logic controller  24  via a communications link  28 . Thus, the applicator programmable logic controller  24  can at all times establish the position of any point along the length of the web to be marked. The applicator programmable logic controller is thereby able to actuate the label applicator  30  to place labels at locations identified by the defect album  12 . As illustrated, the operation of the label applicator  30  may be monitored at an operator display terminal  29 . 
   Due to the fact that the label application constitutes the physical process of placing a label on the web to be marked, some finite period of time hereafter referred to as lag time exists between the time that the applicator programmable logic controller actuates the label applicator  30  and the time that the label application process is completed. In the event that the label applicator  30  utilizes a forced air discharge of the label as described further hereinafter, it is believed that the lag time will be about 15 to 20 milliseconds. While such lag time is relatively short, it must nonetheless be accounted for in order to achieve precision in label placement. While the lag time has no affect in the labeling of a stationery web and will have little affect on labeling of a slow moving web, the lag time may become relevant to the precision of label placement in those applications where the web is traveling at a very high rate of speed. 
   According to the preferred embodiment of the present invention, the applicator programmable logic controller  24  accounts for the lag time and the resultant impact on label placement through the calculated early actuation of the label application unit  30  according to a speed variable actuation timing sequence. That is, the timing for the actuation of label placement is a function of the rate of travel of the web to be marked. Accordingly, when the web to be marked is moving quickly, the label applicator will be actuated to begin label placement before the location to be marked reaches the application zone for the label application unit  30 . The faster the web is moving, the more space is allotted between the position to be marked in the label application zone. According to a preferred form of the invention, this distance will be substantially equivalent to the distance traveled by the web during the lag time of the label application unit  30 . Thus, through calculated premature actuation based upon instantaneous rate of web travel, any change to such rate may be accounted for. 
   In  FIG. 2 , there is illustrated a side view of a potentially preferred embodiment of the label application unit  30  according to the present invention. As illustrated, according to the potentially preferred embodiment of the present invention, the label application unit  30  includes two substantially identical systems mounted in mirror image orientation to one another on a support frame  31  for application of label elements  32  to a moving web  34 . However, it is likewise contemplated that the label application unit  30  may incorporate either a larger or smaller number of systems. Moreover, in the event that two or more application systems are incorporated, it is contemplated that such systems may be operated either independently or in conjunction with one another. As will be appreciated, the applicator programmable logic controller  24  may be mounted on the support frame  31  or may be separate. 
   As illustrated, each of the application systems preferably includes a spool device  36  for the storage and disposition of a tape roll  38 . The tape roll  38  is formed from windings of a carrier tape  40 . As illustrated, the label elements  32  are disposed on one side of the carrier tape  40  so as to be on the exterior of the tape roll  38  as the tape roll  38  is unwound. The label elements  32  are preferably held in place at regular spacing along the length of the carrier tape  40  by a releasable adhesive. 
   According to a potentially preferred practice, the label elements  32  are of a substantially rectangular configuration having a length dimension of about 2 inches and a width dimension of about 1 inch. The releasable adhesive is preferably patterned across the underside of the label elements  32  such that the region along the length dimension adjacent either end of the label elements is substantially free of adhesive. In the event that the label element is 2 inches in length, the adhesive free region preferably extends about {fraction (5/16)} inches inwardly from either end such that adhesive covers the remaining 1 and ⅜ inches across the interior of the label. The use of such patterned label elements  32  permits the adhesive free portion to protrude away from the edge of the marked web of material thereby reducing the possibility for undesired adhesion to a foreign surface. The use of label elements  32  having no adhesive on either end provides the added advantage of eliminating the potential for operator error when loading the tape roll  38  onto the spool device  36 . 
   In the illustrated and potentially preferred embodiment, the carrier tape  40  is withdrawn from the tape roll  38  by the application of a pulling force initiated by a stepper motor  42  which is periodically activated by the applicator programmable logic controller  24  as required to feed discrete label elements  32  to a label discharge device  44  for application of the label  32  to the moving web  34 . The applicator programmable logic controller  24  may immediately or after a delay activate the stepper motor  42  after each label is applied thereby providing the label discharge mechanism  44  with a new label for subsequent application in a manner to be described further hereinafter. In operation, the stepper motor  42  will be activated immediately if the need to place the next label  32  is imminent, while a delay will be imposed if a label is not required for application for some predetermined period of time. 
   The pulling force applied by the stepper motor  42  is discontinued once the new label has been fed to the label discharge mechanism  44 . Termination of the stepper motor  42  is preferably based upon a signal provided to the applicator programmable logic controller  24  from an optical sensor  46  indicating that the label has been fed to the label discharge mechanism  44 . The carrier tape  40  is preferably taken up by a motor driven take-up spool  48  which is operable in conjunction with the stepper motor  42 . In the illustrated and potentialy preferred embodiment, a floating nip roll  43  is used to prevent slippage between the carrier tape  40  and the stepper motor  42 . The floating nip roll  43  is preferably held in place by a compressible cylinder support  45 . In the event that the carrier tape  40  should break and begin to accumulate around the stepper motor, the floating nip roll is forced back by the accumulating tape thereby compressing the cylinder support. Once such compression reaches a predetermined level, a limit switch is tripped thereby sending a fault signal to the operator display terminal  29  and terminating further operation of the stepper motor  42  until the carrier tape  40  is arranged properly. 
   One potentially preferred stepper motor  42  for use in the label applicator  30  according to the present invention is believed to be the model PK268-03A oriental 6 lead stepper motor which is believed to be available from General Controls Electronics, Inc., having a place of business in Elk Grove Village, Ill., USA. One potentially preferred take-up motor  48  is a model UTAM4-0101S Taiyo pneumatic piston motor. The optical sensor  46  is preferably a model D12EP6FP banner label photoelectric sensor in combination with a model PDIS46UM12 banner plastic fiber assembly which detects the presence or absence of a label element  32 . 
   The physical procedure for placement of individual label elements  32  onto the moving web  34  is illustrated in  FIGS. 3A-3D . As shown in  FIG. 3A , a carrier tape  40  carrying a plurality of discrete label elements is preferably conveyed around the nose of the take-off plate  50 . As best illustrated in  FIG. 3B , as the carrier tape  40  bends around the nose of the take-off plate  50  so as to reverse direction away from the label discharge mechanism  44 , the leading label element  32  tends to peel away from the carrier tape  40 . This peeling away phenomenon arises due to the fact that the adhesive which holds the label element  32  to the carrier tape  40  is of a releasable nature such that the shear forces applied between the label element  32  and the carrier tape  40  which arise as the carrier tape  40  is conveyed around the radius of curvature formed by the nose of the take-off plate  50  are sufficient to overcome the adhesive bond between the label element  32  and the carrier tape  40 . As will be appreciated, the releasable nature of the adhesive on the label element  32  is likewise useful in permitting the removal of the label element  32  from the material forming the moving web  34  at later stages of material processing. 
   As the leading label element  32  is peeled away from the carrier tape  40 , it will tend to continue in a path of travel generally parallel to the upper surface of the take-off plate  50 . According to the illustrated and potentially preferred embodiment of the present invention, this continued conveyance brings the label element  32  into contact with the underside of the label discharge mechanism  44  (FIG.  3 B). As shown, the angle of the label discharge mechanism  44  relative to the conveyed label element  32  is such that contact is assured between the label element  32  and the underside of the label discharge mechanism  44 . 
   The label discharge mechanism is preferably an articulating vacuum grid which includes a plurality of flexible feed lines  52  which are operatively connected to a vacuum pump (not shown) such as an M20G6-MN Piab vacuum generator. This vacuum pump is of such a nature that a vacuum may be pulled across the label discharge mechanism  44  at a level sufficient to hold a label element  32  in place against the underside of the discharge mechanism  44 . Thus, at the position as generally illustrated in  FIG. 3B , the label element  32  is prevented from falling by a combination of both its internal stiffness as well as the vacuum force applied through the label discharge mechanism  44 . 
   As illustrated in  FIG. 3C , the procedure of peeling the label element  32  away from the carrier tape  40  is preferably completed by swinging the label discharge mechanism  44  downwardly around a pivot point  54  so as to bring the label element  32  into a substantially parallel relation to the moving web  34 . As shown, the pivot point is preferably selected so as to move the underside of the label discharge mechanism away from the take-off plate  50  as such rotation takes place thereby effecting a corresponding lateral movement of the label element  32  away from the take-off plate  50  and carrier tape  40  carried thereon. Such outward movement avoids any possible interference between the label discharge mechanism  44  and the take-off plate  50  during subsequent label application. While the use of such an articulating label discharge mechanism is potentially preferred, it is likewise contemplated that a number of alternative embodiments and practices may also be utilized. By way of example only, and not limitation, it is contemplated that the label discharge mechanism  44  may be stationary and that the take-off plate  50  may be moveable in a substantially linear manner so as to bring the label element  32  into an underlying relation with such label discharge mechanism  44 . 
   Regardless of the mechanism which may be utilized to load the label element  32  onto the label discharge mechanism  44 , according to the preferred practice of the invention the label element  32  will ultimately assume an operative position some lateral distance from the take-off plate  50  and substantially parallel relative to the moving web  34  as illustrated in FIG.  3 C. Upon actuation by the applicator programmable logic controller, the vacuum across the discharge mechanism  44  is terminated and is replaced with a pressurized driving force in the form of compressed air communicated through the feed lines  52  so as to cause forcible dispatch of the retained label element  32  away from the label discharge mechanism  44  and onto the moving web  34 . In the illustrated and potentially preferred embodiment of the present invention this dispatch is achieved by blowing the label element  32  into place without the use of mechanical contact between the label discharge mechanism  44  and the moving web  34 . Such placement procedure is believed to have the advantage of accommodating webs of varying thickness without the need for adjustment of the label discharge mechanism  44 . As illustrated, the adhesive bearing surface of the label element  32  which was previously in contact with the carrier tape  40  is thereby placed into contact with the moving web  34  so as to hold the label element  32  in place on the web  34 . 
   As previously discussed, the actuation of this discharge procedure is initiated by the applicator programmable logic controller  24  before the location to be marked reaches the application zone directly opposing the label discharge mechanism  44 . The duration of such lead time is dependent upon the instantaneous speed of the moving web  34  and is calculated such that the location designated to receive the label element  32  will reach the position opposing the label discharge mechanism  44  as the placement of the label element  32  is completed. 
   In the event that another label is to be applied, once the placement of a label element  32  has been completed the label discharge mechanism  44  may immediately or after a delay return to a position as illustrated in  FIG. 3A  for acceptance of a new label element. Upon the label discharge mechanism  44  assuming the position for acceptance of a new label element, the stepper motor  42  is activated and commences to pull the carrier tape supporting the new label element  32  around the nose of the take-off plate  50  as shown in FIG.  3 B. As the label element  32  is being loaded onto the label discharge mechanism  44 , the optical sensor  46  monitors the extent of travel of the carrier tape  40  and label elements carried thereon. As previously indicated, the label elements  32  are of a nature such that the optical sensor  46  can readily detect their presence. In the illustrated and potentially preferred embodiment of the present invention, the optical sensor  46  is arranged along the length of the take-off plate  50  at a position such that during the loading of the leading label element  32  onto the label discharge mechanism  44  the trailing label element  32 ′ will travel past the optical sensor  46 . Once the trailing label element  32 ′ has passed the optical sensor  46 , the optical sensor  46  preferably sends a signal to terminate further movement of the carrier tape  40 . Thus, through selection of the location for the optical sensor  46 , movement of the carrier tape  40  may be terminated precisely when the label element  32 ′ reaches the appropriate position for subsequent loading onto the label discharge mechanism  44 . 
   As indicated previously, the adhesive as is utilized on the label elements  32  is preferably of a substantially releasable nature such that the label elements  32  may be peeled away from the carrier tape  40  as well as from the moving web  34 . In order to enhance the adhesion of such releasable adhesive, the label discharge mechanism  44  is preferably maintained in a heated condition at about 30 to 80 degrees Fahrenheit above ambient. 
   In the potentially preferred embodiment of the present invention, a placement sensor  56  ( FIG. 2 ) is utilized to confirm the placement and adhesion of the label elements  32  as they are applied to the moving web  34 . For label elements  32  which are of a metallic character, the placement sensor  56  is preferably a metallic sensor such as the model AT1-AP-4A inductive proximity sensor available from Automationdirect.com which is believed to have a place of business in Cumming, Ga. USA. In the event that a label is not detected by the placement sensor  56  at the proper placement location, an alarm is sounded and an error message is communicated to the operator display terminal  29 . Of course, other appropriate sensors as may be known to those of skill in the art may be used to detect the placement of nonmetallic labels. 
   Due to the fact that the label applicator  30  according to the present invention preferably utilizes two substantially independent systems for placement of labels  32  along the moving web  34 , these dual systems may be used either independently or in conjunction with one another to effect the desired placement of labels. That is, the label discharge mechanisms  44  may be used alternately to place individual label elements  32  upon the moving web  34  or may be operated substantially independently of one another. Moreover, in the event that one or more components of either system becomes dysfunctional, it is contemplated that label application may nonetheless proceed using the components of the other application system until necessary repairs may be undertaken. By way of example, the dual systems may be used to mark the beginning and the end of running defects as may occur along the length of the moving web  34 . 
   As will be appreciated, in many industries and/or environments, the availability of space is limited. In such environments, the label application unit  30  of the present invention may be adjusted to carry out the label placement function when the web  34  is in a non-horizontal position. As best illustrated in  FIG. 4 , the label application unit  30  according to the present invention is adaptable to virtually any position through the positional adjustment of a supporting rail structure  60  relative to the structural frame  31 . Moreover, the label application unit  30  is capable of movement along the length of the rail structure  60  so as to track the edge of the moving web  34  such that label placement relative to the edge is consistent regardless of variations in the path of travel of the moving web  34 . Such tracking is preferably carried out in a manner well known to those of skill in the art through use of two retroreflective photoelectric sensors in opposing relation to a reflective surface over which the web  34  is conveyed. One of the sensors is arranged to be slightly outboard of the edge of the web  34  while the other of the sensors is oriented to be slightly inboard of the edge of the web  34 . In the event that the desired alignment is lost, the label application unit  30  is moved along the length of the rail structure  60  until proper alignment is regained. 
   As shown, the supporting rail structure  60  is preferably carried on a cross support member  62  which is connected to an adjustable flange member  64 . The adjustable flange member  64  is connected to the structural frame  31  by a plurality of threaded holes which accept bolts  68  extending through arcuate openings  70  within the adjustable flange member  64 . Thus, by loosening and/or removing the bolts  68 , the adjustable flange member  64  may be rotated until the supporting rail structure  60  is in the desired position at which point the bolts  68  may be reapplied and tightened so as to place the adjustable flange member  64  into a secure position. Due to the fact that the arcuate openings  70  extend in segmented fashion substantially around the entire perimeter of the adjustable flange member  64 , the supporting rail structure  60  can be oriented at virtually any position around the 360° perimeter of the adjustable flange member. The supporting rail structure  60  may thereafter be attached to any suitable stand  72  or other suitable structures such as in overhead hanging support as may be desired. 
   By way of example only, and not limitation, an orientation for the label applicator  30  to accommodate a moving web  34  moving substantially vertically is illustrated in FIG.  5 . As will be appreciated, such an orientation is achieved by rotating the adjustable flange member  64  and corresponding supporting rail structure  60  approximately 90° from the position illustrated in FIG.  4 . Operation of the label applicator  30  in such a position is in all respects identical to that as previously discussed with respect to the horizontal moving web. 
   In accordance with the above description, it may be seen that the present invention provides a useful and highly versatile device for the attachment of marking labels to webs of material. Moreover, the label application unit  30  according to the present invention is useful with webs traveling at various rates of speed as well as in various physical orientations. While the present invention has been illustrated and described in relation to particular potentially preferred embodiments, it is to be understood that such embodiments are illustrative only. Accordingly it is not the intention that the invention be limited to such illustrated and described embodiments, but rather than the invention will extend to the full spirit and scope of the claims appended hereto.