Abstract:
A laser beam containment system includes a number of optics that direct a laser beam produced by a laser beam source along a path to a point of application of the laser beam. One or more hollow tubes are positioned in an arrangement such that the laser beam passes through the hollow tubes. The hollow tubes are also adjustably positioned relative to the laser beam objects to allow for access to the optics for maintenance and adjustment of the optics. Locking mechanisms provide control of the adjustment features of the containment tubes.

Description:
BACKGROUND  
       [0001]     High energy laser radiation is used in various manufacturing operations such as perforation of cigarette paper used in the manufacture of cigarettes. During manufacturing operations using a laser beam, the beam is generally directed along a path to a point of application, where the beam&#39;s energy can be focused and used to perform an operation on a workpiece such as producing a hole through cigarette paper. Various optics are used to direct and control the laser beam such that the desired results are achieved. Such optics can include bending mirrors, shutter assemblies, beam expanders and beam contractors, rotating, multi-faceted mirrors capable of dividing the laser beam into multiple output laser beams and scanning the output laser beams across a desired arc, collimating lenses and focusing lenses.  
         [0002]     A laser beam having sufficient energy to perform a manufacturing operation such as perforation of cigarette paper has the potential to present a hazard to an operator if the operator comes into contact with the laser beam somewhere along its path from the laser beam source to its point of application. For example, maintenance and adjustment of the optics used to direct and control the laser beam could result in an operator coming into contact with the laser beam along its path.  
       SUMMARY  
       [0003]     In an arrangement according to one embodiment, a laser beam containment system protects a user from unauthorized or unintentional exposure to the laser radiation. A laser beam containment system according to one embodiment includes a plurality of optics, including but not limited to flat mirrors, that direct a laser beam produced by a laser beam source along a path to a point of application of the laser beam. One or more hollow tubes are positioned in an arrangement wherein the laser beam passes through the hollow tubes. At least one of the hollow tubes is adjustably positioned relative to at least one of the optics to allow for access to the optic for at least one of maintenance and adjustment of the optic. 
     
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES  
       [0004]      FIG. 1  illustrates an arrangement of hollow laser beam containment tubes according to an embodiment.  
         [0005]      FIG. 2  illustrates a portion of one of the hollow tubes from  FIG. 1  adjustably positioned to allow access to a laser mirror.  
         [0006]      FIG. 3  illustrates a portion of a hollow tube from the arrangement shown in  FIG. 1 , and illustrates the positioning of a laser beam alignment device within the hollow tube.  
         [0007]      FIG. 4  illustrates an arrangement of hollow laser beam containment tubes and laser beam optics defining two paths for laser beams being emitted from a laser beam source. 
     
    
     DETAILED DESCRIPTION  
       [0008]     Referring initially to  FIG. 1 , an arrangement for a laser beam containment system according to an embodiment includes hollow containment tubes  22   a,    22   b  and  22   c,  laser beam bending blocks  32   a  and  32   b  containing mirrors  34   a  and  34   b,  and a pivotally mounted target block assembly  20  that is pivotally mounted to laser beam bending block  32   b.  While tubes having a square cross-section are shown in the drawings, the tubes can have any desired configuration such as round, rectangular, etc.  
         [0009]     As shown in  FIG. 1 , a first end of the hollow tube  22   a  fits over a flange  10  protruding from an output port on a laser generating device, such as a PRC 3000 watt dual beam GE mode laser (shown in  FIG. 4 ), manufactured by PRC Corporation, Landing, N.J. The end of the hollow tube  22   a  that fits over the flange  10  can be retained in position relative to the flange through the use of a slot  22   a ′ in the hollow tube  22   a  and a clasp  12  extending from the flange  10 , which can be mated and held in position relative to each other using a padlock  14 . As shown in  FIG. 1 , the opposite end of the hollow tube  22   a  fits over a flange  33   a  of the laser beam bending block  32   a,  which houses bending mirror  34   a.    
         [0010]     A laser beam emitted from the laser source  100 , shown in  FIG. 4 , travels through the hollow tube  22   a  and is reflected off of the bending mirror  34   a  within the housing or bending block  32   a.  A further hollow tube  22   b  slides over flange  33   a  of the bending block  32   a  on a side of the bending block  32   a  that is orthogonal to the side receiving the incoming laser beam, or at another angle to the side receiving the incoming laser beam depending on the arrangement and particular type of optic mounted within the bending block. As shown in  FIG. 1 , the opposite end of the hollow tube  22   b  from the end that fits over the flange  33   a  of bending block  32   a,  fits over another hollow tube portion formed from a solid bar  25  having a longitudinal laser beam passage  25 ″ bored through the center. The laser beam reflected from bending mirror  34   a  within laser beam bending block  32   a  travels through the hollow tube  22   b  and through the passage  25 ″.  
         [0011]     As best seen in  FIG. 2 , the end of bar  25  opposite from the end  25   a  that fits within hollow tube  22   b,  is pivotally mounted by a hinged mechanism  42 ,  44  to another laser beam bending block  32   b  containing a bending mirror  34   b.  The pivotal mounting of the bar  25  allows the assembly  20  to be pivoted from a position wherein the central longitudinal passage  25 ″ is aligned with an opening  32   b ′ and bending mirror  34   b  within laser beam bending block  32   b,  to a position where the bar  25  is moved away from the opening  32   b ′ to allow for access to the bending mirror  34   b.  As further shown in  FIG. 2 , the opening  32   b ′ in bending block  32   b  is provided with an O-ring dust seal  35  that seals against the end face of the end  25   b  of the bar  25 .  
         [0012]     As shown in  FIG. 2 , the assembly  20  also includes a sleeve  26  that is slidably mounted on the bar  25  and adapted to be moved from the one end  25   b  (shown in  FIG. 3 ) of the bar  25  toward and away from the opposite end  25   a  of the bar  25 . A transverse passageway  25 ′, shown in  FIG. 3 , extends through the end  25   b  of bar  25  and intersects the longitudinal passageway  25 ″ through the bar  25 . The transverse passageway  25 ′ is adapted to receive a target block  52  that is used for alignment of the laser beam passing between bending mirror  34   a  and bending mirror  34   b  and through the hollow tube  22   b  and the longitudinal passageway  25 ″ of bar  25 .  
         [0013]     As shown in  FIG. 3 , an alignment procedure for aligning the laser beam passing between bending mirrors  34   a  and  34   b  can be performed by sliding the sleeve  26  from the end  25   b  of bar  25  toward the end  25   a  of bar  25  in order to uncover the transverse passageway  25 ′. A target block  52  can then be lowered into the transverse passageway  25 ′ during the alignment procedure. A marking device such as a wood tongue depressor  62  is then positioned relative to the target block  52 , and the laser beam turned on for a short time with the result that cross-hairs formed by the target block  52  are burned into the wood marking device  62 . This enables an operator to make adjustments to ensure that the laser beam traveling from bending mirror  34   a  to bending mirror  34   b  is properly positioned relative to the containment tube  22   b  and pivotable assembly  20 .  
         [0014]     During normal operation when neither maintenance nor alignment of the laser beam are being performed, the hollow tube  22   b  and bar  25  can be retained in position by installing a locking sleeve or shield  72  on the outside of bar  25  between an end of the slidable sleeve  26  and the end of the hollow tube  22   b,  as shown in  FIG. 1 . The locking sleeve  72  can be retained in position through the use of a latch assembly  72   a,    72   b,  thus preventing the sliding sleeve  26  from being moved away from the end  25   b  of the bar  25 , and preventing hollow tube  22   b  from being moved off of the flange  33   a  of laser beam bending block  32   a  since the distance between bending block  32   a  and bending block  32   b  is fixed as a result of the overall system constraints, such as shown in  FIG. 4 .  
         [0015]     As shown in  FIG. 4 , an arrangement according to one embodiment of the invention directs two separate laser beams from a laser source  100  to a multiplexer  200  that contains two rotating multi-faceted mirrors (not shown) for dividing the laser beams and scanning them across further downstream optics. As shown in  FIG. 4 , laser beams exiting the laser source  100  travel through the interiors of hollow tubes  22   a,    22   b,    22   c,    22   d,    22   e,    22   f,    22   g,  and  22   h,  and through pivoting target block assemblies  20  that are provided along the paths between each of the bending mirrors  32  to allow for alignment and maintenance of the mirrors.  
         [0016]     In operation of the arrangement shown in  FIG. 4 , laser beam radiation exits the laser generating device  100  and enters a first hollow containment tube  22   a,    22   e  until it reaches a first bending mirror block  32 . As shown in the embodiment of  FIG. 1 , an arrangement for connecting the tubes  22   a,    22   e  includes flange  10  on the laser beam source  100  and flange  33   a  on the first bending block  32   a,  which mate with opposite ends of the first hollow tube  22   a.  Tubes  22   a,    22   e  can be held on the flange  10  by a locking arrangement such as a projection on flange  10  passing through a slot  22   a ′ at one end of the hollow tube  22   a  and a retaining device such as a padlock  14  to retain the hollow tube  22   a  in position between the laser source  100  and the first bending mirror  34   a.    
         [0017]     The laser beam reflected from the first bending mirror  34   a  travels through the interior of hollow tube  22   b  and through the center longitudinal passageway  25 ″ in bar  25  between the reflective surfaces of the mirrors  34   a  and  34   b.  One end of the hollow tube  22   b  is captured on the flange  33   a  of laser beam bending block  32   a,  and the opposite end of the hollow tube  22   b  fits telescopically over an end of the bar  25 . A pushbutton release  27  is provided at the end  25   a  of bar  25  to retain the hollow tube  22   b  in position over the flange  33   a  of laser beam bending block  32   a.  Release of the pushbutton  27  allows the sleeve  22   b  to be slid telescopically over the outside surface of bar  25  and removed from engagement with the laser beam bending block  32   a.  However, as discussed above, a locking sleeve  72  can be positioned between the end of hollow tube  22   b  and outer sleeve  26  on the bar  25  to prevent movement of either the sleeve  26  or the hollow tube  22   b.    
         [0018]     In an initial alignment procedure, bending mirror  34   a  can be aligned with bending mirror  34   b  by first removing the locking sleeve  72  from between hollow tube  22   b  and outer sleeve  26  of the bar  25  in order to allow the sleeve  26  to be slid out of the way to provide access to the transverse passageway  25 ′ through bar  25 . Furthermore, removal of the locking sleeve  72  and release of pushbutton  27  allows the hollow tube  22   b  to be slid off of the flange  33   a  of laser beam bending block  32   a,  and the assembly  20  can then be pivoted about hinge mechanism  42 ,  44  to provide access to bending mirror  34   b  within the laser beam bending block  32   b.    
         [0019]     Although the arrangement according to an embodiment of the invention shown in  FIG. 1  shows containment of the laser beam passing between bending mirrors  34   a  and  34   b  as achieved by a hollow tube  22   b  that fits telescopically over a bar  25 , it will be recognized that other arrangements could include more than one hollow tube and/or bar that are adjustably positioned relative to each other and can be locked in place relative to each other using different mechanisms in order to control access to the path of the laser beam and the laser beam optics for alignment and/or maintenance. Other alternative embodiments could include the hollow containment tube portions fitting within openings in the laser beam bending blocks rather then over flanges that extend from the laser beam bending blocks.  
         [0020]     Although the invention has been described with reference to the foregoing embodiments, it will be recognized that alternative arrangements and embodiments can be provided for controlling access to the laser beam and the laser beam optics without departing from the spirit and scope of the claims that are appended.