Patent Publication Number: US-2023158615-A1

Title: Laser engraver machine carriage with vertical adjustability

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims in part the benefit of U.S. Provisional Application Ser. No. 63/282,401, filed on Nov. 23, 2021, the entire contents of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     A carriage of framework construction is designed to support laser machine cabinet and provide motor powered vertical movement of the cabinet to adjust its elevation relative to a workpiece. 
     BRIEF SUMMARY OF THE DISCLOSURE 
     A height-adjustable carriage for a laser engraving machine cabinet is disclosed in my U.S. Pat. No. 8,309,881 issued in November of 2012. The carriage comprises a frame structure with vertically movable engraver cabinet supports mounted on screw shafts driven by stepper motors located at the tops of the shafts. In accordance with the first aspect of the present invention, manual locks are placed on one of the screws shafts on each side of the carriage. The locks can be operated to prevent the weight of the engraver machine from causing the screw shafts to free run as a result of motor failure in the lowering direction and potentially causing damage to the machine and/or a device being engraved such a grave marker. 
     In accordance with a second aspect of the invention, the motors that rotate the screw shafts are located adjacent to the bottoms of the screw shafts where they are less likely to be inadvertently contacted by an operator. This is particularly important after the motors have run long enough to raise the temperature of the motor housings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The carriage will be described with reference to a series of drawings showing the carriage in various stages of assembly. The drawings are briefly described as follows: 
         FIG.  1    is a perspective view of the overall carriage construction with no laser engraving machine mounted within it and with the laser machine carriage mechanism in a lowered position; 
         FIG.  2    is another perspective view of the carriage of  FIG.  1    with the mechanism for engaging and holding the engraving machine in a raised position; 
         FIG.  3    is another perspective view of the carriage from a different angle; 
         FIG.  4    is another perspective view of the carriage from the same angle as  FIG.  3    but with a panel located to the upper rear portion removed to illustrate the location of electronic components including a power supply and a motor drive; 
         FIG.  5    is a perspective drawing of the completed carriage with a laser machine mounted within in it and placed in a fully lowered position; 
         FIG.  6    is another perspective view of the carriage loaded with a laser machine and with the machine in a fully raised position; 
         FIG.  6 A  is identical to  FIG.  6    but shows a workpiece placed within the confines of the carriage and directly beneath the laser engraving machine; 
         FIG.  7    is an exploded view of the carriage without connecting hardware for the various beam like components thereof; 
         FIG.  8    is another exploded view of the carriage with representative showings of typical connecting hardware for the various beams; 
         FIG.  9    is a drawing of an exemplary shaft lock; and 
         FIG.  10    is a drawing of a carriage with the motors  30  relocated to a position at or near the bottom of the side frames. 
     
    
    
     DETAILED DESCRIPTION THE PREFERRED EMBODIMENT 
     Referring now to the figures,  FIGS.  1 - 4    illustrate in perspective a laser engraving machine carriage  10  of rectangular configuration comprising parallel spaced apart vertically oriented side frames  12  and  14  each of which is constructed using metal box beams of which the vertical beams shown at  16  are joined by horizontal top and bottom beams  18  and  20  respectively. Cross beams  22  also of box like construction join the frames  12  and  14  at the top, leaving the bottom of the carriage open for purposes which will become apparent. The connecting hardware used to join the various box beams of the frames  12  and  14  is illustrated in  FIG.  8    and includes a number of metal brackets which are joined to the beams by machine screws in a well-known fashion. The beams may be made of any suitable material but are preferably made of aluminum or steel for dimensional stability and rigidity. Decorative panels  26  may be used to dress up the interior frames  12  and  14  as desired and may be made of a variety of materials including plastic and aluminum sheeting. 
     Each side frame  12  and  14  has fitted within the side beams thereof pair of vertical, spaced apart screw shafts  28  and  32  of which shaft  28  is connected to be rotated by a stepper motor  30  which is secured to the top beam  18  in each of the two frames. 
     The two threaded shafts on each side of the carriage  10  are coupled for synchronized rotation by means of belts  35  near the lower ends as shown in the Figures. 
     A horizontal support in the form of a rectangular pedestal  34  is connected between each set of screw shafts  28  and  32  by means of internally threaded couplings  36 . Accordingly, activation of the stepper motors  30  rotates the shaft  28  and  32 , the two shafts being coupled for simultaneous rotation by means of the belts  35 . Since the pedestals  34  are carried by the shafts and are connected to the shaft by means of the internally threaded couplings  36 , rotation of the shafts  28  and  32  by the stepper motors  30  causes the pedestals to synchronously raise and lower vertically by reason of the fact that the two stepper motors  30  are controlled by the same motor controller shown exposed in  FIG.  4   . 
     Locks  31  with manually operated levers  51  are attached to a screw shaft  32  on each side of the carriage  10  to selectively lock the shafts against inadvertent rotation from a desired elevation caused by the weight of a engraving machine  40  acting as a load on the pedestal  34  in the event of a motor failure. Such a motor failure could allow the screw shafts to free wheel and drop the engraving machine downwardly. As shown in  FIG.  9   , each lock consists of a slotted collar  50  surrounding a screw shaft extension and a lever  51  acts as a cam to squeeze the collars and lock the associated shafts into position when the lever is moved by hand into the locked position. Each lock  31  is mounted by way of a metal bezel  52  with bolt holes allowing it to be attached to a bracket  54  on the top beam of each of the two frames. When the elevation of the laser machine reaches the desired position, the levers on the locks are rotated from a unlocked position to a locking position thereby preventing inadvertent downward movement in the event of motor failure. When vertical adjustment is needed, the levers are rotated to unlock the screw shafts allowing the stepper motors to rotate the screw shafts as desired. 
     As mentioned above,  FIG.  1    shows the pedestals  34  in a partially elevated position whereas  FIG.  2    shows the pedestals  34  in the fully raised position. Again, the motors  30  are simultaneously activated so that the two pedestals  34  on opposite sides of the carriage are always in the same vertical position with one another. Separate mechanisms  42  can be used to change the angular orientation of the laser cabinet if needed; for example, if the object being engraved has a non-level surface. 
       FIG.  3    shows a panel  33  covering a compartment at the top left-hand corner of the side panel  14  shown to the rear of  FIG.  3    and  FIG.  4    shows the same construction but with the stepper motor driver  8  exposed along with the power supply  9  which is used to drive the stepper motor. 
     Referring now to  FIG.  5   , the carriage  10  is shown with a laser engraving machine  40  of the type described in my U.S. Pat. No. 10,654,127 issued in May of 2020. The laser engraving machine  40  is mounted to and between the pedestals  34  to be supported thereby. The machine  40  may simply rest on the pedestals or may be secured to them by means of hardware  42  which is fitted to the side panels of the laser housing so that the laser housing is raised and lowered along with the vertical motion of the pedestals  34  on the left and right sides of the carriage  10 . The hardware  42  may include thumb wheel screw shafts which allow a degree of angular change in the orientation of the laser machine housing  40  in the event the workpiece to be engraved by the laser which is pointed through the bottom of the laser machine housing is not level. The figures, particularly  FIGS.  5  and  6   , however show the laser machine in a level position such that the X-Y field of laser displacement is horizontal. 
       FIG.  6 A  shows the laser cabinet  40  within the carriage  10  in the fully raised position and a workpiece  46 , in this case a granite headstone, is placed within the space between the side frames  12  and  14  of the carriage and directly below the open bottom lasers such that the downwardly pointed or vertically pointed laser can etch a graphic or letters and numbers providing information in the top surface  48  of the workpiece. Of course, in normal operation the carriage would be activated to lower the pedestals and bring the laser engraving machine  40  down closer to the surface  48  of the headstone  46  and maintain the laser at the correct focal distance from the workpiece during the laser engraving operation. 
     As those skilled in the art will understand the laser engraving operation comprises a programed repeating horizontal scan to etch and remove material from the surface  48  of the workpiece according to a program that is entered in into the laser engraving machine digitally according to a pattern that produces number, letters and/or images. 
     As indicated previously  FIGS.  7  and  8    show the carriage components exploded; i.e. taken apart with the cross beam  22  and  24  not yet joined to the otherwise fully constructed side panels  12  and  14 . On the other hand  FIG.  8    shows the various components of hardware which are preferably made of metal and joined by machine screws to the metal box beams of the side panels to complete the construction of the carriage. The dimensions of the carriage both vertically, horizontally and depth wise can vary according to the size range of the laser engraving machines placed therein. Typically, dimensions might be 24″ in height, 50″ plus in horizontal width and approximately 36″ in depth but the dimensions are not to taken limiting as the carriage dimensions according to the specific use. 
     Referring to  FIG.  10    the embodiment there shown includes a frame structure as essentially shown in  FIGS.  1 - 8   . However, the motors  30  are relocated to a position at or near the bottom of the shafts driven thereby through gear sets as shown. This removes the motor from the upper locations there by reducing the number of control elements at and around the top of the frame and further reducing the likelihood of inadvertent contact between an operator and the stepper motors as explained above.