LASER ENGRAVER MACHINE CARRIAGE WITH VERTICAL ADJUSTABILITY

A frame like structure supporting a laser engraving machine between left and right vertically adjustable pedestal. Each pedestal is mounted to a set of vertically oriented screw shafts wherein at least one shaft on each side frame is driven by a stepper motor connected to the screw shaft adjacent the bottom end thereof. Manually operated locks are provided at the tops of the screw shaft to prevent inadvertent rotation caused by the weight of the engraving machine in the event of a motor failure. The pairs of screw shafts on each side of the frame are coupled by belts to permit one motor to rotate both shafts and one lock to lock both shafts.

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.

DETAILED DESCRIPTION THE PREFERRED EMBODIMENT

Referring now to the figures,FIGS.1-4illustrate in perspective a laser engraving machine carriage10of rectangular configuration comprising parallel spaced apart vertically oriented side frames12and14each of which is constructed using metal box beams of which the vertical beams shown at16are joined by horizontal top and bottom beams18and20respectively. Cross beams22also of box like construction join the frames12and14at 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 frames12and14is illustrated inFIG.8and 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 panels26may be used to dress up the interior frames12and14as desired and may be made of a variety of materials including plastic and aluminum sheeting.

Each side frame12and14has fitted within the side beams thereof pair of vertical, spaced apart screw shafts28and32of which shaft28is connected to be rotated by a stepper motor30which is secured to the top beam18in each of the two frames.

The two threaded shafts on each side of the carriage10are coupled for synchronized rotation by means of belts35near the lower ends as shown in the Figures.

A horizontal support in the form of a rectangular pedestal34is connected between each set of screw shafts28and32by means of internally threaded couplings36. Accordingly, activation of the stepper motors30rotates the shaft28and32, the two shafts being coupled for simultaneous rotation by means of the belts35. Since the pedestals34are carried by the shafts and are connected to the shaft by means of the internally threaded couplings36, rotation of the shafts28and32by the stepper motors30causes the pedestals to synchronously raise and lower vertically by reason of the fact that the two stepper motors30are controlled by the same motor controller shown exposed inFIG.4.

Locks31with manually operated levers51are attached to a screw shaft32on each side of the carriage10to selectively lock the shafts against inadvertent rotation from a desired elevation caused by the weight of a engraving machine40acting as a load on the pedestal34in 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 inFIG.9, each lock consists of a slotted collar50surrounding a screw shaft extension and a lever51acts 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 lock31is mounted by way of a metal bezel52with bolt holes allowing it to be attached to a bracket54on 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.1shows the pedestals34in a partially elevated position whereasFIG.2shows the pedestals34in the fully raised position. Again, the motors30are simultaneously activated so that the two pedestals34on opposite sides of the carriage are always in the same vertical position with one another. Separate mechanisms42can 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.3shows a panel33covering a compartment at the top left-hand corner of the side panel14shown to the rear ofFIG.3andFIG.4shows the same construction but with the stepper motor driver8exposed along with the power supply9which is used to drive the stepper motor.

Referring now toFIG.5, the carriage10is shown with a laser engraving machine40of the type described in my U.S. Pat. No. 10,654,127 issued in May of 2020. The laser engraving machine40is mounted to and between the pedestals34to be supported thereby. The machine40may simply rest on the pedestals or may be secured to them by means of hardware42which 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 pedestals34on the left and right sides of the carriage10. The hardware42may include thumb wheel screw shafts which allow a degree of angular change in the orientation of the laser machine housing40in 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, particularlyFIGS.5and6, however show the laser machine in a level position such that the X-Y field of laser displacement is horizontal.

FIG.6Ashows the laser cabinet40within the carriage10in the fully raised position and a workpiece46, in this case a granite headstone, is placed within the space between the side frames12and14of 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 surface48of the workpiece. Of course, in normal operation the carriage would be activated to lower the pedestals and bring the laser engraving machine40down closer to the surface48of the headstone46and 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 surface48of 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 previouslyFIGS.7and8show the carriage components exploded; i.e. taken apart with the cross beam22and24not yet joined to the otherwise fully constructed side panels12and14. On the other handFIG.8shows 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 toFIG.10the embodiment there shown includes a frame structure as essentially shown inFIGS.1-8. However, the motors30are 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.