ENGRAVING MACHINE

Abstract

A laser engraving machine with a three-point suspension system and an inverted X-Y axis support system wherein the X-axis beam is to and mounted below the Y-axis beams and the Y-axis beams are mounted inwardly of the outer ends of the X-axis beam and are structurally integrated with the machine housing. In addition, a counterweight in the form of a second, independently activatable laser is added to the drive belt to reduce or eliminate vibration during rapid reciprocal movement of the tool during an engraving process.

Claims

1. An engraving machine X-axis drive system comprising: a closed loop drive belt with a stepper motor drive; said belt being mounted on and extending between a pair of pulleys to define two parallel spans of the belt that move in opposite directions; an engraving tool in the form of a first laser having a known mass attached to one side span of the belt for movement therewith; and a counterweight comprising a second laser of substantially the same mass as the first laser attached to a second side span of the belt for movement therewith in a direction opposite to that of the first laser.

2. An engraving machine X-axis drive system as defined in claim 1 wherein the pulleys have parallel vertical axes or rotation.

3. An engraving machine X-axis drive system as defined in claim 1 further including means for independently activating the first and second lasers during X-axis scans thereof.

4. An engraving machine X-axis drive system as defined in claim 2 wherein the first and second lasers are mounted so as to produce laser beams extending along a vertical Z-axis.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is diagrammatic view of the prior art X and Y beam support structure;

[0009] FIG. 2 is diagrammatic view of the new X and Y beam laser support structure;

[0010] FIG. 3 is a perspective view of a laser machine including a laser cabinet having X and Y engraving tool translation capability and a pair of lasers 10 and 13 mounted for movement in opposite directions on opposite sides of a grooved stepper motor drive belt; and

[0011] FIG. 4 is a bottom view of the apparatus of FIG. 3 showing the use of two laser in a counterweighted fashion on opposite sides of the X-axis incremental drive belt 42.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENT

[0012] Reviewing, the prior art X and Y beam structure diagrammatically shown in FIG. 1, it should be noted that the X-axis support beam 12 is mounted over the widely spaced Y-axis support beams 12 and 14 to allow the laser tool 10 to realize maximum translation scope in the positive and negative X-axis direction.

[0013] FIG. 2 on the other hand, shows the new arrangement in which the laser tool 10 and the X-axis support structure 18 is mounted to and below the Y-axis support beams 20 and 22 thereby allowing those beam structures to be moved closer together, adding substantial additional rigidity to the housing 24 shown in FIGS. 3 and 4.

[0014] Referring to FIGS. 3 and 4, the laser machine 24 is shown to comprise a box-like metal housing with an interior volume adapted to contain the X-axis support structure 18 for the downwardly-aimed laser engraving tool 10 which is moveable along the X-axis by means of a belt 42 mounted on pulleys 44 and 46 driven by a stepper motor 43 as disclosed in my prior patent documents as described above. Y-axis drive is provided by a second stepper motor 45. The housing sits, in this example, on the top surface of a table 36, which is mounted over an elevator table 38 on which the object 40 is to be engraved rests. The elevator table allows the object 40 to be put in place and then raised up into the focal range of the laser tool 10.

[0015] However, additional adjustment for both laser focus and the accommodation of any non-level condition in the surface of the object 40 to be engraved, is provided by means of the three-point tool support and guidance system incorporating screw shafts 26, 28 and 30 arranged in a triangular pattern and adjustable in this case by hand to allow leveling of the laser tool translation field so that it parallels the surface of the object 10 to be engraved. Again, this is fully described in my prior art patent.

[0016] In accordance with the invention, and the novel subject matter described herein, the Y-axis beams 20 and 22, which extend between and are affixed to the front and rear panels of the housing 24 are mounted closer together without having a negative effect on X-axis translation scope. The Y-axis beams are structurally tied into the front and rear-housing panels adding substantial rigidity to the housing and, as described above, allowing for the use of lighter, less expensive materials of construction.

[0017] The cabinet or housing 24 has a hinged lid 32 with an exhaust port 34 connected to an exhaust system (not shown) to evacuate dust and debris as well as smoke from the area where the laser tool 10 is operating. Similar machinery is used where the engraving tool 10 takes the form of a mechanical device such a diamond tip rotary tool. Maximum structural rigidity is provided by locating the Y axis beams 20 and 22 at the one-third and two-thirds distance points between the side panels 23 and 25 of the housing. By way of example, for a housing or cabinet that provides a 48 inch field, the beam 20 is located at least approximately 16 inches from the side panel 23 while beam 22 is 32 inches from the side panel 23 and 16 inches from beam 20.Variations of this spacing are also advantageous and may be necessary to accommodate various factors such as cabinet design and the mounting locations of the various internal components.

[0018] As indicated above, another aspect of the innovative subject matter described herein is the addition of a counterweight, here in the form of a second laser tool 13 identical to laser tool 10, mounted on the belt 42 directly opposite; i.e., on the other side of the belt 42 so that as the laser engraving tool 10 moves from right to left during the incremental engraving process, the tool 13 moves from left to right and vice versa. The mass of the counterweight is chosen to be at least substantially equal the mass of the tool and, as will be understood, moves in directions opposite to movement of the tool. This gives rise to a conservation of momentum, which damps out the tendency of a single laser engraving tool 10 to vibrate or flex the belt 42 during the rapid reciprocal incremental movement of the tool during a very fine, high resolution engraving process. The result is substantial improvement in the resolution of the images and other figures to be engraved.

[0019] Looking further to FIG. 4, the laser source 50 is shown mounted toward the back of the cabinet and the output is aimed at a mirror 52 which redirects the beam to a second beam-splitter mirror 54 which in turn directs the beam to the laser tool 13. The beam also passes through the mirror 54 to a second mirror 56 which directs the beam to the laser tool 10. It will be understood that two lasers may be used with two sets of mirrors to transmit their respective beams to the tools 10 and 13 so that they may operate essentially independent of one another during an engraving process.

[0020] It is to be further understood that the invention has been described with reference to an embodiment which is deemed to be illustrative in nature and that persons skilled in the art will see and understand that various modifications and additions to the subject matter described herein may be made.