US2703455A

US2703455A - Autoradial engraving device

Info

Publication number: US2703455A
Application number: US154830A
Authority: US
Inventors: Edwin T Green
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-04-08
Filing date: 1950-04-08
Publication date: 1955-03-08
Anticipated expiration: 1972-03-08

Description

March 8, 1955 E. T. GREEN 2,703,455

AUTORADIAL ENGRAVING DEVICE Filed April 8, 1950 6 Sheets-Sheet 1 A iii s.

March 8, 1955 E. T. GREEN 2,703,455

AUTORADIAL ENGRAVING DEVICE Filed April 8, 1950 6 Sheets-Sheet 3 69 m1 1 5% I. Y

W j M 36 Inventor; I .flwim Z 'raerz, y @fl W 7'- v At j/s.

March 8, 1955 E. T. GREEN 2,703,455

AUTORADIAL ENGRAVING DEVICE Filed April 8, 1950 6 Sheets-Sheet 4 Edwin 1 Green,

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March 8, 1955 E. T. GREEN 2,703,455

AUTORADIAL ENGRAVING DEVICE TOGREENL/ United States Patent AUTORADIAL ENGRAVING DEVICE Edwin T. Green, Cambridge, Mass.

Application April 8, 1950, Serial No. 154,830

9 Claims. (Cl. 33-23) This invention relates to an auto-radial engraving device, designed to be attached to a standard pantographic engraving machine, or a milling machine, or the like, for the purpose of engraving a radial, circular, or arcuate design or legend on a work piece from a straight-line master copy.

Previously, so far as I am aware, engraving in radial, circular or arcuate designs has been done by hand, by using a single letter die for instance, and striking it with a hammer, or from a rotating table mounted on a pantograph engraving machine, and in which successive letters are placed in, or moved to the center position on the master copy. Such engraving, as illustrated by the designs and lettering placed on notarial and corporate seals, for instance, requires great skill and experience on the part of the engraver to get the proper spacing, radius, arc, and size of design or lettering. The spacing of the letters or design has to be carefully estimated in advance, with hand lay-out work, and experiment on a trial and error basis, to center the design in the available space and to space the letters evenly. The work very frequently is spoiled and has to be discarded, and it can be done at all only with highly skilled labor which greatly increases the cost of such engraving.

I have been able to overcome the many problems involved therein, and have succeeded in providing a device for radial or circular engraving from a. straight-line master copy and which can be adapted for use in any standard pantograph engraving machine. The operator transfers the letters or design from the straight-line master copy to the work piece, and engraves the desired design thereon in a circular or arcuate form, in any desired size, radius, are, or in any desired spacing between the letters, or other elements of the design. The size and spacing of the lettering or design is determined by the pantograph adjustment, as in standard straight line engraving, and by the travel adjustment of the work carriage on my device. The radius, arc, or circumference of the design is obtained from the center position of a rotating or rolling work table, conical on its underside, which is adjustable with respect to the tangent point p of a fixed transverse friction bar which engages the table on its underside and determines the radius of rotation of the table as it rolls transversely across the bed of the engraving machine, rotating the work piece with it, and presenting successive areas for engraving. The proper size, radius, arc, and spacing of the design is readily determined in advance of cutting by adjusting the usual settings of the pantograph machine according to the desired proportion of the work to be done in relation to the master copy and in proper relation to the radius of the work which is to be inscribed, as by a tentative setting of the machine, and a trial run without actual cutting, and then making such adjustments in the setting of the machine as may be necessary, until the proper setting for the desired purpose is achieved. The proper adjustment of the machine then automatically provides proper spacing of the letters within the determined work radius. Thus, by means of my device, radial or circular engraving is made possible for the first time with a standard engraving machine,

with the same flexibility and adjustability as to size, radius, arc, and spacing of design as was previously possible only in straight line engraving. The spacing of letters and the radius in which they are placed are thus made infinitely and continuously variable within the size limitations of the machine itself and the work 2,703,455 Patented Mar. 8, 1955 piece. The cost of radial, circular, or arcuate engraving is reduced at least one-half and possibly two-thirds, by the use of my device, because highly skilled labor 1s no longer necessary.

Before explaining in detail the present invention it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also 1t1s to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation, and it is not intended to limit the invention claimed herein beyond the requirements of the prior art.

Other advantages and features of my device appear III the accompanying specification and drawings, in which: I

Fig. 1 is a plan view of my device mounted on an engraving machine;

Fig. 2 is a side elevation of my device, seen from the right of Fig. 1;

Fig. 3 is a plan view of my device, with parts removed;

4 is a front elevation of my device;

F F1%. 5 is a transverse vertical section on line 55 of Fig. 6 is a longitudinal vertical section on line 6-6 of Fig. 4;

Fig. 7 is a plan view of my device, showing the position of parts at the beginning and end of an indicated engraving;

Fig. 8 is a diagrammatic view showing manner in which a design is transferred to a circular work piece;-

Fig. 9 is an enlarged diagrammatic view showing the position of parts at the beginning and end of an indicated engraving;

Fig. 10 is a diagram showing the operation of the sliding cam and bar of the brake release mechanism;

Fig. 11 is an enlarged diagrammatic view of the brake release mechanism; and

Fig. 12 is an illustration of the type of work which can be done by my device.

In the drawings (Figs. 1 and 2) 10 represents the bed of a standard pantograph engraving machine on which my radial engraving device is mounted. The engraving machine shown in the drawings is in fact an improved type of engraving machine shown and described in applicants application for Letters Patent Serial No. 739,159, filed April 3, 1947, now Patent No. 2,627,658 issued February 10, 1953, but for present purposes may be regarded as illustrative of a pantograph engraving machine on which, and in combination with which, my present auto-radial engraving device may be used. The principal parts of such an engraving machine as shown herein includes the bed 10 having a flat supporting surface 11, a vertical post 12 preferably arranged at the rear of the machine and having pivotally mounted thereon for vertical adjustment a pantograph structure generally indicated at 14. The pantograph structure 14 includes horizontal arms 16 pivotally engaging the vertical post 12, a four-bar linkage generally indicated at 18 and carrying at its front end the stylus 20 which moves on the master copy 22, the movement of which is transmitted proportionately through the linkages 18 to the cutting tool 24 mounted on vertical spindle 26 and driven by electric motor 28 and belt 29, to make an engraving corresponding to the master copy 22 on the work piece. As a pantograph engraving machine as such is well known in the art, its structure and operation need not be described in further detail. The standard pantograph engraving machine, of course, engraves a straight line legend on the work piece, corresponding to that of the master copy 22, but indefinitely varying in size proportionately, as may be desired. To permit radial or circular engraving on the work piece, but also definitely varying in size proportionately, my device is adapted to be mounted on the standard pantograph engraving machine.

My radial engraving device, as mounted on and used in combination with pantograph engraving machine includes a base plate 35, which is attached by appropriate means such as pins 36 to the supporting surface 11 of base of the pantograph engraving machine in suitable holes provided in base 10. Base plate 35 is preferably cast in a single piece and includes a dovetailed groove 37 extending transversely across the base plate 35 in which the dovetail slide 38 is slidably mounted for transverse horizontal movement. At the front of the base plate 35 and raised above the plane thereof is the copy carrier 40 having spaced parallel transverse grooves 41 provided in the upper surface thereof which receive clamping strips 42 detachably mounted therein as by screws 43 in suitably threaded holes provided in said clamping strips 42 and carrier 40. It will be understood that the straight line master copy 22, a flat metal plate having the letters or characters desired to be transferred to the work in a radial or circular pattern thereon, is fixedly mounted on the copy carrier 40 by means of the clamping strips 42 and screws 43. A transverse slotted opening 45 (Figs. 4 and 6) is provided beneath the copy carrier 40 and between the copy carrier 40 and the base plate 35.

Behind the copy carrier 40 and in the top of base plate 35 is an inverted T-shaped slot or groove 48 (Figs. 1 and 6), extending transversely across the base plate 35, which receives the inverted T-shaped sliding bar 50 for transverse sliding movement therein. Sliding bar 50 has a transverse length approximately one-half that of groove 48 of base plate 35. A rectangular block 52 is fixedly arranged on the top side of sliding bar 50 adjacent the right hand end of sliding bar 50 (Figs. 1 and 7), as by screws 53. A sheet metal bracket 54 is in turn mounted on the top front side of block 52 and carries the gauge 55 over-hanging the master copy 22, and having a vertical center line 56 marked thereon which indicates the relative position of the work piece 92 clamped on the turning table 82 (described below) with respect to a letter or other character on the master copy 22. The rear clamping plate 42 (Fig. 1) which holds the master copy 22 is provided with a series of uniform spaces numbered consecutively 1 to 11 in opposite directions transversely from a center position marked 0. A central aperture 57 is placed on the top side of gauge 55 behind center line 56 to permit reading of the numbered spaces marked off beneath on rear copy clamp 42. Block 52 further carries a central vertical aperture 58, and a central horizontal bore 59 extending longitudinally of block 52 from front to the rear, to receive the rotatable shaft 60 therein. Shaft 60 is provided on its front end with operating handle 61 which serves as a manual means for moving the parts generally termed the work carriage 30 from left to right of the machine (Figs. 1, 7 and 9) as the engraving operation progresses. For this purpose and as a part of said operating means a fixed transverse rack 62 having teeth 63 is provided in the top surface of plate 35 in a suitable slot therein behind inverted T-slot 48. A pinion 64 with gear teeth on its peripheral surface is mounted on operating shaft 60 Within cylindrical aperture 58 in bracket 52. Pinion 64 has a portion (Figs. 1, 7, 8 and 11) extending forwardly from its hub 64a through which shaft 60 extends, and which carries a slot 64b. Shaft 60 in turn carries a small pin 64c extending outwardly therefrom and through slot 64b. Slot 64b is about twice as wide as pin 64c, and thus lost motion is provided and shaft 60 can be rotated slightly before pin 64c engages one side of slot 64b, and thus turns pinion 64. Pinion 64, of course, cooperates with rack 62, as operating handle 61 and shaft 60 are turned manually in a clockwise direction, to move block 52 and the work carriage mechanism 30 from left to right, transversely across base plate 35, as shown in Figs. 1, 7 and 9. This lost motion in pinion 64 permits the brake 105 to be released without advancing the work carriage 30 or turning work table 82, as will be seen below.

Sliding bar 50 in turn has a ratio bar 66 (Figs. 1, 3 and 7) pivotally mounted on the upper surface of its left hand end and turning on pivot screw 65, and in its rearward portion bar 66 has a central longitudinal slot 67 sliding on pivot screw 68 fixedly mounted on a rearwardly extending arm 69 of a bracket 70, in turn fixedly mounted on the rear left hand upper surface of base plate 35, as by suitable screws 71. Pivot screw 68 thus serves as a fixed pivot for ratio bar 66 as it is moved by sliding bar 50 transversely across the engraving machine and base plate 35. Additional holes are provided in arm 69 whereby the position of pivot screw 68 can be changed,

to adjust the ratio of movement of work carriage 30 and rotation of work table 82, as desired.

A second screw 72 is also mounted in slot 67 of ratio bar 66 adjacent the front end of said slot and between pivot screws 68 and 65. Screw 72 in turn is fixed to the left hand end of laterally extending arm 74, which in turn is fixed as by screws 75 to the base slide 38 which slides in the transverse dovetail groove 37 in base plate 35. Base slide 38, which slides transversely, in turn carries a fixed longitudinally extending dovetail slide 76 mounted thereon, being fixed thereto by screws 78 (Figs. 3 and 5), and having downwardly and inwardly inclined sides (Fig. 5). A sliding block 77, composed of two separate parts 77a and 77b (Fig. 5) divided longitudinally, carries a dovetailed groove on its underside, and is slidably mounted on slide 76 for movement thereon frontwardly and rearwardly (Figs. 3 and 6). Parts 11 and b of block 77 are held together by turn screw 79 with handle 80 (Fig. 5), which provides clamping means for causing block 77 to tightly grip slide 76, and to adjustably position block 77 on slide 76. Block 77 in turn carries work table 82 rotatably mounted on vertical spindle 83 secured in block 77 by central screw 84. A bush 85 secured to the under side of work table 82 at its vertical axis carries ball bearings 86 to permit rotation or turning movement of work table 82 on spindle 83 of block 77. A fixture 88 in turn is dctachably and concentrically mounted on the top side of work table 82 as by screw 89, which screws into the central vertical aperture 90 provided in fixture 88. Fixture 88 serves as a support for the work piece 92, which is preferably provided with a central downwardly extending axle or hub 93 on its under side which fits into the aperture 90 in fixture 88. A cam type of clamp 94 with handle 95 is pivotally mounted in a suitable horizontal slot 96 formed in the side of fixture 88 for tightly clamping work piece 92 in the fixture 88 by tightly engaging axle 93 of the work piece 92. An engaging strip 97 is preferably provided at the end of clamp 94 to prevent the hub 93 of the work piece 92 from being gouged while held tightly gripped. It will be understood that work piece 92, and fixture 88 will vary in construction according to the type of work being engraved, and that fixture 88 may be dispensed with entirely when engraving flat work of the type shown at 92a in Fig. 12. As shown more particularly in Figs. 2, 5 and 6, the under side of work table 82 slopes upwardly from its central axis outwardly toward its edges, as in an inverted cone, for reasons described below.

It will thus be understood from the foregoing construction that in operation, as operating handle 61 is turned in a clockwise direction, pinion 64 on operating shaft 60, engaging rack 62 moves the entire work carriage 30 transversely to the right (as shown in Figs. 1 and 7). The work carriage 30 can be regarded as including the slide 50 attached to the under side of block 52, ratio bar 66, arm 74 and base slide 38 and the parts mounted thereon, including slide 76, sliding block 77, work table 82, spindle 83, fixture 88 and work piece 92. If the work table 82, with fixture 88 and work piece 92 is merely moved transversely to the right, without rotation, the straight line legend of master copy 22 would merely be transmitted in straight line relation to work piece 92. But to translate the straight line legend of the copy 22 into arcuate or circular form on the work piec 92, a turning or rolling movement, counter-clockwise in direction is at the same time given to work table 82 by means which will now be described.

As previously stated, the under surface of work table 82 is slightly conical in shape, and slopes upwardly and outwardly from center to the sides of the table, as shown more particularly in Figs. 2, 5 and 6. A friction bar 98 is pivotally mounted on the rear end of base plate 35 beneath the extending sides of work table 82 and extends transversely across the base plate 35. Friction bar 98 has rearwardly extending

arms

99 and 100, journalled on horizontal pins 101 supported on vertical studs 102, in turn fixedly mounted on the base plate 35, whereby bar 98 is pivotally mounted for vertical movement. Ann is much longer in length than its companion arm 99. and extends rearwardly beyond its point of suspension, and thus constitutes a handle for removing friction bar 98 from engaging relation against the under surface of work table 82 and for returning it to such relation. Friction bar 98 is normally held tensioned upwardly by a series of coil springs 103 bearing against base plate 35. The top surface of friction bar 98 is preferably rounded, sharpened on inclined upwardly to present a sharp bearing surface as well as a smooth rolling point of contact against the under side of work table 82. When friction bar 98 is caused to engage the under surface of work table 82, it provides a tangential holding point for work table 82, indicated at p (Figs. 6, 8 and 9), and as the work carriage 30 is moved transversely to the right in the progress of the engraving operation, work table 82 rolls or turns in a counter-clockwise direction along line 1 (Figs. 8 and 9). The radius of the are or circle on which table 82 turns and hence the radius :r of the are or circle f in which the engraved legend is to be placed on the work piece 92, is determined by the longitudinal position of work table 82 on longitudinal slide 76 with relation to the engaging point p of friction bar 98, and this is fixed by screw 79. As previously pointed out, work table 82 is swivelled for rotation on spindle 83 mounted on sliding block 77, in turn mounted for sliding movement longitudinally of the machine, or frontwardly and rearwardly on slide 76. When the desired radius or are of the circle has been achieved by adjusting the position of work table 82 on slide 76 threaded screw 79 is tightened by manually turning handle 80 on the end thereof, causing the two parts 77a and b of the carriage 77 to tightly grip the slide 76 and thus hold work table 82 firmly in position with respect to the slide 76. Then releasing handle 100 of friction bar 98 allows springs 103 to exert upward pressure and causes the top surface of friction bar 98 to tightly engage the under surface of work table 82 and thus constitute a turning point p on which work table 82 will roll in a counter-clockwise direction as work carriage 30 is moved transversely from left to right on the machine. It will be seen that pinion 64 engages rack 62 when handle 61 of the operating shaft 60 is manually turned in a clockwise direction. To enlarge the arc of the circle on which the engraved legend is to be placed on the work piece 92, clamping screw 79 is released to permit block 77 with work table 82 thereon to be moved forwardly of the machine, on slide 76. This increases the length of radius from the center of rotation of work table 82 to the point of engagement p of work table 82 with friction bar 98, and hence increases the radius of the are on which the engraved legend is placed.

During the engraving operation it is essential, of course, that work table 82 and hence work piece 92 be held rigidly and firmly in position and prevented from rotating or rolling further until desired. For this purpose a brake mechanism is provided, with means for releasing the brake, shown generally in Figs. 1, 3, 5 and 7 and more particularly in enlarged detail in Fig. 11. The brake mechanism includes brake 105 pivotally and longitudinally mounted on base plate 35 to bear against the peripheral edge or side of work table 82. Brake 105 is a vertically and longitudinally extending plate having an inserted bearing surface 106 preferably of tough resilient plastic. Brake 105 is mounted on horizontally and longitudinaly extending pivots 107 in turn mounted in stud 108 in forward edge of arm 74. Brake 105 is normally pressed inwardly or from right to left to bear against the edge of work table 82 by means of leaf springs 110 vertically mounted on the side of base slide 38. Brake 105 thus normally bears against work table 82 and prevents it from rolling or rotating. Means, however, is provided for releasing the brake and permitting the work table 82 to roll or rotate freely about point or line 1 as the work carriage 30 is advanced transversely across the machine during the engraving operation. This brake releasing means (Figs. 3 and 11) includes a horizontal and latterally extending arm 112 extending inwardly from brake 105 under work table 82. A pivoted bar 114 extends transversely across the base plate 35 and carries two rearwardly extending arms 115a and 115b, in turn pivoted about horizontal transverse pivots 116 journalled in blocks 117 mounted on base slide 38. The rear end of arm 115:; extends rearwardly beyond its pivot 116, and under lateral arm 112 of brake 105, and leaf spring 110 normally presses arm 112 downwardly against the rear end of pivoted arm 115a, which turning on pivot 116, thus normally holds transverse bar 114 upwardly in a raised position from base plate 35. Adjustment of the bearing of arm 112 against pivoted arm 115a is provided by means of an ad usting screw 118. Brake release bar 114 is thus normally 6 pressed upwardly, as shown in the full line position of Fig. 11, by spring 110 bearing against brake 105. To release the brake 105, to permit work table 82 to rotate or roll as the engraving operation progresses, a cam 120 (Figs. 10 and 11) preferably of a smooth material, such as plastic, is mounted on an enlarged hub 119 provided on the inner end of operating shaft 60, which is caused to bear downwardly against release bar 114 as operating handle 61 is rotated. As shown in more detail in Fig. 10, cam 120 has a flat lower edge 121 with sharp lower corners 121a and b and in its neutral position with surface 121 parallel to bar 114 cam 120 does not engage bar 114. Thus to release the brake operating handle 61 is turned slightly in a clockwise or counterclockwise direction to cause corner 121a or b of cam 120 to press downwardly against release bar 114, which in turn elevates the rear end of arm 115a to press upwardly against arm 112 of the brake 105, and thus cause the brake to move out of engaging relation with the edge of work table 102. As previously pointed out, a lost motion is provided whereby shaft 60 can be rotated a short distance sufficient to release brake 105, without turning pinion 64 on rack 62 and thus advance the work carriage 30 transversely. This is the distance pin 640 on shaft 60 travels, as shaft 60 is rotated before it engages the sides of slot 64b on pinion 64. Work table 102 can thus be freely rotated about its central pivot or spindle 83, as desired. Further turning of shaft 60, however, causes stud 64c to engage the sides of slot 64b and thus turn pinion 64 on rack 62, to advance work carriage 30 transversely and brake 105 still being held released, work table 102 is thus free to roll, or turn against the turning point 7, provided by friction bar 98, as work carriage 30 advances transversely and the engraving operation progresses, without the opposition of brake 105. When work table 82 has been rolled or rotated to its new position for engraving a new letter or character, brake 105 again engages and presses firmly against the side or edge of work table 82, through the pressure of spring 110. Spring is thus permitted to operate to bring release bar 114 upwardly into non-operating condition, where pin 640 on shaft 60 is maintained even- 2; spaced between the sides of slot 64b on hub of pinion In Fig. 9 there is an enlarged diagrammatic view showing how my device operates. As shown in Fig. 9 the machine is set up to transfer a straight line legend into an arcuate or circular legend on a circular work piece 92 such as a corporate or notarial seal. For clarity the letters on both the master copy 22 and work piece 92 are not reversed as they normally would be for a reverse seal. The proportionate size or ratio between the letters on the master copy 22 and on the work piece 92 is first determined as in any engraving machine through adjustment of the pantograph arms 18, and this relationship is indicated by the distance h and h of Fig. 9. At the same time the radius of the arc of the engraved legend to be placed on the work piece 92 is determined by adjustment of the block 77 on longitudinal slide 76 which is fixed by turning the screw handle 80. The friction bar 98 is then brought up against the under side of work table 82 by depressing the handle 100 which determines the position of the friction line 1 on work table 82. The length of the arc in which the engraved legend is to be placed on the work piece 92 is originally determined by the length of master copy 22, but if variation is required, it is done by adjustment of pivot screw 68 on arm 69. As shown in Figs. 8 and 9, it will be noted that in setting up the work the cutter 24 is placed ap proximately over point p, which serves as a gauging point, in being central to the height h of the legend or letters to be engraved on the work piece, as well as being the contact point of friction bar 98 with work table 82, and in the engraving operation the point p generates the line f on the underside of work table 82. With the master copy 22 positioned on copy carrier 40, the gauge 55 is carried over the first letter E with the center lines corresponding by turning handle 61 and the shaft 60 and the stylus 20 is placed in the upper right hand corner of the first letter B. The stylus 20 traverses the letter B in the usual fashion causing the cutting tool 24 to cut the letter B in the work piece 92 as shown in the left hand position of Fig. 9. On the completion of the letter E, the stylus 20 is positioned at the lower right hand corner of the letter B, and the cutting tool 24 is similarly positioned at the lower right hand corner of the letter B on the Work piece 92. The first letter being completed, handle 61 is rotated in a clockwise direction to advance the work carriage 30 transversely and to bring the center line 56 of gauge 55 across the center of the next character in master copy 22 which is a period. It will be noted that as the work carrier 30 is advanced transversely, the work table 82 is rolled or rotated in a counterclockwise direction turning on its friction point p where grziction bar 98 engages the under surface of work table The table 82 is rotated through the rolling line of frictional contact on the rounded top surface of bar 98 through the rolling tangential contact point p to the conical bottom surface of table 82. As successive settings or spacings on the work piece are required, the frictional contact through point also generates on the bottom surface of table 82 a corresponding arcuate rolling line f whose radius r has been determined by the setting desired. As movement of transverse slide 38 and parts mounted thereon proceeds, it may readily be seen then that through the rotation of table 82 a series of successive points on line 1 are readily and accurately transferred to their corresponding points on arcuate line 7.

This operation is repeated for each successive letter or charatcer in turn until the notation E. T. GREEN. is completed. In Fig. 9 the line of travel of the center line 56 of the gauge 55 is indicated by the line t. At the same time the transverse line of travel of the work table 82 and hence work piece 92 is indicated by the line t. The rolling line of frictional contact of friction bar 98 on the under surface of work table 82 as the latter rolls about friction point p is indicated by the line 1" and the radius of the arc between the center point of work table 82 and work piece 92 and friction point p is indicated by the line r.

It will be noted from the foregoing description that the friction point p at which the friction bar 98 bears against the under surface of work table 82, and the radius from the center of work table 82 to friction point p is varied by adiusting the block 77 on longitudinal slide 76. This method of adjusting a movable center to the fixed frictional contact line f of bar 98 allows for any intermediate radial settings 1' desired, within the limits of movement of block 77, all by the use of only one work table.

In Fig. 8 there is a diagrammatic view showing the manner in which the design is transferred to the circular work piece 92, whereby each letter is transferred and reproduced exactly as it appears on the master copy 22, and without distortion (except, of course, for the proportionate difference in size as desired). For instance, the individual letters are reproduced and transferred from a straight line into an arcuate line. The shape of the letters themselves are unchanged. This result is achieved because each letter is transferred precisely as though it was being reproduced on a straight line copy. as Fig. 8 shows with the letters shown in straight line arrangement as each is reproduced, and transferred into an arcuate arrangement as the work table is rolled on the friction line f. As previously explained, the straight line engraving on a work piece can be done on this device by not rolling or rotating he work table 82 about a friction point p, and by not causing the friction bar 98 to engage the under surface of work table 82. In that case. of course, a straight work piece such as 92a of Fig. 12 is mounted on work table 82 in place of turret 88 and work piece 92. It should be noted that the master copy 22 can be made up of interchangeable separate letters or designs, as shown in Figs. 1, 7 and 9, or of one piece or one plate, as shown in Fig. 12.

As illustrative of the types of work that can be done with my radial engraving device on a standard engraving machine, Figs. 1, 2, 4, 5, 6, 7 and 8 show a fiat circular work piece 92 such as the embossing surface of a notarial or corporate seal. It will be understood that the diameter of the circular work piece thus to be engraved can be varied greatly, and threaded holes 82a on work piece 82 are provided radially around its upper surface to receive screws 125 (Fig. 12) and clamps 126 and to hold work pieces of varying shapes and sizes. In Fig. 12

.a rectangular work piece 92a on which are both arcuate and straight line engraved characters is shown. Work 8 piece 92a in this instance is a pressure indicating dial on which markings and figures representing pressure in pounds per square inch are arranged in arcuate form at the lower side of the work piece 92a. At the right in Fig. 12 an enlarged portion of the straight line master copy 22 is shown from which the dial markings and figures are transmitted in arcuate arrangement to the work piece 92a. At the same time, straight line engraving can be done on the same work piece as indicated by the word PRESSURE at the top of the work piece 92a. As previously stated, for such straight line engraving it is only necessary to release the friction bar 98 from engagement with the under surface of work table 82, and work table 82 will then be held stationary by brake 105 and will not rotate to a new position as the work carriage 30 is advanced transversely during the engraving operation. A further advantage of my device lies in the proportional adjustment it can make on circular indicating dials having markings indicating pounds of pressure, for instance. Frequently the pressure responsive instruments vary greatly in their characteristics and are not uniform. Thus 100 lbs. of pressure, for instance, as shown by tests will not bring the indicating pointer to the same place on the indicating dial. Hitherto it has been necessary to provide a different dial for such instruments with different proportional markings, or even to discard or readjust the pressure indicating instrument itself. With my radial engraving device, however, if the outside range between zero pounds and 100 pounds pressure differs. for instance, between different instruments, it will only be necessary to adjust my engraving device proportionately to the different length between the two indicating marks of zero and 100 pounds pressure and the points in between will then be varied proportionately on the indicating dial. Thus a great saving can be made in preparing indicating dials to be used with particular instruments, which are adjusted to the particular instrument, merely by making the necessary adjustments on my radial engraving device. This, in turn, translates them to the indicating dial and arranges them thereon in proper spacing and in proper arcuate form and length of arc.

It will thus be seen that I have provided a Radial Engraving device of great versatility for use on a standard pantograph engraving machine, and which greatly reduces the cost of making arcuate or circular engravings.

I claim:

1. A device for use with a pantograph engraving machine for translating a straight line legend into an arcuate or circular engraving on a work piece, which comprises a base plate adapted to be mounted on the bed of an engraving machine, a work carriage arranged for transverse slidable movement on said base plate including a transverse slide, a longitudinal slide adjustably mounted on said transverse slide, and a work table rotatably mounted on said longitudinal slide and carrying the work iece thereon, a straight line master copy fixed on said base plate, manual means for moving said Work carriage transversely on said base plate, and means for engaging said work table and providing a holding point for rotating said work table and work piece thereon as said work carriage is moved transversely across said base plate.

2. In combination with an engraving machine having pantograph arms carrying a copy stylus and a cutting tool, a device for translating a straight line legend into an arcuate or circular engraving on a work piece, which comprises a base plate adapted to be mounted on the bed of said engraving machine, a straight line master copy of fixed length, a transverse slide arranged for transverse slidable movement on said base plate, a second slide adjustably mounted for longitudinal movement on said transverse slide, a work table rotatably mounted on said second slide and carrying the work piece thereon, manual means for moving said transverse slide transversely on said base plate and a friction bar for engaging said work table and providing a friction line along which said work table may be rotated as said transverse slide is moved transversely across said base plate.

3. In combination with an engraving machine having pantograph arms carrying a copy stylus and a cutting tool, a device for translating a straight line legend into an arcuate or circular engraving on a work piece, which comprises a base plate adapted to be mounted on the bed of said engraving machine, a straight line master copy of fixed length, a transverse slide arranged for transverse slidable movement on said base plate, a second slide adjustably mounted for longitudinal movement on said transverse slide, a work table rotatably mounted on said second slide and carrying the work piece thereon, manual means for moving said transverse slide transversely on said base plate and a friction bar for engaging said work table and providing a friction line along which said work table may be rotated as said transverse slide is moved transversely across said base plate, a brake for preventing rotation of said work table, and means for releasing said brake while said transverse slide is moved transversely across said base plate.

4. In combination with an engraving machine having pantograph arms carrying a copy stylus and a cutting tool, a device for translating a straight line legend into an arcuate or circular engraving on a work piece, which comprises a base plate adapted to be mounted on the bed of said engraving machine, a straight line master copy of fixed length, a slide arranged for transverse slidable movement on said base plate, a second slide adjustably mounted for longtiudinal movement on said first slide, a work table rotatably mounted on said second slide and carrying the work piece thereon, manual means for moving said first slide transversely on said base plate, a ratio bar for adjustably varying the transverse movement of said first slide with respect to said master copy, and a friction bar for engaging said work table and providing a friction line along which said work table may be rotated as said first slide is moved transversely across said base plate.

5. In combination with an engraving machine having pantograph arms carrying a copy stylus and a cutting tool, a device for translating a straight line legend into an arcuate or circular engraving on a work piece, which comprises a base plate adapted to be mounted on the bed of said engraving machine, a straight line master copy of fixed length, a slide arranged for transverse slidable movement on said base plate, a second slide adjustably mounted for longitudinal movement on said first slide, a work table rotatably mounted on said second slide and carrying the work piece thereon, manual means for moving said first slide transversely on said base plate including a transverse rack, a manually rotated operating shaft having a pinion thereon travelling in said rack, and a linkage for adjustably varying the transverse movement of said first slide with respect to said master copy, and a friction bar for engaging said work table and providing a friction line along which said work table may be rotated as said first slide is moved transversely across said base plate.

6. In combination with an engraving machine having pantograph arms carrying a copy stylus and a cutting tool, a device for translating a straight line legend into an arcuate or circular engraving on a work piece, which comprises a base plate adapted to be mounted on the bed of said engraving machine, a straight line master copy of fixed length, a slide arranged for transverse slidable movement on said base plate, a second slide adjustably mounted for longitudinal movement ,on said first slide, a work table rotatably mounted on said second slide and carrying the work piece thereon, manual means for moving said first slide transversely on said base plate including a transverse rack, a manually rotated operating shaft having a pinion thereon travelling in said rack, a linkage for adjustably varying the transverse movement of said first slide with respect to said master copy, and a friction bar for engaging said work table and providing a friction line along which said work table may be rotated as said first slide is moved transversely across said base plate, a brake for preventing rotation of said work table, and means for releasing said brake while moving said first slide transversely.

7. In combination with an engraving machine having pantograph arms carrying a copy stylus and a cutting tool, a device for translating a straight line legend into an arcuate or circular engraving on a work piece, which comprises a base plate adapted to be mounted on the bed of said engraving machine, a straight line master copy of fixed length, a slide arranged for transverse slidable movement on said base plate, a second slide adjustably mounted for longitudinal movement on said first slide, a work table rotatably mounted on said second slide and carrying the work piece thereon, manual means for moving said first slide transversely on said base plate including a transverse rack, a manually rotated operating shaft having a pinion thereon travelling in said rack, a linkage for adjustably varying the transverse movement of said first slide with respect to said master copy, and a friction bar for engaging said work table and providing a friction line along which said work table may be rotated as said first slide is moved transversely across said base plate, a brake normally engaging said work table and preventing its rotation, and means on said operating shaft for releasing said brake without moving said first slide transversely.

8. In combination with an engraving machine having pantograph arms carrying a copy stylus and a cutting tool, a device for translating a straight line legend into an arcuate or circular engraving on a work piece, which comprises a base plate adapted to be mounted on the bed of said engraving machine, a straight line master copy of fixed length, a slide arranged for transverse slidable movement on said base plate, a second slide adjustably mounted for longitudinal movement on said first slide, a work table rotatably mounted on said second slide and carrying the work piece thereon, manual means for mov- 1ng said first slide transversely on said base plate including a transverse rack, a manually rotated operating shaft having a pinion thereon travelling in said rack, a linkage for adjustably varying the transverse movement of said first slide with respect to said master copy, and a friction bar for engaging said work table and providing a friction line along which said work table may be rotated as said first slide is moved transversely across said base plate, a brake normally engaging said work table and preventing its rotation, and means for releasing said brake without moving said first slide transversely including a pivoted lever and a cam on said operating shaft for engaging said pivoted lever.

9. In combination with an engraving machine having pantograph arms carrying a copy stylus and a cutting tool, a device for translating a straight line legend into an arcuate or circular engraving on a work piece, which comprises a base plate adapted to be mounted on the bed of said engraving machine, a straight line master copy of fixed length, a slide arranged for transverse slidable movement on said base plate, a second slide adjustably mounted for longitudinal movement on said first slide, a work table rotatably mounted on said second slide and carrying the work piece thereon, manual means for moving said first slide transversely on said base plate including a transverse rack, a manually rotated operating shaft having a pinion thereon travelling in said rack, a linkage for adjustably varying the transverse movement of said first slide with respect to said master copy, and a friction bar for engaging said work table and providing a friction line along which said work table may be rotated as said first slide is moved transversely across said base plate, a brake normally engaging said work table and preventing its rotation, means for releasing said brake including a pivoted lever, a cam on said operating shaft, and lost motion means provided on said operating shaft for releasing said brake without moving said transverse slide.

References Cited in the file of this patent UNITED STATES PATENTS 159,488 Wight Feb. 2, 1875 790,172 Benton May 16, 1905 1,874,046 Jonsson Aug. 30, 1932 1,889,660 Horner Nov. 29, 1932