US3662467A

US3662467A - Engraving apparatus

Info

Publication number: US3662467A
Application number: US85666A
Authority: US
Inventors: Richard W Schmutzler; Merton E Scott; Kenneth J Page; Edgar S Van Buren
Original assignee: SCOTT MACHINE DEV CORP
Current assignee: Scott Machine Development Corp; SCOTT MACHINE DEV CORP
Priority date: 1970-10-30
Filing date: 1970-10-30
Publication date: 1972-05-16
Anticipated expiration: 1989-05-16
Also published as: CH528377A; DE2153480C3; FR2110094A5; AT312391B; DE2153480A1; DE2153480B2

Abstract

A pantograph engraver workpiece clamp having a pair of clamping arms each pivotally mounted on respective traveling nuts carried on oppositely threaded portions of a clamping screw, with springs biasing the clamp arms toward a reference direction and the arms extending past scale markings, so that a tapered workpiece may be easily clamped with its centerline aligned relative to an engraving tool reference position and relative to a line of engraving type.

Description

United States Patent Schmutzler et al.

[451 May 16,1972

[54] ENGRAVING APPARATUS [72] Inventors: Richard W. Schmutzler; Merton E. Scott; Kenneth J. Page; Edgar S. Van Buren, all

of Walton, N.Y.

[73] Assignee: Scott Machine Development Corporation,

Walton, N.Y.

[22] Filed: Oct. 30, 1970 [21] Appl.No.: 85,666

[52] US. Cl ..33/25 B [51] Int. Cl v ..B43l 13/10 [58] Field oi'Search ..90/l3.1; 33/213,25

[56] References Cited UNITED STATES PATENTS 3,l7l,207 3/1965 Wormser ..33/23 C 2,565,821 8/1951 Makishima ..33/23 R Primary Examiner-Harry N. Haroian A!torneyRichard G. Stephens [57] ABSTRACT A pantograph engraver workpiece clamp having a pair of clamping arms each pivotally mounted on respective traveling nuts carried on oppositely threaded portions of a clamping screw, with springs biasing the clamp arms toward a reference direction and the arms extending past scale markings, so that a tapered workpiece may be easily clamped with its centerline aligned relative to an engraving tool reference position and relative to a line of engraving type.

8 Claims, 8 Drawing Figures PATENTEDMAY 16 I972 3,662,467

SHEET 2 UF 3 FIG. lb

PATENTEUMAY 16 1972 862,467

sum 3 OF 3 FIGZQ FIG. 2b

the probability of theft of such articles and greatly increases the probability of their return when they are lost or misplaced. A variety of pantograph engravers are available for engraving symbols and the like on various forms of jewelry, on flat name tags and signs and the like, and even on bowling balls, but all of those of which we are aware are generally unsatisfactory, for use by a relatively unskilled sporting goods clerk, for example, to engrave names or initials and the like on tapered items such as skis, ski poles and golf clubs.

A pantograph engraver commonly includes a pantograph linkage having a first pivot fixed relative to a machine base, a second pivot carrying a motor-driven drill-like engraving tool, and a third pivot carrying a stylus. Movement of the stylus along grooves in a series of master type pieces moves the engraving tool in a like pattern on a workpiece fixed to the machine base, usually with a decrease in scale. The angle at which a line of engraved symbols will extend along a workpiece depends upon the angle established between the workpiece and the direction at which the master type extends while the engraving is done. Typical pantograph engraving machines used for the engraving of rectangular signs and name plates are provided with workpiece clamps which readily orient the various sides of a rectangular plate workpiece perpendicular to and parallel to the direction at which the master type extends. Most pantograph engravers are quite unsuitable for engraving non-rectangular articles, however, since they will not align such an article to a desired angle. Because skis ordinarily taper in width, from one width near the front end to a different width near the rear end, a simple workpiece vise on an engraving machine will not engage the sides of a ski so as to hold it securely without damaging it, and it will not align the ski with a known and definite relationship to the master type line direction. Because skis are provided in a variety of widths with a variety of tapers, it is not practical to provide spacers or the like to adapt a given ski to an ordinary vise-like workholder. Though the sides of a ski taper slightly toward each other, it is ordinarily desired, for the sake of appearance, that an engraved line of symbols extend across the ski in a direction perpendicular to the centerline of the ski, rather than in a direction perpendicular to either side of the ski. It is also regarded important, for sake of appearance, that the line of symbols be centered. It is absolutely necessary that a ski be held securely without inadvertent or accidental movement while it is engraved, or else the lettering may be ruined, ruining the ski to some extent. One object of the present invention is to provide a pantograph engraving machine which will securely hold tapered workpieces, such as skis, in a desired position relative to the master type line direction, so that a line of engraving may extend perpendicular to a centerline located in between two tapering sides of the workpiece. On very narrow articles, such as the shafts of ski poles or golf clubs, it is frequently necessary that the name, address or other wording desired to be engraved extend in the direction of the centerline of the article, rather than perpendicular to the centerline, and another object of the invention is to provide improved engraving apparatus which will also accomplish that type of engraving.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts, which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:

FIG. 1 is a plan view of an engraving machine constructed in accordance with the invention with the pantograph portion of the machine omitted in order to afford a better view of the improved workpiece clamping means, which is shown in FIG. I clamping a portion of a ski.

FIG. la is an elevation view taken along lines lala in FIG. 1, with the pantograph portion of the machine shown in place.

FIG. 1b is an elevation view taken along lines lb-lb in FIG. 1.

FIG. 1c is a cross-section view taken at lines lc- 1c in FIG. 1.

FIGS. 2a-2d are diagrammatic geometrical views useful in understanding limitations of prior art apparatus and the operation and advantages of the present invention.

The nature of the problems involved may be better understood by reference to the diagrammatic views of FIGS. 2a and 2b. Referring first to FIG. 2a, assume that A and B are jaws of a simple vise, with screw C threaded through movable jaw A and passing through unthreaded stationary jaw B, which is longitudinally fixed on shaft C, so that rotation of crank handle D moves jaw A toward or away from stationary jaw B. E represents the reference position of a cutting tool. As crank D is turned to draw jaw A toward jaw B sufficiently to grasp workpiece W between the jaws, it will be apparent that workpiece W will be moved so that the centerline YY of the workpiece will be laterally displaced from the reference position E of the cutting tool, by amounts dependent upon both the average width and the taper of workpiece, i.e. the angle between sides W and W of the workpiece.

Assume now instead that the vise of FIG. 2a is a self-centering vise in which screw C does not move endwise, and that the ends of the screw are oppositely threaded, so that rotation of screw C moves jaws A and B in opposite directions. It will be seen that tightening the jaws of such a vise will not move the centerline Y-Y of the workpiece away from the cutting tool reference position E. However, the corners A, and B of the jaws will contact the workpiece first, and if the vise is further tightened, on a wooden article such as a ski, for example, the jaws will bite into and deform the workpiece, tending to form notches of the type indicated in dashed lines at H and .I in FIG. 2a. If all skis had the same taper, one could avoid such damage to skis by providing appropriate shapes for the faces of the jaws, such as those indicated by dashed lines at K and L in FIG. 2a, but since the tapers of various skis differ significantly, and because it is usually desirable that an engraver be useful for various articles other than skis, such a technique offers no solution. Also, because a ski is ordinarily a long relatively heavy article, it is necessary that it be held with substantial force while it is engraved. It is necessary that the force be widely distributed in order that the gripping jaws not bite into the sides of the ski. If jaws A and B in FIG. 2a are given substantially greater width, so that they extend further along the length of a ski workpiece, it will be seen that they will tend to bite deeper into the sides of the ski.

In order to solve the above problems, the engraving machine of the present invention provides a pair of vise jaws which are each pivotable about a vertical axis. One would ordinarily assume that the use of pivoting jaws would tend to destroy the self-centering action of the centering screw unless the engraving were done in the immediate vicinity of the centering screw, since pivoting jaws allow a workpiece to be clamped in any of a wide variety of angular positions, and it is difficult or impossible to engrave in the vicinity of the centering screw. For example, FIGS. 21: and 2c each diagrammatically illustrate a workpiece clamping means comprising a screw C threaded in opposite directions on opposite ends, with a pair of traveling nuts M and N threaded on the screw, and with a pair of vise jaws A and B each pivotally attached to a respective one of the traveling nuts. FIG. 2b shows an ideal condition where the workpiece is centered adjacent the cutting tool reference position E when the vise is tightened. However, such an arrangement can clamp the workpiece W just as well in an extreme variety of other angular orientations,

one of which is shown in FIG. 2c, where the workpiece centerline will be seen to be substantially displaced from the cutting tool reference position E, and the only portion of the workpiece which is centered on the machine reference axis Y-Y will be seen to be that portion lying under screw C, where it is difficult for a tool to be arranged to engrave, and even if so arranged, the engraving would not necessarily be perpendicular to the workpiece centerline.

However, in accordance with the invention, by the simple expedients of lengthening the pivotal clamping arms 20 that they extend past the cutting .tool position, and providing means by which the remote ends of the pivotal arms may be held centered relative to the machine axis while they are tightened, all of the above-mentioned problems are overcome. In FIG. 2d pivotal clamping arms A and B are shown extended in length past cutting tool reference position E, to where a face of each pivotal arm passes a stationary graduated scale S having graduated scale marks extending in opposite directions on both sides of a zero mark situated on the machine axis. If arms A and B are held at equal distances from the zero mark while screw C is rotated to clamp the workpiece, it will be seen that the workpiece will be centered on machine axis Y-Y at its upper end, and because traveling nuts M and N automatically center the workpiece under the screw C, the intermediate portion of the workpiece in the vicinity of cutting tool reference position E will also be accurately centered.

Referring now to FIGS. 1 and 1a to 1d, the specifically disclosed embodiment of the improved engraver will be seen to include four

legs

10,10 having rubber padded feet 11 which support a rigid machine base comprising side bars 12 and 13, front cross-bar 15, and a rear platen 14 upon which a line of master type may be fastened. In FIG. 1 the line of type is shown as comprising five pieces of type carrying the letters S, C, O, T and T, in somewhat enlarged form. In FIG. 1a the line of master type is shown at 58 clamped against raised edge 14a of platen l4, and edge 140 carries scale markings in opposite directions from axis Y-Y to allow a word or name to be easily centered relative to axis Y-Y An extrusion bar 65 having a cross-section evident from FIG. 1a butts against and clamps the pieces of type against edge 14a.

Thumbscrews

66,66 passing through bar 65 thread into bar 67 which extends across the machine below a portion of platen 14, as shown in FIG. 10, so that tightening thumbscrews 66 fixedly clamps bars 65 and 67 against the top and a bottom portion of platen 14. The center one of the three thumbscrews 66 passes through a portion of a slot 70 through platen 14, slot 70 being approximately centered on axis YY and extending parallel thereto.

Clamps

68,68 slidably mounted on bar 65 may be fixed in place by tightening

thumbscrews

69,69 to hold the type centered. The line of master type comprises a series of plates having individual letters and/or numerals cut as grooves into the plates. As stylus 27 is moved within the grooves, motor-driven engraving tool 56 follows a similar path on a reduced scale.

A pair of hinge blocks 72 and 73 are mounted atop opposite ends of front cross-bar l5, and hinge bar 76 extends between

block

72 and 73, being pivotally or rotatably mounted between the blocks. Plate 42 is slidably mounted on hinge bar 76, and thus adjustable to various lateral positions along bar 76, and thumbscrew 74 allows plate 42 to be clamped in a desired lateral position on bar 76. The pantograph linkage, which has a construction well known in the art, includes a pivot post 52 mounted in hole 42a (FIG. 1) of plate 42. Reference mark 15a (FIG. 1) on bar 15 allows plate 42 to be readily clamped on bar 76 so that hole 42a is centered on machine axis Y-Y. If a line of engraving is intended to extend lengthwise along the ski and to be centered on the centerline of the ski, plate 42 is clamped on bar 76 with the edge of plate 42 aligned with reference mark 15a, so that the front pivot point 42a of the linkage is centered on axis Y-Y. If the line of engraving is intended to extend lengthwise along the ski, but to be offset laterally from the centerline of the ski, plate 42 is clamped on bar 76 either to the left or to the right of the position shown in FIG. 1.

Pantograph arm 50 mounted atop pivot post 52 is pivotally connected to arm 47 by pivot pin 51, and pivotally connected to arm 44, the latter pivotal connection being hidden by motor 55 in FIG. 1a. Motor 55, which ordinarily comprises a universal motor, is bodily carried on arm 47, and supplied with electrical power via flexible cord 57, only a portion of which is shown. Arms 44 and 47 are also pivotally connected at opposite ends of bar 45 by

pivot pins

48 and 49. The left end of arm 44 in FIG. 1a carries stylus 27, which is slidably mounted in collar 53 attached to arm 44, with coil spring 54 interconnecting stylus 27 and collar 53. As handle 41 on the end of arm 44 (which handle also acts as a guard) is raised or lowered with or against the force of spring 54, with collar 53 sliding upwardly or downwardly on stylus 27, the entire pantograph linkage pivots about the axis of hinge bar 76, raising or lowering motor 55, so that engraving bit 56 rotated by motor 55 is raised out of engagement with or lowered into engagement with workpiece 40. A collar 75, which is shown in cross-section in FIG. 1a surrounds a portion of engraving bit 56, which extends down past the collar for a distance corresponding to the desired depth of cut. Collar 75 presents a widened lower surface which rides against the workpiece when the bit has entered to the selected depth, and hence collar 75 acts as a depth stop. Motor 55 is threaded through link 47 and is clamped with thumbscrew 79. Depth stop collar 75 is threaded to the portion of motor 55 which extends beyond link 47. Collar 75 is clamped by tightening against link 47. The workpiece 40 is clamped so its upper face, which is tobe engraved, lies at a vertical level defined by the bottom faces of front cross-bar 15 and platen 14, which level corresponds to the level of the upper faces of side bars 12 and 13, and the level of the upper faces of pivot clamping bars 27 and 38. The inner faces of clamping bars are preferably tapered, as best shown in FIG. lb, so that squeezing the workpiece between the clamping bars also forces the workpiece upwardly against bar 15 and platen 14. As the stylus is moved forwardly (rightwardly in FIG. la) or laterally (perpendicularly to the plane of FIG. 1a), engraving bit 56 is moved similarly, usually at a reduced scale.

Bearing block 21 affixed to side bar 12 by bolts 23 and bearing block 22 aflixed to side bar 13 by bolts 24 rotatably carry opposite ends of shaft 20. Shaft 20 is retained lengthwise by washers 18 and locknuts 19 on one end, and by washers l7 and locknuts 71 on the other end. Knob 25 is secured to the end of shaft 20. A U-shaped tab 26 mounted to extend from platen 14 engages an unthreaded center portion 20a of shaft 20, providing further bearing support. The portions of shaft 20 on opposite sides of section 20a are oppositely threaded, one portion having a right-hand thread and the other a left-hand thread. Traveling nut or threaded block 28 is carried on one threaded portion of shaft 20, and traveling nut or threaded block 29 is carried on the oppositely threaded portion of the shaft. As knob 25 is rotated in one direction it will be seen that blocks 28 and 29 will be drawn together, while rotation in the other direction will spread apart the two blocks. The blocks are positioned on shaft 20 during assembly of the machine at equal distances from a center point of shaft 20 at the unthreaded portion 20a, and as the blocks are driven together or spread apart by rotation of knob 25 in one direction or the other the two blocks always lie at equal distances in opposite directions from the center point of shaft 20 at 20a. The center point of shaft 20 at 20a and the center mark of scale 16 (FIG. 1) define a machine centerline Y-Y. Master-type centering scale 14a (FIG. 1) on platen l4 and reference line 15a on bar 15 are so positioned that the cutting tool reference position, which is diagrammatically shown at E in FIGS. 2a-2d, falls on the machine centerline Y--Y.

As well as its threaded horizontal bore through which screw 20 passes, block 29 (FIG. 1c) includes a two-diameter vertical bore having an upper portion 29a and a smaller diameter lower portion 29b connected by a countersunk section adapted to receive the head of flat head machine screw 63,

Insane with the flat head of screw 63 lying below screw 20. Screw 63 extends downwardly from block 29 through pivot bushing 64, which extends through a vertical bore through clamping arm 38, and washer 65 and nut 66 hold bushing 64 tightly against block 29. Thus it will be seen that pivot arm 38 may pivot about the vertical axis of bore 29a. The axis of vertical bore 290 intersects the axis of the horizontal threaded bore through block 29. While pivot bar 38 is thus arranged to pivot in a horizontal plane about the vertical axis of bore 290, it is biased toward a straight-ahead reference position parallel to side bars 12 and 13 by wire spring 31, one end of which is fixedly fastened to bar 38 by means of washer 34 and screw 35, and the other end of which extends into a hole in block 29. Pivot arm 37 is pivotally mounted on threaded block 28 in the same manner in which arm 38 is mounted on block 29, and arm 37 is similarly biased to a straight-ahead position by spring 30. In FIG. 1 the workpiece 40 is shown with parallel sides, or no taper, for ease of illustration, although, as stated above, a principal object of the invention is to allow the engraving of workpieces which do not have parallel edges.

Pivot bars 37 and 38 between which the workpiece is grasped, both extend for substantial distances on both sides of their respective pivot axes, as illustrated in FIG. 1, where the pivot bars are shown extending to slightly beyond front crossbar 15 and slightly beyond the rear edge of platen 14, so that the pressure applied to the sides of the ski is widely distributed along a substantial length of the ski, thereby allowing pivot bars 37 and 38 to securely grip the ski without biting into its sides or edges.

Because traveling nut blocks 28 and 29 are centered equal distances from machine centerline YY in FIG. la, it will be apparent that the portion of ski 40 lying under shaft will be accurately centered on axis YY when knob is tightened to clamp the ski. However, it is possible for the pivot bars to be tightened so that the portion of the ski then lying adjacent the engraving tool does not then lie centered on machine axis Y Y. In order to accurately center the lettering on the ski, it is necessary that the ski be centered on machine axis YY where the ski lies under the engraving tool. To insure the centering of that portion of the ski, scale 16 is provided on front cross-bar 15, with a zero center mark of scale 16 situated on axis YY, and with equal graduations extending along the scale on opposite sides of the zero or center mark. If the front end of the ski is held centered so that its edges lie equal distances from the center mark on scale 16 while knob 25 is turned to tighten the pivot bars, the ski then will be locked in position so that it is centered on machine axis YY at two different places along its length, one place being adjacent scale 16 and the other being adjacent shaft 20. If the ski sides are straight, the centering of the ski at those two places then will also guarantee that the ski is centered in the area of the engraving tool, no matter the width of the ski or how the ski tapers.

While the line of type is shown in FIG. 1 as being aligned parallel to the axis of lead screw 20 and perpendicular to axis YY, it will be apparent at this point that one or more lines of type may be aligned so as to extend parallel to axis Y-Y and perpendicular to lead screw 20, so that wording may be made to extend along rather than across a ski or similar workpiece, and as mentioned above, varying the position at which plate 42 is clamped on hinge bar 76 allows the lateral position of such vertical lines of working to be adjusted.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained, and since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not a limiting sense.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In an engraving machine having a base, a pantograph linkage pivotally attached to said base, an engraving tool and a stylus carried on said pantograph linkage, and means for mounting a pattern on said base for traversal of said pattern by said stylus, the combination of workpiece clamping means comprising a lead screw rotatably mounted on said base, said lead screw having first and second portions threaded in opposite directions, first and second traveling nut means carried on said first and second portions, respectively, of said lead screw, first and second workpiece engaging arms pivotally mounted on said first and second traveling nut means, respectively; and scale means carried on said base for indicating pivotal movement of said workpiece engaging arms from a reference direction.

2. A machine according to claim 1 having spring means for biasing each of said workpiece engaging arms to substantially said reference direction.

3. A machine according to claim 1 in which said lead screw extends in a second direction perpendicular to said reference direction.

4. A machine according to claim 1 in which said scale means extends perpendicularly to said reference direction.

5. A machine according to claim 1 wherein said pattern comprises a plurality of alphanumeric characters aligned relative to each other to extend along a line, and wherein said machine includes means for clamping said pattern to said base to that said line of said characters extends parallel to said lead screw.

6. A machine according to claim 1 wherein said pattern comprises a plurality of alphanumeric characters aligned relative to each other to extend along a line, and wherein said machine includes means for clamping said pattern to said base so that said line of said characters extends perpendicularly to said lead screw.

7. A machine according to claim 1 having means for adjustably shifting the position at which said pantograph linkage is pivotally attached to said base in a direction parallel to the axis of rotation of said lead screw.

8. A machine according to claim 7 having reference mark means on said base for adjusting the position at which said pantograph linkage is pivotally attached to said base to a reference position.