US2307185A

US2307185A - Manufacture of the cap portions of typographical slug casting molds

Info

Publication number: US2307185A
Application number: US330440A
Authority: US
Inventors: George W Allison
Original assignee: Mergenthaler Linotype GmbH
Current assignee: Mergenthaler Linotype GmbH; Mergenthaler Linotype Co
Priority date: 1940-04-19
Filing date: 1940-04-19
Publication date: 1943-01-05
Anticipated expiration: 1960-01-05

Description

Jan. 5, 1943; v a. w. ALLlSON MANUFACTURE OF THE GAP PORTIONS OF TYPOGRAPHICAL SLUG CASTING MOLDS Filed April 19, 1940 ll Sheets-Sheet l mam Fcg' .2.

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Jan. 5, 1943. G. w. ALLISON MANUFACTURE OF THE CAP'PORTIONS OF TYPOGRAPHICAL SLUG CASTING MOLDS Filed April l9, 1 940 11' Sheets-Sheet-3 .INVENTOR I ATTOR 15y:

Jan. 5, 1943. e. w. ALLISON 2, 3Q7,185

MANUFACTURE OF THE GAP? PORTIONS OF TYPOGRAPHICAL SLUG CASTING MOLDS Filed April 19, 1940 11 Sheets-Sheet 4 IN VENTOR A TTOR EYS Jan, 5, 1943.

M ANUFACTURE OF THE GAP PORTIONS OF Filed April 19, 1940 G.jW. ALLISON TYPOGRAPHICAL SLUG CASTING MOLDS 11 Sheets-Sheet 5 v 11v VENToR 5 70? Jan. 5, 1943.

MANUFACTURE OF CAP PORTIONS OF TYPOGR Filed April e. w. ALLISON APHICAL sum CASTINGMOLDSI 19, 1940 1,1 Sheets-Sheet 7 HHH ' 11v VENTOR A TTOR YS 7 Jan. 5, 1943. e. w. ALLisoN 2,307,185

MANUFACTURE OF THE GAP PORTIONS OF TYPOGRAPHICAL SLUG CASTING MC JLDS Filed April 19, 1940 11 Sheets-Sheet 8 I I I n I I I IN VENTOR 1943. G. w. ALLISON 2,307,185

MANUFACTURRCF THE GAP PORTIONS "0F TYPOGRAPHICAL sum CASITINGYMOLDS Filed April 19, 1940 311 Sheets-Sheet 9 sq I /06 I04 w 34 v k I AINVE'NTOR HbW I ATTOR Jan. 5, 1943. I 'e .w.ALLlsoN MANUFAC' JIURE OF THE CAP PORTIONS OF TYPOGRAPHICAL SLUG CASTING MOLDS Filed April 19, 1940 11 Sheets-Sheet 10' INVENTOR I AaTURNZY;

Patented Jan. 5, 1943 MANUFACTURE OF THE CAP PORTIONS F TYPOGRAPHICAL SLUG CASTING MOLDS George W. Allison, St. Albans, N. Y., assignor to Mergenthaler Linotype Company, a corporation of New York Application April 19,

23 Claims.

This invention relates to the manufacture of the cap portions of molds employed in typographical slug casting machines. In such machines, the mold slot or cavity is usually defined by a body portion, a cap portion, and a pair of intermediate liners, the latter being readily interchangeable with other liners to vary the dimensions of the slot according to the size of the slug to be cast. In casting slugs of the larger sizes (14 pt. or over), the cap portion of the mold is ordinarily formed with fore-and-aft grooves to produce slugs of the so-called skeleton type, i. e., slugs having an overhanging character bearing portion supported by vertical ribs cast on one face of the body portion (see for example the Sytz U. S. Patent No. 1,528,278). The various parts of the mold are made from steel which has been case-hardened to prevent distortion or warping thereof during the alternate heating and cooling to which they are subjected during successive casting operations. In addition, to aid in the ejection of the slugs from the mold, the walls of the grooves are formed at compound angles so that the vertical ribs cast in the grooves taper both in height and Width. During the casehardening operation, however, a certain amount of distortion takes place in the mold cap, and for this reason the grooves are first roughened out before hardening and then ground after hardening to bring them to their final required dimensions.

Heretofore, the roughing out of the grooves has been efiected by two milling operations, and the subsequent grinding operation by a surface grinder. During the first milling operation, a series of properly spaced V-shaped cutters are run through a mold cap blank to create a series of correspondingly shaped slots having a depth approximately .005" less than that required and a width approximately .010" less than the width of the narrowest end of the finished grooves. Thereafter, a second series of wider but similarly shaped cutters are run part way through the slots formed by the first, milling operation to increase the width thereof at one end to the point where they are approximately .010" less than the width of the widest end of the finished grooves. While this arrangement for roughing out the grooves has been practiced for a great many years, it is nevertheless slow, costly, and incapable of producing uniform mold caps. For'example, unless extreme and painstaking care is exercised by the operator, the second series of cutters may be run too far through the initially formed grooves, in which case the blank is ruined.

1940, Serial No. 330,440 (o1. 29 14s) On the other hand, if the second series of cutters is not run through the initially formed grooves far enough, the thickness of the shoulders or humps which in any case remain along the side walls (where the wider cutters worked themselves out of the initially formed grooves) is frequently greater than the depth of hardening, with the result that when the cap is subjected to the grinding operation to bring the grooves to the proper size and these humps or shoulders are so removed, there are uncovered along the side Walls of the finished grooves soft spots which ultimate 1y lead to distortion or warping of the core members defined by the grooves and to consequent interference with the ejection ofthe slugs. Furthermore, even though the operator is careful to run the second series of gang cutters just the right distance through the initially formed grooves, the presence of the humps or shoulders on the side walls is objectionable, in that, when they are removed, the depthof hardening along the walls of the finished grooves is not uniform, in which case distortion or warping results although not to the same extent that it does when soft spots are uncovered. In'addition, the above described arrangement is objectionable because the extra grinding required to remove the shoulders or humps adds greatly to the cost of the I finished product, this being true since such grinding must be accomplished very slowly in order to prevent burning or softening of the walls of the grooves.

The present invention aims to overcome the above and other difiiculties arising in the old practice and contemplates roughing out the grooves in the exact shape desired but slightly under the dimensions of the finished grooves. In this Way, none of the blanks is ruined, .the cost of the subsequent grinding operation is greatly reduced, and th walls of the finished grooves are hardened to a uniform depth.

In carrying out the invention, the roughing out operation is accomplished by means of a band saw having a blade slightly thinner than the width of the rear or narrowest end of the finished grooves. In so roughing out the grooves, two saw cuts are made in the bottom or casting face of the blank for each groove. Thus, first one series of cuts are made in the blank at an angle which accords with the compound angle of one of the side walls, and thereafter a second series of cuts are made at an angle which accords with the compound angle of the other side wall of the finished grooves. The spacing of these cuts and the depth thereof are such that they will produce in the blank a series of grooves of the exact shape desired but slightly under the final required dimensions. Due to the thinness of the saw blade, however, each pair of cuts is separated by a small wedge-shaped piece of stock which subsequently is removed by means of a punch press or the like.

After the grooves have been thus roughed out, the blank is milled in the usual manner to form the customary aligning lip on the front face thereof, after which it is case-hardened and then ground to the final required dimensions.

The grinding of the grooves is effected by means of a modified surface grinder having an abrasive wheel which is so dressed that the width of its peripheral face is slightly less than the width of the narrowest end of the finished grooves and whose side faces diverge from the peripheral face at angles which accord with the vertical angles of the side walls of the finished grooves. The blank is secured to the base of the supporting table with the roughed out grooves facing upwardly and extending parallel with the peripheral center line of the wheel. Prior to the grinding operation, the blank is adjusted to bring the longitudinal center line of one or another of the grooves in exact alignment with the peripheral center line of the wheel. Then, while the blank supporting table is being moved back and forth beneath the wheel to grind the groove to its final desired depth, the blank is rotated about a fixed axis through predetermined angles in a horizontal plane, first in one direction to grind one of the side walls of the groove, and then in the opposite direction to grind the other side wall of the groove, so as thus to bring the groove to its final required dimensions. After the roughed out groove thus selected has been ground, the remaining roughed out grooves are ground to their final required dimensions in like manner, the blank being adjusted each time to bring the longitudinal center line of the groove to be ground into exact alignment with the peripheral center line of the wheel.

For a more complete description of the invention, reference may be made to the accompanying drawings. In these drawings, however, the invention has been shown merely in preferred form and by way of example, but obviously many changes and variations may be made therein and in its mode of application which will still be comprised within its spirit, and it is to be understood, therefore, that the invention is not limited to any specific form or embodiment, except insofar as such limitations are specified in the claims.

Referring to the drawings:

Fig. 1 is a front elevation of a mold cap blank;

Fig. 2 is a plan view showing the bottom or casting face thereof;

Fig. 3 is a. front elevation of a mold cap blank after the sawing operation and before the removal of the stock from between each pair of cuts which define the roughed out grooves;

Fig. 4 is a bottom plan view of the blank shown in Fig. 3;

Fig. 5 is a front elevation of a mold cap blank after the removal of the stock from between the cuts which define the roughed out grooves;

Fig. 6 is a sectional view taken along the line 6--6 of Fig. 5;

Fig. '7 is a bottom plan view of the blank shown in Fig. 5;

Fig. 8 is a front elevation of a finished mold cap;

Fig. 9 is a sectional view taken along line 9-9 of Fig. 8;

Fig. 10 is a bottom plan view of the finished mold cap shown in Fig. 8;

Fig. 11 is a plan View of a saw unit adjusted to cut a slot which defines one of the side walls of the roughed out grooves;

Fig. 12 is a plan view of a saw unit adjusted to out a slot which defines the other side wall of the roughed out grooves;

Fig. 13 is a front elevational view of the saw unit shown in Fig. 11;

Fig. 14 is a front elevational view of the saw unit shown in Fig. 12;

Fig. 15 is an end view of one of the saw units with portions broken away to more clearly show the arrangement of parts;

Fig. 16 is a sectional view taken along line i6l6 of Fig. 11;

Fig. 17 is a sectional view taken along line H-ll of Fig. 11;

Fig. 18 is a sectional view l8l8 of Fig. 11;

Fig. 19 is a schematic view showing the first step to be performed when grooves are to be roughed out simultaneously in a plurality of blanks;

Fig. 20 is a schematic view showing the second step to be performed when grooves are to be roughed out simultaneously in a plurality of blanks;

Fig. 21 is a schematic view showing the third step to be performed when grooves are to be roughed out simultaneously in a plurality of blanks;

Fig. 22 is a plan view of the punching device employed to remove the stock from between each pair of saw cuts which define a roughed out groove;

Fig. 23 is a front elevational view of the device shown in Fig. 22;

Fig. 24 is a side elevational view of the device shown in Fig. 22;

Fig. 25 is a detail front elevational view showing the manner in which the stock is removed from between each pair of saw cuts which define a roughed out groove;

Fig. 26 is a detail view in section which also shows the manner in which the stock is removed from between each pair of saw cuts which define a roughed out groove;

Fig. 27 is a plan view of the fixture employed in combination with a surface grinder for grinding the grooves to their final required dimension as well as the fixture employed in dressing the wheel of the grinder;

Fig. 28 is a side elevation of the apparatus shown in Fig. 27;

Fig. 29 is a detail view showing the instrumentality employed to locate a groove to be ground in alignment with the grinding wheel; and

Fig. 29* is a sectional view taken along line 29--29 of Fig. 29.

In practice, the cap portion of molds used in casting slugs of the larger sizes (14 pt. or over) are made from blanks 30 (Figs, 1 and 2) of soft or unhardened steel. As stated heretofore, this cap portion of the mold must be formed with a series of fore-and-aft grooves 3| (Figs. 8 and 10) which taper throughout their length both in height and width.

In accordance with the present invention, the grooves 3| are first roughed out in the exact shape required but slightly undersize by making a pair of saw cuts 32 (Figs. 3 and 4) in the bottaken along line tom of casting face 33 of the blank for each groove to be formed. Each such pair of saw cuts 32, however, leaves a small wedge-shaped piece of stock 34 which is subsequently sheared off (see Figs. and 26) to complete the roughing out of the grooves (as in Figs. 5, 6 and '7). Thereafter, the blank is milled in the manner well understood in the art to form the customary aligning lip on the front face thereof (Figs. 8, 9 and 10). The blank 30 is then case-hardened in the usual manner and finally ground to bring it to its final required dimensions.

In the present embodiment of the invention, the saw cuts 32 are effected by employing two band saw machines (Figs. 11 to 15 inclusive), each equipped with a blade 36 slightly thinner than the width of the narrowest end of the finished grooves. The blade 36 of each saw unit travels .vertically between guides 31, and it is adapted to be driven at a high rate of speed by means which are so well known in the art that a description thereof is not deemed necessary.

Each machine is adapted to present a pair of superposed blanks 3G to its blade 36 at any desired compound angle and at any desired point along their length. To the end that the blanks may-be presented to the blade 36 at any desired compound angle, each machine is equipped with a table 38 rotatably mounted on a pair of short fore-and-aft shafts 39, 40 (Fig. 15) carried by hubs 4| 42 respectively secured to the main frame of the machine. The table 38 of each machine is provided with a superstructure or fixture comprising a base plate 43, an intermediate plate 44 and a top plate 45. The top plate 45, in turn, is provided with a pair of jaws 46, 41 between which the blanks 39 are secured with their bottom or casting faces 33 positioned in front of the saw blade 36. The left jaw 46 is adjustable to accord with blanks of different lengths, and between this jaw and the adjacent ends of the blanks a gauge block 50 is interposed for purposes subsequently to appear. The clamping of the blanks 38 is effected by means of a pair of clamping screws 49 (Fig. 11) which are threaded through the fixed jaw 4! against the right ends of the blanks and a number of similar clamping screws 5| which are threaded through upstanding shoulders carried by the top plate 45 and against the outer faces of the blanks to press the casting faces 33 against stops 54, provided by the jaws 46, 4'! respectively. In addition, the blanks are clamped from above by means of a bracket 52 secured to the top plate 45 by means of a stud 52 The intermediate plate 44 is pivotally secured at its right end on a stud 58 rising from the base plate 43. In consequence, by simply swinging the intermediate plate 44 about its pivotal axis through a predetermined angle in a horizontal plane and the table 38 about its axis of rotation in a vertical plane, it is thus possible to present the superposed blanks 30 confined be tween the jaws 48, 4'! in front of the blade 36 at any desired compound angle.

The swinging movement of the intermediate plate 44 about its pivotal axis to obtain the horizontal component of the compound angle is a relatively simple operation and may be accomplished by pushing its free end by hand. The tilting movement of the table 38 to obtain the vertical component of the compound angle,'being accomplished in a vertical plane, is a more difficult operation. To efiect the adjustment of the table 38, therefore, it is provided with an angularly disposed adjusting rod 59 (see Figs. 13, 14) pivotally secured at its lower end to a bracket' 60 carried by the main frame of the machine and adjustably connected at its upper end by means of a pair of nuts 6|, 62 to a plate 63 secured to the table 38, the arrangement being such that the table may be set at any desired vertical angle by simply adjusting the nuts 6|, 62 along the rod 59.

"It is to be noted that the intermediate plate 44 of each machine, at its left end (see Figs. 11, 12) is provided with a series of holes 63 which are so located with respect to a series of similar holes 64 formed in the base plate 43 that, when the intermediate plate has been adjusted to the proper angle, one or another of the holes 63 therein align with one or another of the holes 64 in the base plate. Under these conditions, a pin 65 'need only be inserted through the aligned holes to lock the intermediate plate 44 in the position to which it has been adjusted. Likewise, a depending plate 66 secured to the front face of the table 38 (see Figs. 13, 14) is provided with a series of holes 61 which are so located with respect to a series of similar holes (not shown) formed in the front face of hub 39 that, when the table 38 has been tilted to the proper angle, one or another of the holes 61 in the plate 66 aligns with one or another of the holes in the hub 39. In consequence, by inserting a pin 69 through the aligned holes, it is thus possible to lock the table 38 in its adjusted position. In addition to the lock thus provided for the table 38. a further lock is provided in the form of a clamping stud 10 threaded into hub 4| through an arcuate slot H formed in the depending face plate 66.

As before stated, each machine is also adapted to present the blanks 30 to its blade 36 at any point along their length. To this end, the top plate 45 is slidably secured to the intermediate plate 44 so that, while it swings in a horizontal plane in unison therewith, it may be moved therealong, it being provided with a pair of T- shaped nuts 12, I3 slidably mounted in a T- shaped channel 14 formed in the intermediate plate 44. Under conditions of use, the top plate 45 is locked to the intermediate plate 44 by means of a pair of clamping studs 15, 16 which pass through apertures in the top plate 45 and have threaded engagement with the T-shaped nuts 12, 73.

The adjustment or endwise movement of the top plate 45, after the clamping studs 15, 16 have been loosened, is effected by means of a horizontally disposed cam 11 rotatably mounted on the stud 58 and provided with a handle 18 for the rotation thereof. When the top plate 45 is free to move, a counter-weight 19 secured to a rope 88 or the like, which is trained over a pulley 8| mounted on the intermediate plate 44 and secured to the top plate 45, acts to maintain a roller 82 carried by the top plate 45 at its right end tracking against the cam 11, so that when the cam 11 is rotated in one direction or another the top plate 45 moves back and forth above the intermediate plate 44. In order, however, that the top plate 45 may be quickly and accurately located at desired stations, the cam 1'! is provided with an interchangeable indexing disk 83 having a number of U-shaped peripheral notches 8-4 adapted and arranged to receive a spring-pressed plunger slidably mounted in a housing 85 carried by the intermediate plate 44. The number of notches 84 in the disk 83 preferably accords with the number of grooves to be formed in the blanks 3D, and these notches are so located or spaced that when the cam 11 is rotated to locate one or another of them in front of the plunger 85 and the plunger 85 is released to engage the same, the top plate 45 will be located at one or another of the exact positions to which it must be adjusted to insure that the slots will be cut in the blanks 30 at exactly the right places.

Moreover, each machine is adapted to advance the superposed blanks 30 against its blade 36 to form the cuts 32 therein. To this end (see Figs. 13, 14), the base plate 43 is slidably secured to the table 38 by means of

gibs

88, 89. The inand-out movement of the base plate 43 is effected by means of a hand wheel 95 secured to the front end of a fore-and-aft screw 9| threaded through a nut 92 carried by the base plate 43 (see Fig. At its ends, the screw 9| is provided with unthreaded

portions

93, 93 journalled in

bearings

94, 94 respectively, carried by the table 38, the arrangement being such that by turning the hand wheel 50 in opposite directions the base plate 43 is forced inwardly or outwardly. In cutting the slots 32 in the blanks 30, however, the depth thereof must be held to exact measurements, even though these measurements may vary for mold caps of different sizes. Accordingly, each machine is equipped with a stop which includes a banking member 96 (see Figs. 11, 12) adjustably secured to the table 38 by means of a T-shaped tongue and groove arrangement 91 and positioned so as to engage the inner end of a micrometer screw 93 threaded through a nut 99 carried by the base plate 43. By first making a rough adjustment in the position of the banking member 96 and then a final adjustment in the position of the screw 98, it is thus possible to limit the cut in the blanks to the exact depth required.

According to the foregoing arrangements, and preparatory to roughing out the grooves, one machine (see Fig. 11) is adjusted or set to accord with the compound angle of the left wall of the grooves, and the other machine (see Fig. 12) is adjusted or set to accord with the compound angle of the right wall of the grooves as viewed in the drawings. Here it is to be noted that, since the slots in each blank must be cut at the same distance in from their ends and since the superposed blanks 30 are presented to the blade at an angle, the superposed blanks must bear a predetermined lineal relationship to each other to insure that the slots in each blank will be cut at the same distance in from the ends. For example, in the machine set to cut the left wall of the groove, the uppermost blank must be disposed slightly to the left, whereas in the machine set to cut the right wall of the groove the uppermost blank must be disposed slightly to the right. In the present embodiment of the invention, this is accomplished by properly recessing the aforementioned gauge block in each machine against which the left ends of the blanks are clamped. The gauge block 50 in each machine is held to the adjustable jaw 46 by screws 43 (see Figs. 19, 20 and 21) and may be replaced as required.

Also before the cuts are made, the banking member 96 and the micrometer screw 98 are adjusted so that the depth of the slots will be approximately .0O5" short of the depth of the finished grooves. In addition, the cam 11 is rotated to bring the first of the series of notches 84 on the indexing disk 83 opposite the plunger 85 which is then released to engage the same and so locate the blanks 30 at the proper location for the first cut. Thereafter, the top plate 45 is reclamped to the intermediate plate 44, and the first cut is made in the blanks by rotating the hand wheel 90 first in one direction and then in the other direction to carry the blanks 30 inwardly and outwardly. After the first out has been so made, the top plate 45 is loosened, the plunger withdrawn from the first notch in the indexing disk 83, the cam 11 rotated to bring the second notch opposite the plunger 85 which is then released to engage the same, the top plate 45 reclamped to the intermediate plate 44, and the second cut made in the blanks 30. In like manner, the top plate 45 is adjusted step by step and the remainder of the series of cuts which define the left walls of the grooves are made in the blanks. Thereafter, the blanks are removed from the first machine and clamped in the second machine, and the series of cuts which define the right walls of the grooves are made therein in the manner explained above.

When making the second series of cuts, however, the second of each pair of cuts runs into or overlaps the first cut at the bottom of the narrowest end of the roughed out groove formed by each pair, and as a result the blade 36 instead of making a straight out through the superposed blanks 30, which is necessary to rough out the grooves to the exact shape of the finished grooves tends to bow sidewise towards the first out due to the absence of side support along that portion of the blade which overlaps the first out. While this tendency of the blade 36 to bow sidewise would have little or no tangible effect on the shape of the roughed out groove in the uppermost blank due to the small distance the blade would be unevenly supported as it traveled through this blank, it might seriously affect the shape of the roughed out groove in the lowermost blank because, in addition to the tendency of the blade to bow sidewise as it travels through the lowermost blank, its tendency to bow sidewise as it traveled through the uppermost blank would be cumulative throughout the thickness of the lowermost blank. In consequence, when roughing out grooves in superposed blanks, it has been found desirable to first cut in a single blank a series of cuts which defines one of the side Walls of the roughed out grooves, as for example the right side wall as shown in Fig. 19. Thereafter, this blank is removed from the machine and located as the lowermost blank in the other machine which, as stated heretofore, has been adjusted to make the cuts which define the left side wall of the finished groove, and a second uncut blank is positioned above it as shown in Fig. 20. After the superposed blanks 30 have been locked in position in the second machine, a series of slots are cut therein. The uppermost blank will thus be provided with the slot which define the so-called left wall of the roughed out grooves, but in the lowermost blank the roughing out of the grooves by the saw cuts will be completed, as is also shown in Fig. 21. During this latter operation, the saw blade travels in a straight line through the uppermost blank and due to the side support thus provided, its tendency to bow sidewise where it overlaps the cuts in the lowermost blank is restrained, with the result that the grooves thus roughed out by each pair of cuts in the lowermost blank are in the exact shape as that required in the finished grooves. Thereafter, both blanks are removed from the second machine, and the uppermost one which contains the single series of slots is located as the lowermost one in the first machine and an uncut blank is superposed thereon, the two locked in position, and a series of cuts made therein to complete the roughing out of the grooves in the lowermost blank and to provide the uppermost blank with a single series of cuts, as is also shown in Fig. 21. In like manner, the top or uppermost blank is removed from one machine and made the lowermost blank in the other machine each time a series of cuts is made, and in so doing the saw work on one and one-half blanks is completed during each operation.

After the saw work has been thus completed on each blank, a wedge-shaped piece of waste metal 34 remains between each pair of cuts 32 which is subsequently removed by means of a shearing machine having a cutting tool I02 reciprocally mounted above a table I03 (see Fig. 22). The table I03 is provided with a fixture comprising a base plate I04 and a stop plate I05 having an upstanding banking shoulder I 06. The cutting tool I02 is carried by a head I slidably mounted in a vertical bracket I00, and it is adapted to be moved upwardly and downwardly through a stroke of limited distance by means well understood in the art.

When removing the wedge-shaped piece of metal 34 from between each pair of saw cuts, the

blank is mounted on the stop plate I with the fiat face in which the cuts are formed bankin against the shoulder I06, with the Widest part of the wedge-shaped pieces of stock 34 facing upwardly, and with the base or bottom edge of one of the pieces of stock immediately beneath the cutting edge of the tool I02; and to aid in so locating the blank the shoulder I 06 on the stop plate I05 is provided with an indicating pointer 68 located in alignment with the cutting tool I02. Thereafter, the tool I02 is reciprocated, and as the cutting edge of the tool is thus forced downwardly through the wedge-shaped piece of stock 34 at the rear edge thereof for a limited distance, the piece is broken away (see Figs.

and 26) and ejected through the open side of the groove. In like manner, all the wedge-shaped pieces of stock are broken away one after another, the blank being moved laterally each time to bring the piece to be removed beneath the tool I02.

Upon the removal of the Wedge-shaped pieces of stock 34, the grooves thus provided are of substantially the exact shape desired but approximately .010" undersize in width and approximately .005" undersize in depth.

After the grooves have been so roughed out, the blanks are milled to provide the aligning lip on the front face thereof, then hardened, and finally ground to the requi ed d e sio s.

In the embodiment of the invention illustrated, the grinding of the grooves to the required dimensions is effected through the medium of an improved surface grinder having an abrasive wheel IIO which is mounted on a fore-and-aft spindle I I I at the front end thereof. The spindle III extends forwardly from the main frame of the machine above the narrow part of an elongated table II2 which is adapted and arranged to be moved lengthwise automatically back and forth, from left to right in Fig. 28, predetermined distances beneath the wheel. The spindle III carrying the wheel H0 is adapted and arranged to be driven at a high rate of speed and to be raised and lowered limited distances. The mechanism, employed for driving the spindle III and for raising and lowering it, as well as the mechanisms for moving the table II2 back and forth, are all well known in the art and a description thereof is not deemed necessary. The table H2 carries a fixture comprising a base plate H5, an intermediate plate I I6 and a top U-shaped slide plate III which, in turn, is provided at its opposite ends with a pair of interchangeable inverted U-shaped clamps H8, H9 between which the mold cap blank 30 is secured. During the grinding operation, the blank is positioned with the face in which the roughed out grooves are formed uppermost, the longitudinal center line of the roughed out grooves parallel with the peripheral center line of the wheel, and the narrowest end of the grooves located remote from the wheel (see Fig. 27). The rearmost clamp H0 is provided with a stop pin I20 and the U-shaped slide plate III is provided with a pair of fixed stops I2I, I22. In locating the blank 30 for the grinding operation, it is inserted beneath the inverted U-shaped clamps H8, H0 with the inner end thereof resting against the stop pin I20 and with the flat side face from which opens the narrowest end of the grooves resting against the fixed stops I2I, I22. Thereafter, a wedge-shaped member I23 is driven between the blank 30 and the U-shaped slide plate I I! to force the blank 30 upwardly against the closed end of the clamps H8, H9, after which the blank 30 is locked in fixed position by means of a pair of studs I28 which are brought to bear against a pair of intermediate toe clamps I24.

The U-shaped top plate I I? is slidably mounted on the intermediate plate H6 so that it may be moved manually forwardly and backwardly to bring any selected one of the series of grooves in the blank 30 directly beneath the wheel Iii In addition, means are provided for accurately locating the top plate II'I' so that the plane of symmetry of the groove selected will coincide with the plane of symmetry of the wheel H0, which is perpendicular to its axis (see Fig. 27), Such means, as clearly shown in Fig. 29, comprises an arm I25 pivotally mounted at its lower end on an eccentric shaft I26 and provided at its upper end with a pin I2I which projects from the face thereof. The shaft I26 is mounted in a bracket I28 secured to the intermediate plate II B at the left end thereof, and the arm I25is so positioned with respect to the wheel Ilil by means of gauge plates lit and I28 that the longitudinal center line of the pin I21 coincides with a vertical plane passing downwardly through the centroidal point of the wheel H0. The parts are so arranged that the arm I25 may be swung downwardly and forwardly to locate the pin I21 in a wider portion of the groove selected. Then when the eccentric shaft I25 is thereafter rotated, it being provided with a handle I26 for this purpose, the pin I2? is dragged rearwardly through the groove until further movement thereof is arrested by its engagement with the side walls of the groove at the narrow or rear end thereof. By this arrangement, the top slide plate II! is shifted, if necessary, as the pin I27 travels rearwardly so that its plane of symmetry will coincide with the longitudinal center line of the pin I2'1 which, as stated above, coincides with a vertical plane passing downwardly through the centroidal point of the wheel IIO. After the groove selected has been so located, the top plate III is lockedto the intermediate plate II 6 by means of clamping studs I33 and the table H2 is returned to its original position preparatory to the grinding operation to follow.

For reasons presently to appear, the intermediate plate H6 is formed on its lower face with a hub portion I35 journalled in the base plate M to provide a vertical axis about which the fixture may be rocked and which is also located in the same plane of symmetry before mentioned of the abrasive wheel H0. During the final horizontal adjustment of the mold cap blank 30, however, as above described, the grinding fixture is locked against rocking movement by means of a plunger I36, which is mounted in a fixed extension I31 of the base plate H5 and engages a notch I38 in a bracket I39 secured to the intermediate plate H6. The bracket I39 (see Fig. 27) is provided with a pair of depending stop pins I40, I II spaced apart and adapted to engage respectively the opposite sides of the plunger I36, when the latter is withdrawn from the notch I38, so as to thus limit the rocking movement of the fixture in opposite directions. To hold the plunger I36 in both its active and inactive positions, it is provided with a pair of detents I42, I83 which cooperate with a set screw I54 mounted in the fixed extension I31 of the base plate I I5.

Operation of the fixture in either direction is controlled by a hand wheel I45 secured to the outer end of a screw shaft I46, which is journalled in another extension I41 of the base plate I I5 and has a threaded engagement with a bracket member I48 secured to the intermediate plate H6.

The intermediate plate I I6 of the fixture is secured to the base plate so that it stands at an angle which accords with the bottom walls of the finished grooves between the core sections so as to permit these walls to be ground at the required angle as the table H2 is reciprocated in a horizontal plane. It will also be noted that the opposite side faces of the abrasive wheel III) are dressed at angles" which accord respectively with the vertical angles of the opposing side walls of adjacent core sections. Moreover, the axis about which the fixture is rotatable is located immediately adjacent the left side face of the mold cap through which the converging ends of the grooves open, and is adapted through the adjustment of the cap 30 in the fixture to coincide with the plane of symmetry of the respective grooves. Consequently, when the fixture is swung in one direction about its axis as far as permitted by the engagement of a stop pin I40 with the plunger I36, a side wall of one core section of the cap 30 will be brought into a position parallel with the direction of movement of the reciprocable table H2, and when it is swung in the other direction as far as permitted by the engagement of the other stop pin IliI with the plunger I36, the opposing side wall of the adjacent core section will be brought into a similar position.

It will now be seen that, by merely lowering the abrasive wheel IIO into a groove while the cap 30 is held alternatively in these two positions, first one of the side walls and then the other may be ground, as the table II2 reciprocates, at the exact compound angle and to the final dimension required. Also, that the grinding of the bottom walls of the grooves is readily accomplished by holding the wheel I I0 in its lowermost position and moving the fixture about its axis between the limitations fixed by the stop pins I40, I4I.

It frequently happens that the abrasive wheel IIO due to wear has to be redressed or replaced by another wheel that has to be dressed, and for this purpose the table H2 is equipped with another fixture which, as shown in Figs. 27 and 28, is arranged adjacent the fixture and includes an upright angular post or stanchion I56 rising from a base plate I51 secured to the table H2, and a finishing tool I58 which is mounted on a flat plate or shelf I59 fastened to the top of the stanchion I56. The stanchion I56 is connected to the base plate I51 by means of a clamping stud I60 and slot I6I arranged so as to be capable of bodily movement in a direction parallel to the axis of the abrasive wheel IIO under the infiuence of two set screws I62, I63 which are arranged to engage respectively the front and rear side faces of the stanchion I56 and which are mounted in ears I64, I65 projecting upwardly from the contiguous edges of the base plate I51. The finishing tool I58 comprises a block I66, slotted transversely in its lower face, for engagement with one or another of three track bars I61, I68, I69 and provided with a screw rod I10 which extends longitudinally therethrough and carries a diamond point I1I. The track bars I61, I68, I69 are screwed down upon the shelf I59 and arranged as best shown in Fig. 27 with the two tracks I61, I69 diverging from the opposite ends of the fore-and-aft track I69 at angles which accord respectively with the two vertical angles of the opposing side walls of adjacent core sections of the mold cap.

In setting up the fixture for the wheel dressing operation, it is first necessary that the wheel IIO be lowered to a level where its axis will be aligned horizontally with the longitudinal axis of the screw rod I10 which carries the diamond point I1I, because otherwise the beveled grinding surfaces of the wheel I I0 could not be dressed at the angles desired without first setting the position of the wheel in accordance with highly complicated computations on the part of the operator. Such alignment, as shown best in Fig. 27, is facilitated by an arm I15 pivoted at one end immediately beneath the shelf I59 on a vertical axis I16 so that it may be swung from an inactive position to a position where its free end I11 will engage the hub portion I18 of the wheel I I0 as it is lowered and thus arrest and support it at the proper level. The stanchion I56 is then adjusted in the manner above stated so as to locate the two tracks I61,I68 respectively equal distances from the opposite side faces of the abrasive wheel I III. The tool I58 may now be mounted on, say, the front track I68 and one of the beveled grinding surfaces of the wheel dressed to the proper angle by sliding the tool I58 to and fro and occasionally adjusting the screw rod I10. After this operation, the tool I58 is shifted from the front track I68 to the rear track I61 and the other beveled grinding surface of the abrasive wheel H0 is dressed in similar fashion. The tool I58 is then shifted from the rear track I68 to the fore-and-aft track I69, the screw rod I10 is adjusted to carry the diamond point I1I into contact with the peripheral edge of the wheel H0, and the tool I58 reciprocated to complete the dressing operation. It may be mentioned that the screw rod I10 is held in its different adjusted positions, as the three grinding surfaces of the wheel I ID are being dressed, by a set screw I mounted in tool I58 and engaging the rod. Also, that the shelf I59 is formed in its edge adjacent the wheel IIO with a U-shaped clearance notch I8I to accommodate that portion of the wheel III) to be dressed.

While it is preferable, as hereinbefore described, to employ two separate saw units to operat-e on the blanks in producing the two series of saw cuts which define the opposite side walls of the grooves, it is pointed out that both series of saw cuts could be produced by the use alone of one saw unit which, as shown in the drawings, is capable of being adjusted to either the'position shown in Figs. 12 and 13 or to the position shown in Figs. 14 and 15. By employing two separate units, one adjusted to one position and the other to the opposite position, the sawing operations may be performed more expeditiously and the expense of manufacture thus substantially reduced.

Having thus described my invention, what I claim is:

1. The method of producing a typographical slug casting mold cap with fore-and-aft grooves in its bottom or casting face, which method includes providing a suitable blank of soft or unhardened steel, forming in said blank grooves of the exact shape required but of slightly less than final dimensions, case-hardening the blank with the grooves as thus formed, and thereafter finishing the grooves to bring them to the final dimensions required while preserving their original shape.

2. The method of producing a typographical slug casting mold cap with fore-and-aft grooves in its bottom or casting face, said grooves tapering from the front or line-contacting face of the cap toward the rear or pot-mouth-contacting face thereof, which method includes providing a suitable blank of soft or unhardened steel, forming in said blank grooves tapered in a fore-andaft direction to the exact shape required but of slightly less than final dimensions, case-hardening the blank with the grooves as thus formed, and thereafter finishing the grooves to bring them to the final dimensions required While preserving their original shape.

3. The method of producing a typographical slug casting mold cap with fore-and-aft'grooves in its bottom or casting face, said grooves tapering from the front or line-contacting face of the cap toward the rear or pot-mouth-contacting face thereof and also tapering from the bottom or casting face of the cap toward the top face thereof, which method includes providing a suitable blank of soft or unhardened steel, forming in said blank grooves tapered in a fore-andaft direction and also widthwise to the exact shape required but of slightly less than final dimensions, case-hardening the blank with the grooves as thus formed, and thereafter finishing the grooves to bring them to the final dimensions required while preserving their original shape.

4. The method of producing a typographical slug casting mold cap with fore-and-aft grooves in its bottom or casting face, which method includes providing a suitable blank of soft or unhardened steel, roughing out the grooves in said blank by a series of saw cuts, two for each groove, and by removing the surplus stock left by such saw cuts, case-hardening the blank with the grooves as thus formed, and thereafter grinding the walls of the grooves to bring the latter to the final dimensions required.

5. The method according to claim 4, as practiced for the production of a mold cap whose fore-and-aft grooves taper from the front or line-contacting face of the cap toward the rear or pot-mouth-contacting face thereof, characterized individual groove, are

in that the two saw cuts, which define the wallsof .each individual groove, are made in the soft or unhardened steel blank at angles in exact accord with the required taper of said groove in its final ground condition.

6. The method according to claim 4, as practiced for the production of a mold cap whose foreand-af-t grooves-taper from the front or linecontacting face oft-he cap toward the rear or pot-,mouth-contacting face thereof and also taper from the bottom or casting face of the cap toward the top face thereof, characterized in that the two saw cuts, which define the walls of each made in the soft or unhardened steel blank at compound angles in exact accord with the required compound taper cf said groove in its final ground condition.

'7. The method according to claim 4, characterized in that the saw cuts are made in the soft or unhardened steel blank in two stages, first those which define one side wall of the respective grooves, and then those which define the opposite side wall of the respective grooves.

8. The method according to claim 4, as practiced for the production of a mold cap whose fore-and-aft grooves taper from the front or line contacting face of the cap toward the rear or pot-mouth-contacting face thereof, characterized in that the two saw cuts, which define the walls of each individual groove, are made in the soft or unhardened steel blank at angles in exact accord with the required taper of said groove in its final ground condition, and in that the saw cuts are made in the soft or unhardened steel blank in two stages, first those which define one side wall of the respective grooves while the blank is tilted in one direction to accord with the required angle of said side wall, and then those whichdefine the opposite side wall of the respective grooves while theblank is tilted in the opposite direction to accord with the required angle of said opposite side wall.

9. The method according to claim 4, as practiced for the production of a mold cap whose fore-and-aft grooves taper from the front or line-contacting face of thecap toward the rear or pot-mouth-contacting face thereof and also taper from the bottom or casting face of the cap thereof, characterized in which define the walls of are made in the soft or at angles in exact accord with the required taper of said groove in its final ground condition, and in that the saw cuts are made in the soft or unhardened steel blank in two stages, first those which define one side wall of the respective grooves while the blank is tilted in two different directions to accord with the required compound angle of said side wall, and then those which define the opposite side wall of the respective grooves while the'blank is tilted in the opposite two directions to accord with the required compound angle of said opposite side wall.

10. The method according to claim 4, characterized in that the removal of the surplus stock left by each groove-defining pair of saw cuts in the soft or unhardened steel blank is effected by a searing operation which severs the surplus stock from the blank in a plane represented by the depth of penetration of the saw cuts.

11. The method according to claim 4, as practiced for the production of a mold cap whose fore-and-aft grooves taper from the front or line-contactingface of thecap toward the rear or: pot-mouth-contacting face thereof, characthat the two saw cuts, each individual groove, unhardened steel blank terized in that the two saw cuts, which define the walls of each individual groove, are made in the soft or unhardened steel blank at angles in exact accord with the required taper of said groove in its final ground condition, and in that the removal of the wedge-shaped piece of surlus stock left by each groove-defining pair of saw cuts in the soft or unhardened steel blank is effected by a shearing operation exerted on the wider end of said wedge-shaped piece and which severs it from the blank along a plane represented by the depth of penetration of the saw cuts and then ejects it through the open side of the groove.

12. The method according to claim 4, characterized in that a plurality of blanks are arranged side by side out of lengthwise registry by a predetermined amount and in that the saw cuts are made for one side of a groove in all of said blanks in one operation.

13. The method according to claim 4, characterized in that the saw cuts are made in two different blanks at one operation but in two stages, first those cuts which define one side wall of the res ective grooves, and then those cuts which define the opposite side wall of the respective grooves, the saw cuts as made in one blank in the first stage being the initial cuts, and the saw cuts as made in the other blank in the second stage being the final cuts.

14:. The method according to claim 4, characterized in that a series of saw cuts defining one side wall of the respective grooves are first formed in one blank, that blank then placed alongside a second blank in which a series of initial saw cuts defining the opposite side wall of the respective grooves are to be out, such cuts then made in both blanks simultaneously, the second blank then placed alongside a third blank in which a series of initial saw cuts defining the opposite side wall of the respective grooves are to be out, such cuts then made in both blanks simultaneously, this sequence being repeated for as many blanks as are to be produced.

15. The method according to claim 4, characterized in that the grinding of the grooves in the case-hardened blank is effected, one groove at a time, by a single grinding tool to which the blank is relatively adjusted between two fixed stops.

16. The method according to claim 4, as practiced for the production of a mold cap whose fcre-and-aft grooves taper from the front or linecontacting face of the cap toward the rear or pot-mouth-contacting face thereof, characterized in that the two saw cuts, which define the walls of each individual groove, are made in the soft or unhardened steel blank at angles in exact accord with the required taper of said groove in its final ground condition, and in that the grinding of the grooves in the case-hardened steel blank is effected, one groove at a time, first on one side wall and then on the other, by presenting the blank to a grinding tool alternately at different fixed angles to accord with the required lengthwise taper of the finished grooves.

17. The method according to claim 4, as practiced for the production of a mold cap whose fore-and-aft grooves taper from the front or line-contacting face of the cap toward the rear or pot-mouth-contacting face thereof and also taper from the bottom or casting face of the cap toward the top face thereof, characterized in that the two saw cuts, which define the walls of each individual groove, are made in the soft or un- Lil accord with the required compound taper of said groove in its final ground condition, and in that the grinding of the grooves in the case-hardened steel blank is effected, one groove at a time, first on one side wall and then on the other, by employing a grinding disk having its side faces tapered in accord with the required widthwise taper of the finished grooves and by presenting the blank to said grinding disk alternately at differlO ent fixed angles as measured from a plane coincident with the peripheral center line of the disk to accord with the required lengthwise taper of the finished grooves.

18. The method according to claim 4, as prac- 15 ticed for the production of a mold cap whose fore-and-aft grooves taper from the front or line-contacting face of the cap toward the rear or pot-'nouth-contacting face thereof, characterized in that the two saw cuts, which define the walls of each individual groove, are made in the soft or unhardened steel blank at angles in exact accord with the required taper of said groove in its final ground condition, and in that the grinding of the grooves in the case-hardened steel blank is effected, one groove at a time, first on one side wall and then on the other, by presenting the blank to a grinding tool alternately at different fixed angles to accord with the required lengthwise taper of the finished grooves, and

0 characterized further in that the proper location of the blank to the grinding disk is determined by the tapered form of the respective grooves.

19. The method according to claim 4, as practiced for the production of a mold cap whose fore- 5 and-aft grooves taper from the front or line-contacting face of the cap toward the rear or potmouth-contacting face thereof and also taper from the bottom or casting face of the cap toward the top face thereof, characterized in that 4.0 the two saw cuts, which define the walls of each individual groove, are made in the soft or unhardened steel blank at compound angles in exact accord with the required compound taper of said groove in its final ground condition, and in that the grinding of the grooves in the case-hardened steel blank is effected, one groove at a time, first on one side wall and then on the other, by employing a grinding disk having its side faces tapered in accord with the required widthwise 0 taper of the finished grooves and by presenting the blank to said grinding disk alternately at different fixed angles as measured from a plane coincident with the peripheral center line of the disk to accord with the required lengthwise taper of the finished grooves, and characterized further in that the proper location of the blank to the grinding disk is determined by a conical feeler which is caused to engage the compound tapered side walls of the respective grooves.

20. A case-hardened steel typographical slug casting mold cap with fore-and-aft tapered grooves in its bottom or casting face, the side walls of the respective grooves being case-hardened to a uniform extent.

G5 21. A ground case-hardened steel typographical slug casting mold cap with fore-and-aft tapered grooves in its bottom or casting face, the side walls of the respective grooves being case-hardened and ground down to a uniform extent.

0 22. In or for the manufacture of a ground casehardened steel typographical slug casting mold cap with fore-and-aft grooves in its bottom or casting face, said grooves tapering uniformly from the front or line-contacting face of the cap hardened steel blank at compound angles in exact toward the rear or pot-mouth-contacting face thereof, a soft or unhardened steel blank formed with grooves tapered in conformity with the taper desired in the finished mold cap and Whose side walls are straight throughout their length to permit uniformity in the subsequent case-hardening and grinding operations.

23. In or for the manufacture of a ground case-hardened steel typographical slug casting mold cap with fore-and-aft grooves in its bottom or casting face, said grooves tapering uniformly from the front or line-contacting face 10 and grinding operations.

GEORGE W. ALLISON.