US2688194A - Apparatus for indexing mats used in the color printing art - Google Patents

Description

Sept 7, 1954 c. A. JORDAN 2,688,194

APPARATUS FOR INDEXING MATS USED IN THE COLOR PRINTING ART Filed Aug. l5, 1952 8 SheeizS-Shee(l l j/jgg, 3.

INVENTOR r BVM d' 90m Sept. 7, 1954 c. A. JORDAN 2,688,194

APPARATUS RoR TNDEXING MATS USED 1N THE coLoR PRINTING ART Filed Aug. 13, 1952 8 sheets-sheet 2 IN V EN TOR.

@A A @im 8 Sheets-Sheet f5 C. A. JORDAN INVENTOR. BY a,

@We d ornys.

Sept. 7, 1954 APPARATUS FOR TNDEXING MATS USED 1N THE c'oLoR PRINTING ART Filed Aug. 15, 1952 Sept. 7, 1954 c. A. JORDAN 2,688,194

APPARATUS P0P INDEXING MATS USED 1N THE coLoR PRINTING APT Filed Aug. 13, 1952 8 Sheets-Sheet 4 1N V EN TOR.

C. A. JORDAN Sept. 7, 1954 APPARATUS FOR INDEXING MATS USED IN THE COLOR PRINTING ART \8, Sheets-Sheet 5 Filed Aug. 13, 1952 NVENTOR.

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Sept. 7, 1954 c. A. JORDAN 2,688,194

APPARATUS FOR INDEXING MATS USED IN THE COLOR PRINTING ART Filed Aug. 13, 1952 8 Sheets-Sheet 6 C. A. JORDAN sept. 7, 1954 APPARATUS FOR INDEXING MATS USED IN THE COLOR PRINTING ART 8 Sheets-Sheet 7 F'iled Aug, 15, 1952 INVENTOR.

Sept- 7, 1954 c. A. JORDAN 2,688,194

APPARATUS FOR INDEXING MATS USED IN THE COLOR PRINTING ART Filed Aug, 13, 1952 n 8 Sheets-Sheet 8 1N VEN TOR.

V 1. BY

Patented Sept. 7, 1954 UNITED STATES PATENT maar.

OFFlQE.

APPARATUS FOR INDEXING MATS USED IN THE COLOR PRINTING ART Charles A. Jordan, Buffalo, N. Y., assignor to Buffalo Colorpress, Inc., Buffalo, N. Y., a corporation of New York 8 Claims.

This invention relates to the art of color printing and more particularly to a machine for indexing the mats used for forming the various printing plates so that when these plates print in their respective colors the iinal printed sheet has the colored areas in proper registry.

In color printing, the sheet of paper is successively brought in printing contact With a plurality of printing plates each of which applies one color. In the color printing art, it is common practise to employ four separate plates one for each of the colors yellow, blue, red and black. It is readily apparent that these plates must be formed so that when set up in a conventional printing press the respective colored areas printed by these plates register as intended.

By way of background, the artist designs the subject matter and coloring therefor to be printed. Then a mat is produced for each color to be printed, such as yellow, blue, red and black previously mentioned. With such a color combination, four mats are necessary for each subject matter to be color printed Whether it is of a size to cover a full page or only a portion thereof. These mats are used as forms to cast printing plates. The printer usually receives the set of mats from a supplier and casts his own plates from these mats. Heretofore considerable time has been consumed and diiculty experienced in positioning the mats individually in a casting box so that when the printing plates are cast, finished and mounted on the roll of a conventional printing press, the indicia on the various plates are registered or relatively physically oriented such that the colored areas printed are in proper registry and do not overlap. This has increased the make ready time and hence the expense of the printing job.

The principal object of the present invention is to provide a machine which indexes the mats in a given set of the same so that each mat can be placed in the proper position in the casting box Without relying on the skill of a workman to properly position the mat preparatory to casting.

Another important object is to provide such a machine which indexes each of the mats in a set in a rapid and facile manner so that make ready time is greatly reduced resulting in savings in time and labor costs.

Another object is to provide such a machine which is simple in construction, easy and rapid to operate, relatively inexpensive, sturdy and not likely to get out of order or require repairs.

Other objects and advantages of the invention Will be apparent from the following description and accompanying drawings in which:

Fig. l is a top plan View of a mat prepared for indexing by a machine embodying my invention.

Figs. 2 and 3 are enlarged fragmentary sectional vievvs thereof taken on the correspondingly numbered lines of Fig. 1.

Fig. 4 is an elevational View of the front of a machine embodying my invention, with some parts shown in section.

Fig. 5Vis a top plan View thereof with portions broken away to reveal parts of the machine.

Fig. 6 is an enlarged fragmentary vertical sectional view thereof taken generally on line 6-6, Fig. 5.

Fig. 7 is a fragmentary vertical sectional View thereof taken on line 1 1, Fig. 6.

Fig. 8 is an enlarged fragmentary Vertical sectional view thereof taken generally on line t-t, Fig. 5.

Fig. 9 is a fragmentary vertical sectional view thereof taken on line 9 9, Fig. 8.

Fig. 10 is an enlarged fragmentary vertical sectional View through the pointer head assembly shown at the left of Fig. 9.

Fig. 11 is a vertical transverse sectional view thereof taken on line II-l i, Fig. 10.

Fig. 12 is an enlarged fragmentary vertical sectional View of the clutch assembly shown in Fig. 4 and taken generally on line l2-l2 thereof.

Fig. 13 is a transverse vertical sectional View thereof taken on line 13-13, Fig. 1,2.

Fig. 14 is a perspective diagrammatic view of the mat shown in Fig. 1 and representing a typical positional relation of the primary and secondary pointers of my novel machine to this mat and also showing the mat provided with the indexing markings applied by the machine.

Fig. l5 is a perspective View of a mechanical shear, partly in section and schematic, and showing on its table a mat with indexing markings provided by my novel machine, positioned to be trimmed along a longitudinal side.

Fig. 16 is a view similar to Fig. 15 but showing the mat in position to be trimmed along a transverse end.

Fig. 17 is a fragmentary sectional view of the mechanism for selectively lifting and lowering the index pins shown in Figs. 15 and 16, this view being taken generally on line l'i-il of Fig. 16.

Fig. 18 is a top plan View of a casting box in open position and showing a mat, provided 'with index markings provided by my novel machine and trimmed, arranged in the box.

Fig. 19 is an enlarged fragmentary transverse 3 Sectional View thereof taken on line Fig. 18.

Figs. and 2l are respectively enlarged fragmentary transverse and longitudinal sectional views thereof taken on the correspondingly numbered lines of Fig. 18.

The underlying principle of my machine for indexing each mat of a series of the same required for color printing of a given subject matter, is to determine the imaginary centerlines of the effective printing area of each mat as a Whole in two directions perpendicular to each other so that the location of the imaginary center of such area is determined, and to provide each such mat with indexing markings related in the the same manner to such imaginary center and centerlines. The indexing markings of each mat in a color series can then be utilized to arrange the mats individually and successively in proper position in a conventional casting box modified only slightly to provide mechanical elements for cooperating with the indexing markings whereby proper registry of the printing plates is assured.

As is well known, a mat used in color printing is a pressed fiber sheet formed with raised and recessed areas in accordance with the design and coloring of the subject matter to be printed on the finished paper sheet. A separate mat is provided for casting a printing plate for each color to be applied. Each mat is intended to be placed against the semi-circular face of a casting box and molten metal, usually a lead nickel alloy, allowed to ow over the exposed portion of the mat so as to reproduce the indicia of the mat in the printing or external face of the semi-circular printing plate so cast. The mats in a given set are suitably individually produced so that if the printing plates made therefrom are properly oriented on the rolls of a conventional printing press, the various colors will be in their intended registry. The present invention is not concerned with the production of such sets of mats which is well known to those skilled in the art, but rather with the indexing of the mats in a given set so that the printing plates formed therefrom will be in registry.

A typical mat as received from a supplier is illustrated in Fig. l and is represented by M. This mat may be considered as any one of the set necessary for the various colors to be printed. As shown this mat has an effective printing area A dened by the spaced horizontally exten-ding raised ribs 25, and the spaced vertically extending raised ribs 21, 28, which ribs are integrally joined at their meeting ends and circumscribe the rectangular area A. In an actual mat, this printing area A would include indicia which has been omitted from the illustration in Fig. l since this varies with the subj ect matter to be printed, although raised indicia are suggested at 29. As shown in Figs. 2 and 3, the raised ribs 26 and 21 are lands formed from the body of the sheet material used to produce the mat. The mat is usually provided with liberal perimetral margins, shown in Figs, 1 3 as including inner and outer margins 3U, 3| respectively. These margins are shown as offset one from the other but still below the level of the upper surfaces of the raised ribs 25-28. Generally the mat is trimmed along the boundary line between the inner and outer margins 30, 3| 4so that the mat will t into a semi-circular casting box.

Preparing mat for indering (Figs. 1-3) In preparing the mat for indexing on the machine embodying my invention, the rectangular effective printing area A is bisected along each of three sides. For example, referring to Fig. 1, the horizontal distance between the two points P1 and P2, which lie respectively along the inner edges of the vertical raised ribs 21, 28 and equally spaced from the inner edge of the lower horizontal raised rib 26 so that the measurement is parallel to the same, is divided in half to locate the center point P3. A small mark or indentation is made on the ma-t at this center point P3. In a similar manner the center point P4 is determined in a direction along the left vertical raised rib 21 between the end points P5 and Ps; and the center point P7 between the end points P8 and P9 along the right vertical raised rib 28. The center points P3, P4, P'z may be located in any suitable manner as by measuring with a scale the distance between the respective end points and halving such distance, or by using a bisecting pair of dividers, or even such center points may be on the mats as originally received from the supplier of the same. It will be seen that an imaginary horizontal centerline Ln connecting the center points P4, P7, when perpendicularly intersected by an imaginary vertical centerline Lv extending through the center point P3, would locate an imaginary center C for the rectangular area A.

Each mat in a given color set will have formed therein the raised border ribs 25-28 of the same length and spaced between opposing pairs of the same as is shown in Fig. 1. In other words, the effective .printing area of each mat is the same. Therefore with the practise of my invention it is essential to locate the imaginary center C of each mat of a set and to index each mat with respect to such imaginary center and the imaginary centerlines L11, Lv passing therethrough.

Indexing machine (Figs. 4-13) The machine for so indexing the mats and forming the subject of the present invention is shown in Figs. 4-13. Referring to Fig. 4, the machine is shown as having a cabinet-like frame including vertical left and right side panels 35 and 36 respectively, a rear panel 31, and a front panel 38. These panels support a fiat horizontal plate 39 of generally rectangular outline, as shown in Fig. 5, which provides a table on which a mat can be placed for indexing the same. The mat isheld flat and immovable to this surface by suction. For this purpose, the table plate 39 has a multiplicity of holes 40 arranged over substantially its full area (Fig. 5) to form a working area, and these holes communicate with a suction chamber 4| extending along the bottom of the table plate. The bottom of this suction chamber 4| is enclosed by a horizontal plate 42 which is joined along its perimeter to the various panels of the machine frame. Suction is applied to the chamber 4| through a pipe 43 connected at one end to the plate 42 and at its other end to a vacuum pump 44 of any suitable type. This pump is shown as mounted on a shelf 45 of the machine frame which shelf also supports an electric motor 46. This motor drives the vacuum pump 44 through a belt 48. A master switch (not shown) for turning the motor 46 on and off is preferably provided.

Suction can be selectively applied to the suction chamber 4| and to this end the pipe 4Sy is provided with a suitable valve 49 (Fig. 4) operated under control of the lever 50 (Fig. 5) shown as extending outwardly slightly from the front side of the machine. When the valve 49 is closed the pump 44 is connected with the suction chamber 4I, but when opened by manipulating the lever 5l!` the pump is bypassed to the atmosphere and thereby disconnected from this chamber.

Power actuated means are provided for making indexing markings on a mat arranged in suitable position on the table plate 39. Such means are shown as including two punches 52 and 53 (Fig. li) and a marker 54 (Fig. 6). All three marking devices are disposed above the table plate and operatively arranged for being moved vertically downwardly toward this plate. so as to apply indexing markings to a mat arf ranged thereon. The punches 5 2, 53 are shown as arranged in line with each o ther along the transverse centerline X--V-X of the table plate 39 (Fig. 5) and adjacent opposite ends thereof with the punch 52 at the left and the punch 53 at the right as shown in Figs. i and 5. The marker 54 is shown as arranged adjacent the rear of the machine and inline with the centerline of the table plate 39 running from front to rear of the machine. The machine centerlines X-X, Y-Y are perpendicular to each other and intersect at point D (Fig. 5) with the centerline Y-.Y bisecting the distance between the opposing side surfaces of the punches 52, 53. Point D is there? fore the center of the working area of the table plate 39 and the imaginary center of a mat, such as the center C of the mat M shown in Fig. 1 must be registered with the center D of the table plate working area, as well as the mat centerf lines Lh and Lv being alined with the machine centerlinres X-X, Y-Y respectively, before the mat is indexed by the punches 52, 53 and marker 5d, as later described herein. 'V

'The punches 52 and 53 are a fixed distance apart whereas the marker 54 can be adjusted along the machine centerline Y-Y 4toward or away from the transverse Vmachine centerline X-X on which the punches are located. The operative lower end of punch 53l is circular in cross section so as to punch a round hole whereas the operative lower end of punch 52 is elongated with rounded ends so as to punch a slot-type hole.` Except for these differences, the punches'52,v 53 and their supports and operating mechanisms are identical. Hence only a detailed description of one will be made.

Each of the punches 52, 53 is slidingly mounted for vertical movement on a horizontal arm 56 extending inwardly from a bracket 51 suitably mounted on the table plate 39 adjacent the late eral end thereof. A pair of spacedcears 58fcxtend upwardly from the arm 56` on opposite'sides of the punch 52 or 53 and 'serve as journals for a horizontal shaft 55. An eccentric 4carri 64,0 fast' to this shaft and arranged between the ears 58 and works on a seat 6| provided on the upper end of the punch (Fig. 8); Each punch is shown as biased upwardly by a helical compression spring 62 interposed between the corresponding arm 56 and a lateral extension 63 on this punch,` as shown for the punch 53 in Fig. 8.

Each cam shaft 55 is shown as driven by similar means which include a bevel gear 54 fast to this shaft adjacent its outer end, in turn driven by a bevel gear 55 fast to the upper end of a vertical jack shaft 55 which has another bevel gear 51 fast to its lower end, a bevel gear 58` mating therewith mounted on the end of a horizontal cross shaft 55. The corresponding pairs of gears4 64, 5.5 and 6l, 53 are arranged in housings 'HlA and 'H respectively which also serve as jour.- nals for the corresponding ends of the shafts onk 6. which these gears are mounted. The housing. 'la is shown as mounted on the upper end of a ver: tical bar 1.2 extending upwardly from the machine frame along the side thereof, and the housing 'tl as mounted on the side panel of the machine. A horizontal bar 13 connects the two gear, housings. l() on opposite sides of the machine.

Returning to the, mechanical drive, the horizontal cross shaft 59 is shown as having a bevel gear 'M connected thereto intermediate its ends and additionally journalled on one flange of. an angle bracket i5 cleperldtney from the. lowery herir, zontal plate ft2 (Figs. 4 and 12). The gear 'i4 meshes with another bevel gear 'l5 fast to the front end of a horizontal clutch shaft 'le which extends in a direction fore-andfaft of thev machine. The front end of this clutch shait la is, j durnaled on the` other flange of the angle bracket l5 and its rear end is suitably journaled on the rear panel 5l, of the` machine frame, as sllOWn in Fig. l2. The clutch shaft carries a one-revolution clutch indicated at 'l5 which may be of any suitable construction. This clutch is actuated by a lever Bil pivotally mounted on the bracket at 8| and this lever is shown as manip;-l ulated by a hand lever 82 arranged on the front of the machine frame (Fig. 5). The clutchv i5, is driven by a pulley 85 which in turn is driven by another but smaller pulley 54 through a belt 85 which passes around these pulleys. The pulley 84 isv fastV to a countershaft 85 suitably journaled on the machine frame and. to which a larger pul-` ley. Si@ is also fast. A belt- 35 from the motor i5 drives the pulley 824i,

The marker 55 is slidingly mounted for ver-y tical movementon a slide e2 which is movable along a horizontal bar 53 as shown in Figs. 6 and 7. AThis 'bar'SS extends in a fore-'and-'aft direction of the machine parallel to and. above the fore-andaft centerline Y-Y of the table plate.

working area. At its rear end the bar 55 rigidly connected to an upright ed extending upwardly from the. rear side of the machine frame` and at its front end this bar `is shown as rigidly connected to a block et which in turn is rigidly connected to a horizontal bar 9,5. This barv 9 5 is spaced'above the table plate'tii and extendsl` across the full width thereof, being rigidly conf-A nected at its opposite ends to the vertical bars 'l2'. This transverse bar 95 is parallel to the transverse centerline X--X of the table plate working area.

Referring to Fig. '7, the slide 5?. is shown as embracingthe bar 93 which is out of round in cross section` to prevent relative turning between thel slide 'and' bar. Friction between the engaging surfaces of. the slide 92 and bar holds the; formerl in any. adjusted position along the latter although suitable locking means may be employed if desired. The marker 55 is shown as having its lower end tapered to provide a line edge 95 adapted to engage the upper surface of a mat ano. place a center mark on the same for a pur. Dese hereinafter described. The line edge tais` in vertical alinement with the fore-andgaft centcrline` Yf-YY of the machine. The marker 5eK isv constantly urged toward an elevated position by a helical compression spring 5 9 arranged be@K tween the top of the slide 5,5 and a lateral ex;y tension, mil on the marker. The upper extremity of the marker is formed with a seat lei which engages with an elongated eccentric earn, M121. The stub ends i123, 54, of this cam 152 aresuitf` ablyl journaled in the block 95 and upright 9a respectively as shown in Fig. 6. The rear stub. end 104 extendsV through the upright 9,5 and. its.

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7., extremity has fast thereto a bevel gear |05 which meshes with another bevel gear |06 fast to the upper end of a vertical jack shaft |08 extending along the rear of the machine frame. This vertical shaft |08 is suitably journaledat its upper end in a housing |09, which also houses the bevel gears |05, |06 (Fig. 6), and at its lower end is suitably journaled in a housing ||0. The lower extremity f the vertical shaft |08 has a bevel gear fast thereto and this gear meshes with another bevel gear ||2 fast to the rear end of the clutch shaft 13. The housing |0 also houses the bevel gears ||2.

It will therefore be seen that when the manual control lever 82 for the one revolution clutch 19 is swung so as to lift the clutch lever 80 the clutch is permitted to drive the clutch shaft 18 for one revolution, the control lever 82 being manually released in time to disengage the clutch after one revolution of the shaft. Turning of the clutch shaft 18 through the various gearing previously described also rotates the shafts 69, 66, 59, |08 thereby to rotate the eccentric cams 60 for the punches 52, 53 and the eccentric cam |02 for the marker 54. It is to be noted that when the cams 60 and |02 are at rest their salient part projects vertically upwardly so that the punches and marker are in their extreme elevated position. It is further to be noted that the marker 54 works in opposition to the table plate 39 whereas this plate has an insert ||3 provided with a hole ||4, as shown in Fig. 8, to receive the end of the corresponding punch. A discharge chute l is shown in Fig. 8 as arranged under the hole |4 to receive the slugs or cut outs stamped from the mat which is placed on the table plate 39. Such an insert and discharge chute are provided for each of the punches 52, 53.

So far, the indexing marking means have been described. The means for positioning or orienting the mat on the table plate 39, preparatory to marking, will now be described. As previously described, considering the mat M shown in Fig. 1, the imaginary centerline Ln of the mat must be alined and superposed with the transverse centerline X-X of the table plate working area connecting the centers of the punches 52, 53. As well, the imaginary centerline Lv of the mat M must be alined and superposed with the fore-andaft centerline Y--Y of the table plate working area along which the marking edge 98 is rectilinearly movable. When this alinement of the mat and machine centerlines is effected the imaginary center C of the mat will register with the center D of the table plate working area. It is only after a mat has been so oriented or positioned that the punches 52, 53 and marker 54 are actuated.

For so positioning the mat, three primary pointers |20, |2 |22 are provided and are adapted to be registered with the center points P4, P7, P3 respectively of the mat M shown in Fig. l. The pointers |20, |2| are arranged for horizontal movement along the transverse centerline X-X of the machine with the pointer |20 being adjacent the punch 52 and the pointer |2| being adjacent the punch 53. The pointer |22 is also arranged for horizontal movement but along the fore-and-aft centerline Y-Y of the machine.

Each of the pointers |20, |2| is shown as carried on a slide |23 which is Sldingly arranged in a slideway |24 provided on the front face of the transverse bar 96 as best shown in Figs, 4 and 6. The slides |23 and slideway |24 preferably have a dove tail connection as shown.

Referring to Fig. 6, `the pointer |22 is shown as carried on the front end of a horizontal rod |25 which extends in a fore-and-aft direction of the machine parallel to the centerline Y-Y. This rod |25 is slidingly arranged on the block 55 and upright 94 each of which carry a key |26. The keys |26 project into an elongated keyway |21 provided longitudinally in the rod |25 so as to prevent this rod from turning but yet permitting it to be moved in a longitudinal direction.

The pointers |20, |2|, |22 are each mounted for vertical movement relative to their respective supports. Normally these pointers are held in an elevated position above the table plate but they can be individually and selectively released to a lowered position in which they are biased downwardly toward the table plate 39. Similar means are provided for each pointer for this purpose and the details of the same will be described only in connection with the pointer |22. Referring to Fig. 6, the pointer |22 is shown as embedded centrally in the lower end of a plunger |29 which is slidingly arranged in a vertical tube |30. The upper end of this tube is closed by a removable plug |3| and a helical compression spring |32 is arranged within the tube between the opposing ends of the plug |3| and plunger |29. This plunger carries a laterally extending pin or handle |33 which projects through a bayonet -type slot |34 provided in the tube |30 and having connected horizontal and vertical branches. It will be seen that with the pin |33 disposed in the vertical branch of the slot |34, the spring |32 expands to force the plunger |29 downwardly and thereby moves the pointer |22 toward the table plate 39 as shown in Fig. 6. When it is desired to raise the pointer, the pin |33 is lifted and turned laterally into the horizontal branch of the slot |34 which locks the pointer in an elevated position. The tube |30 is shown as mounted to a bracket |35, in turn secured to a block |36 by screws |31. The block is suitably rigidly connected to the front end of the rod |25.

The means for vertically moving the pointers |20, |2| are similar to those described for the pointer 22 and hence the same reference/numerals have been applied, although it is to be noted that the tubes |30 and the plungers internally arranged therein for the pointers |20,

|2| are shorter so that the upper ends of these tubes do not interfere with the rod |25 or arms 56, as shown in Fig. 6.

The machine is also shown as provided with a set of three secondary pointers |33, |40, |4| (Figs. 4, 5). Each of these secondary pointers is adjustably mounted for movement to various selected locations over the working area of the table plate 39 and for a purpose hereinafter described.

The adjustable support means for each of the secondary pointers |39, |40 are identical and hence only that for the pointer |40 shown in Fig. 8 will be described. Each of the horizontal arms 56 overhanging the table plate is provided with a horizontal guideway |42 on its front face (Fig. 4). A slide 43 is slidingly arranged in each such guideway |42 and these parts preferably have a dovetail connection. Each slide |43 may be maintained in any adjusted position along its guideway by tightening a set screw |44. That end of each slide |43 toward the centery of the machine is shown as formed to provide an enlarged head |45 which projects laterally from the slide toward the front of the machine (Fig. 8).

This head |45 has a square hole |46 extending vertically through it to guidingly receive a screw |47 having four flat sides which are slidable along the walls of the square hole |46. The head |45 is slotted between the ends of its vertical hole |66 as indicated at les in Fig. 8 to provide opposing at vertically spaced horizontal walls. A i-lat nut It@ is arranged in the slot |48 and threadedly connected to the screw |47, the vertical thickness of the nut being such as to closely nt the walls of the slot. The nut |49 is disk-like and of a large enough diameter so that its periphery which is preferably knurled projects laterally outwardly beyond the sides or" the head |45. Thus by turning the nut Mtl the screw |47 which cannot turn may be adjusted up or down as desired.

The lower end of the vertical screw M7 is suitably rigidly connected to the rear end of a forwardly projecting horizontal arm lil. rihis arm |59 is preferably uniformly square in cross section along its full length as shown in Fig. 9 to serve as a bar on which a slide i! is slidably mounted and held in any desired adjusted position therealong by a set screw |52. The slide |5| which is in the form of a block having a square hole through which the arm |55 extends, has a depending lower portion provided with a horizontal transverse hole |52 extending therethrough. A screw |511 similar to the screw lill is slidably arranged in the hole. A nut |55 similar to the nut Ulti is arranged on the screw |5d and partially within a slot provided in the slide |5|. Thus by turning the nut |55 the screw can be moved perpendicularly to the arm Illia.

Referring to Figs. 9-l1, one end oi each screw |515 is shown as reduced and externally threaded as indicated at |56 to receive an internally threaded collar |57 which is in the form of a disk and screwed up tight against the shoulder formed on the end of the screw |54. A flat plate |58 ts against the outer face of the collar |57 and is held thereagainst by a screw |59 passing through a hole in the plate and having its inner end threadedly received in the screw |54. A recess |6i in the plate |58 and opening to that face thereof which engages the collar |56, houses a wind up spring This spring surrounds the screw |53 and has one end suitably anchored to the plate |58 and the opposite end suitably i anchored to the collar |57 as shown in Fig. l0. The spring i6! operates to urge the plate |58 to turn in a counterclockwise direction relative to the collar |56 as viewed in Fig. 1l and about the axis oi the screw |55. of the plate Uit is provided with a square hole extending transversely of the axis of the screw |5S| and an arm |66, also square in cross section, is slidably arranged in this hole. The arm |63 extends in a direction parallel to the horizontal arm |5|l and can be held in any desired adjusted longitudinal position relative to the plate |552 by the set screw itil. The rear end of the arm |63 is shown in 8 as holding the pointer Uli! which depends therefrom.

Even though the spring i6! is arranged to urge the pointer his downwardly toward the table plate 39, it is desired that the pointer |46 be normally held in an elevated position as represented by broken lines in Fig. 8. This is eccomplished by providing detent means between the plate its and collar |57. Referring to Figs. l0 and 1i, such means includes a spring loaded ball |65 carried by the inner face of the plate |518 and adapted to be received in a semi-spherical The lower portion recess |66 provided in the opposing race of collar |57. Thus when the ball |65 is opposite the recess |66 and projects into the same, the arm its is held in the elevated position shown by broken lines in Fig. 8 but by merely depressing this arm to the full line position shown the ball |65 against the urging of its spring is forced to leave the recess |66 and rides on the nat face of the collar |57 while the wind up spring itil expands to urge the pointer |40 downwardly. In this latter condition of the parts, the position of the detent ball i5 represented by broken lines at |55 in Fig. ll.

The third secondary pointer ifll projects downwardly from the rear end of an arin |68 which is similar to the arms |63 for the other secondary pointers |39, MG. Referring to Fig. 6, this arm |66 is adjustably mounted on a holder similar to the plate |55 shown in Figs. 9 and 10 and this holder has the saine detent means shown in Figs. 9-11 for normally SulODOrting the arm in an elevated inoperative position but permitting the arm to be'released and urged downwardly toward the table plate. Hence this construction has not been reillustrated in connection with the arm |63 and the same reference characters have been employed to indicate like parts. The only difierence is that the disk-like collar |57 in Fig. 6 is shown as being suitably connected to one end of a block it which adjacent its opposite end is provided with a vertical square hole which slidingly receives a vertical bar 76, square in cross section. The connection between the block |66 and vertical bar il@ is maintained in any relative adjustment of these parts by a set screw |7| as shown in Fig. 4.

The upper portion of the vertical bar lill extends through a square hole provided in a head |72 and held in any adjusted position relative thereto by a set screw |73. The head lli is also formed to provide a horizontal square hole to one side or its vertical square hole and this horizontal hole slidingly receives a horizontal bar VM, square in cross section. The head |72 is maintained in'its desired adjusted position on the bar |711 by a set screw |75. This horizontal bar |74 projects forwardly from the transverse horizontal frame bar 73 and is adjustably mounted on the latter for movement longitudinally thereof. For this purpose the rear end of the movable horizontal bar |'ll is suitably rigidly connected to a slide il which embraces the transverse horizontal frame bar 73 and is slidable therealong and can be held in any desired position longitudinally thereon by a set screw |77.

Fine adjustments of the slide |75 can be obtained by the following means. Adjacent to and independent of the slide |76 is an auxiliary slide |86, also embracing the transverse horizontal frame bar 73, as shown in Figs. i and .5. This auxiliary slide is movable along the bar 73 but can be made fast thereto by a set screw lill. A horizontal screw |32 fast at one end to the slide |76 projects through a hole provided in the auxiliary slide |86 and a nut |33 works on. this screw. The nut m3 is arranged in a recess provided within and opening to one side of the auxiliary slide |66 and is constrained by the opposing walls thereof against movement relative thereto along the axis of the screw |32. The periphery of the nut |33 projects outwardly from the body of the auxiliary slide and is preferably lrnurled :for easy manipulation. Thus with the set screw lill tightened to hold the auxiliary slider immovable and the set screw |11 loosened to render the main slide |13 movable, the nut |83 may be turned so as to adjust the relative spacing between these two slides and therefore permit of fine adjustment of the main slide |16 longitudinally of the horizontal frame bar '|3. Of course, with both set screws Hl' and |8| loosened the two slides |16 and |62 can be shifted along the bar 13 as a unitary structure.

Operation of indeing machine Preparatory to operation of the indexing machine, the primary pointers |20, |2|, |22 are checked to be sure each is locked in its elevated position. This is done by placing the pin |33 associated with each primary pointer |20, I2|, |22 in the horizontal branch of the bayonet type slot |34 in the respective tube |30 (Fig. 6) Likewise, the arms holding the secondary pointers |39, |40, 14| are examined to be certain each is in its elevated position, normally held there by its respective detent means |65, |66 shown in Figs. and 1l. With all primary and secondary pointers raised there is clearance to slide a mat on the table plate 39.

Thereafter the electric motor 46 is turned on and the control lever 50 for the vacuum by pass valve le is positioned so that suction is not established in the suction chamber 4|. Also the control lever 82 is in a position to render the one revolution clutch 19 inoperative.

The mat M shown in Fig. 1 is then placed face up with the center points P3, P4 and P1 exposed on the table plate 39 of the machine by sliding it under the raised pointers. The mat M is then shifted on the table plate to register the center points P1, P1 and P3 with the primary pointers |20, l2l, |22 respectively. In doing this one of the primary pointers, say the primary pointer 22, is rst lowered to engage the center point Ps. Then the mat is swung about this point contact to register the primary pointers |20, |2| with the center points P4, P1 respectively, and these pointers are lowered in turn to engage their respective center points on the mat. 'Ihe lowered positions of the primary pointers are diagrammatically illustrated in Fig. 14. In registering the primary pointers |20, |2|, |22 with the respective center points P4, P7, P3, the mountings for these pointers are adjusted or shifted along their respective supports to permit the necessary three point contact with the mat center points. Thus the rod supporting the primary pointer 22 can be shifted as desired along the fore-andaft axis Y-Y of the machine, and the slides |23 carrying the primary pointers |20, |2| can be shifted individually along the slideway |24 on the transverse bar 96 and hence along the transverse axis X-X of the machine, as shown in Fig. 6. This adjustment of the movable supports for the primary pointers |20, 2|, |22 and the mat M in order to bring these pointers into registry with the respective center points P4, P'1, P3 on the mat, takes only a few seconds. The primary pointers are individually lowered by swinging the respective pin |33 to aline the same with the vertical branch of the bayonet type slot |34 and these pointers are urged into firm contact with the mat by their respective springs |32, as shown in Fig. 6.

With all three primary pointers lowered in any order desired and engaging their respective center points on the mat it is evident that the mat has been oriented such that its imaginary centerline Lh is alined with the transverse center- 12 line X--X of the table surface 39 and the imaginary centerline Lv of the mat is alined with the fore-and-aft centerline Y-Y of the table surface so that the mat center C is superposed with the center D of the table working area.

After the mat M has been so centered, suction is applied to the holes 40 in the table plate 39 so as to firmly hold the mat in this centered position. This is accomplished by manipulating the control lever 50 so as to connect the suction pump 44 With the suction chamber 4|. Utilization of suction to hold the mat in position avoids relying solely on the primary pointers for this purpose and accidental or unintentional displacement of the mat from its centered position is also minimized. Suction also maintains the mat flat.

Thereafter each of the secondary pointers |30, |40, |4| is in any order desired adjusted to register with a register or reference mark on the particular mat being processed which mark is common to all the other mats in the set to be indexed. Such register marks are usually a dot or cross formed as an integral part of the mat, either as a depression or a raised element, at different locations over the face of each mat, but all mats in a given set have register marks in corresponding locations. Instead of a predetermined register mark, a reference point for each of the secondary pointers may be selected as a part of the indicia of one mat which is common to the other mats in the set. Typical register marks are shown on the mat M at R1, R2, R3, with R1 being located slightly to the right and below center point P4, with Rz to the left and below center point P1, and with R3 to the right and above center point P3. In Fig. 14, the registry of the secondary pointers |39, |40, |4| with the register marks R1, R2, R3 respectively, is illustrated. It is to be specifically understood that each mat in a given color set has register marks corresponding to R1, R2, R3 for the mat M shown in Figs. 1 and 14. It is also pointed out that the register marks for different sets of color mats may be different but they are the same for a given set.

Each of the secondary pointers |39, 40, 4| is lowered to engage its respective register mark R1, Rz or R3 after the mountings for these pointers have been adjusted or shifted on their respective supports to bring about registry.

Thus in adjusting the positions of the secondary pointers |39, |40 to bring them into registry with the register marks R1, R2 respectively, the companion slide |43 can be moved along its guide- Way |42 after first loosening the set screw |44 to roughly position these pointers transversely of the machine. The set screws 44 are then retightened (Figs. 4 and 8). Final tine horizontal transverse adjustments of the pointers |39, |40 can be made by turning the respective nuts |55 (Figs. 4 and 9). Adjustments of these pointers fore-and-aft of the machine can be effected by loosening the set screw |52 and shifting the companion slide |5| along the arm |50 to the position desired and. thereafter the set screw |52 is retightened (Figs. 5 and 8). Also adjustments in this same direction can be made by loosening the set screw |64 and shifting arm |63 relative to the holder |58 and thereafter retightening this set screw (Figs. 8 and 9). Fine vertical adjustments of the arms |50 are made by turning the nuts |49 (Fig. 8).

The secondary pointer |4| can also be adjusted to a position in registry with the register mark R3 on the mat. For horizontal adjustments of the Same in a direction extending transversely of the machine, the set screws I'I'I and I8| are first loosened and then the connected slides |16, |80 shifted along the upper transverse frame bar 13. For fine adjustments, the set screw ISI on the auxiliary slide Iil is tightened while leaving the set screw lil for the main slide Ii loose, and then turning the nut |63 (Figs. 4 and 5). When the fine adjustment is completed the set screw I'I'I is tightened. For horizontal adjustments of the secondary pointer Ill! in a fore-and-aft direction of the machine, this may be achieved by loosening the set screw |75 to permit the head |12 to be slid along the bar I'M and then retightening this set screw, and also by loosening the set screw its and shifting the arm |63 relative to the holder |53 and then retightening this set screw (Figs. and 8). Vertical adjustment can be made by loosening the set screw |l3 and then moving the vertical bar up or down as desired relative to the head |12, and thereafter f retightening the set screw |13.

The condition has now been reached where all the primary and secondary pointers are in registry with their respective predetermined positioning marks, as shown in Fig. 14. The mat M is then ready for index marking which consists in punching therein the round hole |85, the elongated hole iii, and applying thereto the line mark itl, also as shown in Fig. 14, The punch 53 makes the round hole |85, the punch 52, the elongated hole it, and the marker 54 the line mark Il. These index markings are performed simultaneously by the operator moving the control lever 82 for the clutch 'i9 so as to lift the stop lever iii? and permit the clutch to be operative for one revolution, at the end of which the clutch is again rendered inoperative automatically. Through the mechanism previously described the punches 52, 53 and marker 54 are driven downwardly toward the mat to produce the index marking thereon and automatically return to their elevated positions.

Following this all of the primary pointers |28, |2I, |22 and secondary pointers |39, |40, |4| are individually raised out of contact with the mat M. In the case of the primary pointers this is done by lifting the pins |33 and swinging them into the lateral branches of the slots |34. In the oase of the secondary pointers this is merely done by tipping up the arms |63, Hi8 supporting the same and the detent means previously described will hold these arms in this tipped up position as shown by broken lines in Fig. 8. It is important that the adjustments of the support means for the secondary pointers are not disturbed. The

control lever 5i! for the suction by pass valve 49 is then manipulated so that this valve disconnects the suction pump fifi with the suction chamber thereby destroying the suction hold on the mat M and this mat now indexed is slid out from under tie pointers and isready for the next operation.

Before describing this, the disposition of the remaining mats in the color set to be indexed should be considered. Flach of these remaining mats, which it will be remembered bears register marks R1, R, R3 in the identical relation to the imaginary centerlines of such mats as for the mat are placed one at a time on the table plate 39 of the machine for indexing. Each mat is oriented so that its register marks R1, R2, Re are in registry with the respective secondary pointers |39, Il, MI, and these pointers are lowered in succession as such registry is obtained, The suction control lever 5i) is then moved to apply suction to the mat and thereafter the clutch control lever B2 is moved to actuate the clutch 'i9 for one revolution which actuates the punches 52, 53 and marker 54 to produce the indexing markings |85, |36, |87 on this mat. Following this the secondary pointers |39, Isl?, IM are lifted out of engagement with the mat, the suction control lever is again moved to cut ofi the suction hold on the mat, and the mat is removed.

In this manner each of the mats in turn is indexed quickly. It is to be noted that only the iirst mat M had to be provided with the center points F3, P4, F7 and the primary pointers 26, IBI, 22 were used only on the first mat, being retained in their elevated positions While indexing succeeding mats in the set. In other words, the secondary pointers |39, |43, |4| are used only to, determine the centered positions of the succeeding mats. If desired, each mat in a set could be provided with center points P3, P4, P7 similar to those for the iirst mat M, and the primary pointers operated in connection therewith, but there would then be no need for the secondary points and, more important, considerable additional time would be required. Accordingly, it is preferred to follow the procedure rst described.

As a result of the use of my novel indexing machine it will be seen that each mat in a given color set is provided with a pair of holes |85, |86 a predetermined distance apart, and preferably also a line mark |8l' which if extended would bisect said distance, with these holes and mark on the imaginary centerlines of the effective printing area A. of each mat. The line mark |81 may be in the nature of a score so as to be visible from opposite sides of the mat and also if desired the line edge 93 of the marker 5d may have a colored dye applied thereto, if desired, although means for doing this are not shown in the drawings. The sole advantage of making a colored line mark |87 is to render it more conspicuous.

Trimming of mat (Figs. 15-16) After each mat is indexed as above described, the same is trimmed in order to iit it into the casting box shown in Figs. 18-21. The procedure is the same for each mat and hence will be described only in connection with the iirst mat M.

While the trimming and casting box operations form no part of the present invention, they are described to show the utility of indexing the mats.

The indexing markings |85, |86, I8? of the mat M shown in Fig. le are utilized in trimming this mat. As shown in Figs. 15-1'7, the numeral |90 represents the table of any suitable conventional mechanical shears having two retractable pins ll, lill rising therefrom. Referring to Fig. 17, each pin |9| is urged downwardly by a spring |92 against a flat surface or a rotatable step cam |93. This cam is mounted on a shaft |9l turned by the handle 95. When the handles are in the position shown in Fig. l5, the pins Il rest on the high steps of the cams |93 and project upwardly through the table but when these handles are in the down position shown in Fig. 16, the pins rest on the lower steps of the cams and are flush with the table.

The stationary blade of the shears is the rear edge of the table |88 and cooperates with a movable blade |96. rIhe pins IQI are arranged on aline |91 parallel to and a predetermined distance from the rear edge of the shear table which line continues over end guides |98, |98 having opposing faces perpendicular to this line.

It is only necessary to trim the mat along the longitudinal side adjacent the line center mark |81 and the two shorter transverse ends. To trim the long side the mat M is placed so that the holes |85, |80 t over the upstanding pins ISI. The shear is then closed and cuts the mat along the line ISS which passes through the center mark |81 on the mat, as shown in Fig. l5. Thereafter the pins |i| are retracted and the mat is turned 90 degrees on the table so that the cut edge |90 is placed against one of the end guides |83. The center mark |81 on the mat is alined with a second line 200 on the table which is spaced farther away a predetermined distance from the cutting line of the shears as shown in Fig. 16. Closing the shears trims the mat along a line just outside the hole |85. The mat is then turned 180 degrees and inverted so that the center mark |81 showing through the reverse side of the mat is alined with the line 200 and abuts against the other end guide |98. Closing the shears trims the mat along a line intersecting the elongated hole |38 therein.

Placing mat in casting boa: (Figs. .Z8-21) Figs. 18-21 illustrate a conventional casting box which includes a trough shaped mold 202 having a semi-cylindrical cavity and pivoted by hinges 203 to cooperate with the convex surface of an upright stationary mold (not shown). The mold cavity receives the mat M and to insure the proper positioning of the same therein, I have modified the mold 202 to the extent of providing two indexing pins on opposite sides of the mold and adjacent the longitudinal free edges thereof. One such indexing pin is indicated at 204 and the other at 20d, and these pins are adapted to t the holes |235 and |85 respectively in the mat.

Each of the indexing pins 21M, 205 is retractable and for this purpose is shown as arranged on the inner end of a stem 2% projecting through a hole in the mold 2622 and having a handle 201 on its outer end. The hub of the handle 201 is inclined along its inner face which cooperates with a stationary inclined face so that a camming action is achieved when the handle is turned to shift the stem axially. arranged to urge the indexing pin to a projecting position as shown in Fig. 19.

The indexed and trimmed mat M is arranged on the indexing pins 204, 205 with the trimmed longitudinal edge |09 of the mat adjacent the hinges 203. This edge is covered by the usual curved foot stick 2553 maintained in position on the mold 202 by abutments 20S. The opposite untrimmed edge of the mat is covered by a sheet 2 i ii of suitable material so that when the casting box is closed metal will not ow between the mat and the inner concave .face of the mold 202. The trimmed short ends of the mat are covered by angle rails 2|! hinged to the mold 202 and these rails cover the said ends of the mat as shown in Fig. 20. The rails are shown open in Fig. 18. When the casting box is closed and metal is run into the space between the mat and the stationary mold part (not shown), the metal abuts the axially facing edge of the foot stick 208 and the circumferentially facing edges of the rails 2l to form the printing plate 2|2.

A spring 208 is operatively Following casting, the casting box is opened,

the cast plate 2|2 is removed from the mold 202. The printing plate 2|2 is subsequently trimmed and processed in accordance with conventional procedures but these form no part of the present invention.

From the foregoing it will be seen that the present invention provides a machine for indexing mats used in color printing so that each mat can be placed in a casting box with assurance that the printing plates cast will be in proper registry with one another when mounted on the rolls of the printing press.

I claim:

l. Apparatus for indexing mats used in the color printing art to insure that printing plates made therefrom will be registered, comprising a table surface adapted to receive a mat thereon, a series of at least three pointers mutually spaced apart and arranged above said table surface and selectively lowerable for engaging predetermined center points arranged on the mutually perpendicular centerlines of a mat arranged on said table surface, means urging said pointers toward said table surface, releasable means arranged to hold said pointers in a retracted position away from said table surface against the urging of said last mentioned means, spaced punches arranged in a normally elevated position above said table surface and in a ixed spaced relation to each other, and power actuated means arranged to lower said punches simultaneously to form indexing holes in the mat.

2. Apparatus for indexing mats used in the color printing art to insure that printing plates made therefrom will be registered, comprising a table surface adapted to receive a mat thereon, a series of at least three pointers arranged above said table surface, two of which are arranged for movement along a rectilinear line and the third of which is movable along another rectilinear line which perpendicularly intersects said rst mentioned line, means urging said pointers toward said table surface, releasable means arranged to hold said pointers in a retracted position away from said table surface against the urging of said last mentioned means, said pointers being selectively lowerable for engaging predetermined center points arranged on the mutually perpendicular centerlines of a mat arranged on said table surface, spaced punches arranged in a normally elevated position above said table surface and in a fixed spaced relation to each other, and power actuated means arranged to lower said punches simultaneously to form indexing holes in the mat.

3. Apparatus for indexing mats used in the color printing art to insure that printing plates made therefrom will be registered, comprising a table surface adapted to receive a mat thereon, a series of at least three pointers arranged above said table surface, two of which are arranged for movement along a rectilinear line and the third of which is movable along another rectilinear line which perpendicularly intersects said first mentioned line, means urging said pointers toward said table surface, releasable means arranged to hold said pointers in a retracted position away from said table surface against the urging of said last mentioned means, said pointers being selectively lowerable for engaging predetermined center points arranged on the mutually perpendicular centerlines of a mat arranged on said table surface, a pair of punches arranged a fixed distance apart on said first mentioned line and on opposite sides of said two pointers and normally in an elevated position above said table surface,

and power actuated means arranged to lower said punches simultaneously to form indexing holes in the mat.

lhApparatus for indexing mats used in the color printing art to insure that printing plates made therefrom will be registered, comprising a table surface adapted to receive a mat thereon, a series of at least three primary pointers arranged above Vsaid table surface, two of which are arranged for movement along a rectilinear line and the third of which is arranged for movement along another rectilinear line which perpendicularly intersects said first mentioned line, means urging said primary pointers toward said table surface, releasable means arranged to hold said primary pointers in a retracted position away from said table surface against thel urging of said last mentioned means, said primary pointers being selectively lowerable for engaging predetermined center points arranged on the mutually perpendicular centerlines of a mat arranged on said table surface, a plurality of secondary pointers each arranged over said table surface for selective adjustment in all horizontal directions to different locations, means urging said secondary pointers toward said table surface, releasable means arranged to hold said secondary pointers in a retracted position away from said table surface against the urging of said last mentioned means, said secondary pointers selectively lowerable for engaging predetermined register points on a mat arranged on said table surface, spaced punches arranged in a normally elevated position above said table surface and engageable with the marginal porv tion of a mat after the same has been properly positioned on said table surface, and power actuated means arranged to lower said punches simultaneously to form indexing holes in such mat.

, 5. Apparatus for indexing mats used in the color printing art to insure that printing plates made therefrom will be registered, comprising a table surface adapted to receive a mat thereon, a series of at least three primary pointers arranged above said table surface, two of which are arranged for movement along a rectilinear line and the third of which is arranged for movement along another rectilinear line which perpendicularly intersects said first mentioned line, means urging said primary pointers toward said table surface, releasable means arranged to hold said primary pointers in a retracted position away from said table surface against the urging of said last mentioned means, said primary pointers being selectively lowerable for engaging predetermined center points arranged on the mutually perpendicular centerlines of a mat arranged on said table surface, a plurality of secondary pointers each arranged over said table surface for selective adjustment in all horizontal directions to different locations, means urging said second-- ary pointers toward said table surface, releasable means arranged to hold said secondary pointers in a retracted position away from said table surface against the urging of said last mentioned means, said secondary pointers being selectively lowerable for engaging predetermined register points on a mat arranged on said table surface, a pair of punches arranged a fixed distance apart on said first mentioned line and on opposite sides of said two primary pointers and normally in an elevated position above said table surface and engageable with opposite marginal portions of a mat to punch holes therein when such mat is properly series of pointers arranged above said table surface and selectively movable theretoward for engaging predetermined positioning marks on a mat arranged on said table surface, indexing marking devices arranged above said table surface for reciprocal movement in a direction normal thereto, a rotatable cam associated with each of said devices and normally at rest in a position permitting the same to be in an elevated position above said table surface, spring means urging said devices to said elevated position, and power driven means arranged to rotate said cams simultaneously and including a selectively operable one revolution clutch whereby said devices are lowerable to engage a mat arranged on said table surface.

'7. Apparatus for indexing mats used in the color printing art to insure that printing plates made therefrom will be registered, comprising a table surface adapted to receive a mat thereon, a plurality of pointers each arranged for selective adjustment to different locations over said table surface, manually releasable means holding each of said pointers in an elevated position above said table surface and comprising a pivotally mounted arm from one end of which the corresponding one of said pointers depends, spring means tending to pivot said arm to depress said pointer and detent means holding said arm in a tipped up position against the urging of said spring means, said detent means being released by manually depressing said arm so as to permit said pointer to engage a predetermined positioning mark on a mat arranged on said table surface, indexing marking devices arranged in a normally elevated position above said table surface, and means arranged to lower said devices into engagement with the mat.

8. Apparatus for indexing mats used in the color printing art to insure that printing plates made therefrom will be registered, comprising a table surface adapted to receive a mat thereon, at least three pointers above said table surface, independent means supporting said pointers for selective adjustment to different locations over said table surface, each of said means comprising a slide arranged above said table surface for horizontal movement transversely thereof, connected horizontal and vertical arms each adjustable as to its effective length to provide a support structure having one end mounted on said slide, a tip up arm connected at one end to one of said pointers which depends therefrom and pivotally mounted to the other end of said support structure, spring means tending to pivot said tip up arm to depress its pointer and detent means associated with the mounting of said tip up arm on said support structure and arranged to hold said tip up arm in a tipped up position against the urging of said spring means but releasable by manually depressing said tip up arm so as to permit its pointer to engage a predetermined 19 positioning mark on a mat arranged on said table surface, indexing marking devices arranged in a normally elevated position above said table surface, and means arranged to lower said devices into engagement With the mat. 5

References Cited n the file of this patent UNITED STATES PATENTS Name Date Number 20 Name Date Howe Jan. 5, 1901 Gran et al Feb. 13, 1912 Huebner June 13,1933 Fankboner Jan. 14, 1936 Walsh Nov. 23, 1937 Bungay May 7, 1940 Groome Apr. 18, 1950

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