US2079243A - Means for registering printing plates - Google Patents

Description

y 1937. L. w. CLAYBOURN 2,079,243

MEANS FOR REGISTERING PRINTING PLATES 2' Sheets-Shet 1 Filed Jan. 29,1935

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May 4, 1937. .w. CLAYBOURN v I MEANS FOR REGISTERING PRINTING PLATES Filed Jan. 29, 1935 Sheets-Sheet 2 Patented May 4, 1937 UNITED. STATES PATENT oFFieE MEANS FOR REGISTERING PRINTIN PLATES Leslie W. Claybourn, Milwaukee, Wis., assignor to C. B. Cottrell & Sons Company, Westerly, R. I., a corporation of Delaware Application January 29, 1935, Serial No. 3,941

8 Claims.

. on which matter to be transferred by impression is located.

The present invention is exemplified in connection with printing plates less than type high arranged to be supported on a base and to be positioned with relation tothe latter.

The invention is further exemplified as applied to fiat plates for fiat bed printing, although it is obvious that certain parts of the invention are also applicable to curved plates.

It ,is the object of the invention to provide novel means employable in positioning a printing plate in proper relation for printing; and, further, in properly positioning printing plates with relation to each other in making up a socalled. form, so that the printing surfaces of related printing plates are in correct relation to each other.

The invention is further applicable in socalled color printing, in which it is desired that the successive printing plates for the various colors used in printing colored subject-matter are correctly located with relation to each other, so that the printing lines of the printing plates for the various colors shall register accurately with each other in the successive printings.

The invention consists in novel means for attaining these objects and in novel parts and arrangements of parts for obtaining the results desired.

The invention consists further in providing a frame arranged to be definitely positioned with relation to a support for the printing plate or printing plates, the frame being provided with a linear indicator or linear indicators, exemplified as a string or strings which are shown as adjustable on the frame, the printing plate or printing plates. being shiftable with relation to such string or strings in order to bring marks with which the printing plate or plates have been provided into registry with the string or strings,

the plate or plates being fastened in such registered position; further, to provide gauges arranged to be definitely positioned with relation to the support for determining the locations of the strings; further, to provide automatic tensioning means for the strings; further, to provide novel means for ready convenience in shifting the support into and out of operative position; further, to provide novel means for supporting the frame respectively in operative and in retracted positions; and, further, to provide novel means for locking the control means for controlling the shifting of the frame.

The invention consists further in providing strings and means for positioning the same above a support for a printing plate or printing plates in connection with means for positioning the printing plate or printing plates in registry with the strings; and, further, in so arranging the parts that the adjusting means for the printing plate or plates may be manipulated through the spaces between strings.

In the drawings:

Fig. 1 is a plan view of the improved device, partly broken away.

Fig. 2 is a vertical section taken on the line 22 of Fig. 1, showing a detail of the pivot means for the string frame.

, Fig. 3 is a bottom view of a corner of the string frame, partly broken away, and partly in section on the line 33 of Fig. 6.

Fig. 4 is a front view of the same, partly broken away.

Fig. 5 is an end elevation of the same, partly broken away, showing the string frame in down or operative position and the operators supporting bench in full lines, and showing the string frame raised and the bench retracted in dotted lines.

Fig. 6 is a vertical cross-section, taken on the line 6-6 of Fig. 1, showing the releasable supporting means for the string frame, partly broken away.

Fig. '7 is a horizontal section of the same, taken in the plane of the line 'l-'l of Fig. 6.

Fig. 8 is a vertical section of the same, taken in the plane of the line 8--8 of Fig. 6.

Fig. 9 is a plan view of the rocking guide for the supporting rod.

Fig. 10 is a vertical section, taken on the line Iii-l0 of Fig. 4, showing a detail of the supporting means for the leaning bar.

Fig. 11 is a cross-section of the same, taken in the plane of the irregular line H-H of Fig. 10.

Fig. 12 is a vertical section of a detail, taken on the line l2--|2 of Fig. 1, showing the frame structures and their mountings, and the means for mounting the gauge with relation thereto, partly broken away.

Fig. 13 is a front elevation of one of the automatic tensioning means for the string, partly broken, away.

Fig. 14 is a cross-section of the same, taken on the line |4|4 of Fig. 13, and partly broken away.

Fig. 15 is a vertical section of a detail of the removable bar of the support, taken on the line ||5 of Fig. l, and partly broken away.

Fig. 16 is a vertical section of the gauge clamping means, taken in the plane of the line |6--|6 of Fig. 12.

Fig. 1'7 is an enlarged plan detail view illustrating the registering means, and partly broken away.

Fig. 18 is a perspective view of an exemplifying printing plate supplied with register marks; and,

Fig. 19 is a vertical section of a modification of the means for supporting the string frame in raised position, and taken on a line corresponding to line 6-3 of Fig. 1.

An exemplifying printing plate 2| (Fig. 18) is provided with register marks 22, for example as explained in Letters Patent of the United States No. 1,839,866, issued January 5, 1932, to me. The printing plates are shown rectangular, but they may be of other form, the register marks at the respective sides and ends of the printing plates however being in crossing planes perpendicular to each other intersecting at the middle portion of the printing subject, so that the printing lines on all the printing plates in similar positions register with each other, as in color printing.

A stand 23 includes a table 24 and legs 25 connected by suitable cross-braces 26 and forming a rigid structure. The table is preferably of metal and is accurately level.

Marginal bars 21, 28, 29, and 30 are provided for the table, the bar 21 being exemplified as the rear bar, the bar 28 as the front bar, and the bars 29 and 35 as the side bars. (Fig. 1). These bars, which may also be termed abutments or ridges, are positioned with relation to the table so that the front bar and the rear bar are at true right angles to the side bars, to form a rectangular space 3| between the bars.

The rear bar and the side bars are preferably fixed to the table, and the front bar is preferably removable for ready insertion and removal of the movable support for the printing plates. The rear bar and the side bars are preferably fixed to the table by means of screws 35, one of which is shown in Fig. 12, a suitable number of these screws being employed for rigidly secur ing these bars to the table.

Each of the ends of the front bar 28 (Figs. 1, 15, and 17) is provided with a dove-tail tooth 36, received in a dove-tailed recess 31, the front end of each of the side bars being provided with such a recess. The front bar is at suitable intervals provided with positioning pins 38 fixed therein and received in corresponding positioning holes 39 in the front marginal portion of the table.

These bars are rigid, for instance, of steel, and the releasable bar is releasably held in accurate position by the locking means at its ends and a suitable number of the positioning pins between its ends in such manner that outward pressure upon the bar is resisted, and the bar may be readily raised fordisconnecting it from the table, and readily replaced in operative position on the table.

The releasable bar when in release position is for convenience laid upon brackets 39 extending from the front of the stand. (Figs. 1, 4, and 5).

Each of the margins of the plate space on the table is provided with a gauge 4|. (Figs. 1, 12, and 17). These gauges are shown longitudinally adjustable on the respective bars, and as comprising scales 42 graduated in inches, the graduations having their beginning or zero mark at the left in the front and rear bars and at the rear in the side bars, so that opposite scales are accurately positioned with relation to each other in order that given values on opposite scales register with each other across the table.

Each of the scales is mounted on a slide 45 and is fixed to the slide, as by screws 45 (Figs. 12, 15, and 17). Each of the bars is provided with a groove 4! forming a guideway in which the slide is located for lengthwise movement. Gibs 48, 49 are secured to the bar, the inner margins of the gibs overlapping the margins of the slide for cating the slide, the gauge being shown narrower than the slide. The gibs are secured to the bars by means of screws 55 at suitable intervals lengthwise of the slides. Stops 44 are suitably fixed to the bars at the respective ends of the guideways for holding the slides endwise in their guideways. (Figs. 6, 8, 15, and 17).

The slides are clamped to the bars respectively when positioning of the slides has been effected, shown accomplished by providing a recess 5| between the bar and one of the gibs, the recess being shown in the bar in Figs. 12 and 16, a clamp screw 52 being journaled in the gib and threaded into the bar and having threaded connection 53 in the bar. This screw preferably has a socket 5 1 rectangular in cross-section and arranged to receive the usual turning nib of the usual key employed for positioning the register hooks for registering the printing plates.

When any of the slides has been positioned, the clamp screw 52 is turned for clamping the slide in adjusted position and thereby clamping the scale fixedly to the table, the clamp screw being released when another adjustment of the scale is desired.

The form to be registered is located in the enclosure 3| between the bars about the table. The form exemplified comprises a chase 6| and a base 62, suitably fixed in desired position therein and arranged to receive printing plates, exemplified at 2|. The chase has sides 63, 64 and ends 65, 66. The side 93 is the advancing side when the form is in the printing press and the end 65 is the end of the form toward the operators side of the printing press, or corresponds to the position of the side guide for the sheet in the printing press, these being the side and end from which measurements are made in locating the printing plates on the base. The base is pressed toward said side and end in the chase by means of suitable clamping furniture exemplified at 61, 68.

When placing the chase on the table the front bar 28 is removed, the chase with its base clamped therein being slid upon the table and the front bar then replaced.

The removable support for the printing plates, exemplified as the base, is clamped definitely on the table, which forms a support for the base, between the bars and is suitably positioned in the enclosure for most convenient operation of the registering means hereafter described. The form is shown positioned by suitable pieces of furniture 1|, 72 and suitable clamping quoins 13, 14. When type-high printing plates are being registered they are supported and positioned directly on the table.

Crossing strings 16, T! are positioned above the table. They are shown mounted on a string frame 15. The strings are adjustable laterally and are arranged to have tension applied thereto for definitely positioning the same. These strings may be cords or lines made of yarn or may be wires or strands of suitable material, but are preferably flexible and arranged to have tension applied thereto so as to draw the strings tight across the plate space. The strings are linear indicators to indicate the desired positions of the printing plates.

The string frame is a rigid structure and when in operative position is received about the bars of the table for having the base and the printing plates thereon located between the walls of said frame, in order that the strings may extend above and be proximate to the scales and the printing plates, although without interference therewith, so that the register marks 22 on the printing plate may be accurately positioned with relation to the strings on the string frame.

The string frame is a rigid structure, its sides and ends being preferably composed of square tubing I8 (Figs. 1, 3, 6, and 12). Corner pieces 19 are provided for the string frame, these corner pieces having square tongues 80 received in the ends of the tubings and fixed therein by being riveted thereto.

The string frame is movable with relation to the table, being shown pivoted at its rear corners on shoulder bolts 05, threaded into threaded lugs 86 fixed to the table, the rear corner pieces being provided with bearing lugs Bl, the bearings of which are journaled on the shoulder bolts. (Figs. 1 and 2.) The bearing lugs are accurately positioned in axial direction by having the inner faces thereof accurately guided by the outer ends of the threaded lugs on the table and by flanges 88 of the shoulder bolts. The front margin of the table is provided with positioning pins 89 at its respective ends received in corresponding positioning holes 90 in the string frame when the string frame is lowered into operative position with relation to the table. (Figs. 3 and 6.)

The string frame is also preferably latched with relation to the table, as by being provided with a supporting rod 0| at each of its elevating corners. (Figs..3, 5, 6, 7, 8, and 9.) Each of these supporting rods has pivotal connection with the string frame, as by having threaded connection 92 with a pivot pin 93 journaled in a bearing 94 of the front corner block of the string frame. The pivot pin is held axially by a flange 95 and contact of the rod with the bottom of a recess 96 in the corner block for accommodating the rod.

A latching means for the rod comprises a latch stem IOI, (Figs. 6, 7, 8, and 9), having a head I02 provided with a latching tooth I03 and urged toward the supporting rod by a spring I04 in a ho1eI05 in the table, the spring being located between the head I02 and a bearing plug I06 fixed to the table. The stem IiiI is prevented from turning by a key I01 between it and the bearing plug I06.

The supporting rod is axially movable and tiltable in a hole I08 in the table, and is guided by a pivoted bearing pin I09 in a hole H0 perpendicular to the hole I08. This bearing pin isprovided with a flange I I I, received in an enlargement I I2 of the hole H0, and is held axially in the hole by a closing plate II3 screwed to the table by screws II4. This pivoted hearing is provided with a hole H which forms a guideway for axial movement of the supporting rod.

The side of the bearing pin is provided with a recess IIB, into which the head I02 projects, the recess having an extension II'I through the side wall 'of the hole II 5, (Fig. 9), so that the latch I03 may extend therethrough into an annular groove I I8 in the supporting rod for latching the string frame in down position, it being understood that there is one of these latches at each end of the front of the string frame. Sufllcient of the wall of the hole I I5 in the pivot bearing pin I09 remains after provision of the recess IIS and its extension II! to insure lateral guidance for the supporting rod.

The latching means for the supporting rod are released by a releasing shaft IZI journaled in the bearings I22 on the table and having eccentric connection with the latch stem IOI by providing the latch stem with an outer collar I23 fixed thereto by a pin i2 3, (Figs. 1, 4, 6, and '7). The collar has a recess I25, the front wall of which is received in a recess I26 in the rock shaft I2I, the latter recess permitting the latch pin to move inwardly into the latching groove in the supporting rod, and forming a cam face at the end of the rocker rod in that the outer periphery of the rocker rod engages the front wall I21 and moves the latching pin outwardly when the rocker rod is rocked for disengaging the latch pin from the supporting rod. The rocker rod is provided with operating handle I28.

The lower end of the supporting rod is provided with a further annular groove I29, (Fig. 6), into which the latch tooth I 03 is received when the string frame is raised on its pivot into up-position. The lower end of the supporting rod is provided with a flange I30 arranged to engage the lower end of the wall of the hole II5 to prevent abnormal raising of the string frame. The string frame is provided with a handle I3! for raising and-lowering the same.

If desired, the latching means may be provided with an interlock to prevent accidental rocking of the rocker rodand release of the latch connection with the lower end of the supporting red when the string frame is in raised position. An exemplifying means for this purpose is shown in Fig. 19, in which the latching tooth takes the form of a latching loop I03, and the lower annular slot in the supporting rod is replaced by a recess I29 having an upward extension !32, forming a tongue I33, in interfering relation with the cross-portion of the loop which has entered this recess automatically upon the raising of the string frame. This relation of parts locks the rocker rod in latching position, and initial manual raising of the string frame by the operator so as to raise the locking tongue I33, out of obstructing relation with the cross-portion of the latching loop, is necessary before the rocker rod can be rocked for release of the latch.

The strings I0, T1, are supported by. holders I38. (Figs. 1, 4, and 5.) These holders are shiftable laterally and 'are arranged to be held in shifted or adjusted positions. They are provided with means for tensioning the strings so that the strings are drawn taut between opposite bars for providing a right line adjustment between such opposite bars perpendicular to the opposite bars. The printing plates are adjusted so that the register marks thereon register with these strings.

The strings are preferably arranged as close as possible to the printing surfaces of the printing plates while preferably out of contact therewith so that the printing plates may be shifted without disarrangement of the 5 strings. The strings are adjusted according to the graduations on the scales 42 on the encompassing bars or abutments of the table.

Each of the string holders comprises a slide I 4| slidable lengthwise of a guideway I42, there be ing one of these guideways extending lengthwise along each margin of the support. (Figs. 12, 13, 14, and 1'1). The guideway is shown as a dovetailed strip extending along the outer wall of each of the hollow bars of the string frame.

The slide includes a guideway complernental to the guideway I42, and is shown comprising a dovetailed groove I413, one of the walls of which is shown on a gib IN. The slide is arranged to be clamped in suitable adjusted positions.

For accomplishing this the gib has a fulcrum lug I45 on which it is tilted to draw the guideway edge of the gib toward the slide for clamping it to the dovetailed tongue I42, as by means of a shoulder screw I46, having a shoulder I41 bearing upon the slide and threaded connection I48 with the gib, the shoulder screw being provided with a knob I 59 for rotating the same.

The slide is provided with bearing lugs i5I, I52, forming bearings in which a pivot pin I53 is located. A spiral spring I54 is coiled about this pin. One end of the pin is provided with a cross slot I55 in which one bent end of the spring is located.

An arm l58 has a bearing I59 about the pin. It is provided with a hole I66 in which the bent other end of the spring is located. The other end of the pin is provided with a cross-pin IEI received in opposite ones of crossing slots I62 in the end of the bearing I52 for adjusting the tension of the spring. The arm has a shoulder I63.

The arm is provided with a clamp m5 comprising jaws which are normally resiliently separated and having a slot I 66 therebetween in which the string is received and clamped in adjusted positions by means of a shoulder screw l51, having a shoulder I68 bearing upon one of the jaws and having threaded connection I69 with the other of the jaws. It further has a knob I10 for rotating the same. I The tension of the spring I54 is so adjusted and the string clamps are so clamped at positions lengthwise at the respective ends of the string, that the clamps at the respective ends of the string at opposite margins of the string frame act together to draw the string taut across the frame in order to form a right line string which extends accurately crosswise of the frame. The string slides may be accurately shifted lengthwise of the scales to locate the respective taut strings into accurate registry with given dimensional values on the scales. The slides are shifted lengthwise of their guides by being manually slid along the same, and by being tapped in one direction or the other for determining their final accurate positions, whereupon they are clamped in such adjusted positions. The shoulder I63 strikes the slide MI to prevent undue retracting movement of the arm I58.

The respective ends of the device are provided 70 with supporting brackets I1I including guide bars I 12 extending along the respective ends of the table. (Figs. 1, 4, and 5). The bars support a bench I14 comprising a leaning board I15 extending across the table and having legs I16 provided with supporting shoulders I11 and guide shoulders I18 to hold the bench on the guide bars and to permit the bench to be moved crosswise of the table, for locating the bench in convenient positions so that the operator adjusting the printing plates may lean upon the same when bending over or lying above the printing form during adjustments of the plates on the base and during registering of the printing plates. Each of the guide bars I12 is provided with a stop I19 at each end of the guideway for preventing sliding of the bench off of the guideway.

Each of the margins of the table may be provided with a protective bar IBI, (Figs. 1, 4, 5, 10, and 11). One of these is shown at the front and one at the rear of the table. The guide bars I12 may serve similar protective purposes at the respective ends of the table.

Each of the protective rods is provided with an arm I82 at each end thereof, pivoted on a pin I83 in lugs I86 on a pad I85 secured to the frame. The protective rod may be placed in interfering or up-position, so as to extend in front of the string slides and protect them from contact by the operator when leaning over the table.

The protective rod may be held releasably in interfering position and may be retracted if desired. Each of the arms I82 is provided with a link I86 pivoted to the arm on a pin I81 outside of the endwise limit of the bearing lugs I84. Each of the links passes through a hole I88 in a rockable guide I89 rockable in a bearing I90 and held in endwise relation by having a flange I on one end of the rockable guide engage one end of its bearing and by having the link contact the other end of its bearing. The link passes through a slot I9I in the pad I85 and in the front skirt of the frame. A helical spring I92 is located about the link, one end of the spring bearing upon a flattened side I93 of its rockable guide and its other end bearing upon lock-nuts I94 threaded to the threaded inner end of the link.

The spring urges the arms and the protective rod toward the frame when the protective rod is swung upwardly on the pivots of its arms, and when it is swung downwardly so as to be out of the way. Movement of the protective rod when in tip-position toward the string holders and their guide is limited by contact of the arms with the pivot bearing I98, and inward movement of the protective rod when in down-position is limited by its ends contacting the legs of the frame.

In making up the exemplified form for printing, the positions of the plates are determined by the size of the sheet to be printed, the location of the printing on the sheet, the spaces or margins between the plates, and the margins between the groups of plates and the edges of the sheet.

It will be assumed that the side a of the form (Fig. 1) is the advancing side during printing by a printing couple including a fiat bed and a tympan cylinder, and that the sheet at such side is gripped by the grippers on the tympan cylinder. It will be further assumed that the end b of the printing form is the end toward the operators side of the printing press, and is the end from which measurements are made for positioning the plates lengthwise of the form.

At the gripper biting edge of the sheet there is what in printing parlance is called a dead line, denoting the line of the extreme outer or biting ends of the grippers, which would be in interference with any printing surface when in printing position, and out of range of which all printing surfaces must be placed to avoid injury to the same. i

One of the strings c on the string frame is placed in registry with this dead line, and the scales at the respective ends of the table are so adjusted that preferably the zero marks on thesev scales are in registry with this strin-g.- Other strings extending in similar directions are then adjusted to register with predetermined distance points on the end scales from the dead line string c, the number of strings so adjusted being determined by the number of rows of plates employed. Four such-additional parallel strings d are employed in the present exemplification, for positioning the four rows of printing plates extending lengthwise of the sheet. The strings extending crosswise of the form preferably'include a marginal string e, which is positioned to register with the position of the edge of the sheet at the operators side of the press. Additional strings f are provided for each set of crossingly arranged plates. 7

Thescales along the front and rear margins of the table are adjusted so that preferably their zero marks register with the marginal string e. The others of the strings f are set at predetermined distances from said marginal string, depending'upon the desired positions of the plates, the strings being adjusted to such distances according to the graduations on the scales 42 at the front and rear of the table.

The graduations of the scales 42 may be in inches or other denominations of linear measurement, and in practice have very small subdivisions, for accuracy in setting the strings. Any other mark than zero may be placed in registry with the first string lengthwise and crosswise of the form, depending onthe'number of the printing plates and the desired positions of the same.

Other strings may be employed to define the other edges of the sheet with relation to the printing form. r

The locations of the strings for locating the plates are in practice determined according to the dimensions given on a lay-out sheet, these dimensions corresponding with the desired locations of the register marks on the printing plates when the printing plates are properly located in the printers form.

In further explaining the operation of this improved device it will be assumed that printing plates less than type-high are employed and that the plates are positioned on a base provided with usual diagonal undercut grooves 201 in which usual and suitable plate-holding register hooks 202 are adjustable by a suitable register key 203 (Fig. 12) for adjustably shifting and locking the plates for instance, as disclosed in Letters Patent No. 1,486,323, issued to me March 11, 1924, for printing plate securing means. The register key in the present instance extends past the plane of the register strings into the register hook.

When type high printing plates are employed, the printing plates may be adjusted in the chase and secured in the chase in adjusted positions, the chase having been previously placed upon and secured to the table, the table serving as a support for the plates. V

The protecting rod I8! is lowered and the front marginal bar 28 is removed and temporarily laid upon its brackets 39. The string frame 15 is raised by means of its handle I3l, the latches for the supporting rods of the string frame having been released by rocking of the rock-shaft l2! by means of one of its handles I28. The latches having been released andthe string frame raised, the latches engage the lower notches 129 in the supporting rods for holding the string frame in raised position. I

The chase with its base secured therein is then slid upon the table 24 from the front between .the end bars or abutments at the respective ends of the table, and the front bar or abutment is replaced. The chase with its contents is thereupon fixedly positioned on the table. The protecting rod I8! is thereupon raised.

When the chase and its contents have been placed upon the table and fixedly secured thereto, the string frame is lowered into operative position as by having the operator grasp the handle 13! thereof for manually supporting and lowering the string frame, the operator also releasing the latch I93 by operation of one of the handles I28. In the form shown in Fig. 19 the string frame is locked in raised position to prevent accidental release of the latches.

In practice, the walls of the string frame are preferably outside the walls of the recess in which the printing plates are located, the scales extending along the inner sides of the walls of the string frame and being of a height close to but slightly lower than the level of the strings when the string frame is in operative position. The scales are located so that the strings may be positioned with relation thereto. They are exemplified as supported on the table. The printing surfaces of the printing plates are also on a level close to but slightly below the level of said strings and the registering marks 22 are on the level edges 204 of the printing plates close to the level of the printing surfaces thereof. The strings are preferably in a plane parallel to the printing faces of the printing plate and just free of contact with the scales and printing plates. The strings are preferably quite thin or of small diameter so that they form sharp well-defined guides extending across the printing plates;

The printing plates are shiftable on their supports so as to locate their sharply defined register marks respectively at the top and bottom and at the sides of the printingplates, in sharp registry with the crossing register strings. The plate locating device or register hooks are manipulated through the spaces between the register strings by suitable register hook keys 203.

In order to aid the operator in readily sighting the locations of the register marks on the printing plates with relation to the register strings, which sighting is in a direction perpendicular to the face of the printing plates, the operators bench I14 is provided so that the operator may lean over the plates being registered without contact with or disturbance of the strings or the plates, and so that he may direct his vision upon the respective strings and the respective register marks in lines perpendicular to the surface of the printing plates. The bench is shiftable tovarious positions above the printing plates so that the operator will find a convenient support for reaching any part of the printing form. I

After the register strings have been set, successive printing plates, in successive printing forms for successive colors in multi-color printing of the same subject may be registered, with the assurance that registry of the printing lines on successive plates .Will register with each other in printing.

This improved device provides simple and effective means readily and quickly manipulated by which accurate registry of printing plates is obtained.

I claim:

1. The combination, in printing plate registering means, of a table on which to register the printing plates, a swinging frame comprising a protective rod swingable respectively above and below the level of the supporting surface of said table respectively for maintaining distance of the 10 operator with relation to said table and for placing said protective rod in inoperative position and a supporting arm for said protective rod at each end thereof, one of the ends of said arms attached to said rod and the other ends of said arms pivoted to said first-named table, spring means between said swinging frame and said table to urge said protective bar toward said table, and a stop to limit approach of said swinging frame toward said table.

2. The combination, in printing plate registering means, of atable having a supporting surface on which to register the printing plates, a swingable frame comprising a protective rod for maintaining distance of the operator with relation to said table and a supporting arm at each end thereof, one of the ends of said arms attached to said rod and pivots between the other ends of said arms and said table, said swingable frame swingable upwardly on said pivots to locate said protective rod above the level of said supporting surface and downwardly on said pivots to locate said protective rod in inoperative relation under the level of said supporting surface, a link one end whereof is pivoted to one of said arms, a rockable guide provided with a bearing in which said link slides, said rockable guide journaled in said table, and a helical spring about said link between said rockable guide and the other end of said link to hold said swlngable frame in upwardly swung and in downwardly swung positions.

3. In a printing plate registering means, the combination of a table for supporting a form of printing plates to be registered, a string frame comprising frame members at the margins of said table and strings therebetween for registry of the printing plates of said form supported by said table, the rear of said string frame hinged to said table, a supporting rod whose upper end is at- 0 tached to the front portion of said string frame, a rotatable bearing journaled in said table with which said rod has slide connection for guiding said rod, a latch on said table for said rod to hold said rod and said string frame in raised relation,

and releasing means for said latch.

4. In a printing plate registering means, the combination of a table for supporting a form of printing plates to be registered, a string frame comprising frame members at the margins of said table and strings therebetween for registry of the printing plates of said form supported by said table, the rear of said string frame hinged to said table, a supporting rod whose upper end is attached to the front portion of said string frame,

a rotatable bearing journaled in said table with which said rod has slide connection for guiding said rod, a latch on said table for said rod to hold said rod and said string frame in raised relation, said latch movable into said rotary bearing for coaction with said rod, and releasing means for 5 said latch.

5. In a printing plate registering means, the combination of a table for supporting a form of printing plates to be registered, a string frame comprising frame members at the margins of said 10 table and strings therebetween for registry of the printing plates of said form supported by said table, the rear of said string frame hinged to said table, a supporting rod whose upper end is attached to the front portion of said string frame, 15 a rotatable bearing journaled in said table with which said rod has slide connection for guiding said rod, a latch on said table for said rod to hold said rod and said string frame in raised relation, said rod provided with an interlocking keeper for 20 said latch engaged with said latch by descent of said rod, said interlocking keeper requiring raising of said rod to release the interlock of said keeper for releasing said latch, and releasing means for said latch. v

6. In a printing plate registering means, the combination of a string frame, a guide thereon extending lengthwise of a margin thereof, a slide slidable lengthwise on said guide, an arm pivoted to said slide and comprising a string clamp, a :50 string clamped at one of its ends by said clamp and extending crosswise of said frame, holding means on the opposite margin of said frame for the other end of said string, and resilient means between said slide and said arm to resiliently urge 35 said clamp outwardly from said frame to stretch said string. 7

'7. In a printing plate registering means, the combination of a string frame, a guide thereon extending lengthwise of a margin thereof, a slide .40 slidable lengthwise on said guide, an arm pivoted to said slide and comprising a string clamp, a string clamped at one of its ends by said clamp and extending crosswise of said frame, holding means on the opposite margin of said frame for the other end of said string, resilient means between said slide and said arm to resiliently urge said clamp outwardly from said frame to stretch said string, and holding means for said slide to hold said slide in selective positions lengthwise of n said guide.

8. In a printing plate registering means, the combination of a string frame, a guide thereon extending lengthwise of a margin thereof, a slide slidable lengthwise on said guide, an arm pivoted 55 to said slide and comprising a string clamp, a string clamped at one of its ends by said clamp and extending crosswise of said frame, holding means on the opposite margin of said frame for the other end of said string, resilient means between said slide and said arm to resiliently urge said clamp outwardly from said frame to stretch said string, and means for limiting such urged movement of said arm.

LESLIE W. CLAYBOURN. 65

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