US2895187A

US2895187A - Apparatus for casting stereotype printing plates

Info

Publication number: US2895187A
Application number: US573904A
Authority: US
Inventors: Chase Corson Walter; Krueger Glenn Nicholas
Original assignee: Miehle Goss Dexter Inc
Current assignee: Miehle Goss Dexter Inc
Priority date: 1956-03-26
Filing date: 1956-03-26
Publication date: 1959-07-21
Anticipated expiration: 1976-07-21

Description

July 21, 1,959 c.,w. CHASE ErAL APPARATUSFOR CASTING STEREOTYPE PRINTING PLATES e sheets-Sheet 1 SSN ` INVENTo. Cowon MM BY lwmz IW July 21, 1959 c. w. CHASE EIAL 2,895,187

. APPARATUS PoR CASTING sTI-:RROTYPE PRINTING PLATES Pild March 26. 195e 6 Sheets-Sheet 2 N INVENTORS. l A l BYMZZ//diQp/ @Wmv/fg,

`Ju`ly` 21, 1959 2,895,v1 87 APPARATUS FOR CASTING STERROTYPE PRINTING PLATES Filed March 26, V1956 c. w. CHASE ETAL s sheets-sheet s' INVENTORS. Camo?? ZMzZ/z me I' 2,895,187 APPARATUS PoR cAsTING sTEREoTYPE PRINTING PLATES Filed March 2e. 1956 c w. CHASE ETAL `July 21 1959 6 Sheets-Sheet 4 July 2l, 1959 f y c. w. CHASE ET AL 2,895,187

APPARATUS 'FOR CASTING STREOTYPE PRINTING PLATES Filed March 26. 1956 y I 6 Sheets-Sheet 5 JUZ Ply/V65? CLOSE To Ls To L51 Z July 21, 1959 c. w. CHASE ETAL 2,895,187

APPARATUS FOR CASTING STEREOTYPE PRINTING PLATES Filed March ze, 195e e sheets-sheet e Jja.

NVENTgRs.

United States Patent O APPARATUS FOR CASTING STEREOTYPE PRINTING PLATES Corson Walter Chase, Oak Park, and Glenn Nicholas Krueger, North Riverside, Ill., assignors to Miehle- Goss-Dexter, Incorporated, Wilmington, Del., a corporation of Delaware Application March 26, 1956, Serial No. 573,904

12 Claims. (Cl. 22-2) This invention pertains in general to apparatus for casting curved stereotype printing plates and, in particular, to such apparatus having a stationary, concave mold box and a convex plunger movable relative thereto to form a mold space and to aiford convenient removal of the cast plates. Y

The general aim of the invention is to bring about a very much simplified, rugged, and inexpensive construction for such plate casting apparatus which, nevertheless, is faster and more reliable in its operation.

Coordinate with that aim, it is an object of the invention to do away completely with an individually movable head ring, and the actuating linkage therefor, heretofore deemed necessary to close the bottom of the mold space formed between the mold box and plunger, thereby substantially eliminating the possibility of tins or ashings on cast plates.

A related object of the invention is the realization of an arrangement in which the bottom of the mold space is closed by a head ring integral or rigid with the plunger itself and which may be constructed to create a beveled bottom edge on the cast plates.

Concurrently, it is an object of the invention to provide a head ring which effects a more uniform and precisely controlled spacing between the mold box and plunger when the latter is in its closed position, to the end that successively cast plates are more uniform in thickness.

A related object is the provision of a head ring integral or rigid with the plunger and so constructed as to avoid overheating of the former when plates are cast in rapid succession.

Another object of the invention is to provide a linkage for moving the plunger in a manner such that a head ring rigid therewith clears the mold box during movement, but properly seats against the latter when the plunger is fully closed.

Still another object of the invention is to provide such an arrangement in which the head ring clamps a type matrix in the mold box when the plunger is closed, but does not slide or rub along the matrix before the latter is stripped from a cast plate. By this provision, the invention contemplates apparatus including matrix setting and stripping means automatically actuated as the plunger opens and closes in such a way that the matrix is not torn, wrinkled or otherwise damaged, thus permitting the same matrix to produce several cast plates in succession.

It is a further object of the invention to make possible the stripping of a cast plate from the plunger as the latter swings `to a horizontal position even though a recessed head ring rigid with the plunger prevents movement of the plate directly transaxially of the plunger.

Still another object of the invention is to construct a plunger so that it creates circumferential ribs on the undersides of cast plates, yet such that the cast plates may be stripped from the plunger with other than a direct transaxial motion.

g '2,895,187 Patented July 21, 1959 An additional object of the invention is to reduce the physical effort required to move the plunger between its closed and open positions by the use of power means controlled to prevent slamming of parts and to provide a constant pressure to hold the plunger in closed position.

Other objects and advantages will become apparent as the following description proceeds, taken in conjunction with the accompanying drawings, in which:

Figure l is a side elevation of plate casting apparatus embodying the features of the invention;

Fig. 2 is a plan view of the apparatus shown in Fig. 1;

Fig. 3 is an end elevation, partially in section, taken substantially along the line 3 3 in Fig. l;

Fig. 4 is a fragmentary vertical section through the mold box and plunger with the latter in its closed position;

Figs. 5 and 6 are plan views of the mold box with the plunger in its open and closed positions, respectively, particularly illustrating the construction and operation of automatic mat-setting means;

Fig. 7 is a diagrammatic side view of the mold box and plunger showing the motion imparted to the latterv by its movable linkage.

Figs. 8, 9 and l0 are diagrammatic stop motion views showing the plunger in its closed, partially open, and fully open positions, respectively, and particularly illustrating the operation of the plate-stripping means.

Fig. 1l is a diagrammatic illustration of a power Referring now to the drawings, it will be Ihelpful rst,

by way of setting the environment of the invention, to observe the major components of, and their functions in, plate casting apparatus of the type with which the invention is concerned. In general terms, the apparatus includes a stationary mold box 15 and a movable plunger 16, the latter being movably supported on two spaced frame members 18 extending forwardly from the mold box. The plunger is adapted to swing between a. vertical or closed position With respect to the box 15 and a horizontal or open position (compare Figs. 8 and 10). In its closed position (Figs. 5 and 7) the plunger defines with the box a curved mold space 19 open at the top to receive molten type metal. Seated against the box within the mold space is a type matrix 20 which creates type images or impressions on the convex surface of the curved plate when it is cast. When the plunger 16 is then moved to its open, horizontal position, the cast plate P is carried with it and swung to a horizontal position where it may be conveniently shifted into finishing apparatus (not shown) for shaving and trimming.

The mold box 15 is a relatively large, stationary, upright member having a concave surface 21 on its front side, the interior of the box containing uid passages or conduits for the circulation of coolants which carry away the heat of molten metal poured into the mold space. For the purpose of holding the exible matrix 20 rmly seated against the concave surface 21, the mold box 15 also has a vacuum manifold 22 adapted for connection to a suitable vacuum source (not shown) and leading to surface 21.

Because of the advantageous features afforded by the present invention, the mold box 15 may successfully be equipped with automatic mat-setting means, i.e., holders for flexible mats made of papier-mch, for example, which seats the mat against the surface 21 as the plunger is closed and holds the mat as the plunger pulls away during initial opening movement. As shown best in Figs. vand 6, aV mat-setting leaf 25 is disposed on either side of the concave surface 21 and pivoted to rock about a vertical axis by connection to a vertical pin 26. These leaves` extend over substantially the entire height of the mold box and are biased outwardly therefrom by torsion springs 2S (Fig. 6). For clamping the vertical edge of the mat 20; each mat-setting leaf 25 carries a slidable jaw 29 which may be opened and closed, for example, by la handle 29a to clamp the mat at its edge portions 20a. With the mat thus held to the leaves 25 by the jaws 29, it is moved between a forward position (Fig. 6) and a rearwardposition (Fig. 5) where it is held against the surface 21 by vacuum applied through the ports 24. The mat-setting leaves 25, are deflected against the force of their biasing springs 28 to the closed position illustrated by Fig. 5 as an incident to movement of the plunger 16 into the box Y `as will be explained in more detail be- As shown best in Figs. 2 and 3, the two side frames 18 areY quite simple in organization. Each forms a support resting on the floor and is bolted as at 30 to one side of the mold box 15, extending forwardly from the latter substantially vertical plane. On its upper edge, each of the frames 18 is shaped to define a guide rail 18a which may be of inverted V-shape. This guide rail 18a forms the principal support for the movable plunger 16 as will be explained below.

The plunger 16, sometimes called the core, is a large metal part having a convex surfaceZ, substantially semicylindrical, adapted to fit into the concave surface 21 off'the mold box 15. With this, the mold space 19 (Fig. 5) becomes substantially semi-cylindrical so that the cast plates are curved and fit readily on the cylinders of rotary printing presses of the type used in printing newspapers and magazines. The interior of the plunger 16 may be formed with passages for the circulation of liquid coolants, asis Well known. Along the edges of the outer or flat face of the plunger are fastened a pair of sliding bar brackets 34. These brackets may be suitably bolted di- Iectly tothe plunger' and carry a pair of sliding bars 35 whichY may be moved radially of the plunger after the latterris in its closed position to seal off the front edges of the mold space 19. Since the details `of the construction and actuation of the sliding bars 35 are well known inthe art, those details have not been illustrated here and need not be more fully described.

As explained previously, the plunger 16 is supported on the frame sides 18 such that i-t may be shifted toward and away from the mold box 15, and at the same time be tilted between a vertical and a horizontal position. Carried on the sides of the plunger are a set of four mat leaf actuators which may take the form of blocks 37 bolted to brackets 34. As the plunger swings to its vertical, closed position, therefore, the blocks 37 will strike the mat-setting leaves 25 and shift them inwardly against the bias of the torsion springs 28, so that the mat 20 held by the leaves is moved back against the concave Ysurface 21 where it is retained by suction against the ports 24. Y

ln accordance with the present invention, the bottom of the mold space 19 is closed by a head ring 4t) rigid or integral with the plunger itself, As here shown, the head ring is semi-circular in shape and held tightly to the underside of the plunger by a plurality ofmachine screws 41 (Fig. 4). So attached to the plunger, thehead ring l0-presents a ilange 42 projecting radially from the convex surface 32. The-mold box 15 at its lower -portion is fitted with an insert 44 which has a smallbead 46 projecting slightly from the concave surface 21. The flange 42 thus extends across the mold space 19 to engage the mat 20 and press it rmly in sealing relation against the bead 46. To positively locate the final position of the plunger 16 as it is shifted into the mold box 15, a bolster ring 47 is connected to the lower end of the mold box presenting a horizontally concave surface 48 (dat in a vertical direction) engaged by a shoulder 49 formed on the head ring 40. This thus precisely determines` the thickness of the mold space 19 each time the plunger is closed, and makes successively cast plates of uniform thickness. The engagement of the surface 48 and shoulder 49 also makes certain that the flange 42 positively clamps the matrix 20 against the bead 46, yet without such pressure that the matrix is cut or otherwise damaged. The horizontal step 50 on the bolster ring 47 serves as a support for the lower edge of the matrix 20 and accurately determines the vertical position of the latter.

When curvedV stereotype printing plates are mounted on printing cylinders, it is desirable to anchor their curved edges, and for this purpose, such curved edges are beveled, as is well known in the printing art. The upper curved edge of a printing plate (viewed as it is oriented immediately after casting and while still in the mold box) is beveled in the process of cutting olf the upper tail. It is highly desirable, however, to mold the beveled configuration for the lower curved edge of the printing plate at the time it is cast in order to eliminate a further machining or finishing operation.

In the present instance, this is accomplished by forming the upper surface of the head ring flange 42 with a recess 51 having one side thereof inclined from the axis of the plunger 16. That is, the inclined surface of the recess 51 makes an acute angle a with a line running parallel to the ax-is ofthe convex surface 32. As molten metal is poured into the mold space 19, therefore, the head ring flange 42 not only closes the bottom of that mold space but, due to the inclined recess 51, produces a beveled configurationV for the lower cunved edge E of the. resulting plate P. It may also be desirable to cast plates having adifferent beveled configuration at their lower edges` and to accomplish this result, head rings having various angles may be substituted for the ring shown in the drawings.

Thehead ring 40 in the exemplary form illustrated is a solidmetal piece while, as previously mentioned the plungeritself is provided with interior passages for the circulation of cooling fluids. Although heat in a large measure will be conducted from the head ring to the plunger and thusv removed by coolants circulated in the latter, it has been found that when a number of plates are cast in rapid succession the temperature of the head ring may appreciably exceed that of the convex surface 32. Underthat condition, the cast plates sometimes have a tendency to-stick to the ring 40` and cannot be easily stripped or lifted from the plunger.

To obvia'te this difficulty and supplement cooling of thehead ring by heat conduction to the plunger, means are vprovided to independently cool the head ring 40. In the preferred form shown, such supplemental cooling means take the form of a plurality of cooling ns 53 projecting from surfaces of the head ring 40 as best shown in Fig. 4. These cooling-tins facilitate heat transfer to the surrounding atmosphere so that even during rapidly repeated plate casting the head ring remains at about the same temperature as the convex surface 32. There is thus no danger that the lower edge of a cast plate will be soft when the upper portion has solidied; and the plunger may. be opened soon after molten metal is poured-into the mold-space without likelihood that the plate will stick rto the 'head ring 4t).

In prior plate casting apparatus of this general character, thevbottomfof the mold space formed between the mold box and the plunger has been closed by a separate head ring which was supported independently of the plunger and movable by a separate actuating linkage through a different path than that of the plunger as the latter was pulled to its .open position. This was deemed necessary in order to move\the plunger into the mold box without having it strike the concave surface of the latter and in order to get the beveled edge of a cast plate out of the inclined recess which produced it. Fins or flashing, produced by molten metal running between the plunger and head ring often resulted because the seal between the two had to be broken each time the plunger was opened, and thus frequently became ineffective. Y

Through the use of the fixed head ring 40, which thus becomes an integral part of the plunger 16, the need for a separate head ring is entirely eliminated, as well as the need for a linkage to move that head ring as the plunger is opened and closed. There is no problem, in the present case, with creating an effective seal between the head ring and the plunger since the bolts 41 may serve to draw the head ring tightly against the plunger to create a very tight and permanent joint at 52. There is no possibility, therefore, of a lin or flashing being produced on a cast plate due to molten metal running between the head ring and the plunger. The rm engagement of the surfaces 48, 49 on the bolster ring and head ring, respectively, produces accurate location of the plunger 16 with respect to the mold box 15. The mold space 19, and plates produced by it, are thus always of uniform thickness.

With the liange 42 of the head ring 40 projecting from the lbottom of the plunger 16, it might strike the mold box or mar the matrix as the plunger is moved between its open and closed positions, since the bottom end of the plunger must swing rearwardly with respect to the mid-portion of the plunger as the latter is tilted to a horizontal position. In keeping with another feature of the invention, this problem is obviated by a support linkage for the plunger constructed and arranged so that tilting of the latter takes place only when it is appreciably spaced from the mold box. In other words, the plunger is maintained substantially vertical or parallel to the mold box as it moves into or out of the latter, appreciable tilt ing of the plunger occurring only when it is sufliciently spaced to permit the head ring to clear both the concave surface 21 and the matrix 20.

As here exemplified, the plunger support linkage comprises a pair of support links 60 which are generally of cruciform configuration. As shown best in Fig. l, the links 60 are rigidly fixed on opposite sides of the plunger 16 to the respective sliding bar brackets 34 by a plurality of bolts 61. Preferably, the holes in the links 60 through which the lbolts 61 pass are elongated to permit some adjustment of each link longitudinally of the plunger in order that the relationship between the mold box and the plunger may be initially adjusted. Projecting outwardly from each bracket 60 are integral arms 62 (Fig. 2) which join to form a bearing 64 journaling a shaft 65 which, in turn, carries a guide wheel 66. These guide wheels are peripherally grooved to rest upon and roll along the guide rails 18a at the upper edges of the respective side frames 18. The guide wheels thus constitute a rolling pivot support for the plunger, since the latter may move horizontally along the rails yet pivot about the common axis of the two shafts 65.

For the purpose of effecting such translation of the plunger horizontally along the rails 18a and at the same time controlling the tilting of the plunger, the brackets 60 include depending bracket arms 68 which are, in effect, rigid with and form a part of the plunger itself. Extending between and journaled in the frame sides 18 at a point below the plunger is a rock shaft 69. A pair of levers or drop links 70 are disposed at opposite sides of the plunger 16 and connected at their opposite ends of the rock shaft 69 and the respective bracket arms 68. The lower ends of the drop links 70 are rigidly connected, as by a key at 71, to the rock shaft 69, while their, upper 6 ends are pivotally connected as by a pin 72 to the respective arms 68. As shown best in Fig. 1, the links 70 are preferably formed with T-shaped inserts 73 held in place by cap screwsY 74, the insert being apertured at 75 to receive the pivot pin 72. By the insertion or removal of shims 76 between the end of the link 70 and the heads of the inserts 73, the effective length of the arms 70 may be minutely adjusted when the apparatus is assembled to produce the desired location of centers described below.

The rock shaft 69 may be turned or oscillated through an angle of approximately 90 by any suitable means. The size and location of the parts, however, are such that the opposite ends of the drop links 70 are substantially vertical, that is, the axis of the rock shaft 69 and the axis of the pin 72 are substantially vertically alined, at the time that the plunger is vertical and within about one or two inches of being fully seated in the mold box 50. This relationship of the pivot points is most important and is particularly illustrated by Fig. 7. With the shaft 69 rotated in a counterclockwise direction from the position shown in Fig. l, the link 70 also rocks counterclockwise so that its right end moves upwardly and to the left in an arc around the axis of the shaft. As a result, the plunger 16 is bodily shifted to the left toward the mold box, the guide wheels 66 rolling along the guide rails 18a, while the plunger itself pivots about the guide Wheel shafts from a horizontal position toward a Vertical position. When the opposite ends of the links are substantially vertically alined, for example when the links lie along the vertical line in Fig. 7, the plunger 16 will be at or near its fully closed position. As here illustrated, the plunger is fully closed when in the position shown by solid lines and will be in the slightly retracted position shown by dotted lines in that ligure. It may be observed that as the links 70 are rocked through a small angle 0 in either direction from the vertical position represented by the line 75, the upper end of those levers will move principally horizontally through a variable distance labeled x, and will move only a very small, substantially negligible vertical distance as above shown by the variable dimension y. In result, therefore, the plunger 16 is not appreciably tilted or rocked about the guide wheel shafts 65 during travel between the two positions depicted in Fig. 7. This is most important, for it makes certain that the plunger Will not tilt appreciably until it has been withdrawn from the box 15 sutciently so that the head ring 40 clears the mold box.

The action can be demonstrated with reference to simple mathematical expressions. Assuming that the links 70 are initially in the vertical position represented by the line 75, and that they have an effective radius R, the vertical displacement of the pin 72, represented by the symbol y, may be expressed Similarly, the horizontal displacement of the pin 72 for a given angular dellection of the lever arms 70 from their vertical positions may be represented by the dimension x and expressed:

x=R sin 6 As the angle 0 is increased from zero in either direction from the line 75, the distance x increases rapidly; While the dimension y remains very small. For example, in one physical construction of the present apparatus, the plunger 16 may move through a distance of about 1% inches with the pivot pin 72 moving slightly less than 0.1 inch in a vertical direction. This produces practically no tilting of the plunger about the guide wheel shafts 65. As a result, the plunger is shifted substantially horizontally into and out of the mold box 15 over one or two inches of travel as it enters and leaves the latter. Further retraction of the plunger, however, results in it being tilted 7 over to the horizontal position as depicted in Figs. 9 and l0.

By so constructing the linkage for the plunger 16, several advantages accrue. First, the head ring 40 may be integral with the plunger 16 and yet not strike the concave surface 21 of the mold box 15 as the plunger enters or leaves the mold box. The integral head ring eliminates the possibility 'of flashings or ns being produced by rnolten metal running between the plunger and the head ring.

Direct abutment of the head ring against the mold box results in positive positioning of the latter to accurately define the mold space 19.

Due to the fact that the plunger 16 moves almost purely horizontally as it seats in or initially retracts from the mold box 15, the flange 42 on the head ring 40 approaches and leaves the matrix substantially at right angles to the surface of the latter. In clamping the matrix 20 against the bead 46V (Fig. 4), and in releasing the matrix from the bead, the head ring 40 thus does not tend to slide along the surface of the matrix. As the plunger opens, therefore, and the matrix held in the leaves 25 lags behind, the matrix is stripped from the cast plate without being torn, wrinkled, or otherwise damaged. The same matrix may be used to cast several plates in succession, and without manually replacing and adjusting the matrix in the mold box.

The invention includes, in combination with the rigid head ring 40 and the advantageous linkage comprising the rock shaft 69 and levers 70, a cooperating mechanism for lifting or stripping cast plates away from the plunger as the latter is moved to its open position. When the plunger is opened, and carries a cast plate with it to its horizontal position, it is desirable that the plate be elevated above the plunger so that it may be slid directly onto adjacent ways (not shown) and into a shaving arch (not shown).

With the inclined recess 51 in the head ring 40, it is diflicult to lift the plate P directly away from the plunger, i.e., in a direction transverse to the axis of the convex surface 32. The beveled curved edge E of the cast plate P would catch in the recess 51 and the plate would be deformed, especially while still very hot, in being forced out of that recess. To obviate this difficulty, plate stripperson eitherl side of the plunger are adapted to be shifted in a direction inclined to the axis of the latter, and in a direction away from the head ring.

As here shown (Fig. l), plate strippers in the form of bars 80 are movably supported on the opposite sides of the plunger 16 so that they may be retracted when the plunger is closed and elevated both axially and transaxially relative to the convex surface 32 as an incident to opening of the plunger. Each of the plate stripper bars 8i) has an upper surface 8l adapted to underlie the opposite straight edges of the plate P when the latter rests on the plunger surface 32. Serrations or teeth 82 may be cut in that surface for gripping engagement with the edges of the plate. Each of the bars 80 includes a pair of spaced ears 84 which are connected to the side of the plunger 16 in a manner to permit the bar to move simultaneously both radially and axially of the plunger producing a resultant inclined movement away from the head ring 40.

In the present instance this is accomplished by the provision of angled, camming slots 85 cut in the ears 84 and receiving camming pins 86 rigidly xed to the sliding bar brackets 34 which, as explained above, are fastened to the plunger itself. The upper and lower portions 85a, 85b of the camming slots run in a direction which is substantially vertical as viewed in Fig. l, or, in other words, in a direction transverse to the axis of the convex surface 32. The central portion 85C of each slot 85 is, however, inclinedfrom the vertical when in the position shown by Fig. 1 so that as the bar is shifted transversely 'to the axis of the convex surface 32, it also moves axially of thel latterand in a direction away from the head ringr40.

In order to automatically move the plate stripper bars to the position shown in Fig. l as an incident to movement of the plunger 16 to its horizontal, open position, and to let the bars 80 drop away from the convex surface 32 as the plunger is moved to its closed position, each of the bars 80 includes a central depending leg portion 88 which is adapted to engage stationary abutments supported on the inner sides. of the frames 18. As shown best in Fig. 3, a pair of Aabutment brackets. 89 are fixed to the respective side frames 18 and carry abutment rollers 90 rotatably mounted on supporting pins 91.

As the plunger swings to its vertical position (Fig. 8), the lower edges of the legs 88 swing away from the abutment rollers 90 so that the plate stripper bars 80 drop by gravity until the camming pins 86 are in the upper ends of the slots 85. The upper surfaces 81 of the stripper bars, therefore, are retracted from the convex surface 32 and permit the sliding bars 35 to close. As the plunger 16 swings toward its horizontal position, the lower edges of the legs 88 engage the abutment rollers 90 (Fi-g. 9,) and cause the stripper bars to move upwardly, the direction of motion being guided by slots 85 and the camming pins 86. By the time the plunger has reached its horizontal position (Fig. l0), the lower ends of the legs 88 remaining in contact with the rollers 90, the stripper bars 80 have been shifted upwardly relative to the convex surface 32 so that the pins 86 are in the lower ends of the slots 85. The position of the roller 90 is such that the bars 80 make contact with the plate P when the pins 86 are riding in the portion 85C of the slot 85 (Fig. 9).

Withthis movement of the stripper bars 80 relative to the plunger 16, the upper edges of the bars engage the lower edges of the cast plate P molded on the convex surface 32 as the plunger tilts to horizontal or plate discharge position. The stripper bars, therefore, lift the cast plate P bodily away from the convex surface 32, rst shifting the plate in a direction inclined to the axis of the convex surface and axially away from the head ring 40. That angular motion of the stripper bars, produced by the inclined slot portions 85C, corresponds generally to the angle a (Fig. 4) so that the plate P is lifted smoothly out of the head ring recess 51. Following the inclined movement of the plate P produced by the cam slot portions 85c, the slot portions 85b cause continued movement of the stripper bars 80 and plate P in a direction substantially perpendicular to the axis of the convex surface 32, until the plate occupies the position shown in Fig. l0 when the plunger is fully open.

With the cast plate P elevated from the plunger 16 as shown in Figs. 1 and l0, it may be slid onto adjacent ways (not shown) and into a shaving and cut-off machine (not shown). The latter is employed to shave the inner surface of the cast plate to a perfectly cylindrical shape, making the plate of uniform thickness. At the same time, the upper portion or tail of the plate is trimmed off. It is highly desirable that the cast plates have a series of axially spaced circumferential ribs on their inner cylindrical surfaces in order that the shaving operation need not remove metal from the entire surface but only from the ribs themselves. In prior practice, such ribs have been made of a relatively sharp V-shape in cross section, the included angle of the rib cross section being about 30. The convex surface of the plunger was formed with a series of axially spaced grooves therein to mold the ribs at the time a plate was cast, the sides of the grooves making an angle of about 75 with a line parallel to the axis of the plunger surface.

In the present instance, however, the completed plate P is not lifted directly axially away from the convex surface 32 for lthe reasons given previously, i.e., the plate is shifted at an angle away from the convex surface in order that itslower curved edge will be lifted freely out of the inclined recess in the head ring 40.

In accordance with another feature of the invention, provision is made to form ribs on the inner surfaces of cast plates in a manner such that they permit this lifting ofthe plate in a direction inclined axially of the plunger. For this purpose, a plurality of circumferential grooves 95 are formedin the convex surface 32, such grooves being spaced axially along the plunger and shaped to have one side wall thereof angled in the general direction of movement of the completed plate P as it is stripped from the plunger 16. As shown best in Fig. 4, each of the circumferential grooves 95 is shaped such that the sidewall 96 remote from the head ring 40 is inclined at an angle from parallelism `with the axis of the convex surface 32. The angle is preferably slightly smaller than the angle a of the inclined surface 51 in the head ring recess. It may be, for example, in the order of 30, while the angle a may be in the order of 45. The inclination of the plate stripper slot midportions 85C may be either the angle of the ring or the angle of the grooves but is preferably intermediate between the angle a for the recess 51 and the angle for the side ywalls 96, i.e., the inclination of the slot portion 85e is preferably between 30 and 45. With this arrangement, when the plate stripper bars 80 lift the cast plate P away from the plunger surface 32, the ribs r formed on the plate by the ,grooves 95 will slide freely out of those grooves.

Plate casting apparatus of the type here described is often used to produce a great number of plates in only a short time. The rush of translating a late-breaking news story into type and getting a newspaper on the street promptly may often require that some sixty curved stereotype plates be made in the course of a half hour. The plunger 16 is, of course, relatively heavy and manual movement of the same between its open and closed positions may require considerable physical effort on the part of a workman. It may result in fatigue so that the workman becomes careless as to other details and spoils many plates which would otherwise be satisfactory.

To assist the workman and eliminate fatigue, power means are employed to move the plunger 16 between its two positions, and to positively hold the plunger in its closed position so that entire reliance need not be placed upon the locking action of the sliding bars 35. In keeping with one aspect of the invention, means are provided for exerting power to remove the plunger through the final portion of its closing path and to `hold it in its closed position, while the same power means are adapted and controlled to supply all of the energy required to swing the plunger from its closed, vertical position to its open, horizontal position. It has been found highly advantageous to use only partial power closing since this preventsthe plunger from being swung too rapidly into the mold box 15. If that occurred, the inertia of the plunger might slam it into the mold box, possibly damagingv the mold box, plunger, or the type matrix.

In the specic arrangement here illustrated, a power actuator `in the form of a double-acting pneumatic ram 100 is connected to rotate the rock shaft 69. The ram 100 includes a cylinder 101 fastened to a. bracket fixed' to one of the side frames 18 (Fig. l) by a trunnion connection, and a piston rod 102 projecting from the cylinder for pivoted connection at 104 to a radius arm 105 rigidly connected at its opposite end to the rock shaft 69. When the piston rod 102 moves to the left as viewed in Fig. l, the plunger is shifted to its horizontal, open position as illustrated; on the other hand, when the piston rod 102 moves to the right, it turns the rock shaft 69 counterclockwise, rotating the arm 70 so that the guide wheels 66 roll to the left and the plunger is swung to its vertical position through the linkage previously described.

Energization of the power actuator or ram 100 is controlled such that it is eective in moving the plunger 16 toward its closed position only after the latter has closely approached the mold -box 15. For example, the actuator i is shifted to the right.

is controlled such that an operator must manually swing the plunger to within about three inches of being fully closed. At that point, the ram 100 is automatically energized and the piston rod 102 is shifted fully tothe right tomove Ithe plunger to its fully closed position. This prevents the plunger from slamming into the mold box. Conversely, the actuator 100 is energized so that it does all of the work in moving the plunger to its horizontal position. i

The foregoing is accomplished in the exemplary arrangement by employing two-position solenoid valves 106, 107 (Fig. ll) interconnected between the ports 101er, 101b at the opposite ends of the cylinder 101, an exhaust conduit 108, and a source of air pressure 109. Since the

valves

106 and 107 are substantially identical, the brief description of one will sutce for both.

' As shown in Fig. ll, the valve 106 includes a casing 110 having a rod 111 axially slidable therein and biased to the left by a compression spring 112. The casing 110 includes a rst port 113 which is straddled by second and

third ports

114 and 115. The rod 1,11 is formed with an enlarged portion 111a which normally blocks the port 115 and a second enlarged portion 111b which normally clears the port114 but covers Ithe latter when the rod Movement of the rod to the right also uncovers the port 115. 'Ihe

ports

114, 115 are connected respectively to Ithe exhaust conduit 108 and the air pressure source 109. For the purpose of shifting the rod 111 to the right against the bias of the spring, a solenoid winding 118 is located within the casing 110 in surrounding relation to an armature portion of the rod 111. That solenoid is controlled in a manner to be described below.

It will be apparent that with the rod 111 in the position shown, the port 101a at the right end of the cylinder 101 is vented to the atmosphere through the

valve ports

113, 114 and the exhaust conduit 108. However, when the solenoid 118 is energized and the rod 111 shifted to the right, the enlarged portion 111b covers the port 114 and port 115 is uncovered by the portion Illa so that air pressure is supplied through the valve ports 115 and 1-13 to the interior of the cylinder 101 on the right side of the piston.

The valve 107 likewise includes a casing 120 containing an axially shiftable plunger 121 biased to the right by a compression spring 122. In the normal position illustrated, the enlarged portion 121a of the plunger blocks communication with the air pressure source 109 so that the interior of the cylinder 101 on the left side of the piston is exhausted. However, when a controlling solenoid 128 is energized to shift the plunger 121 to the left, then air pressure is supplied from the source 109 through the casing to the interior of the cylinder 101 on the left side of the piston, causing the piston rod 102 to move to the right.

To control the

valves

106, 107 in a manner to energize the power actuator 100 as explained above, a first limit switch LS1 is fixed to the inner side of one of the frames 18, the switch having an actuating plunger LSlla spring biased outwardly and depressed by a lever 130 whenever a roller 131 is engaged by a pin 132 carried by one of the levers 70 (Fig. l). The location of the limit switch LS1 and the roller 131 relative to the rock shaft 69 and the arm 70 is such that the switch will be actuated just before the plunger 16 reaches a position fully nested in the mold box 15. Preferably, the pin 132 engages the roller 131 to depress the actuator LSla when the plunger 16 is about three inches in front of the mold box 15. Another limit switch LSZ is mounted on one of the side frames 18, having an actuator LSZa spring biased outwardly and disposed in the path of a lever 135 carrying a roller 136. The latter is disposed in the path of a projection 138 xed to one of the sliding bar brackets 34 on the face of the plunger 16. The projection 138 and roller 136 are relatively located such that the former will engage and II shiftthe latter (to actuate the switch LSZ) just as the. plunger reaches itsfully open or horizontal position as shown inFig. 1.

Limit switches LS1` and LSI-together with the solenoids 118 and128 for the control valves 106` and 107 are connected in circuit as schematically illustrated by Fig. 12. T heA limit switch LS1k has normally openk contacts LSlb connectedl inseries withY the solenoid 128 through normally closed contacts CRa of a control relay having a coil CR. This series connection is made across a voltage source represented by the power lines L1, L2. When the plunger is manually moved almost to its closed position, therefore, andthe limit switch LS1. is actuated to close the. contacts.LS1b, the solenoid 128 is energized to. .shift the valve plunger 121 so that air pressure is supplied to thev left side of the cylinder 101, causing the piston rodz 102'to move to the right. This results in the application of a kcounterclockvvise torque to the rock shaft 69 so that the plunger 16V is moved under the iniiuence ofthe actuator firmly into the mold box 15. Pneumatic pressure remainsin the left side of the cylinder 101 holding the plunger in its closed position; even if the locking `action of the sliding bars 35 should fail, therefore, the plunger 16 cannot open and spill molten metal.

When it is desired to shift the plunger 16 to its open position, the operator depresses a normally open push button switch S. The latter switch is connected in series across the lines L1, L2 with normally closed contacts LSZb of the switch LS2 and the solenoid 118 of the valve 10,6. Also connected in parallel with the solenoid 118 is the relay coil CR, the latter relay also having normally open contactsCRb in parallel with the switch S. When the switch S is depressed, therefore, the relay CR is energized immediately and seals in around the push button switch S through the contacts CRb. The contacts CRa. open to de-energize the solenoid 128, while a circuit is completed through the now closed contacts LSZb, the now closed contacts CRb, to energize the solenoid 118. The valvev 107is thus deactuated and the valve 106 actuated so that the left side of the cylinder is vented and the right side supplied with pressure fluid. Accordingly, the piston rod 102 moves to the left, exerting a clockwise torque on the rock shaft 69 so that the plunger 16. isrnoved out of the mold lbox 15 to its` horizontal position shown in Fig. l. When the plunger reaches its horizontal position, the projection 138 engages the roller 136 and actuates the limit switch LSZ, opening the normally closed contacts LSZb. This de-energizes the solenoid 118 and the relay coil CR so that the circuit is in its original condition, readyr to repeat the cycle of operation described.

We claim:

l. In apparatus for casting curved stereotype printing plates, the combination of a stationary upright, opensided mold lbox having a concave surface adapted to receive a type matrix, a frame extending horizontally from said mold box, a plunger having a convex surface adapted to define with said concave surface a mold space, means mounting said plunger on said frame to move between a vertical mold space-forming positio-n within said box and a horizontal position facilitating removal of a cast plate, said means including av rolling pivot connection between said plunger and frame and a lever pivotally connected at its opposite ends between said frame and plunger such that its opposite ends are substantially vertically alined when the plunger is Vertical and seated in the mold box, a head ring rigidly fixed to the bottom of the plunger and presenting a flange extending radially of said convex surface to close the bottom of the mold space, said flangek having a recess in its upper surface to shape the lower edges on cast plates, a plate lifter movably mounted on the side of said plunger to engage and support a cast plate, camming means between said lifter and plunger for moving the former axially ofthe latter when shifted in` a-l direction transverse. to the. longitudinal axis. of the plunger, abutment means. onthe frame engaged by the plate lifter as the plungerV is-movedv to its. horizontal position toshift the former. transversely to the longitudinal axis of the latter, and means defining a plurality of circumferential grooves in the. convex surface of said plunger with one side of each groove angled in the direction of movement of the plate lifterfrelative to theplunger.

2; In apparatus for casting curved stereotype printing plates, the combination comprising a stationary vertical mold box, a plunger movable between a vertical position adjacent the mold box to define a mold space and a forwardly tilted position, means for supporting saidV plunger such that it moves substantially horizontally and transverse to the longitudinal, vertical axis of said mold box as the former enters and leaves the latter, a head ring rigidly fixed to the lower end of said plunger and having a recess in the upper surface thereof, a plate lifter disposed along the side of said plunger, means for shifting said plate lifter at an acute angle relative to the longitudinal axis of the plunger as an incident to movement of the latter to its tilted position, and means defining a plurality of circumferential grooves in the surface of said plunger, each of said grooves having one side angled in the general direction of movement of said plate lifter relative to said plunger.

3; InY apparatus for casting stereotype plates, the combination comprising a stationary, upright, concave mold box, ya convex plunger adapted to define with said mold box a curved mold space, a head ring rigidly fixed to the bottom of said plunger and projecting therefrom to abut the mold box and close the bottom of said mold space, means for mounting said plunger to move between a lirstpositiony inV which' it is vertically disposed in mold spaceforming relation to said box and a second position in which it is shifted forwardly from said box and horizontally disposed to facilitate removal of cast plates, said means includinga pivot support for the plunger movable horizontally away from said lbox and a lever pivoted to a stationary point at one end and pivoted to said plunger at the other end such that said lever pivots are substantially. vertically alined when said plunger is seated in said box, whereby the plunger does not tilt appreciably as it entersL and leaves the box so that the head ring clears the box .duringl such, movement.

4. Inl apparatus for casting stereotype plates, the combination comprising a stationary mold box having an upright, concave surface, a plunger having a convex surface adapted to deiine with' said concave surface a curved mold space, a headv ring fast on the bottom of said plunger and presenting a flange projecting from said convex surface to close the bottom of said mold space, Isaid iiangeV having a recess in its upper surface shaped to produce a beveledendedge on cast plates, means mounting said plunger for movement between a vertical mold space-forming position. and a forwardly tilted position, a plate lifter movably mounted on said plunger, and means for shifting said plate lifter away from said head ring at an angle inclined to the axis of said convex surface as an incident to movement of the plunger to its tiltedvvposition, whereby cast plates are lifted away from the plunger without interference from said head ring.

5. In apparatus for casting curved stereotype printing plates, the combination comprising an upright mold box havingI a concave surface, a plunger having a convex surface and movable between open and closed positions relative to said mold box, and means for stripping a plate away from said convex surface in a direction inclined to the axis of the latter as an incident to movement of said plunger to its open position.

6. In apparatus for casting stereotype plates, the combination comprising a moldV plunger having a convex surface and movable between a vertical plate-casting position and Va tiltedplate-removing position, a 'head ring fast-at` thev lower end of saidplunger and projecting transversely to the mold forming surface of the latter, said head ring having an inclined recess in the upper surface thereof, said recess defining an inclined bottom for the mold space to create a beveled edge on cast plates, a plate lifter movably mounted on said plunger, means for shifting said plate lifter in a direction inclined to the longitudinal axis yof said plunger and in a direction away from said head ring as an incident to movement of the plunger to its tilted position, and said plunger having a plurality of circumferential grooves formed in its convex surface to create ribs on the undersides of cast plates, each of said grooves having one of its side walls remote from the head ring inclined generally in the direction said plate lifter is shifted.

7. In apparatus for casting steretoype plates, the combination comprising a mold plunger having a convex surface, means mounting said plunger to move between a first vertical position for the casting of plates and a second horizontal position for the removal of cast plates, a head ring rigidly xed to the lower end of said plunger and having a flange projecting radially from said convex surface, means defining a recess in the upper surface of said ange shaped to form a beveled edge on cast plates, means defining a plurality of axially spaced, circumferential grooves in said convex surface with the wall of each groove remote from said head ring inclined at an acute angle relative to the longitudinal axis of said convex surface, a pair of plate lifting bars, a pin and slot connection between said bars and the opposite sides of said plunger, a stationary abutment engaged by said bars as said plunger moves to its horizontal position, said slot having an angled configuration to cause said bars to thereby engage and simultaneously shift cast plates away from said head ring in a direction longitudinally of the plunger and transversely away from said convex surface.

8. In apparatus for casting curved stereotype printing plates, a plunger having a convex surface, a head ring rigid with one end of said plunger and having a flange projecting radially from said surface, there being a recess in said iiange presenting a boundary surface inclined at an acute angle relative to the axis of said convex surface, and means defining a plurality of circumferential grooves in said convex surface each of which has the side wall thereof remote from said head ring inclined at an acute angle relative to the longitudinal axis of said surface, so that cast plates resting on the convex surface may be stripped therefrom in a direction inclined at an acute angle to said axis.

9. In stereotype plate casting apparatus, the combination of an upright mold box presenting a vertical concave surface, a plunger having a convex surface adapted to define with said concave surface a mold space, a head ring rigidly fixed to the lower portion of said plunger and projecting radially from said convex surface to close the bottom of said mold space, and a frame extending horizontally from said mold box, a pivot support for said plunger translatable horizontally along said frame toward and away from said box, a shaft journaled in said frame, a drop link fast at one end to said shaft and pivoted at the other end to said plunger to rock the latter between vertical and horizontal positions as it is translated into and away from said mold box, said drop link and shaft being so arranged that the opposite ends of the former are substantially vertically alined and the plunger axis is substantially vertical when said plunger seats in said box so that the former moves substantially straight into and out of said box to avoid interference by said head ring, a double-acting power actuator operative on said shaft to move said plunger, means including a limit switch and means actuating the same when said plunger is manually moved from its horizontal position to a position closely approaching said box for energizing said actuator for partial power closing of the plunger and holding it in the closed position, and means for energizing said actuator in the opposite direction to effect powered movement of the plunger from it closed to its fully open position.

10. In stereotype plate casting apparatus, the combination comprising a stationary mold box having a concave surface, a plunger having a convex surface adapted to define a mold space with said concave surface, means supporting said plunger for movement between a closed vertical position within said mold box and a horizontal open position withdrawn from said mold box, said supporting means including a horizontally translatable pivot support, a rock shaft, and a drop link fixed to said rock shaft and pivoted to said plunger, a double-acting pneumatic ram operatively connected to said rock shaft, first means for energizing said ram only after said plunger has been manually shifted from its open position to effect partial power-closing of the latter, and selectively operable second means for energizing said ram in the opposite direction when the plunger is in closed position to effect full power opening of the latter, said first energizing means being maintained active to hold the plunger in closed position until said second energizing means is actuated.

11. In apparatus for casting curved stereotype printing plates, the combination with an upright mold box having a concave surface and formed at its lower end with an inwardly projecting step presenting a vertical surface, of a plunger having a convex surface and movable between open and closed positions relative to said mold box, a head ring rigid with the lower end of said plunger, said head ring having a matrix-clamping flange projecting radially from said convex surface and also having a vertical shoulder spaced inwardly from said ange, said shoulder being engageable directly with said vertical step surface to accurately determine the spacing between the convex and concave surfaces when the plunger is closed.

12. 'Ihe combination set forth in claim 11 and further including a plurality of cooling fins integrally formed on said head ring to facilitate the cooling thereof by transfer of heat to the atmosphere.

References Cited in the le of this patent UNITED STATES PATENTS 989,815 Scott Apr. 18, 1911 1,009,272 Wood Nov. 21, 1911 1,035,956 Furlow Aug. 20, 1912 1,174,978 Harm Mar. 14, 1916 1,509,078 Henzi Sept. 16, 1924 1,514,801 Smith Nov. 11, 1924 1,514,802 Smith Nov. 11, 1924 1,544,570 Gammeter July 7, 1925 1,569,491 Hopkins Jan. 12, 1926 1,623,991 Wood Apr. 12, 1927 1,786,629 Pepper Dec. 30, 1930 1,848,593 Wood Mar. 8, 1932 1,957,104 Gerrard et al. May 1, 1934 2,242,943 Clark May 20, 1941 2,464,051 Morin Mar. 8, 1949 2,484,907 Purcell Oct. 18, 1949 2,519,739 Butner Aug. 22, 1950 2,526,753 Huck Oct. 24, 1950 2,618,823 Perkon Nov. 25, 1952