US2619694A - Pump operating and control mechanism for stereotype plate casting machines - Google Patents

Description

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I. TORNBERG ET A PUMP OPERATING AND CONTROL ME STEREOTYPE PLATE CASTING MKCHINES Dec. 2, 1952 Filed July 16, 1949 1952 I. TORNBERG ETAL 4 PUMP OPERATING AND CONTROL MECHANISM FOR STEREOTYPE PLATE CASTING MACHINES Filed July 16, 1949 7 Sheets-Sheet 2 INVENTORS lS/DO/P TORNBEIPG and ATTORNEYS 1952 TORNBERG ETAL 9,6

PUMP OPERATING AND CONTROL MECHANISM FOR STEREOTYPE PLATE CASTING MACHINES Filed July 16, 1949 7 Sheets-Shef s ATTORNEY Dec. 2, 1952 I. TORNBERG ETALZ PUMP OPERATING AND CONTROL MECHANISM FOR STEREOTYPE PLATE CASTING MACHINES Filed July 16. 1949 7 Sheets-Sheet 4 ATTORNEYS d n 4 v a 9 5 5 W 6, a M 5 9 m m & 2H 2 a w MA m ls T y 7 D UY lfiB PM l. TORNBERG El AL PUMP OPERATING AND CONTROL MECHANISM FOR STEREOTYPE PLATE CASTING MACHINES Dec. 2, 1952 Filed July 16, 1949 Dec. 2, 1952 1. TORNBERG ETAL 2,519,694

PUMP OPERATING AND CONTROL MECHANISM FOR STEREOTYPE PLATE CASTING MACHINES Filed July 16, 1949 7 Sheets-Sheet 6 INVENTOR 5 /5/0o/? TORNBEEG and 1904 .4. ran/501v Y M5 72%;, ZZQM, 71% WWW ATTO R N EYS Dec. 2, 1952 l. TORNBERG ETAL 2,619,694

PUMP OPERATING AND CONTROL MECHANISM FOR STEREOTYPE PLATE CASTING MACHINES Filed July 16. 1949 7 Sheets-Sheet 7 JW/TCH n41 VE ATTORNEYS Patented Dec. 2, 1952 PUMP OPERATING AND CONTROL MECH- ANISM FOR STEREOTYPE PLATE CAST- IN G MACHINE S Isidor Tornberg, Plainfield, and Paul L. Tollison,

North Plainfield, N. J assignors to Wood Newspaper Machinery Corporation, Plainfield, N. J

a corporation of Virginia Application July 16, 1949, Serial No. 105,202

8 Claims.

"This inventionrelatesto stereotype plate casting machines, and more particularly concerns mechanism for pumping type metal into the mold space of a plate casting machine under control 'of the mold space forming mechanism.

Stereotype plates for printing are cast from type metal in plate casting machines. These comprise essentially a mold space formed between relatively movable parts comprising a concave casting box and a cylindrically surfaced core, a mat or matrix carrying the type impression being secured to the interior of the casting box and the metal being pumped into the mold space from the melting pot. In all but the largest installations the mold space is opened and closed and the metal is pumped by hand. Such manually operable machines are sometimes operated in improper sequence with consequent hazards of injury to operating personnel, damage to the machines and loss of operating time. For example, the pump may be operated with the mold space open, spilling molten type metal on the floor near the machine. Also, the pump may be operated a second time before removal of a previously cast plate from the mold space, with the result that the molten type metal overflows the mold and spills over the machine and to the door. In many modern casting boxes, the matrix is held against the concave box surface by a vacuum applied through small holes in the concave 1 surface of the box. If the operator pumps metal into the mold space with no matrix in the casting box, the molten metal is drawn into the vacuum holes and the machine is thus put out of operation until costly and time-consuming repairs have been made.

The present invention has for its object the provision of power operated metal pumping mechanism for stereotype plate casting machines incorporating devices which insure that the mold space is in proper condition to receive the molten type metal when the pump is operated. To this end, the mechanism of the invention provides controls which permit operation of the pump to deliver metal to the mold space only after the casting box and core are in closed relation to form the mold space and then only if a matrix is in place in the casting box. The mechanism of the invention also provides means for prevent ing a second mold charging operation of the pump until after the mold has been opened for the removal of the cast plate and thereafter reclosed.

In describing the invention in detail, reference will be made to the accompanying drawings, in

2 which certain embodiments of the invention have been illustrated.

In the drawings:

Fig. 1 is a plan view of mechanism incorporating the invention applied to a plate casting machine of the type employing a rotary cylindrical core and a laterally movable casting box;

Fig. 2 is anelevation of the mechanism shown in Fig. 1;

Fig. 3 is a sectional view taken along the line 3-3 of Fig. 1 and showing the type metal pot and pump in section;

Fig. 4.is a plan view of the mechanism taken along the line 44 of Fig. 3;

Fig. 5 is a sectional View of the air control valve taken along the line 5-5 of Fig. 4;

Figs. 6, 7 and 8 are elevations of the air control valve and its control mechanism taken along the line 8-5 of Fig. 4 and respectively showing the mechanism in the position occupied when permitting operation of the valve (Fig. 6) in the position occupied when the valve is operated to effect a mold charging stroke of the metal pump (Fig. 7) and in the position occupied whenthe valve is locked against operation;

Fig. 9 is a plan view of the casting box and core, partly in section, showing the vacuum control mechanism responsive to the presence or absence of a matrix in the casting box;

Fig. 10 is a diagrammatic representation of the pneumatic and electric connections of the pumping control mechanism;

Fig. 11 is an elevation illustrating a modified form of mechanism embodying the invention and applied to a plate casting machine of the type employing a semi-cylindrical core that moves to a substantially horizontal position to discharge a cast plate; 7

Fig. 12 is a plan view of the pump operating valve control mechanism'of theembodiment of Fig. 11 taken along the line l2-l-2 of Fig. 11, the mechanism being shown in the position it occupies when the mold space is open and pump operation is prevented;

Fig. 13 is a plan view similar toFig. 12 showing the mechanism in the position it occupies when the mold spaceis closed and pump operation-is permitted;

Fig. 14 is an elevation, partly in section, taken along the line I i-l4 of Fig. 13 and showing the air and vacuum control mechanism; and

Fig. 15 is a diagrammatic representation of the pneumatic and electrical connections of the modification of the invention illustrated in Figs. 11-14.

Referring to Figs. l-4, inclusive, the plate casting mechanism includes a core I and a casting box 2, both disposed vertically of a suitable base 3. The core I is cylindrical and is rotatable about the axis of a central shaft 3 by a motor 4 through a shaft 5, a pinion 6 and a crown gear I. A clutch comprising a movable collar 8 splined to the shaft and engageable with a toothed member 3' fixed to the motor shaft controls the application of rotating power to the core. A pot 9 containing molten type metal I!) is located in a furnace adjacent the mold-forming mechanism and a pump l2 of conventional construction is supported by a bracket 6 in a position below the metal sur face in the pot. The pump I2 is provided with the usual piston I3, piston rod I4 and valve mechanism I5. A pump lever l6, pivotally supported by a stud I7, is connected to the piston rod M by links I8. A counterbalance I9 is carried by an extension of the pump lever I6, and a removable handle 20 may be provided to permit manual operation of the pump in emergencies. unit in the form of an air cylinder 2| to provide power for operating the pump is pivotally connected to an upstanding extension 22 of the bracket 5, and the piston rod 23 of this cylinder is pivotally connected to the pump lever I6, as shown. The construction of the air cylinder 2| is such that when compressed air is supplied to the upper end through the hose 24, the piston rod 23 is extended and the pump lever I6 is moved downward to perform a mold charging strokegof the pump I2, the magnitude of which stroke is adjustably limited by a stop screw 25. When compressed air is admitted to the lower end of the cylinder through the hose 23, the piston rod 23 is retracted, lifting the pump lever I6 and lowering the pump piston I3 in readiness for a subsequent mold charging stroke.

The mold space 21 in which the stereotype plates are cast is formed by the core I and the casting box 2 when in juxtaposition, as shown in Fig. 4, and this space is closed at its sides by matrix clips 28 of conventional construction. The molten type metal is introduced into the mold space through a spout 29 connected to the pump l2, as shown in Figs. 3 and The mold space is opened to permit removal of a plate by moving the casting box 2 laterally away from the core I and this is accomplished by known mounting and moving means, shown in Figs. 1 and 2 and generally designated 30. When the mold space is opened, the core I is rotated through a half revolution to carry the cast plate to an exposed position, opposite th casting box, so that it can be removed from the core. This half revolution motion of the core is governed by clutch mechanism of known construction, which will now be described.

The movable collar 8 of the clutch is provided with a circumferential groove engaged by a roller 3| carried by a, lever 32 having a handle 33. The lever 32 is carried by a fixed pivot 34. An extension of the lever 32 beyond the pivot 34 carries a roller 36 engaging a cam track 35 on a disc 31 located just below and rotating with the core turning crown gear 1, which rotates the core I. Oppositely disposed notches 3B and 38' in the track 35 permit the lever 32 to move to a clutch disengaging position under the bias imposed by a suitable spring 39 when the roller 36 enters one of the notches 38 and 38. This mechanism stops rotation of the core I at the successive positions where plates are discharged therefrom.

The normal sequence of operation of the cast- A power.

ing machine thus far described is that after a plate is cast, the operator operates the mechanism so that the casting box 2 is retracted from the core I and the newly cast plate carried on the core. The operator then moves the clutch handle 33 and permits the motor 4 to rotate the core I through a half revolution, as explained above. The operator then moves the casting box 2 back into mold forming relation with the core I by means of the mechanism 30, thus pushing the newly cast plate 01? of the exposed side of the core, and the mold space is then in readiness for casting the next successive plate.

In view of this sequence of operation, the rotation of the core through a half revolution makes it certain that the cast plate has been removed irom the mold space.

Compressed air for operating the pump lever l6 by the air cylinder 2| is controlled by a valve V mounted on a stationary plate 40 carried by posts 4| secured to a, flange 42 on the fixed hub in which the core shaft 3 rotates. The journals 44 that carry the shaft 5 are also carried by the stationary plate 40. The valve V has a compressed air inlet port 45 connected to an air pipe 46, an outlet port connected to the hose 26 leading to the lower end of the air cylinder 2|,

an outlet port 48 connected to the hose 24 leading to the upper end of the air cylinder 2|, and exhaust ports 49 and 50 connected to the atmosphere. carried by a central rod 52 slides vertically in the valve chamber and connects the inlet port 45 to the outlet port 41 when lowered as shown in Fig. 5, and connects the inlet port 45 to the outlet port 48 when raised by depressing the pivoted Valve handle 53. A spring 54 surrounding the upper end of the rod 52 moves the spool 5| to the lowered position when the handle 53 is released. The outlet port 48 is connected to the exhaust port 49 when the spool 5| is lowered and the outlet port 41 is connected to the exhaust port 50 when the spool 5| is raised. Thus, by depressing the handle 53 and subsequently releasing it, compressed air is admitted or exhausted to move the pump lever 6 up for a mold charging stroke and then down for a return stroke.

In accordance with the invention, the operation of the valve handle 53 is governed by the operation of the core cylinder I and the casting box 2 in such a manner that two successive metal charges cannot be pumped into the mold space without an intervening cast plate removin operation. The mechanism illustrated for accomplishing this result is particularly illustrated in Figs. 2, 4, 5, 6, 7 and 8. Referring particularly to Fig. 6, a stop bar 54 is pivotally supported beneath the valve handle 53 and is biased by asp-ring 55 to move clockwise toward the vertical lever blocking position shown in Fig. 8. A pivoted latch bar 55 is biased clockwise by a spring 51 and its end 58 is engageable with a lug 59 on the stop bar 54, a second lug 50 on the stop bar limiting the clockwise movement of the latch bar, as shown in Fig. 6. A slidable pin 6| extends through the plate 4!] on which the valve V is carried and the upper end of the pin lies beneath a foot 62 on the stop bar 54. The lower end of the pin 5| rides on the upper surface of the web of the crown gear I that rotates the core I, and th pin is raised by either one of two diametrically opposite cams 63 and 33' carried on the crown gear web, as shown in Figs. 4, 5 and 6.

A vertically slidable valve spool 5|- Assuming-the parts .to be in the position :illustrated-in-Fig. :6, 'andtfurther that the mold space 21 is :closed and 'a matrix is-in place in the castingbox =2, when thevalve handle '53 is-depressed to .cause a metal pumping operation, the latch bar 56 is moved down out of contact with the stop-bar lug'59, and the stop-bar -'54 moves to the right in contact with the valve handle 53, as shown in Fig. 7. When the handle .53 is released and-raised, the stop bar 54 moves toa vertical position beneath the handle (Fig. 8) and so pre ventsa second operation of the handle with :resultant flooding of the mold with molten metal. After the stereotypedplate has solidified in the mold space, the casting 'box 2 is retracted and the core I rotated through a half revolution, as explained above. During-the course of this --core movement, one of the cams 63 or 03 lifts the pin -6I tilting the stop bar 54 out of the path of the valve handle 53 and-engaging the latch bar end :58 with the lug 59 to hold thestop bar 54 in its retracted position. Since rotation of the core necessarily designates removal of the cast plate from the mold space, the valve handle 53 is released for further operation only after the cast plate has been removed.

Referring to Figs. 9 and 10, the casting box 2 is provided with a plurality of holes 05 on its inner face, all communicating with a manifold 66 connected by a pipe 61 with a suction mechanism or source of vacuum 68. According to the invention, a cylinder 69 is connected to the pipe 57 and Ya spring biased piston "F0 in this cylinder is suitably connected to close the electrical contacts 'II whena vacuum is drawn inthe manifold 66, and to open these contacts when no vacuum .is so drawn. When a matrix 72 is in place .in the casting box 2, it .is drawn or seated against the inner surface of the box and closes the holes 05 so that a vacuum isdrawn in the ducts comprising the manifoldfiitpipe Bland cylinder 69, moving the piston to the right when (Fig. 4) The operating lever E5 of the switch It is engagedand moved'to aswitch .closing position by a bracket IE on the casting box .2 .as the box moves to itsmold spaceclosing position adjacent the core I. Thus the switch .74 is closed only when the casting box .is in closed relation to the core.

Referring to Fig. 10, control current from a source designated A.-C. is connected in acircuit including the wire 1?, the limit switch '54, the wire 78, the vacuum contacts I I, the wire I9 and the solenoid of a solenoid valve 8.0 in the air supply pipe 46. The solenoid valveSfl is of known construction and opens when energizedso as to admit compressed air through the pipe 09 leading'to the inlet port of the control valve V. With this arrangement, the metal pump I2 can be operated to perform a mold charging stroke only if a matrix is in the casting box and-the casting box is in closed relation to the core and then onlyif the last previously cast plate has been removed from the mold space by turning the core through a half revolution.

A modified form of apparatus for carrying out the invention is illustrated in Figs. 11-15. This modification is applied to a known form of plate casting. apparatus employing a semi-cylindrical core 181i 'carriejdbyrollers 82 running :on tracks 83, the core 01 being linked to the frame 84 :by pivoted links 85 so that the core may be moved from a vertically closed position adjacent the stationary casting box '86 to a horizontal open position in which the cast plate 01 is discharged. Thecore SI is shown in broken lines in the closed position and in full .lines in the open position in Fig. 11. A foot pedal 8.8 may be provided to start the core -8I away fromthe casting box 86 after a plate has been cast and the usualhandle 88' isprovided for tilting and returning the core.

The melting pot 89 is'disposed in a furnace-90 and is provided with a single stroke pump .9I

connected to deliver molten type metal to the mold space between the casting box '86 and the core BI through a spout 02. The pump .9I is operated by a counterweighted pump lever-93 linked to the pump piston rod 04 and pivoted to a bracket 95. An air cylinder 96, pivotally supported at its lower end in a bracket '91, has a piston rod 08 pivotally connected to :the pump lever 90, as shown. A tube 99 surrounds the piston rod 98 and'its upper end acts as a stop for engagement by a nut I00 threadedly engaging the rod 08 and adjustably threaded to fix the magnitude of themetal chargingstroke. Air hoses IOI and I02 lead, respectively, to the lower and upperends of the air cylinder 96 from the control valve V. The valve V" is of the same construction as the valve V, described above. It

' acts to supply compressed air'from the air supply pipe I03 tothe hose HM and so to operate the pump 9I through a metal chargingstroke when'the valve handle I00 is moved forwardly, asshown in Fig. 11, and to supply compressed air to'the hose I02 and so operate the pump through its return'stroke when the handle I04.is returned to a :rearward position when released.

Referring to Figs. '12, 13 and 14, the valve V and its control mechanism are mounted on abracket I05 secured to the machine frame 84. Aslide I06 carrying-a'rod I0'I is slidably mounted in the bracket I05. An adjustable screw I08 extends fromtheend of the rod I01 and is locked in adjusted position by a nut IIO. A spring Hl connected between the slide I06 and'th'e bracket I05 biases the slide and the rod I01 to move to the left to the'position shown in Figs. 11 and 12.

A stop bar I'I2 'is-pivotally mounted onthe-bracket' I05 and is biased by a spring II3, to move counterclockwiseagainst a stoppin I I4, in-which position the bar I'I2 prevents pump operating movement of the valve handle I04 (Fig. 12). A latch bar H5 is pivotally mounted on the slide I06 and is biased by a spring 'I I6 to turn counter clockwise toward a position engaging a stop pin II'I. When in this position, the free end-of the latch bar H5 is in line with a pin H8 on the stop bar H2 so that movement of the slide I06 to the right moves the stop bar II2 to the right and out of the path of the valve handle I00, as shown in Fig. 13. A hub IE9 on an arm I20 connected to the core-SI carriesthe'shaft of the roller 82 and is aligned'with the end of thescrew IIO. When the core 8! ismoved to its vertical or closed position adjacent the casting box 86, the hub II9 engages the screw I08 and moves the rod I01 and slide I06 to the right against the bias of the spring III to the position shown in Fig. 13. During this movement, the latch bar H5 moves the stop bar IIZ to the right out of the path of the valve handle I04, and this handle canthereafter be pulled forward to cause 7 a metal charging stroke of the pump 9|. This forward movement of the handle I04 moves the latch bar H5 out of the path of the pin H8 and the spring H3 returns the stop bar II2 to a position in which it engages the side of the handle I04. Then, as the handle I04 is returned to its rearward position to cause the return stroke of the pump 9|, the stop bar II2 snaps under the lever I04 and prevents its subsequent movement to cause a second metal charging stroke of the pump. When the core 8| is tilted to discharge the cast plate 81, and thereafter returned to closed position, the latch bar II5 again moves the stop bar II2 out of the path of the valve handle I04 and so sets the mechanism in condition for a subsequent metal charging stroke of the pump 9I.

The casting box 86 of the apparatus shown in Fig. 11 is provided with a vacuum manifold and holes for drawing the matrix against the concave casting box surface, as has been explained above in connection with Fig. 9. The pipe I2I connecting the source of vacuum I22 with the casting box 86 is also connected with a cylinder I23 carrying a spring biased piston I24 that closes the electrical contacts I25 when the presence of a matrix in the casting box builds up a vacuum in the pipe I2I, the contacts I25 being open if no matrix is present.

When the handle I04 of the valve V is moved to the charging stroke position, if there is a matrix in the casting box 86, the contacts I25 are closed and the solenoid valve I26 is energized through the circuit shown in Fig. 15, admitting compressed air to the inlet of the valve V through the pipe I27. The compressed air passes through the hose IOI to the lower end of the air cylinder 96, lifts the plunger 98 and so causes a charging stroke of the pump 9I. Release of the valve handle I04 permits return of the valve to the return stroke position in which compressed air is delivered through the hose I02 to the upper end of the air cylinder 96, lowering the piston rod 98 and returning the pump to a position in readiness for another charging stroke. A second operation of the valve handle I04 is prevented by the stop bar II2 until after the core 8I has been opened for removal of the casting plate therefrom. Since the stop bar H2 is moved out of the path of the valve handle I04 only when the core 8I is closed against the casting box, the metal charging stroke cannot take place until the mold space is closed.

From the foregoing description, it will be apparent that the invention provides mechanism for the safe power operation of the molten type metal pump, the mechanism being such as to prevent the pumping of metalwith the mold space open or with a charge of metal'or a cast plate in the mold space. Where a vacuum is employed to hold the matrix against the concave casting box wall, the mechanism of the invention also prevents the pumping of metal into the mold space unless the matrix is in position. It will be understood that in plate casting machines lacking this vacuum feature, the vacuum responsive control described will be omitted without change in the structure or functions of the other abovedescribed safety mechanisms.

We claim:

1. In a stereotype plate casting machine of the type including relatively movable mold forming members having surfaces forming a mold space therebetween upon movement of one of said members toward the other, a metal pump for delivering molten metal .to said mold space, a source of suction and ducts connecting said source to the mold forming surface of one of said mold forming members for seating on said surface a matrix placed over the mouths of said ducts, a power unit for operating said pump, and a conduit for supplying operating energy to said power unit, the improvement which comprises the comloination therewith of a valve in said conduit normally closed to prevent the flow of energy to said power unit, and a pressure responsive device connected to said mold member ducts and responsive to a drop in pressure therein resulting from the closing of the mouths of said ducts by a matrix seated on the mold forming surface of said member for opening said valve.

2. In a stereotype plate casting machine of the type including mold forming members having surfaces relatively movable to discharge a cast plate from and reform a mold space therebetween, a pump for delivering molten metal to such mold space, a source of suction and ducts connecting said source to the mold forming surface of one of said mold members to seat on such surface a matrix placed over the mouths of said ducts, a power unit for operating said pump through a metal charging stroke and a return stroke, a conduit for conducting operating energy to said power unit, and a control device connected in said conduit and including a handle movable to a charging position to energize the power unit to perform a metal charging pump stroke and to a return position to perform a return pump stroke, the improvement which comprises the combination therewith of a bar movably mounted adjacent said handle and movable into and out of a position blockin the path of movement of said handle to the charging position, means biasing said bar to move to said blocking position, a

movable element adapted upon movement to move said bar out of said blocking position, said movable element being disposed in the path of and adapted to be moved by mold reforming movement of one of said relatively movable mold forming members, a valve in said conduit normally closed to prevent the flow of energy to said power unit, and a pressure responsive device connected to said mold member ducts and responsive to a drop in pressure therein resulting from the closing of said ducts by a matrix placed over the mouths of said ducts for opening said valve. 3. In a stereotype plate casting machine the improvement as set forth in claim 2 which includes latch means for engaging and holding said, bar out of blocking position and movable when, said handle is moved to the charging position for releasing said bar for return by said biasing means to its handle blocking position when said handle moves to its return position.

4. In a stereotype plate casting machine of the type including a concave semi-cylindrical casting box, a cylindrical core adjacent said casting box and rotatable to remove a cast plate from the mold space therebetween, a metal pump for delivering molten metal to such mold space, a power unit for operating the pump through a mold charging stroke and a return stroke, a conduit for conducting operating energy to said power unit, and a manually operable control device in said conduit having a handle movable to a charging position in which operating energy from said conduit operates said power unit to cause a charging pump stroke and to a return position in which operating energy from said conduit opcrates said unit to cause a return pump stroke,

the improvement which comprises the combination therewith. of a bar movably mounted ad- J'acent said handle and movable into and out of a position blocking charging movement of said handle, means biasing said bar to move to said blocking position, and a movable latch lying in the path of movement of said handle to its charging position and engageable by said handle and engageable with said bar to hold said bar out of said blocking position until said latch is engaged and displaced by movement of said handle to its charging position.

5. In a stereotype plate casting machine of the type including mold forming members relatively movable to discharge a cast plate from and reform a mold space therebetween, a metal pump for delivering molten metal to such a mold space, a power unit for operating the pump through a metal charging stroke and a return stroke, and a control device for controlling the energization of said power unit and including a handle movable to a charging position in which the power unit is energized to perform a metal charging pump stroke and to a return position in which said power unit is energized to perform a return pump stroke, the improvement which comprises the combination therewith of a bar adjacent said handle movable into and out of a position blocking the path of movement of said control device handle to the charging position, means biasing said bar to move to said blocking position, latch means adapted to engage and hold said blocking bar out of blocking position after each mold reforming movement of one of said relatively movable mold forming members, said latch means being engageable and movable by said handle when said handle is moved to the charging position for releasing said bar for return by said bar biasing means to its handle blocking position when said handle moves to its return position, and means biasing said latch means toward its blocking bar holding position,

6. In a stereotype plate casting machine the improvement set forth in claim in which said blocking bar is pivotally mounted and in which the latch means is a pivotally mounted latch lying in the path of movement of said handle to the charging position when so holding the bar out of blocking position.

7. In a stereotype plate casting machine of the type including a rotary cylindrical core, a concave cylindrical casting box adjacent said core and movable toward and away from said core to close and open a mold space therebetween, and means for rotating said core to remove a cast plate from the mold space, the improvement as set forth in claim 5 which includes a pin mounted adjacent said blocking bar and movable into engagement with said blocking bar to move said bar out of its handle blocking position, and means carried by said rotary cylindrical core and engageable with said pin upon plate-removing rotation of said core to move said pin into engagement with said blocking bar to move said blocking bar out of handle blocking position.

8. In a, stereotype plate casting machine of the type including a casting box and a core movable toward said casting box to form a mold space and movable away from said casting box to re move a cast plate from said mold space, the improvement as set forth in claim 5 which includes a slide mounted adjacent said handle and movable by said core when said core is moved toward said casting box to form a mold space, said latch means being mounted on and carried by said slide.

ISIDOR. TORNBERG. PAUL L. TOLLISON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 699,466 McRae et al Mar. 5, 1901 1,160,973 Clark Nov. 16, 1915 1,279,650 Bungay Sept. 24, 1918 1,398,314 Bungay Nov. 29, 1921 1,514,103 Rogers Nov. 4, 1924 1,599,624 Stern Sept. 14, 1926 1,662,750 Kaufmann Mar. 13, 1928 1,689,698 Tornberg Oct. 30, 1928 1,787,462 Wood Jan. 6, 1931 1,810,867 Wood June 16, 1931 1,856,430 Roesen May 3, 1932 1,900,265 Wood Mar. 7, 1933 1,927,384 Bauer Sept, 19, 1933 1,981,380 Wagner Nov. 20, 1934 1,981,381 Wagner Nov. 20, 1934 2,108,080 Schultz et a1 Feb. 15, 1938 2,145,956 Stern Feb. 7, 1939 2,173,990 Wood et a1 Sept. 26, 1939 2,243,835 Brunner et a1 Jan. 3, 1941 2,449,280 Coulthard Sept. 14, 1948 2,470,146 Crafts May 17, 1949 2,515,231 Kalina July 18, 1950

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