US2016283A - Mold for casting stereotype printing plates - Google Patents

Description

'0. 8, 1935. w HUCK MOLD FOR CASTING STEREOTYPE PRINTING PLATES 2 Sheets$heet 1 Filed June 2, 1932 INVENTOR @QMVZ/ZQ njzuzk Kid;

Oct. 8, 1935.

w. HUCK MOLD FOR CASTING STEREOTYPE PRINTING PLATES Filed June 2, 1952 2 Sheets-Sheet 2 IQ am F I P .l

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INVENTOR Patented Oct. 8, 1935 UNITED STATES PATENT OFFIC'E MOLD FOR CASTING STEREOTYPE, PRINTING PLATES ration of New York Application June 2, 1932, Serial No. 614,910

.10 Claims.

This invention relates in general to molds for casting stereotype printing plates, and has for its object, the provision of certain improvements that will obviate the tendency of stereotype 5 plates that are cast in molds of conventional type to become deformed when removed from the mold.

Another object is to provide a novel method and means for equalizing the absorption of heat 10 from stereotype plates during the casting operation.

Another object is to provide a stereotype plate casting mold of a design and construction particularly adapted to produce printing plates comparatively free from internal stresses resulting in deformation and a tendency of the finished plate to become warped and develop cracks after removal from the machine.

A further object is the provision of an improved casting box or chamber for a stereotype plate casting machine that will insure the production or casting of printing plates of uniform characteristics and homogeneous structure.

A still further object is to provide means for delaying the cooling of selected areas of a stereotype plate during the casting operation in order to assure the production of printing plates free from defects in structure or configuration.

Other objects and advantages will be found in the details hereinafter set forth.

As is well known to those skilled in the printing art, one of the chief diificulties encountered in the casting of printing plates has hen the marked tendency towards deformation of a certain percentage of printing plates when taken from the casting chamber or box. This being due to the uneven solidification of the molten streotype metal in the mold whereby internal stresses and strains are develop Fd in their printing plates arising from the unequal cooling of the opposite sides of the said plate or the unequal absorption of heat from the printing plate while still in the mold, by the opposite sides of the casting chamber.

The matrix which lines one side of the casting chamber during the casting process is of a composition having poor heat conducting properties, consequently the molten metal engaged against said matrix will cool more slowly than the molten 50 metal that is in contact with the opposite and bare wall of the casting chamber, where it cools rapidly. The difference in cooling produces or sets up stresses in the exterior of the plate, which will in many cases cause the said plate when taken from the casting chamber to warp or to develop fissures and cracks, and in curved plates there is also a tendency for the curved edges to straighten The matrix side of the plate by the cooling process above indicated is subjected to tensional stresses, which is opposed by compressional stresses in the opposite side of the plate. Upon removal of the curved plate from the mold, these force couples will cause it to cave-in along its straight edge and open up in its curvature. In particular, the edges or margins of stereotype plates have been found to cool more rapidly than the body portion resulting in a tendency to deformation in the finished plate which in the case of a curved plate frequently produces a saddle formation and opening up of same.

In accordance with the present invention, and as forming an important feature thereof, a stereotype plate casting device is provided having a novel mold or casting chamber particularly adapted to prevent unequal cooling of ,the opposite sides of a printing plate.

The invention will be best understood when taken in connection with the accompanying drawings in which Figure 1 is a side elevational view, partly in section of a stereotype plate casting machine embodying the invention;

Figure 2 is a front elevational View as seen in the direction of the arrow 2 of Figure 1;

Figure 3 is a vertical sectional view of the device, with parts broken away, showing the arrangement and disposition of parts to operatively accommodate electric heating means for retarding or controlling the cooling of the core side of the mold in accordance with the invention;

Figure 4 is a transverse sectional View taken on line 44 of Figure 3;

Figure 5 is an elevational View of the device; Figure 6 is a sectional view taken on the line and as seen in the direction of the arrow 6 of Figure 3;

Figure '7 is a transverse sectional view taken on line !1 of Figure 5; and

Figure 8 is a fragmentary elevational view, with parts broken away, of the heating or temperature controlling coil and its casing.

The invention is embodied in a plate casting device A, which comprises a base 8, to which are fastened side frames 9 and the vertically positioned core or fixed member 10 of the casting mold or box.

Upon the side frames 9, the body portion or movable mold member ll of the casting mold is adjustably positioned so that same may be swung from the horizontal position, shown in 'II of the casting mold may be manipulated or moved by the handles 18, and since the trunnions I2, I3 and tracks i6, I! are arranged and located to support the said body portion II of the mold in balanced condition at all angles or positions, it will be understood that same may be handled with comparative ease and without undue strain.

or effect on the part of the operator. The cooling of the core member Ill is provided by a water jacket or chamber I9 which may have a valve controlled inlet pipe 28 and an outlet pipe 20'.

In accordance with the present invention and for the purpose of preventing too rapid a cooling of the edges or margins of a stereotype plate, the member Iii is formed or provided with a recess or pocket H in which'heat insulating material 22 is secured. When desired, means for heating the portions of the mold adjacent the recess 2| may be. provided as hereinafter described. In addition'to the insulating material 22, a sheet or web of insulation 25 that may be paper or other suitable material for the purpose of preventing too rapid a cooling of one side or face' of the body portion of the stereotype plate, may be secured to or wound on spindles or bars 24, 25 having squared upper ends 24, 25', the said spindles being rotatably secured to the frame or support of the core member IE3 and mounted in sockets as at 2,6 fastened thereto. Suitable means for locking the spindles 24, 25 to hold the sheet material 23 securely in the casting chamber are provided, which may be pawl-engaged gears 21, 28 on the respective spindles 24, 25.

When the rods on which the paper insulation 23 is engaged or wound, is turned, the said paper, which is preferably of heavy stock, will be drawn tightly against the core wall formed by the fixed member Ill, the coacting opposite or matrix wall being formed. by the movable or swingable mold member II, which is lined by the matrix C. In order to clamp the sheet of paper 23 the use of which latter is optional, a pair of clamping members is employed, each consisting of a band or strap 25, the ends ai 32 of which are secured by screws 33 to bars or shafts 3i, in which adjusting screws 35, 3,6 are mounted.

Each of the adjusting screws 35, 36 has one end engaged in a pocket or recess formed in the fixed mold member. As the screws 35, 36 are turned, the adjacent bar 34 will be moved towards or from the fixed member I6 and the strip 29 engaged against the sheet of paper 23, or released therefrom. The sheet of paper augments the action of the inserted section of insulation in preventing a too rapid absorption of heat from the cooling plate by the wall of the core II] of the casting box opposite the wall against which the matrix C is pressed.

The casting chamber or box formed by the coaction of the fixed and movable members I0 and I I is closed at the bottom by the usual head in the movable mold member I I.

to a shaft 42 having secured thereto a crank arm 43 hinged to one end of a link 44 the other end of which is similarly connected to a second crank arm 55 which is secured to a shaft 46. The shaft 2 has a pair of locking members 41, 48 secured 5 thereon, each of said locking members being provided with a slot 49 which is adapted to receive a pin (not shown) fastened in the movable portion of the machine. The shaft 46 is also provided with similarly formed locking members 5|, 1o 52 which coact with pins or members (not shown) When the handle M is manipulated the locking members 41, 48,

5! and-52 will be simultaneously moved to lock the body portion or movable mold member II 15 to the core member ID or to release same when desired in accordance with well known practice. A head gauge 38 is provided which may have operating handles 53. For the purpose of retaining the movable mold member in the 20 horizontal position shown in dotted lines in Figure 1, a suitable retaining device, hinged to the frame Q and indicated generally at 54 is also provided.

As a feature of the present invention, a U- shaped recess, best shown in Figure 5, is arranged 25 adjacent the side edges and bottom of the fixed mold or core member ID, and not elsewhere. Within a groove 64 provided in the recess 2|, a U-shaped heater unit 65 having a resistance coil 68 is inserted. The ends of the resistance coil 65 30 are connected to binding posts 61, 68, to which latter electric conductors 69, ll supported in brackets 12, 13, are attached. a

In operation and in accordance with the invention as described above, the casting chamber is 35 prepared by securing a matrix C to the body portion or movable mold member I I as hereinbefore described. Molten metal may now be poured into the open top of the mold to form a stereotype plate 40. The paper 23 will tend to prevent a too 4,0

rapid chilling of the body portion of the printing plate, while the insulating material 22 secured in the recess 2I and the resistance coil heater unit 65 (in the recess 64), which meanwhile, it will be understood, has been energized from the 45 conductors 69', 'H,will combine to prevent a too rapid cooling of the edges of the cast printing plate, where the major stresses due to uneven cooling are apt to take place while it is still in the casting box, for reason pointed out above. The 50 cooling of the plate at the edges and on both sides of the body portion will now be approximately uniform, and as a consequence, the said plate will be freed from stresses and strains tending to warp or distort same. 55 It will be understood that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, andit is therefore desired that the present embodiment be considered in all respects'as Q0 illustrative and not restrictive, reference being bad to the claims rather than to the foregoing description to indicate the scope of the invention.

VZhat I claim is:

1. In a mold for casting curved stereotype member which coact to form a casting chamber, 5 V

means for securing a matrix to the first mold member, a recess formed in the second mold member and extending along its bottom edge and along its side edges but not elsewhere, and heating means in the recess.

3. In a mold for casting curved stereotype printing plates, a concave mold member and a coaeting convex mold member, means for securing a matrix to the concave mold member, a recess extending along the bottom edge and side edges of one of said mold members but not elsewhere, and electrically-actuated means in the recess for equalizing on all sides the cooling of a plate forming within said mold.

4. A mold for casting printing plates comprising a fixed member and a member movably secured thereto, said fixed member having a wall provided with electrically actuated heating means arranged on the side and bottom edges thereof alone, said movable member having a wall adapted to engage a matrix applied thereto, whereby molten metal poured into a casting chamber formed by thewalls of the fixed and movable members will form a plate comparatively free from deformation due to unequal absorbtion of heat while cooling.

5. In a device for casting printing plates, a movable member having a matrix-receiving inner wall, and a fixed member, said fixed member having a wall recessed at the side and bottom edges but not at any other portions to receive recess therein, and means connected to the fixed member for adjusting the sheet of insulating a web of paper juxtaposed against said fixed member, electrically operated heating means arranged in the side edges and bottom edge of said fixed member but not in other portions thereof, and rotatable means including a pair oi cylindrical members for moving said web of paper in order to present fresh surfaces thereof between said inner wall and said fixed member.

8. In a device for casting printing plates, a movable member having a matrix receiving inner wall, a fixed member arranged adjacent said movable member, electrically operated heating means secured to the side edges and the bottom edge of the fixed member but not to other portios thereof, and means for moving sheet material between the inner wall and the fixed member, said means including revolvable cylindrical members, said cylindrical members being lockable in predetermined positions.

9. A printing plate casting device of the kind described including a concave mold member and a convex mold member forming a casting chamber therebetween, and heating means secured to the bottom and side edges alone of the convex mold member whereby absorption of heat from the edges of a plate forming in said casting chamber is retarded.

1s. A printing plate casting device of the kind described including a concave mold member adapted to support a matrix, and a convex mold member having heating means secured to the bottom and side edges alone thereof whereby absorption of heat from the edges of a plate within said device is retarded.

WILLIAM F. HUCK.

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