US3063548A - Metal pot mouthpiece for typographical linecasting machines - Google Patents

Description

Nov. 13, 1962 E. MIDGETTE ETAL 3,063,548

METAL POT MOUTHPIECE FOR TYPOGRAPHICAL LINECASTING MACHINES Filed April 25, 1960 INVENTORS ERNST L.MIDGETTE EMANU SARFATY BY JOHN BITTNER AGENT United States Patent 3,063,548 hiETAL PDT MOUTl-IPIECE FOR TYPOGRAPHICAL LINECASTING MACHINES Ernst L. Midgette and Emanuel Sarfaty, Brooklyn, and

John W. Bittner, Rhinebeck, N .Y., assignors to Harris- Intertype Corporation, Brooklyn, N.Y., a corporation of Delaware Filed Apr. 25, 1960, Ser. No. 24,542 2 Claims. (Cl. 199-47) This invention relates to improvements in mouthpieces for slug casting machines of the general class disclosed in US. Patent No. 436,532 granted September 16, 1890, wherein composed lines of character bearing matrices are presented edgewise against one face of a slotted mold and the mouthpiece on the metal pot is brought against the opposite open end of the mold after which molten type metal is pumped through orifices or jets in the mouthpiece into the mold cavity and against the intaglio characters in the matrices to form a type bar or slug having cameo characters on one edge thereof.

Because the maximum level of the metal in the pot reservoir must always be maintained somewhat below the jets in the mouthpiece in order to avoid spilling of the molten metal as the pot rocks to and from the casting position, it follows that there is always a volume of air in the throat of the pot above the normal metal level therein, even when the mouthpiece is advanced and engaged with the mold prior to the casting operation. Accordingly, the most important factor, in casting solid close-grained slugs capable to withstand pressure in direct printing, is efiicient ventage of air from the mold each time a slug is cast. In the usual design of pot crucible mouthpiece, ventage of air is provided for by vertical cuts in the mouthpiece between the jets. These vents permit the head of air and a slight amount of type metal to escape as each cast occurs and in the normal process of operation, utilizing the most commonly used type metal which generally is composed of approximately 4% tin, 11.5% antimony and 84.5% lead, this type of vent usually supplies sufficient yentage of air.

However, when hard metal is used to form slugs from which it is desired to produce a very high number of impressions such as for telephone directories and catalogs, the above described style of vent is not efficient in that the hard metal, which is generally composed of approximately 14% tin, 24% antimony and 62% lead, must be used at a substantially higher temperature and the higher content of tin and antimony causes the metal to more readily adhere to the mouthpiece particularly in the vent slots. When the slots become filled with solidified metal they no longer function as vents thus causing larger air pockets in the slugs which are thereby substantially weakened to the point where they may break down under printing pressure.

According to the present invention, the vertical vents are eliminated and ventage is achieved by providing a horizontally disposed relief cut in the casting face of the mouthpiece from a point approximately through the center of the jets and extending downwardly through the lower lip of the original casting face. This relief cut is of a length which exceeds the width of the slug to be cast and, therefore, causes a more or less solid sprue to form during the casting operation. This sprue is readily trimmed by the back knife of the casting machine during rotation of the mold disk to ejection position at which the side trimming knives will remove any excess sprue. It has been found that, because of the brittle nature of hard metal, the sprue breaks off cleanly without curling.

Whereas the present invention is particularly adapted to the production of hard-metal slugs, it may be readily adapted to the production of standard line casting machine type metal slugs by varying the depth of the relief cut in accordance with the temperature at which the type metal must be maintained.

In view of the foregoing, it is the principal object of this invention to provide a greatly improved and more efiicient means of venting air from the mold of a slug casting machine.

Another object of this invention is to provide an improved design of mouthpiece venting which is substantially more economical to produce than present vertical vents.

A still further object of this invention is to provide a mouthpiece venting arrangement which is adapted to be more efiiciently cleaned by mouthpiece wiper action.

Other objects and structural details will be apparent from the following description when read in conjunction with the accompanying drawings wherein:

FIG. 1 is a front elevational view of the mouthpiece of the present invention.

FIG. 2 is an enlarged sectional view, taken on the line 22 of FIG. 1, showing the mouthpiece in casting relation to a mold and matrix.

FIG. 3 is a side elevational view of a metal pot of the type to which the present invention is adaptable.

Referringto FIG. 3, the mouthpiece 4 of the present invention is shown as applied to a metal pot 6 of the usual form employed in matrix composing and linecasting machines of the class hereinbefore referred to. 'Such pots are generally surrounded by electrical heating elements or gas heating equipment is provided which retains the type metal 8 in a fluid state in which it may be forced through the crucible throat 10, by actuation of a plunger 12, through jets 14, in mouthpiece 4, into mold cavity 16 and against the intaglio characters of matrices 18 to form a type bar.

Referring to FIG. 2, the slotted mold is formed by a pair of well known mold liners clamped between a mold cap 20 and a mold body 22 which in turn is secured to a rotatable mold disk 24.

Referring to FIGS. 1 and 2, a venting recess 26 is provided in the casting surface 28 of mouthpiece 4. This recess is of such length as to exceed the length of a line of matrices from which a slug is to be cast and the upper edge of said recess is disposed horizontally and through the approximate centers of jets 14 and of such depth that a negligible quantity of excess metal will be permitted to flow between the face of the recess and the adjacent mold during a casting operation. Referring to FIG. 2, the depth of venting recess 26 is exaggerated for purposes of illustration; whereas, it has been found that a depth of approximately .002 inch is ideal when hard metal of the specification set forth hereinabove is used and a pot crucible temperature of 645 -650 F. is maintained.

Operation When a line of matrices 18 is presented to one side of the slotted mold 16 of the typographical linecasting machine and the metal pot 6 and mouthpiece 4 of the present invention is brought into contact with the other side of the mold, plunger 12 is actuated by well known means (not shown) and forces molten metal through throat 10 and jets 14 of the mouthpiece into the mold cavity and against the characters on the matrices. As the metal is forced into the mouthpiece and through the jets thereof the head of air above the normal metal level in the throat is forced through the jets ahead of the metal and is eX- pelled through vent passage 26 as is a small amount of excess type metal.

After the cast is completed and the metal pot breaks away from the mold in the mold disk a metal pot mouthpiece wiper (not shown) such as disclosed in expired U.S.

Patent No. 1,654,488 is caused to make a stroke across the mouthpiece thus removing any type metal which might have adhered thereto. The efficieney of the mouthpiece wiper in combination with the mouthpiece of the present invention is much greater than when used with conventional vertical vents in that the vent of the present invention is an unobstructed single horizontally disposed passage.

According to the present invention, the sprue which forms in the vent 26 and overflows slightly therefrom will be solid throughout the length of the slug. As the mold disk is rotated to ejection position, the back knife will trim the back of the slug to an accurate type high dimension and any overhanging material on the thickness dimension Will be trimmed cleanly at ejection. It has been found that these trimming operations are exceptionally clean because of the brittle nature of hard metal and its consequent resistance to curling during the trimming operations.

While we have described what we consider to be a L highly desirable embodiment of our invention, it is obvious that changes in form can be made without departing from the spirit of our invention, and we, therefore, do not limit ourselves to any thing less than the whole of our invention as hereinafter claimed. What we claim is:

1. In a typographical linecasting machine a molten metal pot, a mouthpiece attached to said metal pot and having a casting face, a plurality of orifices through said casting face and in communication with molten metal in said pot, a slotted mold, including a cap and a body portion, aligned with said orifices, a line of character bearing matrices adapted to close one opening of said mold while said casting face abuts the other opening of said mold, a single elongated transversely extending vent recess in the casting face of said mouthpiece extending from a point in communication with said orifices downwardly and clear of said mold.

2. A mouthpiece for a typographical lineca-sting machine, having a casting face, a plurality of orifices through said face for the passage of molten type metal and a single elongated transversely extending vent recess in said casting face and in direct communication with said plurality of orifices, said vent recess being of a length at least equal to that of the line of type to be cast.

References Cited in the file of this patent UNITED STATES PATENTS 1,458,659 Letsch June 12, 1923 2,150,339 Rabinowitz Mar. 14, 1939 2,247,996 Grifiith July 1, 1941 2,560,503 Christman et al July 10, 1951

Images