US3156959A - Linecasting machines - Google Patents

Description

1964 P. HILPMAN ETAL 3,156,959

LINECASTING MACHINES Filed Sept. 4, 1959- INVENTOR. PAUL HILPMAN y LEROY/ ALBERT 4WMM ATTORNEY United States Patent 3,156,959 LINECASTING MACHINES Paul Hiipman, Garden ity, and Leroy F. Albert, Brooklyn, N.Y., assignors to Eltra Corporation, a corporation of New York Filed Sept. 4, 195a, Ser. No. 838,095 2 Claims. (Cl. 22-71) This invention relates to improvements in metal pots for slug casting machines and more particularly to those of the general class disclosed in United States Patent No. 436,532, wherein lines of character bearing matrices are presented to one face of a slotted mold and an elongated mouthpiece on the metal pot is brought against the opposite face of the mold to cast a type slug therein, the metal pot usually having a pump therein which is operative at the appropriate time to inject a charge of molten metal from the metal reservoir through the metal pot throat and through orifices in the mouthpiece and into the mold, after which the metal pot retreats and the slug is ejected from the mold.

In order to maintain the metal in the pot in molten condition and at the proper temperature to produce good type slugs, it is customary to provide heaters which are applied to the main metal reservoir of the pot, and since the mouthpiece is located at the outer end of the throat and remote from the pot reservoir, other heaters are usually provided to supply sufficient heat to the throat and mouthpiece to insure the proper flow of the molten metal therethrough.

It is well known, in the operation of slug casting machines, that the temperature of the metal pot mouthpiece is an important factor in the production of satisfactory type sings, and while it is the aim in practice to maintain the mouthpiece at a uniform temperature, it has been found that uniformity in the application of heat to the mouthpiece is not always desirable, and in any event, such uniform application of heat does not always maintain the uniform desired temperature at the mouthpiece. The reason for this is the additional amount of heat supplied to the mouthpiece due to the flow of molten metal through it in the course of casting slugs. Since the flow of metal is intermittent the heat supplied by the metal is likewise intermittently applied. This means that the tem perature of the mouthpiece is raised and lowered depending on the amount of metal passing therethrough and the frequency thereof. To compensate for this a temperature control is used to energize the mouthpiece heater when the temperature falls below a predetermined temperature and to deenergize the heater when the mouthpiece temperature rises to a prescribed level. Even so, the temperature cannot be maintained perfectly constant, but rather it rises and falls within certain narrow limits depending on the cycle of operations of the machine.

At the present time the mouthpiece heater is secured in place on the metal pot by a rigid clamping mechanism which securely holds the heater element in engagement with the mouthpiece. The arrangement has been such that with the rise and fall of the mouthpiece temperature as hereinabove referred to, the clamping mechanism becomes loose with the result that the heater element no longer is in engagement with the mouthpiece but is separated from it. The consequence of this is that an imperfect temperature control of the mouthpiece is obtained.

The object of the present invention is to obviate the difficulties encountered with prior heater element clamps and thereby obtain a better temperature control of the mouthpiece.

In carrying out the invention, there is provided a spring biased member which urges the heater element into engagement with the mouthpiece so that as the clamping apparatus expands and contracts with the rise and fall of the mouthpiece termperature the heater element, under the urging of the spring biased member, will always be in tight engagement with the mouthpiece. Moreover, the temperature sensing probe has been advantageously relocated so as to more accurately reflect the mouthpiece temperature and thereby maintain a better temperature control thereof as by keeping the range of temperatures within narrower limits than was heretofore possible.

Features and advantages of this invention will be gained from the foregoing and from the description of a preferred arrangement thereof which follows.

-In the drawings:

FIGURE 1 is a side elevation partly in section of a metal pot according to the present invention; and

FIGURE 2 is a sectional view taken along line'22 of FIGURE 1.

As shown, the casting mechanism comprises a metal pct 10 formed with a well 11 therein, and having a discharge spout 12 leading from the well and adapted to deliver molten metal into a mold 13. The ejection of the molten metal from the pot is effected by means of a plunger 14 movable down and up in the well 11 and operated by a plunger rod 15 pivotally connected thereto at its lower end by a pin. The plunger rod 15 extends upwardly through the bath of molten metal and it is pivotally connected at its upper end to the normal actuating mechanism (not shown) adapted to move the rod and the associated plunger down and up in successive casting operations. It is quite apparent that as the plunger 14 moves down and up in effecting the casting of a slug, the level of the molten metal in the discharge spout 12 rises to fill the mold 13 and then, as the plunger 14 is raised, falls to its normal level as shown. It is the intermittent passage of the molten metal through the mouthpiece which causes the mouthpiece temperature to fluctuate. This, of course, means that the temperature is dilficult to control particularly since, until the present invention, it was not even possible to keep the mouthpiece heater element in close contact with the mouthpiece.

The throat heater element 20 is held in place at its lower end by means of clamp bar holding screw 21 which is threaded through a clamp bar 22 and bears against the heater element 20. The clamp bar is provided with two U-shaped slots through which pass the shoulder screws 23 which are threaded into lugs 24 formed on the crucible on either side of heater element 29. The upper portion of the throat heater is held in place by the same clamping mechanism that holds the mouthpiece heater 25 in place. Before describing such clamping mechanism, however, mention will be made of the fact that the side of the mouthpiece heater in engageent with the top side of the dischar e spout is machined to provide a smooth surface. The top side of the discharge spout that is engaged by the mouthpiece heater is similarly machined so that with heater 2-5 in place an intimate contact is eflfected for maximum heat transfer from the heater to the discharge spout and mouthpiece. The forwardmost part of the heater 25, nearest the pot mouthpiece, is provided with an opening 26 which serves as the receptacle for a temperature sensing probe 27. The location of the sensing probe in the heater element itself has been found to result in a. very accurate control of the mouthpiece temperature.

The clamping mechanism for the mouthpiece heater 25 is formed by a pair of clamp studs 30 and 31 which are secured to the sides of the crucible as by screws 32 threaded directly into the crucible. Joining the two studs across the top of heater 25 is a clamp bar 33 which is provided with Ushaped slots through which the threaded portions of studs 30 and 31 pass. Fitted over the studs and bearing against bar 33 are too high temperature con1- pression springs 34 and 35 which are held in place by nuts 36 and 37. The lower extremities of the studs 30 and 31 are similarly joined by a second clamp bar 40 which bears against the throat heater 20. This bar is also provided with 'U-shaped's'lots through which the lower threaded portions of the studs pass. High temperature compression springs 41 and 42 are provided to bear against bar 40 and are secured in place by nuts 43 and 44. The arar-n-gement is such that regardless of the rise and fall of the mouthpiece temperature and the consequent expansion and contraction of the components of the'clamping mechanism the action or" the high temperature compression springs will hold the heater elements, and particularly the mouthpiece heater 25, in intimate contact with the discharge spout. This in turn means that the mouthpiece temperature can be maintained at a the desired temperature so that good quality slugs can be cast.

It is expected that many variations and apparently Widely dilferent embodiments of this invention can be made Without departing from the spirit and scope thereof. Therefore, it is intended that the foregoing specification and drawings be interpreted as illustrative rather than in a limiting sense.

What is claimed is:

1. In a metal pot for a linecasting machine having a reservoir in which metal is melted, an electrical heater for melting metal in the reservoir, a mouthpiece for engaging a mold, a discharge spout leading from said reservoir to said mouthpiece, a plunger for discharging molten metal from said reservoir through said mouthpiece, and an electrical heater element adjacent the mouthpiece for heating the mouthpiece, the improvement in combination therewith of means for resiliently biasing said mouthpiece heater element into engagement with the upper part of the discharge spout comprising a pair of threaded studs, one secured to each side of the metal pot, a clamping member extending between said studs and overlaying the mouthpiece heater element, a high temperature compres sion spring fitted over each stud to urge said clamping 'member against said heater element, and a nut threaded References Cited in the file of this patent UNITED STATES PATENTS 1,279,682 Fort Sept. 24, 1918 1,284,189 Hadaway Nov. 5, 1918 1,664,882 Hadaway: Apr. 3, 1928 2,025,687 Kemp Dec. 24, 1935 2,165,177 Goodbody July 4, 1939 2,450,428 Hazelett Oct. 5, 1948 2,887,742 Stern May 26, 1959

Claims (1)

1. IN A METAL POT FOR A LINECASTING MACHINE HAVING A RESERVOIR IN WHICH METAL IS MELTED, AN ELECTRICAL HEATER FOR MELTING METAL IN THE RESERVOIR, A MOUTHPIECE FOR ENGAGING A MOLD, A DISCHARGE SPOUT LEADING FROM SAID RESERVOIR TO SAID MOUTHPIECE, A PLUNGER FOR DISCHARGING MOLTEN METAL FROM SAID RESERVOIR THROUGH SAID MOUTHPIECE, AND AN ELECTRICAL HEATER ELEMENT ADJACENT THE MOUTHPIECE FOR HEATING THE MOUTHPIECE, THE IMPROVEMENT IN COMBINATION THEREWITH OF MEANS FOR RESILIENTLY BIASING SAID MOUTHPIECE HEATER ELEMENT INTO ENGAGEMENT WITH THE UPPER PART OF THE DISCHARGE SPOUT COMPRISING A PAIR OF THREADED STUDS, ONE SECURED TO EACH SIDE OF THE METAL POT, A CLAMPING MEMBER EXTENDING BETWEEN SAID STUDS AND OVERLAYING THE

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