US1485628A - schwartz - Google Patents

Description

March 4 1924. ,485,628

H. A. SCHWARTZ METHOD oF. CASTING Filed Feb. 16 1922 2 Sheets-Sheet 2 Patented Mar. 4, 1924.

UNITED STATES HARRY A. SCHWARTZ, OF DEFIANCE, GHIO.

METHOD 0F CASTING.

Application filed February 16, 1922. Serial No. 537,024.

T0 all whom t may concern:

Be it known that I, HARRY A.. SCHWARTZ, a citizen of the United States, and a resident of Defiance, in the county of Defiance and State of Ohio, have invented a new and Improved Method of Casting, of Which the following is a full, clear, and exact description.

This invention relates to an improved method of casting, and more particularly to a method of casting in permanent molds, an object of the invention being to provide a method in which the casting itself functions as a circuit closing means to control the ejection of the casting at the proper time.

A further object is to provide a method of the character stated, in which the electrie conductivity of the metal is utilized to control the ejection of the casting.

It is a Well-known fact that there is a wide difference in conductivity or resistance between metal in a molten state and in a solid state, and I utilize this factor in controlling the flow of electric current to cause the operation of electric means to insure the ejection of the casting from the mold at the proper time, hence, utilizing the casting itself to control the operation of its ejecting means, resulting in an automatic control Which is uniform and insures uniformity of the castin s.

gIt is to be understood that my invention has particularly to do With casting in permanent molds, in Which the temperature of the mold members is maintained constant Within a predetermined range of temperature, so as to prevent deterioration of the mold, but specifically relates to the automatic ejection of the casting at the proper time; thus, to obtain, independent of the pouring temperature of the metal and other variants, practically absolutely uniform castings in a given run and With each such casting, particularly When a ferrous metal is cast, characterized by predetermined denseness of grain, graphitic and ycombined carbon content, hardness, superficial chill if 'desired, and other physical and chemical attributes.

My improved method herein definedlhas special relation to my copending applications on methods of casting, Which may be 'identified as follows:

Application for method of casting, filed June 8, 1921, Serial No. 475,968. v

yApplication for method of casting,`1iled January 25, 1922, Serial No. 581,794.

Application for method of casting, filed February 6, 1922, Serial No. 584,548.

To sum up briefly: The underlying idea of the invention is a disassociation of the casting from all auxiliary structures or appliances instrumental in molding said casting, and, as the invention is preferably carried out, the necessity of disassociation is established or indicated by a measurable change in the electrical resistance of the casting or of the molten metal poured to form the casting While in the mold. According to the invention, the occurrence of this change, independent of the kind of mold employed, or the temperature of the molten metal When poured, or other factors affecting the rate of cooling of the metal in the mold, is the dominant governor in causing disassociation of the casting and the structures and appliances just above indicated.

l/Vith these and other objects in view the invention consists in certain novel steps in the method, as will be more fully hereinafter described and pointed out in the claims.

ln the accompanying drawings*- Figure 1 is a diagrammatic sectional view illustrating an apparatus, With which my improved method may be carried out.

Figure 2 is a fragmentary vieW in vertical section illustrating a modified form of mold to indicate that my invention is equally applicable for use in connection With molds having cores.

Figure 8 is an enlarged fragmentary view in vertical section on the line 3 3 of Figure 2.

- Throughout the specification I shall employ the term ejecting as indicative of the separation of the casting from the mold, but 1 would have it understood that this term is employed in its4 broac est possible sense to indicate any disassociation betweenv the casting and the mold, or any influence of the mold 'upon the casting.

Referring particularly to Figure 1, 1 and 2 represent the upper and lower mold members respectively, Which are chambered as shown at 3, for the circulation of a fluid to maintain the temperature of the mold Within a constant range, which forms the subject matter of my applications, Serial Nos. 475,968 and 584,543, above referred to.

4 represents the casting, Which is formed between the mold members 1 and 2, and 5 illustrates the mechanism Which directly controls the separation and ejection of the molds and which is indicated more in detail in my application, Serial No. 531,794, above referred to, and which is needless to describe and illustrate in detail, except to say that this mechanism is caused to operate by a pneumatic hoist device 1-1, the plunger rod 2 of which is caused to move vertically in accordance with the position of a valve 13, the latter being held in normal neutral position by a coiled spring 14. rThis valve 13 is operated by a rack bar 15 moved by a pair of magnets 16 ano 17 at the opposite ends thereof. These magnets 16 and 17 are included in electric circuit with a source of electricity 18, said circuits having manually operated switches 19 and 19 respectively, to include either of said magnets in the circuit with the electricity source. The electric circuits of the magnets 16 and l'are normally open and included in said circuits is a normally spring held contact member 20, which is caused to engage a fixed contact member 21 when a solenoid 22 is energized. This solenoid 22 is included in a relay circuit with a source of electricity 22, the Wires 23 and 24 of said relay circuit having` electric terminals 25 and 26 projecting through insulating sleeves 27 located in one of the mold members.

It is to be understood that the sleeves 27 effectually insulate the terminals 25 and 26 from the mold and that the inner ends of the terminals 25 and 26 are flush with the inner face of one of the mold members, so as to make direct contact withA the molten metal and casting 4 in the mold.

As terminals l preferably employ tungsten wire, and as insulating sleeves I preferably employ alundum. As a matter of fact, the sleeves 27 and the Wires or terminals constitute plugs which are fitted within the mold member and spaced apart, se that the electric circuit in the relay must be closed by the casting itself. lt is, of cou-rse, immaterial as to the location and arrangement of these terininals, but it is important that they be so situated as to require the current to pass directly through the casting.

As above stated, it is a well-known fact that there is a wide difference in electric conductivity between molten metal and solid metal or the casting resulting from said molten metal. There is a sharp curve in the degree of conductivity between the metal in its molten state and as it begins to solidify, and it is to be understood that this -factor is to be utilized as a circuit controlling means, whereby the casting ejecting mechanism is set in operation when the casting reaches a solid state.

1t is, of course, apparent that the amount of current necessary to operate the solenoid 22 is capable of a Wide variation or adjustment, so that suflicient current will pass through the casting to cause the ejection of the casting only when the casting reaches the desired setting point.

It Will thus be seen that with my improved method, the casting itself functions to control the timing of its own ejection, and While in my previous application above referred to, I utilize temperature as the controlling medium, in this present case I utilize the electric conductivity of the metal itself.

In operation, when the casting reaches a predetermined setting point or solidity, sufficient current can pass through the same to cause the operation ef the solenoid 22 and the movement of the contact member 20 against contact 21 and close the circuits with the electromagnets 1G and 1T in accordance with the position of the manually operated switches 19 and 19 respectively, as will be readily understood, particularly when the method is considered in connection with my other applications.

It will, of course, be understood that predetermined indication on the dial of a milli-v voltmeter (not shown) in suitable electric circuit with said terminals, may heV merely the signal, according to one possible way of carrying out the invention, for manually suitably operating rack 15 or valve 13; but, the operation of the parts is preferably automatic as hereinabove described.

lNhen the casting is ejected, it is caused to fall within a receptacle 28 having asbestos powder 29 therein, to allow the casting to slowly cool and soften any chilled surface Which may form thereon, whereby the casting is readily machinable without annealing the same.

To illustrate the fact that my invention is equally applicable for use in connection With molds having cores as Well as those Without the cores, I have shown in Figures 2 and 3 a mold construction in which a core 30 is employed and is lvertically movable with relation to a pair of horizontally movable mold members 31 and 32. In this form of mold it is also to be unnerstood that I utilize means for maintaining a constant, range of temperature both in the mold members and the core, and l have illustrated iuid carrying or directing pipes 33 for this purpose, it being understood that the mold members andthe core are both hollow and that there is a control of fluid regulation which carries off excess heat and thereby insures a constant range of temperature, which forms the subject matter of my applications, Serial Nos. 475,968 and 534,543.

In the form of mold illustrated in Figures 2 and 3, the core 30S-is caused to move vertically and the mold members 31 and 82 are caused to move horizontally through the medium of a pneumatic hoist device 34, which is connected directly with the core 30, and which also operates a vertically movable rack bar 35, the latter operating a pinion 36 on a short shaft 37. On the extreme end of this shaft 37 a second pinion 38 is located, which engages a pair of rack bars 39 and 40 and said bars 39 and Ll() being connected respectively to the mold members 31 and 32, so as to cause the latter to move in opposite directions.

In this form of mold I preferably have a. pouring spout 41 communicating with the lower end of the casting space, but it is obvious that the invention is not limited to any particular construction of mold or manner of pouring, and I have illustrated this form of core mold simply to indicate that the invention is applicable to a core mold as well as with other forms ofmold.

I claim:

1. The method of casting which involves introducing molten metal into a mold, registering the cooling tendency of the metal as it passes from the molten towards the solid state while in the mold, and timing the instant of disassociation of the casting and the mold in predetermined relation to said registration.

2. The method defined in claim 1, wherein such registration is a registration of a change in the electrical conductivity of the metal inthe mold.

3. The herein described method of casting, consisting in introducing molten metal into a mold, and controlling the time of ejection from the mold by the electric conductivity of the casting.

4. The herein described method of casting, consisting in introducing molten metal in a mold, automatically ejectingthe casting from the mold, and timing the ejection of the casting in accordance with its electric conductivity.

5. The herein described method of casting, consisting in introducing molten metal into a mold, ejecting the mold when the casting reaches a predetermined solidity, and controlling the time of such ejection through the medium of electric means, the current of said means being caused to pass through the circuit including the casting itself.

6. The herein described method of casting, consisting in introducing molten metal into a mold, and automatically disassociating the casting from the mold when the casting reaches a predetermined electric conductivity.

7. The herein described method of casting, consisting in introducing molten metal into a mold, allowing the metal to change from a liquid to a solid state, and controlling the physical and chemical properties of the casting by ejecting the casting from the mold when the casting reaches a predetermined electric conductivity.

8. The herein described method of casting, consisting in introducing molten metal into a mold, allowing the metal to cool to a predetermined temperature, and controlling the physical and chemical properties of the casting by ejecting the casting Jfrom the mold when the casting reaches a predetermined electric conductivity.

9. The herein described method of casting, consisting in introducing molten metal into a mold, allowing the metal to change from a liquid to a solid state, and controlling the further rate of cooling by ejecting the casting from the mold when the casting reaches a predetermined electric conductivity.

10. The herein described method of casting, consisting in introducing molten metal into a mold, allowing the metal to cool to a predetermined temperature, and controlling the further rate of cooling by ejecting the casting from the mold when the casting reaches a predetermined electric conductivity.

11. The herein described method of casting, consisting in providing a mold having a core member, introducing molten metal into the mold around the core member, allowing the metal to change from a liquid to a solid state, and controlling the removal of the core member by ejecting the core member when the casting reaches a predetermined electric conductivity.

12. The herein described method of casting, consisting in providing a mold having tivity.

HARRY A. SCHWARTZ.

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