US1280631A - Device for heating metal-casting molds. - Google Patents

Description

- A. c. ATKINSON DEVICE'FOR HEATING METAL CASTING M OLDS.

APPLICATION FILED 0m. 3. 1911.

1,280,631. I Patented Oct. s, 1918.

ED STATES. PATENT OFFICE.

ALFRED CHARLES ATKINSON, 0 WELLINGTON, NEW EALAND.

DEVICE FOR HEATING METAL-CASTING Moths] Specification of Letters Patent.

Patented Oct. 8, 191 8.

Application fi led October 3, 191?. Serial No. 194,580.

7 have invented new anduseful Improvements in Devices for Heating Metal-Casting Molds; and I do hereby declarethe following to be a full, clear, and exact description of the same.

This invention has been designed in order,

to provide improvements in the heating of the molds used for casting small metal articles, and particularly used for casting artificial dentures and other dental work.-

These molds are formed by positioning a fusible wax model or pattern of the article to be cast in a metal flask'and surrounding it with an investment of plaster of Paris composition. This. mold is then heated to melt the model so that the material of which it is composed, will disappear and leave a mold of corresponding shape into which the. metal is run to form the casting themold being heated to insure of the proper running of the molten metal under the pressure usually employed in this class of casting.

In the operation of this process, it is advisable that the mold should first be slowly heated to melt the fusible model or pattern and to expel the moisture from the investment material, as its subjection to a quick heat renders it liable to uneven drying and consequently the destruction. or distorting of the mold. After the moisture has been expelled the heat may be raised to heat the mold to the necessary degree to provide for the efiective running of the metal. c

Theinvention consists in means whereby these voperationsof the initial slow heating and the subsequent quick heatingto a high degree, may be effectively carried out, and;

also embodies means whereby a visible indication maybe giventhe operator when the mold has been first sutficiently heated to exs. pel the moisture and then heated to thezpre-n determined degree necessary; for; the'casting; This feature of the invention is adaptedto be used in conjunction with ,the indicating means describcdin the specification ofmy application for Patent No. 123,143, dated:

30th September, 1916', and: which consists in a rod of material fusible at a highejr temperri ature than'that to which: the mold isto be: heated, that is embeddedrat one of its ends' in aplug of a material fusible at the tempera leading to the outside of such material. When the plug melts the rod is released and any approved shape incross section but genture to which the mold is to be raised for casting purposes. The plug is positioned within the investment material of the mold and .its rod extends centrallyina tunnel falls to one side. of the tunnel thereby indi-,

cating the fact that the desired temperature has been reached.

In fully describing the invention reference will be made to theaccompanying sheet of drawings, in which:. ,g Figure l'i'saa sectionalelevation of amolding flask ready for heating in the furnace.

Fig. 2' is a furnace.

Fig. 3 isan end elevation of the inma e;

Fig. 4. a side elevationthereof.

. Fig. 5 is a sectional end elevation ,,and-

Fig. 6 a sectional side elevation thereof, the molding flaskibeing shown in position in each figure. U Q' Referring first to Fig. 1, Arepresents the molding flask that is made of. metal and ,of,

erally of circular or elliptical shape. B represents the wax model or pattern that is embedded within the plaster of Paris .investment C in which also the runner holeB' leading to the model from one end of the mum temperature toWhioh the mold is-tozbe' heated, one end ofwhich is held in the plug D sorthat the rod will extend centrally with T in the tunnel E, and will then by gravity,-

fall to one side of the tunnel whenvthe plug D melts and loosensits-hold on the rod.

In thisinventionmeans'areeOIIibined-Rwith 7 p the rod D bywhich an indication-may bealso given when 'thetemperatureof the flask has been-heated to the degree necessary to expel the moisture from the "investment. I

These means consist inasecond plug F of a l fusible metal or otherfusible material that is of such a nature as tofuse at a minimum temperature slightly above that'joffthe boil Bing point ofi lwater, for instance,'ati230 Fah., and which plug is arrangedonthe' rod f D ati'a-isuitalole distance from its end. Orm

instead of a plug,a'disk of 'the material plan of the lower part' of flask is also formed- D iS7 he plug of fusible j may beused. This plug or disk then occu pies a position within the tunnel E in the molding fiaskand comes under the action of the heat of'the' flask so that when such heat reaches the specified degree,-,the plug:

ordisk will melt and thus show the operator that the mold has reached the required.

temperature and that all moisture is expelled therefrom. plug or disk F should. be at such a point on the rod i D" as tooccupy a position well witlrinthe mouth of the tunnel and thereby be: free from any direct action from the fiames of the furnace in which "the flask is "placedi The-melting ofthe plug, or disk-E will not inany way afiect' the rigidity fthe rod and its subsequent function;

Referring now to the 'rem'ainingfigures of the drawings which show theformoffurinace- *designedfor heating the mold, this is designed i to cause the heat from the burners to be evenly distributedaroundjthe whole circumference of the. flask 'A'. and-thereby to I uniformly contents.

'. dic'atingi means; before i described may be;

, The furnace designed comprises astand G having a fiat rectangular open topi or platform G at the opposite, ends-cf which, sockets' are formed." 'Each Qf these sockets--'-is adapted to receivethe vertical stenr J of a flask support J which support is formed as an arc in which the'flask A will 'rest; as'sh'own in Figs. 5* and 6. The flaskis thussupported at its two ends by means of the respective supports and it then extends acrosstlie top of-the platform G"; The supports are made removable from the sockets H so that different sizes and forms of supports to correspond with the "different sizes' andshapes of flasks to be heated,maybe substituted-asrequired. The top of the furnace is formed as a cover'K of the. approximate semi-cylindrical formshown; that 1s adapted to rest 'upon the *edges' oftheplatfornr Gi This cover' is" lined. with asbestos lining K or withother approvedvlinsulatingg material; It"there 'fore encircles 'thei'fiask A laid upon the'supports J and servesatoronserve the'heat around fsuchflask. The'endsof the flask areposi- 1 tioned' adjacent to the'ends of'thecover andv these latter eitdsare made with sight i-apermesa Lthereimin a line approximately with the?v center line. of such flask so that :therinviewedslwithout. raising the coverUrThe cover isralso'; formed with'za' vent or vents in in its xtop for. the: escape of the" fumes and-to insure ofathepropernpdraft around= tllGiSuTfabBZOf thefiaskzr The lowerqportion of the stand Orr frame:

is madeawith'ledges M arranged at inter-a vals in thevh'eight of the. stand and which are'f'adapted to receive and support: a plate N Zthat 1 carries. the burner by which the-furs It is necessary that the-- heat the whole area "ofthe' flasks Y of-thezburner main :may be provided with a will.

nace isheated. The distance ofc'tli'e burner beneath the flask is therefore adjustable at or arranged'inparallel verticallines'andspaced apart so Y that the flames will im pinge upon the flask upon the opposite sidesof. it's- "centei" line andthen follow the samewhole circumferential area of the flask, and any undue concentration of the hea't" upon the one portion the'reof will thereby be avoidedfi i course around theflask? In this manner the heat will beevenly distributed over the The-frame may, if desired bejprovidfed with aga'ge bar P extending horizontally; across'it at'each GDCl OI SI'dQ and so disposed intrelatlon to the-burner that the height of' the'flamesth'ereof :in relation to a sightline extendingbetween the-two bars, may be gaged by the operator. The operator, -know' ing from previous experiment or use, the height of flame in relation to thissight line, that gives best results in the preliminary heating of the mold zbefore referred to, may

adjustrhis flame accordingly or insteadof these bars being; attached: to the frame," a

bar It having; a similar"purpose may. be

fixed to the. sidcvor -end of the :burner: sup:-

porting plate-.N byimeans of a; .vertical.stay Ra .(FigsxQ and l) 1 attachedc'to suchplate;

This bari may: be madenadjustable in its on the lower end of othefstay. o

cheightby adjustingfnutsw'or other means The usual air supply. aperture-orslot S"* regulating sleeve. S" (Fig.4) by meansof whichzjthe air supply: may. beadjusted; at@

"1. fln' a device: for heating metal casting molds, a mold support ng :frame" consisting:

in; a stand havinga horizontal open top withremovable mold restsxat each 'end thereof; an ansu l ated zcover cfittingfover" suchjtop and I Y adapted to V inclose Y ther-mold," and a heatingburner supported: within lthe loweriportion of fthe'z stand and adj ustablein: ,heig-ht' thereon, substantially asfspecified '2'. Tn device :for heating metal casting molds;vv a the combination Jwith a i mold sup-' Y 7 porting framehaving an open horizontal topl' ,"with removable mold rests at ea'ch end thereoffoff-t a'sburner for 1 heating the *mold t Y arranged beneath 'such open top: and formed 1 Y by a 'maini having: jetnozzles arranged: in. two: parallel irows :extending upward 3 from weasel such main in respectively oppositely divergingi or vertical lines, substantially as speci- 3. In a device for heating metal casting molds, a mold supporting frame mounted on a stand and formed by an open horizontal top with sockets arranged one at each end thereof, and mold rests adapted to support the mold each formedvby a curved cross bar and a vertical stem that enters one of the sockets in the frame, substantially as specified.

l. In a device for heating metal casting molds, a mold supporting frame mounted on a stand and formed by an open horizontal top provided with means for supporting the mold thereon and a burner ar ranged beneath such top and supported by the stand, in combination with an insulated cover fitting over the stand top and formed with vision apertures in its ends, substantially as specified.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

ALFRED CHARLES ATKINSON. V

Witnesses:

W. ALEXANDER, v M. E; BROWN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

. Washington, D. G.

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