US2360986A

US2360986A - Heat transfer in denture molds

Info

Publication number: US2360986A
Application number: US405691A
Authority: US
Inventors: Taub Francis
Original assignee: Individual
Current assignee: Individual
Priority date: 1941-08-06
Filing date: 1941-08-06
Publication date: 1944-10-24
Anticipated expiration: 1961-10-24

Description

Oct. 24, 1944. F. TAUB HEAT TRANSFER IN DENTURE MOLDS Filed Aug. e, 1941 4 Sheets-Sheet 1 FRANCIS TAUB INVENTOR. BY M A TTORNEY.

Oct. 24, 1944. F. TAUB 2,360,986

HEAT TRANSFER IN DENTURE .MOLDS Filed Aug. 6, 1941 4 SheetsSheet 2 I F RANCIS TAUB INVENTOR ATTORN EY Oct. 24, 1944. TAUB HEAT TRANSFER IN DENTURE MOLDS Filed Aug. 6, 1941 4 Sheets-Sheet 3 llllll MLUII H FRANCIS TAUB INV EN TOR.

ATTORNEY.

Oct. 24, 1944. F, UB 7 2,360,986

HEAT TRANSFER IN DENTURE MOLDS Filed Aug. 6, 194l 4 Sheets-Sheet 4 FRANCIS TAUB INVENTOR I WWW Patented Oct. 24, 1-944 HEAT TRANSFER IN DENTURE MOLDS Francis Taub, Brooklyn, N. Y. z I v i: Application August s, 1941, Serial No. 405,69l

9 Qlaims. (01. 18-341 In the molding. of dentures it has been customary to apply heat to the external surface of the flask, the heat being transmitted by con-- duction through the metal to the refractory or plaster mold and .therethrough to the denture material.

It has been found that the applied heat first reaches the outer surfaces of the denture and that it takes about thirty minutes before the heat travels inwardly until the temperature is uniform all through the denture.

Thermosetting denture materials such as those made of acrylic resin contain certain gases which escape during the time the material is subjected to heat. c

When the heat is applied from the exterior ,of the flask containing thev mold, "the outer part of the denture sets. first and traps the escaping thereof. This unevenly distributed cooling causes uneven shrinkage of the denture and warping and. broken teeth.

I have found in actual practice that when the heat is applied first to the interior of the mold, that the gases will be free to escape outwardly and no porosity or warpage will result. I have also found that when the cooling is applied first to the interior of the -mold that shrinkage is lessened and also uniform and the cured denture assumes the shape of the model more accurately and without breaking the teeth.

An object of this invention is to provide means for curing molded thermo-setting dentures by applying a heatingmedium and then-a cooling medium to the inner portion of the mold and denture and without being solely dependent on heat transference from the external surface of the flask.

Another object of this invention is to provide means for heating and cooling thermoplastic dentures to be molded byapplying a heating medium and then a cooling medium to the inner the central portion of the plaster mold and means for circulating a hot liquid into and out of the said chamber for heating, and .for circulating cold liquid into and out of the chamber for coolingthe mold and denture. V

Another object of this invention is to provide a thermo transferring hollo'w member designed for insertion into thesaidhollow chamber and preferably made of metal so as to be strongenough to withstand the molding pressure, and the said hollow member having openings in one wall thereof for introducing a heating or cooling medium thereinto.

Another object of this invention is to provide passageways through a wall of the flask and through the plaster and in alinement with the openings inthe thermo transferring hollow memher, so as to form passageways from the exterior of the flask to the interior'of saidhollow member. Another object of this invention is to provide a compact denturecuring device whereby a denture may be simultaneously'heated internally and externally and with thesame liquid.

Another object of this invention is to provide a thermo transferring hollow member having spring means for'compensating for shrinkage of material at time of curing'the dentures.

This application is a continuation in part of my application Serial No. 275,090, filed May 22, 1939.

With the above and other objects in view, the invention will be hereinafter more particularly described, and the combination and arrangement of parts will be shown in the accompanying drawings and pointed out in th claims which form part of this specification.

Reference will now be had to the drawings, wherein like numerals of reference designate corresponding parts throughout the several views, in which:

Figure 1 is "a top' plan view of the mold, the top cover being removed and the mold being partly broken away to' show a cross-sectional view of a thermo transferring device.

Figure 2 is a cross-sectional view, the section being taken as on line 2- in Figure 1.

Figure 3 is a cross-sectional View of the fluid circulating member.

Figure 4 is a front elevation of an assembled dental flask, having the fluid'circulating mem ber connected to ;the city pressure water supply line, or other sourceof fluid.

Figure 5 is a view of a modified top cover for the dental flask with-the fluid circulating memis transmitted'to the central portion of the mold, that is, to the hollow chamber-formed therein without the heating medium-coming in contact with the Outer metalflask.

By inside-out cooling is meant'that the heat is removed from the central -portionof the mold, that is,'from the chamber formed therein and without the cooling medium coming in contact with the outer metal flask.

Referring to Figure 8, the numeral 40 indicates a modified dental flask similar to theflask I0, but having two openings in the-upper portion 42 and leading to the interior thereof. One of the openings 41' allows passage into the flask fora tube 43 for delivering fluid into a modified thermo transferring hollow member- 45 shown in Figure 10. A tube 41 servesufor discharging fluid from the member 45. i

Figure 9 shows the flask in cross-section,

similar to Figure 2, but showing apertures 48 for.v

' culating

tubes

43, 41 frictionally inserted therein.

As shown in Figure 11, I have provided a denture curing device 50 whereby a denture may be simultaneously heated internally and externally and with the same source of fluid. The device 56 comprises a pot containing a liquid 52 and mounted on a stove 53. An inverted receptacle 54 is on the bottom of the pot. A denture flask compressing means 55 is mounted on the receptacle 54. The receptacle 54 has a riser tube 56 and a rubber tube 51 connected thereto. The upper end of the rubber tube 5'! is connected to the circulating tube 43 passing through an opening 4| in the flask 40. The tube 43 delivers fluid into the member 45, shown in Figure 10. The tube 41 serves for carrying the fluid discharged from the member 45 and leads back into the fluid 52 in the pot.

'It is to be noted that the inverted receptacle receptacle 54, the hotter fluid is forced up and I heats the member 45 and the denture l5 before the flask is heated from the outside. The outlet tube 4'! discharging hot fluid into the pot 5! begins to heat the flask from the exterior and the denture is thereafter heated simultaneously internally and externally.

Figure 12 is a side view of a modified thermo transferring hollow member 65 having spring means for automatically compensating for shrinkage of the'denture material during curing. As shown, the outer end walls 66 and 61 of the member 65 have elongated depressions S8, 69 serving to receive a bifurcated plate in slidable engagement therewith. A spring II is disposed between the flat wall 12 of the member 65 and the plate 10. The spring H is of arcuate form and serves to space the plate 10 from the wall 12. Under operating conditions the spring is compressed by excess denture material, and when the molded denture material starts shrinking, the spring ll automatically compensates for the shrinking of the material and keeps it under pressure. As shown in Figure 13, the plate 10 has

clearance openings

13, 13 for the'circulating

tubes

43, 41 shown in Figures 8 and l0.

- of the invention It is to be noted that when thick dentures are I to be treated; a very small quantity of liquid is placed'in'the'pot so as'to-only cover the receptacle 54 for internal. heating, the liquid not coming into contact withthe. flask. After a predetermined time of internal heating, the pot is filled as shown in Figure 11, when the curing will commenceexternally of the flask.

In accordance with the patent statutes I have describedand illustrated the preferred embodiments of my invention, but it will be understood that. various changes and modifications can be made therein without departing from the spirit as defined by the appended claims;- 1 1 Iclaim: y 1. In combination with a dental flask having upper :and lower plaster mold sections for curing dentures, s'aid.mold sections being formed to provide a cavity between them for denture material, a hollow metallic member imbedded in i one of said mold sections, said hollow member having passage means connected therewith and leading exteriorly of said flask; and means for circulating a fluid into and out of said passage means and said hollow member for imparting a predetermined temperature to said denture material.

2. In combination with a dental flask having upper and lower sections, a hollow metallic member in one of said sections, said hollow member having passage means connected therewith and I sections, said hollow member having passage means connected therewith, said mold having opening means and said passage means passing through said opening means, and leading exteriorly of said mold, and means for circulating a fluid into and out of said passage means and said hollow member.

4. In a denture mold designed for imparting a pre-determined temperature to the interior thereof, a flask having upper and lower plaster mold sections, a hollow metallic member in one of said sections, an outlet in said hollow member, said hollow member having passage means connected therewith and leading exteriorly ,of said flask, said passage means comprising an elongated tube mounted inside said outlet and extending to the far end thereof for delivering a fluid therein, said flask having an opening in alignment with said outlet, a tube secured in engagement with said outlet and in circumscrib-' ing relation with said elongated tube, said circumscribing tube terminating substantially at the inner face of said hollow member and serving for discharging said fluid from said hollow member.

5. A method for uniformly curing a molded denture in a metal flask having upper and lower plaster sections and having a hollow metallic member at the central portion of one of said plaster mold sections and at the central portion of said denture and without direct contact with the metal flask, which consists in circulating a hot fluid solely into and out of the interior of said hollow member until the interior of said mold reaches a pre-determined temperature, and then circulating a cold fluid solely into and out of the interior of said hollow member until said vm'old anddenture is cooled ito rolom :temperature.

i6. A methodriorrcuring a thermo-setting den- 'rture material 'inasectional mold'made .o'fgplaster *or'trefractory material to form punwarped and uniformly cureddenturea'whichiconsistsin form- :ing :a; chamber in the: interiorand central portion of one of the sections-of said mold, in l circulating a hot fluid into and out :of :said chamber, and

.=simultaneous'ly subjecting 'the whole exterior of said mold to a :pre-=determined-.x:uring temperature for isaid rdenture materials Y 'Z..A temperaturedmpartingdevice'forimparting; a pre+determined"temperature to the interior of :a plaster or'refractory material mold having upper and lower sections and an intermediate cavity formolding solid dentures, comprising a ahollowmeservoir :memberdesigned for imbedding "in one of said-mo1d;sections,;saidhollow member being out of contactawith said-moldcavity, and means ifor heating the interior 'of said' hollow rreservoir member. l 8. .A' temperature imparting-device for impart- :ing aJpre-determined temperature tothe interior of a plaster *orjref'ractory material mold 'having :upper and lower sections and an intermediateoavity for molding solid adentures, comprising 'a upper and lower mold sections defininga mold cavity therebetween, said :mold sections being ;made of plaster for molding and curing dentures ;by.imparting -a predetermined :temperature to the "interior and exterior ofthe mold, a hollow "metallic reservoir-member completely embedded in one of "said sections, :said hollow reservoir member having :passage means connected there- -with, said one of said sections having opening said "denture material.

imeans and said passage :means passing through said opening means and leading exteriorly of :said one of said sections, means for circulating a fluid into and out :of said passage means and :said hollow reservoir member, and means for simultaneously subjecting the exterior of said mold to 'a predetermined-rowing temperature for FRANCIS TAUB.