VACUUM CASTING FURNACE

• US 3,845,807 A
• Filed: 03/31/1972
• Issued: 11/05/1974
• Est. Priority Date: 04/01/1970
• Status: Expired due to Term

• Current Assignee: Howard T. Koon
• Original Assignee: Howard T. Koon
• Inventors: Koon, Howard T.
• Primary Examiner(s): Baldwin, Robert D.
• Application Number:
  US05/240,212
• Time in Patent Office: 949 Days
• Field of Search: 164/62,63,65,250,255,251,DIG.4,298
• US Class Current: 164/255
• CPC Class Codes: B22D 13/063 for dentistry or jewellery
• CPC Class Codes: E05B 65/0007 for gates for wire gates E06B11/021
• CPC Class Codes: Y10S 164/04 Dental

Abstract

Apparatus and method for molding or casting high temperature melting point material in a heated mold. The material is placed in a well or crucible communicating with the mold cavity and is heated in a closed muffle. When the material is molten, a vacuum is drawn in the muffle and the mold is tilted so that the molten material is propelled into the cavity and seated by the vacuum. Air can be admitted to the muffle behind the molten material to cause a pressure differential which enhances the drawing of the material into the mold. The apparatus can also be used, without the mold tilting action, for precision soldering such as used in constructing dental bridgework.

Claims

1. A furnace for working high temperature melting point materials, comprising:

a casing having a removable end portion;

a heated muffle in said casing, enclosing a chamber;

a mold assembly mounted in said chamber, said assembly including a porous mold having a pattern cavity therein, and a molten material holding well communicating with said cavity;

said mold assembly is pivotally mounted for tilting said mold assembly to deposit molten material from said well into said cavity;

vacuum means for applying a vacuum to said chamber through the porous material of said mold to draw the molten material into the cavity, means including a gas inlet for admitting gas to said chamber opposite to the vacuum means, and said inlet being positioned to direct incoming gas against the mold assembly for tilting the assembly.

2. A furnace according to claim 1 including, means for admitting gas simultaneously with tilting the mold assembly.

3. A furnace according to claim 2, wherein said vacuum means has an entrance opening in said chamber, said mold assembly having an open portion, exposing the porous mold, with means for sealing against the entrance opening when the mold assembly is tilted.

4. A furnace for working high temperature materials comprising, a muffle having enclosing side walls with an opening in one end, means for closing and sealing said opening, a gas porous mold with a well and a pattern cavity that is inserted through said opening into said muffle, means for heating said muffle, means for drawing a vacuum in said muffle, means for injecting a gas into said muffle after said vacuum has beendrawn therein, said gas injecting means includes a tube that directs the gas against said mold, said vacuum drawing means includes a vacuum tube that is positioned at an opposite side of said muffle from said gas injecting tube, and said mold being positioned in a tray between said gas injecting tube and said vacuum tube with said tray being pivotally supported in said muffle, whereby gas from said gas inserting means contacts one end of said mold and rocks said mold into contact with said vacuum tube causing the heated metal to move into the pattern cavity and causing a decrease in pressure on the side of said mold opposite said gas injecting tube with the gas exerting a pressure differential on the heated metal in the cavity.