Abstract: A casting machine including a control circuit which automatically controls ts operation. The casting machine includes a casting chamber which supports an alloy filled open-ended container whose open end faces the sprue hole of an investment casting ring. The control circuit couples a vacuum to the casting chamber while maintaining the casting chamber in its initial upright position. After a first timing interval, the chamber is inverted and the vacuum is decoupled from the casting chamber, and compressed air is applied to the casting chamber. After a second subsequent time interval the casting chamber is automatically returned to its initial upright position, the action of which causes the casting chamber to be automatically vented to the atmosphere.

Abstract: A drilling machine for drilling holes in plaster casts or models has a frame which supports a stationary drilling platform having an opening therethrough. A motor housing is positioned below the drilling platform and is vertically movable between a rest and a drilling position on two laterally disposed top guide shafts and a centrally disposed bottom guide pin. A motor is mounted in the housing and supports a drill chuck and drill bit which penetrates through the opening to drill a hole in a cast or model on the drilling platform when the housing is moved upwardly to its drilling position. A U-shaped handle pivotally mounted on the frame and engageable with the housing permits manual raising of the housing. Alternately, a pneumatic system is described which includes a piston arrangement for raising the housing to the drilling position independently of the position of the handle. During pneumatic operation, the handle may be locked in its rest position.

Abstract: A dental model cast includes an impression of at least one tooth and a substantially flat surface opposingly disposed relative to the tooth impression. The dental model cast is in the form of a plurality of segments. Each of the segments is removably mounted on a base cast and can be replaced in their original positions thereon. Extending from the flat surface of each segment is an elongate brass pin which is provided with a tapered free end. Each segment is also provided with a shorter tapered or conical pin which is made from an elastomeric material such as polyethylene. The base casting is provided with a polyethylene sleeve configurated to receive a portion of the tapered brass pin which extends beyond the flat surface. A tapered or conical opening is provided in the base cast which is configurated to receive the shorter tapered pin.