GB417155A - Improvements in method and apparatus for investing dental casting patterns - Google Patents

Abstract

417,155. Moulding machines and processes. PHILLIPS, D. W., 2376, East 71st Street, Chicago, U.S.A. Sept. 29, 1933, No. 26856. [Class 83 (i).] A dental casting pattern is vibrated while it is being invested. A dental pattern 35, Fig. 9, is carried by a sprue 36 which is mounted on a crucible-forming holder 38 preferably of plaster of Paris, absorbent paper or other material which will absorb water from the investment material 33 in the container 22. The container is secured by spring clips 51 to a plate 49 at the end of an arm 42, an electrically controlled vibrator 53 being mounted above the container. The arm 42 with the pattern is lowered and raised twice before it is finally lowered, the vibrator 53 operating throughout. A second vibrator 28, Fig. 9, actuates an armature 26 forming part of a member 25 engaging the elastic closure 34 of the container. Downward pressure is exerted later in the operation on the container to cause a plug 41 to compress the investment and expel water therefrom. The movements of the arm 42 are derived from a cam 57, Fig. 4, through a follower 64, lever 62, and rod 55. The cam is rotated through substantially one revolution by a clockwork motor timed by an oscillating lever, with a weight wheel and spring, the driving spring being wound up to the correct degree through a rack and pinion actuated by a manual control 74, Fig. 1. The circuit of the vibrator 53, and in some cases that of the vibrator 28, are controlled by the movement of the winding- up rack. Manual control switches 124, 125 are also provided. Pressure is exerted on the container 22 by a member 95 which is pulled downwardly by a spring 98 and which may be swung over the rod 42.