| 摘要 |
928,982. Moulds. PRECISION METALSMITHS Inc. Oct. 13, 1961 [March 30, 1961], No. 36898/61. Class 83 (1). A mould made by the lost wax process has a gating system including a sprue 10 defined by closely spaced opposed wall surfaces and a pairing cup 15, and a number of workpiece mould cavity pods 20 carried by the sprue, the minimum volume ratio of the gating system to mould cavities being about “ to 1, the gating system having a minimum cross-section dimension of about # inch, and the inner wall surface defining a passageway through the sprue, the passageway having a cross-section area of at least <SP>1</SP>/ 3 the cross-section area of the sprue. The heat-disposable sprue pattern is in tubular form and the mould patterns may be mounted on both the inner and outer surfaces as shown in Fig. 2. The openings 13 vent the interior of the tubular sprue pattern during dipping. |
