GB590733A - Improvements relating to casting molds for making metal castings - Google Patents

Abstract

590,733. Moulds; mould jackets. CASTINGS PATENT CORPORATION. Nov. 10, 1944, No. 22230. Convention date, Oct. 21, 1943. [Class 83 (i)] A mould is provided with a runner having a pocket 28 for the first part of a pour, containing dross, cooled metal, &c. The pocket has vent holes 32 masked by a metal shell 36, Fig. 4, to prevent undue leakage of molten metal, and a baffle 37 to reduce splashing and prevent premature blocking of the vents. A header tube 22 is fitted to the runner which is reduced in cross-section at 40, to prevent air from being drawn in, and curved'to ensure non-turbulent flow to the pocket. When the pocket is full, the metal flows through a restricted passage 44 to a wide passage 26 leading to the mould cavity 12 and acting as a shrink bob. Preferably, the passage 26 enters the cavity 12 at the bottom and the mould is tilted slightly so that the metal enters as described in Specifications 546,906 and 546,991. The pocket 28 may be formed in the plaster or other mould investment 14, but preferably it is formed in a separate investment 46, 48 divided vertically and supported by a metal shell 36 which is similarly divided but doweled at 55 and clamped together. The shell 36 has spaces 62 at the corners to reduce the machining required and the risk of breakage of the parts 46, 48. One or both of these parts is provided with seal edges 64, Fig. 7, but these are not provided around the casting impression proper unless fins thereon are unobjectionable. The runner segment is adjusted on guide supports 58 to align it with the mould passage 27 and is clamped to the mould by a cam 60. The mould has a riser tube 20 and is supported between shell members 16, 18 preferably of metal.