BEDEFRGBIT0036273EUROPEAN PATENT APPLICATIONA319811209EP8130092719810305800026819800313US1981120919814919810923198138 6B 22C 07/00 A 6B 22C 09:00 B 6B 22C 09:24 B 6B 22C 09:28 BenMethod of, and pattern for use in, forming a sand mould, and method of producing an annular casting using the mouldfrProcédé pour la fabrication d'un moule de sable et modèle utilisable et procédé pour la fabrication d'un moulage annulaire en utilisant ledit mouledeVerfahren zur Herstellung einer Sandform und dazu benötigtes Gussmodell und Verfahren zur Herstellung eines ringförmigen Gusses unter Verwendung der FormCATERPILLAR TRACTOR CO.Flesburg, Edward E.BEDEFRGBIT19811209198149

A pattern (11) for forming a sand mould for use in producing a one-piece annular casting (1) having a radially inner shell (12), a radially outer blade support (13), and a plurality of angled blades (14) extending in a spaced, annular array (22). The pattern includes a plurality of similar segments (15), each having an inner end portion (18) defining a portion of the profile of the shell, and an outer end portion (21) defining the profile of the blade. The segments are supported in annular array about a mandrel (25) and are circumscribed by a split ring (26) defining the pattern for the outer blade support portion of the wheel (10). The inner portions of the segments are defined by inclined side surfaces (16,17) which, in alternate ones of the segments in the annular array, converge and diverge toward the centre of the array. Upon completion of the forming of the sand mould aboutthe pattern, the mandrel and outer ring are removed, permitting the segments having the inwardly diverging side faces to be withdrawn inwardly from the array and permit the remaining segments then to be withdrawn inwardly therefrom.