| 摘要 |
1,251,952. Moulding commutators. HOOVER Ltd. 29 Nov., 1968 [30 Nov., 1967], No. 54621/67. Heading B5A. Commutator bodies are compression or transfer moulded in a rotary press comprising a plurality of upper and lower platens which are indexed through a plurality of stations, including a station at which pressure is applied by the platens to a mould located on the lower platen and which mould is removable therefrom at an unloading/loading station where the platens are spaced apart. Different sized commutators may simultaneously be moulded employing removable moulds of the same external size. In a transfer moulding process the mould comprises an upper member 10, provided with a sprue 11, and a lower member 13 aligned at shoulders 15, 16 within a chase 12. A cylindrical external commutator shell is located within chase 12 and a commutator bush on pin 14, the separation into segments being carried out after moulding. The mould is preheated and located within a cylindrical recess (21), Fig. 2 (not shown), of a lower platen (20) with moulding material, which is located above member (10) within recess (21), being forced into the mould by a ram (24) attached to the upper platen and sliding within the recess (21). The mould may be ejected from recess (21) by lower platen ejector (27) or the ram (24) may be provided with a recess in the lower face into which moulding material flows whereby the mould is ejected from the recess (21) on raising the ram (24). Alternatively, the ram may form part of the mould, when ejector (27) is used. In a compression moulding process, Fig. 4 (not shown), the upper mould member is downwardly displaced during moulding. |
