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US 4,950,442 AGranted
Method for manufacturing thermoplastic resin racks
AssigneePolyplastics Co., Ltd.
InventorsShigekazu Tanimoto, Toshiaki Nakamura, Katsuyoshi Satoh
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Abstract
A rack of a thermoplastic resin is produced by heating a rod of a thermoplastic resin so that the temperature of at least the surface of said rod reaches a level within a range expressed by the equation, ##EQU1## (wherein T is a melting point of a resin forming a matrix for said rod), and thereafter forming a rack in one or both surfaces of said rod by a toothed roller and a grooved guide roller which are paired with each other, or a pair of opposed toothed rollers.
Claims5
A method for manufacturing racks of thermoplastic resin comprising the steps of:
- (a) heating a preformed rod which consists essentially of a polycrystalline thermoplastic resin until at least the surface temperature T.sub.s of the rod is within a temperature range expressed by T-20.degree. C..ltoreq.T.sub.s <T, where T is the melting point of the polycrystalline thermoplastic resin;
- and thereafter
- (b) forming a gear rack in at least one surface of the rod heated according to step (a) while said surface temperature T.sub.s is within said temperature range, wherein said step of forming said gear rack includes the steps of;
- (i) heating the surface of a toothed roller so that the surface temperature T.sub.r of the toothed roller is within a temperature range expressed by T-30.degree. C..ltoreq.T.sub.r <T, and
- (ii) passing said heated preformed rod between said heated toothed roller and another roller opposite said toothed roller so as to cause gear teeth to be formed in said at least one surface of said preformed rod by means of said heated toothed roller.
2 more elements
Dependencies are inferred from the claim text.