| 摘要 |
877,526. Making composite bushings; rotary work-holders; mandrels. GIEREN, H. Oct. 9, 1958, No. 32283/58. Classes 83 (2) and 83 (3). [Also in Group XXIII] In a method of making composite bearing bushings of steel lined for example with lead, bronze a steel cylinder having a length and diameter far exceeding that of the required bushing but with a substantially equal wall thickness in the bushing is lined on the inside with lead bronze by centrifugal casting during which deformations may occur in the cylinder, the latter subsequently being machined by turning on the inside to attain uniform thickness of the lining and finished on the outside before dividing into sections which are first pressed to form semi-cylindrical half-shells and then finished on the inside. The steel cylinder 1 may be produced from plate or seamless tubing. Concentric-cylindrical machining of the lining 2 is effected after the composite cylinder has been freed from scale by pickling and while it is held in true cylindrical form by a sectional clamping die 3. External finishing of the steel backing cylinder 1 is effected by a tensioned grinding belt 17 driven by a motor 20 (not shown), the composite cylinder being mounted in a sectional mandrel 7, e.g. of a non-ferrous metal, expanded by a conical shaft 10 rotated by a motor 11 (not shown). The shaft 10 is mounted in bearings suspended by arms 14 pivoted about a shaft 15, the cylinder thus being resiliently biased towards the belt 17 during grinding. The grinding belt 17 may extend the full length of the cylinder or may be of narrower width and move to and fro. After machining, the cylinder is cut up and the pieces pressed to form half-shells which are finished by broaching. In an example given, 120 bushing half-shells are produced from a cylinder 240 mm. long and 860 mm. in circumference, the steel backing being 1 mm. thick. |
