| 摘要 |
1,172,799. Riveting. FORD MOTOR CO. Ltd. 30 May, 1968 [1 June, 1967], No. 25882/68. Heading B3U. A thermoplastics lens 11 is fastened to a metal lamp holder 21 by studs 19 integral with the lens and a thermally compensating member 25 is interposed between the upset end of each stud and the holder. The lens is acrylic-type plastics and the member is polyethylene in sheet form with a series of apertures for the studs. The assembly is clamped before fastening and the stud end heated to 300‹ to 325‹ F. by a tool 31 which then deforms the stud. The tool may have a decorative pattern on its upsetting face. The tool contacts the stud until the shank is plastic and then the upset head is forcibly cooled either by circulating air, water or oil through the tool or withdrawing the tool and using a further cooled tool. The head sets before the shank so that tension is applied to the assembly as the shank cools. The coefficient of thermal expansion of the member 25 is such that its change in thickness under temperature changes is substantially equal to the difference between the thickness change of the shank and the metal holder. The allowable deviation from this equality is clearly defined in the Specification. |
