| 摘要 |
An electrical switch has a casing, fixed and moving contacts, and an internal operator turning and moving the moving contact relative to the fixed contact for switching. The casing has an opening through which an engagement part of the operator is accessible from outside for engaging a pull chain to turn the operator. The casing has a tubular part by which the switch may be mounted and through which the pull chain extends. The tubular part, being molded, has an inner surface defining a passage for the pull chain, an outer surface bearing a screw thread for engagement by a threaded nut, and, in a transverse cross-section, four recesses between the inner and outer surfaces to alleviate deformation of the screw thread due to shrinkage in molding. |
