| 摘要 |
A sheathed electric heater for use as an engine glow plug or the like is formed by providing a closed end metal sheath with a diameter larger than the finished diameter, Installing in the sheath a centered electric heating element having an enlarged diameter portion that engages the sheath adjacent to its closed end, the sheath and heating element being formed of compatible metals capable of being welded together by cold working, filling the sheath interior around the element with granular electrical insulating material, and swaging the assembly to reduce its diameter, extend its length, compact the insulation and cold work the engaged end portions of the sheath and heating coil so as to increase their engagement pressure and thereby establish a low resistance electrical connection between them. |
