GB198932A - Improvements in and relating to electric heating units - Google Patents

Abstract

198,932. British Thomson-Houston Co., Ltd., (General Electric Co.). July 24, 1922. Wire resistances, embedded, encased, and threaded.-A heating unit of the kind in which a resistance wire is embedded in a compact mass of insulating material within an outer sheath and is provided with a terminal 10 at each end, is closed by an insulating washer 26 which is pressed against the sheath 18 by a lug 27 secured to the terminal. In order to fill the sheath before it is finally closed the outer end of one terminal 10 is held centrally of the sheath by means of a starshaped washer (not shown), the inner end being held by a washer 16. The other end of the sheath is closed by a solid washer. The sheath is filled through the star washer with insulating material such as magnesium oxide and the sheath then closed by a solid washer and swaged. The ends of the sheath are then cut off to expose a portion of each terminal, which is then formed with notches 25, the washer 26, treated with china wood oil, being placed over each terminal. The lugs 27, of soft metal such as brass, are then placed over the terminals and compressed to force the metal into the notches 25 and so secure the lugs to the terminals. Nuts 32 are provided on the threaded ends of the terminals to secure the supply leads 33. The resistance wire 17 is screwed on to the inner ends of the terminals 10.