| 摘要 |
495,749. Coiling lamp filaments. BRITISH THOMSON-HOUSTON CO., Ltd. March 24, 1938, No. 9054. Convention date, March 24, 1937. [Class 83 (iv)] [Also in Group XI] In a method of making multiple coil filaments for electric lamps, the filament is wound on a mandrel, heated, and wound on a second mandrel. The second mandrel is then withdrawn, the coil is heated and the first mandrel is removed. A tungsten wire is wound on a mandrel and the whole is heated for 16 seconds at a temperature of 1500-1700‹ C. in wet or dry hydrogen inner electric furnace to remove strain. A second mandrel 15 and the end of the coil are then clamped by jaws 16, 17 moved in the direction of the arrow. Fig. 5, whilst the coil is fed through an offset hole in a rotary member 18. When a sufficient length has been coiled the rotation of the member 18 is stopped and a straight portion is left on the end of the coil. This length is severed at the centre by shears 21 and the mandrel 15 is withdrawn. The pieces are then placed in an electrically heated furnace at a temperature of 1675-2075‹ C., for 3-5 seconds. The first mandrel is then dissolved out. A similar process may be used for the production of triple &c. coils. Specifications 155,851, 218,674, [both in Class 39 (ii)], and 467,187, [Group XI], are referred to. |
