Patent GB-830161-A (GB)
Title: Cigarette lighter
IPC: F23Q7/00
Filed: 1957-04-26
Abstract: 830,161. Electric cigarette igniters. FENN, L. E. April 26, 1957 [April 26, 1956], No. 13389/57. Class 75(3) An electric cigarette lighter comprises an igniter unit removably located in a socket and including a low voltage heating coil, a transformer, a first circuit connecting the transformer primary to a relatively high voltage current source, a .second circuit connecting the heating coil to the transformer secondary of relatively low voltage to energize the heating coil and means for opening the second circuit in response to the temperature of the heating coils. In the arrangement shown in Figs. 1 and 3 an igniter unit 15 removably mounted in a socket 14 in a case 10 has provided at its lower end a heating coil 19 contained within and having one end connected to a cup 20 and the other to a stud 21 which is electrically connected to sleeve 22 through a body 16 and intermediately connected parts. Contacts 23, 24 connect the heating coil 19 to the secondary of a transformer 39. The igniter unit 15 when in the position of the socket 14, as shown in Fig. 3, is in the normal open position and when the coil 19 is to be energized a knob 17 of the unit 15 is depressed against the spring 25 to engage the contact 23 with the cuo 20 to complete an electric circuit to the coil 19. The contact 23 has bimetallic contact fingers 30 which engage over the rim of the cup 20 so that when the coil reaches an optimum temperature the fingers release the cup 20 to allow the unit to return to the open circuit position and permit removal of the unit 15 from the socket 14. To prevent the fingers 30 and the socket 14 being short circuited when the unit 15 is removed a wire 41, leading from the mains supply is connected to the primary winding 40 of an isolating step down transformer 39 through normally open switches 45, 47. The switches 45, 47 are closed, when the knob 17 of the unit 15 is depressed, through the intermediary of a rod 48 engaging a lever 49. To prevent damage to the coil 19 by prolonged energization a normally closed current responsive thermostatic switch 44 is placed in the transformer primary winding 40. The switch 44 contains a bi-metallic strip 57 which on being heated by the magnetic flux provided by a coil 58 is flexed to open the contacts 57a, 57b. To prevent overheating and damage to the transformer 39 due to igniter unit 15 being depressed to the closed position in the socket 14 for a long period, irrespective of the fact that fingers 30 have released the cup 20, a normally closed heat responsive thermostatic switch 46 is placed in the heat conductive relationship with the transformer 39. The switch 46 has a bi-metallic strip 53 which is flexed by excessive heating of the transformer 39 to open contacts 54, 55. In a modification shown in Figs. 4 and 5 bellcrank 62 mounted on a support 61 has one leg 64, covered by an insulating sleeve 66, which projects through a slot 65 formed in the socket 14 so that when the knob of the igniter unit 15 is depressed the bell-crank 62 is tilted to close, by means of its other leg 63, a normally open switch 59 in the circuit to the primary winding 40 of the transformer 39. A current responsive thermostatic switch 67 is screwed to the stud 36 so that current can flow through the switch 67 and the fingers 30 to the heater coil 19. The switch 67 has a thermoplastic material which upon being heated by the passage of a pre-determined amount of current deforms to open the switch.