| 摘要 |
1,213,549. Electrical systems for automotive vehicles. DR.-ING. H. C. F. PORSCHE K.G. 18 Dec., 1968 [20 Dec., 1967], No. 60180/68. Heading H2H. The rear window 1 of a motor vehicle is heated by means of two heating elements 2, 3 supplied from an electrical source 11 comprising the battery 13 and generator 12 of the vehicle, switching means being provided whereby the heating element 3 only is energized should the voltage of the source 11 fall below a predetermined value. A two-position manually operated switch 15 may be moved to a first position wherein contacts 18, 19 are connected to energize a relay 24 thus closing contact 25 to supply the heating element 3. Further movement of the switch 15 interconnects contacts 20, 21, 22 whereby a relay 32 is also energized to operate contact 28 to open contact 29 and close contacts 30, 31 thus energizing both heating elements 2, 3. The relay 32 is designed to be voltage responsive whereupon should the voltage of the source 11 fall the relay drops out to remake contact 29 such that the element 3 only is energized. |
