| 摘要 |
<p>1,034,556. Timed control of electric circuits. HUSQVARNA VAPENFABRIKS A. B. Dec. 7, 1964 [Dec.19, 1963], No. 49662/64. Heading G3T. A time switching device for electric apparatus, particularly micro-wave ovens, includes two or more holding circuits for a relay controlling the current supply to the apparatus, each circuit having a manual switch in series with a second switch, and a power driven timing cam or the like which is arranged to open each of the second switches momentarily, on the one hand after a time specific to the respective holding circuits, and on the other hand at moments corresponding in each holding circuit to the sum of the specific, individual time of that holding circuit plus the individual time or times of one or more of the remaining holding circuits. A choice of effective holding times is thereby afforded corresponding to the manner in which the manual switches are actuated. When input terminals 21, 22 are energized, current flows partly through the hot cathode type transmitter tube 5 and simultaneously energizes motor 4 through break contact 201 of relay 2. The motor, through cams corresponding to A to E in the timing diagram, Fig. 2, operates switches 10 to 14. After an interval corresponding to a sufficient heating of the tube, cam A closes switch 10 to energize a starting relay 2 so that it contacts 201, 202, and 203 move to positions wherein the motor is connected to switches 11 to 14, a manual switch 20 is connected to terminal 21 through contact 202, and relay 2 is held through contact 203. The motor stops and the cams are returned in known manner by a spring. If switch 20 and another manual switch 3 are now closed, a principal relay 1 is energized to close a contact 101 in the main circuit of tube 5 which starts operating. A predetermined time of operation varying from 20 secs to 5 minutes in steps of 20 secs, is obtainable by four press-button selector switches 15, 16, 17, 18. These may be marked with their characteristic time intervals and be of different colours, and are interconnected for automatic re-setting singly or in any combination. When set, the closing of switch 20 makes another circuit to terminal 21 through the manipulated switches 15-18, the corresponding switches 11-14 and contact 102 of relay 1 so energizing the motor again, and this circuit is maintained until the switch 11-14 in question is opened. Relay 1 then drops off and the cams are returned to home position. In a modification where no initial cathode heating is required members 2 and 14 are omitted, Fig. 3 (not shown), contacts 201-203 are replaced by permanent connections corresponding to the aperture positions of these contacts.</p> |
