| 摘要 |
As seen in plan view, the upper edge 16 of an up-and-over door carries cam plate 15. Horizontal arm 10, rotatable by an electric motor about vertical axis 10A, carries a roller which co-acts with plate 15, when arm rotates from A to D, to start door opening. At D, the door balance spring starts to move the door fully open, and the arm rotates on to A to await the next door opening. Arm 10 carries a latch plate co-acting with manually operable, spring biased latch 13. A motor control circuit is described. <IMAGE> |
