GB407493A - - Google Patents

Abstract

407,493. Door - operating apparatus. NEWMAN & SONS, Ltd., W., and SHEAD, H. C., 268, Hospital Street, Birmingham. Jan. 4, 1933, No. 236. [Class 65 (i).] In a system for unfastening and opening doors by the fall of a weight which is normally supported by a detent releasable when it is required to open the doors, as described in Specification 407,494, the detent is normally held in position by a trip lever which is released when an electromagnet is energized, so that the weight can disengage from the detent and fall in order to open the doors. The weight 2 is carried by a rod 13 attached to a dooroperating cable, and is normally supported by a hook 16 pivoted on the weight and engaging the nose 22 of a detent 23 pivotally mounted at 18. A latch member 25 pivoted to the free end of the detent 23 has a shoulder engaging a pivoted trip arm 27 and also has a bevelled portion which engages a fixed part 33 to raise the latch clear of the trip arm when the latter allows the latch to move to the right. The trip arm is normally held in the position shown by the pivoted armature 29 of an electromagnet 30. Energization of the electromagnet moves its armature clear of the trip arm 27, which is then free to be moved by the weight 2 acting through the detent 23 and latch 25 ; the movement of the latch carries it up clear of the trip arm, and the detent can then swing over to free the hook 16 and allow the weight to fall. The detent, the trip arm, and the armature 29 are returned to their normal position by springs. A cable 38 is provided for lifting the weight to its normal position after operation.