Patent GB-735201-A (GB)
Title: Improvements in or relating to automatic fire shutters
Inventor: KIDD LEONARD FRANK
IPC: A62C2/10
Filed: 1953-02-09
Abstract: 735,201. Door-operating apparatus. MILNERS SAFE CO., Ltd. Jan. 13, 1954 [Feb. 9, 1953], No. 3545/53. Class. 65(1). [Also in Groups XXI and XXVI] A roller shutter is automatically closed by means comprising power-storage drive means, means to connect the latter with the shutter, means to engage the connecting means and allow the drive means to act, and means to disengage the connecting means automatically on raising of the shutter after it has been closed by the drive means. In the embodiment described, a fusible link releases a wound torsion spring which brings gearing into action and drives the shutter thereby to close it from any position ; the initial opening movement of the shutter thereafter automatically disconnects the spring, leaving the shutter free for operation by handgearing, but the disconnection may be prevented to allow the spring to be wound up with the shutter. The spring may be released for action independently of the fusible link, for testing. An indication of the extent to which the spring is stressed is provided. In the arrangement shown in Fig. 1 two roller shutters 11, 12 are connected by bevel gearing and a shaft 27 which is operated by a handwheel through a vertical shaft 23 and gearing 25 to open and close the shutters ; the shutters are counterbalanced by torsion springs in their barrels, and their speed of movement is limited by a governor 33 on the shaft 23. A helical torsion spring acts on a gear 40 in an anticlockwise direction and serves to lower the shutters when connected therewith through an idle gear 46 carried by an arm 45, Fig. 5, which is pivotally mounted on the spindle of the gear 40 and is pressed by a toggle spring 50 to a position in which the gear 46 is engaged with a gear 58 on the barrel of one shutter, as shown, or to a disengaged position. The spring is normally held wound up by a toothed pivoted detent 51 supported against the force of the spring by a trip lever 55 ; this lever is shown after actuation by a member 71 which is moved by a spring 83 when released by a fusible link or other device. On release of the wheel 40 as shown, an extension 52 of the detent 51 moves the arm 45 to the position in which the gears 46, 58 are engaged so that the spring drives the shutter barrel, the other shutter being operated simultaneously through the shaft 27. The initial manual opening movement after spring closing causes a pawl 57 to be moved by the wheel 58, restoring the arm 45 to the disengaged position and the detent 51 to the holding position so that the spring is disconnected and the shutters can be moved freely. In order to rewind the spring, the disengaging means is put out of action by a manually-operated arm 63 which holds the arm 45 in engaged position and places a member 68 under the pawl 57 ; opening of the shutter by the manual means then winds the spring, which is disengaged and held when the arm 63 is restored to its normal position. In a modification, the arm 63 and member 68 are replaced by a lever pivoted above the mechanism and having an arm arranged to lift the pawl 57 and another arm arranged to move the arm 45 into the engaging position. The amount by which the spring is wound may be indicated by a scale which is suspended from a winding drum geared to the wheel 40 and moves past a fixed pointer.