GB795817A - Improvements relating to spring wound mechanisms - Google Patents

Abstract

795,817. Spring-actuated door-bells. GENT & CO., Ltd. Feb. 9, 1956 [Feb. 28, 1955], No. 5888/55. Class 10. [Also in Group XXXVIII] A spring-actuated door-bell of the type in which the spring is wound by rotation of the bell-cover has an indicating device to show when the spring has run down beyond a predetermined point. The bell shown comprises a base 1 supporting pins 7a, 7b, 7c and a rotatable spindle 4. The pins carry a triangular plate 8 held in position by a spring strip 10, the plate serving as a bearing for the spindle 4 and axles 19, 25 and a push-rod 30. The bell-cover 11 is screwed on to the spindle 4 and when rotated winds a spring 5 attached to the spindle and to the pin 7a. A gear-wheel 20 is secured on the spindle and this drives, whenever the bell is operated, a pinion 21 integral with a toothedwheel 22 rotatably mounted on the axle 19. This rotation effects, whenever the striker arm 24, is free, oscillation of the arm about the axle 25 through the engagement with the wheel 22 of a striker arm part 23. The bell push-rod 30, which is spring-biased outwardly, carries a conical flange 32 which normally contacts the striker arm part 33 and prevents the bell ringing. Inward movement of the rod, however, removes the stop flange 32 and allows the arm 24 to oscillate. Pivoted at 7a is an indicating member 52 biased by a spring 53 in a clockwise direction. Such movement is prevented when the spring is sufficiently wound by a bell-crank lever 40 pivoted about the pin 7b and clockwise biased by a spring strip 43. The arm 42 of the lever 40 is spring-urged against the spring 5 whilst the arm 41 has a notch 50 which holds, through an abutment 51, the member 52 against clockwise rotation as long as the spring 5 is sufficiently wound. On expansion of the springs to a predetermined point the lever 40 moves the notch 50 from the abutment 51 and the member 52 springs into a " spring rundown " indicating position which needs to be positively re-set by winding the spring and pressing the member 52 inwardly. Fig. 5 shows the bell used in combination with the fire detector 74 of Specification 768,353, [Group XXXVIII]. Here the push-rod 30 is moved inwardly by a bevelled edge of a slot 63 in which the rod is located, and which is formed in a strip 62 slidably attached to a mounting-plate 60. The strip 62 is formed with feet 70, 71 which are engaged by the part of the detector which drops on actuation of its bimetallic strip due to temperature rise.