GB187746A - Improvements in or relating to time alarms and indicators - Google Patents

Abstract

187,746. Miles, F. Aug. 10, 1921. Alarm mechanism; short-time movements; winding-apparatus, hard; keys, - Relates to alarms for indicating intervals of time of the type in which two independent springs actuate visible and audible indicating means. A pointer 2 adapted to move over a scale 1 is attached to a bush 5 carrying a toothed wheel 6 and mounted on a spindle 7 which spindle also carries an alarm spring 8 and a spring 11. The spindle 7 and bush 5 carry stops 9, 10 so arranged that when the key, Fig. 4, is placed on the spindle and turned it engages the stop 9 before the stop 10 and so winds the spring 8 ahead of the spring 11. The action of winding the spring 11 moves the pointer 2 to the desired marking on the scale 1. As soon as the key is removed the pointer is moved back by spring 8 under the control of the escapement wheel 17 governed by an escapement lever 20 oscillated bv a rod 21 attached to a suitable part 22 of a separate clock. When the pointer reaches zero a projection 23, on the toothed wheel 6 pushes a loosely pivoted arm 13 out of engagement with the alarm gong lever 15 and allows the alarm to be operated by spring 8. The wheel 17 carries staggered teeth 18 which are bevelled so that when the spring 11 is being wound the teeth 18 displace a bevel tooth 19 on the escapement lever 20 but when the spring is unwinding the wheel returns tooth by tooth as the lever 20 rocks. The rotation of the wheel 17 is arrested by the engagement of a pin 24 with the arm 13 when the latter is pushed out of engagement with the lever 15. Also by means of this pin the escapement wheel is held in such a position that the lever 20 rocks without coming into contact with the teeth 18 so that the clock may continue to work although the escapement wheel has stopped. The apparatus may be used for long or short intervals of time according to the part of the clock to which the rod 21 is attached.