GB457979A - Improvements relating to alarm clocks - Google Patents

Abstract

457,979. Alarm clocks. JUNGHANS AKT.-GES., GEB., Schramberg, W³rtemberg, Germany. June 6, 1935, No. 16472. Convention date, Aug. 7, 1934. [Class 139] An alarm clock wherein a stopping lever 3 by entering a recess in a disc 2 connected to the alarm escape wheel 1 always stops the latter in the same position, is characterized by a cam 14, 15 which rotates more slowly than the wheel 1 and which cam, after a certain number of revolutions of the said wheel each controlling a signal of short duration, prevents the stopping lever 3 from again entering the said recess and from again stopping the alarm escape wheel 1, so that a signal of longer duration is given. The cam 2 rigid with the alarm escape wheel 1 coacts with the lug 4 of a lever 3 which is rigid with levers 7 and 8 and is turned clockwise about pivot 19 by spring 17. Lever 7 has a pin 20 coacting with a twelve-toothed ratchet 9 which is turned once an hour through its spring 12 connection with a wheel frictionally mounted on the minute spindle 10. Lever 8 coacts with a cam 14, 15 which is on the alarm spring shaft 13 and has a leaf-spring 16 covering the lower dwell 15 ; the shaft 13 rotates clockwise and drives the shaft of wheel 1 during the alarm. At the alarm release time, the hammer shaft 6 is freed by a settable face-cam in the known manner, but the top of lever 3 still locks an arm 5 rigid with shaft 6. Spring 17 and pin 20 hold ratchet 9 whilst shaft 10 continues to rotate, until spring 12 has been stressed sufficiently to overcome this hold. Wheel 9 then rotates suddenly one tooth, moving parts 7, 3, 8 to the left so that arm 5 and shaft 6 are released fully. The alarm sounds and parts 1, 2 rotate counterclockwise until, after one rotation of cam 2 (alarm duration of two seconds), lug 4 drops off the high part of cam 2 and lever 3 again locks the arm 5. During this time, the top of lever 8 is on the low dwell 15, the cam 14, 15 rotating clockwise. At the end of five minutes, the next tooth of wheel 9 again releases the parts to give a second short warning signal; lever 8 still being on dwell 15. After another five minutes and at the next, third tooth of wheel 9, however, lever 8 rises on to the high dwell 14 and since the end of lever 8 runs on part 14 and the outer surface of spring 16, it holds the lever 3 to the left, so that it can no longer relock the arm 5 and hammer spindle 6. The alarm then continues to ring until the alarm spring runs down or the alarm is stopped manually in known manner. During winding cam 14, 15 is rotated counterclockwise so that the end of arm 8 returns under spring 16.