GB558322A - An improved device for the release of clockwork and like intermittently released driving mechanism - Google Patents

Abstract

558,322. Clocks. LANDIS & GYR SOC. ANON. June 23, 1942, No. 8580. Convention date, June 28, 1941. [Class 139] In a clockwork or like mechanism with intermittent or periodic release means for the driving mechanism a device is provided for absorbing any additional or abnormal driving moment the device comprising two coaxial ratchet wheels with oppositely arranged teeth connected by a resiliently member which tends to hold the wheels in a definite angular position and engaged by pawls integrally connected. The minute shaft 4 is driven from a spring drum 6 through gearing 5. The gearing 5 also drives through a gear 7 a shaft 8 on which is fixed an excapement wheel 9 and mounted loosely a similar wheel 10 with the teeth inclined in the opposite direction. A rod 11 fixed to the wheel 9 extends through a slot 12 in the wheel 10 and a similar rod 13 fixed to the wheel 10 extends through a slot 14 in the wheel 9. The rods 11, 13 are spread apart to the limit of the slots by spring 15, so that the wheels 9, 10 are at an angular position relatively. Pawls 16, 17 rigid with a shaft 18 engage the wheels 9, 10 so that when pawl 16 rides upon the circular peripheral part of the tooth, the pawl 17 engages a tooth space. A gear wheel 19 in one with the wheel 10 drives a shaft 23 through gears 20, 21, 22. The shaft 23 carries the disc 24 of an electromagnetic brake and also an escapement arm 25. Coacting with the arm 25 is the abutment arm 26 of a four-arm oscillating lever 26, 27, 28, 29 turning about a shaft 30 and through a pin 31 on arm 29 controlling the spring arms 32, 33 of the armature 34 of an escapement relay having coils 35, 36. A pin 37 on wheel 21 coacts with the arm 27 and with the inclined face 28a of the arm 28. If the normal driving moment acting on the hands 2, 3 actuate the relay 34, 36, the armature 34 tilts towards coil 35 and spring 33 strike the pin 31 and releases arm 25 bringing arm 28 with part 28a into path of pin 37. The spring 6 now turns the hands 2, 3, the pawl 17 rises on to the peripheral part of the next tooth while pawl 16 slides into the next space. During this movement, the arm 25 has made a few revolutions and the pin 37 has moved against 28a moving it to one side and oscillating the lever 26-29 back, the arm 26 locking the arm 25. Further action of the relay tilts the armature 34 towards coil 36, rocking arm 27 into the path of pin 37, the lever 26-29 being restored at completion of the revolution of 21. If an additional driving moment due to wind pressure on the hands acts, the only effect is to move wheels 9, 10 relatively and stress spring 15 further.