GB433746A - Improvements in electric clocks - Google Patents

Abstract

433,746. Clocks. JARRY, A. G., 17, Rue BrÚa, Paris. Jan. 8, 1935, No. 647. [Class 139] In a clock wherein an electric motor drives the hands directly or winds the mainspring, the rack of the striking mechanism actuates the hammer directly and is lifted by meshing with a normal wheel in the reduction gearing driven by the motor. The rack 5 is pivoted at P to a trip lever 6 pivoted at 7, and is normally held, as shown in Fig. 1, with its projection 14 on the top of an arcuate stop 15 by a spring 16 anchored at its lower end. The half-hour pin 2 on the control wheel 1 first rocks the trip lever 6 anticlockwise through arm 8 until the projection 14 slides over the stop 15 and the rack falls until the projection 14 engages the lower stop 17. At the half-hour, pin 2 releases arm 8 and the trip lever 6 rocks under gravity until held by the stop 6<1>, Fig. 3, the rack also being rocked until teeth formed thereon by pins 9 mesh with a wheel 10 in the motor drive and with the tail 11 of the hammer 12. The pitch of the pins 9 is a multiple of that of the teeth of wheel 10. One stroke is made as the rack is raised and as the projection 14 passes between the stop 15 and spring 16 it stresses the latter so that when the top of the stop 15 is reached the spring 16 rocks the rack out of mesh with wheel 10 to the position shown in Fig. 1. At the hour the hour-pin 3 rocks the arm 8 so that the projection 14 clears both stops 15, 17, and the rack falls until its arm 51 engages the hour snail 4, Fig. 4. When the pin 3 releases arm 8, the trip lever 6 rocks into engagement with the stop 6<1> bringing the rack into mesh with wheel 10 and the tail 11, striking being effected during return of the rack as above. When the electric motor 18, 19, Fig. 6, is used to wind the clock mainspring, overwinding is prevented by a brake 20, engaging the rotor 18, controlled by a conical travelling nut 21 actuated in known manner by the motor and also by the driven side of the mainspring. To ensure the motor running during striking an arm 24 rigid with the trip lever 6 is adapted to lift the brake arm 20 as the trip lever is rocked to bring the rack into mesh with its driving wheel. The arm 51 of the rack is provided, in known manner, with an elastic stop to prevent blocking of the snail should the current fail for a period including midday or midnight. For a large clock the motor may be controlled through a contact operated by means analogous to those for lifting lever 20 in Fig. 6.