Patent GB-287182-A (GB)
Title: Improvements in or relating to electric clocks
IPC: G04C3/06
Filed: 1928-03-17
Abstract: 287,182. Conrad, F. March 17, 1927, [Convention date]. Electric clocks; balances and pendulums, regulating electrically; actuation by condensers; framework and going trains; motionwork.-In a clock in which the balance is electrically maintained in oscillation by electromagnets which act magnetically and directly on the balance wheel, the latter is of magnetic material and has poles to which the impulses are applied. The curbpins used to adjust the effective length of the balance spring serve also as the contacts of the circuit, these latter alternately making contact with the balance spring in the to and fro oscillations of the latter, thereby completing the circuit of the magnets and charging and discharging a condenser. The balance staff, Fig. 1, carries a balance spring 2 anchored at 3, a balance wheel 5 having upright flanges 6, 7 and cut-out portions 8, 9, and members 17, 18 of opposite screw thread and extending partially round the staff 1. The ends 48, 51, 52, 53 of the flanges 6 and 7 coact magnetically with the poles 13, 14 of the magnets 11, 12. The curb-pins 40, 41 are adapted to close the electric circuit through the spring 2; as it expands this spring meets contact 40 and closes the circuit, energizing the magnets and charging the condenser 44. At this instant the poles 48, 52 are slightly nearer the poles 13, 14 than are the poles 51, 53 so that the magnets add to the oscillation of the balance in the same direction. When the spring contracts it touches contact 41 and discharges the condenser through the magnets, again giving an impulse to the balance, but this time in the reverse direction. The condenser also prevents sparking at the contacts 40, 41. At the oscillations of the staff 1 the members 17, 18 alternately engage the wheel 21 so that the latter always rotates in the same direction; this wheel 21 drives shaft 22, worm 23, wheel 24, shaft 25, wheels 26, 27 and shaft 28, the other end 31 of which bears the minute hand. A wheel 32 on this shaft 38 drives the hour hand by wheel 33, shaft 34, and wheels 35, 36; wheel 36 being rigid with a sleeve 37 which is loose on shaft 28 and carries the hour hand. When the hands are adjusted on their spindles the worm 23, being irreversible, prevents motion being transmitted backwards to interfere with the balance mechanism. Figs. 3, 7, and 8 show a practical construction in which the gearing for the hands, is contained independently between frame plates 61, 62, Fig. 7, and the remainder of the mechanism is between plates 70, 72, Fig. 8. Fig. 3 shows the assembly with the plates 70, 72 attached to plate 61 so that the wheel 24, Fig. 7, correctly engages the worm 23, Fig. 8. In another construction of clock, Figs. 17 and 18, balance mechanism 182, 185, 184 includes a magnetic or armature portion 186 which coacts with two coils 180, 181. In this case the contacts 194, 195 are rigid and the contact 193 on the balance staff is resilient, being carried by an auxiliary spring 191. The Specification as open to inspection under Sect 91 (3) (a) describes also the following apparatus. Modifications of the members 17, 18 on the staff 1 are shown in which (1) these members have grooves 90, Fig. 9 (Cancelled), and inclined faces 91, 92 to actuate the teeth of the wheel 21, and (2) the members have offset ends 95, Fig. 11 (Cancelled), to actuate the wheel 21. When either member 17 or 18 is actuating the wheel the teeth of the latter pass freely through the gap in the other member. In another construction of clock, Fig. 13, (Cancelled), a pendulum 128 carries a magnet 136 which coacts with a fixed coil 138, the circuit being closed alternately by a member 148 on the pendulum at contact spring blades 157, 158 so that the condenser 106 is charged and discharged alternately, the coil 138 thereby giving an impulse to the pendulum in each direction of swing. At the same time a coil 124 is energized to operate pawl mechanism 104 which drives the motionwork 116. This subject-matter does not appear in the Specification as accepted. Specification 296,031 is referred to.