GB782954A - Improvements in and relating to movements for electric timepieces - Google Patents

Abstract

782,954. Electric clocks and watches. ETABLISSEMENTS E. JAEGER. Aug. 29, 1955 [Sept. 2, 1954], No. 24767/55. Class 139 In an electric timepiece the oscillations of the balance staff 5, Fig. 34, are maintained by the interaction of a coil 3 carried by the staff and a magnetic field, the coil being carried by a non-metallic frame 4. The fixed permanent magnet 6 having poles 8, 9, Fig. 35, is associated with a similarly shaped soft iron plate 10, Fig. 34. The maintaining circuit is closed at each swing of the balance by a pin 12 which meets a flexible contact blade 14. The spindle 5 drives the gear train through lifts 17 and a pinion 18. The magnetic field may be produced by two rectangular magnets arranged as shown in Figs. 1 and 2 to allow the coil C to oscillate therebetween. Ring magnets may be used and if desired such magnets may be provided with soft iron pole pieces P<SP>3</SP>, P<SP>4</SP>, Fig. 10. When the invention is applied to watches the magnetic field is obtained from a permanent magnet formed by a broken ring A<SP>3</SP>, Fig. 21 having end poles of opposite polarity and carrying soft iron pole pieces P<SP>13</SP>, P<SP>23</SP>, Fig. 22a, which support the balance staff and between which oscillates the coil C, Fig. 21. The pole pieces may be angled as shown in Fig. 29a. In another embodiment the permanent magnet comprises a broken ring the ends of which constitute poles of the same polarity and which has an intermediate pole of opposite polarity. The similar poles Fig. 31 are interconnected by a soft iron pole piece P<SP>15</SP>. A soft iron member J extends from the intermediate pole and ends in a rectangular part P<SP>25</SP>which with pole piece P<SP>15</SP> serves to support the balance staff. The minute hand shaft passes through the hole T<SP>1</SP>. In another embodiment Figs. 33a, 33b the magnetic field is formed by two flat ring magnets A<SP>1</SP>c, A<SP>2</SP>c. The coil C oscillates between the pole pieces P<SP>17</SP>, P<SP>18</SP> and the rings are connected by a rod M. In the above embodiments the circuit closure means may comprise a pin g, Fig. 20, oscillating with the balance staff and on every swing meeting a rod Á projecting from a rotary insulating cylinder W carrying two contacts w' w<SP>2</SP> which co-operate with a resilient contact blade K<SP>2</SP>. The impulse is given to the balance as it passes through the equilibrium position. The magnetic field may be obtained from an electromagnet E of the kind shown in either Fig. 12 or Fig. 15. In the latter a yoke Q closes the magnetic circuit. The appropriate phase relationship between the current of the electromagnet coil and that of the oscillating coil is obtained by suitable capacitor and/or inductance circuits, Fig. 17-19 (not shown).