Patent GB-421348-A (GB)
Title: Improvements in clockwork movements
IPC: G04C3/06
Filed: 1933-07-21
Abstract: 421,348. Electric clocks. DELVINIOTTI, J., 12, Rue Reynouard, Paris. July 21, 1933, No. 20615. [Class 139] In a clock or watch movement having an electrically - maintained balance, the balance 2 is non- magnetic and carries a magnetic mass 25, two stationary coils 13, 13<a>, have their polepieces 12, 12<a>, in the same plane as the balance, and contact means 17<a>, 19<a>, 18<a>, 20, operatively connected with the balance, open the circuit of the coils, when the magnetic mass is symmetrically positioned with respect to the two polepieces. The mass 25 may be of soft iron or a permanent magnet. The balance staff 10 carries a collar 19 formed with two contact cams 19<a>, 19<b> which coact with the end 17<a> of an arm 17 which is carried by an insulated pillar 16 and has a flexible contact blade 18 for contacting with a fixed insulated stud 20. Figs. 3 and 5 show plan and elevation of the balance and underneath are developments of collar 19. As the balance swings in the direction of the arrow, the end 17<a> meets cam 19a and rides up the latter until blade 18 has been raised sufficiently to close contacts 18<a>, 20. This gives a circuit from source of current through the clockwork mechanism and 19, 19<a>, 17<a>, 17, 18, 18<a>, 20, 13, 13<a> to source of current. The energized coils 13, 13<a>, attract the mass 25. By the time this mass is symmetric with the poles 12, 12<a> (Fig. 5) the end 17<a> has dropped off cam 19<a> and opened the circuit at 17<a>, 19<a>, and 18<a>, 20. Subsequently cam 19<b> rides over end 17<a>, depressing it further. On the return swing cam 19<b> raises arms 17<a>, 17 and 18 to close the circuit, so that the coils 13, 13<a> are energized in both directions of swing of the balance. One cam 19<a> or 19<b> may, however, be omitted. The balance drives the motionwork to the hands by means of a disc 11 on the balance staff 10, Fig. 8. A pawl 26 pivoted at 29 to disc 11 is controlled by spring 27 and has a pin 9 for driving ratchet 4: retrograde movement is prevented by pawl 28. The staff of ratchet 4 has a worm 5, Fig. 1, or a pinion for driving the motionwork. Various modifications of the circuit contacts are illustrated and described in the Specification. In some, the cams 19<a>, 19<b> merely raise and lower the arm 17 and do not act as electric contacts. In the modification of Fig. 18, the contact 18<a> and arm 18 are omitted and the stud 20 contacts with the end 17<a> of arm 17 and is carried on an arm 20<a> controlled by a spring 20<b>. The arm 17 is held between two blades 17b, 17<c>. In the construction of Fig. 20, contact is made in one direction of swing only. The pawl 26 drives the ratchet 4, as in Fig. 8, but the circuit is made between a contact 28<a> on the retrograde pawl 28 and a contact 29<a> on a spring-controlled arm 29. The relation of pawl 28 to the teeth of wheel 4 is such that the circuit is open when the magnetic mass on the balance is symmetrically positioned relatively to the polepieces. In the modification of Fig. 21, a pin 37 rigid with the balance staff 10 comes down on to a blade 38 riveted at 38<a> on to a spring-controlled lever 35. As the lever 35 rotates clockwise about its pivot 35<a> it makes the circuit between its contact 39 and a contact 40 on a spring-controlled lever 36, which latter at the same time is rocked clockwise about its pivot 36<a> so that its pawl 45 drives the ratchet 4 to the motionwork. On the return swing lever 35 is held by its stop 43 and pin 37 flexes and wipes past the blade 38. There may be two or more balances on the one staff, each balance having a pair of coils allotted thereto. In the construction of Figs. 13 and 14 the invention is applied to watches. The magnetic mass 5 on the balance 3 coacts with co-planar poles 4, 4<a> of two coils 6, 6<a>. Contact for the circuit of these coils is made between the end 7<a> of a blade 7 and cams 8, 8<a> on the balance staff 15, the undersides of the cams being covered with insulation.