Balance of watches and method of its manufacture

• US 3,893,288 A
• Filed: 01/02/1974
• Issued: 07/08/1975
• Est. Priority Date: 01/20/1973
• Status: Expired due to Term

• Current Assignee: Heinz Meitinger
• Original Assignee: Heinz Meitinger
• Inventors: Meitinger, Heinz
• Primary Examiner(s): Jackmon, Edith Simmons
• Application Number:
  US05/429,583
• Time in Patent Office: 552 Days
• Field of Search: 58/28A,28B,107 310/36 331/154
• US Class Current: 368/169
• CPC Class Codes: G04B 17/063 Balance construction balances with frequency adjustment screw G04B18/006; balances with temperature compensation G04B17/222; balancing devices G04B17/28

Abstract

A watch balance assembly particularly suited for electrically driven watches and in which the balance carries coils contributing to the balance inertia with relatively great tolerances, a method for manufacture is suggested in which the balance comprises a shaft, an electrically insulating hub carrying the coils, and a metallic peripheral ring shrunk on to said hub and forming the junction of coil terminals clamped between the hub and the ring during the shrinking, the tolerances of the coils being compensated by removal of mass from said ring so as to inertia-balance the whole assembly with respect to said shaft.

Claims

1. A balance assembly for an electric watch comprising a shaft oscillatory about its axis, a hub member formed of an electrically insulating material rigidly connected to and symmetrical with said shaft, electromagnetic means mounted to said hub member and a metallic, electrically conducting ring member coaxial with said shaft and peripherally disposed about said hub member and in engaging retentive relationship therewith.

2. The balance assembly of claim 1 wherein said electromagnetic means comprises a coil having two terminal wires, one of said terminal wires being connected to the shaft and the other of said terminal wires being clamped between the hub member and the ring member.

3. The balance assembly of claim 1 wherein said electromagnetic means comprises two coils connected in series, each of said coils having two terminal wires, one of said terminal wires of each coil being connected to the shaft and the other of said terminal wires of each coil being clamped between the hub member and the ring member.

4. The balance assembly of claim 1 wherein said hub member is formed of a heat-settable plastic material.

5. A method of assembling a balance assembly of an electric watch, said balance assembly comprising an electrically insulated hub member, having electromagnetic means mounted thereon, said hub member being rigidly connected to and symmetrical with a shaft member, said hub member being disposed within and in retentive engagement with a peripheral, metallic, electrically conducting ring, said method comprising the steps of:

a. applying radially acting forces to said ring member to elastically deform the ring member to a generally oval shape;

b. positioning said hub member and associated shaft member within the area defined by said elastically deformed ring member, the shaft member being aligned perpendicular to the horizontal plane of the ring member;

c. removing said radially acting forces whereby said ring member returns to its circular shape and peripherally engages and retains said hub member; and

d. balancing said assembly by removing mass from the metallic ring to compensate for the contribution of the elements comprising the balance assembly to the moment of inertia thereof.

6. The method of claim 5 wherein said electromagnetic means mounted on said hub member comprises a coil having two terminal wires, said method including the further steps of connecting one of said terminal wires to the shaft and positioning the other of said terminal wires between the hub member and the ring member prior to removing the radially acting forces from said ring member, whereby upOn removal of said forces, said other terminal wire is clamped between the hub member and the ring member.

7. The method of claim 5 wherein said electromagnetic means mounted on said hub member comprises two coils connected in series, each of said coils having two terminal wires, said method comprising the further steps of connecting one of said terminal wires of each coil to the shaft and positioning the other of said terminal wires of each coil between the hub member and the ring member prior to removing the radially acting forces, whereby upon removal of said forces, said other terminal wires are clamped between the hub member and the ring member.