Mechanical oscillator for time-keeping devices

Claim 2

A mechanical oscillator adapted for use in time-keeping devices comprising: a pair of parallel adjacent flat resilient arms free of each other at one end, a connecting element integral with said arms and joining said arms together at the other end, said arms being coplanar in a first plane and being symmetrically disposed on opposite sides of a second plane disposed midway therebetween and perpendicular to said first plane, mass elements on the free ends of said arms, said arms and the mass elements thereon forming a pair of substantially identical partial oscillators adapted to oscillate in respectively opposite phase in the direction perpendicular to said first plane and at one and the same frequency whereby the oscillation centers of said arms and said mass elements lie in said first plane during resting of oscillation and at least one of said mass elements has a hollow shape relative to its oscillation center, said other mass element being freely movable into the hollow shape in oscillation direction, each said mass element having the center of oscillation thereof so disposed on the opposite side of said second plane from the center of oscillation of the respective arm that the torque exerted by each arm about the line of intersection of said first and second planes is compensated by the torque exerted by the respective mass element about said line when the arm members and mass elements oscillate.

Claim 3

A mechanical oscillator adapted for use in time-keeping devices comprising: a pair of parallel adjacent flat resilient arms free of each other at one end, a connecting element integral with said arms and joining said arms together at the other end, said arms being coplanar in a first plane and being symmetrically disposed on opposite sides of a second plane disposed midway therebetween and perpendicular to said first plane, mass elements on the free ends of said arms, said arms and the mass elements thereon forming a pair of substantially identical partial oscillators adapted to oscillate in a respectively opposite phase in a direction perpendicular to said first plane and at one and the same frequency, each said mass element having the center of oscillation thereof so disposed on the opposite side of said second plane from the center of oscillation of the respective arm that the torque exerted by each arm about the line of intersection of said first and second planes is compensated by the torque exerted by the respective mass element about said line when the arm members and mass element oscillate, first means at the free ends of said arms for maintaining said arms in oscillation and second means at the free ends of said arms for imparting driving force to a driver element, said first means including first permanent magnet means connected to the free end of one of said arms, said second means comprising second permanent magnet means connected to the free end of one of said arms on the other side of the oscillator, said permanent magnet means establishing a magnetic field transverse to the direction of oscillation of said arms, each of said first and second permanent magnet means being mounted on a sheet metal part of ferromagnetic material shaped to form a return path for the magnetic field thereof, said sheet metal parts forming at least a portion of the mass elements for said arms, said first magnet means being cylindrical with its axis extending in the direction of oscillation of said arms, said second magnet means being in the form of spaced magnEt elements adapted to receive the driven element therebetween.

Claim 4

A mechanical oscillator adapted for use in time-keeping devices comprising: a pair of parallel adjacent flat resilient arms free of each other at one end, a connecting element integral with said arms and joining said arms together at the other end, said arms being coplanar in a first plane and being symmetrically disposed on opposite sides of a second plane disposed midway therebetween and perpendicular to said first plane, mass elements on the free ends of said arms, said arms and the mass elements thereon forming a pair of substantially identical partial oscillators adapted to oscillate in a respectively opposite phase in a direction perpendicular to said first plane and at one and the same frequency, each said mass element having the center of oscillation thereof so disposed on the opposite side of said second plane from the center of oscillation of the respective arm that the torque exerted by each arm about the line of intersection of said first and second planes is compensated by the torque exerted by the respective mass element about said line when the arm members and mass element oscillate, first means at the free ends of said arms for maintaining said arms in oscillation and second means at the free ends of said arms for imparting driving force to a driver element, said first means including first permanent magnet means connected to the free end of one of said arms, said second means comprising second permanent magnet means connected to the free end of one of said arms on the other side of the oscillator, said permanent magnet means establishing a magnetic field transverse to the direction of oscillation of said arms, each of said first and second permanent magnet means being mounted on a sheet metal part of ferromagnetic material shaped to form a return path for the magnetic field thereof, said sheet metal parts forming at least a portion of the mass elements for said arms, said first magnet means being cylindrical with its axis extending in the direction of oscillation of said arms, said second magnet means being in the form of spaced magnEt elements adapted to receive the driven element therebetween.

Claim 5

A mechanical oscillator according to claim 2, in which said spaced magnet elements taper inwardly toward each other at their adjacent ends.

Claim 6

A mechanical oscillator according to claim 2, in which both of said permanent magnet means are mounted on the free end of a single one of said arms.

Claim 7

A mechanical oscillator according to claim 2, in which said first and second permanent magnet means are mounted on respective ones of said arms.

Claim 8

A mechanical oscillator according to claim 4, in which the mass element for the other of said arms is in the form of a sheet metal part of nonferromagnetic material.

Claim 9

A mechanical oscillator according to claim 6, in which said sheet metal part of nonferromagnetic material is substantially U-shaped with the legs thereof extending in the direction of oscillation of the arms, the said leg on the opposite side of said second plane from the respective arm being heavier than the other one of said legs.