US 3428879 A
Description (OCR text may contain errors)
Feb. 18, 1969 F. MARTI 3,428,879
OSCILLATOR DEVICE FOR TIMEPIECE MECHANISMS Filed Oct. '7, 1966 NVENTOR Fi /72 4/4,???
I] llllllHllH United States Patent 13,857/ 65 U.S. Cl. 318-128 9 Claims Int. Cl. H02]: 33/04 The present invention relates to oscillating timing and driving devices for timepiece mechanisms.
Electrically-operated timepieces using tuning forks or similar structures as timing and driving members are wellknown. Such prior art devices have been less than satisfactory for use in small timepieces such a watches due to the fact that the frequency of their oscillations varies greatly with changes in the position of the timepiece, and depends upon the construction of the timepiece housing and various other factors.
It is an object of the present invention to provide a timepiece oscillation device whose frequency is not readily disturbed by the factors described above, and which is simple, small and rugged in construction.
An oscillator constructed in accordance with the present invention includes two parallel torsion blades fastened rigidly at their ends to a single support member and arranged symmetrically with respect to the longitudinal axis of the support member. Secured to each torsion blade near its center is an arm which is provided at one of its ends with a magneto-electric vibrations-ustaining device, and at the other end with a counterweight. The two arms oscillate in opposite directions, and the entire assembly is shaped and constructed in a manner such that .at all times and regardless of the position of the mechanism, the torques on the torsion blades are of the same magnitude but are oppositely directed. Also, the torques are applied in the same plane or in parallel planes. As a result, substantially no torque is transmitted by the support member to the timepiece mechanism or its case.
The accompanying drawing shows in schematic form, two embodiments of the present invention:
FIGURE 1 is a plan view of the first embodiment;
FIGURE 2 is an elevation view of the structure shown in FIGURE 1;
FIGURE 3 is a partially cross-sectional view taken along line III-III of FIGURE 2;
FIGURE 4 is a schematic circuit diagram of a transistorized circuit for sustaining the oscillation of the oscillator device;
FIGURE 5 is a plan view of the second embodiment; and
FIGURE 6 is a partially cross-sectional structure shown in FIGURE 5 taken along line VIVI.
The oscillator device shown in FIGURES 1 to 4 includes two parallel torsion blades 1 and 2, each of the same length and fastened rigidly (e.g., welded) at its ends to a support member 3. The support member is fastened to a mounting plate 4 of a timepiece mechanism. The two torsion blades 1 and 2 are arranged in a single plane parallel to the plane of the support member 3. Alternatively, the blades also could be arranged in two mutually parallel planes. The blades 1 and 2 are arranged symmetrically with and parallel to the longitudinal axis of the central bar 3a of the support member 3.
The central bar 3a has two relatively narrow end portions 3b each of which is fastened to a post 5 or 6 which is secured to the plate 4. The central bar 3a has, near each of its ends 3b,.a bent arm 30 on one side and a U-shaped arm 3d on the other side. The bent arm 30 at one end is arranged on the same side of the central bar as the U-shaped arm 3d at the other end so that the points of attachment of the torsion blades 1 and 2 to the ends of the arms 30 and 3d are staggered longitudinally with respect to the transverse axis of the support member 3.
The arms 3c and 3d are bent in order to permit a certain amount of tension to be applied to the blade 1 at the time it is fastened onto the support member. This tension increases the resistance of the blade to bending, and also compensates for differences in temperature expansion between the blade and the support.
The two torsion blades 1 and 2 are flat, thin metallic blades each of which has a central portion 1a or 2a of a length approximately equal to half of the total length of the blade. Each of the central portions 1a and 2a is twisted so as to form an angle of with the remainder of the blade. This arrangement has the advantage of offering great resistance to longitudinal bending. The detailed features and advantages of this blade are more fully described in my copending US. patent application filed on the same date as this application and entitled Vibrator Device.
To the center of each torsion blade 1 and 2 there is fastened an oscillating arm 7 or 7'. At one end of each arm is an electromagnetic oscillation sustaining device and of the counterweight are located at the same distance from the axis of rotation of the arm to which they are secured. Also, the positions of the oscillation sustaining device 8 and the counterweight 9 with respect to the axes of oscillation of the arms 7 and 7' is opposite to to the corresponding positions of the oscillation sustaining device 8 and the counterweight 9.
Arms 7 and 7' are driven so as to oscillate in opposite directions. Thus, at all times and in all different positions, the elastic torques of the two torsion blades and the opposing mechanical torques of the two oscillating arms are oppositely directed, of the same magnitude, and are located in the same or parallel planes. Thus, all of these torques substantially cancel each other. Thus, the oscillator structure transmits very little if any force or vibration to the timepiece mechanism or its case. This very effectively prevents the timepiece mechanism from going into undesirable parasitic vibration, as sometimes happens in prior art devices. Furthermore, this balancing of forces prevents the loss of energy usually caused in prior art devices due to unwanted vibration of the timepiece mechanism and its case.
FIGURE 3 shows the details of construction of the oscillation sustaining device 8'. The other device 8 is identical to the device 8'. Oscillation sustaining device 8 includes a permanent magnet 10 fastened to the inside of a cylindrical case 11 which is open at the bottom. A coil 12 which has two separate windings B and B (see FIGURE 4) is wound on the upper end of a cylindrical member 13 which is secured to the plate 4.
As is shown in FIGURE 4, the four coils B and B are connected in a well-known transistorized oscillator circuit in which Tr is a transistor, C is a capacitor, B represents the signal windings, B represents the pulse windings, and S is a source of direct current. For the sake of simplicity, FIGURE 4 shows each of the windings B, and B as a single winding. Actually, each winding sh-own represents the two windings B or B of the separate oscillation sustaining devices 8 or 8' connected to one another in series. By means of this series interconnection, synchronization of the oscillations is maintained. This circuit operates in a known manner to move the magnet 10 and case 11 upwardly and downwardly in a timed cyclical movement so as to sustain the oscillation of the arms 7 and 7'.
An oscillating device in accordance with the present invention constitutes the regulating and driving device of the timepiece mechanism of which it is a part. The torsion blades replace the usual hairspring and the oscillating arms replace the usual balance wheel. More specifically, one arm 7 or 7 can be coupled mechanically to a ratchet mechanism in a known manner so that the oscillatory movement of the arm operates the ratchet which turns the hands the hands of the timepiece. A ratchet mechanism highly suitable for this purpose is described in my copending US. patent application filed on the same date as this patent application and entitled Ratchet Mechanism. Alternatively, two of such ratchet mechanisms can be used, with each coupled to a different one of the arms 7 and 7, and with appropriate gearing to drive the hands of the timepiece. The oscillator mechanism of the present invention can be used in many other known arrangements for regulating the operation of timepieces.
In order to eliminate the four welds used for attaching the torsion blades 1 and 2 to the support member 3, the support member and blades can be formed as a single unit.
In the embodiment shown in FIGURES 5 and 6, two flat torsion blades 21 and 22 are fastened to a rectangular frame 23 which has two transverse cross-members 23a fastened by means of screws 25 and posts 26 to a base plate 24 of a timepiece mechanism. The blades 21 and 22 are arranged parallel to one another in a single plane which is parallel to the plane of the supporting frame 23, and are arranged symmetrically with respect to the longitudinal axis of the frame. Each torsion blade supports an oscillating arm 27 or 27'. Each arm 27 or 27' has an electromagnetic oscillation sustaining device 28 or 28 at one end outside the frame 23, a counterweight 29, 29' at the other end inside the frame 23. The oscillating arm 27 passes through a slot in the counterweight 29, and the oscillating arm 27 similarly passes through a slot in the counterweight 29. The centers of gravity of the oscillation sustaining devices and the counterweights are at the same distance from the arm which supports them. The two arms 27 and 27 oscillate in opposite directions.
Each oscillation sustaining device 28 or 28' includes a permanent magnet fastened to a U-shaped part 30 rigidly connected to the oscillating arm and cooperating with a double-winding coil 31 wound inside a U-shaped support 32 fastened to the plate 24. The two windings of the coil 31 are connected in series in a transistorized circuit such as that shown in FIGURE 4, and the operation of the device shown in FIGURES 5 and 6 is substantially the same as that of the device shown in FIGURES 1 through 4.
In this embodiment torsion blades having twisted central portions like blades 1 and 2 can be used, and the two torsion blades and the support frame can be made integral, all within the scope of the present invention.
The above description of the invention is intended to be illustrative and not limiting. Various changes or modifications in the embodiments described may occur to those skilled in the art and these can be made without departing from the spirit or scope of the invention as set forth in the claims.
I claim: 7
1. In a timepiece, an oscillator device, said device comprising, in combination, at least one pair of elongated torsion fiexure members, a support member, said torsion flexure members being secured to said support member,
4 a pair of oscillation arms, each being secured to one of said fiexure members intermediate its ends and being aligned transversely to the longitudinal axis of the fiexure member to which it is secured, means for cyclically oscillating each of said arms about the longitudinal axis of the flexure member to which it is secured, the directions of oscillation being opposite at all times, said oscillating device being constructed with its parts arranged symmetrically with respect to a centerline in a plane containing both of said flexure members, and the torsion forces in one of said flexure members being equal and opposite to those in the other of said fiexure members.
2. Apparatus as in claim 1 including means for securing each of said torsion flcxure members to said support member, said securing mean comprising an elongated flexible member secured at one end to said support member and at its other end to one of said torsion flexure members adjacent one of its ends, said flexible member being aligned transversely with respect to said torsion fiexure member.
3. Apparatus as in claim 1 in which each of said torsion flexure members comprises a relatively thin strip of resilient material.
4. Apparatus as in claim 3 in Which each of said torsion flexure members has a central portion which is twisted angularly with respect to the plane of the remainder of said fiexure member.
5. Apparatus as in claim 1 in which said cyclical oscillating means comprises two magnets and two counterweights, with the magnets and counterweights arranged in opposing pairs, each secured to one end of one of said arms, the centers of gravity of each electromagnet and counterweight being located equidistant from the longitudinal axis of the arm to which they are attached.
6. Apparatus as in claim 2 in which said torsion fiexure members are staggered longitudinally with respect to one another.
7. Apparatus as in claim 1 in which said oscillation arms are aligned in a single plane substantially perpendicular to the plane in which said flexure members are located.
8. Apparatus as in claim 7 including two pairs each comprising a separate magnet and counterweight secured at opposite ends to one of said arms, the counterweights being positioned adjacent one another, each having a slot embracing the arm to which it is not attached.
9. Apparatus as in claim 5 including a pair of dualwinding coils, means for mounting each of said coils with the windings encircling one of said magnets with the magnet being free to move longitudinally within said coil, and a pair of transistorized electrical oscillator circuits each connected to one of said coils.
References Cited UNITED STATES PATENTS 3,277,643 10/1966 Favre 58-23 X 3,351,788 11/1967 Favre 31022 MILTON O. HIRSHFIELD, Primary Examiner.
D. F. DUGGAN, Assistant Examiner.
U.S. Cl. X.R.