US3602842A

US3602842A - Electromechanical oscillator including a dual vibrator for producing a bent frequency

Info

Publication number: US3602842A
Application number: US848553A
Authority: US
Inventors: Scudder Smith
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-08-08
Filing date: 1969-08-08
Publication date: 1971-08-31
Anticipated expiration: 1988-08-31

Abstract

A member whose expansion and elastic properties are minimally affected by temperature, such as invar, is caused to longitudinally vibrate at its fundamental frequency, at a harmonic frequency, or at two frequency modes simultaneously. The vibrations induce corresponding pulses of the two frequencies in tuned circuits to effect a low frequency beat note usable to drive a mechanical output such as a ratchet and pawl for chronometric purposes. A beat frequency of optimum utility is achieved by altering the natural frequencies so that the various harmonics are not exact multiples of the fundamental said alteration being achieved by making the vibratory member nonuniform in section, unit mass, or composition of matter per unit length. A single vibratory member in which two frequencies are generated maintains a constant relationship therebetween despite temperature changes.

Description

United States Patent [72] Inventor [21 Appl. No. [22] Filed [45] Patented [54] "ELECTROMECHANICAL OSCILLATOR INCLUDING A DUAL VIBRATOR FOR PRODUCING A BENT FREQUENCY 154, 156, 157; 310/25; 3l8/l28; 84/405,456; 525 25, 23 AO, 25V

[56] Referenos Cited UNITED STATES PATENTS 3,150,337 9/1964 Allison 331/116MX WEIGHT 3,382,459 5/1968 Asten Primary ExaminerRoy Lake Assistant Examiner-Siegfried H. Grimm AtlorneyAlbert M. Zalkind ABSTRACT: A member whose expansion and elastic proper ties are minimally affected by temperature, such as invar, is caused to longitudinally vibrate at its fundamental frequency, at a harmonic frequency, or at two frequency modes simultaneously. The vibrations induce corresponding pulses of the two frequencies in tuned circuits to effect a low frequency beat note usable to drive a mechanical output such as a ratchet and pawl for chronometric purposes. A beat frequency of optimum utility is achieved by altering the natural frequencies so that the various harmonics are not exact multiples of the fundamental said alteration being achieved by making the vibratory member nonuniform in section, unit mass, or composition of matter per unit length. A single vibratory member in which two frequencies are generated maintains a constant relationship therebetween despite temperature changes.

.SEIVSDR v1 Ra'fonv 8 Rap ECHANICHL CONVERTER ELECTROMECHANICAL OSCILLATOR INCLUDING A DUAL VIBRATOR FOR PRODUCING A BENT FREQUENCY fundamental and a harmonic or they may be two harmonics.

The beating together of the fundamental frequency and a harmonic or a frequency derived from a harmonic or the beat- 'ing together of two harmonics, or frequencies derived therefrom can be made to produce a substantially lower beat frequency than either one separately. This beat frequency can be used for actuating chronometric devices by an electromechanical drive.

' Ordinarily the beating of a fundamental and a higher order a harmonic might produce a beat too high in frequency to be usable for practical mechanical conversion or might yield no heat at all. However, by altering the physical properties of a suitable vibratory member such as a rod vibrating longitudinally, harmonics producible will not be exact multiples but in fact may vary by sufficiently small incremental amounts of cycles per second to provide a low beat frequency between the two modes chosen for actuation of mechanisms of known types such as a pawl and ratchet or a synchronous motor.

The invention utilizes circuitry and solenoid means for effecting longitudinal vibrations of a fundamental and a third harmonic in a rod shaped to alter the frequencies so that the harmonic is not an exact multiple of the fundamental, but having a difference frequency of a minimum order. The circuitry also senses and electronically amplifies these altered frequency vibrations in the rod to effect a beat utilized to drive a chronometric device. In other forms of the invention dual rods in an X" or H shape are used; each rod being vibrated at the same harmonic mode preferably the first harmonic which are the respective fundamentals. The difference frequency is utilized for chronometric purposes.

In the drawing FIG. 1 is a functional block diagram of the system of the invention; FIG. 2a is a diagram of the mechanical and electrical essentials of a single rod form of the invention; FIG. 2b shows a modification of FIG. 2a; and FIGS. 3 and 4 show dual rod forms of the invention in H and X" formation, respectively.

Referring to FIG. 1, the circuitry is shown by block diagram in a generally symbolic illustration of the invention for purposes of basic explanation.

A vibratory member consisting, for example, of an invar bar or rod is carried at its center point by a rigid clamping col- .lar which will understood to be fixed to ground.

Frequency altering masses integrally connected to or part of the rod and located substantially at the rod ends adjust longitudinal vibrations of the fundamental and a harmonic so feeding electric impulses to circuitry approximately tuned to respective frequencies F and F" which are natural compressive vibratory frequency modes of the rod. Incorporated in the common output of amplifying

means

36 and 36" is a mixer means effecting a chronometric drive 40 within which is developed'current of relatively low beat frequency derived from F and F. Drive 40 may comprise a solenoid which actuates a mechanical converter device 42 responsive only to the beat frequency.

For example, a mechanical converter device comprising a tuned reed responsive to a certain frequency or a vibratory armature and spring, all symbolized by the reference character 42 can be utilized to operate a ratchet wheel via a double pawl. Such devices are within the skill of the art and, in fact, one well-known pawl and ratchet wheel arrangement for watches is operated by a tuning fork coupled to a double-acting pawl. In the present invention a solenoid in series with drive coils 25, later described in circuitry would actuate the pawl arrangement.

Ordinarily, the output of the vibratory rod drive 30 is alternating current and consists, according to my findings based on experiment, of a wave having the frequency of the altered third harmonic modulated by the difference between the altered third harmonic and three times the altered fundamental. Thus, this modulated output wave is the beat frequency which actuates the pawl arrangement 42.

By way of an actual example, an altered third harmonic of 41,919 cycles per second and an altered fundamental of 13,871 cycles per second were used and the beat frequency developed by the invention was found to be 306 cycles per second. This experimental result was checked on other apparatus and found to be correct. Further, by using the above described arithmetical relationship l have been able to predict the value of beat frequencies knowing the values of the altered fundamental and third harmonic. Thus, the altering of the frequencies is significant, since if, an exact multiple of the fundamental and third harmonic were used, the beat would be zero.

The beat frequency achieved by my invention is, of course, of a very low magnitude and therefore practical for operating mechanical devices.

If desired, the output can be rectified resulting in pulsating direct current and in such case an ordinary iron armature in the mechanism 42 would be believed suitable. Otherwise, the armature of such mechanism 42 would require a nonhysteresis material. Also, a synchronous motor could utilize the output of the beat frequency either with alternating or direct pulsating current, wherein the number of poles of the motor determines its speed in accordance with well known principles.

The currents of a fundamental and a third harmonic frequency, F and F", also pass through red drive means 30, circuitry comprising solenoids 25. It may be noted that in addition to F and F" the low beat frequency also exists in the drive solenoids 25. However, since the rod has no natural vibratory frequency mode at the beat frequency there is no effect on the rod due to the beat frequency in solenoids 25.

For each frequency the sensor and drive means and the rod itself may be considered as a single closed feedback loop with conditions proper to generate and sustain the respective vibratory mode of the rod, by virtue of the actual vibration of the rod feeding back from the drive means to the sensor means.

Common to both loops is the mixer means 40 for utilizing the beat frequency for chronometer drive.

Thus, a vibratory system consists of a mass factor, a stiffness factor, and a viscosity factor, the frequency being primarily dependent on mass and stiffness factors. The members 20 change the mass factor of both the fundamental and harmonic frequencies but in different relative proportional degree making possible a beat frequency between these vibratory modes.

It is believed that in addition to invar, a ceramic, or quartz rod or tube could be used since they have low temperature coefficients of expansion and other physical properties such as elasticity, being highly elastic in response to longitudinal vibrations. The vibrations can be induced electromagnetically, by piezoelectric effect, or by electrostatic means.

The invention takes advantage of the phenomenon caused by weighting the vibratory member at both ends, where it consists of a single rod, the ends being the antinodes of all natural vibrational frequency modes namely the points at which maximum longitudinal amplitude of vibration occurs.

As noted elsewhere in this disclosure, it has been found that best results'are obtained by utilizing an altered fundamental and an altered third harmonic. The use of even harmonics such as the second, etc., is believed impractical from a constructional standpoint, because an even harmonic would have an antinode at the center of the rod where it is preferred to support the rod. Such support preferably being rigid, would contribute unwanted variations in frequency and would lessen vibrational amplitude and sensor response, particularly since the antinode is the optimum point for sensor response. It is believed that the best place to support a longitudinally vibrational rod is at a single node of the fundamental and a harmonic; the use of an evenharmonic would require support at two nodes for structural symmetry. This would cause problems due to temperature changes and the compressive stresses in the rod occasioned thereby as well as unpredictably effecting frequency of vibration. Odd numbered harmonics are more practical because they have a node at the rod center where support is believed desirable and coincides with the node of the fundamental. The most desirable odd harmonic is the third, not only for the fact that it is of strong amplitude, but it is the lowest odd harmonic and thus yields the lowest beat frequency. Also, the use of the third harmonic simplifies the physical characteristics of vibration means such as electromagnetic solenoids, and of sensor means, e.g., pickup coils since the nodes and antinodes of the third harmonic have a simpler relationship than would be the case for higher order odd harmonics.

Further, dual vibrations in a rod of a fundamental and an even, e.g., a second harmonic produce interference in physical vibratory motion within the rod because of a lack of spatial symmetry between the direction of motion of antinodes of the vibrations. However, where an altered fundamental and altered third harmonic are induced in a rod supported at its center, antinodes occur at the ends of the rod as they do for any harmonic and its fundamental, and the node at the center of the rod is the same node for both the altered fundamental and the altered third harmonic, or for that matter any odd numbered harmonic. Thus the simplest support point is obtained and vibrational interference lowered considerably.

To the best available knowledge at the present time, a single rod embodiment utilizing an altered fundamental and altered third harmonic is preferred in an arrangement as described above, and is described in more detail below.

Other types of vibratory member structures are believed usable. Thus, a pair of integral rods in an array, supported at the intersection, and each rod resonated by vibratory drive means at the same vibratory node preferably its fundamental. One rod would be altered as by weighted ends, or would be of a different length as compared with the other, so that the rods could produce a beat frequency ofa very low order. Rods in a H array are also thought usable.

A particular feature of the invention is the fact that whether a single rod is used as a vibratory member or integral rods in a X or H configuration, temperature changes will not seriously effect the accuracy of the beat output because the integral construction will minimize frequency change when caused by temperature change. Thus, the temperature change will be the same for the fundamental and the harmonic in a single rod type of vibratory member and will tend to be the same for both rods in an integral dual rod construction. However, in the X or H type there may be a greater effect on frequency of one rod as compared with the other, and it is believed that this can be compensated for by making one rod ofa slightly different temperature coefficient of expansion or elasticity as compared with the other. The same can also be done, if necessary, for portions of a single rod for the purpose of maintaining a constant relative vibrational frequency change of the fundamental or altered fundamental therein as compared to harmonic or altered harmonic. For example, suppose a temperature change has a different proportionate effect on the third harmonic than on the fundamental. The third harmonic has three nodes and four antinodes as compared to one node and two antinodes for the fundamental. By adding or subtracting mass at the extra antinodes of the third harmonic or by strengthening or weakening or changing the chemical composition around the extra nodes of the third harmonic or by otherwise changing the rod at sensitive points it is thought possible to compensate out virtually all change of the beat frequency due to temperature or other physical causes.

In an actual working model now to be described certain changes were made which were discovered to enhance the strength of sensor pickup and reference is made to FIG. 20 for this purpose. Thus, in FIG. 2a the invention is modified as compared with the description of FIG. I in order to take full advantage of the known points of the occurrence of nodes and antinodes of a longitudinal vibratory bar or rod. In FIG. 2a (and later in FIG. 2b) the same reference numerals are used as in FIG. 1 for like parts.

Referring to FIG. 2a, a rod 10, for example, of invar is magnetized and can be mounted at its center indicated by the node plane or point 48 which has suitable rigid support provided, e.g., by a support ring 15 of the kind shown in FIG. 1. The node point 48 is the node point for both the fundamental and the third harmonic.

The ends of the rod are provided with weights enlargements corresponding to the weights 20 of FIG. 1. In this instance, the proper points for the weights using the term point in a generalized sense, is at the antinodes 52 for the natural fundamental, which would be at the rod ends in any event. The directional arrows indicate the direction of vibration longitudinally of the rod wherein the arrows are identified as to the fundamental and third harmonic on FIG. 2a for antinodes 52.

The additional antinode arrows for the third harmonic at 55 in two locations are indicated as being in opposite direction at the locations shown. There are no other antinodes for the fundamental; with each half cycle of vibration the direction of movement simply reverses with respect to the center node 48 and the rod ends. The same reversal of movement occurs at each half cycle of vibration for the third harmonic with two additional nodes 58 for the third harmonic.

Encompassing the central portion of the rod is a component of the drive means, comprising coil 25 having a portion understood to be on each side of the center support. A sensor or pickup coil 35 for the fundamental frequency is located at or near the third harmonic left node point 58. The pickup coil 35" for the third harmonic is located at or near antinode 52, at the right end of the rod.

The purpose of this differential location of the pickup coils is to minimize pickup of third harmonic vibration by the coil 35, and to maximize pickup of the harmonic vibration by the coil 35".

In order to provide a magnetic field within and emanating from the rod, a pair of permanent elongated horseshoe type magnets are used. Thus at each side of the rod are magnets 60 and 60' the north poles of 60 and 60' facing each other and similarly the south poles. This arrangement provides for magnetic fields entering and leaving the rod from the sides where there is little tendency to add any tension thereto that might interfere with longitudinal vibration, and it has been found, as a matter of practicality, despite vibration in the rod the magnetic field is not anchored by the stationary magnets, but has the effect of moving with the rod vibration so as to inductively effect a voltage in the pickup coils.

It is thought that the magnetic field in and emanating from the rod is actually a summated composite of the fields of the individual atoms, molecules, or aggregates within the rod. Thus even though these small rod magnets may be induced magnets, they still move with the rod vibration and hence the summated internal field also moves with the rod vibration. In any event, it has been demonstrated beyond doubt that the arrangement is completely operative and that optimum positioning of the permanent magnet poles for maximum induced voltages is a relatively simple matter for strengthening coil pickup and would, of course, depend on the parameters of any particular arrangement such as dimensions of rod, distance of pickup coils from the drive coil, magnet strength, etc.

In this connection it should be noted that the rod itself could be made of permanent magnetic material and magnetized or carry magnetic collars within the pickup coils. In fact, experimentation indicates that many expedients could be used. For example, electromagnets instead of permanent magnets could be used. Whether the rod has permanent or nonpermanent magnetic material it has been thought desirable to provide a permanent magnetic field from nonvibrating members such as 60 and 60 to preclude lessening of the rod magnetic field due to jostling of the atoms, molecules and aggregates by the high frequencies employed.

Preferably, and as described above, the drive coil and the pickup coils should be located to have maximum reaction with respect to antinode regions of motion to which they are to respond and the pickup coils should preferably be separated from the drive coil sufficiently to avoid feedback oscillations in'the circuits not usable for vibrating the rod.

The coil 35' and capacitor C1 is a circuit approximately tuned at the natural fundamental frequency of rod 10, transistor T1 being an amplifier, whence the combination effects oscillations in the drive coil and rod of the fundamental frequency.

Similarly coil 35" and capacitor C4 are approximately tuned to the third harmonic'and together with transistor T2 effect third harmonic oscillations of drive coil and rod.

The desirability of approximate tuning is twofold. Firstly the amplitude of current and voltage from the pickup coil is increased for the desired frequency. Secondly, and more importantly the phase relationship is correct for the desired frequency and out of phase for the other frequency making possible simultaneous but independent inducement of both frequency modes of oscillation. Except for the fact that the 35 '-Cl combination is out of phase for the third harmonic and the (435" combination is out of phase for the fundamental the rod and circuit would tend to favor one or the other frequency and the rod would vibrate only at this favored frequency.

In operation, battery 63 is connected at its negative terminal to the emitters of transistors T1 and T2 and at its positive terminal to drive coil 25 with a solenoid 65 in series for actuating pawl mechanism 42. A capacitor C shunts, if need be, solenoid 65 to bypass the third harmonic and fundamental, depending on design of the circuitry.

The other end of drive coil 25 connects to both collectors of the transistors for energization thereof.

Pickup coil 35' and capacitor C1 form an oscillatory circuit approximately tuned to the fundamental vibrating frequency of rod 10. Hence, an oscillation at the fundamental will produce a maximum AC voltage across C1. This voltage in turn results in an input current to the base of transistor TI via capacitor C2 which appears in amplified form in drive coil 25. Furthermore, substantially the same action occurs at transistor T2 for third harmonic feed to drive coil 25, wherein pickup coil 35 and capacitor C4 effect the oscillatory circuit for approximately the third harmonic frequency and input to the base is via capacitor C3.

The tuning of the oscillatory circuits is not critical and can vary as much as ten percent or more from optimum. The important factor is to phase the drive coil 25 so that it effects maximum force in phase with the instantaneous direction of vibratory motion of rod for each frequency. By virtue of the mechanical vibration of the rod properly phased feedback is induced in the pickup coils to sustain the desired oscillatory frequencies.

Referring to the beat frequency of 306 cycles heretofore mentioned, the apparatus used to produce such frequency comprised an invar rod 6 inches long, having a diameter of 0.211 inches, except at the ends where the diameters were 0.278 inches for a distance of one-fourth inch in from each end. Center mounting was rigid, using an arcuate array of three equally spaced (l apart) pointed screws projecting into a small peripheral groove around the rod. The drive coil used had an estimated 2,000 turns of wire (0.007 inch diameter) and a resistance DCof 56 ohms. Inside diameter was inch, outside diameter inch, and length /8 inch of coil on each side of the center suspension of the rod.

The pickup coils were each of 1,000 turns (estimated), %inch I.D.; inch O.D., 5/16 inch long; 33 ohms DC 5 strand wire of 0.0022 inch diameter each strand.

The permanent magnets 60 and 60' were each Alnico. This was believed preferable to magnetizing the rod 10 since vibration of the rod could cause loss of magnetic strength which might make operation of the circuit erratic.

The transistors were each 2N2924 NPN and:

C1 0.05 mfd.

C2 0.33 mfd.

C4 0.02 mfd.

C3 0. l mfd.

It will be understood that phasing is, of course, important and persons skilled in the art will recognize that proper connections from the pickup coils are necessary for proper input phasing to the transistors as well as proper connections from the transistors to the drive coil.

Referring to FIG. 2b the identical rod, pickup and drive coils are utilized the only change being in circuitry to the extent that the beat frequency is isolated and amplified by means of a diode rectifier and transistor. Thus,'all parameters heretofore described in connection with FIG. 2a are the same and will not be described repetitively. However, in FIG. 2b a diode 70 connects from the collectors of transistors T1 and T2 through resistor 73 and capacitor 76 to a transistor T3. A capacitor 79 shunts the cathode of diode 70 to the negative of the battery. The positive terminal of the battery connects to the collector of T3 through pawl activating solenoid 65. The emitter of T3 connects to battery negative.

In operation a beat frequency current from the collectors of T] and T2 is rectified at the diode and pulsating direct current passes via resistor 73 and capacitor 76 to T3 where it is amplified before going to the pawl operating solenoid 65.

Capacitor 79 is of a value to have a high impedance for beat frequency but a low impedance for the fundamental and third harmonic frequencies; in effect it is a filter for the higher frequencies in order to expedite measurement of the beat frequency.

Resistor 73 and capacitor 76 combine to limit current to T3 so as to minimize current drain from drive coil 25.

Referring to FIG. 3 a formation of rods in the configuration of the letter H is illustrated wherein the crossbar will be understood to be rigidly fixed. The emitters of transistors and 1 l1 connect tothe negative of the battery designated by a ground symbol. Transistor 110 has its base connected to

pickup coils

112 and 113 via a capacitor 114. The base of transistor 11] connects to

pickup coils

115 and 116 via the capacitor 117. The positive terminal of the battery connects through solenoid 65, which drives pawl mechanism 42, to the drive coils 120 and 121 of the left hand rod and also to the drive coils 123 and 124 of the right hand rod. The drive coils are connected via ground to the battery negative.

The phantom bracket associated with each rod symbolizes the

magnets

60 and 60 as heretofore explained in connection with FIGS. 2a and 2b. Without going into structural detail, it may be mentioned at this point that the magnets are so constructed, preferably, that the rods can pass through apertures in the magnetic poles in order to avoid distortion effects which might otherwise take place due to the strong magnetic field being unbalanced on one side of each rod.

From the above description it will be apparent that the pickup coils are at the rod centers while the drive coils are at the rod ends, this being a reversal of the previously described arrangements. Such illustration is given for reversal merely to show, as has been determined experimentally, that it is possible to do so. Preferably, it is believed that the drive coil should be at the rod centers with the pickup coils at or toward the ends suitably disposed, all as heretofore described, so that the pickup coils are at an optimum position to sense as much vibrational amplitude change as possible for the frequency used which can be a fundamental or a harmonic, preferably an odd harmonic.

It will be apparent that with a dual rod construction as shown in FIG. 3 there need not be enlargement of the rod ends and therefore the pickup coils (although shown at the center in FIG. 3) could be placed at the rod ends and closer thereto than would be the case where the rod ends require enlarged portions which take up space with single rod embodiments as shown in FIGS. 2a and 2b.

In FIG. 3 the rods are presumably of different length, although this is not apparent from the drawing since it is believed that such length difference would be very small. The difference in length provides the difference in frequencies. The oscillatory circuit for each rod is tuned approximately for the fundamental of that rod. Accordingly, the beat frequency results from the difference between fundamentals. However, it is believed quite possible to have each rod vibrated at harmonies of the same mode. Such harmonics should, according to my investigations, be odd harmonics. Thus, third harmonics characteristic of the length of each rod are believed usable.

From the above description, it will be apparent that the drive coils of each rod are connected in parallel as are the pickup coils. Accordingly, assuming identical positioning on each rod of the pickup coils, and of the drive coils, in a symmetrical array, both the driving and the pickup effect is augmented since obviously twice the energy can be imparted to or derived from each rod. Of course, care must be given to proper phasing of the coils by way of correct connections as will be understood by persons skilled in the art.

The symmetry of coil placement provides for dynamic balance in energy transfer into or out of the rods.

The operation of the form shown in FIG. 3 is substantially the same in principle as heretofore described in that the tuned circuit comprising transistor 110, capacitor 114 and

pickup coils

112 and 113 maintain fundamental frequency (or an odd harmonic) longitudinal vibration in the rod via drive coils 120 and 121 with feedback through the rod by virtue of its longitudinal vibration, such feedback manifesting itself in the pickup coils and stabilizing the oscillatory circuits.

The identical action takes place for the right hand rod via the pickup and drive coils in conjunction with transistor 111 and capacitor 117, it being, of course, understood that the same mode of vibration is used as in the left hand rod, that is, either a fundamental or an odd harmonic, with a slight difference in frequencies between the two rods. Mixing of the frequencies picked up by the pickup coils then occurs due to the common connection 130 and the beat frequency passes through solenoid 65 to actuate the mechanism 42.

The identical arrangement as just described for FIG. 3 is fragmentarily illustrated in FIG. 4 and since all circuitry and operation is the same there is no need for repetition. However, FIG. 4 difiers from FIG. 3 to the extent that the rods are in an X" shape being rigidly secured at the central area. For purposes of orientation of FIG. 4 with FIG. 3 all pickup and drive coils have been illustrated on the rods, corresponding precisely to the same coils having the same reference characters as in FIG. 3.

The angle between the rods of FIG. 4 can be of any convenient value, although for symmetry a 90 angle may be preferred, which is thought would minimize vibratory interaction.

It will be obvious to persons skilled in the art that various changes may be made within the teaching of the principles discussed hereinabove. For example, in the forms of the invention shown in FIGS. 3 and 4, the rods may be of the same length but varying as to one or more other factors to effect a difference in frequency as well as to compensate each other for changes in temperature or other extraneous influences so that although their frequencies are affected the beat frequency remains the same.

By virtue of the integral construction of the vibratory means, whether one or two rods, it is believed that there is substantial compensation under conditions of temperature variation so that while the values of the two frequencies may change, the changes will compensate to the net result of little or no change in beat frequency. Further, the invention is thought inherently capable of design to diminutive size for use in watches and personally carried timepieces; the electronics, using transistors as oscillators and amplifiers for both frequencies, are already translatable to extremely small size in the present state of development of the art. The physical vibration of the vibratory means as a feedback path is thought particularly novel in the application used for chronometric purposes. The use of a single drive coil as part of the drive means for the several purposes of imparting both fundamental and third harmonic energy to the rod structure, and also as a recipient of the beat frequency, which can be derived by connection to the drive coil, is believed to be a novel and highly advantageous feature.

Finally, the combination of the various components, while intended primarily for chronometric purposes, is not thought limited thereto but may, in fact, be usable in other applications where the particular effects possible with the invention are found pertinent.

Iclaim:

1. An electromechanical oscillator device comprising a vibratory means capable of physical vibration at two detectable frequencies, drive means for effecting vibration in said vibratory means, detecting means for detecting respective vibrational frequencies in said vibratory means; mixing means for mixing the detected frequencies to produce a beat frequency usable for chronometric purposes.

2. A device as set forth in claim 1, wherein said vibratory means is elongated and the vibration therein is longitudinal.

3. A device as set forth in claim 1, wherein said vibratory means has elongation and vibration occurs longitudinally in the direction of elongation.

4. A device as set forth in claim 1, wherein said drive means comprises electromagnetic coil means at a substantially central area of said vibratory means.

5. A device as set forth in claim 1, wherein said drive means comprises electromagnetic coils disposed adjacent respective ends of said vibratory means, said latter means comprising an elongated member.

6. A device as set forth in claim 1, said vibratory means comprising a single rod and support means rigidly supporting said rod substantially at its center.

7. A device as set forth in claim 1, wherein said vibratory means comprises a pair of integrally connected rods having a generally central area and rigid support means substantially at said central area.

8. A device as set forth in claim 7, wherein said rods are substantially parallel, and said vibratory means also includes a crossbar connecting said rods, wherein said vibratory means is supported on said crossbar.

9. A device as set forth in claim 7, wherein said vibratory means comprises a pair of rods disposed angularly to each other and being supported at the intersection thereof.

10. A device as set forth in claim 1, wherein said vibratory means is comprised of magnetic material and means to alter the vibratory frequencies for the natural fundamental frequency and for a selected harmonic of said vibratory means.

11. A device as set forth in claim 1, said vibratory means comprising magnetic rodlike means, said drive means comprising electromagnetic coil means encompassing said rodlike means and said frequency detecting means comprising respective magnetic induction sensors responsive to longitudinal vibration in said rodlike means.

12. A device as set forth in claim 1, wherein said vibratory means comprises a rod structure and said drive means being operative to effect longitudinal vibration therein at two frequencies, said frequency detecting means being approximately tuned to respond to respective frequencies and being disposed at respective ends of said structure.

13. A device as set forth in claim 12, said frequencies being in the general relationship of a fundamental and a third harmonic.

14. A device as set forth in claim 1, wherein said vibratory means comprises a pair of integrally connected rodlike means arrayed in a symmetrical geometric configuration, and said drive means comprises. a respective vibration effecting device for each said rodlike means whereby each said rodlike means vibrates longitudinally at a respective frequency, to effect frequencies to which said frequency detecting means is responsive.

15. A device as set forth in claim 14, wherein each rod vibrates at a respective fundamental frequency.

16. A device as set forth in claim 14, wherein each rod vibrates at a respective odd harmonic of the same mode.

17. A device of the kind as set forth in claim 1, said vibratorymeans comprising a member having a mass means thereon for altering the frequency of vibration therein for the fundamental and third harmonic to minimize the frequency of the beat frequency.

18. A device as set forth in claim 1, said vibratory means comprising a member having means to alter at least one said vibratory frequency so that said frequencies are not multiples of each other.

19. A device as set forth in claim 1, including means whereby both said frequencies are altered so as not to be multiples of each other.

20. A device as set-forth in claim 1, said vibratory means comprising a vibratory member, said detecting, mixing, and drive means comprising electronic circuitry; said drive means effecting oscillating flux operative to vibrate said vibratory member at said frequencies, and means whereby said circuitry effects feedback by vibration of said vibrating member to maintain the oscillation.

21. A device as set forth in claim 1, wherein one said frequency is approximately the fundamental and the other said frequency is approximately the third harmonic of said vibratory means, and means whereby said frequencies are not multiples of each other.

22. A device as set forth in claim 1, said vibratory means being a member of nonuniform physical characteristics so as to effect vibratory frequencies which are not multiples of each other.

23. A device of the kind set forth in claim 1, including means for effecting mechanical motion from said beat frequency at a mechanical rate proportional thereto.

24. A device as set forth in claim 1, said vibratory means comprising magnetic material having a magnetic flux therein; said drive means comprising solenoid means energizable to effect vibration of said vibratory means at said two frequencies; said detecting means comprising solenoid means disposed to sense said vibrations at said two frequencies responsive to vibratory motion of the vibratory means.

25. A device as set forth in claim 24, including permanent magnet means to effect said magnetic flux in said vibratory means.

26. A device as set forth in claim 24, wherein said vibratory means comprises a rodlike member; said drive means solenoid means being disposed at a node of one of the frequencies of vibration; said detecting means solenoid means being disposed in proximity to respective antinodes of vibration of said two frequencies.

27. A device as set forth in claim 24, including oscillatory electronic circuits comprising all said solenoid means; said circuits being tuned to the approximate value of respective frequencies; wherein the physical vibration of said vibratory means transfers energy from said drive means solenoid means to said detecting means solenoid means to effect feedback for maintaining oscillation of said respective circuits.

28. A device as set forth in claim 27, wherein said drive means solenoid means is common to both said circuits for receiving oscillatory output; and a solenoid connected to said drive means solenoid means for actuating a mechanical device at a rate proportional to said beat frequency.

Claims

14. A device as set forth in claim 1, wherein said vibratory means comprises a pair of integrally connected rodlike means arrayed in a symmetrical geometric configuration, and said drive means comprises a respective vibration effecting device for each said rodlike means whereby each said rodlike means vibrates longitudinally at a respective frequency, to effect frequencies to which said frequency detecting means is responsive.

17. A device of the kind as set forth in claim 1, said vibratory means comprising a member having a mass means thereon for altering the frequenCy of vibration therein for the fundamental and third harmonic to minimize the frequency of the beat frequency.

20. A device as set forth in claim 1, said vibratory means comprising a vibratory member, said detecting, mixing, and drive means comprising electronic circuitry; said drive means effecting oscillating flux operative to vibrate said vibratory member at said frequencies, and means whereby said circuitry effects feedback by vibration of said vibrating member to maintain the oscillation.