US1769988A

US1769988A - Synchronizing apparatus

Info

Publication number: US1769988A
Application number: US166083A
Authority: US
Inventors: Arthur P Davis
Original assignee: Individual
Current assignee: Individual
Priority date: 1927-02-05
Filing date: 1927-02-05
Publication date: 1930-07-08
Anticipated expiration: 1947-07-08

Description

Jgly s, 1930. A, R DMS 1,769,988

SYNCHRONI Z ING APPARATUS Filed Feb. 5. 1927 7\ lNvENToR IMQIDMI #is ATTORNEYS Patented July 8, 1930 PATENT OFI-Ica y .ARTHUR IP. DAVIS, F NEW YORK, N. Y.

sirNcHRoNIzINGfl APPABT'US v AApplication led February 5, 1927. Serial No. 166,083.

This invention relates to a systemfor automatically comparing the frequencies of sounds emitted periodically from a p1ural-.

ity of dierent sources, and more particularc 5 ly concerns ja system for comparing frequencies of the'beats of a watch, clock or other time piece to the frequency of the 'beats of a standard or substantially accurate time piece of the same type. f All time pieces of a given type are usually constructed from identical parts, but-'because of slight variations in the physical properties of the materials used, as well as variations in assembling thesel parts, vthere is l5 frequently a marked variation between the speed of .operation of -time pieces so constructed.v @O

4After being assembled, time piecesl are usually compared with a standard time 'ece,

that is, one which runs accurately at standard time, andare adjusted `until they run approximately at thesame rate as does the standard time piecefrFhis adjustment is usually accomplishedl'by observing tli/e 25 movement of the hands, and this type .of

comparison must continue over an extended perlod of time 1f accurate results are to be obtained, acomparison lasting twenty-four;-

hours 4or more being necessary to obtain an ordinary degree -of accuracy. In the manufacture of watches4 and certain other time pieces, it is customary to construct al]I9 of a given'type of. such instruments to give a predetermined number of beats per minute when adjusted to standard time.

Thus a comparison between the rateofooperg ation of a standard watch and a watch to be adjusted may be 'obtained by comparing the frequencies ofthe beatsthereof. As most watches are'constructed to run at the rate of about three hundred beats per minute, it is obviouslyl impossible, from a practical standpoint, to accurately cmpare the beats methods. l

Withthe above and other considerations in mind, it is an'object of the present inven tion to 4provide asystem by means of which the beats of'a plurality of watches or other time pieces may be very quickly and acof watchesfdirectly by ordinary physical.

curately compared and, moreo specifically it is proposed to provide a stem of this nature including a device whlch directly indicates which of two watches is running at the higher rate, and also 'ves a direct in- 55 dication of the diii'erence etween the rates of operation of the two watches.

Itisfa further object of the present invention to rovide a s stem including means for ampli ying the eats of the watches being compared, so that these beats `may operate suitable indicating means. Other specific objects, advantages and characteristic features of the present invention will become apparent as the description thereof progresses. l

In describing the invention in detail, reference will be" made to the accompanying ratus of the present invention; and

Fig. 1 is a simplified and diagrammatic showing of the frequency compang apparatus of the present invention; and

Fig. 2 is a sectional view of a modied form of means for responding to the beats of the watches being compared.

Referring to the drawing, and more particularly to Fig. 1, the apparatus of the present invention comprises, in general, two microphones'or other sound responsive devices M and for responding to the beats of the watch s being com ared, two amplifying devices A and A or amplifying the electrical impulses produced in the microphones, and an indicating 'instrument S responsive to the output currents of-the tvgo, amplifiers, for indicating directly the differenceD in `speed of operation of the two watches and also indicating which of the Y two watches is operating at the higher speed.

The sound orn vibration responsive devices M and M and the ampliiers A. and A have been sh wn `as microphones and vacuum amplifie respectively in the preferred embodiment of the invention illustrated. It should be-elearly understood, however, that other forms of responsive devices and other forms of amplifiers, such as. mechanical amplifiers of the relay, tuned reed or other type, might be yused without departing from the scope of the invention disclosed.`

The sound responsive devicesLM and M may take any one of a number'mf suitable forms, and in the embodiment shown, comrises microphones of the well known type 1n which the resistance of an electric circuit is varied 'by'sound impulses impressed on a diaphragm. The micro hones M and M are connected respective y to the pri'- -mary windings -2 and 2 of two transformers T and T through circuits including the battery v3, these circuits being tuned. to resonance a't substantially the frequency of the beats of the watches by means of they condensers 4 and 4. The circuit for the microphone M ma be traced as follows z-from the microp one M, wires 5 and 6, primary winding 2 of transformer T,

wires

7, 8, 9, and 11, battery 3, andwires 12, 13, 14,15 and 016 tothe micro hone M. The circult for the microphone follows :-from the microphone M', wires 17 and 18, primary winding 2 of transformer v T', `wires-19, 20, 10 and 11, battery 3.and

wires 12, 13, 14,'15`an'd 21 to the microphone M.

The` transformers T and T may take any suitable form, and are preferably of the iron -core type, having any suitable or desi-red ratio of voltage transformation. u The input circuits of the 'transformers T and T are rather broadly tuned by the

condensers

4 and 4, so. that these circuits are particularly sensitive to a band of frequencies representing the usual variations from standard beat frequency ordinarily encountered in watches that have not been regulated. 'l

In the vacuum tube amplifier of the disclosed embodiment of the invention, the

secondary windings

22 and 22 of the transformers T and T are directl connected respectively tothe input or grid-filament circuits of two vacuum tubes V and V of the well known three element type. The

filaments

23 and 23 of the vacuum tubes V and V are heated by'currents from the battery 3 throughcircuits which are obvious from the drawing, and the plate circuits of these tubes rare connected through-a plate battery 24'to the armature and field windings respectively of the indicating instrument S as hereinafter described. The plate circuit of the vacuum tube V is preferably connected in series with the primary winding of a transformer T of any suitable form, and the ield Windings of the instrument S are connected with the secondary winding 66 of this transformer as hereinafter described, and in this manner an alternating current is impressed on these field windings. It should be understood 4that a transformer may also be included in "i the plate circuit of the tube V which supplies energy to the armature winding of the instrument S, or the plate circuits ofboth of the tubes V and V may be connected directly to may^be traced as found preferable.

The indicating instrument S may take any suitable form, but is .preferably of the form generally known as a synchroscope, that is,

an instrument having arotary armature element whichl indicates, by its speed of rotation, the difference in the frequency between two alternatin or pulsating currents impressed respective y on its field 'and armature windings, and also indicates, by the direction of rotation of the armature, which current has the higher frequency. In the embodiment shown, the instrument S includes a rotor or armature 25 comprising a pivotally mounted shaft 26 of soft iron or other suitable magnetic material, surrounded by a stationaryl armature coil orvwinding 27, and carrying two oppositely disposed sector shaped vanes 28 and 29 at the ends thereof as shown. The shaft 26 is journalled in suitable bearings carried by a frame, not shown, and a pointer 30is fixed to one end of the shaft and arranged to move in close proximity to a stationary circular scale 31, a section of which -has been shown in the drawing. The scale is preferably provided with graduations 32, and with oppositely directed

arrows

33 and 34, the arrows being designated by suitable distinctive indicia and acting to designate the significance of the direction of rotation ofthe pointer 30.

The field structure of fthe instrument S comprises a plurality of spaced field windings, and as shown, each pair of diametrically

opposite windings

35, 36 and 37, 38 is connected in series and these two pairsare also connected in multi le. A condenser 39 is connected in series with the windings 37 and 38 and acts to maintain a phasedisplacement between the currents fiowing in the two pairs of windings. d

The plate circuit of the vacuum tube'V is connected iu series with the. armature winding 25 through a circuit which may be traced as follows z-from plate 40 of the tube V, wire 41, armature winding 27,

wires

42, 67 and 68, plate battery 24 and wires 45, 13, 14 and 46 to the filament 23 of the `vacuum tube V. The plate circuit of the vacuum tube V is connected to the primary winding of the transformer T" through a circuit which maybe traced as follows from the plate 40( of the vacuum tube V', wire 69, primary winding 65 of transformer T", wires 70 and 68, plate battery 24 and wires 45, 13 and 54 to the filament 23 of vacuum tube V. The secondary winding 66 is connected with the field windings of the instrument S through a circuitwhich may be traced as follows from the winding 66, rwire 47, divided through two parallel paths, one of which comprises field winding 35, wire 48, field winding 36 and

wires

49 and 43, and the other of which comprises wire 50, condenser 39,

.wire 51,1-1e1d winding 3s, wire 52,5e1d winding 37 and wire 53, thence through wire 44, tof

the secondary winding 66 of the transformer T.

I n the operation of the apparatus described, two watches or other time pieces W and W are placed in close proximity in microphones M and M respectively, these watches being preferably supported by the mouthpiece of the microphone as shown. One of these watches, say the watch W', is a standard watch, that is, a watch which has:

M or M, the beats are transmitted to thev microphone mechanism bythe resultant mechanical vibration of the mouthpiece as well as by sound waves, and hence appreciable variations of current are readily obtainable in the microphone circuits. i

The current variations in the primary circuits of the transformers T and T are amplified by these transformers and by the The frequencies of these plate currents correspond to the beat frequencies of the watches W and W respectively, and these plate currents are impressed respectively on the armature and field windings of the instrument S, the plate current from the tube V being converted from pulsating to alternating current in the transformer T. The alternating current in the secondary circuit of the transformer T produces a rotating magnetic field in the instrument S due to the phase displacement produced by the condenser 39, and, unless the frequency of the plate current from the tube V flowing in the armature winding 27 is of exactly the same frequency as the iield current, thearmature 25 will rotate Ain one direction or another, due to the magnetic reactions between the field and the armature. The armature rotates in one direction if the field current is of the higher frequency and in the opposite direction if the armature current is of the higher frequency, and in this manner the direction of rotation of the armature and its associated pointer .30 indicates whether the watch W under test is running faster or slower than the standard .es watch lV. Also, the speed at which the ar- `mature 25 and the pointer 30 rotate depends upon the difference between the'eld and armature frequencies of the instrument S and so gives an indicationof the difference in speed of operation of the two watches.

As soon as the two watches are placed on the microphones, the comparison between their respective speeds of operation is obtained, and the watch W under test may be regulated to increase or decrease its speed according to. whether the instrument S has indicated that this watch is running faster or slower. than the standard watch W. After regulation, the watch W is again compared to the watch W as before, the speed and direction of rotation ofthe armature 25 and its associated pointer 30 directly indieatingV the accuracy with which the. watch W under test has been adjusted. If the watch W has been adjusted to run at exactly the same rate as the 'standard watch W', the armature 25 remains stationary. It is not ordinarily necessary, however, to obtain an absolutely accurate adjustment of the watch under test, the adjustment being suiicient for practical purposes if the armature 25 and the pointer 30 move at a very low rate of speed. y'

Where the beat of the watch is very light,

so that very little sound is emitted thereby, 9

or where it is desired to obtain comparatively large current variations in the microphone circuits, a modified form of microphone as shown in Fig. 2 may be employed. This modified microphone includes the usual variable resisting element 60, connected with a diaphragm 61, 'a rod 62 being rigidly secured to the diaphragm 61 and the element 60, and extendingoutwardly to a point substantially in alignment with the outer edges of the mouthpiece 63. When a watch W is placed upon the mouthpiece of a diaphragm Lof this form, the rod 62 is engaged by the case of the watch, and vibrations due to the beats of the watch are eliiciently transmitted to the variable resistance element through this rod.

Obviously, the frequency comparing apparatus of the present invention has many very desirable features. By the use of this apparatus, the rate of operation of two Watches may be accurately compared` in a very short` period of time, less than a minute being consumed making such a comparison. The instrument S quickly and accurately indicates not only the differences in speed between the two watches, but also, which of the watches is operating at the higher -rate of speed. Thus, in adjusting awatch, it is not necessary to employ cut and try methods, as the operator is immediately informed as to whether the watch under test is running too slowly or too rapidly, and has a general indication of just how much too slowly or rapidly such watch is running. The apparatus of the resent invention is very simple and rugged 1n its construction, embodying only one moving element. The operation of the apparatus of the present invention is also extremely simple, and does not require the services of a skilled or specially trained operator.

Although the frequency comparing apparatus of the present invention has been-described in connection with certain specific elements and combinations, it should be clearly understood that the invention is not limited in its' scope to the exactl details or combinations' disclosed. For example, means other than microphones'may be employed for responding to the beats of the watches, and

other forms of amplifying means besides the vacuum tube amplifiers ihown might be used.

The indicating instrument might take any V one of a number of suitable forms and manyother changes, modications and omissions might be made without departing from the scope of the invention as defined by the appended claims. n

I claim:

1. Apparatus for comparing the frequencies of periodic vibrations from a. plurality of different sources comprising means responsive to said vibrations, and an indicating device controlledby said means for directly indicating which of said frequencies. is the higher and for giving a direct indication of 4 the differencebetween said frequencies.

2. Apparatus for comparing two series lof impulses from independent sources comprising separate means responsive to the impulses from eachsource, means-for amplifying the impulses received bysaid first means from each source, anda singleindicating device, responsive to said twoseriesiof amplified impulses, for indicating the ""'instantaneous difference in frequency between the two series of impulses vand for indicating which series has the higher frequency.

3. Apparatusfor comparing two separate series of impulses from independent sources comprising separate means, each responsive to one of said series of impulses, for varying 'electric currents in accordance with the fre- `quencles of saldimpulses, and a single electro-responsive device, operated by the simultaneous application of said electric currents thereto, for directly indicating the difierence in frequency between said two series of impulses and for directly indicating which series has the higher frequency.

4. Apparatus for comparing two separate series of impulses from independent sources comprislng separate means, each responsive to-.one of said series of impulses, for varying electric currents in accordance with the frequencles of said lmpulses, means for separately amplifying said electric currents, and a'slnglc electro-responsive device operated by the, simultaneous differential effect of said electric currents thereto, and havinga single vmeans for separately amplifying said electric currents, and a single movable' element 4responsive to'said two amplified currents for simultaneouslyindicating the difference in frequency between the vibrations from said devices and which of the vibrations has the higher frequency.

6. Apparatus for comparing the speed of operation of two mechanical devices comprising separate means responsive severally to periodic vibrations of said devices, said means varying electric currents in accordance with the frequencies of said vibrations, two audion tube amplifiers for separateqy amplifying said currents, and a single movable elementv responsive to said two amplified currents for simultaneously indicating the difference in frequency between the pediodic vibrations fromsaid devices and which of said vibrations has the higher frequency.

7. Apparatus for comparing the speed of operation of two mechanical devices comprising two separate electric control means re.- sponsive severally to periodic vibrations produced by the operation of said devices, said control means acting respectively to vary the currents in two electric circuits in accordance with the frequencies of said periodic vibrations, a rotary electro-magnetic indicating device having a field winding and an armature winding, and means for connecting said two electric circuits respectively to said armature and eld windings, whereby the speed of rotation of said indicating device gives an indication of the difference between the speedsofsaid two mechanical devices and the direction lof rotation of said indicating device indicateswhich of said mechanical devices is operating at the higher speed.

8. Apparatus for comparing the operation ,of two watches comprising separate means responsive severally to the beats of the incassa varied respeetivel by said microphones in accordance with t e frequencies of the beats -of said watches, two al" ion tube amplifiers having their input circ ts connected respectively to said two microphone circuits and means operated by the differential effect of the output currentsl of said ampliers for showing which of the watches is running at the higher rate of speed and for indicating the diii'erence in speed of the watches.

11. Apparatus for comparing the operation of two watches comprising separate means responsive severally to the beats of said watches, and an indicating instrument controlled by said separate means for indicating which of the watches isoperating at the higher rate.

12. Apparatus for comparing the operation of two watches. comprising separate means responsive severally to the beats of said watches, said means actingto vary two electric currents in accordance with the frequencies of said beats, and an indicating de-A vice ]ointly controlled by said currents for the other when one or the other of said watches is operating at the higher speed.

. 15.v Apparatus for comparingthe operation of two watches comprising two microphones each connected in a separate tuned circuit including a source of electric current, each of said microphones having means for engaging a watch and vibrating a resistance varying element in accordance with the beats of the watch, whereby the currents-in the two tuned circuits are varied respectively in accordance with the speed at which the two watches are operated, andan indicating instrument controlled by the saidcurrents for indicating the diiference in rate of operation of said watches and which of said watches is operating at the higher rate.

16. Apparatus for comparmg the operation of two watches comprising two microl phones each connected in a separate-tuned circuit including a source of electric current,

each of said microphones having means for engaging a watch case and vibrating a resist-yv ance varying element 1n accordance with the Y beats of the watch, whereby the currents in the two tuned circuits are varied respectively in accordance with the speed at which the two watches are operated, means for separately' amplifying said currents, and a rotary indicating instrument operated by said currents and acting to directly indicate the difference in rate of operation of said watches.

In testimony whereof I affix my signature.

ARTHUR P. DAVIS.

directly indicating which of said two watches is operating at the highe-speed.

13. Apparatus for c'o paring the operation of two watches'comprising separate means responsive respectively to the beats of said watches, and acting to vary two eleC- tric currents in accordnace with the frequencies of said beats, means for amplifying said currents and a rotary device operated by the differential eiect of said currents for indicating, by its direction of rotation which of sid watches is operating at the 'higher spee 14. Apparatus for comparing the operation of two watches comprising two microphones responsive respectively to the beats` of the watches and acting to vary electric currents in accordance with the frequencies of said beats, means for separately amplifying said varying currents, a rotary indicating device having a plurality of field windfied currents being supplied to said field 'A windings and said armature winding respectively, andfinean's for producing a phase displacement between the currents in certain of said Veld windings, whereby said rotary device is caused to rotate in one direction or CERTIFICATE or coRREcTIoN.

Patent No'. 1,169,988. 1 Granted July s, 1930, im E ARTHUR Pl DAVIS.

` It ishereby certifiedl that error appears in tlIOe printed specification ofthe above numbered patent requiring-correction as follows: Page 1, strike out present line 69, insert instead the words "drawing,. in which"; page 4, line 89,

claim 6, for the misspelled Word 'separateqy" read separately; 'page 5, line 42, claim 13, for "respectively" read severally; line 43, for "and" read said mean; .fand line 44, for the misspelled word "accordnace" read accordance; and that the `said Letters Patent should be read with these corrections therein that the san'Ie may conform to the lrecord of the case in the Patent Office.' Signed and sealed this 9th day of September, A. D. 1930.

. M. J.I Moore, (Seal) Acting Commissioner of Patents.