US2784586A - Watch timer - Google Patents

Description

March 12, 1957 M. c. CAMPBELL, sR., ETAL WATCH TIMER 3 Sheets-Sheet 1 Filed Sept. 25, 1953 ZeZZ Q1- aw v aez J7? March 12, 1957 M. c. CAMPBELL, sR., ETAL 6 WATCH TIMER Filed Sept. 25, 1953 3 Sheets-Sheet 2 IN VEN TOR5 March 12, 1957 M. c. CAMPBELL, sR., ET AL 2,784,586

WATCH TIMER 5 Sheets-Sheet 5 INVENTOR-S. 4% 6' @gafiell Filed Sept. 25. 1953 electronic watch timers.

United States Patent C WATCH TIMER Milton C. Campbell, Sr., and Milton C. Campbell, J r., Villa Park, Ill.

Application September 25, 1953, Serial No. 382,275

Claims. (Cl. 73--6) This invention is concerned generally with apparatus for testing watches, and more particularly with apparatus for affording a substantially instantaneous check of the time rate of watches.

Throughout the history of the watch and clock making art it has been necessary to time a watch against a standard timepiece for a period ranging from one day to several days in order to ascertain the accuracy of the watch. If the time rate of the watch is found by this method to be too greatly in error, further adjustment and timing of the watch is necessary. Thus, it may take several days, or even weeks, to adjust and time a watch by this time-honored method. This method is unsatisfactory in that the customer is deprived of his watch for too long a period and in that most watches will not run long enough to allow a jeweler to time them by this method if the jeweler is out of his shop for the weekend.

Various electronic timers for watches heretofore have.

been proposed for timing watches substantially instantaneously, actually in amatter of a few minutes. These prior electronic timers have utilized special frequency standards and generally have made printed records. Furthermore, they often have required considerable skill on the part of the jeweler for satisfactory operation.

Such electronic watch timers have been quite expensive, due at least in part to the expense of the frequency standard and to the expense of the printing mechanism. The use of such prior electronic watch timing apparatus thus has been economically justifiable only by large scale watch repair organizations. The only way independent repairmen have been able to time watches has been by the time-honored method of timing them for a day or two against'a standard clock.

It accordingly is an object of this invention to provide an electronic watch timer of simpler and more economical construction than any heretofore known in the art.

A further object of this invention is to provide an electronic watch timer aifording the jeweler or repair man on indication only, as distinguished from the permanent record of the prior art. t

More specifically, it is an object of this invention t provide an electronic watch timer having auditory or visual indications requiring no special interpretive skill on the part of the jeweler or repair man.

It has been common practice in the prior art, as heretofore noted, to provide special frequency standards in In most localities of the United States such frequency standards are superfluous. 'Although a single generator may tend to vary somewhat in frequency over short periods with changing loads, the

same is not true when a plurality of generators is connected to a common electrical distribution system. In

most areas of the United States, particularly those with large concentrations of industry or population, greater quantities of electricity are used than can be furnished from a single generator. Accordingly, a plurality of generators is utilized to supply the same electrical distribu- I tionsystem. Furthermore, pluralities of distribution sys- 2,784,586 Patented Mar. 12, 1957 tems covering different areas are often interconnected to effect the most efiicient supplying of power, and to prevent interruption of electrical service in the event of a power plant failure. If any one generator of several supplying a system or interconnected systems tends to depart from its nominal 60 cycle per second, it starts to act at least in part as a motor, and its operation is maintained at 60 cycles per second by the remainder of the distribution system including all of the generators connected thereto. The chances of all of a plurality of generators departing from 60 cycles per second in the same manner and at the same time are so negligible as to be unworthy of consideration. Accordingly, the power supplies in all but themost remote locality may 'be relied upon to remain extremely constant at 60 cycles per second without any variation even of a transitory nature.

(This, of course, excepts those few areas having power supplies operating at frequencies other than 60 cycles per second.)

Most watches operate with five beats per second, and the apparatus herein disclosed is designed for use with such watches. The apparatus could be modified to operate with other watches, but approximately nine out of ten watches operate at five beats per second, and the others are rapidly becoming obsolete. Accordingly, such modifications are not treated herein.

It is a further object of this invention to provide a watch timing apparatus utilizing a commercial power line as a frequency standard. A further object of this invention is to provide a Watchtiming apparatus utilizing a readily available electrical clock motor as a part of the comparing mechanism.

A further object of this invention is to provide novel means for relatively adjusting the phase of a frequency standard and of a watch being tested.

More specifically, it is an object of this invention to utilize a clock motor and rotary switch operated thereby for timing a watch, and to adjust the relative phase of the switch and watch by rocking the clock motor.

A further object of this invention is to provide an electronic watch timing apparatus utilizing a crystal phonograph pick-up for detecting watch beats.

It is a further object of this invention to provide, in an electronic watch timing apparatus, an. amplifier positively preventing feed-back.

Other and further-objects and advantages of the present invention will be apparent from the following description when taken in connection with the accompanying drawings wherein:

Fig. 1 is a perspective view of a watch timing apparatus constructed in accordance with theprinciples of the invention;

Fig. 2 is a vertical longitudinal sectional view of the pick-up unit;

Fig. 3 is a vertical cross-sectional view taken along the line 3-3 of Fig. 2;

Fig. 4 is a view on an enlarged scale showing the bottom of the pickup unit in cross section;

Fig. 5 is a side elevation, partially in section, showing the frequency standard;

Fig. 6 is a cross-sectional view along the line 6-46 of Fig. 5 showing the input connections to the frequency standard;

Fig. 7 is a rear end view of the frequency standard unit;

Fig. 8 is a view of the dial for indicating the accuracy of a watch being tested; and

Fig. 9 is a schematic view illustrating the electrical circuit of the apparatus including the amplifier.

Referring first to Fig. 1 for a general understanding of the invention, there will be seen a Watch timing apparatus indicatedgenerally by the numeral 24). This apparatus includes a chassis 22 having a top surface or table 24 on which is mounted a pick-up unit 26. A housing 28 having an inclined front panel 30 is mounted on the chassis and contains a frequency standard unit 32 having connected therewith a dial 34 indicating the number of minutes per day a watch being tested is fast or slow. The housing 28 also contains a loudspeaker 36 and suitable knobs 38 for turning the apparatus on and off, for controlling the volume of the apparatus, and for testing the operation of the apparatus before timing a watch. The case also is provided with a jack 49 for plugging in an ear phone for critical listening to a watch for determining the operation thereof without checking the time rate of the watch.

The pick-up unit 26 is shown more particularly in Figs. 2 and 3 and includes an inverted, substantially U-shapcd bracket 42 having outwardly directed feet 44 through which screws 46, conveniently sheet metal screws, are passed to mount the bracket on the upper surface or table 24 of the chassis 22. The upper end of the bracket 42 is apertured for receipt of a rubber grommet 48 which slidably and rotatably receives a pivot rod 50. Another rubber grommet 52 fits into the table of the chassis and bracket 56 are apertured'for the receipt of aligned rubber grommets 58 which tightly grip a pivot rod or axle 69.

A pair of rubber grommets 62 are loosely mounted on the outer ends of the rod or axle 60 and fit in aligned apertures of the depending arms of a third U-shaped bracket 64 pivotally to mount this bracket on the rod or axle 60. The last mentioned U-shaped bracket 64 is provided'at its front edge with 21 depending flange 66 through which is passed a screw 68. The screw 68 is threaded into a metallic sleeve 70 which is tightly gripped in a rubber tube 72. A similar sleeve 74 is gripped within the opposite end of the rubber tube 72 and is spaced from the sleeve 70.

A rectangular, box-like sheet metal pick-up housing 76 is secured to the sleeve by a screw 78 passing through one end of. the pick-up housing and threaded into the sleeve 74. A conventional crystal phonograph pick-up 30 is mounted in the pick-up housing '76 by any suitable means. It will be understood that pick-up elements other than a crystal could be used, but the crystal is preferred as it is inexpensive and readily available, and generates a relatively high voltage, whereas many other pick-ups,

such as electromagnetic pickups, do not generate very high voltages and might react unfavorably on a watch. Specifically, a magnetic pick-up might tend to magnetize a watch with resultin unsatisfactory operation of the watch.

A pick-up finger 82 is mounted in place of the usual phonograph stylus and comprises a stiff metallic rod having a bend in it at 84. A plastic cup 36 having a conical central cavity 88 as best seen in Fig. 4 is fixed on the bottom of the finger. A pedestal 90 (Fig. 1) is mounted on the table 24 and is topped by a foam. rubber pad 92. A watch 94 may be placed on this pad and is engaged by the cup 86 of the pick-up finger 32. The concave surface of the plastic cup is designed to allow the cup to be placed on the winding crown of a watch. It will be understood that very small watches have low intensity ticks and that the ticks of highly cushioned, shock-proof watches are not transmitted to the cases with very great intensity. The winding stem has a direct mechanical connection with the movement and we can pick up relatively high intensity ticks from the winding crown by use of the cup S6. It will be understood that a movement holder could be utilized instead of the foam rubber pad for supporting a watch movement to test the same in a variety of positions. The details of any specific movement holder do not form a part of this invention, and accordingly are not shown herein. Connection is made through a conventional shielded phonograph lead 96 to an amplifier shortly to be disclosed. it will be understood that each tick of the watch causes the crystal to generate a corresponding electrical po tential. The foam rubber pad 92, the rubber sleeve 72 and the various rubber grommets 4 3, 58, and 62 prevent the transmission of mechanical vibrations to the chassis. The frequency standard or timing unit 32 next will be discussed, and the details thereof may be seen in Figs. 5*8. This unit comprises a sheet metal base 98 having the floor .100 and an upstanding front wall 102 integral therewith. The floor and front wall are provided with right singularly disposed edge flanges 1M and res, and gusset plates ltlil are welded thereto at the confronting corners to rigidity the structure. A rear panel or wall 111 is spaced from and parallel to the front wall 102 and is secured in place by means of a right angle flange 112 along its bottom edge, this right angle flange being spot welded or otherwise suitably secured to the floor 190.

An elongated shaft 114 is rotatably mounted in the front wall 102 by means of a threaded bushing 116, a washer 118 and a flat nut 120 all as are well known in the radio art. The shaft 114 is provided at its rear end with a frusto-conical section 122 and an enlarged cylindrical section 124. A radially extending flange 126 is welded to or formed integral with the section 124. An enlarged cylindrical section 128 of Bakelite or other suitable insulating material is formed about the rear end of the shaft 114 next to the frusto-conical section 122 and carries a pair of commutator rings 130.

A pair of brushes 132 in the form of copper strips is mounted on an angle bracket 134 with the brushes in contact with the rings 130. The angle bracket 134 is welded or otherwise suitably secured to the front wall 162, and insulating strips 136 are provided on the rearwardly projecting arm thereof, the brushes being mounted between these insulating strips by means of suitable screws, washers, and nuts 138. It will be understood that the screws 138 are insulated from the brushes 132 by any suitable or convenient means. The wire ends 140 of a suitable two wire cord or line 142 are soldered or otherwise suitably connected to the lower ends of the brushes 132 in order to supply electrical potential to the commutator or slip rings 13b. The two Wire cord or line 142 is passed through a grommet 1454 in a suitable aperture in one of the gussets 108.

A circular sheet metal plate 146 is welded or otherwise suitably secured to the flange 126 to mount the plate 146 on the shaft 114. It will be understood that the frusto-conical section 122 and large cylindrical section 124 could be formed integral with the shaft 114 but more conveniently are in the form of a sleeve or collar which is welded, press-fitted, or otherwise suitably affixed to the shaft 114. A second circular sheet metal plate 148 is maintained in spaced parallelism with plate 146 by means of a plurality of spacers 150. The spacers conveniently are three in number and take the form of sheet metal strips having right angularly disposed feet 152 which are welded or otherwise suitably secured to the plates 146 and 148. A synchronous clock motor 154 is mounted on the second or rear plate 148 by means of screws 156 passed through the plate, through mounting lugs 158 on the clock motor, and having nuts 160 threaded on the ends thereof. The clock motor is of a conventional type having an eccentric output shaft (not shown) suitably geared to the clock rotor so as to rotate at 300'revolutions per minute. The motor is mounted eccentrically relative to the two plates 146 and 148 so that the output shaft is concentric with these plates. Suitable lead wires 162 extend from'the commutator or slip rings 130 through a rubber grommet 163 3 in the circular plate 146 to-the connecting wires 164 extending. from the clock motor.

The clock motor output shaft passes through the rear wall 110 by means of a conventional bushing and nut arrangement 166, and a washer 168 is interposed between this assembly and the circular plate 148 to prevent rearward movement of the plates 146 and 148, the motor 154, and the shaft 114. Forward movement is prevented by engagement of the insulating cylinder 128 with the bushing 116.

An insulating switch box 170 is mounted on the rear wall 110 and comprises a pair of end plates 172 which conveniently may be square in configuration, and a spacer 174 which likewise may be square in external configuration and which is provided with a cylindrical interior opening 175. The switch box may be made of any suitable material, and one that we have found to be particularly useful for this purpose is the plastic material commercially known as Lucite. The. end plates 172 and spacer 174 may be cemented'together by any known cement suitable for use with the particular material, and the parts are also held together by the bolts 176 which mount the switch box. The bolts 176 pass through the rear wall 110, through cylindrical sleeves 180 serving as spacers, and through the end walls 172 and spacer 174. Nuts 182 are threaded on the ends of the bolts 176 to hold the parts together. An extension shaft 185 slips over the clock output shaft and is secured thereto by a set screw 187 threaded radially through the shaft 185. The clock motor extension shaft 185 passes through suitable bushings 184r in aligned openings fitting in the end walls 172, and preferably cemented in place therein.

A post 186 is suitably mounted on the rear end Wall 172 and has an electrical contact 188 secured to it by any suitable means such as a screw 190 passing through it and threaded into the post. The electrical contact 188 may be made of copper or other suitable material such as bronze, and comprises a strip extending radially inwardly into alignment with the clock motor extension shaft 185, and offset almost into contact with the outwardly extending end 192 of this shaft. A contact piece 194 of tungsten or other suitable material is fastened on the electrical contact 188 and is in contacting engagement with the projecting end 192 of the clock motor extension shaft.

The clock motor extension shaft 185'is provided with a radial arm 196 which may be threaded thereinto and which extends substantially into contact with the interior wall of the spacer 174. A pool of mercury 198 is disposed in the bottom of the central opening 175 of the spacer and is in contact with a rod 200 extending through the spacer and downwardly therefrom. The contact arm 196 passes through the mercury with each revolution of the clock motor extension shaft 185 and thus completes an electrical circuit between the electrical connector 188 and the rod 288. A filler hoie 202 is provided in the upper part of the spacer 174 and is closed by a screw 204 threaded therethrough. A liquid oxidation inhibitor 206 also is introduced into the cylindrical interior 175 and overlies the mercury 198 to prevent corrosion of the surface thereof.

The shaft 114 extends forwardly through the front panel 30 and through the dial 34. A knob 208 and pointer 210 are mounted on the rod 114. The knob preferably is provided with a knurled or serrated periphery and is fixed to the rod or shaft 114 for rotatingthe shaft for rotating the clock motor 154. The pointer 2'10 frictionally fits on the shaft 114 for rotation therewith, but can be adjusted relative to the shaft. The panel section adjacent the dial .34 and knob 208 is shown as being perpendicular to the shaft 114 so that the pointer 210 may move in parallelism to the dial. This can be accomplished in any number of Ways such as by deforming that part of the panel into a vertical plane, or by 8 tippingthe; timing unit 32, or by -incorporating. a universaljoint in'the shaft 114, orby any other suitable means. Alternatively, the shaft 114 may pass through the. panel 30 at an angle, and the pointer may be of spring material or may be spring mounted so as to stay in contact with the face of the dial.

The dial 34 is shown .indetail in Fig; 8 andcomprises a circular section of sheet metal having a central opening. 212.for passing the shaft 114. The dial is provided at the top center. with a zero marking, and is provided with. suitable indicia indicating. the amount a watch is fast orslow in a twenty-four hour period. Thedial is shown as being calibrated toiridicate twenty-four hour errors up to two minutes fast or slow. The calibration could be extended, but it is not, as it is considered that a-watch that is off more than two minutes in twenty-four hours requires further repair or adjustment.

The electrical wiring for the watch timer including the amplifier therein may be seenin the schematic diagram ofFig. 9and attention now is directed. to that figure. The crystal pick-up is connected through the shielded lead 96 to the control grid 214 of an amplifying tube 216 which for illustrative purposes may be considered to be a type l2AT7. The crystal pick-up and the shield of the lead 96 are connected to a common ground'illustrated as a wire 218. A grid resistor 220 is connected from the control grid 214 to this common ground. The cathode 222 is connected through a resistor 224 to the ground 218, and also is connected through a coupling resistor 226 to the second control grid 228 of the tube 216. The first plate 230 is directly connected to the second cathode 232, andthe second plate 234 is connected through a load resistor 236 and a-dropping resistor 238 to a B-{- bus 240. The second control grid 228 further is connected through a resistor 242 to the junction between the resistors236'and 238. The connections to the heater or filament 244are conventionally indicated at x.r.

A by-passing capacitor 246 is connected across the tube 216 from the junction between the resistors 236 and 238- to the ground line 218 to eliminate unwanted frequencies. The plate234 is connected through a capacitor 248 to oneend of a potentiometer resistor 250, the other end of which'is connected to the ground wire 218. A slidable tap*252 on the potentiometer is connected to the control grid 254 of an amplifier tube 256 which conveniently can be a 6AU6 tube. The plate 258 of the tube 256 is connected through a load resistor 260 to the 13+ bus 240. The cathode 262isconnected through a cathode resistor 264 to the ground wire 218, while the suppressor grid 266 is directly connected to this ground wire. The connections to the filament 268 are indicated at x-x, and thescreen grid 270 is connected through a resistor. 272 to the 13-]- bus and through a capacitor 274 to the ground wire 218.

The plate 258 is connected through a. capacitor 276 to the grid 278 of a tube 288 which may be one half of a 12AT7. The grid-278 is further connected through a grid resistor 282 to the ground wire 218, and the cathode 28.4 is connected through a cathode resistor 286 to this same ground wire. The connections to the filament 288 again are indicated at x-x and the plate 290 is con nected through a load resistor 292 to the B+ bus 240.

The plate 290 is connected to a wire. 294, and a capacitor 296 couples this Wireto the ungrounded contact 298 of the jack 40. The grounded contact 300 of the jack is connected to the ground wire 218. This jack is adapted to receive a plug illustrated diagrammatically at 302 connected by a suitable wire or cable 304 to an ear phone 306. By plugging in the ear phone the jeweler or repair man can listen to the amplified ticking of the watch and in this manner can tell quite a bit about the operation and condition of the watch.

The wire 294 further is connected through a capacitor 308 to a wire 310, and this wire is connected in turn to the control grid 312 of a thyratron 314. The plate 316 of the thyratron, which may be a type 2D21, is connected through a load resistor 318 and a potentiometer resistor 320 to the B+ bus 240. The cathode 322 of the thyratron is connected through a charging capacitor 324 to the ground wire 218, and a resistor 326 is connected in parallel to the capacitor 324-. The thyratron suppressor grid 328 is directly connected to the cathode.

A voltage divider 328 is connected between the B+ bus 240 and the ground line 218. The voltage divider comprises series connected resistors 330, 332 and 334. The junction between the resistors 330 and 332 is directly connected to the plate 336 of a tube 338, and also is connected through a resistor 340 to the control grid 342 of this tube. This tube may consist of the second half of the l2AT7 tube comprising the tube 280. The cathode 344 is directly connected to the cathode 322 of the thyratron 314. A coupling resistor 346 is connected from the wire 310 to the junction between the resistors 332 and 334. It will be noted that the heater or filament 348 is connected at xx in the same manner as the previous tubes.

The B+ bus 249 is connected to one of the connectors 350 of a speaker socket 352. The corresponding pin 354 of the speaker plug 356 is connected to the primary 358 of an output or matching transformer 360. This primary is connected back to another pin 362 of the speaker plug. The corresponding connector 364 of the speaker socket is connected to a slidable tap 366 on the potentiometer resistor 320 for regulating the intensity of the impulses applied to the speaker.

The secondary 366 of the transformer 360 is connected to the voice coil 368 of the speaker 36, and also to one of the pins 376 of the speaker plug 356. The other end of the voice coil 368 is connected to the remaining contact 372 of the speaker plug.

The contacts 374 and 376 of the speaker socket corresponding to the last two mentioned pins of the speaker plug are connected to a shorting switch 378. The shorting switch is manually operable and may be controlled by one of the members 33 on the front panel. Connected in parallel. with the shorting switch 378 is a mercury switch 333 comprising the rotatable arm 196 and the mercury pool 198. The clock motor 154 is illustrated schematically at 158 in Fig. 9, and the extension shaft 135 is illustrated by a dashed line.

The Watch timer is provided with a conventional two wire flexible line or drop cord 384 which is connected to a double pole, single throw switch 336 operable by one of the control members 33. The switch is connected to a pair of wires 38% which are connected to the primary 393 of a power transformer 392, and in parallel to the wires 142 leading to the clock motor 158. The high voltage secondary 394 of the power transformer 392 is connected to the plates 3% of a full wave rectifier tube 398 such as 5Y3GT. The high voltage coil 394 is center tapped at 4th and this center tap is connected to a ground line 492 which is interconnected with the ground line 218 by a wire 494. The transformer 392. is provided with a five volt filament coil 406 which is connected to the filament 4-38 of the rectifier tube 398 as at 410 and 412. The connection point 412 is connected to a resistor 414 comprising part of a power supply filter 416. The remainder of this filter is a 11' section comprising a resistor 413 and a pair of capacitors 420. This 1r section is connected by wire 422 to the 13+ bus 240.

The power transformer 392 is provided with an additional filament winding 424 which is rated at 12.6 volts and which is center tapped to provide 6.3 volts, thereby to supply the remainder of the filaments as indicated at x--x. A pilot light 426 is connected across the filament winding 424 and is mounted in a readily visible position on the front panel 30 such as directly beneath the speaker 36 so that it is easy to tell at all times when the watch timer is turned on.

Operation A watch to be timed is placed on the foam rubber pad 94 and the'pick-up finger 32 is placed with the plastic cup 86 at the end thereof in contact with the watch. With the amplifier turned on and warmed up the ticking of the watch will be amplified and will cause the thyratron 314 to fire periodically. The ticking of the Watch triggers the thyratron. The jeweler or repair man may close the shorting switch 378 to complete the speaker circuit so that he may ascertain that the apparatus is working satisfactorily. The switch 378 then should be opened.

The mercury switch 383 will be closed to complete the speaker circuit each time the arm 196 moves through the mercury pool 198. if the watch is beating at substantially proper rate and if it is in phase with the movement of the arm we, the speaker circuit will be completed each time the watch ticks, and a click corresponding to the tick will be heard emanating from the loudspeaker 36. If the watch ticking and arm are not synchronized, then the knob 208 is turned to rotate the clock motor 154 to bring the arm into substantially zero degrees phase relationship with the watch ticking. The clicks from the loudspeaker then will be heard continuously if the watch is running at the proper rate.

If the watch is not running at the proper rate, it Will gradually advance or retard in phase relative to the closing of the mercury switch 380. When the phase shift has become great enough, the mercury switch will be open when the watch clicks, and nothing will be heard in the loudspeaker. The jeweler or repair man then turns the knob 2538 to pick up the clicks. Rotation of the knob will rotate the shaft 114, and thus rotate the clock motor 154, thereby bringing the closing of the mercury switch into synchronism with the ticking of the watch. The jeweler or repair man then again will hear the clicking in the loudspeaker, and the direction the pointer has moved with the knob 298 will indicate whether the watch is fast or slow.

With the clicks being heard inthe loudspeaker due to the proper zero degree phase relation between the closing of the mercury switch and the ticking of the watch, the jeweler or repair man must set the pointer 210 at the zero position, it being remembered that the pointer 210 is frictionally mounted on the shaft 114 so that it can be rotated relative to the shaft.

The jeweler or repair man then must wait one minute. Assuming, as we have been doing, that the watch is not running at exactly the proper rate, the watch ticking will pass out of synchronism with the closing of the mercury switch, and the clicks no longer will be heard in the loudspeaker. After the prescribed one-minute period has elapsed, the jeweler or repair man must turn the knob 208 again to rotate the shaft 11 for bringing the closing of the mercury switch into synchronism of the ticking of the Watch. The pointer 21% moves with. the shaft, and the number of minutes the watch is fast or slow in a twentyfour hour period can be read directly from the dial 34. The jeweler or repair man then can pass the watch as correctly timed, or can adjust the watch further, depending upon the type of watch and the desired accuracy.

It will be noted that the pick-up and speaker are mounted relatively close together. The sound of a small watch ticking is of very low intensity, and consequently the amplification must be quite high, and may be on the order of a thousand times. With the close proximity of the pick-up and speaker and this enormous amplification, feed-back and consequent unsatisfactory operation are to be expected. This is entirely avoided in our watch testing apparatus by the use of the thyratron tube. The recovery time of the thyratron is approximately twothirds between the time of watch ticks. That is to say, after it has fired with any given tick, the thyratron is not in condition to fire until two-thirds of the time to the next tick. Consequently, mechanical vibrations have 9." fed downbefore the thyratron is int condition. to zfire, and there. is no spurious output due to feed-back! ltwill be apparent that the watch timing apparatus herein disclosed meets the objects of theinvention. The apparatus is capable of accurately timing watches substantially instantaneously without the. wait of from one to several days necessary throughout the years of watch repair. The timer is substantially similar in construction and less expensive than prior electronic watch timers, and hence is available to any jeweler or watch repair man, whereas the prior electronic timers have been economically feasible only for very large scale operators. The readily available clock motor affords an accurate frequency standard, while the auditory and visible indications of the apparatus are readily comprehended and need no special interpretive skill. Furthermore, the apparatus is simple to use and needs no special operating skill nor training. The rotary or rockable mount of the clock motor affords a simple and inexpensive means for adjusting the phase between the ticks of the watch being tested and the frequency standard. The phonograph pick-up provides a simple, rugged, and readily available pick-up, while the incorporation of the thyratron positively prevent-s feed-back and consequent spurious operation.

It will be understood that the specific example of the invention herein shown and described is by way of illustration only. Various changes in structure are possible and form a part of the invention insofar as they fall within the spirit and scope of the claims.

We claim:

1. Apparatus for timing timepieces comprising means for detecting the ticks of a timepiece to be timed, said detecting means generating electrical signals in accordance with the ticks detected, means for amplifying the electrical signals, said amplifying means including a thyratron, means for translating the amplified electrical signals into audible sound, said means being impulsed by said thyratron, a frequency standard, means rendering said sound translating means operable when said frequency standard and said electrical signals are in phase, and rendering said sound translating means inoperative when said frequency standard and said electrical signals are out of phase, means for relatively adjusting the phase of the frequency standard and electrical signals, means for readjusting said phase after a predetermined time lapse and change in said phase due to inaccuracy of the timepiece being tested, and means interconnected with said readjusting means for indicating the accuracy of said timepiece upon operation of said readjusting means to readjust said phase.

2. Apparatus for timing timepieces as set forth in claim 1 wherein the sound translating means comprises a loudspeaker, the loudspeaker and the tick detecting means are mounted in close proximity to one another and the thyratron prevents feed-back.

3. Apparatus for timing timepieces comprising a crystal phonograph pick-up, a member extending from said crystal pick-up and adapted to engage a timepiece for transmitting the ticks thereof to said crystal pickup for generating electrical signals corresponding to said ticks, means for translating the electrical signals into perceivable indications corresponding to said ticks, a switch arranged in circuit with said last named means for rendering the same capable of indicating when said switch is closed and incapable of indicating when said switch is open, a synchronous motor having an output shaft, means for opening and closing said switch in accordance with the rotation of said motor output shaft, means for rotating all of said motor to bring the closing of said switch into phase with the electrical signals corresponding to the timepiece ticks, and means connected to said motor rotating means for indicating the degree of rotation of said motor when said motor is rotated after a predetermined time whereby to indicate the accuracy of said timepiece.

4. Apparatus for'timingiztimepieces as set fortliin claim 3 wherein the means for providingaauditory indication comprises a sound translating device providingan auditory indication.

5. Apparatus for timing timepieces as set' forth in claim 3 wherein the-meansproviding'a perceivable indication'comprises a loudspeaker, and'further including a thyratron for impulsing said loudspeaker, and means for amplifying the electrical signals corresponding to the detected ticks to trigger said thyratron.

6. A frequency standard unit comprising a synchronous motor having an output shaft, means rotatably mounting said motor for rotation of the entire motor about said output shaft, a switch including a liquid element and a rigid element, means interconnecting said output shaft and said switch for alternately closing and opening said switch in response to rotation of said shaft, and means for moving said motor and said switch as a unit for varying the phasing of said shaft and of the closing of said switch relative to one another.

7. A frequency standard unit as set forth in claim 6 wherein the switch comprises a rotary switch, and wherein one part of said rotary switch is mounted for rotation with said shaft, the switch being mounted for rotation as a unit with said motor.

8. A frequency standard unit comprising a synchronous motor having an output shaft, means mounting said motor for rotation of the entire motor about said shaft, a switch arm arranged for rotation by said shaft, means for making an electrical connection to said switch arm, means providing a pool of mercury positioned for momentary engagement by said switch arm as said switch arm rotates, means for making an electrical connection to said mercury pool, and means interconnecting said motor and the means providing said mercury pool for angular adjustment as a unit to vary the angular position of the mercury pool relative to said motor.

9. A frequency standard comprising a synchronous clock motor having an output shaft, means mounting said motor for rotation of the entire motor about said output shaft, said mounting means comprising a shaft fixed relative to said motor and concentric with said out put shaft, commutator rings insulatedly mounted on said second named shaft, electrical connections from said commutator rings to said motor, brushes engageable with said commutator rings for supplying electrical power to said motor, a switch arm connected for rotation by said output shaft, means providing an electrical connection to said switch arm, means providing a pool of mercury momentarily engageable by said switch arm upon rotation of said output shaft, means providing an electrical connection to said pool of mercury, and means interconnecting said motor and the means providing said mercury pool for angular adjustment as a unit to vary the angular position of the mercury pool relative to said motor.

10. Apparatus for timing timepieces comprising a pickup, a member extending from said pick-up and adapted to engage a timepiece for transmitting the ticks thereof to said pickup for generating electrical signals corresponding to said ticks, means for translating the electrical signals into perceivable indications corresponding to said ticks, a switch arranged in circuit with said last named means for rendering the same capable of indicating when said switch is closed and incapable of indicating when said switch is open, a synchronous motor having an output shaft, means for opening and closing said switch in accordance with the rotation of said mot-or output shaft, means for rotating all of said motor to bring the closing of said switch into phase with the electrical signals corresponding to the timepiece ticks, and means connected to said motor rotating means for indicating the degree of rotation of said motor when said motor is rotated after a predetermined time whereby to indicate the accuracy of said timepiece.

(References on following page) References Cited in the file Of this patent UNITED. STATES PATENTS Agnew June 7,1938 Wangeman Dec. 13, 1938 Journeaux et a1. Sept. 26, 1939 Gibbs Dec. 1, 1942 12 Dally Mar. 9, 1943 Auble Feb. 1, 1944 Corliss Mar. 22, 1949 John Feb. 20, 1951 Wickham e July 17, 1951 Bennett Apr. 22, 1952 Loria et a1. Nov. 22, 1955

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