US2889680A - Self-correcting clock - Google Patents

Description

June 9, 1959 Q KE 2,889,680

SELF-CORRECTING gLOCK F i1ed June 7, 1955 2 Sheets-Shem 1 IN VEN TOR.

OSCAR H. DICKE AGENT June 9, 1959 Filed June 7, 1955 2 Sheets-Sheet 2 HOURS1212 3 4 5 e 7 8 9101112 CAM 710 CAM 70C 1 r- CONTACTS l -I l -l -I -I -I I -I -I I SM IMPULSE INVENTOR.

. OSCAR H. DICKE flfM AGENT United States Patent SELF-CORRECTING CLOCK Oscar H. Dicke, New Bremen, Ohio Application June 7, 1955, Serial No. 513,662

4 Claims. (Cl. 58--34) This invention relates to clock mechanisms and more particularly to clock mechanisms including rate regulating means together With automatic means for setting the time manifesting means of such clock periodically in accordance with the time manifested by a synchronous motor operated from an alternating current source of regulated frequency and for simultaneously with such setting also adjusting the rate regulating means toward a better timekeeping adjustment and is an improvement over the invention disclosed in my pending application, Serial No. 447,271, filed August 2, 1954.

Mechanical clocks irrespective of their construction cannot keep perfect time, in that, even if the timekeeping error is very small, the error is cumulative and after a time builds up to a substantial error. Electric clocks although they keep average correct time so long as there is no failure of the regulated alternating current frequency power from which they are operated, do stop upon failure of the alternating current source and therefore are not reliable as time indicating devices.

In view of the foregoing and other important considerations, it is proposed, in accordance with the present invention, to provide setting means controlled periodically in accordance with a synchronous motor for setting a mechanical clock preferably at equally spaced time intervals and simultaneously with such setting also for adjusting the rate regulating means of such clock, the structure being such that if the time manifesting means is set forward the rate regulating means is adjusted in a direction to cause the clockto run faster, and if the time manifesting means is set backward, the rate regulating means is adjusted in a direction to cause the clock to run slower.

It is further proposed in accordance with the present invention to employ a synchronous electric motor which is incapable of restarting after the termination of a power failure either because the motor has a rotor of the toothed type and is inherently non-self-starting or because it is a self-starting motor, the operating circuit of which is taken through a holding contact, sometimes called a stick contact, and which holding contact is automatically opened upon each power failure, and must be manually restored to restart the motor. In one embodiment of the invention the clock may be mechanically set directly in a manner as disclosed in my prior Patent No. 2,185,334, and in another form of the invention the setting and rate regulation of the clock is performed electrically through an operating circuit including such holding contact and also a contact closed at specific time intervals. The holding contact in such operating circuit performs the function of preventing reclosure of such circuit, except manually, and then to hold it closed electro-magnetically only so long as such synchronous motor remains energized. An-

other purpose of the present invention, which is not necessarily incorporated in every application of the invention, resides in providing time manifesting means for the synchronous motor, which means preferably has its axis of rotation coaxial with the axis of rotation of the Patented June 9, 1959 time manifesting means of the mechanical clock, so that these two time manifesting means may readily be placed into juxtaposition over each other when the two time mechanisms are started into operation or are brought manually into synchronism after termination of a current cessation. During operation, if the mechanical clock does not keep correct time, its time manifesting means is periodically brought into synchronism with the synchronous motor operated time manifesting means, namely over each other, through the medium of said setting mechanism. Another feature of the invention resides in the provision of a disengageable clutch in the rate regulating gear train which when disengaged permits setting of the time manifesting means of the mechanical clock without imposing a change in the rate regulation of such mechanical clock. This clutch is necessary to afford setting alone as when the clock stopped because the mainspring was run down.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principle of the invention and the best mode, which has been contemplated, of applying that principle.

Fig. 1 shows. one embodiment of the invention;

Fig. 2 shows the synchronous motor, its holding energizing circuit and the setting cam contacts operated thereby and the setting circuit including the latter contacts;

Fig. 3 shows the relative timing of the control cams and the contacts operated thereby.

Fig. 1 structure: Referring now to Fig. 1 of the drawings, it will be seen that the clock gear train comprises gears 3, 5, 7 and 9 driving pinions 4, 6, 8 and 10, respectively. The gear 3 of the low-speed end of this clock gear train is driven by a mainspring contained within spring housing 12. This mainspring may either be key wound, as by key 13 illustrated, or may be electrically wound in any one of the various ways well known in the art and therefore requiring no specific illustration. The pinion 10 located at the high-speed end of the gear train, is directly connected to the escape wheel 11 which has its teeth engaged by a pallet 14 having a forked extension 14a engaging opposite sides of leaf spring 15 supporting the pendulum 16 containing a pendulum Weight or bob 16a. The pallet 14 is pivoted on a split pin 17 through which spring 15 passes and is operatively connected to the pendulum 16, although the pendulum 16 is actually supported by the leaf spring 15 supported by the round threaded plug 18 slideable in a round hole in bracket 19 but actually supported by threads in Worm-wheel 20, a key 21 sliding in a keyway in plug 18 preventing rotation of this plug. The net result is that the turning of this worm-wheel 20 will change the eifective length of the pendulum 16, and by changing the distance from pin 17, constituting the upper end of the pendulum, to the center of gravity of pendulum 16-16a, changing its period of swing or oscillation. Gear 5 and pinion 4 are connected to shaft 40 as by pin 4-1 and normally rotate at substantially one-fourth revolution per hour. This shaft 40 is in axial alignment with the axis of sleeve 69 and operatively connected thereto by the planetary gear train including gears 152 and 154 and pinions 153 and 155. Freely rotatable on the'one-fourth revolution per hour shaft 40 is a planet supporting gear 150, which supports a pin 151 projecting from the right side of this gear 150. On this pin 151 is rotatably secured an integral pinion and gear structure comprising a pinion 153 and gear 154 of twice the radius as that of pinion 153. The pinion 153 is nearer to the planet supporting gear but on the right side of this planet supporting gear 150 and is in mesh with the spur gear 152 permanently and firmlysecured to shaft 40 as by pin 156. The

gear 154 integral with pinion 153 on the other hand meshes with a pinion 155 rotatable on shaft 40 and having integral therewith a setting disk 30 similar to disk 30 shown in said pri'or ap'plication. Gears 152 and 154 are of the same diameter and pinions 153 and 155 are of the same diameter. The setting disk 30 is provided with a V-shaped notch 30a which will be engaged by the \l-shaped hammer 85 when the setting magnet SM is energized. This setting magnet SM will be momentarily energized by the setting circuit hereinafter de scribed. Since shaft 40 rotates clockwise as viewed facing the clock hands 70 and 71 at substantially one-fourth r.p.h. and since pinion 153 and 155 have radii half that of gears 152 and 154, the setting disk'30 and clock hand 70, or any other suitable time manifesting means, connected thereto by sleeve 69 will rotate at substantially o'ne r.p.h. in a clockwise dh'ection' as viewed from the right side of the clock asshown in Fig, 1. Since sleeve 69 is driven by shaft 40 through the medium of the planetary gear mechanism shown and described and since this sleeve 69 may also be driven by rotation of gear 150, as by turning setting knob 51, this planetary gear mechanism may be said to have two input members 40 and 150 and one output member 69. A small pinion 164 on shaft 123 and engaging pinion 124 containing a setting knob or key 51 is in meshed relation with the teeth of planet supporting gear 150. The shaft 123 is provided with a worm 165 in mesh with worm-wheel 166 contained on shaft 22 having keyed or otherwise secured thereto a clutch member of a clutch such as 77--78. This clutch 7778 has its clutch plates 77 and 73 pressed together by a spring 79 and may be held released by the clutch lever CL. The shaft 123 is also provided with a brake drum 116 which is frictionally held as by the brake 115. This brake 115 serves to prevent the rotary thrust of planet supporting gear 150 from operating the rate regulator during normal operation of the clock. It will be observed that the hour hand 71 secured to sleeve 169 is operated at one-twelfth the speed of the minute hand 70 through the medium of speed reducing pinions 170 and 172 and gears 171 and 173.

It will be remembered that shaft 40 rotates at substantially one-fourth r.p.h. and that sleeve 69 in which it is contained rotates at substantially one r.p.h. For

this reason the head at the right-hand end of shaft 40 must be round to allow such rotation. Around sleeve 69 is a second sleeve 169 integral with the gear 173 driven at one-twelfth the speed of sleeve 69 through the medium of pinions 170 and 172 and gears 171 and 173. This sleeve 169 supports and drives the hour hand 71.

On this second sleeve 169 is supported a third sleeve 69a driven at substantially one r.p.h. by the self-starting synchronous motor SSSM through the medium of pinions 180, 182 and 184 and gears 181, 183 and 185. Integral with the sleeve 69a is a pinion 186 which drives the third sleeve 169a at one-twelfth its speed through the medium of gears 187 and 189 and pinion 188. The sleeves 69a and 169a support clock hands 70a and 71a respectively. Integral with the sleeve 69a is a minute cam 70c and integral with the sleeve 169a is an hour cam 710. These cams rotate at substantially one r.p.h. and onetwelfth r.p.h., respectively, and. are of course driven by the synchronous motor SSSM. It will beseen that the gear 181 drives the pinion 182 through the medium of slip-clutch 190 to afford setting of the hands 70a and 71a through the medium of setting knob 191. The cam 70c closes contacts 303 and 304, whereas the cams 70c and 71c, in combination, close contacts 301 and 302 at the end of each twelve-hour period and which latter contacts again open just before contacts 303-304 reclose after this twelfth hour. There is however just sufficient overlap between these contact closings that the setting circuit is closed for one or two seconds at the end of each twelve hour period. As has been stated, the timing of the energiz'ati'on of the "setting magnet SM is a function of the overlapping relationship of contacts 301-302 and 303304. Inasmuch as contact closure as determined by the rise of a cam follower on a gentle slope of a cam is not conducive to accurate timing, the sharp dropotf of both cams 70c and 710 has been utilized to effect the necessary accurate timing. Cam 70c controls the critical opening time of contacts 303-304 as well as the closing time of contacts 301302, these latter contacts being restrained from closing at hourly intervals by cam 71c which permits that closure only at 12 oclock noon and midnight. v

The relative timing of the cams and their coaction with the contacts can be better understood by reference to Fig. 3. It will be seen that cam 71c, having a single depression and rotating at the rate of one revolution in twelve hours, is so disposed relative to cam 70c that its dropofi leads the corresponding dropoff on cam 70c. Consequently, the timing of the closure of contacts 301302 is determined by the latter cam. The closure 303304 and opening of contacts 301-302 is determined by the rise of cam 70c, and inasmuch as the camfollower portion 304 of contacts 303304 is longer than the corresponding portion 302 of contacts 301-302, contacts 301302 must perforce open before contacts 303304 close.

The net result of the relative speeds of cams 71c and 70c and of the relative disposition of the contacts 301302 and 303304 is shown in the lower portion of Fig. 3, where the closure of contacts 303304 at hourly intervals is shown. The twelve hourly closure of contacts 301 302, by virtue of their serial connection with contacts 303304 produces the SM impulse of the necessary duration at noon and midnight or at any other predetermined times.

By referring to Fig. 2 it will be seen that although cam 700 is ready to allow closure of contacts 301 and 302 that cam 710 does not allow such closure because the earn 710 assumes its six-hour position. It is also desired to point out that contact'fingers 302 and 304 are of slightly ditferent length such that contact 302 falls off the cam 700 about two seconds before cam 304 falls off this cam 700, so as to afford about a two-second closure of the setting circuit. T his setting circuit may now be traced in both of Figs. 1 and 2 as follows: starting at the alternating current source of current AC wire 296, stick contacts 297-298, wire 299 contacts 301302, contacts 303304, wire 305, setting magnet SM, wire 306, and back to the other terminal of said alternating current source A.C. If still closer timing of the closure of this setting circuit is desired a cam may, for instance, be employed which is operated by gear 183 and the contact operated thereby may be included in series in this setting circuit. The operating circuit for the synchronous motor SSSM may be traced as follows (see Figs. 1 and 2): starting at the alternating current source A.C. wire 296, stick contact 297, at times biased away from contact 298 by spring 250, wires 299 and 251, winding 253 of the synchronous motor SSSM, wires 254 and 306, and back to the other terminal of said alternating current source A.C.

Operation. The clock mechanism has been illustrated in its running condition as is manifested by closed condition of stick contacts 297-298, showing that the synchronous motor SSSM is energized, and as shown by thefact that minute hands 70 and 70a indicate substantially the end of the hour and that the hour hands '71 and 71a indicate substantially six oclock. The clock is brought into this condition by being wound at winding key 13, by starting the pendulum 16 swinging and by correctly setting the clock hands 70 and 71 to the correct time position during which setting the clutch lever CL is raised to release the clutch 7778 to prevent a change in the rate regulation during 'such setting operation. The synchronous 'motor' portion of the clock is then set by turning knob 191, as permitted by slip clutch 190, until hand 71a is hid behind hand 71 and until hand 70:: is hid behind hand 70 after which push button 310 is depressed to start the synchronous motor SSSM running. Release of the button 310 will not cause stopping of the synchronous motor because the stray magnetism from the field core will link the soft iron armature and contact 297.

When the synchronous motor SSSM has been operated long enough to cause the hands '70a71a to indicate twelve oclock, the cams 70c and 710 assume positions to cause contacts 301302 to close a few seconds before contacts 303304 open. This will cause momentary closure of the setting circuit heretofore traced. The closure of this setting circuit causes the V-shaped hammer 85 to enter the V-shapcd notch 30a of cam 30 to thereby bring the minute hand 70 directly over the minute hand 70a if it was not already there. Referring to Fig. 2 the contacts 303304 are opened by snap action a few seconds after the end of each hour and the contacts 301- 302 are closed by snap action exactly at the end of the twelfth hour, so that this energizing circuit is closed for a few seconds only at the end of each twelve-hour period. This is evidenced by the construction of cams 70c and 71c as shown in Fig. 2.

If the clock hand 70 was advanced during this setting operation, it caused the pinion 155 to turn clockwise as viewed from the front of the clock, thereby causing the pinion 153 to roll counterclockwise over gear 152 which is held relatively stationary by the escapement pallet 14, to thereby cause counterclockwise rotation of planet supporting gear 150. This causes a small amount of rotation to be transmitted to worm gear 20 in a direction to shorten pendulum 16 slightly through the chain of gearing including elements 164, 123, 165, 166, shaft 22, clutch 7778, gears 74, 75 and 76. Similarly, retrograde setting of the clock hand 70 will cause lengthening of the pendulum 16. The mechanical portion of the clock is thus repeatedly set at the end of successive twelve-hour periods and during each such setting the clock is rate regulated in proportion to the direction and magnitude of such setting, so that eventually the clock is perfectly rate regulated, after which the setting mech anism is periodically operated but effects no setting function. Should, due to wear, or the like, inaccuracy in the timekeeping quality of the clock develop effective setting and effective rate regulation will again take place.

Let us now assume that a current cessation occurs resulting in the de-energization of the synchronous motor SSSM. This will magnetically release the armature contact 297 and allow spring 250 to open the contacts 297--298 so that this motor SSSM cannot restart. The mechanical portion of the clock, however, keeps operating, and since it has been rate regulated to keep substantially correct time, reliable time will be indicated. When the nonoperating condition of the electrical portion of the clock is discovered, the clock hands 70a and 71a will be rotated by setting knob 191 until they will be hid by hands 70 and 71, respectively, after which push button 310 is depressed to restart synchronous motor SSSM. If desired, the electrical portion of the clock need not be restarted possibly for weeks since the clock should now be rate regulated to keep perfect time. If however desired, this setting and rate regulating feature of the invention may without delay be brought back into functioning.

In the event no automatic winding of the main spring, as by an electric motor, is provided for and hand winding by the key 13 has been neglected for a time to allow the mechanical portion of the clock to stop, then the clock is rewound and restarted and then clutch 77--78 is released and the mechanical portion of the clock is set by turning setting knob 51 until the clock hands 70 and 71 hide the hands 70a and 71a respectively. The clutch 77-78 is released during this setting to prevent false asaasao rate regulation. As already mentioned above, if desired, the hammer may be mechanically actuated by a nonself-starting synchronous motor of the toothed type in a manner as shown and described in my Patent No. 2,185,334. It should'be observed by looking at both Fig. l and Fig. 2 that the contact 302 is over both the onetwelfth r.p.h. cam 71c and the one r.p.h. cam 70c and that this contact drops down upon the contact 301 only at the end of the twelfth hour, namely at noon and midnight. The gear reduction in the rate regulating gear train extending from gear to worm gear 20 is such that the extent of rate regulation performed by any automatic setting produces a correction in the rate regulation which is less than a full correction, that is, produces an under correction. By such a structure successive settings at equal time intervals such as twelve-hour periods cause the rate regulation to gradually approach a rate regulation which causes perfect timekeeping. An over correction could not accomplish this result.

Having thus shown and described a single embodiment of the invention and having described a modified form of the invention, it is desired to be understood that the particular embodiment illustrated has been selected to facilitate disclosure of the nature of the invention and what form it may take rather than its scope and that various changes and modifications may be made within the scope of this invention so long as these changes do not depart [from the invention as defined by and come within the scope of the following claims.

What is claimed is:

l. An automatically rate regulated clock comprising: clock mechanism including a gear reduction train, a mainspring for driving the low-speed end of said gear reduction train, an escapement mechanism driven by the high-speed end of said gear reduction train; planetary gear mechanism including a planet-supporting member supporting a planet gear and having two input members and an output member and having one input member driven by said gear train; time manifesting means driven by the output member of said planetary gear mechanism; rate regulating means operatively connected to and for adjusting said escapement mechanism so as to operate at a predetermined speed and connected to the other input member of said planetary gear mechanism in a manner so that if said rate regulating means is correctly adjusted said time manifesting means will be driven by said gear reduction train through the medium of said planetary gear mechanism to correctly manifest the passing of time as determined by said escapement mechanism, if said time manifesting means has been operating too fast and said rate regulating means is operated in a direction and to an extent to cause said time manifesting means to be set through the medium of said planetary gear mechanism to correctly manifest time said rate regulating means is also operated and in a direction to cause said escapement mechanism to operate slower than it did before such operation of said rate regulating means, and if said time manifesting means has been operating too slow and said rate regulating means is operated in a direction and to an extent to cause said time manifesting means to be operated through the medium of said planetary gear mechanism to correctly manifest time said rate regulating means is also operated in a direction to cause said escapement mechanism to operate faster than it did before such operation of said rate regulating means; a source of alternating current of regulated frequency; a synchronous motor energized by alternating current from said source; a disk having a V-shaped notch and operatively connected to said time manifesting means; two cams, one driven by said synchronous motor at substantially one revolution per hour and the other driven at one revolution per a plurality of revolutions of said one cam; a contact closed when both cams are at the end of a revolution; a V-shaped setting hammer; a setting circuit which if energized causes said setting hammer to 7 enter the V-shaped notch of said disk provided said notch and said hammer are almost in registration and including said contacts; time manifesting means operated by said synchronous motor; said disk and its notch being so coordinated with the time manifesting means driven by said mainspring and said cams being so coordinated with the time manifesting means driven by said synchronous motor that the two time manifesting means indicate the same time after each operation of said setting hammer.

2. An automatically rate regulated clock comprising; a gear reduction train; a mainspring for driving the lowspeed end of said gear reduction train; an escapement mechanism driven by the high-speed end of said gear reduction train; rate regulating means operatively connected to said escapement mechanism for by its adjustment determining the rate of operation of said escape ment mechanism, time manifesting means; planetary gearing including a planet gear supported by a planet-sup porting member for interconnecting said gear reduction train, said time manifesting means and said rate regulating means in a manner so that if said rate regulating means is adjusted in a correcting direction said time manifesting means will be adjusted toward correctly manifesting time, also that if said time manifesting means is advanced by action other than that imposed by operation of said gear reduction train said rate regulating means is operated in a direction to cause the rate of operation of said escapement mechanism to be increased, and if said time manifesting means is moved in a retrograde direction said rate regulating means is operated in a direction to cause the rate of operation of said escapement mechanism to be reduced; a source of alternating current of regulated frequency, a synchronous motor energized by alternating current from said source; a disk having a V-shaped notch and operatively connected to said time manifesting means; two cams, one driven by said synchronous motor at substantially one revolution per hour and the other driven at one revolution per a plurality of revolutions of said one cam; contacts closed when both cams are at the end of a revolutioma V-shaped hammer; a setting circuit which if energized causes said hammer to enter the V-shaped notch of said disk provided said notch and said hammer are almost in registration and including said contacts; time manifesting means operated by said synchronous motor; said disk and its notch being so coordinated with the time manifesting means driven by said mainspring and said cams being so coordinated with the time manifesting means driven by said synchronous motor that the two time manifesting means indicate the same time after each energization of said setting circuit.

3. An automatically rate regulated clock comprising: clock mechanism consisting of a mainspring, a speedreducing gear train having its low-speed end driven'by said mainspring, an escapement mechanism driven by the highspeed end of said gear train, rate regulating means for by its adjusted position determining the rate at which said escapement mechanism shall be driven by said mainspring; time manifesting means; planetary gear mechanism including a rotatable planet supporting member, a planet gear pivotally supported non-coaxially on said planet-supporting member and two gears coaxial "with said planet-supporting member and meshing with said planet gear; one of said two gears being operatively connected to said gear train, the other of said two gears being operatively connected to said time manifesting means, and said palnet-supporting member being operatively connect ed to said rate regulating means, and these various operative connections and the gear ratios being such that said gear train drives said time manifesting means to correctly manifest the passing of time when said rate regulating means is properly adjusted and such that if said planetsupporting member is turned in a direction to set said time manifesting means forward said rate regulating means is moved to a higher rate position and if said assaeso planet-supporting member is rotated in a direction to set said time manifesting means backward said rate regulating means is operated to a lower rate position; a source of alternating current of regulating frequency; a synchronous motor operated by alternating current from said source; a disk having a V-shaped notch and operatively connected to said time manifesting means; two cams, one driven by said synchronous motor at substantially one revolution per hour and the other driven at one revolution per a plurality of revolutions of said one cam; contacts closed momentarily when both cams are at the end of a revolution; a V-shaped setting hammer; a circuit which if energized causes said setting hammer to enter the V-shaped notch of said disk provided said notch and said hammer are almost in registration and in eluding said contacts; time manifesting means operated by said synchronous motor; said disk and its notch being so coordinated with the time manifesting means driven by said mainspring and said cams being so coordinated with the time manifesting means driven by said synchronous motor that the two time manifesting means indicate the same time after each operation of said setting hammer.

4. An automatically rate regulated clock comprising: clock mechanism consisting of a mainspring, a speedreducing gear train having its low-speed end driven by said mainspring, an escapement mechanism driven by the high-speed end of said gear train, rate regulating means for by its adjusted position determining the rate at which said escapement mechanism shall be driven by said mainspring; time manifesting means; planetary gear mechanism including a rotatable planet supporting member, a planet gear pivotally supported non-coaxially on said planet-supporting member and two gears coaxial with said planet-supporting member and meshing with said planet gear; one of said two gears being operatively connected to said gear train, the other of said two gears being operatively connected to said time manifesting means, and said planet-supporting member being operatively connected to said rate regulating means, and these various operative connections and the gear ratios being such that said gear train drives said time manifesting means to correctly manifest the passing of time when said rate regulating means is properly adjusted and such that if said planet-supporting member is turned in a direction to set said time manifesting means forward said rate regulating means is moved to a higher rate position and if said planet-supporting member is rotated in a direction to set said time manifesting means backward said rate regulating means is operated to a lower rate position; a source of alternating current of regulated frequency; a synchronous motor operated by alternating current from said source; a disk having a V-shaped notch and operatively connected to said time manifesting means; two cams, one driven by said synchronous motor at substantialiy one revolution per hour and the other driven at one revolution per a plurality of revolutions of said one cam; a -!-shaped setting hammer; and means controlled by said cams for causing actuation of said setting hammer into the V-shaped notch in said disk provided said notch and said hammer are almost in registration each time said two cams are at the end of a revolution: time manifesting means driven by said synchronous motor; said disk and its notch being so coordinated with the time manifesting means driven by said mainspring and said cams being so coordinated with the time manifesting means driven by said synchronous motor that the two tir'ne manifesting means indicate the same time after each actuation of said setting hammer.

References Cited in the file of this patent UNITED STATES PATENTS

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