US3157984A - Timepiece movement for electric meters - Google Patents

Description

1964 JEAN-PAUL VUILLEUMIER ETAL 3,157,984

TIMEPIECE MOVEMENT FOR ELECTRIC METERS 5 Sheets-Sheet 1 Filed Aug. 13, 1962 mu lun'nn l Nov- 24, 1 JEAN-PAUL VUILLEUMIER ETAL 3,157,984

TIMEPIECE MOVEMENT FOR ELECTRIC METERS 5 Sheets-Sheet 2 Filed Aug. 15, 1.962

MN Nu 1964 JEAN-PAUL. VUILLEUMIER ETAL 3,

TIMEPIECE MOVEMENT FOR ELECTRIC METERS Filed Aug. 13, 1962 3 Sheets-Sheet I5 United States Patent This invention relates to timepiece movements for electric meters and in particular to timepiece movements with a synchronous motor and a reserve mechanism including a mechanical escapement.

Timepiece movements with a synchronous motor and a reserve mechanism including a mechanical escapement have already a long time ago been mounted at consumer stations of electrical current to control meter switches in systems having different tariffs. A timepiece movement with a synchronous motor in an electricity supply network, the frequency of which is exactly adjusted, dispenses the office supplying electricity to dispatch inspcctors to the different consumers to check and set their timepieces as this would be the case with timepieces regulated only by a balance-wheel or a pendulum.

In the electricity supply installations it is, on the other hand, quite impossible to use timepiece movements which would only be controlled by a synchronous motor, because a timepiece movement for such installations must keep running especially if a rather seldom but nevertheless unavoidable breakdown occurs in a local network or with a consumers.

The most simple way to keep the timepiece movement running during a breakdown therefore consists in providing the timepiece movement with a reserve mechanism including a mechanical escapement.

With most of the timepiece movements of this type which are known in the art, the reserve mechanism remains at rest during all the time the network is normally energized and means are provided for starting up the reserve mechanism when a breakdown occurs. If a starting up device for the reserve mechanism can be provided at relatively low cost, it will be observed that the reserve mechanism nevertheless remains at rest during very long time periods. it may thus occur that the re serve mechanism does not start under the impulse of the starting up device, because the lubricating oil of the balance-wheel pivots has either dried out or become hard in the meantime.

To remove this drawback, some manufacturers have provider their timepiece movements with means which cause tie reserve mechanism to run periodically during some minutes every couple of hours. The operation of these periodically operating starting up devices which are rather intricate, is however not absolutely safe.

'iimepiece movements provided only with a spring operated driving mechanism including a mechanical esescapcment to drive the indicating members and with a usual motor to wind the spring up periodically, have also been proposed. 'lhcse timepiece movements have however the drawback that they must include automatic regulating means to keep them in agreement with the astronomic time. In this respect, it has been proposed to set an electromagnet energized by the network current in the vicinity of the balance-wheel and to provide the same with magnetic poles, so as to obtain a balance-wheel oscillation having a frequency corresponding exactly to that of the network. These known devices do, however, not offer the safeguard required. It has, indeed, been observed that resonance phenomena can incidentally cause the balancewheel to oscillate with too large an amplitude.

3,157,984 Patented Nov. 24, 1964 The reasons therefore could, however, not be found as yet, so that this solution has been abandoned.

It is now an object of this invention to provide a timepiece movement comprising a synchronous motor and a reserve mechanism including a mechanical escapement in such a manner that the indicating member or members of this timepiece can be driven either by the synchronous motor or by the reserve mechanism and in which the reserve mechanism is permanently kept running.

For this purpose, use has been made, on the one hand, of the fact that the frequency of the electrical networks always varies, according to the load, about a nominal value comprised between a predetermined upper limit and a predetermined lower limit, and, on the other hand, of the fact that the network frequency is regulated in such a maner that the time periods during which the ellective frequency is higher than the nominal value thereof are exactly compensated by time periods during which the effective frequency is lower than said nominal value, so that the average frequency, measured during a relatively long time period and in the absence of general breakdowns, is exactly equal to the nominal frequency.

Further objects of the invention will become apparent in the course of the following description.

One embodiment of the timepiece movement according to the invention is represented diagrammatically and by way of example in the annexed drawings.

In the drawings:

FIG. 1 is a plan view of this embodiment, the baseplate of the movement being taken away and some parts being shown in section;

FIG. 2 is a part sectional view along line 11-11 of PEG. 1;

PEG. 3 is a part elevational view in the direction of arrow ill of FIG. 1;

PEG. 4 is a plan view on a larger scale of a particular device of the movement;

FIG. 5 is a diametrical section of the device of FIG. 4;

FIG. 6 is a plan view similar to that of FIG. 5, but showing the device in another working position;

PEG. 7 is a partial plan view on the same scale as FIG. 1, but showing the movement parts in different other working positions, and

PEG. 8 is a diagram illustrating the function of the movement.

The timepiece movement represented in the drawings is arranged for being associated with an electric control apparatus or a counting device such as a supply meter. it permanently drives an indicating member (not shown) which may consist for instance of a disc carrying a plurality of contact members arranged for opening and closing control circuits at predetermined moments. This timepiece movement therefore comprises a mechanism driven by a synchronous motor, a reserve mechanism including a power spring and a mechanical escapement, a winding mechanism for the power spring and a starting up mechanism for the reserve mechanism. All these mechanisms are located between a thin baseplate 1 and a bridge 2 (FIG. 2), which are connected to one another by pillars 3. A synchronous motor 4 comprising incorporated step down gear means is secured under bridge 2 so that these step down gears drive a shaft carrying a pinion 5. The latter meshes, on the one hand, with a winding wheel (5, and, on the other hand, with a driving pinion 7 freely mounted for rotary motion on a shaft 8 having both its ends fixed to bridge 2 and baseplate 1, respectively. Pinion 7 is secured to a disc 9 carrying a pawl til which is submitted to the action of a spring thread 11. A ratchet wheel 12 extends on the same level as pawl It), which thus cooperates with wheel 12 under the action of spring 11. Wheel 12 is driven by pinion '7 when the latter rotates clockwise from a viewpoint situall) ated at the top of FIG. 2 (arrow b in FIG. 1). Wheel 12 is set with force fit on a portion of a pinion 13 which is freely mounted for rotary motion on shaft 8 and which is spaced apart from disc 9 by a spacing washer 14%. A shaft 15 (FIG. 1), journalled in the baseplate l and in the bridge 2, carries a step down gear comprising a wheel 16 in meshing relation with pinion l3 and a pinion T7. The gear (16, 17 can freely rotate around shaft 15. Its pinion l7 drives a wheel 13 fixed to a pinion l9 and also journalled in bridge 2 and baseplate l. Pinion 19, which is located immediately below baseplate l, is in meshing relation with a wheel 29 coaxial to gear (16, and fixed for rotary motion to shaft 15. This gear 22h carries a tubular projection (not shown) which is coaxial to shaft 15 and extends above baseplate 1. The upper end of this tubular projection is provided with a screw-thread adapted for receiving the timepiece indicating member (not shown). Since pinion It? is driven by motor 4 in the direction of arrow b (FIG. 1) and since the wheel 2d, which is driven by gear (1%, 19'), rotates in the same direction as wheel 16, the wheels it: and 26 as well as shaft 15 rotate counterclockwise in FIG. 1. The step down ratios of the gears described as well as the rotating speed of pinion are chosen so that wheel Ztl makes a complete revolution in twenty-four hours.

The reserve mechanism of the timepiece described is arranged so as to drive pinion l3 and consequently the indicating member carried by shaft when the synchronous motor 4 has stopped, for instance because of a b eakdown in the network or because the motor 4 is voluntarily set out of operation for some hours.

The reserve mechanism comprises a barrel 21 mounted on an arbor Z2 and containing a power spring 2.3 which can drive the timepiece during about ten hours when it is completely wound up. The barrel 21 carries a wheel 24 extending between the upper surface of the barrel and the baseplate ll. Wheel 24 meshes with a wheel 25 which is pivotally mounted on an arbor 26 and which drives a gear 2'7 pivotally mounted on a stud 28 fixed to basepiate 1. Wheel 25 and arbor 26 have still further functions which will be described hereinafter. Gear 2'7 drives a pinion 29 similar to pinion '7 and which is also freely mounted for rotary motion on shaft 8 opposite pinion '7. Pinion 2d carries a disc 3% provided with a spring-pressed pawl 31. Barrel 21 rotates counterclockwise in PEG. 1 (arrow c). This FIG. 1 shows that pinion 253 and disc 3d rotate clockwise, like pinions 7 and 13. A wheel 32, similar to wheel 12, is also set with force fit on a portion of pinion 12 so as to extend at the upper end of this pinion on the same level as pawl 31 which cooperates therewith. Pinion 29, which is driven by the power spring 23, can thus also drive pinion l3 and consequently the indicating member mounted on shaft 15, if motor 4- has stopped. The running speed of the reserve mechanism described is regulated by a mechanical escapement. A toothing is therefore provided at the periphery of disc 13 and this toothing is set in meshing relation with the pinion of a step down gear 33, the wheel of which is in meshing relation with a pinion 34 mounted on the shaft of an escapement wheel 35. The latter actuates a pin lever 36 mounted on a shaft 37. A balance-Wheel 38 without screws is journalled in two bearings 39 carried by the baseplate ii and the bridge 2, respectively. This balance-wheel oscillates under the action of the impulses transmitted thereto by lever 36, while a hair-spring 4i? ensures the isochronism of the balance-wheel oscillations. The reserve mechanism described still comprises a regulator 41 to adjust the frequency of the balance-wheel oscillations.

As with the usual movements, the barrel arbor 22 comprises a relatively thick middle portion 42 to which the inner end of spring 23 is anchored and it carries a wheel 4-3 enabling spring 23 to be wound up. Wheel 43 is prevented from rotating in one direction by a retaining idevice which comprises a wheel 44, which is in meshing relation with wheel 43 and is mounted for rotary motion on a stud 45. A coil spring 36 surrounding stud 45 permits to rotate wheel 43 in the direction of the arrow c (FIG. 1) to wind up spring 23, but it prevents this wheel from rotadng in the other direction under the action of spring 23 by firmly encompassing stud Spring 23 can thus not run down incidentally once it has been wound up.

As shown in FIG. 2, the shaft 25 on which wheel 25 is mounted furthermore carries wheel 6 and a wheel 47 located above wheel 6 and meshing with the winding wheel 43.

The three wheels 25, 4'7 and 6 are idly mounted on shaft 25. A clutching device described hereinafter and located between wheels 27 and 6 permits to clutch these two wheels to one another. When these two wheels are clutched to one another and when the motor runs, the winding wheel 4-3 is driven in rotation in the direction of arrow c and the spring 23 is wound up.

The movement described still comprises a limitation device which automatically unclutches wheel 47 from wheel 6, when the spring has been wound up completely, wheel 47 then remaining at rest while wheel 6 is still driven in rotation by pinion 5, however, without any further action. This lhnitation device is mounted on shaft 26 between wheels 25 and 47 (FIGS. 2 and 3). it comprises a plurality of independent co-axial discs 43, each of which is mounted for free rotation around shaft Each disc 48 carries a downwardly extending nose at its periphery, said nose extending opposite the periphery of the adjacent disc 48. The limitation device furthermore comprises a stop Stl secured to wheel 25. This stop extends opposite the periphery of the upper disc as, so that the nose of the upmost disc may come into abutting engagement with this stop. Finally, the nose 49 of the lowest disc 43 en ers the clutching device located between wheels 47 and 6. The position of discs 4% represented at PEG. 2 corresponds to the moment at which the spring 23 has been completely wound up. The Wheels 47 and 6 are accordingly disconnected from one another. The wheel 4'7 remains at rest and the wheel 25, driven by wheel 24, rotates in the direction of arrow d (FIG. 2) at a speed regulated by the balance-wheel Eli. The stop so accordingly moves from the nose of the upmost disc 48 away. When wheel has made almost a complete revolution, the stop 5t) comes in abutting engagement with the opposed edge of the nose d9 of the upmost disc 4-3 and it drives the latter in rotation. When this first disc 58 has made approximately one complete revolution, its nose 49 comes in turn in abutting engagement with the nose 49 of the second disc which will then also be driven in rotation together with stop This stop 549 thus successively drives each disc 48 as long as wheels 47 and d are disconnected from one another. At the moment at which the clutching device arranged between wheels 47 and 6 becomes operative, the wheel 47 however starts rotating in the direction of arrow (1, but at a higher speed than wheel 25. It drives thus the lowest disc 48 and each disc 48, the nose d9 of which re mained in the position of FIG. 2. it soon catches the last disc which had been driven by wheel 25 and it drives the same in the direction of arrow d at a higher speed than wheel 25. When this disc has made a complete revolution with respect to the adjacent disc located immediately thereabove, its nose 4% comes in abutting engagement with that of the upper disc and drives the same in rotation. Each disc 48 is thus driven in succession until the upmost disc 48 comes in abutting engagement with stop Ed by moving from the right to the left in FIG. 2. Since the speed of wheel 25 is reguiated by the balance-wheel 38 and remains constant, the whole row of discs 152 is locked by stop Stl and the nose 49 of the lowest disc -38 gives a locking impulse to the clutching device of wheels 4-7 and 6, thus disconnecting wheel 4-7 from the latter and causing this wheel 47 to stop. All the discs d 4-8 thus come to stand at rest and the above described process can start again.

The clutching device mentioned above is represented in FIGS. 4, 5 and 6, in which it can be observed that wheel 6 carries, on the one hand, a cross-shaped cam 51 formed with a central tubular projection riveted in a central opening of wheel 6 and, on the other hand, a pipe 52 set with force fit into the tubular projection of cam 51. A disc 53, provided with a finger 53a, is set at the upper end of pipe 52. The wheel 4-7 is idly mounted for rotary motion on pipe 52 and extends between disc 53 and cam 51. This wheel 47 carries in turn an upper pawl 5d pivotally mounted on a stud 55 and a lower pawl 56 pivotally mounted on the same stud 55. Pawls 54- and 5a? are connected together by a pin 57 extending through an opening 5d of wheel 4-7, so that these pawls rock together. Wheel 47' moreover carries, on its upper surface, a latch mounted on a stud til and, on its lower surface, a lever 61 pivoted at 62. Finally, the pawl $4 and the latch 5% are submitted both to the action of a spring 63: anchored to a stud 64. The different pieces mounted on wheels 4'7 and 6 constitute the clutching device mentioned above.

When these pieces are in the position represented in FIG. 4, the clutching device is operative, i.e. the wheels 47 and 6 are clutched to one another. As shown in that figure, the lower pawl 5'6 is provided with a nose as which locks one end of lever 61. Moreover, the upper pawl ti t is provided with a nose as which bears against a camming surface 67 of latch $9. Pawls 54 and 56, which are connected to one another, and latch 59 are all together held in the position of FIG. 4 by spring 63. The lever 61 comprises a projection 68 against which one branch of the cross-shaped cam 5i strongly butts, when the lever tilt is firmly held in the position of FIG. The clutching device described is thus in clutched position in PEG. 4 and wheel 5 drives wheel 47 in the direction of arrow e by means of the cam 51 and the lever 61 which is held in the position of FIG. 4 by nose d5 of pawl Moreover, pawl 54 comprises a nose 69 which drives nose d9 of the lowest disc in rotation as long as the resistance opposed by this disc is smaller than the strength of spring When all the discs 48 have reached the position represented in FIG. 2, i.e. when wheel 4-7 has made a number of revolutions which is equal to the number of discs which have been driven by wheel 25, less the sum of the widths of the corresponding noses 49 and when nose 4? of the upmost disc comes in abutting engagement with stop it thus locking all the discs 43, a force is then exerted on pawl which causes the same to rock around its stud 55. The nose or of this pawl then enters a notch 7d of latch 59 while the lower pawl 56 releases lever til (FIG. 6). The branch of cross 551i, which bears on projection 63, now pushes lever outwards, so that cross 51 may rotate alone without driving wheel 47. The wheel 6 is thus disconnected from wheel 47. The other end of lever er, constituted by a nose 71, however enters then the path of the branches of cross 51. Each cross branch thus successively urges lever er into the position of PEG. 4. This lever 61 is however not caught in the position of MG. 4 because the pawls 5d and 5d are held by latch 59 in the position of FIG. 6. After less than one revolution of wheel 6, the finger $311 however comes in abutting engagement with the nose 85 of latch 59 and pushes this latch outwards thus releasing the pawls 5d and as which come then back to their original positions shown in FIG. 4. The wheels l"? and ti are thus clutched together again and they re main in this clutched position until the discs dd come in the position of EEG. 2 again, i.e. until spring 23 has been completely wound up. The winding mechanism disclosed is thus periodically set in winding position by clutching wheels at? and 6 together and it remains in this position every time until spring 23 is completely wound If a breakdown of the current supply occurs between two actuations of the clutching device described and if the reserve mechanism has run during that breakdown thus unwinding spring 23, the number of winding revolutions made by wheel 47, before the clutching device is set out of action, will of course be greater than if no breakdown had occurred. Since wheel 25, driven by barrel El, rotates at a speed of substantially one revolutron per hour, while wheel 6 substantially makes two revolutions per hour, half an hour at most will elapse from the moment at which the wheels 47 and d are disconnected from one another until finger 53a clutches them together again, if the synchronous motor 4 is nor mally running. During that time the spring 23 has been wound down through half a revolution of wheel 25 and the time required for winding spring 23 up again is half an hour.

To start up the timepiece movement described, the motor 4 needs only to be connected to a proper power source of alternating current. This motor drives then the indicating member of the timepiece by means of the pinions 7 and 13 and the gears (l6, l7) and (l8, 19) as described above. At the same time it winds up spring 23. When this spring has been wound up by two revolutions of its winding wheel, the balance-wheel 3% should start oscillating by itself. It could however remain at rest, if the lubricating oil had for instance become pasty during either a long stockage before the first use of the timepiece movement or a long period of rest of the same.

To remove this drawback, the movement described still comprises a starting up mechanism for the balance-wheel 38. This mechanism, represented in F168. 1 and '7, is actuated by a pin 72 carried by wheel 6. It comprises an arm 73 extending above wheel 47 (FIG. 3) and having one end extending on the same level as balancewheel and provided with a resilient tongue "7d adapted for giving an impulse to the balance-wheel Ed by con ing in contact with its outer heavy ring. The arm 73 is riveted onto a substantially triangular plate 7S comprising three straight edges 76, '77 and 78 arranged for cooperation with pin '72, an edge 79 arranged for cooperation with a fixed stop and a slot 81 cooperating with a guiding stud $52. A spring 553 has one end anchored to one of the pillars 3 and the other end anchored to one corner of the triangular plate 75.

The plate '75 and the arm 73 are normally in the resting position shown in FIG. 1, in which the edge 79 bears against the stop lid, the stud S2 is at the titer end of slot all and the spring is almost unbent. When the pin 72 engages edge re, the triangular plate guided, on the one hand, by the stud S2, and, on the'other hand, by the stop hit is shifted away from its resting position substantially without accomplishing any rotary motion and it comes thus in different intermediate positions such as that represented in full lines in PEG. 7. This translatory motion of plate 75 continues until pin 72 reaches the corner formed by edges '76 and 7?, where a small notch 84 has been provided. Pin then causes plate 7'5 to rock about stud 82 against the action of spring 83, while arm 73 moves toward the outside of the movement as shown by thin lines in Fit 7. This rocking motion of plate 75 continues until l2 reaches the end of edge '77. At that moment, the plate '75 is released and the spring 33 can bring it back to the position of PEG. 1 by a very quick motion. During this last motion, the plate 75 first slides with its slot 81 along stud 32 under the action of spring 83, so that the resilient tongue 7 approaches the balance-wheel The edge 7% of plate 'FS simultaneously follows pin '72. thus causing plate '75 to rock around stud 82. When pin 72 releases plate 75, the latter consequently moves tongue 74 along such a path that that tongue slightly engages the outer edge of balance-wheel 38 and gives the same a starting impulse. As long as the motor 4 is kept running, every revolution of wheel 6 imparts the balancewheel a starting up impulse.

To understand the function of the timepiece movement, the different parts of which have been described above, it should be noted that the reserve mechanism is adjusted by means of regulator 41 in such a manner that this reserve mechanism drives wheel Ztl carrying the timepiece indicating member slow three to five minutes a day. Normally the pinion '7, driven by motor 4, rotates faster than pinion 29, which is driven by barrel 21, since pinion 7 rotates at a speed which corresponds to the exact time. it is therefore pawl 10 cooperating with wheel 12, which drives pinion 13, whereas wheel 32 slides under pawl 3?. because it rotates faster than disc 3d. The reserve mechanism thus runs without any influence on the indicating member of the timepiece described. if the motor now stops for any reason, the pinion 13 also stops, but only during the very short time which is necessary for pawl 31 to engage a tooth of wheel 32. Pinion 13 is then driven in rotation by pawl 31 and pinion 29 at a speed controlled by the balancewheel 38.

The timepiece movement described is of a most simple design. Moreover, it operates automatically in an absolute safe manner. Since the reserve mechanism permanently remains in running condition, the lubricating oil of its movable parts can neither dry out nor become pasty, so that driving the indicating member of the timepiece will always be ensured, even if the motor stops, provided that the time during which that motor remains at rest do not exceed about ten hours. Moreover, winding up the power spring of the reserve mechanism is automatically ensured by the motor 4. Finally, the starting up mechanism actually ensures the reserve mechanism to start up, for instance when the timepiece movement is used for the first time or after it has been a long time at rest.

Although the reserve mechanism is regulated so as to run a little slower than the astronomic time, it can be observed in practice that the indicating member carried by the timepiece movement described always remains substantially in concordance with the astronomic time, even after very long running periods. Tests made with the movement described have indeed shown that the indicating member carried thereby, did not only not run slow, but had, on the contrary, rather the tendency to be a little fast. This appears to be due to the fact that the number and the duration of the breakdowns in the electricity supply network, causing the motor 4 to stop, are not numerous during a year and are in general short. An interruption of the electricity supply is usually due either to a breakdown or to a voluntary interruption undertaken for instance to carry out a repair or to mount a new installation.

Statistics show that the sum of the interruptions of the electricity supply during a year is comprised between three and five hours. This time is at first glance that during which the indicating member of the timepiece is driven by the reserve mechanism. If the latter has been adjusted so as to run four minutes slow during twentyfour hours, the indicating member of the timepiece should be, after a year, thirty to fifty seconds slow, because of the usual interruption in the electricity supply during that time.

This theoretical value does, however, not correspond to the value observed in practice. This is due to the fact, that the synchronous motor 4 does not always run at exactly the same speed. This motor runs indeed in synchronism with the network frequency and the latter always varies about its nominal value between predetermined limits. These limits are usually .5 of the nominal frequency lower and higher, respectively, than the same. The diagram of FIG. 8 shows the upper limit A of the frequency, which is of 50.25 cycles, and the lower limit B, which is of 49.75 cycles. With all electrical networks, the frequency variations are thoroughly checked and carefully adjusted in such a manner, that the average frequency, calculated during a long time period, is exactly equal to the nominal frequency. With a network of 50 cycles (FIG. 8), when the frequency happens to remain above the nominal value during a time period C or G and then drops below 50 cycles during a period D or I, the frequency is regulated in such a mannor, that the average frequency during time periods such as 0-D or G-I is exactly equal to 50 cycles. By adjusting the frequency in that manner, time periods such as E, during which the frequency is 0, because of a breakdown, are obviously not taken into account.

Now, with a reserve mechanism adjusted with regard to the astronomic time so as to be less slow than the synchronous motor during the time periods, in which the network frequency has dropped to its minimum value, the movement described will run faster and faster as long as there is no breakdown or an interruption of the operation of motor 4 due to another reason. In the diagram of FIG. 8 the line F shows the running speed of the reserve mechanism, which has been adjusted so as to run slow four minutes a day. Thus the relative value of this slow adjustment, which is .3% of the nominal value, is less important than that which is indicated by the line B which is of 5%. When during a period such as H the network frequency drops more than 3% below the nominal frequency, it is thus the reserve mechanism and not the synchronous motor which drives the indicating member of the timepiece movement, because pinion 2a rotates then faster than pinion 7. Now, the time period :1 is comprised within a longer period I, during which the network frequency is lower than the nominal value, this period I being adjusted so as to compensate period G and to obtain an average frequency during the period (3-1 which will exactly be of 50 cycles. Since the efiective running speed of the timepiece indicating member is however not that at which it would normally have been driven by the motor 4 during the period H, but is higher, the compensation for the fast running accumulated during period G will not be ensured exactly during period I, and, at the end of period I, the indicating member will accordingly be a little fast.

Thus, with a reserve mechanism adjusted for instance so as to be slow five minutes a day, i.e. 35% below the nominal value, and with a network frequency of 49.75 cycles, i.e. .5% below the nominal value, during half an hour, the indicating member, instead of showing the exact time after the period I, as it would be the case if it had always been driven only by the synchronous motor, will be .15% fast during half an hour, i.e. 2.7 seconds. Since periods such as H, during which the network frequency drops in the vicinity of its lower limit, are rather numerous, the fast runnings or" the indicating member accumulated during those periods can wholly compensate for the slow runnings accumulated during the current breakdowns, during which the indicating member is driven too slow by the reserve mechanism.

Tests have shown that the fast runnings mentioned above and which are accumulated during a long period also compensate for the short periods during which pinion 13 is at rest and which can occur between the moment at which the motor 4 stops and the moment at which pawl 31 starts driving wheel 32, every time pawl 31 is not fully engaged in a tooth gap of wheel 32 when motor 4 stops.

Since the regulator 41 of the reserve mechanism permits to adjust the balance-wheel frequency at will within very large limits from 0 to 10 minutes slow during twenty-four hours, the movement described can easily be adjusted in accordance with the actual operating conditions of any electrical network, while considering the adjusting features of this network and the frequency of its breakdowns.

The movement described has finally the advantage to constitute a unit carried by a strong framework of small sizes enclosing all the necessary elements for ensuring a wholly automatic run of the movement. To set this movement into operation, its synchronous motor needs only to be connected to the network and its indicating member to be set. As soon as the motor has been connected to the network, the power spring 23 is wound up. When this spring has been wound up through almost two revolutions of the barrel arbor, the balance-wheel 38 starts running. From that moment, the reserve mechanisms will operate without interruption. Moreover, it the balance-wheel does not start running from itself the first time the movement is set into operation or when it is set into operation after a long interruption, the arm 73 will automatically start it up. it is therefore not necessary to check whether the reserve mechanism etTectively starts.

The movements of arm 73, which are periodically repeated, cannot disturb the isochronism of balance-wheel 38 very much. Moreover, since these movements only occur when the synchronous motor is running, because of pin 72 which is mounted on wheel 6, the arm '73 will generally give an impulse to the balance-wheel only when the reserve mechanism runs without any driving action on the indicating member of the timepiece movement, so that the small perturbations of the running speed. of the reserve mechanism caused by the starting up arm '73 will not have any influence on the running speed of the timepiece indicating member.

Although one embodiment of the timepiece movement according to the invention has been described in detail with reference to the accompanying drawings, it should be understood that various changes in the shape, sizes and arrangement of parts can be resorted to without departing from the spirit of the invention or sacrificing the advantages thereof.

We claim:

1. In a timepiece movement, in combination, a motion work, a synchronous motor adapted for running at speeds ranging between a minimum and a maximum value, but having a predetermined average value, first motion transmitting means including a first free-wheel mechanism and connecting said synchronous motor to said motion work for driving the same, a reserve mechanism adapted for running uninterruptedly, and second motion transmitting means including a second free-wheel mechanism and connecting said reserve mechanism to said motion work for driving the same, said reserve mechanism being adjusted so as to be able to drive said motion work at a predetermined speed lower than that at which said motion work is driven by said synchronous motor, when the same is running at a speed equal to said predetermined average value, but higher than that at which said motion work would be driven by said synchronous motor, when the same is running at a speed equal to said minimum value.

2. In a timepiece movement, in combination, a motion work, a synchronous motor adapted for running at speeds ranging between a minimum and a maximum value, but having a predetermined average value, first motion transmitting means including a first free-wheel mechanism and connecting said synchronous motor to said motion work for driving the same, a reverse mechanism adapted for running uninterruptedly and including a mechanical escapement, and second motion transmitting means including a second freewheel mechanism and connecting said eserve mechanism to said motion work for driving the same, said reserve mechanism being adapted for driving said motion work under the control of said escapement at a predetermined speed lower than that at which said motion work is driven by said synchronous motor, when the same is running at a speed equal to said predetermined average value, but higher than that at which said motion work would be driven by said synchronous motor, when the same is running at a speed equal to said minimum value.

3. In a timepiece movement, in combination, a motion work, a synchronous motor adapted for running at speeds ranging between a minimum and a maximum value but having a predetermined average value, first motion transmitting means including a first free-wheel mechanism and connecting said synchronous motor to said motion work for driving the same, said motion work running at a nominal speed when said synchronous motor runs at a speed equal to said predetermined average value, a reserve mechanism adapted for running uninterruptedly, and second motion transmitting means including a second free-wheel mechanism and connecting said reserve mechanism to said motion work for driving the same, said reserve mechanism being adjusted so as to be able to drive said motion work at a speed being an amount lower than said nominal speed, which is about 60% to 70% of the difference between said predetermined average value and said minimum value.

4. in a timepiece movement, in combination, a mo tion work, a synchronous motor adapted for running at speeds ranging between a minimum and a maximum value but having a predetermined average value, first motion transmitting means including a first free-wheel mechanism and connecting said synchronous motor to said motion work for driving the same, said motion work rur ring at a nominal speed when said synchronous motor runs at a speed equal to said predetermined average value, a reserve mechanism adapted for running uninterruptedly and including a mechanical escapernent, and second motion transmitting means including a second free-wheel mechanism and connectin said reserve mechanism to said motion work for driving the same, said reserve mechanism being adapted for driving said motion work under the control of said escapement at a speed being an amount lower than said nominal speed, which is about 60% to 76% of the dilierence between said predetermined average value and said minimum value.

5. in a timepiece movement, in combination: a motion work; a synchronous motor adapted for running at speeds ranging between a minimum and a maximum value, but having a predetermined average value; first motion transmitting means including a first free-wheel mechanism and connecting said synchronous motor to said motion work for driving the same; a reserve mechanism adapted for running uninterruptedly and comprising a mechanical escapement, a power spring controlled by said escapement, a barrel carrying a toothing and having one end of the power spring anchored thereto, a barrel arbor having the other end of said power spring anchored thereto, and a winding wheel on said barrel arbor; second motion transmitting means including a second free-wheel mechanism and connecting the toothing carried by said barrel to said motion work for driving the same under the control of said escapement at a predetermined speed lower than that at which said motion work is driven by said synchronous motor, when the same is running at a speed equal to said predetermined average value, but higher than that at which said motion work would be driven by said synchronous motor, when the same is running at a speed equal to said minimum value; and a winding mechanism comprising a first wheel in meshing relation with said winding wheel, a second wheel driven by said synchronous motor, a clutching device inserted between said first and said second wheel and being adapted for remaining at rest either in a clutched or in an unclutched position, and a control mechanism having a first group of means carried by said second wheel and causing said clutching device to pass from its unclutched position into its clutched position when said wheel makes at most one revolution with respect to said first wheel, and a second group of means causing said clutching device to pass from its clutched. position into its unclutched position when said power spring has been wound up completely.

6. A timepiece movement according to claim 5, said first and said second wheel of the winding mechanism being coaxial, said winding mechanism further comprising a third wheel coaxial to said first and said second wheel, said third wheel being in meshing relation with the toothing carried by said barrel and rotating in the same direction but slower than said first and said second wheel, and said second group of means comprising a stop on said third wheel causing said clutching device to pass from its clutched position into its unclutched position when said first wheel has reached a predetermined position with respect to said third wheel under the driving action of said second wheel.

7. A timepiece movement according to claim 6, said control mechanism comprising a pile of discs coaxial to said three wheels, each disc being rotatable with respect to the other discs and carrying a projection adapted for driving in rotation one of the adjacent discs.

8. A timepiece movement according to ciaim 7, the projection of one of the outmost discs of said pile extending on the same level as said stop and being arranged for cooperation therewith, the projection of the other outmost disc extending within said clutching device and causing the same to pass from its clutched position into its unclutched position when the projections of all discs of said pile are in abutting engagement with one another and when the first outmost disc of said pile is locked by said stop.

9. In a timepiece movement, in combination, a motion work, a synchronous motor adapted for running at speeds ranging between a minimum and a maximum value, but having a predetermined average value, first motion transmitting means including a second free-wheel mechanism and connecting said synchronous motor to said motion work for driving the same, a reserve mechanism adapted for running uninterruptedly and comprising a mechanical escapement having a balance-wheel, second motion transmitting means including a second free-wheel mechanism and connecting said reserve mechanism to said motion work for driving the same, said reserve mechanism being adapted for driving said motion work under the control of said escapement at a predetermined speed lower than that at which said motion work is driven by said synchroi2 nous motor, when the same is running at a speed equal to said predetermined average value, but higher than that at which said motion work would be driven by said synchronous motor, when the same is running at a speed equal to said minimum value, and a mechanism periodically giving impulses to said balance-wheel under the control of said synchronous motor.

10. A timepiece movement according to claim 9, said mechanism periodically giving impulses to the balancewheel comprising a yieldable member mounted both for translatory and rotary motion and capable of moving from a position of rest to a position of bending along a first predetermined path and from said position of bending to said position of rest along a second predetermined path different from said first predetermined path, said yieldable member having a portion engaging the balancewheeel or" said reserve mechanism when said yieldable member moves along said second predetermined path, spring means urging said yieldable member toward its position of rest and normally maintaining the same in said position, a wheel driven by the synchronous motor, and a driving member on said wheel adapted for moving said yieldable member from said position of rest to said position of bending along said first predetermined path against the action of said spring means.

11. A timepiece movement according to claim 10, said starting up mechanism further comprising a fixed stud, a plate carrying said yieldable member and being provided with a slot adapted for cooperation with said fixed stud so as to guide thereby said plate both in translation and in rotation.

References Qited in the file of this patent UNITED STATES PATENTS 1,943,079 Kienzle Jan. 9, 1934 1,971,182 Hansen et al Aug. 21, 1934 2,108,931 Trepanier Feb. 22, 1938 FOREIGN PATENTS 369,386 Great Britain Apr. 8, 1929 484,219 Great Britain May 3, 1938 569,834 Germany Feb. 8, 1933

Claims (1)

1. IN A TIMEPIECE MOVEMENT, IN COMBINATION, A MOTION WORK, A SYNCHRONOUS MOTOR ADAPTED FOR RUNNING AT SPEEDS RANGING BETWEEN A MINIMUM AND A MAXIMUM VALUE, BUT HAVING A PREDETERMINED AVERAGE VALUE, FIRST MOTION TRANSMITTING MEANS INCLUDING A FIRST FREE-WHEEL MECHANISM AND CONNECTING SAID SYNCHRONOUS MOTOR TO SAID MOTION WORK FOR DRIVING THE SAME, A RESERVE MECHANISM ADAPTED FOR RUNNING UNINTERRUPTEDLY, AND SECOND MOTION TRANSMITTING MEANS INCLUDING A SECOND FREE-WHEEL MECHANISM AND CONNECTING SAID RESERVE MECHANISM TO SAID MOTION WORK FOR DRIVING THE SAME, SAID RESERVE MECHANISM BEING ADJUSTED SO AS TO BE ABLE TO DRIVE SAID MOTION WORK AT A PREDETERMINED SPEED LOWER THAN THAT AT WHICH SAID MOTION WORK IS DRIVEN BY SAID SYNCHRONOUS MOTOR, WHEN THE SAME IS RUNNING AT A SPEED EQUAL TO SAID PREDETERMINED AVERAGE VALUE, BUT HIGHER THAN THAT AT WHICH SAID MOTION WORK WOULD BE DRIVEN BY SAID SYNCHRONOUS MOTOR, WHEN THE SAME IS RUNNING AT A SPEED EQUAL TO SAID MINIMUM VALUE.

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