US2091117A - Electric clock - Google Patents

Description

Aug. 24, 1937. A. w. HAYDbN 2,091,117

ELECTRIC CLOCK Filed June 1, 1934 5 Sheets-Sheet 1 F I R :2 a;

Z6 Z6 I AZ? 2 #30 3 .34 I 36' 0'! 7 INVENTOR BY L w M ATTORNEYS Aug. 24, 1937. A, w HAYDQN 2,091,117

ELECTRIC CLOCK Filed June 1, 1934 3 Sheets-Sheet 2 V ATTORNEYS A. w. HAYDON ELECTRIC CLOCK Aug. 24, 1937.

Filed June 1, 1934 5 Sheets-Sheet 3 INVENTOR ,zwa7 wa, 4?

ATTORNEYS Patented Aug. 24, 1937 UNITED STATES PATENT OFFlCE This invention relates to improvements in time-instruments; and particularly to improvements in that class of electrically driven timeinstruments known as the maintaining-power" 6 type, which are normally driven synchronously by an electric motor, but upon failure of the power supply to the electric motor, may automatically operate for a considerable period of time from an auxiliary power device.

10 There is a large class of instruments, such as clocks, recording devices and switching devices, which utilize timing mechanisms either continuously or intermittently in the course of their operation. Such instruments may be referred to 15 as time-instruments"; and their driven elements, such as the clock hands, recording drums, and switching drums or any part thereof, may be referred to as a time-element". It has been 25 motors, is greatly impaired by the fact that the time-elements of such instruments do not function during interruptions of the electric power supply. Though such interruptions are not generally long in duration or frequent in occurrence, they are extremely objectionable. For example, if the instrument is a clock, unless it is reset by hand upon resumption of the electric power supply, the time indication will thereafter be inaccurate by an amount corresponding to the interval of current interruption; or if the instrument is a switching device, operation will be delayed by the same interval; or if a recording device, the record will be interrupted during that interval.

However, other features of electrically-driven time-instruments, such as their accuracy during normal operation'and their freedom from any need for regulatory adjustments, have so strange ly recommended their use that it has been pro-' 45 posed to provide such time-instruments with 50 power time-instruments. In order that frequent inspection of the condition of the auxiliary power devices in such instruments shall not be necessary, it has also been proposed to provide means by which energy from the primary electric motor 55 may automatically be stored .in the, auxiliary power device during normal operation, in order that such device may be kept in continual readiness to'assume the burden of operating the instrument immediately upon interruption of the electric power supply to the primary motor. Means have also beensuggested by which the auxiliary power device shall automatically assume the driving function upon interruption of the primary power supply, and relinquish the driving function upon resumption of the primary power supply.

In general, however, maintaining-power timeinstruments heretofore proposed have been impractical becauseof their complexity of construction, with consequent mechanical unreliability and expense of manufacture. ne difficulty has been the supposed necessity of providing a gear train for supplying energy to the auxiliary power device, and another gear train for discharging and regulating the discharge of the auxiliary energy during interruptions of the primary power supply, in addition to the usual synchronous gear train through which the time-element is I normally driven by the electric motor. It is an object of my invention to simplify the mechanism of maintaining-powertime-instruments by providing such an arrangement of the several parts that a gear train forming a part of the mecha-' nism through which power is normally transmitted from the electric motor to other parts of the instrument, may be utilized during operation from the auxiliary power device, thus eliminating the necessity for providing a separate gear train for operation from the auxiliary power device.

The foregoing object may be accomplished by the provision of means by which a portion of the mechanism through which the time-element or driven member or mechanism is normally driven by the electric motor may be reversed upon failure of the electric power supply and serve as a driving train from the auxiliary power device. Means may also be provided for regulating the operation of the auxiliary power device through said reversed gear train.

Another objection to many constructions heretofore proposed, is that the escapement provided for the regulation of operation from the auxiliary power device positively controls the movement even when-the instrument is operating normally from the primary elect whereby are lost the great benefits of synchronous electrical operation. In other constructions in which the escapement exercises no positive regulatory function during operation of the instrument from the primary electrical supply, it may be so coupled to the vsynchronous train that any serious maladjustment of the escapement causes injury to the escapement or interferes with synchronous operation of the time-instrument. In constructions which obviate the above difiiculties by providing for the entire disengagement of the escapement mechanism during synchronous operation, the condition of the escapement mechanism may become im-. paired by disuse, or the quiescent condition of the escapement may render it somewhat slow in assuming its regular function when the primary power supply fails. It is an object of this invention to provide a coupling through which the escapement mechanism may exercise a regulating function only when the instrument is operating from the auxiliary power supply, and through which the escapement mechanism may be continuously agitated during normal opera;- tion, to keep the same in good working order for auxiliary operation.

With this object in view I provide an escapement coupling which is substantially unidirectional, in that it slips when the gear train is driven in the normal direction by the electric motor, but transmits to the gear train a regulating torque when the gear train is driven in the reverse direction by the auxiliary power device. Another object is to provide means for indicating to an observer whether the instrument is being operated from the primary electric power supply or from the auxiliary power supply. The means which I provide for accomplishing this object comprises 'an element positioned outside the mechanism, but directly driven by that portion of the gear train which is reversed during operation from the auxiliary power device; thus, the indicating means shows by its direction of rotation whether the instrument is being driven by the .motor or by the auxiliary power supply.

Another object is to provide in my improved arrangement means for automatically disconnecting the electric motor and other idle parts from the mechanism during operation by the auxiliary drive. Thereby the load upon the auxiliarypower device may be reduced and a longer period of operation therefrom made possible.

The various objects of my invention will be more apparent upon considering the following detailed description of certain embodiments thereof. This description is to be taken in conjunction with the accompanying drawings in which:.

Fig. 1 is a side elevation of a clock embodying my invention, the concentric arrangement of the shafts which bear the clock hands being shown in cross-section, and the escapement mechanism being omitted;

V Fig. 2 is a vertical sectional view taken on the plane denoted by the line 2.2 of Fig. 1;

Fig. 3 is a horizontal sectional view taken on the plane denoted by the line 3--3 of Fig. 1;

Fig. 4 is the side elevation opposite that of Fig. 1, showing in section the escapement clutch; Fig. 5 is a vertical sectional view taken on the plane denoted by the line 5-5 of Fig. 1;

Fig. 6 is a front elevation showing the parts in front of the front frame plate, a portion of the gears being broken away to show the relation of other gears therebehind;

Fig. 7 is.a vertical sectional view taken on the plane deno'te d by the line 1-10: Fig. 4;

Fig. 8 is .an expanded diagram showing the parts of the mechanism in their operative relationships;

Fig. 9 is an enlarged sectional view showing details of the arrangement of the concentric shafts which bear the clock hands;

Fig. 10 an enlarged sectional view of the main spring and attachment, showing details of.

construction;

. Fig. 11 is a sectional view taken along the plane denoted by the line I l--H of Fig. 10, showing details of construction; and

Fig. 12 is an expanded diagram showing an alternative embodiment of my invention.

Similar numerals refer to similar parts throughout the several figures of the drawings.

The clock mechanism is supported by the usual front and rear frame plates 25 and 2 I, respectively, rigidly held in spaced relation by the columns 22. On the outside face of the rear frame plate 2! is attached the stator 23 of a synchronous .electric motor having a rotor 2d mounted on a plate 2| is the worm 25 which engages the worm wheel 21 attached to the arbor 28. Also attached to the arbor 28 is worm 29 which normally engages worm wheel 35 on the arbor 3i. Secured to the arbor 3! are the collar 32 and the pinion 33, between which elements is the collar 35 loosely mounted on the arbor 3| so as to be rotatable with respect thereto. A spring 35 is loosely wound about collars 32 and 34 in a man ner hereinafter described in detail.

Attached to the collar 34 is the escapement wheel 36 with which may be associated any suitable escapement mechanism. Illustrated in Figs. 5; 7, and 8 is one such mechanism in which the wheel 35 is engaged by the detent member 31 pivoted at 39 and bearing a counterbalanced lever 38. One end of the lever 38 is bifurcated and embraces a pin 48 slightly .ofiset from the balance staff 40 at the center of the balance wheel 42. Associated with the balance wheel 62 is the usual hairspring 33 attached at its inner end to the balance staff 40 and at its outer end to the block II on the rear frame plate 2|. Associated with the hairspring 43 there may be provided any well known means to shorten or lengthen the effective length of the hairspring for regulating purposes. The pinion 33 engages a gear wheel 44 attached to the arbor 45, to which are also attached the sweep-second hand 46 of the clock, the pinion 41, and the eccentric 48. The eccentric 48 is embraced by the prongs of a bifurcated element 49 attached to a rotatable shaft 50, which passes through the front frame plate 20. Mounted on the shaft 50 outside of the front frame plate 20 is a rocker 5i having a pair of pawls 52, which successively engage the ratchet wheel 53 to rotate the minute and hour hands 54 and 55, respectively, of the clock through a suitable gear train comprising gears 56, 51, 58, 59, G0 and GI. The position of the clock face is indicated on Fig. 1 by the dotted element 11. The clock hands 46, 54 and 55, or any of them, may be characterized as a time-element or as the driven member of a timing mechanism. The auxiliary power device is a spring 68 which is connected ;to the pinion 41 through a suitable gear train comprising gears 62, 63, 64, I5

is secured to the shaft 69 in any suitable manner as by the pin 10. As shown in Figs. and 11, the outer end of the spring v68 is provided with a slot 13 which engages a notch 14 in the connector 15. The connector 15 is rigidly attached to one end of the clutch band 16 and is movably engaged by a slot 12 in the other end -of the clutch band. The clutch band 16 consists of .a single loop of resilient material bowed into frictional contact with at least a part of the inner 15 surface of barrel 61 Means suitable for disengaging the rotor of the electric motor when the current falls areshown in connection with the worm 29 and wormwheel 21 hereinbefore described. As illustrated 2,0 in Figs. 1, 2, 3 and 4, these gears may be borne 25 plate 2!.

vention illustrated in Figs. 1 to 8 inclusive, is

by an arbor 28 pivoted at its ends in a U-shaped member 19. The member 19 issupported by a as follows:

The electric motor may be of any type which operates at a fixed speed commensurable with the requisite speed of the device to be driven.

Preferably, it. is one of the self-starting synchronous type, which operates'from an alterhating current source having a frequency which is maintained very close to aflxed average value. When the electric motor is energized, the rotor 25 bearing the worm 26 is driven at synchronous speed. Through a gear train comprising gears 21, 29, 30, 33 and 34, worm 26 drives shaft 45 in a clockwise direction at the rate of one revolution per minute. This rotation is indicated by the sweep-second hand 46 of the clock.

The revolution of the eccentric 48 with shaft 45 imparts to the bifurcated element 49 a cyclic oscillatory movement through a small arc. motion is transmitted through the shaft 56 to the rocker 5| which bears the double-acting pawls 52. These pawls being pivoted at opposite ends of the rocker 5|, they alternately advance and recede, engaging the ratchet wheel 53 in succession to rotate it almost continuously.

The movement of, the ratchet wheel 53 is transmitted through the usual gear train comprising gears 56, 51, 56, 59, 60, and 6|, to the minute and hour hands 54 and 55, respectively.

-Theimportant functional feature of this eccentric-and-ratchet mechanism is that it transmits to the clock-hands a clockwise rotation independent of the direction of rotation of the gear train which drives the eccentric. It is apparent that any other means which perform that function may be substituted for the mechanism shown. The auxiliary power device for operating the instrument upon failure of the electric supply, may be any suitable energy-storing device, such as a spring or a weight system; In this embodiment, I have shown a suitable spring mechanism for the purpose. Here, the rotation of the pinion 41 serves to rotate the barrel 61 through the gear train comprising gears 62, 63, 64, 65, and 66.-

This

is also rotated in the same direction because of its frictional engagement with the inside surface of the barrel. This movement of the clutch band 16 is transmitted through the connector- 15 to the outer end of the spring 68. Since the inner end of the spring is fastened to the shaft 68* which is normally fixed against rotation, the rotation of the outer end in the driven direction winds the spring.

It is desirable to provide means to prevent 'overwinding of the spring 68 during prolonged operation of the electric motor. The means shown in Figs. 7, 10, and 11 are suitable for this purpose. As the spring 68 becomes tightened, the outer end acts through the connector 15 to draw the ends of the clutch band 16 away from the inside surface of the barrel. This decreases the area of contact between the clutch band 16 and the inside surface of the barrel 51 until, when the spring is fully wound, the area of contact is so reduced that the clutch band slips on the inner surface of the barrel, thus preventing further tightening of the spring 68.

It is apparent that since the shaft 69 serves no function in the operation of the timing mechanism, and is subject to a continual torque from the spring 68, means may be provided for periodically releasing the shaft 69 to operate a striking or alarm device of any common type.

Upon failure of the electric supply to the motor, the tension on the spring 68 almost instantaneously overcomes the inertia of the gear train comprising gears 66, 65, 84, 63, 62, it, it, 33, and 30, and causes the gear train to reverse its rotation. The reversal of the gear 4? on shaft 45" causes the sweep-second hand 46 to rotate in a counter-clockwise direction, thus indicating to any observer that the electric power has failed and the clock is then operating from the energy of the spring. However, this reversal of the sweep-second hand does not affect the continued clockwise rotation of the minute and hour hands, because those elements are driven through the eccentric-and-ratchet mechanism previously described.

. When the electric power supply fails, it is gen-- erally necessary to include in the mechanism some means for regulating the movement. Any well-known means for this purpose may be utilized, and I have shown a suitable lever escapement comprising the escapement wheel 36 cooperating with a detent 31, a counter-balanced lever 38, and a balance wheel 42 with a hair spring 45 and pin 4|, operating in the usual manner.

To avoid any control by the escapement mechanism over the normal operation of the electric motor,' I provide the novel clutch arrangement best shown in Figs. 4 and 8. The helical spring 35 is loosely wound about the collars32 and 34 in such a direction that when the collar 34 is driven in the normal direction of rotation by the electric motor, the spring tends to loosen on the collars, allowing them to slip with respect to each other. The escapement wheel 36 may be constructed in such a way that it may be driven backwards; then, under the slight fric-' tion of the loosened spring the escapement wheel will slowly rotate backwards, keeping the detent and balance wheel in gentle agitation, ready to instantly assume a regulating function when the electric power supply fails.

When the electric power supply fails, the direction of rotation of the collar 34 is reversed,

and the spring 35 then tends to tighten about the collars 32 and 34. The retarding effect of the detent 31 maintains the spring at a tension,

locking the collars.32 and. 34 together, and per- I mitting the transmission ofa regulating torque through the spring. It is thus seen that I have provided a coupling which is substantially irre versible in that it is incapable of transmitting a regulating torque except during reverse rotation ary power device, thus prolonging the period for which the auxiliary 'power device will operate following the failure of the electric power. Especially is it necessary to remove from operation all worm gears which are non-reversible. A suitable means for accomplishing this purpose is shown in Figs. 1, 2, 3, and 4. .In this device, when the stator of the electric motor is energized, it draws the rotor 24 forward as indicated by the arrow on Fig. 4. This axial displacement of the rotor causes a corresponding displacement of the projection 18 which bears against the end of the shaft 25 on which the rotor 24 is mounted.

The displacement of the projection 18 swings the suspension device forward to bring the gears 29 and 30 into engagement, as shown in Figs. 1 and 3, thus driving the synchronous gear train from the electric motor. However, when electric power fails, the suspension device and the rotor are drawn rearward by the spring 83 into the position indicated by the solid lines in Fig. 4. This disengages the worm gears 29 and 30, removing them from operation until power is'restored and the rotor draws forward into its normal position.

In Figs. v1 and 9 there is shown the concentric arrangement of the shafts which bear the clock hands and the gears 51, 58 and ti. -A feature of this arrangement is the independent center Hill which consists of a hollow pin staked to the front frame plate 20, and carrying on its inside the shaft 45 and on its outside the concentric shafts which bear the hands 54 and 55. To avoid excessive friction on the shaft 45, the inside of the independent center may be made somewhat larger than the shaft 45 except at the forward end where a bearing is provided. The use of the independent center I00 lends rigidity to the entire structure in front of the front frame plate 20, and prevents undue frictional load being placed on the shaft 45 by the other shafts. The latter advantage is of especial importance when the clock is being driven by the auxiliary spring 68.

From the foregoing description of the opera- 7 tion of a clock embodying my invention, it is apparent that the entire gear train, with the exception of the worm gears 26, 27, 29 and 30, is utilized whenever the clock is in operation, whether driven by the electric motor or by the auxiliary power device. .This construction dispenses with the duplicate gear train for auxiliary operation and makes possible a maintaining-power clock having only a few more parts than a clock not having the maintaining-power feature, thus affording a marked contrast with spring 94 as it is stretched by speed.

the complicated mechanism previously employed in such time-instruments. It will be noted that in the apparatus described above the gear train comprising gears 33 and 44 operates in one direction when driven by the motor and in the opposite direction when driven by the auxiliary power device.

Fig. 12 shows another embodiment of my invention in which 24' is the rotor of a synchronous electric motor driving a shaft 45 through a gear train comprising gears 26', 21, 29', 3B, 33, and 44'. Mounted on shaft 45' are the pinion 41', the eccentric 48, and the sweep-second hand 48, which correspond to similarly numbered partsof the embodiment previously described. Eccentric 48 drives the parts numbered 49- to 61, inclusive, in the manner previously described. Pinion 41' Winds the spring 68' through a gear 62 mounted on the shaft 69. The barrel 6'! in this embodiment is held stationary, except when released to operate an alarm or striking device of some common type. In connection with the spring 68' may be provided suitable means to prevent overwinding, for example, means such as are shown in Fig. 10, above described.

' A feature of this embodiment is the use of a regulator which is effective to limit the rate of operation of the clock when operated from the which are connected by the spring 94 which is attached at its center to a pin 95 at the center of disk 90. A stationary brake-band 96 of magnetic material such as soft iron surrounds the moving elements. Whenever the shaft 25' is rotated in either direction, centrifugal force will cause the fly-elements 92 to swing outwardly about the pivot points 9!, until the centrifugal force is balanced by the restraining force of the such outward movement. The spring 94 is so adjusted that the fly-elements 92 do not quite engage the'brakeband 96 when the device is rotating at its normal Consequently, the device performs no function during normal operation from the primary electric motor. However, when the instrurnent is operating from the auxiliary power device there may be some tendency to overspeed. Whenever such condition occurs, the increased centrifugal force causes the magnetized fly-elements 92 to move outwardly to frictionally, engage the brake-band 96 of magnetic material. There results a deceleration in the speed, but because of their magnetic adherence to the magnetic brake-band 96, the magnetized flyelements 92 continue to adhere' to the brakeband, until a speed slightly below normal is reached, at. which point the fly-elements under the tension of spring 94 disengage the brakeband. The brake-band may be split and its ends may be joined by a screw 91. By adjusting this screw the diameter of the brake-band 96 can be increased or decreased, thus regulating the speed at which the magnetized fly-elements will engage and disengage the brake-band.

' 35 claims.

The average speed over a period of time may by this means be kept approximately normal when the instrument is operating from the auxiliary power device. I In this embodiment it is seen that all oi the parts are in operation whenever the clock is operating from either the electric motor or the auxiliary spring.

It is thus seen that the economy of parts and simplicity of construction made possible by my invention may be accomplished by providing an arrangement by which-at least a portion of the main-driving gear train may be reversed upon failure of the primary power supply, and be utilized to perform driving and regulating functions which have hitherto required auxiliary gear trains. Such an arrangement provides without any additional parts an indicator to show whether the device is operating from electrical 29 power or from the auxiliary power device. In such an arrangement, also, it is possible to solve the regulating problem simply by providing a coupling which efiectively engages the escapement mechanism only during operation of the gear train in the reverse direction under auxiliary drive. Further, it. is feasible to provide an auxiliary power device which has only a single connection to the rest of the mechanism in that it both receives and discharges its auxiliary en- 39 ergy through a single gear train. v My invention is not limited to the particular embodiments thereof illustrated and described in detail herein, but includes such modifications thereof as fall within the scope ofthe appended For example, though I have specifically described a clock embodying my invention, it is apparent that my invention is equally applicable to other devices, such as recorders and time switches, which utilize a timing mechanism. 40 I claim:

1. In a deviceof the type described, a member to be driven, an electric motor, means, including a gear train, arranged to drive said member in a single direction, regardless of the direction of operation of said gear train, said gear train being normally driven in one direction by said motor to transmit power to .said member and an auxiliary power device for driving said gear train in the reverse direction during cessation of operation of said motor.

2. In a device of the type described, a member to be driven, an elect ic motor, means, including a gear train, arranged to drive said member in a single direction regardless 'of the direction of operation of said gear train, said gear train being normally driven in one direction by said motor to transmit powerto said member, an auxiliary power device for driving said gear train in the reverse direction during cessation of operation 0 of said motor, said means being arranged to supply said auxiliary power device with energy from said electric motor during normal operation. I 3. In a device of ,the type described, a member to be driven, an electric motor, means, including a gear train, arranged to drive said member, said gear train being normally driven in one direction by said motor to transmit power to said member, said means also including means for imparting to said member a unidirectional rotation regard- 7 less of the direction of operation of said gear train, and an auxiliary power device for driving said gear train in the reverse direction during cessation of operation of said motor.

4. In a device of the type described, a member 7 to be driven, an electric motor, means, including i with said gear train for regulating the speed a gear train, arranged to drive said member, said gear train being normally driven in one direction by said motor to transmit power to said member,

- said means further including an eccentric-andratchet mechanism for imparting to said member 5 a unidirectional rotation regardless of the direction of rotation of said gear train, and an auxiliary power device for driving said gear train in the reverse direction during cessation of operation of said motor.

5. In a device of the type described, a member to be driven, an electric motor, means, including a gear train, arranged to drive said member regardless of the direction of operation of said gear train, said gear train being normally driven in one direction by said motor to transmit power to said member, means for automatically uncoupling said motor from said gear train upon cessation of operation of said motor and an auxiliary power device for driving said gear train in the reverse direction during cessation of operation of said motor.

6. In a device of the type described, a member to be driven, an electric motor, meanaincluding a gear train, arranged to drive said member in a single direction regardless of the direction of operation of said gear train, said gear train being normally driven in one direction by said motor to transmit power to said member, means associated thereof, and an auxiliary power device for driving said gear train in the reverse direction during cessation of operation of said motor.

'7. In a device of the type described, a member to be driven, an electric motor, means, including a gear train, arranged to. drive said member in a single direction regardless of the direction of operation of said gear train, said gear train being normally driven in one direction by said motor to transmit power to said member, an auxiliary power device for driving said gear train in the reverse direction during cessation of operation of said motor and a rotatable indicator associated with said gear train whereby it rotates in one direction while said motor is operating and in the opposite direction during cessation of operation oi. said motor.

8. In a device of the type described, a member to be driven, an electric motor, means, including a gear train, arranged to drive said member regardless of the direction of operation of said gear train, said gear train being normally driven in one direction by said motor to transmit power to said member, a regulating mechanism for regulating the operation of said gear train, an auxiliary power device for driving said gear train in the reverse direction during cessation of operation of said motor, and means responsive to the direction of rotation of said gear train for coupling said regulating mechanism to said gear train during operation of said gear train in the reverse direction.

9. In a device of the type described, a member to. be driven, an electric motor, means, including a gear train, arranged to drive said member 55 regardless of the direction of operation of said gear train, said gear train being normally driven in one direction'by said motor to transmltpower to said member, a regulating mechanism for regulating the operation 01 said gear train, mauxiliarypower device ior'driving said gear train in the reverse direction during cessation of operation of said motor, and means responsive to the direction of rotation 01 said gear train for coupling said regulating mechanism to said gear /i train during operation of said gear train in the reverse direction, said coupling means comprising a collar driven by said gear train, a collar positioned adjacent to said driven collar and coaxial therewith for driving the regulating mech-' ber in a single direction regardless of the direction ofoperation of said gear train, said gear train being normally driven in one direction by said motor to transmit power to said member, a regulating mechanism for regulating the operation of said gear train, an auxiliary power device for driving said gear train in the reverse direction dining cessation of operation of said motor, and means for coupling said regulating, mechanism to said gear train during operation of said gear train by the auxiliary power device.

11. In a device of the type described, a member to be driven, an electric motor, means, including a gear train, arranged to drive said memher in a single direction regardless of the direction of operation of said gear train, said gear train being normally driven in one direction by said motor to transmit power to said member, and an auxiliary power device including a spring, for

driving said gear train in the reverse direction during cessation of operation of said motor, said gear train being connected to said auxiliary power device to Wind said spring while said gear train is being driven by said motor.

12, In a device of the type described, a member to be driven, an electric motor, means, in-

cluding a gear train, arranged to drive said memher in a single direction regardless of the direction oi operation of said gear train, said gear train being normally driven in one direction by said motor to transmit power to said member, an auxiliary power device for driving said gear train in the reverse direction during cessation of operation of said motor, and a reversible driving connection between said gear train and said auxiliary power device, whereby energy is supplied to said power device from said electric motor during normal operation.

13. In a device of the type described, a mem ber to be driven, an electric motor, means, including a gear train, arranged to drive said member, said gear train being normally driven by said motor to transmit power to said member, an auxiliary power device for driving said gear train during cessation of operation of said motor and a regulator for regulating said gear train, said regulator comprising a plurality of magnetized fly-elements centrifugally actuated by the rotation of said motor and a magnetic brake-band to frictionally engage said fly-elements when the speed of the device becomes higher than normal, and disengage said fly-elements when the speed of the device is reduced below normal by such frictional engagement.

14. A continuously rotating clock regulator comprising a magnetized fly-element, a spring centripetally restraining said fiy-element, a

brake-band of magnetizable material to frictionally engage said fly-element at speeds higher than normal and to disengage said fly-element when the speed has been reduced below normal.

ARTHUR WILLIAM HAYDON.

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