US2000585A - Electromagnetic impulse clock - Google Patents

Description

May 7, 1935. J. FINK K 2,000,585

ELECTROMAGNETI C `IMPULSE CLOCK Filed Aug. 23, 1932 wlmi i "l ya Il l,

Patented May 7, 1935 PATENT OFFICE ELECTBOMAGNETIC CLOCK `Josu Fink. Waltham, Mass... assigner' to Waltham 'Watch Company, Waltham, Mass., a cor-Peration of Massachusetts matin!! m 23. 1932, Serial No. 630,028

i This .iuvmtlon nelaias'to Atime pieces oct they *die in a driving spring is periodically rcwound ,by magnetic effected iby c1csi112 :the circuit of .an destro-magnet whenever a, predetermined proportion di the energy of the sprint has been enpemled. 4The object of meinnentienhssheen-tofurmshaclodrof this character possessing thecapability of long lite with `minimum deterioration thmngh many opelhns o! its :circuit controlling switch, and thenatnre of which lends itself to design in a Ime variety of different sizes and capacity for operation by currents of widely varying volt.- sits. That is, more sneciflcalhr, my aim has been to provide s clock suitable for use in auto# mobiles. 5er instance, operable by the low volt,- axe current of the storage battery such an automobile. and capable o functioning without derwssment nots/i the shocks and vibrations yto which ,it is subjected when carried by sn automobile; :whiierisie same design. with appropriate variations. may be embodied in mantel or v@weil vnud the like, operable by metric lighting currents and oliver currents crflcomperahly hizh. or hicher.\vol1tages. whether direct or alternating. Another object hmbeen to furnish a clock which, with s inin-r inmm cf change. may be connected in either an lulated electric ycircuit or in a grounded While `primarily designed tor paroisses above stated, the principles and essentials of thefwinventiqn are notlimited to use in a chock only, but are adapted for driving other Ehe new characteristics .of .the invention .include. among .other things, the `use of an encuedimvity switch 4morvcfhle angularly by and with the armature of an eleetromagnct, the use o! thesnme spring to serve both as a. leading in conductor for the switch and as -the main driv ing spring of the time pieee,'and`means including replaceable switch carriers for adapting the sometime' piecev for use either in an vinsulated circuit or aygrounded ch'cuit.

In the drawing.-

Fig. 1 is a rear elevation of the time piece showing r partielderly vthe electrical equipment;

2 is a horizontal section online 2.--2 of F11. l;

43 is .a partial rear elevation and partial Sectouon line 3-3 0I Figa; v

Fis. 4 is assction en linoM-f-G of Eig. `2;

Fis -5 is s Section amlrear elevation on the plane of line 5-5 of Fig. 2, shown on an enlarged scale;

Fig. 6 is a cross section on lined-6 of Fig. 5;

Fig. 'l is an elevation and partial section o! the switch carrier shown in Figs. 1 and 2";

Fig. 8 is a cross section of the same taken on line 8 8 of Fig. "7;

Fig. 9 is a view similarto Fig. l showing the arrangement of ythe apparatus adapted for use in a grounded electrical circuit;

Figs. 10 and 11 are sectional views of the switch carrier taken on line III-I0 and II-H' respectively of Fig. 9;

Fig. 12 is a perspective view of the associated disk and pinion which drives the clockr train through 4'the medium of a coupling spring;

Fig. 13 is an elevation of the coupling spring and the ratchet Wheel which applies tension thereto under impulsion by the main spring.

Fig. 14 is a view similar to Fig. 9 showingan added means for obtaining quick closing and openingof the switch;

Fig. 15 is a similar view ofthe switch showing it in open .circuit position;

Fig. '16 is an .elevation of the connector .he-k tween the switch carrier of Fig. 14 and the stai! of the amature.

Like reference characters designate the 4same parts wherever they occur in all .the figures.

The `electrical and magnetic equipment of my improved clock `comprises an electromagnet having pole kpieces 1II and I2, a wire coil I1, en armature i4, a svntch carrier I6, and a, gravity switch I6. The pole pieces are secured to s. holder plate I1 by posts Ill, Il, and 19,18, :to which nuts are applied. A vlaminated core 20 passing through the magnet coil or winding is secured by the .posts IB, I8 and the nuts thereon. A bridge y2I of non-magnetic material passes across the gap between the magnet poles at the opposite .side of thelatter from the plate l1, being positioned by the posts I9,` I9, and lsecured by nuts on yseid posts. This bridge :md `the plate lI1 rprovide 'bearings for a staff 22 .to which the armature il is secured. Said staff also protrudes beyond the bridge and supports :the switch .carrier I5.

Preferably the magnet pol have concave faces opposite to each other and vcquidistsnt from the stadi 22, and the amature is s. massive be.:` having .a length .nearly yas great as the .distance between these .opposed faces, so that it may rotate between them with .a air gan, hut .has .a substantially less width.`

The .switch carrier I5 is a block of insulating ture, and from each other.

magnet.

material preferably, although not necessarily, of cylindrical shape and of substantially the same diameter as the longer dimension of the armature. It may, however, be of any size and shape which enables it to occupy, and freely rotate in, the area between the coil I3, posts I9, I9, and the nearer part of the circumference of plate I1. It is secured to the staff 22 by a set screw 23 threaded through the base of a thimble 24 which is embedded in one side of the carrier.

The switch I9 in this embodiment is a mercury switch consisting of a glass tube containing a globule 25 of mercury, and in one end of which are sealed the ends of wires 2B and 21 which constitute the terminals of the switch. This tube is sunk into the carrier I5 from the end face thereof at one side of the pivot axis or staff and with its longer dimension tangential to an arc concentric with such axis so that, when the carrier is mounted with its axis horizontal, and is rotated, the mercury globule will roll or flow by gravity from one end to the other of the tube.

With the clock organized for connection in an insulated electric circuit, two spiral springs 23 and 29 are provided, secured respectively to posts 38 and 3| which are mounted on the plate I1 and project rearwardly therefrom. The posts may be insulated from the plate, or the springs insulated from the posts by any suitable means known in the art; the important fact is that both are insulated from the plate and other conductive parts of the clock struc- Spring 28 extends across the back or outer side of the switch carrier and is connected with a pin 32 which in turn is connected with the switch terminal 26 by a conductor 33. Spring 29 crosses the inner or front side of the switch carrier and is connected with a pin 34 which in turn is coupled electrically by a conductor 35 (Fig. 2) with the switch terminal 21. These pins are mounted in the switch carrier in any manner suitable to Yhold them with the rigidity necessary for performing their mechanical functions later described; and the conductors 33 and 35 are led to them from the switch terminals in any convenient manner, preferably being led and embedded in channels cut or pierced in the substance of the carrier. As this substance is of insulating material (at least as to that part of the carrier which holds the pins and conductors), the two pins and their conductors are insulated from each other.

One of the springs, as 29, is connected by a conductor 36 with one terminal of the magnet coil. The other spring and the other terminal of the coil are connected by conductors 31 and 38 to the opposite sides of a source of current, here represented conventionally as a battery 39.

The springs 28 and 29 are designed to serve also as main springs for driving the clock movement. They are therefore coiled in a spiral of several convolutions and are made of a substance, size and mass suitable for this purpose as well as for the ypurpose of carrying whatever current rnay be needed to energize the Alloys of copper, classed as bronzes, are known in the art which have ample hardness and resilience, as well as conductivity, for these purposes; springs of such an alloy. However, steel may be "used provided the springs are made with sufand I prefer to make these cient sectional area to carry the current. They are also put under tension, or partially wound up before the clock is put into service; which may be done by rotating the holder I5 on the staff before the set screw 23 is tightened up to clamp it. When set up ready for service, the parts are so placed that the springs exert tension counterclockwise on the armature I4, tending to hold it in a position crosswise of the lines of magnetic force, where it is arrested by a. pin 44, which is carried by the armature, engaging one end of an arcuate slot in the plate I1; and the switch is then in the position shown in Fig. l with its end which contains the terminal contacts enough'lower than its other end to insure location of the mercury globule in that end and in contact with the switch terminals.

To equip the clock for grounded circuit use, the spring 28 is removed and the switch contact 26 is grounded on the framework. This change may be most easily made by substituting for the switch holder I5, an equivalent switch holder I5a which is identical with it except in that the contact 21 is coupled by a conductor 46 with the metal socket 24 wherein set screw 23 is seated; and the circuit connection is continued through such set screw and the staff 22 to the frame of the clock. The contact 26 is connected by conductor 33 with pin 34a which projects from the forward side of the switch carrier for connection with spring 29 and passes through the substance of the carrier far enough for connection with said conductor. This arrangement is particularly suited to clocks designed for use in automobiles, where the frame of the clock movement, and one pole of the storage battery, are grounded on the frame of the automobile, the other pole of the battery being coupled by an insulated conductor with the magnet coil I3, and the latter and spring 29 being also insulated from the frame. The clock movement consists of the usual gear train and balance escapement, the members of which are mounted between a pillar or front plate 41 and a back plate 48, and/or a bridge or bridges of any suitable design. That is, the clock movement may be like any spring driven movement, or of any other suitable design, except that the usual main spring of such clock is omitted. Energy for driving the movement is furnished by the springs 28 and 29, or the single spring 29 when only one is used, transmitted from the armature I4 by the pin 44, previously mentioned, which projects through the slot 45 (which is concentric with staff 22) in the plate I1, and a registered slot in plate 48 to connection with a driving member 49 for the clock movement. This connection is a permanent one Such driving member is here made as a disk rotatable about a staff 50 mounted in the plates 41 and 48 in alinement with staff 22. It drives through a one-way clutch consisting of a ratchet wheel 5I, also rotatable about the same staff, and a pawl 52 connected to theldisk by a pivot stud 53 and pressed upon by a spring 54, which also is connected to the disk by a screw 55. A coupling spring 56 for continuing the driving effort while the mainspring is being wound, made as a spiral of several convolutions surrounding staff 50, is contained in a recess in the ratchet Wheel and connected at one end thereto by means of a pin 51, and at the other end to a pin 51a which projects into the recess from a disk 58, which is so mounted on the staff as to overlie said recess. This spring is made of Bucient .length to ive the clock for an extended time, for ce half an hour or more, to Mold necessity of resetting the clock if the eussent supply should fall temporarily. A pinion il is made fast to stal i0 and drives the conter wheel of the clock time train through midle pinion 6I which turns about a pivot stud anchored in the plate 4%.

It will now be apparent that when themagnot is enengized, by closing of the switch when the annature occupies a position wherein its valor dimension is transverse to the magnetic lines of force. the armature is given a sudden impulse im clockwise rotation (with respect to the drawing) which is powerful enough to give it momentum sufllcient to carry it to the limit of movement imposed by structural parts of the device; such movement being in the construction shown nearly Thus the Vdriving pawl i2 iscam'ied backward around the rim of ratchet wheel il, which is prevented from turning with it, by a holding pawl 'B2 pivoted to a stud 63 and pressed toward the ratchet by a Aspring 6,4; said pivot stud and spring being secured to plate n Switch holder Ii is turned at the same time, andassoonastbecirciutisbrokenbythe mercury globule falling away from the terminal contacts, the magnetic flux ceases, leaving the armature free to be carried by its momentum beyond the position where it receives the greatest concentration of magnetic lines of force. Atthe same time the springs 28 and 29, or spring il when 2B is omitted. are put kunder increased tension which, together with theinitial tension, is imply sumcient .to drive the movement. When, in the course of the rotation imparted by such spring or springs (occurring. in the counter-clockwise direction with respect to the drawing) the pin 44 nearly reaches the end of slot .45, and the amature is brought crosswise to the field of the magnet, the switch arrives in position for completing the circuit; and the 'previous action is repeated.

It is desirable, when the clock is used in an automobile, to prevent the joltingand vibration of the automobile from throwing the mercury globule against the terminal contacts prematurely, as it might when the switch has nearly attained a horizontal position but has not turned far enough for the globule to pass by gravity into circuit closing position. To prevent this I provide an obstruction or baille -65 in the casing of the ,switch (which is most conveniently made by lndenting the side of the glass tube when softened by heat) so located and designed as to hinder displacement of the globule by jolting, while permitting its displacement by gravity when the switch is in the proper position. But this. while a desirable feature, is not essential; and 'it ls unnecessary in connection with a clock provided for use where it is not subjected to any considerable vibration.

The fact that the switch is mounted off center from its axis of revolution is a useful feature, as it causes the momentum of the globule, imparted by its rapid revolution under the magnetic impulse, to carry it forcibly away from the terminal contacts and insure opening of the circuit when the armature is arrested at the end of its swing. Such arrest occurs in this design when the pin M brings up against the end of paul i2, kbut it may .equally well be caused by the and of slot li.

Al'urthcr means for eectingsudden opening and closing of the circuit, which may be und withv the means just described, or alternatively theretmis shown yinliigs. 14-16. yIt comprises mounting the switch carrier with capacity for angular motion independently of the armature. impelling it by the armature with provision :for lost motion, and giving it an increment of angular movement, suddenly applied, when the cinna-` ture nears the end of its swing in each direction.

In the embodiment illustrated, which is applied to the grounded circuit arrangement of the electrical apparatus, the switch carrier li is mounted loosely on the armature staz 22, and a plate or disk 66 is mounted `fixedly on the staff. One of the springs 28 or 29, or its .equivalent, here designated as 28a, is coupled to the plate 66, or to the staff so as to have the same mechanical functions previously described. It does not, however, have any electrical function. Two or more springs may be so used if desired.

The switch carrier is provided with a. M'

which projects into a notch 68 i-n the disk Si, serving as a coupler by which the disk propels the switch carrier in both directions, and .providing for an angular lost motion of yany ydesinotl amount. I have found in practice that anangle traversed when arriving in that position; and

when the switch and armature are near the opposite ylimit of oscillation (Fig. 15) the pull of the spring is at the opposite side of the axis and exerts turning movement in the opposite direction. In the course of the rotation .of the armature in either direction the pin 10 crosses the dead point and the direction of turning moment applied by spring 69 von the switch carrier is reversed.

The eifect of the spring 28a or its equivalent, like that'of the springs 28 and 29, is to rotate the staff in counter-clockwise rotation, turning the disk 66 from the position shown in Fig. l5 to that shown in Figs. 14 and 16, and the disk then impels the switch carrier by the 'boundary 1I of notch 68 acting on pin 61. This pin, yand also pin 10, are angularly so related to the switch or circuit closer that when the latter is 4thus brought to a, horizontal position, or nearly so,

and While the mercury globule is still in the end of the tube remote from the terminal contacts, the pin 10 is brought past the dead point, whereupon the spring instantly advances the switch carrier through the Vangle of lost emotion', which is made great enough to insure gravity.

displacement of the mercury globule into circuit closing position. Movement of the mercury is also expedited by its momentum and the sudden arrest of the switch carrier when pin 6! brings up against the opposite boundary 12 of the notch. The disk 66, being then turned in clockwise rotation by the magnet armature, propels the switch carrier yby means yof the .bounding edge 12 until the pin 10 passes the dead point again, and spring 69 then suddenly gives .the

switchk carrier its incremental angle of lost mo-l tion in the clockwise direction. Sudden arrest of the switch carrier again occurs when thepin 61 reaches the boundary 1l; and the inertia eff.

fects resultingtherefrom are cumulative of those due to arrest of the armature. Thus closing and opening of the circuit are positively insured, and possibility of any of the mercury remaining in bridging connection across the switch terminals is definitely excluded. The mercury is forcibly propelled over any obstacle, such as the balile 65, which may be provided to prevent premature closing of the circuit due to jolting of the clock.

It will be understood that the directions indicated in the foregoing description as clockwise and counter-clockwise have reference to the present illustration, which shows the electrical equipment in rear elevation, and are not to be confused with the actual direction of rotation of the hands of the clock with which this motive mechanism is used.

In the arrangement just described the spring 69 forms part of the electric circuit, being in circuit with the conductor 36 and with pin lll, which in turn is coupled by a conductor 2'3 with one of the switch terminals, the other terminal being connected by a conductor ld with a metal bushing l5 in the switch carrier which surrounds stair 22. When used in an insulated or nongrounded circuit, the connection 'i4 is led to an external contact on the switch carrier with which a stationary brush in the circuit makes contact. It is to be understood that the spring 69, while strong enough to give the incremental angular movement to the switch carrier herein described, may be much weaker than the main spring 28a, so as not to aiicct appreciably the functioning of the latter.

While I have described the member 65 as a disk, it will be understood that the outline and angular extent of this member is unimportant, provided only it subtends a large enough angle to provide abutments, as TI and l2, between which an impulse member, as the pin 5l, on the switch carrier may play with the desired lost motion.

The use of a switch of the closed type is conducive to long life, for its tube or casing is preferably lled with an inert gas, or it may be exhausted to a high degree of vacuum. Thus oxidation is entirely avoided and sparking largely eliminated. With low voltage currents the sparking is not serious enough to need any consideration. It can be eliminated, or greatly diminished with currents of any voltage by including a condenser in the circuit. I have not shown such a condenser herein, because its use for that purpose is too well known to require explanation.

With suitable selection and design oi the electrical parts, according to principles well understood by electricians, clocks may be made according to the principles herein disclosed for use with any voltage practicable for general use, and with either direct or alternating current. Such clocks, once properly regulated, will run without attention for very long periods and with only minute consumption of current.

It will be understood that while I have described a mercury switch as the preferred circuit closer in this combination, I am not limited to mercury as a mobile element of the closer, but may use a ball of solid conductive matter, or a liquid conductor other than mercury. Within certain aspects of the invention I may also use other types of gravity switch.

. What I claim and desire to secure by Letters Patent is:

1. In a clock impeller of the character described, an electromagnet having oppositely disposed poles, an armature rotatably mounted on an axis midway between said poles and having arms of greater length than width extending oppositely from the axis, a switch carrier secured to the stan of said armature to be carried and rotated thereby, a spiral spring coiled around the axis of said armature coupled at one end to said switch carrier and anchored at its opposite end, and an enclosed mercury switch or circuit breaker mounted on said switch carrier to be tilted with rotation of the carrier and having separated terminal contacts at one end, one of said contacts being in electrical connection with the spring.

2. A clock impeller of the character described comprising a rotatably mounted magnet armature, a magnet having poles embracing said armature and adapted when energized to turn the latter from a position of greater reluctance to another position of less reluctance with respect to the magnetic field, a switch carrier secured to the staff of said armature to be rotated thereby, a mercury switch comprising a closed tube containing a globule of mercury, closed at both ends, mounted at one side of said steil with its length dimension tangential and having separated terminal contacts in one end, pins projecting from opposite faces of said switch carrier and each being separately in electrical i connection with one of said contacts, coil springs on opposite sides of the switch carrier surrounding said stail, each mechanically and electrically connnected at one end to one of said pins and being mechanically anchored and electrically insulated at the other end, and electrical connections betwecn said springs and the magnet winding and source of current respectively.

3. An electro magnetic impulse apparatus comprising an electro magnet having an oscillative armature, a spring tending to rotate said armature into a position of greater than minimum magnetic reluctance, a driven member impelled by said spring, a gravity circuit closer in the circuit of the electro magnet, a carrier for said circuit closer rotatable about a horizontal axis, coupling means having an angular lost motion for rotating the switch carrier from the magnet armature, and means for rotating the switch carrier ahead of said impelling means when it approaches circuit closing position.

4. In a clock of the character described, a revolubly mounted circuit closer having a mobile conductive element gravity impelled to circuit closing or circuit opening position according to the position of the device about a substantially horizontal axis, an electromagnet having an armature mounted rotatably between the magnet poles with capacity for rotation through an angle of the order of means comprising separated abutments connected for rotation by and with said armature and a projection from the circuit closer embraced between said abutments with provision for angular lost motion, a spring acting on the armature tending to place it in a position of greater than minimum reluctance with respect to the field of the magnet, and means for suddenly advancing the circuit closer into circuit closing position when advanced near to such position by one of said abutments under the impulsion of said spring.

5. The combination with an electromagnet, of

an armature rotatably mounted between the poles of said magnet, yieldable impelling means acting on said armature and tending to return it to a position of greater than'minimum reluctance with respect to the magnet field from a positien'cf minimum reluctance with respect to such field, a member yhaving angularly separated abutments secured to said'armature for angular movement by and with the same, a switch having 'a 'gravity impelled circuit kclosing element mounted to turn about a horizontal axis, a projection from said switch located with capacity for vlost motion between said abutments and adapted to be driven by one or the other of said abutments with rotation of the armature in respectively opposite directions, a spring coupled with said switch carrier at a pointeccentric to its axis of revolution so that the line of its force application is shifted from one side to the other y of the axis of rotation as the switch carrier is advanced in either direction by one or the other of said abutments.

6. In an electromagnetically impelled clock, the combination of an electromagnet, a rotatable armature for said magnet, a spring connected to said armature and tending to place it in a position of greater than minimum reluctance to the magnetic field, a coupling between said armature and the clock movement for driving the latter, a switch carrier rotatably mounted co-axially with said armature and having a mercury switch in circuit with the magnet field, the axis of the armature and switch being horizontal, separated abutments connected and movable with the armature, a projection from the switch carrier embraced by said abutments and having capacity for lost motion between them, a spring coupled to said switch carrier to exert force at an eccentric point thereon toward the axis of the switch, but in a line extending past the axis on one side and then the other side thereof in the course of the armature-impelled movement of said carrier.

7. An electromagnetic impulse motor comprising an armature, a switch carrier, and a driving member, all mounted oscillatively on the same axis and mechanically connected together, an electromagnet having poles embracing said armature, and the amature having a greater mass of magnetic material in one diameter than Ain any other diameter, an electric switch comprising an air excluding tube mounted on the switch carrier containing separated contact terminals in one end and a mobile circuit closing body adapted to shift into and out of contact with said terminalsl as the switch carrier is rotated to one position or another, a driving spring coiled around said axis, having a mechanical connection at one end with the before named oscillative members and a stationary anchorage at its opposite end and being under tension such that it tends to place the armature in a position where the diameter which contains the greatest magnetic mass is transverse to the magnetic eld, a stop co-operating with the spring to establish such position of the armature, the switch being then located with the end which contains said contact terminals lowermost, whereby the mobile body is caused by gravity to close the gap between them, and the armature being movable under magnetic impulse from said position through an arc wide enough to tilt the switch so that the mobile body shifts out of engagement with said contact terminals, and a one way clutch operable by the driving member to transmit motion under the impulsion oi' said spring.

8. An electromagnetic impulse motoras set forth in claim 7 in which said spring is oi electrically conductive material and is in electrical connection at one end with the eld winding rof the electromagnet and at its other end with one h of said contact terminals, thefother of said terminals being otherwise connected in the same circuit.

9. An electromagnetic impulse motor asset forth in vclaim '7 ycomprising two springs supported and arranged substantially as set forth, each being connected at one end separately to one of said contact terminals, and being connected at their opposite ends separately in opposite sides ci an electric circuit, and the iield winding oi the magnet being connected in one side oi' the same circuit.

i0. An electromagnetic impulse motor comprising a magnet armature, a switch carrier and a driving member mounted to oscillate about the same axis, the armature and driving member being rigidly connected together and the switch carrier being independently oscillatable, connections between the switch carrier and armature organized to drive the former positively in each direction with capacity for a limited degree of lost motion, a magnet having poles embracing said armature, a spring connected to the armature tending to place the armature in a position of greater than minimum reluctance with respect to the magnetic eld and a stop coacting therewith for so positioning the armature, the spring being put under increased stress by movement of the armature effected by excitation of the magnet, a spring connected to the switch carrier and arranged to hold the latter at one limit of its lost motion when the armature is in the before mentioned position of reluctance, and to shift the carrier to the other limit of its lost motion when the armature is displaced by magnetic impulsion, an electric switch carried by said carrier comprising a hermetically sealed tube having separated terminal contacts in one end and a movable circuit closing body, mounted on lsaid carrier in such position that the movable body is brought against said contacts when the armature is in the before named position and the switch carrier is at the rst of the above named limits of its lost motion, the movable body being displaced from contact when the armature and carrier are moved by magnetic action.

11. An electromagnetic impulse motor as set forth in claim l in which the switch is mounted eccentrically with respect to the carrier, whereby its movable circuit closing body is given momentum in the course of the lost movtion of the carrier and the switch tube is arrested suddenly at each limit of such lost motion.

12. An electromagnetic impulse motor as set forth in claim 10 in which the spring for effecting the lost motion movements of the switch carrier is an electrical conductor and is electrically connected with one of said contacts in a circuit which includes the other contact and the winding of the electromagnet.

13. An electromagnetic motive apparatus comprising an electromagnet, an armature for said magnet rotatably mounted between the poles thereof and movable from a position of relatively great reluctance with respect to the field of the magnet to and through a position of minimum reluctance when impelled by magnetic Y iiux, two springs coupled to said armature and Vfil) both acting to exert torque on the armature in the same direction, tending to return the armature to the rst named position after displacement therefrom, means including a one Way clutch in rigid connection with said armature for transmitting motion from the armature when the latter is so actuated by said springs, and a gravity circuit closer having separated terminals each in separate electrical connection 10 with one of said springs; the springs being in circuit between its said terminals when the ar mature is in and near the first named position, and to break the circuit when the armature is in the position of minimum reluctance.

JEAN FINK.

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