US2019898A - Electric clock - Google Patents

Description

. W 9 1935' J. FINK 2,019,898 I ELECTRI C CLOCK Filed Feb. '20, 1951 Patented Nov. 5, 1935 ELECTRIC oLoo Jean Fink, Waltham, Mass., assignor to Waltham Watch Company, Waltham, Mass, a corporation of Massachusetts Application February 20, 1931, Serial No. 517,238

8 C aims- This invention relates to electric clocks of the type wherein the power is provided by electric current, in discontinuous impulses, which are applied to store power in a spring by which the timing train and time indicators are directly driven.

Its primary object is to improve the circuit making elements of the apparatus in order to insure a good contact between the separable members thereof whenever they come into engagement.

Other objects are to furnish improvements in the construction and operation of the mechanical and electrical equipment or" the clock, as explained in the following specification and pointed out in the claims. The invention consistsin the new characteristics thus described and all equivalents thereof within the scope of the claims.

The embodiment of the invention chosen for illustration herein is a clock designed for installation and. use in an automobile to be driven by power derived from the storage battery of such automobile. Hence the detailed description which foliowsiis given in terms of such use and environment, but in the understanding that the scope of the invention and of the protection hereinafter claimed are not limited to the details of construction thus shown and described, or to the specific uses indicated.

In the drawing,

Fig. '11s a rear elevation of an automobile clock closing case or housing being removed;

Fig; 'Zis anel'evation, or under plan, as seen frombeneath Fig. 1;

Fig; 3 is a rear elevation of the clock from which 3- the electro-magnetic equipment has been removed; b 4 is a view similar to Fig. 2 of the clock by 1' se Fig. 5 is a sectional view taken on line 55 of Figs. 1 and 3, and shown on an enlarged scale;

Fig. 6 is a sectional elevation taken on line 66 of Fig. 5 -showing the impelling part of the .electro-magnet and the impulse receiving pin of the afiywheel;

Fig. .7 is a rear elevation of the impulse receiv: :ing flywheel and'the associated pawl and ratchet smeansdriven thereby;

Fig. 8 is afront elevation of the impulse receiv- .inglflywheel andpower storing springof the clock 50 movement;

Fig. 9 is a detail sectional view of the magnet .arrnaturelor rotor and associated parts.

' Like reference characters designate the same parts wherever they occur in all the figures. ll l represents the pillar plate of a clock movemade in accordance with this invention, the enment, to the forward side of which the dial is secured and to the rear of which are connected back plates or bridges l3, l4, and a balance cook 15 for supporting and positioning the usual train wheels i8, ll, i8, etc., balance wheel i9, and 5 escapement of a standard watch or clock movement. The pillar plate is adapted to receive detachably a case or housing enclosing the working parts; and the entire assemblage is adapted to be mounted in the instrument board of an automo- 10 bile according to standard practice, or in any other desired location in any desired way.

To the back of the clock movement is secured, V

by screws 29, a base plate 2| on which the electrical equipment is mounted. Such equipment 15 comprises an electro-magnet having coils 22 and. a core terminating in poles 23, 2e, and an armature 25. The poles are recessed on their adjacent sides to bound in part a circular space in which the armature is centrally pivoted and rotatable. The 20 armature is secured to a staff 26 which has a bearing atone end in the base plate 2i and at the other end in a bridge 27 at the rear of the pole pieces, which crosses the space between their terminals and is secured to them by attaching screws. The armature 25 is a bar of steel or iron having greater length than Width and of which the length is slightly less than the Width of the space between the magnet poles pieces, so that it can swing freely between their faces. It has increased thickness or 30 mass at the ends, in the form of flanges 23, whereby it is strongly attracted into alinement with the poles when the magnet is energized. It is connected with a spring 29 which tends to displace it to a position where its length is transverse, at an inclination, to the magnetic lines of force between the magnet poles. In short, the armature is constantly under the influence of yielding force tending to place it where it offers a relatively difficult path for lines of magnetic force but permitting it to move thence to a position wherein it permits a greater concentration of lines of force. A feature of the invention resides in the details of the specific assemblage herein shown of the armatur e,its carrier, and other associated parts; although in its broader aspects the invention is 7 notlimited thereto. Describing these details, the armature is mounted on a metal sleeve 38) which is fitted friction tight on the staff or arbor 26 through a lining sleeve or bushing 3! of insulating material, by which it is insulated from the arbor. The armature is centrally apertured and fits over one end of sleeve 30, which is there reduced in diameter, resting on a contiguous shoulder of the sleeve, and on a radially protruding 55 flange 32. It is secured tightly, in a manner permitting ready assemblage and easy adjustment, by a clamp plate 33 which surrounds the sleeve and is drawn tightly against the opposite side of flange 32 by screws 34, passing through the armature and threaded into the clamp plate. Spring 29 is coiled in a flat spiral around the sleeve 35, and is clamped near one of its ends against the side of the sleeve by a clamp plate 35 secured by screws 35. This clamp plate is also a holder for an impelling arm or cam wiper 31 which has mechanical and electrical functions later described. Preferably the clamp plate and impeller are made out of one piece of sheet metal thick enough to be essentially stiff, the impeller being bent outward from one edge of the plate 35, substantially radially to the sleeve 30, but with a certain backward curvature for a purpose later described.

Spring 29 is part of the electric circuit of the magnet, and impeller arm 31 is a circuit breaker in electrical contact with the spring but otherwise insulated from the clock movement by the insulating bushing 3!, except when it engages its complemental circuit making and breaking contact member. By virtue of the clamp plate 35 a good electrical contact is made between the spring and impeller arm, while at the same time a simple, convenient and eificient means of mechanically attaching the spring to the armature is provided. Although the spring is also in electrical contact with the metal sleeve 35 and the armature, these parts are isolated electrically from the other metallic parts of the clock by the insulating bushing 3I.

The outer end of spring 29 is anchored and clamped to the side of a block of insulating material 38 on the base plate, by a screw attached strap 39, to which also is coupled, by a screw 40, the end or" a conductor 4| which leads to one terminal of the magnet coil. The other terminal 42 of the coil or winding is connected to a binding post 43, insulated from the clock movement.

The complemental member of the make-andbreak device, and the receiver of impulses delivered by the impeller 31, is a pin or stud 44, or equivalent conductive abutment, protruding across the path of the impeller arm 31, through a curved slot 45 eccentric to staff 26 in back plate I3, from a flywheel 46 which occupies with freedom for rotation a circular recess, formed partly in said back plate and partly in the pillar plate I I, and is centered therein by a staff 41 having pivot bearings, concentric with slot 45, in the back plate I3 and in the pillar plate. The arrangement of these parts is such, as is best shown by Fig. 5, that the axis of the armature lies between the axis of the flywheel and the path in which the pin 44 travels; in other words, it is surrounded by the circumference of which such path is a part. The flywheel has a massive rim from which stud 44 projects, a central hub 49 surrounding staff 41, and an intermediate connecting web 5|! between them, which is set inward from both end planes of the rim to provide recesses or chambers at both sides of the web.

In the recess of the flywheel next to the pillar plate is placed a volute spring 5| surrounding the hub 49 and connected at one end to the web 50 by a pin 52, while its other end is connected to the pillar plate by a pin 53. This is the main, or power, spring. In the recess at the other side of the web is a ratchet wheel 54 surrounding and rotatable on the staff 41. The teeth of this wheel are engaged by a driving pawl 55 and a holding pawl 56. The driving pawl is pivoted to a stud 51 mounted in the web 55, and is pressed toward the ratchet by a spring 58 secured to the pawl and reacting against the rim of the flywheel. The holding pawl is pivoted on a stud 59 which projects from the back plate I3 and is pressed toward the ratchet by a spring 68 which reacts on the plate. This pawl and ratchet mechanism is one form of a one-Way clutch through which the power of the main spring is transmitted to the clock movement and with which the flywheel is coupled and periodically recoupled, as later described. Other equivalent types of clutch may be used in place of the one thus illustrated, within the scope of the invention.

Rotatably mounted on the staii 4'! independently of ratchet 54 are a pinion 62 and a disk 63, rigidly secured to one another. A spring 64 is located between this disk and the ratchet, being connected at one end to the former and at the other end to the latter. Pinion 52 drives the time train of the clock movement through an inter mediate gear 65 (Fig. 3) which meshes with the pinion 52 and the center wheel I6 of the time train and is pivoted on a stud mounted on the inner side of the back plate I3.

The clock when designed for use with an automobile, is put into connection with the storage battery of the automobile as the source of power, and may be mounted in such a way that the clock frame or movement is grounded on the metal framework of the automobile, while the binding post 43 is connected by an in sulated conductor with the positive pole of the battery. But of course other sources of current and other modes of connecting the clock therewith may be used, as is well understood by those skilled in the electrical arts. The important fact is that the magnet winding and the flywheel are so coupled in an electrical circuit that whenever the impeller 37 and the stud 44 make contact, a circuit is made which energizes the electro-magnet; and when the arm and stud separate, such circuit is broken and the magnet is deenergized.

When the magnet is made active in this way, the armature is strongly and suddenly turned from its position of rest, shown in Fig. 1, in

- clockwise rotation with respect to Fig. 1, and in so moving it carries the impeller arm 31 from the position shown by full lines, to that shown by dotted lines, in Fig. 6 driving the impulse receiving pin 44, and putting the main spring 5I under greater tension. The momentum given to the massive armature by its rapid motion tends to carry it beyond its position of greatest concentration of magnetic lines of force, and if it were not otherwise arrested, it would overswing and return. Also the momentum of the flywheel tends to continue its motion after the armature begins to swing back, and the pawl 55 prevents it from returning when its momentum is expended, except at the slow rate permitted by the rate of running of the time train. In the absence of any other arresting means, these actions are suflicient to separate the contact members 31 and 44, whereby the magnet energizing circuit is broken. But I prefer to limit the swing of the armature by a stop pin 66 in the path of the impeller arm which checks the arm and causes it to rebound away from the contact stud. Such arrest takes place before the arm has turned far enough to pass I by to the other side of the stud; as it might do if allowed to continue unchecked, unless it were made of otherwise unnecessarily great length.

The impeller arm is somewhat curved backward, as previously stated, in order to compensate to some extent for the acceleration of the armature and the increasing distance of the impulse stud from the axis of the armature. That is, the impulse stud and flywheel are driven at more nearly a uniform rate than they would be if the arm were not thus curved. Upon the breaking of the circuit, the armature and impeller arm are returned by the biasing spring 29 to normal position.

The flywheel, in being so rotated, puts the main spring under increased tension and carries its pawl 55 into engagement with a more advanced tooth of the ratchet. It is quickly brought to rest and rotated in the reverse direction by the main spring 5|, imparting motion to the clock movement through the ratchet 54, spring 64 and pinion 62. Its movement in this direction continues until it makes contact again with the arm 31, when the action above described is repeated. These actions continue indefinitely as long as electrical current is supplied.

The coupling spring 64 is provided in order to continue the driving force to the time, train without interruption when the flywheel is impelled to wind up the main spring by the magnetic motor. In transmitting the full power needed for driving the train, this coupling spring is flexed and put under tension, whereby it stores up enough energy to keep the clock running during the brief periods when the main spring is N disconnected from the ratchet wheel in being wound up by the magnetic motor. And the ratchet is withheld by its holding pawl 55 from backward movement by either the reaction of the coupling spring or the traverse of the flywheel and its coupling pawl.

The rate of running of the clock is independent of the speed of the magnetic motor or the frequency of its operation, and is controlled in the same way as in any spring driven clock by the balance wheel and escapement. A regulator 61 which controls the effective length of the hair spring, in the manner usual with clocks having lever escapements, is provided with a toothed segment in mesh with a segmental pinion 68 secured to a shaft 69 which passes through the back of the enclosing case and carries a knob or index by which it may be turned to regulate the running of the clock. Another shaft it, which also protrudes through the back of the case and carries a knob or the like, is provided for setting the hands in a well known way.

I have not shown the clock movement in further detail because the invention is not'concerned with a clock movement as such, but rather with a new electrical means for developing power from a source of electric current to drive a time piece of any desired character. I

may say also that the invention may be embodied in other clocks than those applied to automobiles and supplied with power from other sources than a storage battery and may be coupled with the source of power by other conductors and modes of connection than those here described. The new steps in which the invention particularly resides are not dependent on either the time train or the source of power. The current may be direct or alternating, taken from a battery, generator, or any other suitable source.

. One of the important features of this invention is the combination and cooperation of the members of the circuit making and breaking device. These members, being also the transmitters of mechanical force, are operated so that the active face of the arm 31 wipes across the abutment member 44, with a rubbing action due to the relative eccentricity of their paths, so that the contact surfaces of these members are continually kept clean and bright and in good condition for instantly completing the circuit whenever they come together with even a light contact. Preferably the normal position of rest of the impeller arm is across the slot 45 near one end thereof so that it is touched by the contact stud before the latter reaches the end of the slot. Thus if a good contact fails to be made at the first touch, the continued movement of the stud causes it to rub on the arm and insure completion of the circuit before it is finally arrested. Another advantage of this arrangement is that, owing to the location of the armature axis between the abutment pin M and the axis of flywheel 6 when the latter is in position to receive a spring winding impulse, the contact point on the impeller arm is at a very short distance from its axis. This distance in fact is less than the length of the arms of the armature 25. Thus the impeller arm is enabled to apply a very powerful initial thrust in overcoming the inertia of the flywheel and in winding the main spring. At the same time the impulse may be continuously applied through a full 90 of swing of the armature, as here shown, or further if desired, without making the impeller arm excessively long.

Another feature is the combination in one element (the spring 29) of the function both of a conductor for supplying current to the make-andbreak device and a biasing spring for placing and normally holding the armature in its inactive position. And still other important features are included in the construction of the armature and its associated parts previously described.

Permanence in the qualities and condition of the spring 29 and the circuit making and breaking elements is essential to the continued running of the clock without attention. In order to insure these qualities in the highest possible measure, I make the spring 29 preferably of phosphor bronze, nickel plated, which is resilient, resistant to corrosion, and a good conductor; and I make the impeller arm 3'! and the complemental stud M preferably of molybdenum, as this material is hard and does not readily oxidize. However, this statement of preference is not in any sense a limitation of the range of substances which may be used.

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

1. In an apparatus of the character described, an armature, spring, and impeller assemblage comprising a pivoted carrier, a bar-like magnet armature secured frictionally to the carrier with provision for angular adjustment about the axis thereof, a spiral spring coiled around said carrier, and a clamp plate secured to said carrier in a manner to grip the spring against the side of the carrier, said spring and clamp plate being of electrically conductive material and the clamp plate having an outstanding impeller arm.

2. In a clock apparatus of the character described, a bar-like magnet armature having a central opening, a cylindrical carrier body, one end of which enters said opening, said carrier having a flange at one side of which the armature is placed, a clamp plate at the opposite side of said flange from the armature, and connecting means for forcing the armature and clamp plate toward one another and gripping said flange between them.

3. In a clock apparatus of the character described, a bar-like magnet armature having a central opening, a cylindrical carrier body, one end of which enters said opening, said carrier having a flange at one side of which the armature is placed, and a clamp plate at the opposite side of said flange from the armature and having a hole in which the body is received, but which is of smaller diameter than the flange.

4. In an electric clock having an electro-magnet, an armature mounted to oscillate between the poles of said magnet, a biasing spring coiled around the axis of the armature in electrical connection with the magnet winding, one end of said spring being stationarily anchored, and an impeller arm of electrically conductive material secured to the armature so as to project laterally from the pivot axis thereof and having a portion made a clamp securing the other end of the spring to the armature and making conductive contact with the spring.

5. An electro-magnetic motive apparatus of the character set forth comprising an electro-magnet, an armature mounted to oscillate on an axis between the poles of said magnet, a biasing spring coupled to said armature tending to place the latter in a position where it offers a relatively difiicult path for lines of magnetic force while permitting it to move thence to a position where it permits a greater concentration of lines of 3 force, an impeller forming one member of an electric make and break device in circuit with the winding of said magnet constructed as a wiper arm in substantially radial relation to the axis of the armature, an abutment forming the complemental member of such make and break device mounted to rotate about an axis eccentric to that of the armature in a path of longer radius than such eccentricity and in a position crossing the plane in which said impelleris constrained to travel, and a power spring coupled with said abutment so as to resist displacement of the latter by the impeller and to drive the abutment in the opposite direction when the latter is out of contact with the impeller; said abutment and the axis about which it travels being on respectively opposite sides of the armature axis when the abutment comes into circuit making contact with the impeller.

6. In an electro-magneiic motive apparatus, the combination with an electro-magnet having an armature oscillatively mounted on an axis between the magnet poles and spring biased so to occupy a position transverse to themagnetic lines of force between said poles when the mag net is deenergized, of an abutment'mounted to move revolubly in a path which is an arcof'a curve surrounding the axis of the armature} an impeller arm carried by the armature'protrud ing radially from the axis thereof imposition to apply driving force to said abutment when the magnet is energized, and a spring connected to said abutment so as to apply force tending to revolve the abutment in the opposite direction to that caused by the impeller.

7. In an electro-magnetic motive apparatus, the combination with an electro-magnet having an armature oscillatively mounted on an axis between the magnet poles and spring biased so as to occupy a position transverse to the magnetic lines of force between said poles when the magnet is deenergized, of an abutment mounted to' revolve in a curved path, the center of which is eccentric to the armature and the continuation of which throughout a complete circuit surrounds said axis, a spring connected with said abutment tending to place the latter in that part of its path where it is at the opposite side of the armature axis from its own center of revolution, and an impeller arm carried by the armature and projecting in a generally radial relationship to the axis thereof, at the same side of the armature axis, when in the normal biased position of the armature, as the last named position of the abutment.

8. In an electro-magnetic motive apparatus, the combination with an electro-magnet, an ar mature rotatably mounted on an axis between the magnet poles and a biasing spring normally holding the armature in a given position when the magnet is deenergized, of an impeller arm carried by the armature and protruding in a generally radial relationship to the axis thereof, an abutment revolubly mounted to rotate about a center at the opposite side of the armature axis from the normal biased position of said impeller arm, and being spaced away from said center by a distance greater than the distance between said center and the armature axis, the abutment being located across the path in which the impeller arm is moved by rotation of the armature,

so as to be propelled thereby, and a spring couo pled with the abutment to resist its propelled movement and to drive it in the opposite direc-' tion toward the normal position of the impeller arm.

JEAN FINK.

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