US2260525A - Electric clock - Google Patents

Description

Oct. 28, 1941.

Original Filed April 28, 1939 39 If a2 J. W. HOBBS ELECTRIC CLOCK 2 Sheets-Shet 1 um Ila/Hobbs Oct. 28,1941. w HOBBS 2,260,525

ELECTRIC CLOCK Origin al Filed April 28, 1939 2 Sheets-Sheet 2' n/ofin WHObbS Patented Oct. 28, 1941 2,260,525 ELECTRIC CLOCK John W. Hobbs, Springfield, Ill., assignor to John W. Hobbs Corporation, Springfield, 111., a corporation of Delaware Original application April 28, 1939, Serial No.

270,523. Divided and this application November 13, 1939, Serial No, 303,984

11 Claims. gel. 1s5 11) The present invention relates in general to electric clocks of the type adapted for use in connection with vehicles, such as automobiles, and is more particularly concerned with springactuated clocks which are arranged to be automatically wound by an electrically actuated rewinding mechanism.

The present application constitutes a division of my co-pending application, Serial No. 270,523, filed April 28, 1939.

In general, clocks of this type embody a ratchet wheel which is connected with the main driving shaft of the timing mechanism and arranged to be actuated through suitable pawls carried on a movable armature by a tension spring connected to the armature. The pawls engage the ratchet wheel for driving it in a forward timing direction. Associated with the armature is a suitable electro-magnet for actuating the armature to a new position for tensioning the driving spring, whenever the driving spring has reached a predetermined unstressed condition.

The rewinding of the clock is usually automatically accomplished by means of a switch arranged to be actuated in response to the movement of the armature; so that, as the armature reaches a position in which the driving spring is in a substantially unstressed or rundown condition, the switch is snapped to closed position to energize the electro-magnet and return the armature to a position wherein the driving spring is again stressed, and in which the spring may again operate to drive the timing mechanism. At this position, the movement of In the present invention, it is a primary object to provide novel and inertia controlled means for opening a main control switch in the energizing circuit of the electro-magnet of the rewind mechanism, and which will act to operate the switch especially when there is insuificient voltage to move the armature to a position corresponding to fully stressed condition of the main driving spring.

A further object of the herein described invention is to provide in connection with a main the armature operates to open the switch and demagnetize the electro-magnet.

While such an arrangement works satisfactorily under maintained voltage conditions, conditions may prevail when operating the clock from a storage battery of an automobile which will result in unsatisfactory operation of the rewinding mechanism. For example, when the voltage of the battery of an automobile is below normal, or during starting of the car, particularly in the winter time, there may be times when there is insufiicient voltage to energize the electro-magnet sufliciently to move the armature to a' position wherein it will open the deenergizing switch in circuit with the electromagnet winding. Under such conditions, the electro-magnet winding will be energized for an abnormal period of time, with the result that the coil of the electro-magnet becomes overheated and there is the possibility of its being burned out or otherwise damaged.

Various devices for opening the circuit under such conditions have been suggested, such as thermostatically operated switches, fuses and the like.

control switch for the rewinding mechanism, novel resetting means for actuating the switch contacts to closed position, wherein the resetting operation is mechanically motivated in response to relative movements between the armature and an inertia member carried by the armature.

Other objects and features of the invention will more fully appear from the detailed description, taken in connection with the accompanying drawings, which illustrate a single embodiment thereof, and in which:

Figure 1 is a side elevational View of a clock mechanism embodying the features of the present invention, when looking toward the circuit controlling switch of the rewinding mechanism;

Figure 2 is a transverse sectional view showing the position of the armature as it approaches its limit position corresponding to a substantially unwound condition of the main driving spring, the control switch contacts being in open position;

Figure 3 is a view similar to Figure 2, the armature having reached a position corresponding to a substantially unwound condition of the main driving spring and the contacts of the main control switch having been actuated to closed position;

Figure 4 is a similar view showing the positions of the control switch mechanism and the armature, when the rewinding mechanism has been fully energized and the armature moved to a position in which the driving spring is fully stressed, the main control switch contacts having been moved to open position;

Figure 5 is a similar view showing the operation of the inertia controlled means for opening the control switch contacts, when the rewinding mechanism has not been energized sufficiently to completely rewind the main driving spring;

As shown 'on the drawings:

Referring to Figure 1, the mechanism of the present invention is mounted on a frame structure comprising a back plate ill, a front plate II, and an intermediate plate I2, these plates being supported in spaced-apart relation by suitable distance pieces 13 arranged to maintain the plates in rigid assembled relation. The frame structure also forms a support for conventional timing mechanism (not shown) including a geartrain for actuating the hour and minute hands in proper speed ratio, and a conventional escapement mechanism (not shown) for controlling the operation of the driving mechanism.

The timing train is associated with a shaft [4 which is rotatably suppoltedin the plates. and provideswith a spring friction connection !5 for engaging the surface of a gear l6. This arrangement is conventional and permits sets ously described is considerably'simplified over the ting movements of the timing gears and hands with reference to the driving mechanism. The

gear I 6, which is drivingly connected with a conventional escapement mechanism, is driven by means of a ratchet driving wheel ll.

This ratchet wheel, as shown in Figure 4, is arranged to be actuated in one direction by a pair of push-pawls l8 and I9 carried by an ar mature 20. This armature embodies a pair of radially extending arms 2! and 22 in angularly disposed relation. The armature is provided with a suitable hub portion which pivotally' supports the armature on the shaft 14 for rotative move ment. j s

The armature arm 2| is provided with aprojecting portion 23 which has one end of a main driving spring 24 connected thereto as shown at 25, the other end of thisdriving spring being anchored to the intermediate plate l2 as shown at 26.

It will be noted that the main driving spring is so arranged that, when the armature is rotated in a clockwise direction as viewed in Figures 2, 3 and 4, the spring will be tensioned and the pawls l8 and i9 will ride 'over the peripheral teeth of the ratchetwheel ll. Rotation of the ratchet wheel in the same direction as the armature is being moved during the rewinding operation is prevented by'means of a detent pawl 21 pivotally mounted on the back plate l0 and provided with aflsuitable spring for actuating it into engagement with the ratchet wheel teeth. 3 When the armature is released, the pawls i8 and I9, by virture of their engagement with the teeth on the ratchet wheel, will carry the ratchet wheel with them as the driving mechanism is moved under the force of the main driving spring 24. This driving operation is, of course, controlled by the escapement mechanism in the usual manner. i

Provision is made for electrically actuating the armature in a direction to tension the main driving spring, that is, to move the armature in a clockwise direction as viewed in Figures 2, 3 and 4. For this purpose, there is disposed for operative association with the armature an electro-magnet having an energizing coil 28 wound on a suitable magnetic core, This core is fitted at each end with a pole piece 29, the pole pieces of the respective ends being operatively associated with armature poles'3ll-3B respectively formed at the ends of the armature arms 2| and 22. The electro-magnet thus formed is secured to the front plate H as by suitable rivets 3| which extend through the plate and engage the pole pieces of the electro-magn'et. It will be noted that the intermediate, plate I2 is discontinued to provide space for the electro-magnet, and that the electro-magnet projects past the intermediate plate and has its opposite side disposed adjacent the back plate Hl.

Movement of the armature away from the electro-magnet poles, that is, during the driving operation of the timing mechanism, is lime usual. construction, and that the depth of the timing, mechanism may be decreased by virtue of having the armature arms disposed in angular relation so that the electro-magnet may be placed at one side of the driving shaft 54. This construction eliminates the necessity of the usual practice of having to discontinue the driving shaft directly over the electro-magnet or provide for its passage through the coil and core thereof.

'For controlling the actuation of the rewind-' ing mechanism, a switch assembly is provided in the space between the front and intermediate frame plates H and 12. As shown in Figures 2, 3, 4 and "5,'the switch assembly includes a pair of contacts 33 and 34which are arranged for relativemovement to closed and opened relation. The contact ismounted adjacent one end of a flexible strip 35, the contact being at the free end of the strip. The strip 35 is anchored at its other end between suitable insulating members which are supportingly mounted on a bracket post 35 secured to the intermediate plate. s i

The contact 33 is actuated by a multi-armed lever having a pivotal mounting as shown at 31 on the intermediate plate and comprising the angularly disposed arms 38, 39 and 40, the contact 33 being carried at the free end of the arm 43. r

The arm 38, at its outermost end, is bifurcated to provide a V- notch 4!. Associated with this notch is another arm 42 which is pivoted at one end for swingingmovement in a post or bracket 43 on the intermediate plate. At its other end, the arm 42 is provided with a beveled head portion 44 defining a knife edge-arranged to seat inthe V-notch 4|. A spring 45 surrounds thearm 42 and extends from the head portion of the arm to the post bracket 43. This spring acts to resiliently maintain the V-head' in engagement'with the'V-n'otch of the arm 38 and provides a toggle mechanism for moving the multi-armed lever with a snap action in opposite directions from the deadcenter position in which the arms 38 and 42 are in axial align: ment.

Means are provided for swinging the multiarmed lever in response to movements of the armature during the driving and rewinding operations. Closing of the contacts 33 and 34 is accomplished by providing a pair of substantially radially aligned spaced-l-apart pins 46 and 41 on the armature, thesepins being arrangedto successively engage the arm 39 during rotational movement of the armature in a counterclockwise direction while driving the clock, as shown in Figures 2, 3 and 4; The pins 46 and 41 are arranged to relatively move the contacts 33 and 34 to a position in which they will be snapped into engagement, as the armature approaches run-down condition of spring 24, at which time the armature is approaching its limit of counterclockwise movement against the stop 32. As soon as this position'of the armature is reached and the contacts 33 and 34 are closed, the rewinding operation is ready to take place.

Closure of contacts 33 and 34 complete a .circuit to the actuating coil 28 of the electro-ma'gnet. This circuit may be from a source of power, such as a storage battery 48, as shown in Figure 3, which may have one of its terminals connected by a conductor 49 directly with the clock frame, or the conductor 49 may connect with the frame through a ground circuit. The other terminal of the battery is connected through a conductor 50 to one end of the actuating coil 28, the other end of this coil being connected through a suitable conductor to the contact supporting strip 35. The circuit then continues through the contacts 33 and 34 to the multiarmed lever which is connected from a point adjacent its pivot by a bridging conductor 52 to the post 43 which is in grounded connection with th clock frame, from whence the circuit is carried back through the frame structure to the conductor 49 or the other side of the battery.

The actuating coil being energized functions to attract the armature, moving it in a clockwise direction. This movement of the armature acts to again tension the main driving spring 24.

Provision is made for opening the contacts 33 and 34 by resetting the movable contact 33 to open position relative to contact 34. Referring to Figures 2, 3, 4, and 5, an arm 53 is disposed adjacent the armature 20, this arm being supported for pivotal movement at its innermost end of the shaft l4, and provided at its outermost or free end with a weight 54. This arm is connected with the armature for limited swinging movement relative thereto, a pin 55 on the armature projecting into an elongate opening 56 in the arm substantially intermediate its pivoted end and its free end. Adjacent the slot 56, the arm 53 is provided with an angularly projecting portion 51 having a pin 58 which normally lies on the opposite side of the arm 39 from the pins 46 and 41 carried by the armature. A light spring 59 is secured at one end to the armature arm 22 and has its other end bearing against the free end of arm 53, so that this spring normally acts to rotate the arm 53 in a clockwise direction until the pin 55 has reached the right end of the elongate opening 56, thus limiting the movement of the arm by the spring 59.

The position of the control parts are shown in Figure 2 with the armature approaching the limit of its counterclockwise driving movement, the control switch having its contacts in open position. Continued movement of the armature brings the armature pins 46 and 41 successively against the arm 39 to actuate the multi-lever through dead-center and snap the switch con tacts to closed position, as shown in Figure 3.

As soon as the armature begins to move in a clockwise direction, there will be a lag in the movement of arm 53 due to its inertia. This lagging movement will cause the arm 53 and the arm 22 of the armature to swing together and compress the spring 59. In the event that the battery has sufficient voltage to move the armature to fully stressed condition of the main driving spring 24, as shown in Figure 4, the movement of pin 58 will carry it into engagement with the arm 39 and move the multi-lever in the opposite direction through its dead-center position, whereupon the contacts 33 and 34 are snapped to open position by the action of spring 45.

During times when the battery is partially discharged or when starting the car in cold weather, there may be insufficient voltage to completely operate the rewinding mechanism by movement of the armature to fully stressed condition of the main driving spring 24, and the armature may only move part way as shown in Figure 5. With the initial movement of the armature, the arm 53 will act due to its inertia to compress the spring 59 as previously explained. As soon as the armature has traveled as far as possible, with the low voltage excitation, cessation of the armature movement will permit the arm 53 to swing in a clockwise direction about the shaft 14 under the action of its inertia and the spring 59. This movement of the arm 53, as shown in dotted. line, is sufficient, within the limits of the opening 56, to bring the pin 58 against the lever arm 39 and snap the switch contacts to open position.

With the foregoing arrangement, the switch contacts will always be opened irrespective of whether the battery voltage is sufficient to move the armature to fully stressed condition of spring 24 or only a partially stressed condition thereof. Also, it will be noted that the opening of the switch contacts is not dependent upon any specific position of the armature, but merely depends upon the cessation of its movements during the rewinding operation.

From the foregoing description, it will be apparent that the herein described invention provides in a spring-driven clock or timing device an improved rewinding mechanism which embodies an improved control means for the rewinding mechanism; which utilizes a novel mechanical resetting means for actuating the control switch contacts on the rewind mechanism to open position, wherein the resetting operation is mechanically motivated in response to relative movements between the armature and an inertia member carried by the armature; and which provides a rewinding mechanism which is especially advantageous where insufiicient voltage might be provided to move the armature to a position corresponding to fully stressed condition of the main driving spring.

It is, of course, to be understood that although I have described in detail a single embodiment of my invention, the invention is not to be thus limited but only insofar as defined by the scope and. spirit of the appended claims.

I claim as my invention:

1. In a spring-driven timing device, a rewind mechanism including a magnetically actuated armature for stressing the driving spring, an energizing circuit for said mechanism, a switch hav ing contacts for opening and closing said circuit, a member carried by said armature and supported thereon for relative movements, said member being movable under its inertia, upon cessation of rewinding movement of the armature, to a position for opening said contacts.

2.In a spring-driven timing device, a rewind mechanism including a magnetically actuated armature for stressing the driving spring, an energizing circuit for said mechanism, a switch having contacts for opening and closing said circuit, and a member carried by said armature for actuating said contacts to open position, said member being pre-set in response to the rewinding movement of said armature and released to actuate said contacts upon cessation of movement of said armature.

3. In a spring-driven timing device, an electrically actuated rewind mechanism including a member moved in one direction during rewinding operation for stressing the driving spring, an arm carried by said member, said arm being pivoted for swinging movement and weightedat its free end, an energizing circuit for said mechanism, and contacts for controlling said circuit, said contacts being actuatable to open positions by' the swinging movement of said arm upon the termination of the movement of said member. I

4. In a spring-driven timing device, an electrica'lly actuated rewind mechanism including a member moved in one direction during rewinding operation for stressing the driving spring, an arm pivoted on said member for limited swinging movements and having a weight at its free end, resilient means normally biasing said arm toward one of its limits of movement, said arm be-' ing moved against said resilient means by its inertia, when said member is moved in said one direction, an energizing circuit for said mecha-,

nism, and contacts for controlling said circuit operable by movement of said arm by said spring,

when the movement of said member in said one direction is terminated; 5. Control means for an electric rewind clock mechanism including an energizing coil and a spring biased armature arranged to be attracted during a rewinding operation; said means comprising a switch having contacts for opening'and closing a circuit to said energizing coil, said contacts being actuated to closed position by the movement of the armature during normal operation of the clock, and a weight member carried by thev armature and having limited relative movement to the armature, said member upon cessation of armaturemovement, when attracted by said coil, acting under its inertia 'to actuate the switch contacts to open position and de-enrelative movement thereto, said member being arranged upon cessation of armature movement, when the armature is'attracted, to move under itsinertia and actuate the movable contact out of engagement with the stationary contact.

7. In a spring-driven timing device, an electri- I cally actuated rewind mechanism for stressing the driving spring, a weight member carried by a part of said mechanism movable in response to the rewinding operation and adapted to continue its movement under its own inertia after the rewinding operation has terminated, an energizing circuit for said mechanism, and switch means for controlling said circuit having contacts operable to open position by said continued movement of the weight member.

8. In a spring-driven timing device, a rewin mechanism including a member movable in one direction, when the rewinding mechanism is en ergiz'ed to stress the driving spring, an energy supply source for said mechanism, a weight I member carried by said first member and mount ed thereon for independent limited relative movement under its inertia, and means for disconnecting said source relative to said mechanism in. response to said relative movement of the weight member. T

9. In a spring-driven timing device,'a rewind mechanism including a member movable inone.

direction, when the rewinding mechanism is ensource relative to said mechanism in response to the movement of said weight member in concert with said first member, and in response to the movement of said weight member to its said other limit position in the event that the concerted movement of the members is of insuificient amplitude to actuate said means; 10. In a spring-driven timing device, a re wind mechanism including a member movable in one direction, when the rewinding mechanism, is energized to stress the driving spring, an -en-. ergy supply source for said mechanism, a weight member supported on said first member for limited relative movements in opposite directions to a first limit position and asecond limit position respectively, the inertia of said weight member acting to move it to said first limit position upon beginning the movement of said first member, and to said second'limit position uponcessation of movement of said first member, said members being movable in concert when the weight mem-' ber is in its first limit position, mean normally biasing said weight member for movement toward its second limit position, -and means for disconnecting said source relative to said mech= anism in response to the movement of said weight member in concert with 'said'first member, and in response to the movement of said weight member to said second limit position in the event that the concertedmo-vement of the members is of insufficient amplitude to actuate said latter means. j

11. A timing devicecomprising a driven member, a driving mechanism including a driving spring, means connecting said driving mecha nism to said driven member to drive the same, said driving mechanism being actuated bysaid spring for movement in one direction to drive said driven member, electrically operated re,- winding means for intermittently moving said drlving mechanism in the opposite direction to load saidspring, an energizing circuit-connect to said electrically operated rewinding means; a switch in said energizing-circuit, means for closing said switch responsive to a predetermined unloaded condition of said spring, and inertia controlled means for opening said switch carried by said driving mechanism and'mounted thereon 'for relative movement with respect thereto, said inertia controlled means being operative upon cessation of movement of said driving mechanism in a rewinding direction at any point in its path of travel.

JOHN W. HOBBS.

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