US2516720A

US2516720A - Electric clock

Info

Publication number: US2516720A
Application number: US630859A
Authority: US
Inventors: Leland C Parker; Theodore K Riggen
Original assignee: Bendix Aviation Corp
Current assignee: Bendix Aviation Corp
Priority date: 1945-11-26
Filing date: 1945-11-26
Publication date: 1950-07-25
Anticipated expiration: 1967-07-25

Description

July 25, 1950 c. PARKER ETAL 2,515,720

ELECTRIC CLOCK Filed Nov. 26, 1945 S Sheets-Sheet l IN VEN TOR.

WITNESS: W M f yflevdme/l y en fiTORNEY July 25, 1950 c. PARKER EIAL ELECTRIC CLOCK 3 Sheets-Sheet 2 Filed Nov. 26, 1945 July 25, 1950 c. PARKER ETAL ELECTRIC CLOCK 3 Sheets-Sheet 3 Filed Nov. 26, 1945 WITNESS:

Patented July 25, 1950 ELECTRIC CLOCK Leland G. Parker and Theodore K. Riggen, Elmira, N. Y., assignors to Bendix Aviation Corporation, Elmira Heights, N. Y., a corporation of Delaware Application November 26, 1945, Serial No. 630,859

8 Claims.

The present invention relates to electric clocks and more particularly to clocks which are powered by direct current as for instance in automotive installations.

The present invention constitutes an improvement over the structure shown in the application of Riggen Serial Number 630,901, flied November 26, 1945.

It is an object of the present invention to provide a novel electric clock which is eiiicient and reliable in operation while being simple and economical in construction.

It is another object to provide such a device in which the moving parts are balanced with respect to forces of translation so as to minimize the effect of vibration thereon.

It is another object to provide such a device in which the driving and governing functions are all accomplished by the utilization of magnetic iiux.

It is another object to provide such a device in which a single permanent magnet in conjunction with a single electromagnet supplies the flux which is used for all the operating and governing functions.

It is another object to provide such a device which incorporates the magnetic equivalent of a toggle device for controlling the actuation of the energy storing means.

It is another object to provide such a device in which all the functions which have heretofore been accomplished conventionally by the use of springs are now accomplished by means of magnetic flux.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawing, in which:

Fig. l is a side elevation of a clock mechanism constituting a preferred embodiment of the in vention, the casing and certain of the parts being removed or broken away for the sake of clarity;

Fig. 2 is a section taken substantially on the line 22 of Fig. 1 showing the parts in the positions assumed during the power stroke 01' the electromagnet, the electrical circuit for the clock being shown diagrammatically;

Fig. 3 is a similar view showing the position of the parts at the time of energization of the electromagnet;

Fig. 4 is a detail in perspective of a portion of the electromagnet with its controlling armature; and

Fig. 5 is a detail in side elevation of the mounting means for the permanent magnet and the governing disc.

In Fig. 1 of the drawing, there is illustrated a frame comprising an upper mounting plate I, a lower mounting plate 2 and a pair of stirrups or brackets 3 and 4 (Fig. 5) which elements are united by means of a plurality of spacing posts 5, and attaching screws 5 and l.

A clampin member comprising an upper arm 8 and a lower arm 3 is hinged at H to the stirrup 4 and is adjustably attached at its other end to the stirrup 3 by means of a stud i2 threaded in said stirrup. A permanent magnet 13 or U-shape is seated in said clamp and rigidly fixed therein by means of cap screws III which draw together the two arms 01' the clamp.

A pair of arcuate pole pieces II and i! of magnetic material are mounted in the frame spaced a short distance from the end of the magnet l3, and a disc ii of electrically conductive material such as aluminum is mounted centrally in the frame for rotation about a vertical axis in the space between the magnet I 3 and pole pieces H, I! whereby rotation of the disc will be resisted by the flux oi the permanent magnet. This resistance which governs the speed of rotation of the disc is variable by adjustment of the stud I! which varies the space between the magnet l8 and pole pieces ll, 15, and consequently the intensity of the flux traversing the disc I 8.

An electromagnet I1 is rotatably mounted between the pole pieces II, I! of the permanent magnet, the ends of the core I! of the electromagnet being curved to conform to the interior curvature of the pole pieces whereby when the electrcmagnet is deenergized the core tends to align itself between the pole pieces. The coil I! of the electromagnet is connected at one end by a lead 2| to a battery 22 which is grounded at 23, and is connected at its other end by a lead 2| to a contact 25 fixed on the core but insulated therefrom.

An armature member 28 is pivoted at 20 on the core l8 of the electromagnet and carries on its free end a curved bar 21 of magnetic material which partially bridges the space between the pole pieces i4, it. The armature member 28 carries a contact 28 adapted to engage the contact 25 and thereby complete the connection through the coil i9 to the ground as indicated at 2!.

The direction of flow of the current through the coil I9 is such as to cause the electromagnet to be magnetized with polarity similar to the adjacent pole pieces l4, l5 whereby the electrom gn t will be repulsed by the pole pieces and consequently tend to rotate in a. counterclockwise direction as viewed in Fig. 3.

Means for utilizing the return motion of the core I8 01' the electromagnet toward the pole pieces i4 and 15, when the electromagnet is deenergized, to rotate the disc I6 is provided comprising a ratchet wheel 3i mounted coaxially with the electromagnet, and a pawl 32 pivotally mounted on a bracket 33 fixed to the electromagnet in position to engage the ratchet wheel. A magnetic member 34 is mounted on the free end of the pawl 32 in position to be attracted by the pole piece H in order to hold the nose of the pawl in the teeth of the ratchet wheel. Suitable gearing indicated generally by numeral 35 connects the ratchet wheel 3| to the disc it, the ratio of such gearing being so selected as to secure a suitable speed of rotation of the disc to facilitate its governin function.

A portion of the clock face is illustrated at 36 in Fig. 1 and the sweep-second hand 31, the minute hand 38 and the hour hand 39 are shown conventionally as driven by suitable gearing indicated generally by numeral 40, which is also actuated from the ratchet wheel 3i.

It will be observed that the pivoted armature member 26 in conjunction with the pole pieces I 4, l forms the magnetic equivalent of a toggle mechanism. In other words, the armature member will pass back and forth through a dead center position in which the bar 2'! is equally attracted by the pole pieces, and when this .dead center position is passed, the armature will pivot on the core of the electromagnet to open or close the

contacts

25, 26 as the case may be. In order to limit the opening of the contacts and the pivotal motion of the armature member on the electromagnet, an adjustable stop member 4| is provided on the armature member in position to engage the core of the electromagnet.

In operation, starting with the parts in the positions illustrated in Fig. 2, since the

contacts

25, 28 are open, the electromagnet is deenergized and the core I8 is rotated by the attraction of the pole pieces i4, IS in a clockwise direction, which rotation is transmitted through the pawl '32to the ratchet wheel 3| and from thence to the disc I6 through gearing 35, and to the hands of the clock through the clockwork gearing 40. When the rotation of the electromagnet carries the armature member 26 to a position where the bar 21 is closer to the pole piece I5 than the pole piece H, the attraction of the pole piece l5 causes the armature to swing in a clockwise direction on its pivot and bring the contact 28 into engagement with contact 25. The circuit through the coil IQ of the electromagnet is thus closed causing repulsion to take place between the electromagnet and the pole pieces i4, i5 whereby the electromagnet rotates counterclockwise carrying with it the armature member 26. When the armature is carried back through the dead center position, pole piece l4 overcomes the attraction of the pole piece [5, thus causing the armature to pivot on the core of the electromagnet in a counterclockwise direction opening the contacts so as to deenergize the electromagnet and repeat the operation. Stop

members

42, 43 may be provided to cooperate with a projection 44 on the core of the electromagnet to positively limit the arc of its oscillation if deemed desirable.

Although but one embodiment of the invention has been shown and described in detail, it will be understood that other embodiments are possi- 4 ble and various changes may be made in the form and arrangements of the parts without departing from the spirit of the invention as defined in the claims appended hereto.

What is claimed is:

1. In an electric clock a, permanent magnet, an electromagnet pivotally mounted in static equilibrium for movement toward and from the permanent magnet, means for intermittently energizing the electromagnet similarly to the permanent magnet to cause repulsion therebetween, including a magnetic toggle controlling device carried by the electromagnet and actuated by said permanent magnet, a disc of electrically conductive material, means for rotating the disc by movement of the electromagnet to ard the permanent magnet, means causing the flux of the permanent magnet to traverse the disc to govern the rotation thereof, and clock mechanism rotatable with said disc.

2. An electric clock as set forth in claim 1 in which the means for intermittently energizing the electromagnet includes an armature movably mounted on the electromagnet between the poles of said permanent magnet so as to approach said poles alternatively as the electromagnet oscil lates, and contacts opened and closed by movement of the armature on the electromagnet.

3. In an electric clock a permanent magnet, an electromagnet having a core rotatably mounted between the poles of the magnet, and means for intermittently energizing the electromagnet with the same polarity as the permanent magnet including a control armature pivotally mounted on the electromagnet in position to approach one pole of the permanent magnet when the electromagnet is attracted by the permanent magnet, and to approach the other pole of the permanent magnet when the electromagnet is repulsed by the permanent magnet, a contact on said control armature and a contact fixedly mounted on the core of the electromagnet in position to be engaged by the first-mentioned contact when the control armature moves on the electromagnet in the direction of its motion when the electromagnet is deenergized.

4. Clock mechanism as set forth is claim 3 including further a rotatable disc of electrically conductive material, and ratchet mechanism for driving the disc from the electromagnet, the disc being mounted to rotate through the field of said permanent magnet to govern the speed of rotation thereof.

5. Clock mechanism as set forth in claim 3 including further a. rotatable disc of electrically conductive material, ratchet mechanism for driving the disc from the electromagnet, said ratchet mechanism including a ratchet wheel connected to the disc, and a pawl mounted on the electromagnet, and means whereby the flux of said permanent magnet holds the pawl in engagement with the ratchet wheel.

6. In an electric clock a permanent magnet formed with its poles substantially co-planar, a pair of pole pieces forming extensions of said poles but spaced therefrom, an electrically conductive disc mounted to rotate in said space, means to adjust the distance between the magnet and said pole pieces to vary the retarding effect of said disc, an electromagnet rotatably mounted between the pole pieces, means for intermittently energizing the electromagnet to cause oscillation thereof, and means including the electromagnet.

7. An electric clock as set forth in claim 6 in which the means for energizing the electromagnet includes an armature having a pivotal lost motion connection to the electromagnet, and a pair of contacts which are closed by said armature under the influence of one pole piece and opened by the armature under the influence of the other pole piece.

8. An electric clock as set forth in claim 6 in which the ratchet connection includes a ratchet wheel connected to rotate the disc and a pawl mounted on the electromagnet in position to enga e and rotate the ratchet wheel when the electromagnet is rotating toward said pole pieces, said pawl having an armature adjacent one of the pole pieces and adapted to be attracted thereby to hold the pawl in engagement with the ratchet wheel.

LELAND C. PARKER. THEODORE K. RIGGEN.

6 ammcas orran The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 709,818 Harrison Sept. 23, 1902 FOREIGN PATENTS Number Country Date 374,235 France Apr. 12, 1907 491,442 Great Britain Aug. 29, 1938 536,294 France Feb. 9, 1922 606,429 France Mar. 9, 1926