US2531966A - Electromagnetic timepiece with oil shield - Google Patents

Description

INVENTOR.

RTTORNEY J. BERGE ELECTROMAGNETIC TIMEPIECE WITH OIL SHIELD Filed Dec. 11, 1944 Nov. 28, 1950 Patented Nov. 28, 1950 ELECTROMAGNETIC TIMEPIECE WITH OIL SHIELD Joseph Berge, Maplewood, N. J assignor to J aeger Watch Company, Inc., New York, N. Y., a corporation of New York Application December 11, 1944, Serial No. 567,688

l 3 Claims.

This invention relates to timing mechanisms, and more particularly to that type of mechanism designed for embodiment in time clocks, or for association with other instruments to control the operation of the latter at a predetermined time.

In a known type of timing mechanism the operation of the latter is effected by electro-magnetic energy. For this purpose, there is employed a balance wheel which constitutes an armature, said balance wheel or armature being connected with one side of a suitable source of current, such as a storage batter and having a contact pin adapted to engage a resilient contact finger that is connected with the opposite side of said battery or current source. Engagement of the contact pin with the contact finger, which occurs upon rotation of the armature in opposite directions effected by the usual hair spring, completes the electric circuit to a coil or solenoid which is then energized and creates an electromagnetic force in two oppositely disposed pole pieces, whereupon the armature or balance wheel is magnetically given an impulse in each direction, thereby sustaining the oscillations of said armature indefinitely so long as .current is supplied to the timing mechanism.

The oscillations of the balance wheel are transmitted to a cam type escapement member which is carried by the balance wheel staff adjacent the contact pin and contact finger, and acts to intermittently rotate a cooperating escapement wheel in one direction only, thereby controlling the rate of movement of the usual reduction gears to effect operation of time indicating means, or to effect operation of an associated device at a predetermined time.

In order to reduce frictional drag of the cooperating escapement wheel and member on the balance wheel and thus insure accurate operation of the timing mechanism, it is the usual practice to lubricate said escapement member and wheel, as well as other parts of the mechanism, which is applied by the manufacturer upon assembling of said mechanism. The lubricant used is of a low viscosity to prevent congealing at low temperatures and drag on the timing mechanism, thereby insuring accurate operation of the timing mechanism at all temperatures.

Usually, after a short period of operation of the timing mechanism, the lubricant on the escapement wheel and member creeps along the latter and along the balance wheel staff onto the contact pin and contact finger. This objectionable result is aggravated when the timing mechanism is used in an inclined position, or when it is used with the balance wheel staiT disposed vertically and Such that the contact pin and contact finger are located beneath the escapement member. Under these conditions the lubricant on the contact pin and contact finger mixes with the scale or oxide produced by the fine spark created thro h breaking of the contacts and burning into the contact surfaces, and a paste or grease is thereby formed which acts as .an insulator and prevents flow of electric current through the contacts to energize the coil, rendering the timing mechanism inoperative. It i then necessary to disassemble the timing mechanism and thoroughly clean the contacts before said mechanism can be of further use for its intended purp It is accordingly one object of the present invention to provide a timing mechanism of the magnetically operated type having novel means for preventing lubricant used in said mechanism from affecting the accurate and efficient operation thereof, thus eliminating the difiiculty above referred to.

Another object of the invention is to provide a novel lubricant intercepting and absorbing member for an electromagnetic timing mechanism whereby the balance Wheel controlled contacts are maintained free from lubricant for effective operation of said mechanism.

A further object is to provide a novel metallic lubricant intercepting and absorbing member disposed between the escapement means and the contacts of an electro-magnetic timing mechanism, whereby lubricant used on said escapement means is prevented from "fou1ing said contacts and rendering said mechanism inoperative,

A still further object is to provide a novel lubricant intercepting and absorbing member which may be incorporated in existing electro-magnetic timing mechanisms to prevent lubricant in said mechanism from fouling the electrical contact means and rendering said mechanism inoperative.

The above and further objects and novel features of the present invention will more fully appear from the following detail description when the same is read in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are for the purpose of illustration only, and are not intended as a definition of the limits of the invention, reference for this latter purpose being had primar-11y to the appended claims.

in the drawings. wherein like reference char ternally threaded to receive a nut 59.

per end a nut from plate o acters refer to like parts throughout the several VIEWS,

Fig. 1 is a horizontal section of an electro-magnetic timing mechanism constructed in accordance with the present invention, said section being taken on the line Il of Fig. 2;

Fig. 2 is a side elevation of the mechanism shown in Fig. l; and

Fig. 3 is an enlarged detail View of the balance wheel assembly shown in Figs. 1 and 2.

Referring to the drawings, the present invention is illustrated in connection with a timing mechanism of the clock type particularly adapted for installation in automobiles. As shown, said clock and timing mechanism comprise a balance wheel staff 5 journalled at its opposite ends in jeweled bearings (not shown) suitably. mounted in plates 6 and i. The latter are secured together in superposed spaced relation by two pillars 8, each having one end secured to plate is, and the opposite end extending through plate 6 and ex- Stafi 5 has fixed thereto adjacent plate l a hair spring H], one end of which is anchored in a stud ll three circumferentially spaced arcuate pallets l3. Arranged adjacent the path of movement of pallets l3 are two oppositely disposed pole pieces l4 and i5 having wound thereon a coil or solenoid H5. Pole pieces id and it are en- P gaged over pillars S and fixedly held thereon in proper position relative to armature H: by spacers l1 surrounding said pillars between said pole pieces and plate l.

Secured to armature l2 and extending downwardly therefrom is a contact pin 58 adapted to make contact with the free end of a resilient contact finger l9 secured to a post as which, in turn, is secured to an arm 29. The latter is insulated from plate 5 and held thereon by a screw 22 that extends upwardly through said plate and arm 2!, and has threaded on its up- Screw 22 is also insulated and from a resistor 2d surrounding said screw between nut 23 and arm 2i.

between arm 2| and resistor 2 and a second conductor 26 leading from said coil is connected between said resistor and nut 23. Screw 22 is connected by a conductor 2'! to one side of a source of electric power 28, the opposite side of said source being connected by a conductor 29 to a threaded post 39 secured in plate 6. In commercial use, post as serves as the means for mounting the clock mechanism on the instrument panel of the automobile, and since said panel is grounded, the latter serves as the conductor 29 for connecting the mechanism with one side of the power source or storage battery 28. The magnetic circuit for the actuating solenoid l6 and pole pieces l4, l5 may thus be traced from one side of battery 28 through conductor or panel 29, post 30, plate 6, pillars 8, plate 1, stud ll, hair spring ll], stafi 5, armature l2, contact pin !8, contact spring l9, post 20, arm 2|, conductor 25, coil l6, conductor 26, nut 23, screw 25, and conductor 2'! to the opposite side of battery 28. The resistor 24 being located between the conductors 25 and 26 for coil [6 pro- A conductor 25 leading from coil I6 is connected tects the contacts [8, [9 against burning during long use.

When no current is supplied to solenoid [6, the armature i2 is disposed with its pallets l3 in the position shown in Fig. 1, and the contact pin is is engaged with contact finger [9. As- Sumii'lg now that battery 28 is connected with screw 22 and post 36, oscillation of armature i2 is initially started by conducting the current for an instant around the contacts l8, 19 directly from plate 1 to post 20 by means of a manually operated conductor (not shown) provided for this purpose. In this manner coil It is subjected to the maximum energy of battery 28, and said coil and pole pieces l4, l5 are energized and magnetically whip the armature 12 in a clockwise direction, as viewed in Fig. 1, thereby contracting and energizing hair spring H3, and breaking the circuit at l8, I9. Armature i2 is now rotated counter-clockwise (Fig. 1) by hair spring Hi, and the circuit is again closed for an instant by contacts 58, [9, again energizing coil l6 and pole pieces :4, l5, whereupon armature i2 is magnetically given an impulse in the counter-clockwise direction, thereby expanding and energizin hair spring l0. When the circuit is again broken by relative movement of the contacts, spring l8 rotates said armature in a clockwise direction and the cycle is repeated as long as current is supplied to screw 22 and post 36, thereby sustaining the oscillations of armature or balance wheels 52 and stall 5.

The oscillations of armature l2 are transmitted to an escapement member 3| (Fig. 3) secured to stafi 5 beneath said armature and the contacts l8 and i9 and provided with two 0ppositely inclined cams 32 and 33 that alternately engage successive teeth on an escapement wheel 3 (Fig. 2) to impart intermittent movement to said wheel in one direction only. The operation of earns 32 and 33 is such that upon clockwise rotation of armature l2, cam 32 will engage a tooth on wheel 35 and move the latter, and upon counter-clockwise rotation of said armature, cam 33 will engage the same tooth and further move said wheel, thereby moving wheel Be one tooth for each complete oscillation of armature l2.

Escapement wheel 34 is associated with and drives a worm 35, said wheel and worm being suitably journalled on plate 6. Worm 35 meshes with a worm gear 36 secured to a shaft 31 journalled in suitable bearings in plates 6 and l. Worm gear 35 drives a reduction gear train 38 including gears 39 and 4B, for operating time indicating hands ll and 42 relatively and accurately, said hands cooperating with a, dial 43 carried by plate 6.

Novel means are provided for preventing the lubricant that must be applied to cams 32 and 33 and to the teeth of escapement wheel 34 to reduce frictional drag on armature [2, from creepin along escapement member 3! and fouling the contacts 58 and I9, said means serving to intercept and absorb the creeping lubricant before it can reach the contacts I8 and i9. As shown, said lubricant intercepting and absorbing means or thwarter comprises a truncated cone-shaped disc 44 of a diameter larger than the diameter of escapement member 3! and surrounding the balance wheel or armature staff 5 between said escapement member and the contacts l8 and I9. Thwarter 44 is secured to stafi 5 for oscillation therewith by a push fit, and while it may be made of any suitable absorbing material, it is preferably of a porous metallic substance formed by compressing under comparatively heavy pressure a mixture of powdered or granulated metallic ingredients, such as copper and tin, the copper predominating, into a relatively hard and compact mass, and thereafter heat treating said mass to form an alloy or bronze of a porous character. After heat treating, the porous metallic substance is sized to the desired diameter and bored out to provide a central opening for reception of the staff 5. The porous metallic lubricant interceptor and absorber may also be made from a mixture of copper, tin and lead, or copper, tin and zinc, the copper in each case predominating. Thwarter 44, due to its location and absorbing qualities, will thus not only intercept any lubricant creeping from the escapement means 3|, 34 before it can reach the contacts l8 and I9, but will also absorb said lubricant, thereby further insuring that said contacts will be maintained dry and free of lubricant for accurate and continued operation of the timing mechanism. In the illusstrated embodiment of the invention, the diameter of the thwarter is substantially one and one-half times the diameter of escapement member 31, and the thickness is substantially equal to two-thirds the distance between said member and contact pin l8, the shape of the thwarter providing clearance for rotation of escapement wheel 34.

There is thus provided a timing mechanism of the electro-magnetic type wherein accurate and continued operation of the same is assured through the provision of novel means for preventing lubricant used in said mechanism from getting on and fouling the circuit making and breaking contacts thereof, said means preferably comprising a member made of a porous metallic substance and surrounding the balance wheel stafi between the escapement means and the contacts, and acting to intercept and absorb any lubricant creeping from said escapement means before it can reach said contacts. The lubricant intercepting and absorbing member participates in the oscillation of the balance wheel stafi and, accordingly, it is not subject to any wear and will last indefinitely. Further, because of the metallic construction of the lubricant intercepting and absorbing member, the timing mechanism is not subjected to any loose particles which will tend to clog or jam said mechanism. Additionally, the lubricant intercepting and absorbing member constitutes a new article of manufacture which can be incorporated in existing electro-magnetic timing mechanisms to prevent lubricant in said mechanism from fouling the contact members.

Although a single embodiment of the invention has been illustrated and described in the foregoing specification, it is to be expressly understood that changes may be made therein without departing from the spirit and scope of the invention, as will now be clear to those skilled in the art. For example, a member made of felt, leather or any other absorbing material may be substituted for the porous metallic member 44. Likewise, a disc having a depending skirt partially surrounding the escapement member 3| may also be used. Also, the size and shape of the thwarter 44 may be varied from that hereinbefore given to suit various embodiments of said thwarter. For a definition of the limits of the invention, reference is had primarily to the appended claims.

What is claimed is:

1. In a timing mechanism of the type having a staff, a balance wheel on said staff, electromagnetic means for imparting magnetic energy to said wheel, means including a contact pin on said wheel for periodically connecting a source of electric current with said electro-magnetic means, and a lubricated escapement member carried by said staff adjacent said contact pin, the combination therewith of a porous metallic member normally free of any lubricant and oscillatable with said staff and disposed between said contact pin and said member.

2. In apparatus of the character described having a stafi, a balance wheel on said staff, electro-magnetic means for imparting magnetic energy to said Wheel, and circuit closing means under the control of said wheel for periodically connecting a source of electric current with said electro-magnetic means, the combination therewith of a porous metallic thwarter normally free of any lubricant and secured to the shaft for intercepting and absorbing lubricating oil creeping along said shaft toward said circuit closing means.

3. A timepiece having a staff, a spring biasing the stafi in one angular direction, electromagnetic means biasing the staff in the other direction, and an electric contact member carried by the staff and operating to intermittently close and open the electro-magnetic circuit, a lubricated escapement on the stafi, and a finely porous metallic wall on the staff between the lubricated escapement and the contact.

JOSEPH BERGE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 973,114 Haudenschild Oct. 18, 1910 1,546,075 Horn July 14, 1925 1,826,719 Battegay Oct. 13, 1931 2,182,414 Tarbell Dec. 5, 1939 2,233,921 Junghans Mar. 3, 1941 OTHER REFERENCES Ser. No. 437,434, Quebatte et al. (A. P. (1.). published July 13, 1943.

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