US2299519A - Clock - Google Patents

Description

Oct; 20, 1942. WHITEHEAD 2,299,519

CLOCK Filed July 18, 1940 Patented Oct. 20, 1942 CLOCK Richard H. Whitehead, New Haven, Conn., as-

signor to The New Haven Clock Company, New Haven, (John, a corporation of Connecticut Application July 18, 1940, Serial No. 346,070

6 Claims.

This invention relates to instruments of the type having gears pivoted in supporting frames which are here typically represented by and re ferred to as clocks and more particularly to a construction which affords bearings of a superior hardness.

In the construction of watches, clocks, electrical instruments and other instruments involving gears it has been customary to mount the gears in spaced plates, which plates are usually made of brass to secure them from corrosion. These plates must have provided in them the bearings for the pivots of the gears.

Heretofore it has been customary, in the cheaper watches, to journal the gears in holes in the plates so that the pivots themselves have direct bearing against the material of the plate. This material being necessarily soft enough to be subjected to mechanical operations, is liable to wear and at the same time, in spite of all precautions, it has a certain degree of friction which is detrimental to the operation of the instrument.

To overcome these difiiculties it has been customary in the higher grade watches to drill the holes for the bearings large enough to receive a jewel of ruby, sapphire or some synthetic material, which jewel is itself pierced with a polished hole to serve as a bearing for the pivot. This construction produces good results but is quite expensive both because of the cost of the material and the labor of cuttin polishing and inserting them. A watch having such jewels is better time p r and has a longer life than a watch in which the pivots bear directly in the plate as heretofore constructed, but the high cost places this construction beyond the cheaper watch.

It is an object of this invention to provide a watch in which the plates are made 'of an aluminum metal, such as aluminum or a suitable aluminum alloy, having the pivot bearing holes punched, drilled or out directly therein and then to subject the plate to certain hardening processes which convert the aluminum to one of its very hard compounds, for example as shown by Patents No. 2,153,060; 1,946,147; 2,040,617; 2,040,618; 1,891,703; 2,108,603; 2,108,604; and 2,084,327. This treatment is a surface treatment which is capable of giving great hardness to the surface of the material while leaving the inner layers tough. Thus, we have in this invention the ideal combination of a very hard bearing surface at the point where the plate is in contact with the pivot while at numeral .ll designates the back plate.

the same time we have the tough supporting plate clear up to and integral with that bearing surface so that there is no reasonable strain to which the instrument can be subjected which could crack the bearing surface.

The invention accordingly comprises an article of manufacture possessing the features, properties and the relation of elements which will be exemplified in the article hereinafter described and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description, taken in connection with the accompanying drawing, in which:

Fig. 1 is a plan view of a watch movement embodying this invention, illustrating particular.

ly the type of movement used in the ordinary so-called Dollar watch.

Fig. 2 is a side elevation of a watch movement such as is shown in Fig, 1.

Fig. 3 is a view similar to Fig. 1 showing a modified form of the structure.

' Fig. 4 is a further modification.

It will be understood that so far as the arrangement of the gears and pivots or the shape of the plates shown in these views, they form no part of the present invention and any type of instrument or any shape plate convenient to the type of instrument chosen may be employed.

-As illustrated in Fig. 1 the numeral l0 designates the front plate of a watch movement designed to support or underlie the face and the 0 These two being held in spaced relation in any customary manner. As shown, there is provided a main spring I! which, through the means of any convenient gear train, herein illustrated as gears l3 and I4, drives the minute shaft I5 in the customary manner.

Each of the plates l0 and II in the modification shown in Fig. 1 is drilled or punched with suitable holes, here indicated generically with the numeral l6, which holes serve as the pivot holes for certain or all of the pivots of the gears.

As shown in Fig. 1 the back plate carries all of the pivots except the pivot H for the balance wheel l8 and the back pivot IQ for the main spring l2. The balance wheel pivot is carried in a suitable screw l1 and the main spring pivot I9 is carried in an auxiliary plate 20, as shown. Each of these plates l0 and 2.0, in accordance with this invention, is made with an aluminum metal, that is either pure aluminum or an alloy 2 v of aluminum containing a sumciently high percentage of aluminum to be subject to the surface hardening processes which are characteristic of aluminum.

The manufacture of these cheaper watches must necessarily be kept on a quantity production 'of one of the aluminum compounds having a sufficient alloy to render it free cutting and to maintain its stiffness.-

The punching operation is carried with punches of substantially the diameter of the finished bearings, except for the very small train holes which are prick punched and shaved to size. After the plate iscompletely punched and preferably after all mechanical operations upon it are completed, it is subjected to a mechanical surface hardening process which converts the film surface to one of the very hardened aluminous materials. This treatment is conducted in such a manner that the surface conversion occurs particularly throughout the cylindrical surface of the bearing holes but it is desirable that it be conductedin such a manner that only the film surface is treated since a more satisfactory bearing is provided if the hardened surface is immediately surrounded by the tough unhardened metal to resist any tendency to crack or chip.

Ordinarily the process of surface hardening if applied to a surface already polished will produce a polished surfac after hardening. Subsequent further polishing may, however, be performed if desired.

If the particular process of hardening alters the size of the bearing or if the size is to be altered by subsequent polishing, that fact will be taken into account in determining the diameter of the punching dies.

The construction of Fig. i is intended toillustrate a plate made in accordance with this in-' vention in which the whole of the supporting plates III, II and 20 is subjected to the surface hardening process so that .there is a hardening over the fiat surface of the plate as well as at the bearing surfaces. This embodiment of the invention possesses the great advantage that it may be accomplished with a minimum of special at- V tention.

In utilizing this form of the invention, however,

. care must be taken to see that the hardening pen- -etrates down into the bearing surfaces.

fl'he form of the invention shown in Fig. 3 is i fntical with that shown in Fig. 1 except that this figure illustrates a modification in which the surface hardening is confined to the areas im- 'mjediately surrounding the bearing surfaces.

is illustrated by the circles 25, which surround the bearings i8 and I 9. It will be understood that ordinarily there is i no difference in appearance between this metal when surface hardened and the unhardened portion' of the materialso that the placing of this the surface hardening has spread on the surface circle 25 upon theportlon is, to this extent, diagrammatic rather than an illustration of the actualappearance of the finished plate. This circle is intended to indicate the area over which of the plate but it will be understood that in most cases there will be no such hard and sharp lines of division as this circle seems to indicate.

This form of the invention has the merit that it leaves the body of the plate unhardened so that it may be easily subjected to any further operations such as polishing, embossing or engraving to which it may be desired to subject it.

It also possesses the merit when expensive processes are used that the area to be processed is reduced to a minimum.

Where processes are employed which rely pon electrical phenomena, it is possible to secure penetration of the hardening process into the bearing surfaces by providing electrodes capable of passing into these bearing surfaces and where such localization of electrical action is desired, it may. in many instances, be found helpful to provide a local surface hardening at the bearing surfaces rather than to attempt to subject th plate to a surface hardening all over, since the latter is apt to concentrate too much upon the flat surfaces without sufiicient penetration intothe bearings.

Fig. 4 illustrates the invention as applied to the higher grade movement which is ordinarily of the jeweled type. In such case a plurality ofback plates 30 and II are provided, each of which carries on or more of the bearings and each of these plates is hardened at the bearings, either as disclosed in Fig. l or Fig. 3, and for this reason no separable or separate jewels are required.

The pivot I I for the balance stafl may be made in any convenient form, for example the hardened steel screws now customarily used for cheaper watches may be utilized but I prefer to fabricate a part of a screw of aluminum metal having the desired form of bearing surface and then surface harden it as in the case of the supporting plates, so that the balance wheel also may have the benefit of the superior qualities of the surface hardened aluminum. This is particularly important in the case of the higher grade watches where the new construction is to take the place of the balance wheel jewels.

A watch made in accordance with this invention has all the advantages of a jeweled movement in that it has long life, low friction, and accuracy, at the same time it possesses the advantages of a construction heretofore confined to the cheap watch field, namely plate pivots, so that the advantage of hardened bearings may be carried into the cheap watch fleld.

It will also be noted that the watch made in accordance with this invention carries all of the advantages of the high grade jeweled movement without one of the serious limitations to which such movements are subjected, namely with this construction there is no liability of a jewel being cracked, chipped or broken since the hardened bearing surface is immediately surrounded by the more ductile and tougher unhardened material of the plate.

1 Since certain changes may be made in the above construction and different embodiments of the invention could be made without departing from the scope thereof. it is intended that all matter contained in the above description or invention which, as a matter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secure by Letters Patent, is: 1'. An instrument of the type having the pivots of a gear train mounted in bearing supporting plates, having the supporting plates made of an aluminum metal, said aluminum being chemically surface hardened over the surface of the bearing holes in the piece at the bearing surfaces, whereby there is provided a bearing surface comparable or superior to the customary jeweled bearings, said bearing surface being immediately surrounded by the tough unhardened material integral with it.

2. An instrument of the type having the pivots plates, having the supporting plates made of an aluminum metal, said aluminum being chemically surface hardened all over, including the "surface of the bearing holes, whereby there is provided a bearing surface comparable orsuperior to the customary jeweled bearings, said 3. An instrument of the type having the pivots of a gear train mounted in bearing supporting plates, having the supporting plates made of an r of a gear train mounted in bearing supporting gear pivots therein, said bearings being chem-' ically surface hardened over their entire hearing surfaces, whereby there is provided a plate having hardened bearing surfaces integral with and firmly supported by the tough metal of the plate.

5. The process of making a supporting plate for an instrument which comprises forming the plate of an aluminum metal with openings therein suitable for bearings and then chemically surface hardening the plate throughout the bearing areas to leave a thin hardened surface immediately supported by the unhardenedmetal of the plate.

6. An instrument comprising a frame, bearings in said frame, gears pivoted in said bearings, said frame being of aluminum and the surfaces of said bearings being of chemically hardened aluminum integral with said frame.

RICHARD H. WHI'I'EHEAD.

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