US2507974A - Crown for combined winding and setting stems of timepieces - Google Patents

Description

May 16, 1950 G. HENRY CROWN FOR COMBINED WINDING AND SETTING STEMS OF TIMEPIECES Filed Feb. 28. 1946 lfl VE-Nnie GEOQGES Han e) Patented May 16, r 1950 CROWN FOR COMBINED WINDING AND SETTING STEMS OF TIMEPIECES Georges Henry, Geneva, Switzerland Application February 28, 1946, Serial No. 650,784

In Switzerland April 25, 1945 4 Claims.

'There exist numerous classes of spring actuated time pieces, serving either for time indicating, time recording or for automatically controlling functions which are to take place at predetermined times.

Most of said time pieces comprise a housing or case, and a mechanism often called the movement housed in said case. This movement includes a main spring actuating time indicating means (hands or figure carrying members or other moving indexes or other actuated organs for controlling said function), motion transmitting means between said main spring and said indicating means, a stem connecting at will either with said main spring or said indicating means within said case and reaching through the wall of said case to the exterior. This stem enables both the winding of said main spring and the setting of said time indicating means to be performed from the outside of said case, and a crown at the end of said stem serves for the manual control of said stem, the outer boundary surface called later the peripheral surface of said crown giving the proper grip for said manual control. Of all classes of spring actuated time pieces, the most important one by its large number of pieces in use is certainly the watch. For this practical reason most of the present description refers to the watch but this should not be taken as a limitation in the application of the present invention.

In most watches known, it is possible to mount the combined winding and setting stem only after the movement has been placed in the case. The stem, already equipped with its crown, is then introduced from the outside through an opening of the case, usually provided with a tube there, and held in place by the action of a screw located on the movement in the case.

This feature did not show serious inconveniences with the older types of watches although it was necessary to open the case and expose the movement to dust for themere replacement of a defective or worn-out crown for instance; but with the modern types of so called waterproof watches, the question is quite different.

The watch manufacturer was compelled to take great pains in the design and execution of the bottom of the case in order to insure watertightness of the joint with the case and at the same time find a mechanical connection between these two elements which would discourage the amateur from removing the bottom of his watch for the sake of curiosity. Indeed, when this happens to a watch, its waterproof qualities are almost certainly lost. This is one reason for the peculiar polygonal or notched bottoms known and requiring a very special key for the opening and tightening of the waterproof bottoms.

Considering on the other hand the commercial importance of external appearance of the watch case and in view of the continuously varying taste of the buyer, it would be very advantageous for the merchant or even for the manufacturer to be able to take a complete movement, all ready, tested, regulated and mounted in its watertight case, and dress it with an outer shell at the choice of the customer,

From the above, the serious advantages may be appreciated which would be afforded by the use of a crown mountable from the outside and which would not necessitate the opening of the case for this work.

Various solutions of this problem are known. Some, consisting in a sort of elastic chuck connecting a one-piece crown with the stem, present difliculties for the water-proof watch owing to the clearance required for the proper operation of this chuck and the resulting unsecure functioning or loosening of the crown.

Others consist in a crown held from the outside by means of a screw or a blind nut tightened axialy on the stem; unfortunately, all forms known of this type have the great disadvantage of modifying the external appearance of the crown and, which is worse, of leaving the unmistakable indices of the manner in which the crown is fastened (slot, holes or notches). serious danger for the waterproof watch in which a watertight packing is usually provided between stem and case. Indeed when such a crown has been taken apart and reassembled once by the amateur, chances are that it will never be tigh again.

The invention has for its object a crown of usual external shape for a winding and setting stem to be used in connection with any time piece whose movement is enclosed in a case. It may be mounted from the exterior without necessitating the opening of said case and is free from the inconveniences set forth above. This crown is made of two distinct parts, coaxially superposable, one of these parts being provided with organs for its coupling in rotation with the stem, while This is a contribute in a substantially equal manner to the formation of the total peripherical surface of the crown so constituted. Once assembled, said crown shows no evident trace of the manner in which it is held in place.

Another character of the invention is to allow for the use of a watertight packing or seal of usual design between the case and the crownpart which is closest to the case, as well as for an intermediate packing between both crownparts.

Further, with watches which are not of the waterproof type, the packing may be either left out entirely or replaced by an elastic member.

The elasticity of said packing or said elastic member, added to the own elasticity of one at least of the two crown-parts facilitates during assembling the small flutes directed substantially parallelly with the axis of said stem and with which both parts may be provided, to be brOught to lineup exactly.

The accompanying drawing shows by way of examples two forms of embodiment of the invention.

Fig. 1 is a perspective view of an assembled crown;

Fig. 2 is an axial section of a first form of embodiment;

Fig. 3 is an axial section of a second form of embodiment.

With reference to the drawing, a case i is provided with a tube 2 tranversed by a combined winding and setting stem 3 equipped with a portionwith square cross-section t and a threaded portion 5. A crown 6 has its peripherical portion divided across the hight by a plane perpendicular tothe axis of the stem in two substantially equal parts or halves 6a and b contributing in substantially'equal manner to the formation of the peripherical surface 60 of the resulting crown.

The difference in diameter between tube 2 and the-portion of the stem entering said tube is sufficient to-allow for the easy introduction of the stem'into the tube when placing the whole mechanism equipped with the stem into the case. The portion 61) of the crown terminates in a cylindrical sleeve 1 whose outer diameter leaves the clearance usually given between an ordinary stem andthe case tube. The end of said sleeve is providedwith a square hole to match with the portion 4'with square cross-section of the stem thus obtaining a coupling in rotation between stem and'crown part 6b, closest to the case. It is quite obvious that this arrangement, although most common in watches, may be replaced by any equivalentzmeans coupling said two parts in rotation. Crown-half 6b is equipped with a so called watertight packing or seal of known design 8. Crown-half 6a terminates in a cylindrical portion provided with a threaded hole for screwing said halfon said threaded end 5 of said stem. Between both crown-halves 6a and 6b, a recess is provided for the housing of an intermediate watertight packing ID for efficiently sealing the clearance space left between said two crownhalves. When the new type of crown is to be used for an ordinary watch, i. e. not of the watertight type, this intermediate seal may be simply left out or replaced by an elastic element, a spring washer for instance as indicated by I9a in Fig. 3.

As already referred to previously, the complete movement, equipped with its winding and setting stem, is placed as a whole in the case.

The movement is held inclined with respect tothe case and the stem end introduced in the inner tube opening. By gradually establishing parallelism between movement and case the stem may be fully engaged in the case tube and the movement reaches its final position in the case where it may be fastened in any usual manner.

Crown-half 6b is slipped over the stem and in case tube 2, engaged over said stem square 4 and held in a clamping tool which thus maintains the stem against rotation. Crown-half 6a is then screwed tightly on the stem by means of a wrench. In the case where the crown-halves are provided with the usual knurling made of small grooves or flutes substantially parallel to the axis of the stem, the surface of the flutes serve for a better grip of both said clamping tool and wrench whose shape should then be made to match said flutes.

The upper crown-half is hollowed-out and a relatively thin and flexible membrane thus formed affords sufficient elasticity to allow for the exact lining up of said flutes provided in both crown-halves when tightening upper crown-half 6a. Lower crown-half So being also hollowedout to a certain extent gives additional elasticity as well as the intermediate packing itself or in the ordinary watch the elastic member already mentioned.

Owing to the fact that both crown-parts contribute in a substantially equal manner to the formation of the total peripherical surface of the finished crown, it is possible to give the latter the usual shape and appearance, the division in two halves leaving but an almost invisible line across the knurled or fluted portion and giving at any rate no evident indication as to how the crown is fastened on the stem.

The combination described seems to be the most obvious one, but it is evident that both crown-halves may be inverted in their relative functions. Instead of a drilled-out part with a square hole and a part with a blind threaded hole, the combination of a drilled-out part and a part with a blind square hole may be used.

Fig. 53 shows a slightly different form of embodiment of the invention allowin each crownhalf to perform individually and independently from the other the mechanical functions of a usual one-piece crown. In this design, the extremity lb of sleeve 1 of crown-half 6b is thinned out and provided with a slight internal bead 'lc engaging with a corresponding groove lb provided on the square of the stem. The elastic chuck thus formed permits of a checking of the proper functioning of the winding and setting steam without requiring the other crownhalf tobe fastened on the stem. The fact that such an elastic connection may be disengaged easily by a simple pull on the crown-half is no objection here as is the case with known designs of similar type used with one-piece crowns known and mentioned in the introductory part of the present description because for ordinary use, the lower crown-half is firmly held in place by the upper crown-half.

It may be seen readily that when leaving out the lower crown-half, the upper-half may be screwed tightly on the stern until the end face of its cylindrical central portion comes to rest against the square shoulder of the stem and may thus allow for the checking of the proper functionin of the stem as is the case with the lower crown-half alone.

It is quite obvious that without departing from the spirit and scope of the present invention, a split crown such as described may be used for controlling from the exterior the winding and setting stem of any time mechanism enclosed in a case, with particular reference to devices which shall be protected by watertight or fiuidtight cases or more generally stated in tight housings.

I claim:

1. In a time piece, the combination, comprising, a case, a stem mounted in said case for axial displacement and rotation, said stem including a part extending from one end and having a threaded and a polygonal portion, a first crown part including threaded means coacting with said threaded stem part, a second crown part mating with said polygonal stem part for rotation therewith, flutes formed on the peripheral surfaces of both crown parts, a recess formed in one of said crown parts and opening toward the other part, and elastic sealing means in said recess for holding said crown parts in a predetermined position of alignment of the flutes in both crown parts.

2. The combination according to claim 1 and also comprising another recess in one of the crown parts nearest said case, and sealing means housed in said other recess.

3. In a time piece, the combination, comprising a case, a stem mounted in said case for axial displacement and rotation, said stem including a part extending from one end and having a threaded part and a polygonal part, a first crown part including threaded means coacting with said threaded steam part, flutes formed on the peripheral surfaces of both crown parts, a second crown part mating with said polygonal stem part for rotation therewith, a recess in one of said crown parts partly occupied by the other of said crown parts, and elastic sealing means in said recess for holding said crown parts in a predetermined position of alignment of the flutes in both crown parts.

4. The combination according to claim 3 and also comprising another recess in the other of said crown parts and extending into said first recess, and sealing means in said other recess.

GEORGES HENRY.

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

UNITED STATES PATENTS Number Name Date 2,270,384 Simon Jan. 20, 1942 FOREIGN PATENTS Number Country Date 2,203 Great Britain Jan. 26, 1884 79,360 Switzerland Apr. 1, 1919 182,768 Switzerland June 2, 1936 208,581 Switzerland May 16, 1940

Images