US2690645A

US2690645A - Watch crown

Info

Publication number: US2690645A
Application number: US205541A
Authority: US
Inventors: Rueger Herman
Original assignee: Hamilton Watch Co
Current assignee: Hamilton Watch Co
Priority date: 1951-01-11
Filing date: 1951-01-11
Publication date: 1954-10-05
Anticipated expiration: 1971-10-05

Description

Oct. 5, 1954 H. RUEGER 2,690,645

WATCH CROWN Filed Jan. 11, 1951 2 Sheets-Sheet 1 FIG. l

FIG. l2

INVENTOR HERMAN RUEGER ATTORNEY H. RUEGER WATCH cRowN Cct. 5, 1954 2 sheets-sheet 2 Filed Jan. 1l, 1951 FIG.6

FIG.8

FIG. l0

INVENTOR HERMAN RUEGER ATTORNEY Y DD Patented ct. 5, 1954 UNITED STATES PAT NT OFFICE WATCH CROWN Herman Rueger, Lancaster Township, Lancaster County, Pa., assignor to Hamilton Watch Company, Lancaster, Pa.

1 Claim.

This invention relates to watch crowns.

Watch crowns must be movable longitudinally as well as rotatably and the necessity of this longitudinal movement makes it necessary to` have clearance between the winding stem which is attached to the crown, and the watch-case. This provides an entrance for dust and moistureinto the watch-case, and to partially seal this opening a slidable sleeve is mounted in the crown, Which sleeve remains stationary with respect to the watch-case and provides a tortuous passage for the entrance of any foreign matter into the watch-case. The object of the present invention is to provide a housing for the sleeve within a watch crown and to provide for retaining said sleeve in working position.

It is a further object of the present invention to provide an improvement in the sleeve and in the means for retaining the sleeve within a well formed in the watch crown to form a more substantial, more dependable working crown and to make it possible to manufacture the crown at a greatly reduced cost.

It is a further object of the present invention to provide a retaining lip for the longitudinally movable sleeve which is integral with the base metal of the crown.

The invention is illustrated in the accompanying drawings in which:

Figure 1 shows a vertical cross section of the crown and die previous to the die stamping operation.

Figure 2 is a similar view showingthe die stamping operation partially completed.

Figure 3 is a similar view showing the die stamping operation completed.

Figure 4 is an enlarged perspective view of the Watch crown looking at the underside.

Figure 5 is a vertical cross section illustrating the attachment of the crown to the winding stem (partially screwed in).

Figure 6 shows a vertical cross section of a modified method of making the watch crown and showing the crown and die at the start of the die stamping operation.

Figure '7 is a similar view to Figure 6 showing the die stamping operation completed.

Figure 8 shows the crown mounted in a chuck with the lip turning roller in operation.

Figure 9 is a half vertical section showing one form of retaining lip.

Figure 10 is a similar View to Figure 9 showing a modied form of retaining lip.

Figure 11 is a detailed view of the improved sleeve construction.

Figure 12 is a greatly enlarged partial horizontal cross section showing the radial outward ow of the metal.

Referring particularly to Figures 1, 2, and 3, a preformed core l5 is provided with an interior annular well I5, said Well having an outer reduced lip portion Il and a central stud I3 by means of which the crown is connected to the winding stern I9 (Figure 5).

An external covering consisting of a brass cap 20 having a thin gold covering 2l is fitted over the core V5 and extends down below the lower edge of the core. Slidably mounted within the well is a sleeve 22 having an upper outwardly turned annular flange 23 the upper end of said flange being formed at an angle more acute than the angle which the bottom of the well makes with the side of the well for reasons which will be hereafter disclosed.

A die having a lower portion 24 and an upper portion 25 and a central opening 26 receives the crown assembly under action of the punch 21. The start of this action is shown in Figure 1. Figure 2 shows the action half way completed, and Figure 3 the completed action. The upper portion 25 of the die is formed with flutes 28 into which the final edge 29 of the crown is forced forming the knurled edge 30 (Figure 4). The core I5 is deformed under this pressure and the cap thickens, as shown in Figure 3 at 3l. Upon engagement of the -cap 2E] with its gold covering 2l with the lower die 2d, as shown in Figure 2, the cap and covering are forced into the position shown in Figure 3, abutting against the lip of the inner well of the core.

This lip upon engaging the lower portion 2d of the die is bent inwardly, as shown in Figure 3 at 32, the edge of the lip stopping short of the sleeve 22, and the lip itself serving to retain the sleeve within the well of the crown while permitting sliding motion of said sleeve.

Heretofore, this sleeve had been retained by a washer held in place by peening the edge of the crown, a diiicult and costly operation. With this construction of crown the sleeve is provided with a retaining means in the same operation as the forming of the contour surface of the crown.

The central stud i8 is centrally bored at 33 but is not provided with threads. The winding stern I9 is formed of hard steel while the core l5 is of soft metal, and it has been found under experiment that by allowing the winding stem I9 to form its own threads in the bore 33, a much better connection is made than if the bore 33 were tapped.

Referring particularly to Figures 6, 7, and 8, diiferent steps are used in the method of producing a watch crown. Figure 6 shows a solid core 34 formed with a central protruding tapered tit 34' to provide centralization of the core in the.

mandrel and having the brass cap 35 and gold covering 36. The lower part of the die 31 is formed to bring the cap 35 with its gold covering 36 around the under surface of the core, as shown in Figure 2, the upper die 38 producing the knurled outer section 30 (Figure 4) in the same manner as the upper section 25 of the dies shown in Figures 1, 2, and 3 operates.

After being formed, as shown in Figure 7, the core is bored to provide a central stud 39 which is bored at 40 and has surrounding it an annular well 4| for the reception of a sleeve 42. In the boring operation the annular well 4I may be formed either with the offset lip, as shown in Figures 8 and 10 at 43, or may be nished with a straight wall as shown in Figure 9 at 44. The crown is then mounted in a chuck 45, as shown in Figure 8, and rotated while rollers 46 (one shown) is brought into contact with the lip 41, which may be either formed as shown at 43 or 44. The roller 45 is directed inwardly, urging the lip into the position, as shown in dotted lines in Figure 8 and in solid lines in Figures 9 and 10. This inturning of the lip may be accomplished by staking or through a Stationary forming tool.

Figure 9, wherein the annular well is formed with a straight side wall as at 44, provides when nished a pleasing rounded appearance as shown at 48, but due to the excess of metal a thickening is provided at 49 which slightly limits the travel of the sleeve 42.

Figure 10 shows the lip 41 formed with a shoulder 50 which serves as a stop during the bending operation by the roller 46. This lip is also provided with a bevel at l so that under the action of the roller, the lip will definitely turn inwardly. Providing the lip with a shoulder and making it slightly thinner determines the point of bend and assures that the sleeve will be afforded more room to travel, although the lip is by reason of its reduced character not quite as strong `as that shown in Figure 9, both methods having a slight advantage of one over the other.

Referring particularly to Figures 9, 10, and 11, the bottom of the well is cut at an oblique angle with the outer side wall, as shown at 52 in Figure 11, while the sleeve has its upper rim formed at a different angle as shown at 53. The cutting of the bottom of the well at an angle is done to assure depth of well and to provide a uniform thickness of the core at the point 54 to resist the strain in the die stamping operation, as shown in Figures l, 2, and 3. The sleeve 42 is formed with an upper ange of a different angle to provide clearances at the corner 55 and to prevent the sleeve from sticking to the bottom surface of the well and thus destroying its usefulness. The sleeve is also beveled at the inner surface of the ange at 56 for a similar reason.

The mandrel 51 common to the dies in each variation is formed with a central bore 58 for the reception of a knockout pin 59. In the variation shown in Figure 1, the knockout pin also serves to support the core concentrically during the forming operation. The punch 21 and the upper die 25 are tapered to provide a tight t and to facilitate the ejection of the crown.

The die is formed of upper and lower separate pieces so that substitution of either may be effected to provide different contour of outside surfaces. The two variations here shown are formed by changing the lower die only.

Referring particularly to Figures 10 and 12, it will be seen that in the crown forming operation the outer gold covering 2l is forced into the flutes 28 to form sharp edges 60, while the brass cap is formed with rounded projections 6l and the inner core is caused to flow out of round as at 62. This flowing of the inner core metal, which is also seen in Figure 10 at 43, materially strengthens the crown. It prevents any possibility of the cap 20 and the outer gold covering 2| turning on the inner core metal which has heretofore been a considerable problem. The sharp edges 60 are a great improvement over the present day crowns, which when seen enlarged to the extent of the enlargement of Figure 12 which is a reproduction of a microphotograph, show rounded and roughened edges.

What is claimed is:

A watch crown comprising an inner base metal core formed of a central stud and an annular well surrounding said stud, said core in its central outer portion being spherically rounded, the inner surface of said annular well being out on an angle substantially parallel to the rounded surface of said core, a cylindrical sleeve slidable on said central stud and within said well, said sleeve being formed at its inner end with an annular ange, the angle of said flange being more acute than said inner wall angle, an inturned lip integral with said core substantially closing the outer opening of said well and engaging the flange of said sleeve to retain said sleeve Within said well.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 355,144 Dalzell Dec. 28, 1886 1,627,471 Wadsworth May 3, 1927 1,904,241 Kammerer Apr. 18, 1933 1,910,078 Wilsdorf May 23, 1933 2,090,251 Cowles Aug. 17, 1937 2,426,289 Wallace et al Aug. 26, 1947 2,511,757 Waldman June 13, 1950 FOREIGN PATENTS Number Country Date 241,453 Switzerland July 16, 1946