Watch crown

April 9, 1968

R. J. GROHOSKI ET AL

3,376,701

WATCH CROWN

Filed July i, 1966

Sheets-Sheet 1.

<img file="US3376701A_D0001.tif" />

<img file="US3376701A_D0002.tif" />

April 9, 1968

Filed July 1, 1966

R. J. GROHOSKI ETAL

WATCH CROWN

3,376,701

Sheets-Sheet 2

<img file="US3376701A_D0003.tif" />

<img file="US3376701A_D0004.tif" />

April 9, 1968 r. j, grohoski etal 3,376,701

WATCH CROWN

Filed July 1, 1966 , =, . . ,

Sneets-Sheet

<img file="US3376701A_D0005.tif" />

United States Patent Office

3,376,701

Patented Apr. 9, 1968

It has been found that previous crowns permitted leakage because their gaskets were unsealed or unseated by side-wise pressures on the crown. Such pressures are prevented from affecting the sealing of the crown of the present invention because of its self-lubricating ring.

Other objectives will be apparent from the detailed description of the preferred embodiment given below, taken in conjunction with the accompanying drawings, in which:

. i V^{S a Slde vertical} sectional view of an embodiment of the present invention; and ^FI.^GSL ?~^{9 are side secti}°nal views of other embodiments of the present invention.

. The waterproof crown construction shown in FIG. 1 ra^cIudes a crown body 1. The crown body, preferably constructed of brass, or stainless steel, has teeth 2 to enable the Ungers to grip the crown for turning. The crown is turned when, the watch is set in either a mechanical or e ectric watcn and when the latch is wound in a mechanical watch. The crown body has a tubular cavity 3 forming a pedestal (center body) 4. The pedestal 4 has internal screw threads 5 which are screwed onto the external screw threads 6 of the winding stem 7. The winding stem is connected to gears which in a mechanical watch in one position, usually toward the case body, winds the mainspring In its other position, usually pulled out rrom the case body, the crown sets the hands. In an elecbodv^Wtnit Λ⁶ ΓΤ ^{USUally is pulled out from} the case body to set the hands.

neId_ant^CS^ViTh³ °^f T’ ^b°^{dy 1 fits over the case}₃₀ pendant 8. The case pendant 8 is a tubular neck which is bezef 30^WTh ^{&amp; the Watch case}&gt; ^usuallV ‘he bezel 30. The cavity 3 has an enlarged lower portion 9 ittlli7Pd^Sf^{adapted f}°^{r the lnsertion of} the crown members utilized to prevent entry of water from outside of the ³⁵ fh^{d throu8h the crown} body and the internal openng of the case pendant and into the watch. A hard selfhe ton of ¹⁰’ ^{preferabIy of} Fustic, is positioned at the top of cavity portion 9. The plastic ring may be relat^meX«y molded ^with great accuracy by conven⁴⁰ 1 r ¹ “^]ect?^on molding techniques. The plastic is a selfmer^{n preferably an a}«tal copolymer. Suitable aceial copolymers include “Celcon” brand manufactured by Celanese Corporation, or “Delrin” brand’ manufactured by Du Pont. Other suitable plastics “re formed by the mixture of “Teflon,” Du Ponfs brand of no ^y^^LrafluoroethyJ^ene, with polycarbonates or acetal coUndM ·⁸\Ι^{η addlt}!^on’ moiybdenum-disulfide may be included in the plastic mixture to increase lubricity and reduce wear. The plastic ring has considerable compressive u iinripi’ ci.!.. , . of the crown body

Tn nHHV ^d ?^{1Se thrusts&gt; Such as is sh}&lt;&gt;wn by arrow A In addition, it prevents side-wise motion of the crown S VT ^th0S-^{e th}-^{rusts having side}-wise components similar to the motion in the direction of arrow A }^{S positioned} beneath the plastic ring 10 and.within the lower portion 9 of cavity 3. This gasket 11, in the embodiment of FIG. 1, is originally an O ring ,,^{blCb IS circ}“^{lar ln} .^c™^{ss sec}tion prior to the insertion of ? ΡγΧ.^Ρμ^Π&lt;1λ ^^{Λ1η the CaVity 3 of the cr}°wn body 60 E ? ^eferably, the O ring is made of rubber. The rubber preferably is of the type which is resistant to salt water and may be artificial rubber. The O ring is sufficiently large so that it is compressed and distorted when the crown is positioned over the case pendant. The O ring 65 ^prevents water from seeping between the crown body and the case pendant.

A metal retaining washer 12 is staked or glued within a ledge portion 13 of the crown body 1. The metal re turning washer is used to retain the O ring gasket 11 and 70 1, ^plast.^{lc r}!^{ng 10} within the crown body. It is not possible to simply extend the metal retaining washer 13 as far as the case pendant and to utilize that washer to pre3,376,701

WATCH CROWN

Raymond J. Grohoski and Robert W. Denley, Watertown, Conn., assignors to the United States Time Cornoration, Waterbury, Conn., a corporation of Connecticut

Filed July 1,1966, Ser. No. 562,294

Claims. (CI. 58—90)

ABSTRACT OF THE DISCLOSURE

A crown for a watch is adapted to fit over a tubular pendant. The crown prevents leakage of water into the watch. The crown construction includes elastic annular gasket and a hard annular self-lubricating ring, both of which fit around the pendant.

The present invention relates to watches and more particularly to a waterproof watch crown.

The increased attention that the waters of the world are. now receiving, for leisure activities and economic exploitation, has created a demand for a truly waterproof watch. The life of a deep sea diver may depend upon the accuracy and functioning of his watch, which he uses to time the duration of his dive.

Extensive testing, in the laboratory as well as in practical use, has shown that the present so-called “deep'sea” watches often fail to exclude water from the watch works. This failure is not due to the watch case, but to its crown, even when the crown is of the specially constructed “deep sea” type.

The cause of these failures was difficult to ascertain. Watches were tested under pressures equivalent to water pressure at six hundred feet and the watches worked. Surprisingly, the same watches leaked when they were tested by swimming around in a shallow pool at a depth of three or four feet. The watches could then be emptied of water and re-tested at a pressure equivalent to six hundred feet and again not leak. In contrast, other watches would leak in use at great depths and not leak in shallow water.

The requirement of water-tightness is essential to a crown for a waterproof watch intended for use underwater. However, the crown must also meet the general requirements for a quality watch crown, namely that it does not wear out the tubular neck (case pendant) when it turns; that it is relatively easy to turn; that the crown itself is not readily worn out by its turning on its pendant; and that the crown may be readily replaceable on its stem without requiring the use of special tools. In addition preferably the crown should be relatively inexpensive. Its materials should not be costly and it should be simple to manufacture, in that it is adapted for high-speed production with high accuracy of its parts.

It is the objective of the present invention to provide a waterproof crown construction which prevents entry of water into a watch when the watch is worn under shallow or deep water, which is relatively inexpensive, and which is easily replaceable on its stem.

In. accordance with the present invention, a crown is provided having an internal cavity which fits over its case pendant (the tubular neck portion of the case). An elastic gasket, preferably of rubber, is tightly wedged between the crown and the pendant to provide sealing. The gasket may be, for example, round (an O ring), square or D ' shaped.

A hard self-lubricating ring is provided within the cavity, either above or below the gasket, to prevent sidewise motion of the crown. A metal washer is staked on the bottom of the crown to retain the gasket and the ring ' in their positions.

3,376,701 ring. This interchange is shown in FIG. 9, which is the same as the construction of FIG. 1 except that the position of the ring and the gasket are interchanged and a staking lip 23 is used in place of washer 12.