US3271945A

US3271945A - Watch casing with rotatable bezel

Info

Publication number: US3271945A
Application number: US415251A
Authority: US
Inventors: David H Anderson
Original assignee: Bulova Watch Co Inc
Current assignee: Bulova Watch Co Inc
Priority date: 1964-12-02
Filing date: 1964-12-02
Publication date: 1966-09-13
Anticipated expiration: 1983-09-13

Description

United States Patent N' 3,271,945 WATCH CASING WITH RTATABLE BEZEL David H. Anderson, Providence, RH., assignor to lulova Watch Company, Inc., New York, NX., a corporation of New York Filed Dec. 2, 1964i, Ser. No. 415,251 4 Claims. (Cl. 58-43) This application is a continuation-in-part of my copending application Serial No. 272,959 filed April 15, 1963, now abandoned.

This invention relates generally to timepieces adapted to indicate both local time and time in another zone, and more particularly to a watch casing for such timepieces having a rotatable bezel to provide the second time indication.

Watches are known which, in addition to the usual hour, minute and sweep second hands, are provided with a special Greenwich Mean Time hand arranged to revolve around the dial once every 24 hours. This special hand operates in conjunction with a rotatable bezel on the casing calibrated in 24-hour intervals. Such timepieces are primarily intended for airline pilots and marine navigators, for they alford simultaneous displays of local time and Greenwich Mean Time.

Greenwich Mean Time is expressed not in a.m. and p.m. values from 1 to 12, but in 24-hour intervals, midnight being 2400 hours. Thus when local time in New York is 5:30 am., Greenwich Mean Time, which is five hours later, is expressed as 1030 hours, and when local time in New York is 5:30 p.m., Greenwich Mean Time is expressed as 2230 hours.

The modern traveler also has need for a timepiece which indicates both local time and a second time zone, and in some cases, he may require indications in the same time zone in both a.m. and p.m. terms and in hours. For example, international time tables are generally expressed in hourly terms, and a timepiece which gives the time in both forms does away with the need for translation.

While Watches are commercially available having a rotatable bezel to alford the second time indication, such Watches have certain drawbacks. In order to turn the bezel to a new position it is necessary to first depress it, and this not only involves some difiiculty in making the adjustment, but with continued use there is a significant reduction in tension against the bezel and it becomes loose and fails to hold its adjusted position. Moreover, in some instances, the bezel is not effectively locked to the casing, and it becomes disengaged therefrom.

Accordingly, it is the principal object of this invention to provide a watch casing having a rotatable bezel of impoved construction which may be manipulated without depression to alford time readings in a second zone.

Also an object of the invention is to provide a watch casing of the above type which may be used for a prolonged period without significant Wear or change in tension.

Still another object of the invention is to provide a sturdy Watch casing in which the rotatable bezel is effectively locked to the casing.

Yet another object of the invention is to provide a sub-assembly, which includes a holding ring for the watch crystal, a rotatable bezel, as well as spring and friction elements, whereby the sub-assembly facilitates final factory assembly of the watch and ready replacement in the field. A further advantage of the invention is that the rotation friction on the rotatable bezel can be regulated to a fine degree.

Briefly stated, these objects are accomplished by a watch casing in which the dial crystal is maintained with- 3,27L945 Patented Sept. 13, 1966 ice in a holding ring having an outwardly extending annular fiange forming a circular trackway. The crystal is encircled by a rotatable bezel having a downwardly extending sleeve having an inner annular groove which receives the periphery of a split friction washer concentric with the crystal holding ring and engaging the undersurface of said trackway fiange, the washer thereby locking the bezel to the ring, a tension spring being interposed between the upper surface of said trackway flange and the underside of said bezel to apply pressure therebetween and to maintain the adjusted position of the bezel relative to the trackway. The holding ring, the bezel, the washer and the spring together constitute a subassembly unit, which in making the final assembly is pressed down on the dial crystal.

For a better understanding of the invention as well as other features and objects thereof, reference is made to the following detailed description to be read in conjunction with the accompanying drawing, wherein:

FIG. 1 is a plan view of a watch casing in accordance with the invention;

FIG. 2 is a section taken through the casing;

FIG. 3 is a perspective view of the tension ring; and

PIG. 4 is a perspective view of the friction Washer.

Referring now to the drawings, the timepiece in accordance With the invention is constituted by a watch casing provided with a fixed bezel 10 from which extend two sets of lugs 11 and 12 for accommodating spring pins linked to a watch strap in the usual way. The casing is enclosed by a back mem'ber 13 which is held to bezel 10 by a threaded locking ring 14, a gasket 15 being interposed between the back and the fixed ibezel to provide a waterproof closure. The watch-works received within the casing is provided with a standard twelve-numeral dial 16, and includes an hour hand 17, a minute hand 18, and a sweep second hand 19.

In addition to these conventional hands, there is provided a special Greenwich Mean Time (G.M.T.) hand 20 which makes a full revolution per 24 hours. This special hand, which has a triangular tip 20a, moves in synchronism with the regular hour and minute hands during the running of the timepiece or when the hands are being set. The regular hour hand makes two complete revolutions for each single revolution made by the special hand. Thus when hour hand 17 undergoes a full revolution from 12 midnight to 12 noon, the G.M.T. hand makes a half revolution.

The special hand 20 aets as a pointer with respect to a rotatable bezel 21 which is divided into 24 hourly intervals. While the conventional hands give local time in the customary fashion, the special hand gives Greenwich Mean Time or the time in any other zone. Thus, in setting the watch, once the owner has established the time differential between the time zone he is in and the second time zone desired, he then turns the bezel 21 until the proper value for the second time zone at midnight local time is opposite the 12 marker on the conventional dial 16.

For example, let us assume the timepiece shows 4 p.m. Eastern Standard Time and the second zone is to be Greenwich Mean Time (G.M.T.), which is five hours later. At midnight local time, G.M.T. would be 5 am., or 0500 hours. The bezel 21 is then rotated until its "5 marker is opposite the l2 marker on the inside dial. The G.M.T. hand 20 will now point to 2100 hours on the 24-hour bezel scale, which is the correct G.M.T.

We shall now consider the structure of the rotatable bezel and its associated sub-assembly elements in greater detail. The fixed bezel 10 is provided with an upwardlyextending cylindrical rim 10a over which is received a dome-shaped crystal 22, the inner surface of the crystal engaging the outer surface of the rim. The exterior surface of rim a is provided with a circular bead ltb which is accommodated within an annular groove formed on the inner surface of the crystal. The crystal is loeked into place on the rim 10a by a holding ring 23 which rests 'on the top surface of the fixed bezel 10 and surrounds Vannular' groove 27a formed thereon. Received within the groove is a flexible split annular friction washer 23' concentric with holding ring 23 and engaging the undersurface of trackway fiange 24. Received between the upper -surface of the trackway and the undersurface of the G.M.T. bezel 21 is an annular tension spring 29, which is shown separately in PIG. 3. The spring is formed of flat spring metal which is `corrugated to exert a uniformly distributed pressure between the undersurface of the rotatable bezel 21 and the upper surface of trackway flange 24.

Thus as shown in FIG. 2, the spring 29 raises the rotatable bezel 21 above the holding ring 23 and causes the friction washer 28 to slidably engage the undersurface of trackway flange 24. The edge 21a of bezel 21 is serrated to facilitate rotation, the set posit-ion of the bezel being maintained by the spring.

The split fiexible washer 28, as best seen in FIG. 4, is formed with a circular identation which defines a shoulder 28a which abuts the inner surface of the sleeve 27 of the rotatable bezel 27. The flexible washer is formed of spring metal and tends to expand outwardly, hence the washer is urged against sleeve 27a, and since the washer is positioned below flange 24 of the holding ring 23 and is reoessed within groove 27a in the rotatable bezel, the bezel 21 while free to rotate is nevertheless locked to Vring 23.

.27, the washer then being released whereby it expands so that its periphery falls into the annular groove 27a in the sleeve, at which point the sub-assembly component lock together to form a complete unit. In final assembly, the unit is pressed over the crystal 27, so that the holding :ring 23 of the sub-assembly locks the crystal onto the fixed bezel of the casing. In the event sub-assembly unit is defective and requires replacement, the entire unit can ,be removed .by dislodging the holding ring from the crystal.

The amount of tension on the rotatable bezel 21 is determined entirely by the tension spring 29 interposed between the bezel and the yholding ring 23, and this can be regulated as desired. Inasmuch as split washer 28 is urged against the sleeve 27 of bezel 21 with a spring force which overrides the frictional contact between the washer and the undersurface of fiange 24, when the bezel is turned, the washer is caused to turn with it. However, should this force be insufficient to overcome the frictional contact between the washer and flange 24, then the bezel will turn about the washer with satisfactory results, for in either event, the bezel is locked to the ring and cannot be removed without removing the entire sub-assembly, the tension on the bezel is that imparted by the tension spring and the frictional forces are such as to hold the bezel at its set position.

While there has been shown a preferred embodiment of a watch casing with a rotatable bezel assembly in acc'ordance with the invention, it will be appreciated that many changes and modifications may be made therein without departing from the essent-ial spirit of the invention as defined in the annexed clairns. It is also to be understood that while the invention has been described to provide readings simultaneously in two time zones, the rotatable bezel may be calibrated to operate in conjunction with the minute hand of the watch to provide elapsed time indications from zero to siXty minutes. Alternatively, the time indicia on the bezel may be made to run in the counterclockwise direction to give remaining time or count-down indications from a set starting time to zero time. By the use of a fourth hand adapted to move one increment per twenty-four hours, the outer bezel may be used as a date indicator, and in this case would be calibrated from 1 to 31.

What is claimed is:

ll. A watch casing for a watch Works having a special hand making one full revotution per twenty-four hours; said casing oomprising a fixed bezel for housing said works, a crystal mounted on said bezel to expose said special hand, and a removable sub-assembly constitu-ted by a holding ring surrounding said crystal to secure same in place, said ring having an outwardly extending fiange 'forming a circular trackway, a time-calibrated movable bezel encircling said crystal and having a downwardly eX- tending sleeve surrounding said trackway and provided on the inner surface with an annular groove, a split friction washer concentric with said holding ring and engaging the underside of said trackway, the periphery of said friction washer being received within said groove to lock said movable bezel to said ring, and an annular tension spring interposed between said traekway and said cali- .brated bezel, whereby the elements of said sub-assembly lock together to form a unit which is capable of being pressed over said crystal or of being removed therefrom in a single operation.

2. A Watch casing for a watch works having hour, minute and sweep second hands and a special hand making one full revolution per twenty-four hours, said casing comprising a fixed bezel for housing the watch works, said fixed bezel having a cylindrical rim, a dome-shaped crystal rece'iva'ble over said rim to expose said hands, and a removable sub-assembly constituted by a holding ring surrounding said crystal t-o secure same to said cylindrical rim, said holding ring having an outwardly eX- tending circular flange forming a trackway, a movable annular bezel calibrated in twenty-four hour increments encircling said crystal and having a downwardly extending sleeve surrounding said trackway provided on its inner wall with -an .annular groove, a split fricti-on washer concentric with said holding ring and slidably engaging the undersurface of said trackway, the periphery of said friction washer being received within said groove, whereby it moves with said calibrated bezel, and an annular tension spring interposed between said trackway and said calibrated bezel, whereby the elements of said sub-assembly lock together to form a unit which is capable of being pressed over said crystal or of being removed therefrom in a single operation.

3. A watch casing for a watch works having hour, minute and sweep second hands and a special hand making one full revolution per twenty-four hours, all of said hands being mounted above a dial, said casing comprising a fixed bezel for housing the watch works and having lugs eX- tending therefrom for attaching a strap there'to, a back enclosure for said fixed bezel, said fixed bezel having a cylindrical rim at the front thereof, a dome-shaped c-rystal receiv-able over said rim to expose said hands, and a removable sub-assembly constituted by a holding ring surrounding said crystal to secure same to said cylindrical rim, said holding ring having an outwardly extending circular flange forming a trackw'ay, a movable annular bezel calibrated in twenty-four hour increments encircling said crystal and having a d'ownwardly extending sleeve surrounding said traekway and provided with an inner 'annular groove, a split friction washer eoncentric with said holding ring and slidably engaging the undersurface 5 of said trackway, the periphery of said friction washer References Cited by the Examiner being received Within said groove, whereby it moves with UNITED STATES PATENTS said calibrated bezel, and an annul-ar |tension spring intreposed between said trackway and said calibrated bezel, 2'909893 10/1959 Flchter 58-90 whereby the elements of said sub-assembly look together 5 FOREIGN PATENTS to form a unit which is capable of being pressed over said 328 ,801 5/1958 Switzerland crystal or of being removed therefrorn in a single op- '336:019 3/1959 Switzerland: efaflon- 343,920 2/1960 Switzerland.

4. A casing as set forth in clairn 2 Wherein said spring ds constituted by a corrugated fia-t spring applying uni- RICHARDB' WILKINSON Pnmfl'ly Emmmer' form tension to said calibrated bezel. GERALD F. BAKER, Examiiner.

Claims

1. A WATCH CASING FOR A WATCH WORKS HAVING A SPECIAL HAND MAKING ONE FULL REVOLUTION PER TWENTY-FOUR HOURS; SAID CASING COMPRISING A FIXED BEZEL FOR HOUSING SAID WORKS, A CRYSTAL MOUNTED ON SAID BEZEL TO EXPOSE SAID SPECIAL HAND, AND A REMOVABLE SUB-ASSEMBLY CONSTITUTED BY A HOLDING RING SURROUNDING SAID CRYSTAL TO SECURE SAME IN PLACE, SAID RING HAVING AN OUTWARDLY EXTENDING FLANGE FORMING A CIRCULAR TRACKWAY, A TIME-CALIBRATED MOVBLE BEZEL ENCIRCLING SAID CRYSTAL AND HAVING A DOWNWARDLY EXTENDING SLEEVE SURROUNDING SAID TRACKWAY AND PROVIDED ON THE INNER SURFACE WITH AN ANNULAR GROOVE, A SPLIT FRICTION WASHER CONCENTRIC WITH SAID HOLDING RING AND ENGAGING THE UNDERSIDE OF SAID TRACKWAY, THE PERIPHERY OF SAID FRICTION WASHER BEING RECEIVED WITHIN SAID GROOVE TO LOCK SAID MOVABLE BEZEL TO SAID RING, AND AN ANNULAR TENSION SPRING INTEROSED BETWEEN SAID TRACKWAY AND SAID CALIBRATED BEZEL, WHEREBY THE ELEMENTS OF SAID SUB-ASSEMBLY LOCK TOGEHTER TO FORM A UNIT WHICH IS CAPABLE OF BEING PRESSED OVER SAID CRYSTAL OR OF BEING REMOVED THEREFROM IN A SINGLE OPERATION.