World watch

World watch with a single hand (9) comprising a watch mechanism in a case, a bezel (2) above the case, a face (3) and a hand (9), together with a back, said assembly forming an internal body which is mounted in a relatively easy manner within an external locking ring (6). The said ring is located in a peripheral groove (12) formed by the bezel (2) and the back. The body can be rotated in a stepwise manner, as it is locked in each position by means of a locking device comprising two bosses (13) on the locking ring (6) and slots (14) on the bezel (2). One of the attachments (7) carries a numeral (16) and the bezel (2) is provided with a mark (17). By rotating the body, the mark moves away from the stationary numeral. The difference, determined in hours on face (3) which carries no numbers, gives the time variation between different time zones throughout the world.

The invention relates to a world watch, that is to say a watch which is 
able to indicate to the wearer the time at any point in the world on the 
basis of the local time or which makes it possible to determine the local 
time at a given place which corresponds to a particularlocal time. 
So-called world watches are already known, but their disadvantage is that 
they are of a relatively complicated construction so as to be able to give 
the desired information. Furthermore, this information can only be 
obtained by selecting from a large number of different parts of the watch 
the particular part necessary for carrying out the requisite setting, 
which gives rise to incorrect operations and/or interpretations. 
One of these watches (Swiss Pat. No. 339,128) has a fixed case comprisng 
the watch mechanism with two normal hands and a normal face, the latter 
being surrounded by two rotary rings, whereof one which is called the time 
zone ring carries the inscriptions indicating the most important city for 
each time zone, whilst the other ring called the hour ring carries 24 
circles corresponding to the 24 hours of the day. As stated hereinbefore, 
these two rings rotate and can be actuated independently of one another in 
order to determine the local time in a random place in the world or the 
local time for a particular time determined in a given place. These two 
rings necessitate a relatively complicated case construction due to the 
sealing problems which occur. 
Another watch (Swiss Pat. No. 343,917) similar to that described 
hereinbefore has a rotary time zone ring which can be rotated by the ring 
flange and is located in an annular groove. It is therefore necessary to 
provide a special support in the case to receive this ring, as well as to 
provide a special axial position for the ring flange in order that it can 
not only drive the watch movement and the hands, but also said ring, 
without actuating the other parts of the watch during its rotation. 
Another world watch (Swiss Pat. No. 451,827) is known which is equipped 
with four hands. A rotary lunette can be rotated to determine the local 
time at the given place. However, the presence of four hands not only 
gives rise to confusion with regard to the local time, but it also 
significantly complicates the problems of said hands in the centre of the 
face, together with the individual driving thereof. 
Another watch (Swiss Pat. No. 504,033), whose construction is similar to 
the second of the prior art watches is equipped with a world time 
indicator in the form of a rotary transparent dome. In the same way there 
are problems in driving the dome and maintaining the necessary sealing in 
this construction. 
The present invention relates to a world watch which has a much more 
simplified and robust construction, which can be manufactured at a lower 
cost and which gives a clear indication of the desired time without giving 
rise to errors, thus obviating all the disadvantages mentioned 
hereinbefore. 
The world watch according to the invention is characterised by the 
characterising features of claim 1.

The watch comprises a conventional watch mechanism housed in a case (for 
reasons of simplification the known mechanism and the case are illustrated 
in FIG. 2 as unit 1), a bezel 2 encircling the face 3 and the glass 4 of 
the watch above the face 3, a back 5 and a locking ring 6, the latter 
carrying two diametrically opposite attachments 7 for the strap 8. 
The watch mechanism can be of any per se construction but only drives a 
single hand, i.e. that indicating the hours. 
As can be gathered more particularly from FIG. 3 the back 5 and the bezel 2 
are fixed by means of screws 10 (preferably four) which are inserted 
through bores 11 in back 5 and are screwed into corresponding bores 11' in 
bezel 2. The latter and the back 5 are thus joined together and surround 
between them the not shown case in order to form a single body located in 
a rotary manner (to be described hereinafter) in the locking ring 6 which 
is fixed to the attachment 7 fixed to the strap 8. 
Bezel 2 and back 5 are both provided with peripheral zones 21, 51 
respectively which, in the fitted state, form a peripheral annular groove 
12 whose bottom 12' has a diameter which is slightly smaller than the 
internal diameter of the locking ring 6. Thus, the latter is housed in 
said groove, preventing any relative movement in the axial direction of 
the watch, but which permits the relative rotation between bezel and back 
on the one hand and the locking ring on the other. 
To prevent body 1, 2, 5 rotating freely with respect to ring 6, a locking 
device is provided between the lower cylindrical portion 22 and the bezel 
2 (cf FIG. 3) and the inner surface 61 of ring 6. This device comprises 
two bosses 13, disposed in a diametrically opposite manner on said surface 
61 and 24 slots 14 regularly disposed along the periphery of cylindrical 
portion 22, whereby two of these slots 14 cooperate with the bosses 13. To 
rotate body 1, 2, 5 relative to the ring, it is necessary to utilise the 
elasticity of the material used for the bezel 2 and the ring 6, which 
permits a rotation under friction (between bosses 13 and the wall of the 
cylindrical portion 22) until two other slots come into contact with the 
bosses, thus locking the body in its new position. There are 24 slots so 
that the body can be rotated hour by hour to correspond with the time 
zones which, with due exceptions, always differ by full hours. 
Whitegold has proved highly satisfactory as the material which ensures the 
requisite elasticity without being too flexible and without being subject 
to too great wear caused by friction between the bezel and the ring during 
rotation. However, other materials can be used, provided that they meet 
the above-mentioned requirements. 
Obviously, the bosses 13 could also be provided on the cylindrical portion 
22 and the slots 14 on the locking ring 6. 
As can be gathered from FIG. 1, the upper attachment carries e.g. a roman 
numeral 16 and the locking ring 6 a mark 17 in the form of a coloured dot, 
a cavity, a relief or any other suitable configuration, said mark 
determining the extent of rotation with respect to numeral 16 and 
consequently the fixed part of the watch. 
Back 5 is provided with a recess or cutout 18 in order to receive the ring 
flange 19 (FIGS. 1 and 2). In the same way bezel 2 is provided with a 
cutout 23 which envelopes the upper part of ring flange 19. To enable the 
ring flange 19 to come into operation it projects downwards, i.e. with 
respect to the back 5. 
It is very easy to use the watch for determining the time in the different 
time zones. 
If it is desired to know the present time in a particular time zone and the 
time difference relative to the local time zone is known, for example 5 
hours behind, body 1, 2, 5 is rotated and with it the face and hand in the 
counterclockwise direction until the mark 17 is 5 hours from the fixed 
numeral 16. It should be noted that the face carries no numeral and that 
the particular time is determined solely by the position of the hand as is 
the case with normal modern watches which no longer display numerals. Hand 
9, which according to FIG. 1 indicates the local time of about 0115 hours 
(or 1315 hours) now points obliquely to the left and bearing in mind this 
known position and by means of the marks 31 on face 3 it is readily 
apparent that the local time in the said distant time zone is at present 
approximately 2015 (or 0815 hours). However, on moving to a time zone 
which is for example ahead the watch is firstly set by rotating the body 
in the clockwise direction until the hand 9 more or less corresponds with 
the clocks in the new time zone (the precise position of the hand can then 
be obtained by actuating the ring flange 19). It is then merely necessary 
to count the difference in hours between mark 17 and numeral 16 in order 
to know how many hours this new time zone is ahead of the original zone. 
The watch shown is particularly suitable with a view to successive 
introduction of the summer time into certain countries, which creates a 
certain confusion as regards to the local time from one country to the 
next on crossing a frontier. 
As is apparent from what has been stated hereinbefore, the world watch 
shown has no internal part which has to be adjusted from the outside (as 
is the case with the prior art) with the exception of the hand which must 
be adjusted from the outside as all watches. Thus, the sealing problems 
are the same as in conventional watches and can be solved in the same way, 
without additional difficulties.