Horology: time measuring systems or devices – With calendar indicator – Movable ring or disk
Patent
1992-07-29
1994-07-05
Roskoski, Bernard
Horology: time measuring systems or devices
With calendar indicator
Movable ring or disk
368 28, G04B 1924
Patent
active
053274016
DESCRIPTION:
BRIEF SUMMARY
The present invention concerns a wristwatch with a date display in a window on the watch face.
This type of watch with hands, which also indicates the date displays the date either by using an extra hand which points to the thirty-one days of the month arranged in a circle concentric to the hands, or by using a ring showing the thirty-one numbers, in which case the ring rotates for one step each day which equals 360.degree. divided by thirty-one, so that one number appears in a window formed by a rectangular opening on the watch face.
Date display devices are currently equipped with suitable correction means. Theoretically, one of the three positions for the time setting stem is for date correction. When using the watch, the wearer corrects the date until the correct number is displayed. Then during normal use, the watch causes either the hand or the disc to advance one step at midnight so that the correct date is always displayed. In the case of a month which is not a thirty-one day month, the user makes the necessary correction.
The main drawback of such watches is that the small number size affects legibility, especially in womens' watches.
The arrangement of thirty-one numbers on a date indicator ring limits number height to 1/31st of the ring circumference which, for any given radius, imposes a practical limit on number height. This height limitation has been overcome fairly successfully by adding an optical device to the watch glass such as a magnifying lens.
The prior art has proposed multiple solutions, mainly for the system using two contiguous concentric discs, one for displaying double digit and one for single digit numbers. The complexity of these mechanisms and the unattractive appearance of the gap which always remains visible between the two discs have limited the application of this solution.
Solutions using connectors or hooking flexible rings have also been proposed, but in practice are seldom used because they are complex and unreliable.
The present invention proposes overcoming the foregoing disadvantages by providing an effective means of date display which is easily visible and dependable.
To achieve this, the watch according to the invention is characterized in that it comprises a rotatable disc having at least a first series of numbers corresponding to one portion of the thirty-one dates and at least one second series of numbers corresponding to the remaining dates, in that these two series of numbers are arranged on at least two concentric circles, and in that it comprises a mechanism for driving said rotatable disc designed to selectively and automatically move the numbers from the first and second series to the window.
According to an advantageous embodiment, one of the concentric circles has the fifteen even numbers from two to thirty and one blank space, and the other circle has the sixteen odd numbers one through thirty-one, and the numbers on the two circles are arranged so that the chronological order corresponds to a sequence of numbers alternating between the two circles.
Preferably the fifteen even numbers and the sixteen odd numbers are arranged in chronological order on the two respective circles, with the transition from one date to the next corresponding to a 1/32nd disc rotation.
In this embodiment the fifteen even numbers are arranged in this order: 2-24-14-4-26-16-6-28-18-8-30-20-10-22-12 and the sixteen odd numbers in the order 1-23-13-3-25-15-5-27-17-7-29-19-9-31-21-11, with the transition from one date to the next corresponding to one 3/32nd disk rotation.
According to a particularly advantageous embodiment, one of the concentric circles has n numbers arranged in continuous chronological order and the other circle has the next remaining 31-n numbers also arranged in continuous chronological order.
Preferably, the numbers of one series situated on the inside concentric circle are located on a radius of the rotatable disc passing through the middle of the interval separating two numbers in the other series of numbers located on the exterior concentric circle.
In t
Besson Rene
Vernay Frank G.
Montres Rolex S.A.
Roskoski Bernard
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