Horology: time measuring systems or devices – Cases – Of particular material
Patent
1999-04-29
2000-08-15
Miska, Vit
Horology: time measuring systems or devices
Cases
Of particular material
G04B 3700
Patent
active
061025631
DESCRIPTION:
BRIEF SUMMARY
The invention pertains to a case for wrist watches having a case which houses the clockworks therein and which is closed on the top by a glass piece and on the bottom by a cover.
BACKGROUND
Cases for wrist watches are known in a wide variety of embodiments.
It is also known that highly tempered corrosion-resistant objects such as knives, scissors, surgical instruments, tools etc. can be manufactured inexpensively on conventional machines and by hardening afterwards using steel with the following composition:
______________________________________ carbon: 0.6-2%
chromium: 16-25%
tungsten: 1-7%
molybdenum 0.2-2%
vanadium: 0.2-3%
traces of iron.
______________________________________
The object of the invention is to provide for a case that possesses a high degree of functionality and stability.
SUMMARY OF THE INVENTION
In order to solve this problem, a case for a wrist watch which encloses a clockworks is made of a hardenable, nickel-free stainless steel with a carbon content greater than 0.4% and a chromium content greater than 12%, molybdenum greater than 0.2% and vanadium greater than 0.2%, manufactured by machining from a solid material and hardened afterwards, and that a ring which encloses the clockwork in the case is made of a diamagnetic metal material.
According to the present invention, at least the case element, but preferably also the outer cover that closes the case on the bottom is made of a hardenable, nickel-free stainless steel that has a carbon content greater than 0.4% and, in alloy, a chromium content greater than 12%, a molybdenum content greater than 0.2% and a vanadium content greater than 0.2%.
The temperable or hardenable steel preferably belongs to the group X110 CrMoV 15 or X105 CrMo 17.
In addition, a case-hardenable steel is suitable for the manufacture of the outer part of the case and/or the cover that has a carbon content greater than 0.1%, preferably between 0.1 and 6%, a chromium content greater than 12%, a tungsten content greater than 1.0%, a molybdenum content greater than 0.2%, a vanadium content greater than 0.2% and a silicon content greater than 0.2%.
Although the aforementioned steels can be processed in an unhardened state by conventional means and on conventional machines in a relatively simple and inexpensive manner, and after tempering a very robust, hard watch case is obtained, these materials have heretofore been regarded by experts as fully unsuitable for the manufacture of clock cases and especially for wrist watches, due to the fact that the aforementioned hardenable steels are without exception highly magnetizable, especially by external magnetic fields, so that they function as permanent magnets that strongly impair the very sensitive clockwork of a wrist watch. Other technologies are thus used to obtain highly hardened watch cases; these cases are manufactured from ceramics, which is, however, an expensive and complicated process.
The invention is based on the realization that the aforementioned hardenable steels surprisingly are suitable, in spite of their being magnetizable, also for wrist watch cases, if in the interior of the case the ring surrounding the clockwork also is made of the diamagnetic metal. It has been shown that by means of this ring the part of the case interior that houses the clockwork can be kept free from a magnetic field that would impair the functioning and accuracy of the clockwork.
Further embodiments of the invention are the subject of the dependant claims.
BRIEF DESCRIPTION OF THE DRAWING
In the following, the invention is described in more detail by way of an example embodiment with reference to the figure. The figure shows a cross-section in simplified depiction of a case according to the invention for a men's and/or ladies' wrist watch, together with a clockwork located in this case.
DETAILED DESCRIPTION
In the figure, 1 is the outer case of a men's and ladies' wrist watch, in which the clockwork 2 with the hands 3 and the face 4 is housed and which is closed tightly on the top, shown at t
REFERENCES:
patent: 4433921 (1984-02-01), Gogniat et al.
patent: 4561783 (1985-12-01), Lederrby
LandOfFree
Case for wrist watches does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Case for wrist watches, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Case for wrist watches will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1999931