Horology: time measuring systems or devices – Cases – With protection means
Reexamination Certificate
2000-11-15
2002-06-18
Miska, Vit (Department: 2859)
Horology: time measuring systems or devices
Cases
With protection means
C294S202000
Reexamination Certificate
active
06406178
ABSTRACT:
The present invention concerns a device for assembling a cover or a cap made of hard material on the upper edge of the middle part of a watch case.
In a wristwatch case the visible parts, i.e. the crystal, the middle part and the cover are the parts most exposed to outside attacks, such as scratches, shocks, oxydation, etc. In high quality products, the non esthetic consequences of such attacks on the crystal are removed or reduced by using a sapphire glass the manufacture of which is difficult, but whose simple geometric shape does not involve complicated machining, For the other external parts, it has long been proposed to use a very hard material, such as a ceramic material. Such material has remarkable resistance to external attack, but has the drawback of still being sensitive to shocks and being very ill suited to very complex machining. For this reason, this hard material is most often used as an exterior part for a subjacent structure which is easier to machine and generally less expensive.
In order to secure the structure and exterior part to each other, the most obvious solution is bonding, as described for example in Swiss Patent No. 517 963 published on 29.02.1972. This document proposes, for a solid slightly machined cover, or for a thin coating, inserting a glue joint between the opposite surfaces. In order to obtain optimum cohesion, the surfaces must be sufficiently large and have excellent surface evenness, of the order of {fraction (3/100)} which requires minute rectifying operations. It is clear that such assembly by bonding no longer allows the part made of hard material to be replaced in the event that a shock removes a chip thereof. This same drawback is found in a variant of the method proposed in Swiss Patent No. 506 826 consisting in arranging a space between the cover and a case element, then filling it with a cement forming product.
In order to allow such a cover of hard material to be dismantled and replaced, Swiss Patent No. 508 925 propose fixing the cover to an element of the case in a removable manner by providing two grooves facing each other between which a closed elastic ring is inserted which will be compressed during assembly. If the cross-section of the ring is too large, the cover is liable to be broken by forcing it during assembly: if, conversely, the cross-section is too small, the cover is liable to rotate around the middle part which may be inconvenient for the passage of the time-setting stem, or non esthetic if the cover is not perfectly circular.
In order to overcome the above drawback, Swiss Patent No. 568 040 propose arranging blind holes radially in the bottom flat face of the cover, filling these holes with a material which can easily be threaded, and screwing said cover onto an element of the middle part. The proposed solution allows replacement of said cover to be envisaged, if necessary, and provide better positioning relative to the two assembled elements, but such a construction is relatively complex and the blind holes undeniably weaken said cover.
Other constructions are more of less linked to those mentioned hereinbefore and have the same drawbacks.
The object of the present invention is thus to overcome the drawbacks of this prior art by providing a device for assembling a cover made of hard material onto the upper edge of the middle part of a watch case or onto a part secured thereto, said cover being able to be obtained with a smaller number of machining operations and being able to be easily replaced in the event of breakage.
The invention therefore concerns a removable device for assembling a cover made of hard material onto the upper edge of the middle part of a watch case closed by a crystal and a back cover delimiting with a casing ring, a space for housing at least a movement, characterised in that it includes a metal centre whose outer wall has a stair structure complementary to the inner structure of the cover secured to said centre by means of at least two screws passing through it via holes to tighten clamps housed in radial hollows formed in a vertical wall of the cover, by compressing an elastomeric gasket arranged between two horizontal surfaces of the stair structures, and whose thickness is sufficient to arranged clearances at least between opposite surfaces respectively of the back cover and the base of the cover, and the vertical wall of the centre and the wall of the cover joining the base.
REFERENCES:
patent: 3643423 (1972-02-01), Piquerez
patent: 4034552 (1977-07-01), Davidson
patent: 4740935 (1988-04-01), Gogniat
patent: 5490123 (1996-02-01), Biver
patent: 311861 (1956-02-01), None
patent: 667966 (1988-11-01), None
patent: 2231042 (1974-12-01), None
Bach Michael
Lüscher Denis
Vuillaume Eloi
Vuillaume Fernand
Miska Vit
Montres Rado S.A.
Sughrue & Mion, PLLC
LandOfFree
Device for assembling a cover made of hard material on the... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for assembling a cover made of hard material on the..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for assembling a cover made of hard material on the... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2890994