COSC

The Contrôle officiel suisse Chronometer, usually abbreviated COSC, the official Swiss Chronometer Control Authority. Is in their present form as the five " watches cantons " Bern, Geneva, Neuchâtel, Solothurn and Vaud worn together with the Federation of the Swiss Watch Industry FH association under Swiss law (Art. 60ff. Civil Code) with seats in Biel, Geneva and Le Locle them. They had emerged from the amalgamation of several private and semi-public laboratories since 1973.

Despite the name contained in the term " official" and their state collective members the COSC is not a public body and no state-certified inspection body, but a non-profit organization recognized self-regulation, the watch manufacturer.

The certification process

The COSC awards - as the name already says - Quality certification for chronometer on the basis of a standardized measuring method according to NIH 95-11 / ISO 3159th

This test is a mechanical clock lasts 15 days, during which the response of the plant in five different positions is determined at three temperatures. The tests are as follows:

• 2 days left crown at 23 ° C
• 2 days crown above at 23 ° C
• 2 days down crown at 23 ° C
• Dial down two days at 23 ° C
• 2 days dial up at 23 ° C
• 1 days dial up at 8 ° C
• 1 days dial up at 23 ° C
• 1 days dial up at 38 ° C
• 2 days left crown at 23 ° C

All exams will take place relative humidity about 24%. After every 24 hours, the deviation is measured, raised the plants and readjusted. On the tenth day of the tests are optionally present complications, such as a chronograph, turned on, to determine the behavior of the gear accuracy.

After passing the examination, the factory receives a certificate attesting to its accuracy. It contains the following information:

With quartz movements the exam lasts 11 days and apply the following values:

Maintains the work of a clock, the COSC certificate, the manufacturer provides the clock usually with the word chronometer.

Despite the generally high reputation of the COSC and the wide acceptance of their certificates, there are also well-known watch manufacturers, including famous names such as Jaeger- LeCoultre, IWC, Breguet and Piaget, who are the COSC critical and their watches for various reasons deliberately not certified ( neutral or negative ), although they meet the requirements, usually without problems.