Watch case

Case of an early pocket watch

A watch case (synonymous with shell, English case , French boîtier ) is a case to protect the clockwork of watches from house dust and moisture. Watch cases are made by shell makers.

history

various marks on watch cases

Watch case from the Fürstenberg porcelain manufactory , around 1760

While the cases of stationary clocks are traditionally mostly made of materials such as wood , chrome-plated brass or steel , gold-plated bronze or glass , less sensitive materials or precious metals are mainly used for wristwatches and pocket watches .

The pocket watches of the 18th and 19th century, the housing usually consist of gold - or silver alloys , mostly to indicate the fineness with a corresponding fineness temple were hallmarked.

At the beginning of the 1920s, new materials such as aluminum , platinum , titanium or Staybrite (at that time the commercially used name of the stainless steel type X12CrNi18-8 (Inox), also known as 1.4300 or V2A) were added. Today the vast majority of cases for wristwatches are made of stainless steel.

The 1931 developed Reverso by Jaeger-LeCoultre allowed to contact the watch case to the sensitive among others the Polo games watch glass of mineral glass to protect. This type of housing is therefore called a reversible housing .

The first wristwatch with a splash-proof case was the Rolex Oyster in 1926 . The water resistance of watch cases is now defined in the standards DIN 8310 September 2010, ISO 22810 and NIHS 92-20.

The first wristwatch with waterproof case was 1953, the diving watch Fifty Fathoms of Blanc Pain , which is a water-resistance up to a depth of 50 fathoms guaranteed, according to 91.45 meters or approximately 9 bar pressure difference . Since it is more difficult to transmit sound underwater, a second, perforated case back ( sound bottom ) can be placed in front of the outside of diver's watches with an alarm in order to avoid dampening by the wrist, for example with the Polaris by Jaeger-LeCoultre from 1968. Some diving watch cases also contained a diaphragm for a depth gauge , e.g. B. the Bathys from Favre-Leuba from 1966. The water resistance of diving watches is defined in the standards DIN 8603 September 1983 and ISO 6425.

Within the watch case that can movement for shielding of magnetic fields in an additional shell made of Permalloy are applied to the transition error to reduce, for example in the Omega SA British RAF 6B / 542 anti-magnetic (1953) and the early RailMaster series, the IWC Ingenieur (1955), the Rolex Milgauss (1956) and the Geophysic from Jaeger-LeCoultre (1958).

In small series you can also find cases made of technical ceramics , precious metals such as palladium or tantalum , and metal alloys under brand names such as Magic Gold , Zalium or Alchron , some of which are manufactured using powder metallurgy .

Watch case

The case of wrist watches are mostly made up of several components, however, single-watch case are as monocoque -Uhrengehäuse referred. A case of a wristwatch usually consists of the case back, the main case with the lugs, the bezel (synonymous bezel ) and the watch glass . The housing can be designed in various forms, e.g. B. round, upright rectangular , square, transversely rectangular, barrel-shaped ( tonneau ), oval or polygonal.

Since the introduction of sapphire glass , see-through glass backs have increasingly been used to provide a view of the movement . The lugs on the watch case are used to attach the watch strap and, depending on the design, are called straight, curved, wedge-shaped, concealed, cow horn-shaped, tear-shaped or crab-claw-shaped lugs.

Pocket watch case

The case of a pocket watch usually consists of a case back, occasionally a dust cover, a middle part, followed by the watch glass and the bezel, and occasionally also a case cover. The middle part is the circlet in which the clockwork is attached. Depending on its profile, the middle part is referred to as a tub, case, tub with protrusion, half tub, empire, directoire, baguette (synonym necklace), knife shape, pressed shape, angular shape, bug shape.

Housings of pocket watches with an additional hinged or popping cover over the watch glass are referred to as hunting cases (synonymous capsule watch , French savonnette , English hunting case ). Pocket watches with cover and with the elevator shaft at a right angle with the "12" and the second hand have as Savonnette - caliber designated movements . Movements in pocket watches with the winding shaft in a line between the “12” and the second hand are called Lépine calibres. In Lépine -Kalibern the use of a second was by design work plate with pillars by use of Kloben be replaced, allowing the construction flatter watches, z. B. Tailcoat watches .

literature

• Otto Böckle, Wilhelm Brauns: Textbook for the watchmaking trade. Work skills and materials. 8-10 Edition. Wilhelm Knapp, Halle (Saale) 1951 (reprint, edited by Michael Stern. Heel, Königswinter 2010, ISBN 978-3-86852-288-4 ).
• Hermann Brinkmann: Introduction to watchmaking (= The watchmaking school. Vol. 2). 10th unchanged edition. Wilhelm Knapp, Düsseldorf 2005, ISBN 3-87420-010-8 .
• George Daniels : Watchmaking. Updated 2011 edition. Philip Wilson Publishers, London 2011, ISBN 978-0-85667-704-5 .

Individual evidence

1. ^ GA Berner: Illustrated specialist encyclopedia of watchmaking (electronic version), keyword 'shell'. Retrieved April 20, 2012.
2. ↑ GA Berner: Illustrated specialist encyclopedia of watchmaking (electronic version), keyword 'watch case'. Retrieved January 9, 2013.
3. ↑ GA Berner: Illustrated specialist encyclopedia of watchmaking (electronic version), keyword 'Sprungdeckeluhr'. Retrieved March 19, 2013.
4. ^ GA Berner: Illustrated specialist dictionary of watchmaking (electronic version), keyword 'Lépine (Jean-Antoine)'. Retrieved March 19, 2013.