Ebauches SA, Pre-475A, P1-V1 Prototype, 1954
Category: proof of principle, functional prototype
Description: Symmetrical, stainless steel cased prototype. Stainless steel snap back with no engravings, but with two recesses, one for each ‘crown’ tube. Cream coloured dial with raised, gilt 5min baton indexes, black printed ‘Swiss’ at ‘6’. Gilt hands and original acrylic crystal. Gilt, base metal crown. Additional metal plug for battery recharging at ‘9’, covered with original white plastic, protective cap.
Dimensions: 35.4mm (without crowns), lug – lug: 43.4mm, lug – lug, lug width: 18mm
Movement: Pre – 475 P1 Prototype movement, unumbered
Additional info: This piece represents one of the two versions of the earliest known Swiss made battery driven wrist watch. The caliber identification was not yet defined, but as the next generation of prototypes is named 475, it seems appropriate to call it ‘Pre-475’. This appears to be the first variant (V1) of this caliber, being alimented by one, large rechargeable battery. The plug for recharging the battery shows its original plastic, protective cap. The definitive version will have a metal cap, resembling a winding/setting crown with a raised ‘lightning’ symbol.
As mentioned in the parent section, one other version of the same caliber would be alimented by a ‘normal’, small battery located in a adjacent metal link to the case (P1-V2) and later inside the case back (P2-V2), that would become the Version ‘B’ for ‘Battery’. Although featuring an identical caliber, the V2-version lacks the connection with the recharging plug and the ‘hook’-like protrusion near the balance to make contact to the battery.
Although it seems that this prototype might be the first ever wrist watch with rechargeable battery, there is evidence which suggests, that Elgin had access to comparable technology or even more advanced technology around the same time period. @elgindownunder‘s research shows, that publications exist, where a solar powered watch was presented by Elgin in 1955 and that Elgin had access to an ‘atomic’ battery in 1957. It is well possible, that Elgin skipped the application of a ‘simple’ rechargeable battery to concentrate on more sophisticated and durable systems and thus never developed such watch. Neither the solar watch nor the ‘atomic’ version were marketed. In 1963 also the CEH in Neuchâtel will research the possibility of a miniaturised ‘nucelar’ alimentation of a wrist watch. Fortunately the research on that system was abandoned one year later.
Provenance: Ex Hans Baumann collection
Published: Bramaz H.-R., Baumann H.; Die Elektrische Armbanduhr, Band 1, Verlag Stutz Druck AG, Wädenswil, 2013, page 44, picture 2
Electric Watch Prototypes 