Chronoswiss is a small company producing a distinctive line of watches. The watches are easily recognized for their wonderfully done guilloche dials, their onion crowns, and coin-edged cases. The company has also specialized in a number of under-the-dial complications, as well as some modestly priced skeletonized pieces. The Delphis, with both jumping hour and retrograde minutes, is arguably their most interesting and original piece. Seconds is displayed in a traditional manner at six o’clock, providing three different methods for displaying time.

The Delphis is based on the Chronoswiss caliber 122, a 21,600 beats-per-hour automatic. The simple movement is a 12 ligne (26.80 millimeter) design and 5.30 millimeters in height. With jumping hour and retrograde plate, the movement is known as the caliber 124 and thickens to 6.9 millimeters. The original 29 jewels are augmented with an additional two on the jumping hour mechanism, for a total of 31. Both movements utilize a Glucydur balance and Nivarox grade I spring, as well as Incabloc shock protection for the balance.

The caliber 122 is now a Chronoswiss movement. It derives, however, from the Enicar caliber 165, first released by Enicar in 1967 as their first in-house automatic. Chronoswiss provides significantly better top-plate finishing than Enicar ever did, and reveals this through the display back of the watch. Chronoswiss has also made some significant technical changes to the movement. For example, the original bidirectional winding has been converted to a unidirectional system by Chronoswiss. A number of other details show changes from the original movement.



While the case, dial, and top plate provide a handsome watch, the under-the-dial mechanism is the most technically novel part of the watch. The under-the-dial view, without disassembly, is shown (right).  The hour ring (with the Chronoswiss logo at midnight) is clearly visible.








Removal of the center plate and hour ring reveals the mechanism responsible for both jumping hours and retrograde minutes. Components include (1) the wheel-like jumping hour-retrograde plate; (2) the jumping hour lever and attached hour wheel pawl (2A); (3) the retrograde spring lever; (4) the retrograde spring; and (5) the minute hand pinion. The bottom plate of the movement (visible through the complication plate), the complication plate itself, and operating components shown only minimal finishing.


The jumping hour and retrograde minute hand mechanism reveal a remarkably simple and clever design. A snail cam (1) is driven by the movement. The outer edge of the snail cam rides on the edge of a plate (3A) riveted to the jumping hour lever (3). Driven by the snail cam, the rack (3B) of the hour lever rotates the minute hand pinion (2). The minute hand pinion, in turn, drives the rack of the spring lever (4), which compresses the retrograde spring (5).




During running (right), the movement of components is illustrated by the blue arrows. The minute hand pinion (2) is, of course, turning clockwise, for it is carrying the minute hand.





The far tip of the retrograde hour lever (3) moves counterclockwise during running, it’s pawl (6) sliding over the notches on the underside of the hour ring (inset). Correct operation of the jumping hour pawl is dependent on very precise adjustment of spring (7). Hour advance was occasionally unreliable in the sample I inspected until I reshaped the tip of the hour pawl and carefully adjusted the spring




When the trailing tip of the snail cam clears the tip of the jumping hour lever (right, arrow), both jumping hour and minute-hand retrograde operations are set into motion. Note the liberal quantities of molybdenum grease on the high-load snail cam.







No longer held by the snail cam (via the hour lever {3} and minute pinion {2}), the spring lever (4) suddenly jumps clockwise. This rotates the minute pinion (2) counterclockwise, resetting the minute hand. The minute pinion simultaneously rotates the hour lever (3) clockwise. The pawl at the far end of the hour lever pushes the hour ring forward by one hour. (A separate jumper spring assures correct indexing of the hours.)


The Delphis offers a nicely-made, large (38 by 11 millimeter) case, a beautifully executed dial, and display functions unavailable elsewhere. It is, taken on the whole, a decent execution of a novel idea that speaks to many horological traditions.

Chronoswiss has always attempted to offer good value in its watches. In terms of complications of this type, the Delphis has no competition at anything close to its price. Personally, I would have wished for better functional finishing of the complication plate, and a more assured design for tensioning of the jumping hour pawl.    

© 2012 Bourne In Time Inc.