FHF 691 (Standard)
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| FHF 691 (Standard) |
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Description
The "Standard" caliber 691 of the Fabrique d'Horlogerie de Fontainemelon
bases on the common
FHF caliber 69 and
added a center second hand to it.
Since the available space is very low on these form movements, the FHF had to use
an extraordinary solution: The fourth wheel indirectly drives a wheel on the
top of the main plate, which itselfs drives the center second pinion.
The rest of the caliber 691 is identical to the FHF caliber 69.
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| Center second hand driving mechanism |
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| dial side view |
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Technical data
| Manufacturer | FHF |
| Caliber | 691 (ST) |
| Number of jewels | 17 |
| Escapement | Anchor with pallets |
| Balance | Nickel |
| Shock protection(s) | Incabloc |
| Balance cock direction | counterclockwise |
| Hairspring stud | moveable |
| Regulator type | Fonto |
| Movement construction | Fork
Escapement wheel, Fourth wheel, Third wheel, Center wheel
Center second pinion
Mainspring barrel |
| Features | SCI |
| Functions | Hour, minute, second |
| Beats per hour | 21600 |
| Size | 61/4 x 8''' |
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| Factsheet |
Usage gallery
