Ebosa 22
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| Ebosa 22 |
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Description
The Ebosa 22, which debuted in the early 1950ies, is a remarkably well made
swiss
pin lever movement, of
Roskopf type, which shows
some interesting details.
Besides that, it belongs to the small group of pin lever movements, which are
also esthetically pleasant, since it has got a stripes decoration and
nickel silver coated plates.
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| inside view: gears |
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As common on Roskopf movements, the giant mainspring barrel overlaps the center of the
movement. Here, the maximum available space was perfecly used, which is very positiv for
precision and power reserve.
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| gears |
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The clever arrangement of the gears optimally uses the free space of this large,
massive made movement with its large diameter of 11 1/2 lignes.
You can see here the Roskopf construction very well: There's no center minute wheel,
but a large driving wheel, which is driven by the mainspring barrel. The cannon pinion
and the hour pinion are driven on the dial side by the exchangement wheel, which sits
with a friction coupling on top of mainspring barrel.
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| main plate |
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On the Ebosa 22, all bearings contain synthetic rubis, which reduce friction and
wear and thus lead to higher precision and longer power reserve times.
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| escapement wheel bearing |
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a very interesting detail is the adjusting mechanism for the escapement wheel bearing. In the
fifties, this was history long ago, since it was once used as a simple tool for adjusting the depthing
of the pin lever. Its disadvantage is, that it's possible, that the escapement wheel axle is no longer
at right angle to the bearings, which leads to additional wear of the pivots. At the end of the 19th
century, such a mechanism was required to increase the low precision of the cheap made Roskopf movements.
Why Ebosa still used that technique is unknown, but it's quaint nevertheless.
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| side view of balance |
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Another odd detail concerns the "screw" balance, which is surprisingly small, is non-shock-protected
beared, beats with Roskopf-unlike 18000 A/h and whose hairspring key contains a long regulator arm: The
"Screws" are in quotes, since they are not screws, but only imitations, consisting of a half circle.
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| balance bottom |
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On the down side of the balance wheel, you see, that the half-circles are no screws at all! But they look
nice, though...
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| dial side view |
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On the dial side you see the well made yoke winding system - this is also uncommon for pin lever
movments. Unlike on other Ebosa movement, there's even a true yoke setting lever spring used!
At "12" you see, how the hour wheel is connected with the exchangement wheel of the mainspring
barrel. That's typical for a Roskopf movement.
Technical data
| Manufacturer | Ebosa |
| Caliber | 22 |
| Number of jewels | 15 |
| Escapement | pin lever |
| Balance | Nickel screw balance |
| Shock protection(s) | none |
| Balance cock direction | counterclockwise |
| Hairspring stud | fixed |
| Regulator type | Long regulator arm |
| Movement construction | Fork
Escapement wheel, Fourth wheel, Third wheel, Large driving wheel
Mainspring barrel |
| Construction type | solid construction |
| Bridge shape | bear shape, 3 visible gears |
| Winding mechanism | yoke |
| Setting lever spring | 2 holes |
| Features | s |
| Functions | Hour, minute, small second |
| Beats per hour | 18000 |
| Size | 111/2''' (measured: 25,3 mm) |
| Image in Flume Werksucher | 1952 23 |
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| Factsheet |
Usage gallery
