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Just as an
individual winding his or her watch senses the increasing turning resistance of
the crown as the watch is being wound, the microprocessor "brain" of the SEMPRE
winder monitors the electrical current drawn by the gear motor as it rotates.
The amount of force required to wind the mainspring of a mechanical watch, known
as the winding torque, increases as the watch is being wound. As the torque
increases, the drive motor draws more current. The control circuit is
user-adjustable to shutdown the system when it senses that the current has
reached a pre-set limit, one which is well below the maximum torque that the
watch mainspring can handle. To prevent "overbanking" the drive reverses the
crown momentarily after shutdown.
For safety
purposes, the drive system is fitted with a mechanical slip-clutch which
has been factory set to slip at a safe torque in the event of a microprocessor
failure. This redundancy eliminates any possibility of stressing or breaking the
mainspring of an expensive and, perhaps delicate, mechanical watch.
In
operation, the winder automatically turns on every twenty-four hours. Upon
actuation, the drive motor begins rotating the collet for 8 minutes. With the collet rotating at approximately 6
rpm, this provides a maximum of 48 crown rotations per day. However in
practice, the actual number of rotations is controlled by the current feedback
circuit whose priority is to shut down the motor based on torque, rather than by
time.
 Interestingly,
the SEMPRE winder will also wind "self-winding" automatic watches. The winding action of an automatic watch differs from a
hand-wound mechanical watch in that there is a built-in slip-clutch in the
mainspring mechanism watch to prevent over winding rather than a finite stop as
in a hand-wound. In this case, the timing circuit of the SEMPRE comes into play
as there may not be enough current draw increase to signal the system to
shut-down automatically. Either way, this hybrid control circuit provides
redundant safety for winding any type of mechanical watch; hand wound or
automatic.
In use,
after the proper collet has been selected, the watch is placed in position on a
mounting "shuttle" which supports the watch both horizontally and vertically.
All contact points are non-metallic, protecting the finely finished watch
surfaces from scratching or abrasion. Using a provided "spacer" even allows
watches with screw-down crowns to be wound safely and conveniently. Many hand
wound pocket watches can be accommodated with this system by using the supplied
extender kit.
Owners of
fine hand wound or automatic mechanical watches with numerous complications will
find the SEMPRE watchwinder ideal for keeping their watches continuously wound
and "exercised." Operating by battery, the winder can be stored in a safe for 10
to 12 months without attention. Alternately, the winder may be powered with the
high quality "switcher" type AC/DC converter supplied with each unit, which
operates at any voltage from 90 to 240 VAC, 50 or 60 hertz and provides perfect
6 VDC.
The winder
is housed in an elegant maple burl veneer case with an plate glass viewing
panel. The case is provided with a solid brass, gold-plated lock whose fold-up
latch also serves as a lifting handle. All hardware is also solid brass, with
all exposed parts gold-plated and lacquered for durability. An extension kit is
also supplied for use with pocket watches up to 60mm diameter.
For details of the
2 patents governing the Sempre watchwinder mechanism (Patent Nos. 6,439,761 and
5,988,871) click here. International patents
pending.
An extended 3-year warranty is
available on this model - click
here for details.
News....Orbita
is now winding the world's most complicated watch. Click for details.
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The
SEMPRE