Patek Philippe 5101 Bedienungsanleitung Seite 3

Introduction
The Reference 5101 is the only wristwatch that
combines a tourbillon with the remarkable power
reserve of 10 days. Its magnificent, slightly cambe-
red art deco case is unique as well.
Reference 5101
Caliber TO 28-20 REC 10J PS IRM
Manually wound wristwatch. Tourbillon.
10-day power reserve indicator. Subsidiary seconds.
The Tourbillon
In the 18th century, inquisitive minds discovered
that the spring of the movement's balance – the
reciprocating wheel that regulates watches – has
an intrinsic error. Since the center of gravity of the
helical spring does not precisely coincide with the
geometric center, the regularity of its oscillations is
affected by the earth's pull as soon as the watch is
moved out of the horizontal position.
The tourbillon corrects this phenomenon because it
suspends the balance wheel and balance spring in a
cage that rotates about its own axis once a minute.
This causes the slightly offset center of gravity of
the spring to rotate about the central axis once a
minute as well. Thus, irregularities of the spring's
oscillations due to the orientation of the watch are
automatically compensated.