CH238868

PATENT SPECIFICATION N°238868

NOVEMBER 18, 1943, 6 p.m, Class 71c

Uhrenfabrik Buren AG, Büren, (Switzerland).

Clockwork with center seconds hand.

Clockwork with center seconds hand. The present invention is a movement with a second hand in the middle, in which, the minute shaft has two bearings and the fourth wheel is coaxial with the axis of the second hand.

There are already movements of this type in which the . Fourth wheel is arranged between the middle cock and an auxiliary cock attached to the barrel bridge. In addition to enlarging the clockwork thickness, this arrangement also requires the arrangement of an additional part, namely the auxiliary cock.

An increase in the thickness of the clockwork has already been avoided by the fact that the hollow minute shaft was only mounted on one side, namely by a bearing in the plate. As a result, however, the well-known disadvantages of cantilever mounting were accepted. As usual, the barrel bridge and central cock are roughly on the same level, which is also the case with the first known type mentioned.

Olympic

Cal. 525

In August the technical director of Buren watch got the order, to develop a self winding watch. In October 1945 ten watches were tested by wearing. In December 1945 the direction decided to produce the watch - the cal. 525.

But only a few time later the reality showed, the winding mechanism was not efficiently enough, because the moving angle was to small. It has 15 degree only. In the following, the bumper has been improved, but with no success.

The production of this caliber stopped in 1949. It was produced for four years only and it is one of the rare movements of the bumper era, which is winding the barrel spring by both sides of pendulum moving.