Swiss railway clock

The Swiss railway clock was designed in 1944 by Swiss engineer and designer Hans Hilfiker for the Swiss Federal Railways ( SBB). It is characterized by a very clear, reduced design with black scale markings on a white ground and bar-shaped, black hour and minute hands. Digits are missing. This easy to read even from long distances layout became an international model for station clocks.

Later Hilfiker added in cooperation with the manufacturer Mobatime the clock around a red seconds hand in a reminiscent of a conductor trowel form of thin rod and round disc. Technically, it is a Minutensprunguhr with creeping seconds. The second hand is moving a little too fast, so that he stops at each full minute to wait for the minute signal. This pointer " brings calm to the last minute and facilitates the timely Zugsabfertigung. " ( Hilfiker ) Also, this supplement has been adopted by other railway companies.

Break of the second hand of the Swiss railway clock

The unusual break of the second hand had technical reasons. The cost of one of the master clock to the slave clocks in addition to conducting second pulse should be avoided. In addition, the frequent jumping out of a second hand of such size would have affected the life of the clock. Therefore, a local with AC -powered, continuously rotating synchronous motor was chosen for its drive. In order to meet frequency fluctuations, the drive is so designed that the pointer to complete a full revolution with guaranteed minimum wetting rate of about 48.5 Hertz. The start of its next turn is done with the minute pulse, " the top, he will be arrived halted until the following minute pulse, the forward throwing the large hand, simultaneously releasing it for his next turn again. " ( Hilfiker ) This relatively large break ( almost two seconds at rated frequency) could be reduced in the meantime achieved high accuracy of 50 -hertz alternating current network, but has not been changed at the Swiss railway station clocks to this day.

Stopping the second hand is possible by turning off the synchronous motor. But the producer Mobatime chose from the beginning ( 1947), a mechanical solution. In the groove on the periphery of a disk, a pin snaps, which is briefly pulled from the magnet, which moves the minute hand every minute. The latching ensures that the second hand gets a safe rest position. The synchronous motor rotates continuously. During the second stop, he slips into a friction clutch located in the drive train.

Awareness of design

The design was for watches of Swiss watch company Mondaine Watch Ltd.. taken in consultation with the SBB and manufactured since 1986 in Switzerland. Mondaine watches this type may be described as official Swiss railway clock for the wrist. There is this clock both as usual Quartz Wrist Watch, as well as a clock with stop seconds and minutes go. Drive is also a crystal - controlled stepper motor of about 3 hertz to simulate the steady rotation of the second hand of the original approximately at the latter.

The motif of the Swiss Bahnhofuhr was mapped to the 85- centime stamp the stamp series " design classics Switzerland".

The company Apple uses since September 2012 as the time display on the Apple iPad, the Swiss railway clock. An agreement with the Swiss Railways, for the design of this clock is being protected was, only later. In October 2012, a license fee according to the Tages-Anzeiger, relying on various sources, apparently about 20 million Swiss francs was agreed (about 16.5 million euros ).

Trivia

The fake unrealistic break through the stop of the second hand was made ​​necessary by the applied design principle.

The poet Thomas Mann chose a few years before the construction of the Swiss Railway Watch the metaphor of the short second hand arrest as a sign that a preliminary goal was achieved.

"He could sit, his clock in hand, [ ... ] and look down on their [ ... ] porcelain circular area on the [ ... ] the thin seconds hand did the busy pecking passage of his little sphere. Attention to [ ... ] The Weiserchen tippelte his way without the digits that it reached, touched, crossed, left behind left behind far, came back on and reached again. It was insensitive targets, sections markings. It would have to pause for a moment, or at least 60 else to give a tiny sign that something was accomplished. "