Pendulum clocks

 

Constructor – Sigmund Riefler

Manufacturer:                                             Clemens Riefler

Year of production:                                                      1905

Serial number:                                                        No. 116

Pendulum:                          Thermally compensated , T = 2 s

The clock was installed on June 21, 1905, and was driven by electric battery (6V).

 

 

 Constructor – Ludwig Strasser

Manufacturer:                                       Strasser & Rhode

Year of production:                                                   1925

Serial number:                                                     No. 969

Pendulum:                        Thermally compensated, T = 2 s

The clock was set to operation on August 14, 1925. It is rewound manually - which enables the clock to operate for a week. The mechanism for two electrical output signals was built by watchmaker J. Schnittlinger.

Both clocks have two electrical output signals:

-         Second pulse for external clocks synchronization (Siemens I and II),

-         Minute pulse for marking the end of a minute on  Wiechert seismographs.

The clocks were installed in double cabinets to avoid influence of daily temperature variations on clock’s drift.

The clocks were operational at Grič until October 17, 1984. The watchmaker Ivan Geresdorfer thoroughly cleaned, repaired and reinstalled the clocks, so that they were operating again from December 11, 1984 until February 4, 1992. Up to the end of the homeland war (1991-1995) these clocks, with all the necessary equipment, were able to transmit time-signals within hours, if needed.

 

Pendulum clocks S1 i S2

 

Manufacturer                                                     Siemens

Year of production :                                                 1928.

Pendulum:                        Thermally compensated, T = 2 s

 

The clocks were, as a city time-reference centre, set to operation in March 1929. They could be rewound manually or electrically. The pendulum was synchronised with the Riefler clock. These clocks were, for some time, used to control the public clocks in Zagreb. The mechanism with electrical contacts gives the well-known time-signal for the Zagreb radio-station. Graphical presentation of the full-hour time-signal in the period 1926-1993:

 

 

                   The end of the third audio-signal indicates the end of the hour

 

The clocks were operational at Grič until October 17, 1984. The watchmaker Ivan Geresdorfer thoroughly cleaned, repaired and reinstalled the clocks, so that they were operating again from December 11, 1984 until 1996. Up to the end of the homeland war (1991-1995) these clocks, with all the necessary equipment, were able to transmit time-signals within hours, if needed.