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The Construction of the Clock In structural terms the Winter Palace tower clock belongs to the commonest sort of timepiece with quarter chimes. It consists of three main sections: the clock movement, the quarter-chime mechanism and the hour-strike mechanism. Each of them has its own driving weights. The clock movement or "going train" sets the chiming train in motion every quarter of an hour, and that unit in turn triggers the striking train at the end of each hour. The quarters are chimed on the two smaller bells, while the hours are struck on the largest bell. The bells are located on the roof of the building, directly above the clock, behind the peak of the pediment. (Interestingly, the sound of the bells is reflected back by the pediment and heard far better in the courtyard of the Hermitage than in noisy Palace Square.) The clock movement belongs to what is known as the "flatbed" type: the frame of the mechanism has an upper surface to which all the trains of the clock are attached independently. (The same method was used in the Great Clock (inaccurately known as Big Ben) installed at the Houses of Parliament in London in 1859. This approach makes it possible to remove and replace each element of the mechanism separately. It is undoubtedly more convenient in terms of manufacture, assembling and servicing. However, since all the axes lie in a single plane, the frame becomes considerably longer than in tower clocks of more traditional types. Realizing that the frame would not fit in the space allotted to it, Helfer divided it into three parts, corresponding to the three trains, and arranged them in a "Ï" form. The clock acquired a highly unusual appearance: the going and chiming trains were placed side by side, while the striking mechanism was placed at the right angle to them. Helfer had to do without the cast-iron frame that was normally used in a flatbed construction (and that usually bears the maker’s name). He assembled a flat frame of steel beams of square cross-section, placing them on short legs. He also had to rethink the release levers. The result was a compact construction (118 x 90 x 60 cm), almost square when viewed from above, that fits well into the small (2.5 x 2.5 m) room beneath the roof of the palace. The relatively small size of the weight drum (25 cm long), one rotation of which corresponds to one full sweep of the minute hand, meant that the clock had to be wound once a day. The upper part (on turning brackets) of a pulley system has survived that was used to compensate for the inadequate depth of the weight shaft. To make winding easier the clock mechanism was raised on a block of wood so that the handle was at chest height. The Amant escapement used in the clock provides a heightened degree of precision and is typical for continental tower clocks. The pendulum has a design period of 0.938 seconds and a length of 93.24 cm. In Soviet times an unsuccessful attempt was made to install an electrical system to wind the clock.
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 Pendulum Larger image |
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