Carriage Clock

Overview

A carriage clock is a small spring-driven clock made to be carried, the design that let travellers keep accurate time before wristwatches. The French perfected it in the 19th century as the pendule de voyage: a rectangular gilt-brass case glazed on every side, topped with a folding handle, and fitted with a strike and an alarm so it could double as a bedside clock on the road. Because there is no pendulum, it keeps time in any position and survives being jolted in a coach or a travelling box.

The clock is built around a few groups. The Movement holds the going train and is regulated by a separate platform escapement visible through the glazed top of the Case. A second barrel drives the Strike & Alarm Train train that sounds the hours and the alarm on a coiled gong. The time is read on the Dial & Hands, and both springs are wound and the hands set through the Winding Arbor in the back door.

How it works

In place of a pendulum, the clock uses a platform escapement, a self-contained lever escapement and sprung balance mounted horizontally on its own little plate above the movement. The going barrel's mainspring drives the wheel train up to the platform, where a jewelled pallet fork locks and releases the escape wheel and impulses the balance once per swing. The balance, returned by its hairspring, beats at a fixed rate, and because the whole assembly is horizontal the clock holds that rate whichever way up it is set down or carried.

The strike side runs from its own mainspring barrel. On the hour a lifting lever releases the strike train; an air-brake fly paces it while a notched count wheel meters how many blows the hammer strikes on the coiled gong. The alarm works the same gong: an alarm-set disc on the dial trips the train at the chosen time to sound a run of strokes. A key in the back door winds both barrels and, on a separate arbor, sets the hands and the alarm.