Pendulum clocks have been in production -- under more or less the same mechanisms --- since the 17th century. Though composed of several complicated-looking parts, the mechanisms of pendulum or pendulum-derived clocks such as wristwatches are relatively easy to understand and may often be easily fixed once you know the functions of the individual parts.

Basic Parts

On the exterior, these clocks have an hour, minute and sometimes second hands. Pendulum clocks are weight-powered, and that mechanism is found on the interior of the timepieces, along with the weights themselves. In most pendulum clocks, the pendulum swings once per second, while in older grandfather clocks, it may be once per two seconds. So, when you wind the clock, or more accurately, lift the weight, the clock gains "potential energy" in the Earth's gravitational field. The clock then consumes this potential energy as the weight falls and thus drives its mechanism. The only thing that affects the period of the pendulum is its own length. The gears are used to exaggerate the period of time for which the pendulum swings. The clock, therefore, may not need to be wound as often as you would normally expect. Spring-driven clocks such as wristwatches work because a key winds the mechanical main spring that in turn powers the gears as the clock unwinds. Such movements generally drive the movements for about seven days before they eventually unwind, though it is possible to get 14 to even 31- day movement clocks.

Common Problems

Most clocks can be fixed easily, as the few mechanical components means that only so much may go wrong. The following is a list of some of the more common pendulum clock afflictions: Out of Beat If the clock is ticking incorrectly, that is, tock-tick, tock-tick instead of tick-tock, tick-tock, it can often be corrected by placing something, such as a flint, under one side of the clock case to make the tick and the tock evenly spaced. This temporary solution may be further corrected by bending the verge one way or another. The verge is the only movement part that touches the pendulum and drives it back and forth, making the tick-tock sound. Ticking, but Stops Make sure that the hands aren't touching. And is the pendulum touching another object during its swing? The clock may also be off level. There may also be a general lack of power in the time train; meaning it requires a good cleaning and general check, making sure that the gears are oiled properly. No Tick Sound The hands may be touching, or the chiming mechanism may be out of sync. Cleaning. Often clocks just need to be cleaned. This may be done by disassembling it, or not, depending on the severity of the problem.