Angular Pendulum

From The American Horologist magazine, January 1942

Angular Pendulum

By W. H. SAMELIUS, Director Elgin Watchmaqers College

This type of pendulum is formed of two pieces, or legs, like a sector, and suspended by the angular point "A". This pendulum is constructed with a view of diminishing the length of the common pendulum, and at the same time maintain, or even increase the time of vibration. In this pendulum the time of vibration depends on the length of the legs and on the angle contained between conjointly, the duration of the time of vibration increasing with the angle.  Consequently, a pendulum of this construction may be made to oscillate in any given time.

At the lower extremity of each leg is a ball or the usual bob, and if it vibrates half-seconds when the legs are closed, it will vibrate full seconds when the legs are opened, so as to contain an angle equal to 1510 2' 30".

This pendulum is used on occasions when it is desirable to have a pendulum vibrate long portions of time and when the situation will not admit of a pendulum of the usual construction, but it is not suited for any purpose where accuracy is required.

The difficulty of compensating this pendulum and the great and fatal tendency it has to wobble, or swing in an elliptical plane, renders it unsuitable for purposes where precision is an object.