Longcase Clock Origin
The longcase clock was made possible because of the invention of the anchor escapement mechanism around 1670. Earlier than that, the pendulum clock movements used an older verge escapement mechanism, which required very wide pendulum swing of about 80-100 degrees. With this wide swing, long pendulums are not suitable for long case, so mostly longcase clock has short pendulums. With the anchor mechanism, the pendulum swing was reduced around 4 to 6 degrees, which enables the use of longer pendulums, which had slower beats. It needs less power to keep going, made less friction and wear in the movement, and were more accurate.
Most of the longcase clocks use a second pendulum also known as “Royal” pendulum that each swing takes one second. Its length is about 39 inches long, and requires a long narrow case. The long narrow case actually predated the anchor clock by a few decades, appearing in 1660 to allow a long drop for the powering weights. However, once the second pendulum began to be used, this long weight case shows perfect for homes. Modern longcase clocks use a more precise variation of the anchor escapement called the deadbeat escapement.