Clocks

Origin of the term “Grandfather Clock”

Grandfather Clocks were not always known as Grandfather clocks!

The Oxford English Dictionary states that the popular 1876 song “My Grandfather’s Clock” is thought to be responsible for the common name “grandfather clock” being applied to the “longcase clock.”  grandfather clock

The song was composed an American songwriter by the name of Henry Clay Work who discovered a long grandfather clock in The George Hotel in Yorkshire, England.

When he enquired about the clock, he was informed that it had only two owners.

After the first owner died the clock became inaccurate and when the second owner died, the clock stopped working completely!

The story inspired Henry to create the song.

Grandfather Clock | Long Case Clock

grandfather clockA longcase clock, also tall-case clock, floor clock, or grandfather clock, is a tall, freestanding, weight-driven pendulum clock with the pendulum held inside the tower or waist of the case.

Clocks of this style are commonly 6–8 feet tall.

The case often features elaborately carved ornamentation on the hood (or bonnet), which surrounds and frames the dial, or clock face.

The English clockmaker William Clement is credited with the development of this form in 1670. Until the early 20th century, pendulum clocks were the world’s most accurate timekeeping technology, and longcase clocks, due to their superior accuracy, served as time standards for households and businesses.

Today they are kept mainly for their decorative and antique value.

Development of the Grandfather Clock

The advent of the longcase clock is due to the invention of the anchor escapement mechanism by Robert Hooke around 1658. Prior to that, pendulum clock movements used an older verge escapement mechanism, which required very wide pendulum swings of about 80-100°. Long pendulums with such wide swings could not be fitted within a case, grandfather clockso most freestanding clocks had short pendulums.

The anchor mechanism reduced the pendulum’s swing to around 4° to 6°, allowing clock makers to use longer pendulums, which had slower “beats”. These consumed less power allowing clocks to run longer between windings, caused less friction and wear in the movement, and were more accurate.  Almost all long case clocks use a seconds pendulum (also called a “Royal” pendulum) meaning that each swing (or half-period) takes one second. These are about a metre (39 inches) long (to the center of the bob), requiring a long narrow case.

The long narrow case actually predated the anchor clock by a few decades, appearing in clocks in 1660 to allow a long drop for the powering weights. However, once the seconds pendulum began to be used, this long weight case proved perfect to house it as well.

British clock maker William Clement, who disputed credit for the anchor escapement with Robert Hooke, produced the first long case clocks around 1680. Within the year Thomas Tompion, the most prominent British clock maker, was making them too.

Modern long case clocks use a more accurate variation of the anchor escapement called the deadbeat escapement.

Most of a long case clock’s height is used to hold the long pendulum and weights. The two chains attached to the weights and the lack of winding holes in the dial show this to be a 30-hour clock.

8 Day and 30 Hour Grandfather Clocks

Traditionally, long case clocks were made with two types of movement: eight-day and one-day (30-hour) movements. A clock with an eight-day movement required winding only once a week, while generally less expensive 30-hour clocks had to be wound every day.

Eight-day clocks are often driven by two weights – one driving the pendulum and the other the striking mechanism, which usually consisted of a bell or chimes. Such movements usually have two keyholes, one on each side of the dial to wind each one. By contrast, 30-hour clocks often had a single weight to drive both the timekeeping and striking mechanisms.

Some 30-hour clocks were made with false keyholes, for customers who wished that guests to their home would think that the household was able to afford the more expensive eight-day clock.

All modern striking longcase clocks have eight-day movements. Most longcase clocks are cable-driven, meaning that the weights are suspended by cables. If the cable were attached directly to the weight, the load would cause rotation and untwist the cable strands, so the cable wraps around a pulley mounted to the top of each weight.

The mechanical advantage of this arrangement also doubles the running time allowed by a given weight drop.

Cable clocks are wound by inserting a special crank (called a “key”) into holes in the clock’s face and turning it. Others, however, are chain-driven, meaning that the weights are suspended by chains that wrap around gears in the clock’s mechanism, with the other end of the chain hanging down next to the weight. To wind a chain-driven longcase clock, one pulls on the end of each chain, lifting the weights until the weights come up to just under the clock’s face.