Anniversary Clock

An anniversary clock is a clock driven by a spring fitted with a pendulum. These clocks are elaborately designed and made of crystal and brass. These are usually presented as gifts for weddings and other special occasions.

Historical Background

The term was coined by the clocking firm Bowler & Burdock Company in 1901. The name was given to the 400 Day Clock, renowned for its torsion pendulum. The clock was invented by the American Aaron Crane back in 1841.

What made this clock significant was that it was the first that didn’t require daily winding. The pendulum itself needed winding only once a year. Eventually, it became fashionable for couples to wind the clock on their anniversary. This helped the watch become a popular wedding present.

Appearance

The clocks are recognizable by their crystal or glass case. This transparent material allows you to see the interior mechanisms of the unit. Aside from the pendulum, there are four brass balls that move below the clock face.

Some models also have brass handles at the top part. As they are often used as wedding gifts, the couple’s wedding date can be etched on the clock.

Many models also have dangling chimes projecting from the display. These will turn while the unit is running. All of these units display the numbers in Roman numerals. On antique models, the Roman numeral IV is displayed as IIII.

How the Unit Works

The unit functions as a mechanical clock fitted with the wound pendulum. Rather than swing right to left, the pendulum has a clockwise and counterclockwise motion.

The anniversary clock has a weighted disk hanging by the torsion spring. The twisting of the spring is what gives the gear power. The clock can last 400 days with only one winding. In terms of design, the unit is similar to a hairspring or watch’s balance wheel.

The Timekeeping

The timekeeping runs via the internal gears of the unit. The internal gears power the torsion spring. In terms of energy usage it is much more efficient than the typical pendulum.

During the early days accurate timekeeping was a problem due to humidity. However in 1951, Charles Terwilliger started using a different spring that resulted in more precise timekeeping.

Maintenance

The older models must be handled with care as they are sensitive to temperature changes and rough handling. Some of the newer models are more robust and tell time accurately.

It is essential the clock be placed on an even surface. Otherwise, the clock will not run. Any sort of imbalance will force the pendulum to cease twirling. There are three discs at the clock base. You can adjust these until the right balance is attained.

Majority of the clocks have removable glass encasings. You can take it off to clean the inner parts of the clock.

With its striking appearance and unique features, the anniversary clock makes for a truly wonderful present. Made of glass, brass and laden with other decorative elements, it is a gift couples will appreciate.