What is the name of the enchanted mantel clock in the castle?

The enchanted mantel clock in the castle is named Cogsworth.

Cogsworth is the Beast’s majordomo and head butler, transformed into a mantel clock by the enchantress’s spell. His name combines “cog,” a gear inside a clock, with “-sworth,” a traditional personal-name ending, making it a fitting pun for a time-conscious household servant.

In the 1991 film, David Ogden Stiers voiced Cogsworth and also narrated the opening prologue. Cogsworth is highly loyal to the Beast and generally tries to enforce his master’s rules, although his caution often puts him at odds with Lumiere, the rebellious enchanted candelabra. Their arguments provide much of the castle’s comic energy.

The household objects are easy to mix up because they appear together in the same scenes. Cogsworth is the clock, Lumiere is the candelabra, Mrs. Potts is the teapot, and Chip is the teacup. Cogsworth’s transformation ends when Belle’s love breaks the curse and restores the castle’s servants to human form.