Remonto

Remonto is a term sometimes used in horology to refer to a remontoire, a device designed to deliver a constant amount of energy to a clock or watch escapement. Its purpose is to compensate for the varying torque from the mainspring as it unwinds, which would otherwise cause the movement’s rate to drift.

Most remontoire implementations employ an energy reservoir—often a secondary spring or a small weight—that is recharged at regular intervals by the mainspring but isolated from the main gear train during the store-and-release cycle. The stored energy is then released to the gear train in a controlled, nearly constant quantity, delivering a fixed torque to the escapement and improving timekeeping stability.

Historically, remontoire-based constant-force mechanisms emerged in the 18th and 19th centuries to enhance precision in precision clocks and marine chronometers. In contemporary mechanical watches, true remontoire devices remain rare and are typically found in high-end or specialist pieces where engineers trade added complexity for improved stability. The standard term in most sources remains remontoire, while remonto is sometimes encountered as shorthand or in brand-specific usage.

Related concepts include constant-force mechanisms and remontoire d’égalité, which describe various approaches to delivering a steady driving torque to the escapement. The remontoire idea continues to be discussed in the context of historical clockmaking as well as in modern haute horlogerie experiments with precision engineering.