Tasapainojousen

Tasapainojousen, a Finnish term, translates directly to "balance spring" or "hairspring" in English. It refers to a very fine, coiled spring found in mechanical watches and clocks. Its primary function is to regulate the oscillation of the balance wheel, which in turn controls the speed at which the timekeeping mechanism operates.

The balance spring is typically made from a non-magnetic alloy that possesses excellent elasticity and resistance to temperature changes. Its design is crucial for accurate timekeeping. The spring's rate, or how quickly it expands and contracts, must be precisely calibrated. This calibration is achieved through a process called "poising" the balance wheel and adjusting the effective length of the spring.

The interaction between the balance spring and the balance wheel forms an oscillator. Each swing of the balance wheel, controlled by the spring, corresponds to a specific unit of time. The escapement mechanism then translates these oscillations into the movement of the hands on the watch or clock face. Without a properly functioning tasapainojousen, a mechanical timepiece would not be able to keep accurate time. Its miniaturization and precision manufacturing are testaments to the ingenuity of watchmaking.