This is one of the inspirations for inventing timekeeping devices. Long ago, when electricity is scarce, those who do not have a watch with a repeater complication will find it very difficult to tell time. The repeater complication plays a sound in an audible format upon the demand of its user. There are different types of repeaters nowadays. There are even latest versions that are found to be more accurate. There is a quarter repeater that is more accurate to the quarter hour. There is also a minute repeater that is accurate to the minute.
There are four mechanical systems that go together to establish a quality repeater. These are the winding works, the gear train and escapement, the racks and snails, and the hammers and gongs.
There is an activation button on the edge of the watch case for the repeater to function. There is a side on its edge that has two distinct reasons. First and foremost, it is the on and off button for the repeater mechanism. It also serves as the main source of power for the watch’s entire power movement. Aside from the mainspring it drives, there is s a tiny mainspring that is being driven. For the repeater to run, it needs a significant amount of torque. A substantial amount of torque helps in maintaining the balance that is needed to achieve accuracy. Sometimes the primary mainspring can cause a drop in amplitude in the balance.
Similar to the watch’s main movement, there is a separate gear train and escapement that the repeater needs so that the power from the mainspring will be transmitted to the entire mechanism. The escapement of the repeater is uniquely quiet which is intentionally done so that the sound when the gongs are strike will not be disturbed. A centrifugal governor is used to achieve this. The spinning of the governor is similar to how the ice skater spins. The wider the arms of the ice skater spread, the spin gets slower. There are two arms on the pivots of the governor having weights on the bottom. The rate of the spin equalizes as the arms spread more. This will serve as the escapement. For this to happen, the rate of the turn of the gear train should be relatively high.
To guarantee the right amount of hammer that strikes for hours, quarters, and minutes, there is a number of snails that is attached to the motion works. The cams shape of the snails is especially made with steps. There are 12 steps in the hour snail, there are 4 in the quarter snail, and there are 14 in the minute snail. The steps play vital roles to control the rack movement to stay in the right position. When the gear train starts running, the rack is activated and it moves then touching the appropriate snail.
The sound it makes is the result of the hammers striking the gongs. The teeth of the racks go with the maximum level of the striking of the hammer. When the teeth pass, they trip the hammers leading them to hit the gongs. These gongs come in different lengths. Each length produces different tones. Gongs are made of thin steel wires that are circle-shaped. It is intended to be in a circle shape to encompass the movement.
Featured Image Credit: Youtube – Fman Matahari