The chronograph mechanism is a collection of parts which are compiled together to provide additional functionality within a timepiece.
In most cases, you will find that this compilation of parts will be so closely integrated with the base movement that the two become one whole, and thus we would normally simply describe this whole as a Chronograph Movement.
The reason I make this distinction is because you may, on occasion, come across the Chronograph Module.
The Chronograph Module could be considered a completely separate entity from the base movement and can be detached as a whole when servicing.
The most notable Chronograph Module mechanisms commonly found in recent years are developed by the Swiss manufacturer, Dubois Depraz and you may find these modules attached to slightly modified ETA calibre’s such as the 2892-A2 or 2824
But in this chapter of the course we are going to cover the most common chronograph types as found in modern and vintage Chronograph Movements and these are mechanisms using either of two methods…
- The Pillar Wheel Method
- The Cam Method
And these are two methods adopted by movement manufacturers to basically achieve the same result.
And on that note, most chronograph mechanisms will have several things in common and will need to meet the following criteria…
- There needs to be an interface so that the chronograph can be driven at the same rate as the regular train of wheels.
- There needs to be a facility for the user to engage, disengage and reset the chronograph.
- A chronograph needs to provide an indication of the time elapsed from when the mechanism is engaged until it is disengaged.
And so, let’s discuss how these requirements are usually achieved, and we shall start by taking a look at how the chronograph mechanism is driven.