Escapement mechanism for pendulum clock - has helical spring around balance beam in cylindrical housing held by pressure near friction disc

摘要

The escapement mechanism has an anchor (1) mounted so that it can rotate on a balance beam (9). The anchor is connected to the axis by a friction coupling having a pressure spring acting in an axial direction and two friction discs (12,15) supported by the exterior surfaces of the anchor. The pressure spring is a helical spring (16) straightened at either end and having a maximum of five complete spirals, the distance between the spirals (s) being 1.3 to 1.5 times the thickness (d) of the wire. The spring surrounds the balance beam axis concentrically, with little radial play, and is housed in a cylindrical recess (18) of a support case (17) held by pressure on the balance beam axis a short distance from one of the friction discs (15). The internal dimensions of the cylindrical recess are such that the wall enclosing the pressure spring allows little radial play.