Historical Development of the Windmill - Wind Turbine Technology: Fundamental Concepts of Wind Turbine Engineering - page 19

Figure 1-9. The drive train of a typical post mill.
As illustrated in Figure 1-10, the brake is simply a friction band around the circum-
ference of the brake wheel, made of a number of curved wooden brake blocks banded
together, with one end of the band anchored to a timber of the buck, and the other to a
brake lever , itself pivoted at a ixed point on the structure. The active end of the brake
lever could be pulled up or down by a rope. The brake lever had an iron pin that could
engage with a notch in a catch plate , free to swing from a pin in its head. The brake lever
was very heavy, and when it was unsupported by the rope or the catch plate, it pulled the
brake blocks suficiently hard against the rim of the brake wheel to hold the windshaft at
Figure 1-10. Diagram of a post-mill break.