Double-toggle Blake crushers In this model (Figure 6.4), the oscillating movement of the swinging jaw is effected by vertical movement of the pitman. This moves up and down under the influence of the eccentric. The back toggle plate causes the pitman to move sideways as it is pushed upward. This motion is transferred to the front toggle plate and this in turn causes the swing jaw to close on the fixed jaw. Similarly, downward move- ment of the pitman allows the swing jaw to open.