Figure 1.55 shows a drum brake mechanism. When the crank AB rotates counterclockwise, the brake pads are pressed against the drum. The length AB is 100mm, the length BC is 60mm, then length CD is...

Figure 1.55 shows a drum brake mechanism. When the crank AB rotates counterclockwise, the brake pads are pressed against the drum. The length AB is 100mm, the length BC is 60mm, then length CD is 156mm and the distance between A and D is 110mm. Is the linkage Grashof? Does it matter for this mechanism?

Figure 1.55