Page 158 - Tribology in Machine Design

144 Tribology in machine design

Expanding sin(/? — 0) and integrating, this equation becomes

and proceeding as follows

Substituting the numerical values

For the radius of the friction circle

Alternatively,

In Fig. 4.44, R^ =Rsec</> is the resultant force opposing the motion of the
drum. R\, equal and opposite to R l f is the resultant force on the shoe. The
reaction Q at the hinge passes through the point of intersection of the lines
of action of R\ and F. As the direction of Q is known, the triangle offerees
representing the equilibrium of the shoe can now be drawn. The results are
as follows:
(a) clockwise rotation, F=1507N;
(b) anticlockwise rotation, F = 2710N.

4.11.3. The band and block brake
Figure 4.45 shows a type of brake incorporating the features of both the
simple band brake and the curved block. Here, the band is lined with a