Page:Motors and motor-driving (1902).djvu/252

220 at the greater the frictional grip round to. As soon, however, as the car is reversed or moves backward, so that the drum turns in the opposite direction, the friction of the band upon the drum pulls the band round towards the fixed point and further frictional grip does not take place, as the tendency is to reduce the pull on. If now the band be coupled at



to a lever pivoted at, as in fig. 6, the other end being coupled to the end of the same lever and pulled by the rod  and pedal , the brake will act both ways. If the drum be turned in the backward direction of the arrow, the pull at will not be lost through the effect of the fixity of the point, for both ends



and are pulling on the drum and increasing the pull on increases the frictional hold in a rapid degree.

A good form of brake is that shown by fig. 7, in which the pull on the rod from pedal  pulls the arm, and thereby pushes the links  outwards and forces the blocks  outwards into the brake drum ring , the whole of the brake tackle