Page:Motors and motor-driving (1902).djvu/251

Rh brakes are of the utmost importance. So long as the axles do not break and the steering gear steers, an expert driver can rub along with very poor brakes until familiarity with risks and dangers leads him into a smash, or until some very near squeak makes him shudder when he thinks about it after he is in bed and the light out; and then he looks to it on the morrow. Of these incidents we do not hear much, but we all know of the smashes and the fatal accidents that have happened to those on runaway or brake-given-way cars, and Mr. Hutton's narrow escape at the end of an unwonted rush downhill into Grantham, and Mr. Graham White's run-away at Dover, are instances of the more obvious kind of evidence of the necessity for good brakes. For the beginner there is no working part of a car so necessary to his safety as the brakes. He finds that stopping is very frequently more important than going if he values either his life or that of others, or wants to save his car and is not anxious to pay for smashing carriages or horses. Even the makers of the lighter French vehicles no longer fit their cars with brakes not big enough for a bicycle or good enough for a horse-rake.

Many brakes have in the past been generally made or fitted so that they will only hold a little in any direction, some that would only hold well in one direction, and some that held too well, came into action too severely, in one direction, namely forward, and very few that held well in the backward direction. A great deal of attention has lately been paid to this question, with the result that brakes long well known to mechanical engineers have been applied to motor vehicles.

A common form of brake that will hold only in one direction is shown in diagram fig. 5. In this a brake drum is surrounded by a brake band, fastened at one end to a fixed stud at , and pulled at the other end  by a rod , connected to a pedal. This brake acts perfectly so long as the drum rotates in the direction shown by the arrow, because the friction of the band on the drum from near  to  pulls on the band in the same direction as the pedal, and thus the greater the pull