BRAKE EFFICIENCY

Manawatu Times, Issue 6848, 1 March 1929, Page 4

BRAKE EFFICIENCY

STEADY IMPROVEMENT. Each year the average speed of traffic increases as does the average speed of tho car, and also the volume of cars on the congested road. Brakes must improve equally as rapidly as the speed of the car; moro rapidly, in fact, for brakes have been a long way behind speed for years past, and it is only since the relatively recent arrival of four-wheel brakes that general safoty has been at all assured. Progress has been made with brake systems, and, indeed, is being made quite rapidly by those manufacturers of cars who are keen enough to study the performance of efficient contemporaries. A year or two ago, cars with four-wheel brakes took 90ft. to 110 ft. to pull up in emergency from 40 m.p.h. To-day the brake system urgently needs attention if the vehicle cannot make an emergency stop from that speed of 60ft. or 70ft. and stop smoothly at that.

Attention of efficiency in the mechanism has obtained these results. Mon and women are capable of exerting a certain average pressure with a single foot, and there is a limit of only a few inches of travel over which this pressure can comfortably be maintained. These two factors provide nil the leverage for brake application that is available. If the system of lovorages and tio-rods leading to the brake shoes is efficiently designed, and made, then tbis available force is quite sufficient to give adequate control for a car up to 20 h.p. and capable of 60 m.p.h. Larger cars of greater weight and speed need some form of mechanical assistance, or servo system, in order to relieve the driver of hard work. Servo motor brakes of tho vacuum operating type, such as the Dewandro and tho Westinghouse, aro ceasing to find place on the small and medium-sized car because detail improvement in actuating gear 'is making them less necessary, and’ partly because of price, but on larger cars, in which expense is more or less, a secondary consideration, such systems are falling into regular use, to say nothing of the mechanical type of servo brake and the hydraulically assisted brake.