BRAKE action extends from the foot-pedal through various connections and devices to the point of contact of the braked wheel on the ground but, although brake-development work has been extensive for that portion of the brake mechanism which extends from the foot-pedal up to the point of application of brake pressure, the author says that beyond this point practically no improvement has been made. He says further that a study of brakes and the retarding forces they exert on the road surface reveals the primary cause of brake troubles, and then analyzes the design of an efficient braking-system for automobiles, first outlining the ideally perfect mechanism without regard to mechanical limitations.
According to the author, pressure equalization of brakes does not produce equalization of the braking action on the road unless the brake friction and the tire friction are the same for all four wheels; moreover, to produce positive equalization of brake force, it must be accomplished through the brake anchorages, because the forces which they resist are always proportional to the force exerted by the tires on the road. To balance this wheel-pull on the road, the right and the left brake-anchorages must be interconnected so that one brake-force reacts against the other because, in this way, any unbalanced force will produce movement and this movement can be utilized to decrease the pressure of the stronger brake while increasing that of the weaker one until the unbalanced force is eliminated and the movement stops.
Means of accomplishing torque equalization are then illustrated and described, and the results of tests of torque-equalizing mechanisms of various designs are presented, together with accompanying charts. In conclusion, it is said that considerable study has been devoted in the last year to the subject of airplane brakes, and that a modified type of torque-equalized brake has been developed for use on heavier-than-air craft which gives positive control of brake power as well as brake equalization.