What does the acronym "S-cam" stand for in air brake systems?

The acronym "S-cam" is derived from its design characteristics within air brake systems, specifically referring to a particular type of brake shoe mechanism. In air brake systems, the S-cam acts as a key component that transforms the rotational motion of the brake drum into the linear motion that engages the brake shoes. The S-cam is shaped like the letter "S," which allows the shoes to spread apart and press against the brake drum effectively when activated through air pressure. This design is crucial for ensuring that brakes apply properly and safely in large vehicles. Understanding the function and mechanics of the S-cam is essential for any driver operating vehicles with air brake systems, as it plays a vital role in the overall braking performance.