Which term describes the engagement between belt teeth and pulley that prevents slipping?

• A. Slippage
• B. Loose fit
• C. Worn belt
• D. Positive engagement

Answer: (D)

Positive engagement describes the interaction where belt teeth mesh with matching pulley teeth, creating a mechanical interlock that transmits motion without relying on friction. This interlocking keeps the belt from slipping and maintains synchronized speed, which is essential for timing and precise motion. Synchronous or timing belts use this tooth-to-tooth engagement to handle higher loads without slip. If there’s no positive engagement, slip can occur, which is why a plain belt on a smooth pulley or a worn belt can lead to loss of synchronization. So the term that captures the engagement that prevents slipping is positive engagement.