Gears, Pulleys, and Levers Flashcards

What is 'backlash' in a gear system?

Answer: The small gap between meshing gear teeth

Backlash is the slight clearance between mating gear teeth, necessary for lubrication and thermal expansion but too much causes imprecision.

A compound lever system uses two levers in series. If each lever has a mechanical advantage of 4, the total mechanical advantage is:

Answer: 16

In a compound lever system, the total mechanical advantage equals the product of each individual lever's MA: 4 × 4 = 16.

A traction elevator uses rope friction over the drive sheave rather than a drum winder. The primary advantage is:

Answer: Allowing unlimited travel height without rope length limits

Traction systems are not limited by rope wound on a drum, enabling skyscraper heights that drum systems cannot achieve.

Gear pitch (diametral pitch) refers to:

Answer: The number of teeth per inch of pitch diameter

Diametral pitch is the number of gear teeth per inch of pitch diameter and determines whether two gears can mesh together.

If the effort arm of a lever is 3 feet and the load arm is 1 foot, and you apply 40 lb of effort, what load is lifted?

Answer: 120 lb

MA = effort arm ÷ load arm = 3 ÷ 1 = 3; Load = 40 × 3 = 120 lb.

In a V-belt and pulley system, if the drive pulley has a 4-inch diameter and the driven pulley has a 12-inch diameter, the speed ratio is:

Answer: 1:3 (driven is slower)

The driven pulley is 3× larger, so it rotates at 1/3 the speed of the drive pulley — a 1:3 speed ratio.

When a pulley system is said to be '100% efficient,' it means:

Answer: No energy is lost to friction

A 100% efficient pulley system would have zero friction losses, meaning all input work is transferred to the load — an ideal, theoretical condition.