Gears, Pulleys, and Levers Flashcards

A worm gear system uses a worm with 1 thread meshing with a worm wheel of 40 teeth. What is the gear ratio?

Answer: 1:40

The gear ratio of a worm drive equals the number of teeth on the worm wheel divided by the number of worm threads: 40 ÷ 1 = 40:1 reduction.

In an elevator hoist system, a sheave acts as a:

Answer: Pulley wheel grooved for rope or cable

A sheave is a grooved wheel (pulley) designed to guide and support a rope, cable, or belt in elevator systems.

If a lever arm is 6 feet long and the fulcrum is 1.5 feet from the load end, what is the mechanical advantage?

Answer: 3

MA = effort arm ÷ load arm = 4.5 ÷ 1.5 = 3.

Which type of gear converts rotational motion between shafts that are at right angles to each other?

Answer: Bevel gear

Bevel gears are specifically designed to transmit power between intersecting shafts, typically at 90-degree angles.

A movable pulley attached to the load effectively:

Answer: Halves the required effort

A movable pulley distributes the load across two rope segments, so only half the load force is required as effort.

Helical gears are preferred over spur gears in many applications because they:

Answer: Run more quietly and carry higher loads

Helical gears have angled teeth that engage gradually, resulting in quieter operation and greater load capacity than spur gears.

A third-class lever has the effort applied between the fulcrum and the load. This arrangement always:

Answer: Multiplies distance/speed of movement

Third-class levers sacrifice force (MA < 1) but amplify the distance and speed of the load's movement.