1. Mechanisms from Simple Machines
Principles of EngineeringTM
Unit 4 – Lesson Mechanisms
Forging new generations of engineers
Project Lead The Way, Inc.
Copyright 2007

2. Mechanisms
From Simple Machines

3. UNIVERSAL JOINT
Transmits power when two shafts are not in line.

4. Two spur gears reduce speed, increase torque and change the rotational direction of the shafts.

5. The addition of a third gear, the middle idler gear, has no effect on speed and torque, but input and output shafts turn in the same direction.

6. RACK & PINION
Rack (in red) & pinion (in black) converts rotary motion of the pinion gear to linear motion of the rack. It is a reversible, positive drive with no slipping.

7. CROWN & PINION
Crown & pinion gears reduce speed and increase torque. The output shaft is at a 90-degree angle to the input shaft. The gears rotate in opposite directions.

8. BEVEL GEARS
Bevel gears increase torque or speed. The output shaft is at a 90-degree angle to the input shaft. The gears rotate in opposite directions.

9. WORM GEAR
The worm gear increases torque and reduces speed. The output shaft is at a 90-degree angle to the input shaft. Direction of rotation can be reversed, but the output gear cannot drive the worm gear.

10. CAM
As a cam rotates the flat follower is raised and lowered, converting rotary motion to linear motion.
FOLLOWER
CAM LOBE

11. CHAIN & SPROCKET
Chain and sprocket apparatus increases speed or torque and can run in reverse direction with no slipping. Input and output shafts rotate in the same direction.

12. PULLEY & BELT
A pulley and belt drive can increase torque or speed and can run in reverse. Input and output shafts are parallel and rotate in the same direction. Slipping of the belt may occur.

13. MOTOR DRIVEN WORM
A motor driven worm reduces speed and increases torque. The output shaft is at a 90-degree angle to the input shaft. Direction of motion is reversible, but the output gear cannot turn the worm gear.

14. MOTOR DRIVEN PULLEY & BELT
A motor driven pulley and belt drive can increase torque or speed. Input and output shafts are parallel and rotate in the same direction. Slipping of the belt may occur.

15. CRANK THROW & SLIDER
A crank throw and slider converts rotary motion to linear motion. Direction of rotation is reversible. Input and output shafts are at 90-degrees.

16. WHEEL & SLIDER
A wheel and slider converts rotary motion of the wheel to linear motion of the slider. Direction of rotation can be reversed. Input and output shafts are at 90-degrees.

17. SCREW & LEVER
A screw and lever converts rotary motion to linear motion and increases torque. Direction of rotation is reversible.