Mechanical Systems
Mechanical systems are designed to manipulate motion by adjusting:
- Speed: How fast an object moves.
- Direction: The path an object follows.
- Power: The force applied to move an object.
Gear-Driven Systems
Gear
A toothed wheel that meshes with another to transmit motion or change speed/direction.
- Use interlocking toothed wheels to transfer rotary motion.
- Can change speed, torque, or direction depending on gear size.
- Common in clocks, bicycles, and car transmissions.
Gear Ratios
The gear ratio is the ratio of the number of teeth on two interlocking gears. It determines the relationship between speed and torque.
$$\text{Gear Ratio} = \frac{\text{Number of Teeth on Driven Gear}}{\text{Number of Teeth on Driver Gear}}$$
Belt-Driven Systems
Belt-Driven System
A belt transfers power between at least two pulleys — the driver pulley moves the belt, and the driven pulley is moved by it.
How Belt-Driven Systems Work
- Use belts and pulleys to transfer motion over a distance.
- Often used where smooth, quiet operation is preferred.
- Found in fans, sewing machines, and car engines.
Advantages and Disadvantages
- Advantages:
- Quiet operation
- Flexibility in layout
- Disadvantages:
- Slippage can occur, reducing efficiency
- Belts may wear out over time
Cam Systems
Cam
A mechanical part that converts rotational motion into linear motion.
- Use a rotating cam to convert rotary motion into reciprocating or linear motion.
- Profile shape of cam determines the follower's movement.
- Common in engines, automated toys, and machinery.
How Cam Systems Work
- Speed Adjustment:
- Shape of the cam: Determines the speed and distance of the follower's movement.
- Direction Change:
- Cams can create complex motion patterns, such as oscillation.
- Power Transmission:
- Efficiently convert rotary motion to linear motion.
Lever Systems
Lever
A rigid bar that pivots on a fulcrum to move a load with an applied effort.
- Already covered in 3.3.3, but important to reiterate that levers can change:
- The direction of force
- The magnitude of effort
- Used in tools, lifts, and control systems.
How Lever Systems Work
- Speed Adjustment:
- Longer levers: Increase speed but reduce force.
- Direction Change:
- Levers can change the direction of applied force.
- Power Transmission:
- Efficiently amplify force with minimal input.
Linkage Systems
Linkage
A mechanical system of connected parts that changes the direction or size of a force.
- Use rigid links and pivots to transmit motion in a set path.
- Can convert one type of motion to another (e.g. rotary to linear).
- Often used in folding mechanisms, robotic arms, bicycle brakes.
How Linkage Systems Work
- Speed Adjustment:
- Linkages can modify the speed and range of motion.
- Direction Change:
- Complex linkages can create intricate motion patterns.
- Power Transmission:
- Efficiently transfer force across multiple points.
Types of Linkages
Reverse Linkage
A linkage that reverses the direction of a force or motion.
Push-Pull Linkage
A linkage system that allows force to be transferred in both directions — when pushed or pulled.
Parallel Linkage
A linkage system where a central point is constrained to move in a nearly straight line.
Bell Crank Linkage
A linkage that converts vertical motion into horizontal motion, or the other way around.
