Machinery and Equipment Essentials

Posted on Nov 16, 2024 in Technology

Machinery and Equipment

We live surrounded by machines and equipment: vehicles, watches, televisions, computers, washing machines, mobile phones, etc. From simple tools, like an opener, to more complex systems, like an industrial robot. Machines can be recognized by traits that distinguish them:

  • Work with energy input: Machines and equipment require power supplies to function, either by connecting to a power source, battery, burning fuel, using air-operated pressure, or muscular effort.
  • Transmit and transform energy: The mechanisms and circuits inside machines transmit or transform energy to achieve the desired performance.
  • Produce effects: Machinery and appliances are recognized by the effects of their operation: move, warm, output images, sounds, warp materials, edit or save data, lift weights, etc. Many machines produce multiple effects simultaneously, for example, a washer wets, moves clothes, heats water, and centrifuges.

Machines can be grouped by their impact:

  • Transportation: Many machines enable the movement of people, materials, and products, such as vehicles, boats, trains, bicycles, aircraft, etc.
  • Mechanical work: Machines that change materials and products, such as cranes, drills, industrial robots, sewing machines, or mixers.
  • Temperature and environment: Stoves, lamps, fans, refrigerators, ovens, or incubators modify environmental conditions.
  • Information, sound, and image: Devices for communication, information processing, or recording and broadcasting audiovisual content, such as telephones, computers, cameras, televisions, etc.

Parts of a Machine

Machines consist of many parts with different purposes. Generally, we can distinguish several parts:

  • Structure: The fixed parts that support other components. It can be a framework of bars or an outer casing.
  • Mechanisms: Moving parts like gears, levers, pulleys, and sheaves. They transmit force and movement, often initiated by engines.
  • Circuits: Control the flow of electrical power or pressurized fluid.
    • Electrical circuits include cables, switches, transformers, resistors, or electric motors.
    • Electronic circuits consist of printed circuit boards with resistors, capacitors, transistors, and integrated circuits.
    • Fluid circuits feature pipes and control valves.

Power for Machinery

Machinery and appliances operate from power supplies. The forms of energy currently used are:

  • Electricity: Obtained through mains, batteries, or photovoltaic cells. It produces heat, movement, light, sounds, or images.
  • Thermochemistry: Thermal energy from burning fuel, used in boilers, stoves, motor vehicles, boats, aircraft, and agricultural machinery.
  • Pneumatic pressure: Compressed air or pressurized fluid drives machines like presses, punches, or staplers. Also used in lifting machinery.
  • Mechanics: Forces from muscles power tools, bicycles, tricycles, etc. Mechanical energy from springs is used in toys and watches.

Many appliances and machines are run by motors, which convert energy into mechanical motion.

Engine Types

  • Electric motors: Draw power from electrical current (DC or AC).
  • Combustion engines: Harness energy from fuels. External combustion engines burn fuel outside the machine. Internal combustion engines burn fuel inside a chamber.
Four-Stroke Engine

Used in most vehicles and boats, it consists of a block with multiple cylinders. A piston moves by a crank, turning the crankshaft.

Performance of Four-Stroke Engine

  1. Admission: Piston moves down, air and gasoline enter.
  2. Compression: Valves close, piston rises, compresses mixture.
  3. Bang: Spark plug ignites mixture, piston moves down.
  4. Escape: Piston pushes gases out.

Mechanical Transmissions

Mechanisms or mechanical transmissions modify engine force or speed:

  • Transmit mechanical energy using shafts, belts, chains, levers, etc.
  • Transform force or speed using pulleys, chains, gears, etc.
  • Modify movement for linear displacement using cams, eccentrics, cranks, screws, or rack and pinion.
  • Regulate and control movement using flywheels, brakes, ratchets, or electronic devices.
Types of Transmission
  • Linear transmission: Toggle levers vary force and path.
  • Circular transmission: Pulley diameter or gear teeth change angular velocity.
  • Circular-linear transmission: Cams, eccentrics, or cranks convert rotation to reciprocating displacement.
  • Regulation of movement: Inertia voters maintain constant speed; brakes transform energy into heat.

Automatic Functions

Machines often have automatic functions performed without direct intervention:

  • Remote controls: Turn machines on/off using signals.
  • Timers: Select operating time or start automatically.
  • Maneuver devices: Modify actions using steering wheels, pedals, or switches.
  • Boot switches: Turn machines on/off.
  • Operation selectors: Choose performance options or programs.
Automatic Operation Devices
  • Control units: Process data and order tasks.
  • Sensors: Detect changes in the environment.
  • Control devices: Act as switches or valves to modify operation.
Automatic Control
Gear Ratios

Mechanisms modify rotation speed or force. The ratio is represented by ‘I’.

  • In levers, increasing distance increases effort.
  • In worm transmission, each screw turn shifts a pinion tooth.
  • In circular transmissions, increasing pulley diameter or teeth increases turning force.
  • In circular-to-linear motion, determine linear element paths per turn.