Motion Transmission and Transformation Mechanisms

Posted on Mar 5, 2025 in Technology

Mechanisms: Transmission and Transformation of Movement

A) Mechanisms of Transmission of Movement

These mechanisms transmit the motion produced by a driving element to another point.

  1. Linear Transmission:
    • Lever: A horizontal bar that rotates around a support point. There are three types (1st, 2nd, and 3rd class) depending on the position of the support point, effort, and resistance.
    • Fixed Pulley: A grooved wheel that revolves around an axis.
    • Mobile Pulley: A set of two pulleys, one fixed and the other movable.
    • Block and Tackle: A system of fixed and mobile pulleys.
  2. Circular Transmission:
    • Pulley Train with Belt: A pulley system with more than two pulleys connected by a belt.
    • Gear Train: A system consisting of more than two gears.
    • Friction Wheels: Two or more wheels that are in contact.
    • Belt-Pulley Systems: Two pulleys or wheels at a distance, with parallel axes, rotating simultaneously.
    • Gears: Sets of wheels with protruding teeth that fit together.
    • Worm Gear: A screw that engages a cogwheel whose axes are perpendicular.
    • Chain Gear Systems: Two parallel shaft gear wheels rotating simultaneously due to the effect of a metal chain.

B) Mechanisms of Transformation of Movement

These mechanisms transform circular motion into rectilinear motion or vice versa.

  1. Rectilinear Transformation of Circular Motion (TMC):
    • Rack and Pinion: A gear with straight teeth (pinion) engaging with a rack.
    • Screw-Nut System: Consists of a screw and a nut with matching inner diameter.
    • Crank Assembly (Lathe): A bar attached to a spinning wheel spindle.
  2. Alternative Rectilinear TMC:
    • Rod-Crank: Consists of a handle and a bar (connecting rod), articulated by a crank. One end describes an alternative movement.
    • Crankshaft: Rods are bent on the same route, acting as an alternative crank.
    • Cam: A projection that pushes a follower in a specific way, allowing for more complex movements.
    • Eccentric: A wheel whose rotational axis does not match the center of the circle, transforming rotational movement into linear alternate movement.

Structures

A structure is the set of elements of a body designed to withstand the effects of loads without breaking or deforming excessively. It must satisfy these properties:

  • Stability: Its center of gravity must be at the center.
  • Resistance: Withstanding stress without breaking.
  • Rigidity: Avoiding excessive deformation.

Stress

Stress is the internal tension experienced by bodies under the action of one or more forces. Types of stress include:

  • Tension: Forces trying to stretch the body.
  • Compression: Forces trying to crush a body.
  • Bending: Forces trying to bend the element.
  • Torsion: Forces trying to twist the element.
  • Shear: Forces acting like a double-edged scissor, one upward and one downward.
  • Buckling: A combination of compression and bending stress.

Types of Structures

  • Massive: Large amounts of material with few gaps.
  • Framing: Made of concrete and steel, like in buildings.
  • Vaulted: Arches and domes to cover spaces.
  • Triangulated: Wooden or metal bars forming triangles.
  • Pneumatic: Removable and light, containing air inside.
  • Hanging: Cables and straps, with tensioners.
  • Laminar: Thin, high-strength sheets.
  • Geodesic: Combining three-dimensional triangulated bars and vaults.

Mechanisms

Mechanisms are elements designed to transmit and transform forces and movements from a driving element to a receiver.