TRANSMISIÓN Y TRANSFORMACIÓN DEL MOVIMIENTO

Introduction to Mechanisms of Motion Transmission and Transformation

Overview of Motion Mechanisms

• The video introduces mechanisms for transmitting and transforming motion, categorizing them based on the type of input and output movement.

• Mechanisms are grouped into those that transmit linear motion in a linear manner or circular motion in a circular manner, versus those that transform one type of motion into another.

Linear to Linear Motion Transmission

• Examples include pulleys and levers; pulleys change the direction of force, making it easier to lift loads by pulling down to raise an object.

• A block-and-tackle system (polipasto) combines fixed and movable pulleys, serving as a force multiplier while changing the direction of movement.

Circular Motion Transmission Systems

• Circular motion can be transmitted through friction or gears, often requiring changes in rotational direction.

• Cylindrical friction wheels can transfer motion between parallel axes but require high friction coefficients to prevent slipping.

Limitations of Friction-Based Systems

• Over time, friction systems lose grip and efficiency; they cannot handle large forces due to slippage issues.

• Open or crossed belt pulleys rotate in the same or opposite directions respectively; crossing belts may cause frictional heat leading to wear.

Gear Mechanisms

• Gears consist of toothed wheels (crown and pinion), designed to enhance power transmission without slipping. They come in cylindrical or conical shapes with straight or helical teeth.

• Gears can operate on parallel axes or intersecting axes at 90 degrees; most invert rotation except for specific internal gears.

Advanced Circular Motion Transmission

Screw Mechanism

• The screw gear mechanism consists of a small gear (pinion/screw) driving a larger gear (crown), allowing perpendicular axis operation while providing significant effort transmission compared to other methods.

Chain Drive Systems

• Chain-driven systems are commonly used in bicycles, effectively transferring power over distance between parallel axes while maintaining synchronized rotation.

Transforming Motion: From Circular to Linear

Key Transformation Mechanisms

• The presentation highlights two primary systems that convert circular motion into linear: the pinion-rack system used in sliding doors and the screw mechanism found in vices.

Pinion-Rack System

• This system uses a small gear (pinion) moving along a toothed bar (rack), commonly seen in garage doors for smooth operation.

Screw Mechanism

• In this setup, turning the screw results in linear displacement, exemplified by bench vices where rotating handles move jaws linearly.

Alternative Movement Transformations

Lever and Follower System

Mechanisms of Motion: Understanding Followers and Their Functions

The Role of Gravity and Springs in Mechanisms

• Two mechanisms require assistance from gravity or a spring to return the follower to its initial position. A green eccentric disk is used, which aligns the geometric axis with the rotation axis but does not transmit any movement.

Transformation of Circular to Alternative Motion

• In the center, there is a different red follower mechanism. Through articulated rods, circular motion from a crank is transformed into alternative motion.

Reversibility of Motion Types

• This transformation is reversible; circular input can yield alternative output and vice versa. However, both cam and eccentric mechanisms are non-reversible.

Limitations of Cam and Eccentric Mechanisms