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Mechanisms: - Coggle Diagram
Mechanisms:
Friction drives: Friction drives are made up of two or more wheels that are in contact. The first wheel is called the primary drive wheel. when it moves, it turns or drives the second or output wheel, causing it to move as well.
Pulleys with belt: They consist of two pulleys or wheels that are a certain distance apart. Their axles are parallel and they rotate simultaneously due to the effect of the belt. The rotation of one axle is transmited to the other through the connected pulleys. The two pulleys, and the two axles are in the same direction.
Gear mechanisms and cogwheels: Cogwheels are sets of wheels that have teeth called cogs.
The cogs fit into the spaces between the two connected axles, which can be parallel, perpendicular or oblique.
Gears cn be cylindrical or conical.
All the teeth must be the same shape and size.
The two wheels an the two axles rotate in opposite directions.
The ratio between the rotation velocities of the wheels depends on the number of teeth on each wheel. It's expressed by this equation:
N¹ x Z¹ = N² x Z² - Z¹ / Z² = N² / N¹
Worm Gear: This is a screw that moves a helical cogwheel that is set perpendicular to the screw.
Each time the screw rotates, the gear moves forward as many teeth as there are grooves in the screw, usually a small number: 1,2 and 3.
This is used to reduce velocity as well as functioning as a brake system.
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Gear mechanisms with a chain: The relation between the rotation velocities of the wheels dependss on the number of teeth on each gear: N¹ · Z¹ = N² · Z² ---) Z¹ / Z² = N² / N¹
Gear train: This is a system of more than two gears, connected together as shown in the diagram. The rotary motion of the first wheel drives the second wheel and so on.
In this system, the rotary movement of the first axle is transmitted to the second by means of wheels 1 and 2.
Theel 3 rotates with the same velocity as wheel 2 and drives wheel 4, to which it's connected.
Each connected geared wheel rotates in the opposite direction to the wheel it's attached to.
The gear ratio between the drive wheel and the driven wheel depends on the number of geared teeth in the system:
N⁴ / N¹ = Z¹ · Z³ / Z² · Z⁴
Pulley trains with belts:
The rotary motion of axle 1 is transmitted to axle 2 by the belt that connects them.
Pulleys 2 and 3 rotate at the same velocity.
The motion of pulley 3 is transmitted to pulley 4 by the belt that connects them.
All the wheels rotate in the same direction.
The gear ratio between the drive pulley (1) and the driven pulley (4) depends on the relative size of the pulleys in the system. It's expressed as a function of the diameters.
N⁴ / N¹ = D¹ · D³ / D² · D⁴.
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Fixed pulley: A fixed pulley is a wheel that has a groove around it into which a rope, chain or belt fits.
A fixed pulley is balanced when the effort F is equal to the resistance of the load, R: F = R.
Moveable pulley: A moveable pulley is a set of two pulleys - one is fixed while the other can move in a linear direction.
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Compound pulley: This is a system of fixed and moveable pulleys, often called block and tackle. If we use more pulleys, the system becomes more complex, but less effort is needed to move the load.
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- Mechanisms that transform motion
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Around us we can see many moving objects and mechanisms that produce movement that we can also call motion.
Mechanisms are devices that transmit and convert forces and motion from a driving force or input element or output element. They allow us to carry out certain tasks more easily and more efficiently.