# Simple machine: Rigging

## Potential tackle

System of pulleys consisting mainly of a fixed pulley and one or more mobile pulleys. It allows to lift heavy bodies with little effort.

Its basic scheme is:

Scheme of a potential rig

Its formula is:

T = | P |

2 ^{N.} |

Where,

T: voltage (power) (N)

P: Weight (N)

N: Number of mobile pulleys

## Fairy Fairy

System of lifting consisting of equal amount of mobile and fixed pulleys. It allows to lift heavy bodies, the more pulleys it has less will be the effort. It is very employed and is less efficient than potential rigging.

Its basic scheme is:

Scheme of a factorial rig

Its formula is:

T = | P |

2 · N. |

Where,

T: voltage (power) (N)

P: Weight (N)

N: Number of mobile pulleys

## Differential rigging

Pulley system consisting mainly of two concentric pulleys with different diameter and with the same rotation axis, and a mobile pulley. It allows to lift heavy bodies with little effort. Its basic scheme is:

Scheme of a differential rig

This type of rigging is very common in mechanical workshops.

Its formula is:

F = | D – D. | · P. |

2 · D. |

F: Strength or power to lift the weight (N).

D: diameter of the Pulley Mayor (M).

D: Diameter of the Menor Pulley (M).

Q: Weight or resistance to lift (N).

or

F = | R – R. | · P. |

2 · R. |

F: Strength or power to lift the weight (N).

A: Diameter of the Pulley Mayor (M).

A: Diameter of the lower pulley (M).

Q: Weight or resistance to lift (N).

## Turnstile

The lathe is a simple machine that is used to lower or lift weights. It consists of a cylinder and a crank that rotate together around the same axis as the figure shows.

Scheme of a lathe

Its formula is:

F · r = p · r

Where:

F: Strength or power (N).

P: weight or resistance (N).

A: Length of the crank (radius) (M).

A: Cylinder radius (M).

Later:

M P = p · R (moment of resistance) (n · m)

M _{F} = F · R (Moment of Force) (N · M)