Rotary-linear transformation

Wheel

Wheels are essential parts of bicycles. They let us move more easily because they reduce our contact with the ground and decrease friction. However, if there isn't enought friction, the wheels can slide out of control.  

Rack and pinion mechanisms
A rack and pinion mechanisms has two parts. The rack is a bar with many teeth and the pinion is a gear with teeth that interlock with the rack. When the pinion rotates, the rack moves in a linear direction.If the mechanisms is reversible, the pinion also rotates when the rack moves..






Nut and bolt mechanism
A nut and bolt mechanisms transforms rotary motion  into linear motion. It has two parts: a bolt or a shaft with a spiral groove and a nut that turns around it. We can use a nut and bolt mechanism to lift loads because it funtions as a reducing system.








Whinch and crank mechanism 
A whinch is a cylinder that rotates around a horizontal axis. We attacha rope to the tothe winch and to a load. Then we turn the crank to rotate the winch. We use winches for lifting loads. We find them in cronstruction cranes and in the mechanism that raises window blinds in our homes.