This mechanism is composed of three important parts:

The crank which is the rotating disc, the slider which slides inside the tube and the connecting rod which joins the parts together.

As the slider moves to the right the connecting rod pushes the wheel round for the first 180 degrees of wheel rotation. When the slider begins to move back into the tube, the connecting rod pulls the wheel  round to complete the rotation.

One of the best examples of a crank and slider mechanism is a steam train. Steam pressure powers the slider mechanism as the connecting rod pushes and pulls the wheel round.

The cylinder of an internal combustion engine is another example of a crank and slider mechanism