How does a garbage truck swallow so many bins?

A garbage truck may empty many bins before it leaves the neighborhood. The rubbish does not vanish inside. The truck lifts it in, then squeezes some of the empty spaces out of the load.

On one kind of truck, an arm grips a bin at the side. Powered joints raise the arm and turn the bin upside down over an opening. Gravity pulls the rubbish out. The arm then returns the empty bin to the ground.

Inside, a strong moving panel pushes the rubbish farther into the truck. Boxes crumple and bags press together. Spaces between objects get smaller, so more rubbish can fit. Heavy parts use oil-powered cylinders to push and lift.

Squeezing makes the load smaller in size, but it does not make the rubbish weigh less. The truck still has to carry all that weight. Later, the load is emptied at a collection facility. Lifting, squeezing and carrying are three different jobs in one vehicle.