Garbage Truck:

The modern rear loader usually compacts the waste using a hydraulically powered mechanism that employs a moving plate or shovel to scoop the waste out from the loading hopper and compress it against a moving wall. In most compactor designs, the plate has a pointed edge (hence giving it the industry standard name packer blade) which is designed to apply point pressure to the waste to break down bulky items in the hopper before being drawn into the main body of the truck.