Totally enclosed door check

A method of linearly dampening the closing motion of a door, said door being attached to a dampening assembly comprising a housing having a central chamber therein closed at first and second ends, compressible fluid in the chamber, and a piston slidably mounted in said chamber movable between said ends, said piston being attached to said door, the steps comprising

• continuously communicating said fluid from a first portion of said chamber between said first end and said piston to a second portion of said chamber between said second end and said piston such that as said piston moves from said first end toward said second end, fluid in said second portion may flow to said first portion of the chamber as said door opens,
• continuously communicating said fluid from said second portion of said chamber such that as said door closes moving said piston from said second end toward said first end, said fluid in said first portion of the chamber flows to said second portion of the chamber, and
• controlling the rate of flow of said fluid from said first portion of said chamber to said second portion of the chamber during closing of said door to maintain linear dampening of said door at a desired rate by controlling the magnitude of a vacuum in said second portion of said chamber created by the movement of said second piston.

An apparatus using compressible fluid for checking the motion of an element comprising

• a hollow housing having a cavity therein containing a quantity of compressible fluid,
• a movable element having first and second sides slidably mounted within said cavity and attached to said element so as to move within said cavity and against said fluid as said element moves,
• a passage placing said sides of said element in continuous fluid communication and variable orifice means in said passage for controlling the flow rate of said fluid in said passage whereby as said element moves in a given direction, fluid in front of said element in the direction of movement continuously flows to the other side of said member such that said orifice means controls the magnitude of a vacuum on said other side of said element created by the movement of said element thereby controlling the compression of said fluid in front of said element and the resistance to the movement of said element.