Patent ID: 8813527

Claim:
A washing machine appliance, comprising: a cabinet; a wash tub supported in said cabinet; a wash basket rotatably mounted in said wash tub; and a pneumatic variable damping device extending between the wash tub and the cabinet in order to couple the wash tub to the cabinet, the pneumatic variable damping device comprising a sealed cylinder comprising a first chamber and a second chamber; a piston slidably mounted in said cylinder, said piston separating said first chamber from said second chamber; a first valve in fluid communication with said first chamber, said first valve permitting free flow of pneumatic fluid into said first chamber and permitting restricted flow of pneumatic fluid from said first chamber, said first valve being the only inlet and outlet through said sealed cylinder for pneumatic fluid within said first chamber; and a second valve in fluid communication with said second chamber, said second valve permitting free flow of pneumatic fluid into said second chamber and permitting restricted flow of pneumatic fluid from said second chamber, said second valve being the only inlet and outlet through said sealed cylinder for pneumatic fluid within said second chamber; wherein said first valve permits free flow of pneumatic fluid into said first chamber and said second valve permits restricted flow of pneumatic fluid out of said second chamber whenever said piston moves in a first direction within said cylinder; wherein said second valve permits free flow of pneumatic fluid into said second chamber and said first valve permits restricted flow of pneumatic fluid out of said first chamber whenever said piston moves in a second direction within said cylinder, the second direction being opposite the first direction; and wherein pneumatic fluid flowing through the first and second valves increases a damping ratio of the pneumatic variable damping device when an amplitude of displacement of the piston increases and decreases the damping ratio of the pneumatic variable damping device when the amplitude of displacement of the piston decreases.