Patent ID: 8348028
Filing Date: 2013-01-08
Classification: F16F

Abstract:
1. A pneumatic damper for slowing down movable furniture parts, comprising a cylinder ( 11 , 81 ) with a cylinder wall ( 12 ), a piston ( 30 ) movably supported, and axially guided, in said cylinder ( 11 , 81 ) and including a piston rod ( 70 , 85 ) having a diameter of less than 35% of the diameter of said piston ( 30 ) and extending from one end of said cylinder ( 11 , 81 ) through a guide opening ( 18 ), in which said piston rod ( 70 , 85 ) is sealingly supported, said piston ( 30 ) having a rest position at said one end of said cylinder and dividing said cylinder ( 11 , 81 ) into a vacuum chamber ( 16 ) at the side of the piston adjacent said one end of the cylinder ( 11 , 81 ) and a displacement chamber ( 15 ) at the opposite side of the piston ( 30 ), said piston ( 30 ) being void of any throttling passages and including circumferential sealing and elastic sleeve elements ( 50 , 60 ), which are in contact with the cylinder wall ( 12 ) in said rest position of the piston ( 30 ) such that the vacuum chamber ( 16 ) and the displacement chamber ( 15 ) are sealed from each other, said sealing and elastic sleeve elements ( 50 , 60 ) permitting pneumatic fluid flow only from the vacuum chamber ( 16 ) at one side of the piston ( 30 ) to the displacement chamber ( 15 ) at the other side of the piston ( 30 ) when the piston ( 30 ) is moved back to its rest position, and said sealing and elastic sleeve elements ( 50 , 60 ) including an elastic sleeve ( 60 ), whose interior is in communication with said displacement chamber ( 15 ) for biasing said elastic sleeve ( 60 ) into contact with the cylinder wall ( 12 ) for generating friction forces retarding the movement of the piston ( 30 ) while the fluid in the displacement chamber ( 15 ) is under pressure, said cylinder ( 11 , 81 ) having a diameter which increases from the rest position of said piston ( 30 ) in which said sealing elements ( 50 , 60 ) are in contact with the cylinder wall ( 12 ) toward the opposite end thereof, so that a vacuum is rapidly generated in the vacuum chamber ( 16 ) at said one side of the piston as said piston is moved out of its rest position while the fluid in said displacement chamber ( 15 ) is compressed, but pressurized fluid is released from the displacement chamber ( 15 ) as the piston approaches the end of the displacement chamber ( 15 ) opposite the rest position of the piston ( 30 ) where the cylinder ( 11 , 81 ) has an increased diameter so that the piston sealing and elastic sleeve elements ( 50 , 60 ) are no longer in sealing contact with the cylinder wall.