Hydraulic damper for furniture doors and drawers
Hydraulic damper( 1000 ) for furniture doors or drawers. Damper( 1000 ) comprises housing( 1 ) having a closed first end( 14 ) and a second end provided with lid( 7 ); and piston( 2 ) movable in housing( 1 ) along longitudinal piston axis(A). Piston( 2 ) defines first and second chambers( 11,12 ) inside housing( 1 ), respectively at first and second end-sides of piston( 2 ). Piston( 2 ) comprises circumferential groove( 24 ) defined between circumferential first and second shoulders( 241,242 ). Groove( 24 ) is provided with annular collar( 5 ) axially movable between first and second shoulders( 241,242 ). Collar( 5 ) is formed from elastic material to reversibly contact inner surface( 13 ) of housing( 1 ) when radially expanded when subjected to hydraulic-pressure forces parallel to axis(A). First shoulder( 241 ) is arranged allowing hydraulic fluid to flow on collar( 5 ) when collar( 5 ) contacts first shoulder( 241 ). Second shoulder( 242 ) is arranged blocking hydraulic fluid from flowing on collar( 5 ) when collar( 5 ) contacts second shoulder( 242 ). Piston( 2 ) is provided with channel( 21 ) arranged to provide fluid flow communication between first and second chambers( 11,12 ).
1 . A hydraulic damper ( 1000 ) for use in furniture doors or drawers, the damper ( 1000 ) comprising a housing ( 1 ) that has a closed first end ( 14 ) and a second end that is provided with a lid ( 7 ); the damper ( 1000 ) further comprises a piston ( 2 ) that is movable in the housing ( 1 ) along a longitudinal piston axis (A); a piston rod ( 3 ) connected to the piston ( 2 ); the housing ( 1 ) is divided by the piston ( 2 ) to define a first chamber ( 11 ) and a second chamber ( 12 ) that are respectively at a first end side and a second end side of the piston ( 1 ); wherein
the piston ( 2 ) comprises a circumferential groove ( 24 ) that is defined between a circumferential first shoulder ( 241 ) and a circumferential second shoulder ( 242 ) provided at a second end side with regard to the first shoulder ( 241 );
the piston rod ( 3 ) activating a damping of the piston ( 2 );
the groove ( 24 ) is provided with an annular collar ( 5 ) that is axially movable between the first shoulder ( 241 ) and second shoulder ( 242 );
the collar ( 5 ) is formed from an elastic material, and is arranged to reversibly contact to an inner surface ( 13 ) of the housing ( 1 ) when radially expanded when subjected to hydraulic pressure forces that are parallel to the axis (A);
the first shoulder ( 241 ) is arranged to allow hydraulic fluid to flow on the collar ( 5 ) when the collar ( 5 ) is brought into contact with the first shoulder ( 241 );
the second shoulder ( 242 ) is arranged to block hydraulic fluid from flowing on the collar ( 5 ) when the collar ( 5 ) is brought into contact with the second shoulder ( 242 );
the piston ( 2 ) is provided with a channel ( 21 ) that is arranged to provide fluid flow communication between said first chamber ( 11 ) and second chamber ( 12 );
the collar ( 5 ) comprises a circumferential outer surface ( 51 ) facing the inner surface ( 13 ) of the housing ( 1 ), the outer surface ( 51 ) having a cylinder side surface geometry with a height (L);
at zones that correspond to a trajectory of the piston ( 2 ) at its reciprocations along the axis (A), the inner surface ( 13 ) of the housing ( 1 ) has an inner diameter (D 1 ) radial to said axis (A); and
an L/D ratio between said height (L) and said inner diameter (D 1 ) is 0.3 or higher.
2 . Damper according to claim 1 , wherein the channel ( 21 ) is arranged to provide a fluid flow communication between the second chamber ( 12 ) and the groove ( 24 ).
3 . Damper according to claim 2 , wherein the groove ( 24 ) is provided with a hole ( 23 ) connected to the channel ( 21 ).
4 . Damper according to claim 3 , wherein the collar ( 5 ) is shaped and sized to, delimit the fluid communication through the hole ( 23 ) when in contact with the first shoulder ( 241 ) and relatively increase the fluid flow communication through the hole ( 23 ) when in contact with the second shoulder ( 242 ).
5 . Damper according to claim 1 , wherein the first shoulder ( 241 ) comprises a plurality of radial indentations to provide a local diameter (D 2 ) value smaller than a corresponding local inner diameter of the collar ( 5 ).
6 . Damper according to claim 1 , provided with a seal ( 4 ) circumferentially disposed around the piston rod ( 3 ), arranged for preventing hydraulic liquid leakage from the second chamber ( 12 ) towards the lid ( 7 ).
7 . Damper according to claim 6 , provided with a first elastic means ( 8 ) in-between the lid ( 7 ) and the seal ( 4 ), for biasing the seal ( 4 ) away from the lid ( 7 ).
8 . Damper according to claim 6 , wherein the housing ( 1 ) is provided with an extended diameter (D 3 ) around a locus of the seal ( 4 ) to have a value that is higher than an inner diameter (D 1 ) of the housing ( 1 ) at the first chamber ( 11 ) and second chamber ( 12 ).
9 . Damper according to claim 7 , provided with a supporting means ( 6 ) in-between the seal ( 4 ) and first elastic means ( 8 ), arranged for bearing the first elastic means ( 8 ) and for uniformly distributing the mechanical forces from the first elastic means ( 8 ) onto the seal ( 4 ).
10 . Damper according to claim 1 , provided with a second elastic means ( 9 ) disposed between the first end ( 14 ) and the piston ( 2 ), arranged for biasing the piston ( 2 ) away from the first end ( 14 ).
11 . Damper according to claim 1 , wherein said L/D ratio is 0.4 or higher.
12 . A furniture hinge provided with a damper according to claim 1 .
13 . A furniture drawer provided with a damper according to claim 1 .