Adjustable-length gas spring
An adjustable length gas spring comprises a casing and a piston which is disposed for displacement in the casing and joined to a piston rod. An externally operable adjusting valve is formed in the piston. Further, the piston is provided with a traction valve, which, upon application of tractive force from outside, cancels any blockage of the piston.
1. An adjustable-length gas spring, comprising
a casing ( 1 ) which has a central longitudinal axis ( 2 ) and is filled with a liquid pressure fluid;
a guide and seal unit ( 10 ) which closes the casing ( 1 ) at a first end;
a piston rod ( 8 ) for sealed guidance through the guide and seal unit ( 10 ) out of the first end of the casing ( 1 );
a piston ( 9 ) for sealed guidance in the casing ( 1 ), the piston ( 9 ) being joined to the piston rod ( 8 );
a first divisional interior chamber ( 7 b ) which is formed between the piston ( 9 ) and the guide and seal unit ( 10 );
a second divisional interior chamber ( 7 a ) which is defined by the piston ( 9 ) and turned away from the first divisional interior chamber ( 7 b );
an adjusting valve ( 37 ) which is disposed in the piston ( 9 ) and interconnects the first and second divisional interior chamber ( 7 a , 7 b ), having
a valve control pin ( 20 ) which is displaceable in a direction of the central longitudinal axis ( 2 ),
a valve tray ( 21 ) which is mounted on the valve control pin ( 20 ),
a first sealing seat ( 24 ), and
a first sealing contact surface which cooperates with the first sealing seat ( 24 ),
the first sealing seat ( 24 ) and the first sealing contact surface being liftable off each other by means of the valve control pin ( 20 );
a traction valve ( 38 ), which is disposed on the piston ( 9 ), for interconnection of the first and second divisional interior chamber ( 7 a , 7 b ) when tractive force acts between the piston rod ( 8 ) and the casing ( 1 ), the traction valve ( 38 ) having
a second sealing seat ( 32 ), and
a second sealing contact surface that cooperates with the second sealing seat ( 32 ),
the second sealing seat ( 32 ) and the second sealing contact surface, upon increase of pressure in the first divisional interior chamber ( 7 b ), being liftable off each other while the traction valve ( 38 ) opens; and
the adjusting valve ( 37 ) and the traction valve ( 38 ) having a joint sliding bush ( 26 ) which is guided for displacement on the valve control pin ( 20 ) in the direction of the central longitudinal axis ( 2 ) and bears either the first or second sealing contact surface or the first or second sealing seat ( 24 , 32 ).
2. An adjustable-length gas spring, comprising
a casing ( 1 ) which has a central longitudinal axis ( 2 ) and is filled with a liquid pressure fluid;
a guide and seal unit ( 10 ) which closes the casing ( 1 ) at a first end;
a piston rod ( 8 ) for sealed guidance through the guide and seal unit ( 10 ) out of the first end of the casing ( 1 );
a piston ( 9 ) for sealed guidance in the casing ( 1 ), the piston ( 9 ) being joined to the piston rod ( 8 );
a first divisional interior chamber ( 7 b ) which is formed between the piston ( 9 ) and the guide and seal unit ( 10 );
a second divisional interior chamber ( 7 a ) which is defined by the piston ( 9 ) and turned away from the first divisional interior chamber ( 7 b );
an adjusting valve ( 37 ) which is disposed in the piston ( 9 ) and interconnects the first and second divisional interior chamber ( 7 a , 7 b ), having
a valve control pin ( 20 ) which is displaceable in a direction of the central longitudinal axis ( 2 ),
a valve tray ( 21 ) which is mounted on the valve control pin ( 20 ),
a first sealing seat ( 24 ), and
a first sealing contact surface which cooperates with the first sealing seat ( 24 ),
the first sealing seat ( 24 ) and the first sealing contact surface being liftable off each other by means of the valve control pin ( 20 );
a traction valve ( 38 ), which is disposed on the piston ( 9 ), for interconnection of the first and second divisional interior chamber ( 7 a , 7 b ) when tractive force acts between the piston rod ( 8 ) and the casing ( 1 ), the traction valve ( 38 ) having
a second sealing seat ( 32 ), and
a second sealing contact surface that cooperates with the second sealing seat ( 32 ),
the second sealing seat ( 32 ) and the second sealing contact surface, upon increase of pressure in the first divisional interior chamber ( 7 b ), being liftable off each other while the traction valve ( 38 ) opens; and
the adjusting valve ( 37 ) and the traction valve ( 38 ) having a joint sliding bush ( 26 ) which is guided for displacement on the valve control pin ( 20 ) in the direction of the central longitudinal axis ( 2 ) and bears either the first or second sealing contact surface or the first or second sealing seat ( 24 , 32 ),
wherein the adjusting valve ( 37 ), when shut off, has a surface F 37 which is in connection with the first divisional interior chamber ( 7 b );
wherein the traction valve ( 38 ), when shut off, has a surface F 38 which is in connection with the first divisional interior chamber ( 7 b ); and
wherein F 38 >F 37 applies.
3. A gas spring according to claim 1 , wherein the sliding bush ( 26 ) has passages ( 27 ) which are allocated to the adjusting valve ( 37 ) and the traction valve ( 38 ).
4. An adjustable-length gas spring, comprising
a casing ( 1 ) which has a central longitudinal axis ( 2 ) and is filled with a liquid pressure fluid;
a guide and seal unit ( 10 ) which closes the casing ( 1 ) at a first end;
a piston rod ( 8 ) for sealed guidance through the guide and seal unit ( 10 ) out of the first end of the casing ( 1 );
a piston ( 9 ) for sealed guidance in the casing ( 1 ), the piston ( 9 ) being joined to the piston rod ( 8 );
a first divisional interior chamber ( 7 b ) which is formed between the piston ( 9 ) and the guide and seal unit ( 10 );
a second divisional interior chamber ( 7 a ) which is defined by the piston ( 9 ) and turned away from the first divisional interior chamber ( 7 b );
an adjusting valve ( 37 ) which is disposed in the piston ( 9 ) and interconnects the first and second divisional interior chamber ( 7 a , 7 b ), having
a valve control pin ( 20 ) which is displaceable in a direction of the central longitudinal axis ( 2 ),
a valve tray ( 21 ) which is mounted on the valve control pin ( 20 ),
a first sealing seat ( 24 ), and
a first sealing contact surface which cooperates with the first sealing seat ( 24 ),
the first sealing seat ( 24 ) and the first sealing contact surface being liftable off each other by means of the valve control pin ( 20 );
a traction valve ( 38 ), which is disposed on the piston ( 9 ), for interconnection of the first and second divisional interior chamber ( 7 a , 7 b ) when tractive force acts between the piston rod ( 8 ) and the casing ( 1 ), the traction valve ( 38 ) having
a second sealing seat ( 32 ), and
a second sealing contact surface that cooperates with the second sealing seat ( 32 ),
the second sealing seat ( 32 ) and the second sealing contact surface, upon increase of pressure in the first divisional interior chamber ( 7 b ), being liftable off each other while the traction valve ( 38 ) opens; and
the adjusting valve ( 37 ) and the traction valve ( 38 ) having a joint sliding bush ( 26 ) which is guided for displacement on the valve control pin ( 20 ) in the direction of the central longitudinal axis ( 2 ) and bears either the first or second sealing contact surface or the first or second sealing seat ( 24 , 32 ), wherein the sliding bush ( 26 ) supports a valve disk ( 29 ) on which the first sealing contact surface and the second sealing contact surface are formed.
5. A gas spring according to claim 4 , wherein the valve disk ( 29 ) comprises sealing material on both sides.
6. A gas spring according to claim 4 , wherein a gap ( 39 ) is formed between the valve disk ( 29 ) and an inside wall ( 19 ) that defines the divisional interior chambers ( 7 a , 7 b ).
7. An adjustable-length gas spring, comprising
a casing ( 1 ) which has a central longitudinal axis ( 2 ) and is filled with a liquid pressure fluid;
a guide and seal unit ( 10 ) which closes the casing ( 1 ) at a first end;
a piston rod ( 8 ) for sealed guidance through the guide and seal unit ( 10 ) out of the first end of the casing ( 1 );
a piston ( 9 ) for sealed guidance in the casing ( 1 ), the piston ( 9 ) being joined to the piston rod ( 8 );
a first divisional interior chamber ( 7 b ) which is formed between the piston ( 9 ) and the guide and seal unit ( 10 );
a second divisional interior chamber ( 7 a ) which is defined by the piston ( 9 ) and turned away from the first divisional interior chamber ( 7 b );
an adjusting valve ( 37 ) which is disposed in the piston ( 9 ) and interconnects the first and second divisional interior chamber ( 7 a , 7 b ), having
a valve control pin ( 20 ) which is displaceable in a direction of the central longitudinal axis ( 2 ),
a valve tray ( 21 ) which is mounted on the valve control pin ( 20 ),
a first sealing seat ( 24 ), and
a first sealing contact surface which cooperates with the first sealing seat ( 24 ),
the first sealing seat ( 24 ) and the first sealing contact surface being liftable off each other by means of the valve control pin ( 20 );
a traction valve ( 38 ), which is disposed on the piston ( 9 ), for interconnection of the first and second divisional interior chamber ( 7 a , 7 b ) when tractive force acts between the piston rod ( 8 ) and the casing ( 1 ), the traction valve ( 38 ) having
a second sealing seat ( 32 ), and
a second sealing contact surface that cooperates with the second sealing seat ( 32 ),
the second sealing seat ( 32 ) and the second sealing contact surface, upon increase of pressure in the first divisional interior chamber ( 7 b ), being liftable off each other while the traction valve ( 38 ) opens; and
the adjusting valve ( 37 ) and the traction valve ( 38 ) having a joint sliding bush ( 26 ) which is guided for displacement on the valve control pin ( 20 ) in the direction of the central longitudinal axis ( 2 ) and bears either the first or second sealing contact surface or the first or second sealing seat ( 24 , 32 ),
wherein the first sealing seat ( 24 ) has the shape of a circular ring and a diameter D 24 ; and wherein the second sealing seat ( 32 ) has the shape of a circular ring and a diameter D 32 ; and wherein D 32 >D 24 applies.
8. A gas spring according to claim 1 , wherein an equalization chamber is provided, which is filled with compressed gas and connected to one of the divisional interior chambers ( 7 b ).
9. A gas spring according to claim 8 ,
wherein the divisional interior chambers ( 7 a , 7 b ) are formed in an internal cylinder ( 3 ) which, concentrically of the central longitudinal axis ( 2 ), is enveloped by a casing ( 1 );
wherein an annular chamber ( 4 ), which is formed between the casing ( 1 ) and the internal cylinder ( 3 ), is divided by a dividing piston ( 12 ) into a divisional annular chamber ( 4 a ) filled with compressed gas and a divisional annular chamber ( 4 b ) filled with liquid pressure fluid; and
wherein the divisional annular chamber ( 4 b ), which is filled with pressure fluid, is permanently connected to the first divisional interior chamber ( 7 b ) via a connecting conduit ( 11 ).