Extension spring strut

1. An extension spring strut, comprising

a helical extension spring ( 1 ) having

a first end, and

a second end; and

a pre-load, which is increased on elongating the spring ( 1 ) and is released on linear contraction of the spring ( 1 ),

a damper ( 4 ),

which is disposed inside the extension spring ( 1 ),

which has a housing ( 6 ) that is supported on the first end of the extension spring ( 1 ) and is filled with a damping fluid, and

which has a damping piston ( 7 ) disposed in the housing ( 6 ); and

which has a piston rod ( 8 ) that is mounted on the damping piston ( 7 ) and extended from the housing ( 6 ) and movable over a damping range a and directed into the extension spring ( 1 ); and

an operating element ( 5 ),

which comprises an actuating tappet ( 11 ),

which is separated from the piston rod ( 8 ),

which is connected with the second end of the extension spring ( 1 ), and

which is movable over a total range c that includes a no-load range b of the actuating tappet ( 11 ) whereby the actuating tappet ( 11 ) is not in contact with the piston rod ( 8 ) and that includes the damping range a of the piston rod ( 8 ) whereby the actuating tappet ( 11 ) is in contact with the piston rod ( 8 ).

2. The extension spring strut according to claim 1 , wherein b>a applies to the damping range a to no-load range b ratio.

3. The extension spring strut according to claim 1 , wherein the actuating tappet ( 11 ) is disposed for displaceable guidance in a guide tube ( 10 ).

4. The extension spring strut according to claim 3 , wherein the guide tube ( 10 ) is coaxially joined to the housing ( 6 ) of the damper ( 4 ).

5. The extension spring strut according to claim 1 , wherein the extension spring strut is longitudinally adjustable.

6. The extension spring strut according to claim 1 , wherein the damper ( 4 ) is a hydraulic damper.

7. An extension spring strut, comprising

a pre-loaded extension spring ( 1 ) having

a first end, and

a second end;

a damper ( 4 ),

which is disposed inside the extension spring

which has a housing ( 6 ) that is supported on the first end of the extension spring ( 1 ), and

which has a piston rod ( 8 ) that is extended from the housing ( 6 ) and movable over a damping range and directed into the extension spring ( 1 ); and

an operating element ( 5 ),

which comprises an actuating tappet ( 11 ),

which is joined to the second end of the extension spring ( 1 ), and

which is movable over a total range c that includes a no-load range b of the actuating tappet ( 11 ) whereby the actuating tappet ( 11 ) is not in contact with the piston rod ( 8 ) and that includes the damping range a of the piston rod ( 8 ) whereby the actuating tappet ( 11 ) is in contact with the piston rod ( 8 ),

wherein the extension spring strut is longitudinally adjustable,

wherein a first abutment ( 13 ) and a second abutment ( 14 ) are mounted on the first end and second end of the extension spring ( 1 ), with a first holding bush and a second holding bush ( 16 ) being disposed in the first and second abutment ( 13 , 14 ) for adjustment by threads ( 17 , 18 ) that work in opposite directions; and

wherein the damper ( 4 ) bears against one of the first and second holding bushes ( 15 , 16 ) and the actuating tappet ( 11 ) bears against one of the second and first holding bushes ( 15 , 16 ).

8. The extension spring strut according to claim 7 , wherein b>a applies to the damping range a to no-load range b ratio.

9. The extension spring strut according to claim 7 , wherein the actuating tappet ( 11 ) is disposed for displaceable guidance in a guide tube ( 10 ).

10. The extension spring strut according to claim 9 , wherein the guide tube ( 10 ) is coaxially joined to the housing ( 6 ) of the damper ( 4 ).

11. The extension spring strut according to claim 7 , wherein the damper ( 4 ) is a hydraulic damper.

12. An extension spring strut for use in a vehicle, comprising

a helical extension spring ( 1 ) having

a first end, and

a second end;

wherein said extension spring is in a tensioned state between the first end and the second end when said first end and said second end are engaged in said vehicle and said strut is at rest, wherein said extension spring is in linear contraction from said tensioned state when said strut is in operation,

a damper ( 4 ),

which is disposed inside the extension spring

which has a housing ( 6 ) that is supported on the first end of the extension spring ( 1 ) and is filled with a damping fluid, and

which has a damping piston ( 7 ) disposed in the housing ( 6 ); and

which has a piston rod ( 8 ) that is mounted on the damping piston ( 7 ) and extended from the housing ( 6 ) and movable over a damping range a and directed into the extension spring ( 1 ); and

an operating element ( 5 ),

which comprises an actuating tappet ( 11 ),

which is connected with the second end of the extension spring ( 1 ), and

which is movable over a total range c when said extension spring contracts during operation of said strut and that includes the damping range a of the piston rod ( 8 ) and a no-load range b of the actuating tappet ( 11 ).

13. The extension spring strut according to claim 12 , wherein b >a applies to the damping range a to no-load range b ratio.

14. The extension spring strut according to claim 12 , wherein the actuating tappet ( 11 ) is disposed for displaceable guidance in a guide tube ( 10 ).

15. The extension spring strut according to claim 14 , wherein the guide tube ( 10 ) is coaxially joined to the housing ( 6 ) of the damper ( 4 ).

16. The extension spring strut according to claim 12 , wherein the extension spring strut is longitudinally adjustable.

17. The extension spring strut according to claim 12 , wherein the damper ( 4 ) is a hydraulic damper.