Piece of seating furniture

1. A piece of seating furniture comprising:

a base member, on an upper side of which a padded seat surface is provided;

at least one backrest member with a padded backrest surface, which can be positioned in various positions on the upper side of the base member;

a slot structure in the padded seat surface of the base member, which penetrates the padded seat surface; and

a guide member connected to the at least one backrest member which projects through the padded seat surface in an area of the slot structure;

the guide member being fastened in an articulated or movable manner to a fastening surface of the base member by at least one hinge device;

the guide member being attached to the fastening surface so as to be rotatable about a vertical axis of rotation by the at least one hinge device; and

the guide member being attached to the fastening surface so as to be rotatable about a horizontal axis of rotation by the at least one hinge device.

2. The piece of seating furniture according to claim 1 , wherein:

the guide member is attached fixedly to the backrest member such that the guide member and the backrest member are moved in fixed relative position to each other when the guide member is rotated about the horizontal axis of rotation or about the vertical axis of rotation.

3. The piece of seating furniture according to claim 1 , wherein:

the base member has a base plate below the upper side, the at least one hinge device being attached to this base plate.

4. The piece of seating furniture according to claim 1 , wherein:

the slot structure has at least one connection area in which at least three individual slots are brought together.

5. The piece of seating furniture according to claim 4 , wherein:

the slot structure has at least two slots which cross in the at least one connection area, so that at least four individual slots are brought together in the at least one connection area.

6. The piece of seating furniture according to claim 4 , wherein:

the at least one connection area of the slot structure is provided above the at least one hinge device; and

the guide member has a linearly extended first portion which can be brought into a vertical orientation by the at least one hinge device, the linearly extended first portion having a sufficient length such that an end thereof remote from the at least one hinge device extends beyond the padded seat surface of the base member in a vertical orientation.

7. The piece of seating furniture according to claim 1 , wherein:

the at least one guide member is immovably attached to the backrest member.

8. The piece of seating furniture according to claim 1 , wherein:

the upper side of the base member is substantially square.

9. A piece of seating furniture comprising:

a base member having an upper padded seat surface;

a backrest member with a padded backrest surface, the backrest member being able to be positioned in various positions on the upper padded seat surface of the base member;

a slot structure in the upper padded seat surface of the base member, the slot structure penetrating the upper padded seat surface; and

a guide member connected to the backrest member, the guide member projecting through the slot structure in the upper padded seat surface;

the guide member comprising a movable joint system and being fastened to a fastening surface of the base member; and

the movable joint system allowing the guide member to be rotatable about both a vertical axis of rotation and a horizontal axis of rotation at the movable joint system.

10. The piece of seating furniture according to claim 9 , wherein:

the guide member is attached fixedly to the backrest member such that the guide member and the backrest member are moved in fixed relative position to each other when the guide member is rotated about the horizontal axis of rotation or about the vertical axis of rotation.

11. The piece of seating furniture according to claim 9 , wherein:

the base member has a base plate below the upper padded seat surface, the base member having the fastening surface.

12. The piece of seating furniture according to claim 9 , wherein:

the slot structure has an intersection in which at least two non-parallel individual slots are brought together.

13. The piece of seating furniture according to claim 9 , wherein:

the slot structure has at least two slots which cross in a connection area so that at least four individual slots intersect in the connection area.

14. The piece of seating furniture according to claim 13 , wherein:

the connection area of the slot structure is provided above a hinge device; and

the guide member has a linearly extended first portion which can be brought into a vertical orientation by the movable joint system, the linearly extended first portion having a sufficient length such that an end of the linearly extended first portion remote from the movable joint system extends above the upper padded seat surface of the base member in the vertical orientation.

15. The piece of seating furniture according to claim 9 , wherein:

the guide member is immovably attached to the backrest member.

16. The piece of seating furniture according to claim 9 , wherein:

the upper padded seat surface of the base member is substantially square.

17. The piece of seating furniture according to claim 9 , wherein:

the movable joint system includes a first hinge member allowing the guide member to be rotatable about the vertical axis of rotation and a second hinge member allowing the guide member to be rotatable about the horizontal axis of rotation.

18. The piece of seating furniture according to claim 9 , wherein:

the movable joint system is located within the base member.

19. The piece of seating furniture according to claim 1 , wherein:

the at least one hinge device comprises a first hinge member and a second hinge member, the first hinge member allowing the guide member to be rotatable about the vertical axis of rotation and the second hinge member allowing the guide member to be rotatable about the horizontal axis of rotation.