Removable assembly for a skateboard

1. A removable assembly for converting a skateboard formed by a board, a front wheel unit and a rear wheel unit, into a surfskate, the removable assembly comprising:

a base piece ( 1 ) configured for the fixing thereof to the board ( 40 ) of the skateboard;

an upper piece ( 7 ) configured for the fixing thereof in a removable manner to the front wheel unit ( 36 ), and

a torsion spring ( 6 ) arranged between the base piece ( 1 ) and the upper piece ( 7 ); where the base piece ( 1 ) is coupled to the upper piece ( 7 ) such that they can rotate with respect to each other; and where the torsion spring ( 6 ) exerts a force aimed at causing both pieces ( 1 , 7 ) to regain a neutral position corresponding to a rectilinear displacement of the skateboard and where when the removable assembly is attached to the board and the front wheel unit attached to the upper piece ( 7 ), a first distance between the board ( 40 ) and the front wheel unit is increased as compared to when the front wheel unit is attached directly to the board ( 40 ), wherein

a second distance between the front wheel unit and the rear wheel unit of the skateboard is unchanged when the removable assembly is disposed between the board and the front wheel unit.

2. The assembly according to claim 1 , wherein the torsion spring ( 6 ) is housed in an essentially cylindrical cavity formed between a first flange ( 50 ) of the base piece ( 1 ) and a second flange ( 51 ) of the upper piece ( 7 ) which fits into the interior of said first flange such that the torsion spring ( 6 ) is fully protected from the exterior in order to prevent the entry of dirt or foreign elements which may affect the behavior thereof.

3. An assembly according to claim 2 which comprises at least one fixing washer ( 65 ′, 65 ″) which is internally fixed to one of the pieces ( 1 , 7 ) through an area of the housing cavity of the torsion spring ( 6 ) by means of two fixing screws ( 67 ) which pass through two fixing holes ( 68 ) situated in said at least one fixing washer ( 65 ′, 65 ″) which also comprises at least two insertion holes ( 66 ) of different diameters which can receive a pin of the torsion spring ( 6 ).

4. The assembly according to claim 1 , wherein a first pin of the torsion spring ( 6 ) is coupled to a first hole ( 14 ) of the base piece ( 1 ) and a second pin of the torsion spring ( 6 ) is coupled to a second hole ( 28 ) of the upper piece ( 7 ).

5. The assembly according to claim 4 , wherein the base piece ( 1 ) comprises an auxiliary hole ( 13 ) perpendicular to the first hole ( 14 ) for the fixing of the first pin of the torsion spring ( 6 ) and the upper piece ( 7 ) comprises an auxiliary hole ( 27 ) perpendicular to the second hole ( 28 ) for the fixing of the second pin of the torsion spring ( 6 ).

6. The assembly according to claim 1 , wherein the base piece ( 1 ) comprises a stop ( 18 ) which cooperates with another stop ( 30 ) of the upper piece ( 7 ) to limit the rotational angle between the base piece ( 1 ) and the upper piece ( 7 ).

7. The assembly according to claim 6 , wherein the stop ( 18 ) of the base piece ( 1 ) and the stop ( 30 ) of the upper piece ( 7 ) are arranged such that they allow a rotation of between 40° and 50° to each side of the neutral position.

8. The assembly according to claim 1 , wherein the rotary coupling between the base piece ( 1 ) and the upper piece ( 7 ) comprises a lower axial bearing ( 4 ) situated between the base piece ( 1 ) and the upper piece ( 7 ), an upper axial bearing ( 10 ) situated between the upper piece ( 7 ) and a single locking nut ( 11 ) of the assembly, and a bolt ( 2 ) which passes through the base piece ( 1 ), the lower axial bearing ( 4 ), the torsion spring ( 6 ), the upper piece ( 7 ) and the upper axial bearing ( 10 ), the upper piece ( 7 ) rotating in relation to the base piece ( 1 ) around said bolt ( 2 ).

9. The assembly according to claim 8 , wherein the bolt ( 2 ) is fixed to the base piece ( 1 ) by means of screwing.

10. The assembly according to claim 1 , wherein the upper piece ( 7 ) comprises a flat surface ( 25 ) intended for the fixing of the wheel unit ( 36 ).

11. The assembly according to claim 10 , wherein the flat surface ( 25 ) comprises holes ( 24 ) for the fixing of the wheel unit ( 36 ).

12. The assembly according to claim 1 , wherein the base piece ( 1 ) comprises a flat surface ( 23 ) intended for the fixing of the board ( 40 ).

13. The assembly according to claim 12 , wherein the flat surface ( 23 ) comprises holes ( 21 ) for the fixing of the board ( 40 ).

14. The assembly according to claim 1 , comprising a rotation-limiting element ( 61 ) which comprises a coupling recess ( 63 ) which can be coupled to a stop ( 30 ) of the upper piece ( 7 ) and fixed to the latter such that it reduces the permitted rotation between the upper piece ( 7 ) and the base piece ( 1 ).

15. The assembly according to claim 1 , which comprises locking means ( 60 ) which prevent the rotation between the upper piece ( 7 ) and the base piece ( 1 ).

16. A removable assembly for converting a skateboard formed by a board, a front wheel unit and a rear wheel unit, into a surfskate, the removable assembly comprising:

a base piece ( 1 ) configured for the fixing thereof to the board ( 40 ) of the skateboard;

an upper piece ( 7 ) configured for the fixing thereof in a removable manner to the front wheel unit ( 36 ), and

a torsion spring ( 6 ) arranged between the base piece ( 1 ) and the upper piece ( 7 ); where the base piece ( 1 ) is coupled to the upper piece ( 7 ) such that they can rotate with respect to each other; and where the torsion spring ( 6 ) exerts a force aimed at causing both pieces ( 1 , 7 ) to regain a neutral position corresponding to a rectilinear displacement of the skateboard and where when the removable assembly is attached to the board and the front wheel unit attached to the upper piece ( 7 ), the distance between the board ( 40 ) and the front wheel unit is increased as compared to when the front wheel unit is attached directly to the board ( 40 ), wherein

the upper piece ( 7 ) includes a flat surface ( 25 ) having the front wheel unit of the skateboard affixed there to when the removable assembly is used on the board ( 40 );

a first pin of the torsion spring ( 6 ) is coupled to a first hole ( 14 ) of the base piece ( 1 ) and a second pin of the torsion spring ( 6 ) is coupled to a second hole ( 28 ) of the upper piece ( 7 ); and

the base piece ( 1 ) comprises an auxiliary hole ( 13 ) perpendicular to the first hole ( 14 ) for the fixing of the first pin of the torsion spring ( 6 ) and the upper piece ( 7 ) comprises an auxiliary hole ( 27 ) perpendicular to the second hole ( 28 ) for the fixing of the second pin of the torsion spring ( 6 ).

17. The assembly according to claim 16 , wherein the torsion spring ( 6 ) is housed in an essentially cylindrical cavity formed between a first flange ( 50 ) of the base piece ( 1 ) and a second flange ( 51 ) of the upper piece ( 7 ) which fits into the interior of said first flange such that the torsion spring ( 6 ) is fully protected from the exterior in order to prevent the entry of dirt or foreign elements which may affect the behavior thereof.

18. An assembly according to claim 17 , further comprising at least one fixing washer ( 65 ′, 65 ″) which is internally fixed to one of the pieces ( 1 , 7 ) through an area of the housing cavity of the torsion spring ( 6 ) by means of two fixing screws ( 67 ) which pass through two fixing holes ( 68 ) situated in said at least one fixing washer ( 65 ′, 65 ″) which also comprises at least two insertion holes ( 66 ) of different diameters which can receive a pin of the torsion spring ( 6 ).

19. The assembly according to claim 16 , wherein the base piece ( 1 ) comprises a stop ( 18 ) which cooperates with another stop ( 30 ) of the upper piece ( 7 ) to limit the rotational angle between the base piece ( 1 ) and the upper piece ( 7 ).