1. Tool holder device (10) comprising a stem (1 1 ) and at least one interchangeable head (12) able to fit inside said stem (1 1 ), wherein said stem (1 1 ) comprises a first side (1 12), facing outside said stem (1 1 ) and in the direction of said head (12), and a second side (1 13) perpendicular to said first side (1 12), wherein said stem (1 1 ) comprises a first conical junction seat (1 1 1 ) with said head (12) of a preferably trilobo-conical shape of the concave type, wherein said first conical junction seat (11 1 ) is positioned in corrispondence of said first side (1 12) of said stem (1 1 ) in such a way as to allow a quick connection between said stem (1 1 ) and said head (12), and wherein said device (10) comprises on said second side (1 13) a first and a second screw (20, 21 ), adjacent to each other and respectively for locking and unlocking said head (12) inside said first conical junction seat (11 1 ) of said stem (1 1 ), characterized by the fact that said second unlocking screw (21 ) is in contact with and acts on a chamfer (123) located on said head (12), so that a user, after having previously loosened said first locking screw (20), is able to extract said head (12) from said first conical junction seat (1 1 1 ).

2. Tool holder device (10) as claimed in claim 1 characterized in that said head (12) in turn comprises a second conical junction seat (121 ) with a trilobo-conical shape of the convex type, complementary to said conical junction seat (1 11 ) of said stem (1 1 ).

3. Tool holder device (10) as claimed in claim 1 characterized by the fact that said first and second screws (20, 21 ) are adjacent.

4. Tool holder device (10) as claimed in one of the preceding claims characterized in that said first screw (20) is substantially placed at an edge between said second side (113) and said first side (1 12), and that said second screw (21 ) is placed on the opposite side of said edge, with respect to said first screw (20).

5. Tool holder device (10) as claimed in one of the preceding claims characterized in that said first screw (20) is adapted to lock said second

AMENDED SHEET (ARTICLE 19) conical junction seat (121 ) of said head (12) within said first conical junction seat (1 11 ) of said stem (1 1 ), inserting inside an opening (122) placed in correspondence with said head (12).

6. Tool holder device (10) as claimed in at least one of the preceding claims characterized characterized by the fact that said stem (11 ) has a substantially polyhedral shape, in particular a parallelepiped.

AMENDED SHEET (ARTICLE 19)