Machine for removing and fitting wheel tyres for vehicles

Machine (1) for removing and fitting wheel tyres for vehicles, comprising:

• at least a bearing structure (2),
• a clamping device (5) of a rim (C) of a wheel (R) for vehicles, associated with said bearing structure (2) and rotatable around a first axis of rotation (X1),
• at least a tool-carrying arm (6) associated movable with said bearing structure (2) and having at least a removing/fitting tool (7) of a tyre (P) from/onto said rim (C), and
• at least an auxiliary arm (8) having at least a bead pressing tool (9, 10) able to facilitate the removing/fitting operations of the tyre (P) from/onto the rim (C) and associated rotatable with said bearing structure (2) around a second axis of rotation (X2) substantially parallel to said first axis of rotation (X1);
• at least a movement device (17) of said auxiliary arm (8) and/or of at least one bead pressing tool (9, 10) along a substantially vertical direction between a raised position and a lowered position;
• wherein said auxiliary arm (8) comprises at least a first small arm (15) and a second small arm (16) rotatable around a third axis of rotation (X3) substantially parallel to said first axis of rotation (X1) and having respective bead pressing tools (9, 10) able to facilitate the removing/fitting operations of the tyre (P) from/onto the rim (C), wherein the distance of said third axis of rotation (X3) with respect to said first axis of rotation (X1) is defined by the following formula:
• 0<d(X1,X3)<r
• where d(X1, X3) indicates said distance of the third axis of rotation (X3) with respect to the first axis of rotation (X1) and r indicates at least a value corresponding to the radius of said wheel (R);
• wherein said automatic positioning apparatus (20) comprises at least an automatic operation device (21) of said movement device (17) operatively connected to said auxiliary arm (8) and able to be automatically activated in correspondence of a predetermined angular position of said auxiliary arm (8) to bring said at least one bead pressing tool (9, 10) from said lowered position to said raised position;
• wherein said auxiliary arm (8) comprises at least a horizontal arm (11, 12) associated rotatable with said bearing structure (2) around said second axis of rotation (X2) and at least a small arm (15, 16) having said at least one bead pressing tool (9, 10) and associated rotatable with said horizontal arm (11, 12) around a third axis of rotation (X3) substantially parallel to said first axis of rotation (X1);
• wherein the machine (1) comprises an automatic positioning apparatus (20) that comprises at least a return element associated with said auxiliary arm (8) and able to bring said auxiliary arm (8) back to said rest position when said at least one bead pressing tool (9, 10) is in the raised position;
• wherein said return element comprises at least an elastic element associated with said auxiliary arm (8).