Unit for beading tires in tire changing machines or the like

A unit (1) for beading tires in tire changing machines or the like, comprising at least a bearing structure (2) associable with a tire changing machine (A) or the like, at least a supporting element (3) associated with said bearing structure (2) and moving with respect to the rim (C) of a wheel (D) mounted on said tire changing machine (A), a first actuator arrangement (6, 8) for moving said supporting element (3) on said bearing structure (2), and at least a beading tool (4) associated with a free extremity of said supporting element (3), further comprising a second actuator arrangement (12) and a transformation arrangement (13) for transforming the movement generated by said second actuator arrangement (12) in the translation movement of said beading tool (4) along a substantially curvilinear trajectory between a first extreme position, in which said beading tool (4) is substantially retracted with respect to said rim (C), and a second extreme position, in which said beading tool (4) is substantially closer with respect to said rim (C).