An arm to be mounted by one of its faces, referred to as a mounting face (Fm), in a hinge connection about a hinge axis, to a frame of eyeglasses, so as to be able to pivot between a folded position and an unfolded position, the arm comprising: - a first segment provided with a first housing opening through the mounting face (Fm) and through a first face of the first segment opposite to the mounting face (Fm); - a second segment comprising a second face through which a second housing opens, the first and the second face being of complementary shapes so as to allow them to be interlocked; the arm is also provided with a hinge element fastened to the second segment in the second housing and which passes through the first housing to leave one of its ends, referred to as an attachment end (Ea), to open, provided with a charnier for fastening the arm to an endpiece of a frame of eyeglasses, the hinge element being configured to exert a spring force holding, by default, the first and second faces interlocked, and allowing articulation of the second segment with respect to the first segment when a force is exerted on the second segment, the profile of the first face in a cutaway plane perpendicular to the hinge axis is configured so as to retain interlocking of the first and the second face when a force is exerted on the second segment in a plane perpendicular to the hinge axis in order to fold the arm, the first segment comprises an abutment formed by a tab projecting with respect to the first face and in the continuity of an inner face (Fi) of said first segment, the inner face (Fi) being for facing a main framework of the frame of eyeglasses when the arm is folded back, the tab is configured so as to retain interlocking of the first and second faces when a force is exerted on said arm in a plane perpendicular to the hinge axis in order to fold it, the hinge element comprises a rod that extends from the attachment end (Ea) to an end, referred to as a terminal end, a spring coaxially mounted to a section of the rod housed in the second housing, the hinge element further comprises, being arranged on either side of the spring, and in the order from the attachment end (Ea) to the terminal end (Et), a threaded bushing and an abutment bushing for the spring, the threaded bushing and the abutment bushing being arranged to hold the spring in compression, the threaded bush is in slide connection with the rod and is screwed into the second housing. - a first segment provided with a first housing opening through the mounting face (Fm) and through a first face of the first segment opposite to the mounting face (Fm); - a second segment comprising a second face through which a second housing opens, the first and the second face being of complementary shapes so as to allow them to be interlocked; the arm is also provided with a hinge element fastened to the second segment in the second housing and which passes through the first housing to leave one of its ends, referred to as an attachment end (Ea), to open, provided with a charnier for fastening the arm to an endpiece of a frame of eyeglasses, the hinge element being configured to exert a spring force holding, by default, the first and second faces interlocked, and allowing articulation of the second segment with respect to the first segment when a force is exerted on the second segment, the profile of the first face in a cutaway plane perpendicular to the hinge axis is configured so as to retain interlocking of the first and the second face when a force is exerted on the second segment in a plane perpendicular to the hinge axis in order to fold the arm, the first segment comprises an abutment formed by a tab projecting with respect to the first face and in the continuity of an inner face (Fi) of said first segment, the inner face (Fi) being for facing a main framework of the frame of eyeglasses when the arm is folded back, the tab is configured so as to retain interlocking of the first and second faces when a force is exerted on said arm in a plane perpendicular to the hinge axis in order to fold it, the hinge element comprises a rod that extends from the attachment end (Ea) to an end, referred to as a terminal end, a spring coaxially mounted to a section of the rod housed in the second housing, the hinge element further comprises, being arranged on either side of the spring, and in the order from the attachment end (Ea) to the terminal end (Et), a threaded bushing and an abutment bushing for the spring, the threaded bushing and the abutment bushing being arranged to hold the spring in compression, the threaded bush is in slide connection with the rod and is screwed into the second housing.