Adjustable rotation radius articulated joint for gym machines and knee tutors

Adjustable rotation radius articulated joint for gym machines and knee tutors formed by two or more mechanical parts such as plates (1, 2) placed side by side;

• at least one of these plates (1, 2) features a linear central opening (2.2, 9) which is at a right angle to the rotation surfaces of the plates and developed lengthwise;
• the plate (2) features a peripheral opening (2.3, 10) in form of an arc for the first 15°-45°;
• one plate (1) feature two pins (1.2, 1.3) at the right angles to the rotation surfaces of the plates that feature at the distal end constraints as plate (1.4, 1.5, 8) which prevent the two plates from separating;
• the central pin (1.2) is inserted in the above mentioned linear central opening (2.2, 9);
• the peripheral pin (1.3) is placed in the peripheral opening (2.3, 10);
• the joint is characterised by the fact that the above mentioned plate (2) can be substituted by a group composed by a plate (3) and segments of plates (4, 5, 6, 7) arranged in pairs when one pair (4, 5) is placed side by side to the other pair (6, 7);
• in each pair one segments of plates (4, 7) is put on the top of the other segments of plates (5, 6);
• the plate (2) or one of the segment of plate (6), features a mobile arm (2.1, 6.1), and the plate (1) features an arm (1.1) which can either be mobile or be locked to the gym machine;
• the above mentioned central opening (2.2, 9) is located on the plate (2) or on the segment of plate (6) and begins from a central point (2.4, 9.1) located in the centre of the plate (2) or segment of plate (6) and then proceeds towards the mobile arm (2.1, 6.1) along a radius (a) whose direction coincides with the longitudinal axis of symmetry of the mobile arm itself (2.1, 6.1);
• the above mentioned peripheral opening (2.3, 10) is located on the plate (2) or on two segments of plate (6, 7) positioned one on top of the other, one end of this peripheral opening (2.3, 10) is located at the distance “l” from the above mentioned central point (2.4, 9.1), which lies on a radius (b);
• radius (b) is at a right angle to radius (a) and on the same plane, while the other end is located at 1350 to radius (b);
• this peripheral opening (2.3, 10) has a specific shape:
• initially, in respect to radius (b) for the first 15°-45°, it has a circular form, whose center coincides with the above mentioned central point (2.4, 9.1) with a radius equal to “l”;
• subsequently, for the remaining 90°-120°, it form a spiral which develops towards the central point (2.4, 9.1);
• the sequence of points forming the longitudinal axis of this spiral is derived from the sequence of points of one end of a segment of length “l”, the other end moves along the longitudinal axis of the central opening (2.2, 9) towards the mobile arm (2.1, 6.1);
• a radius (d) divides the peripheral opening (2.3, 10) in two parts:
• one circular part (10.1) and one spiral part (10.2);
• if two segments of plates (6, 7) placed one on the top of the other, are being used, one segment of plate (6) will feature the circular part (10.1) of the opening (2.3, 10), while the other segment of plate (7) will feature the spiral part (10.2) of the peripheral opening (2.3, 10) itself;
• a fulcrum (11) is located on radius (d);
• the above mentioned pins (1.2, 1.3) are located at a distance equal to “l” and the central pin (1.2) can also be the ending of a driver shaft;
• the plates or segments of plates rotate around an axis (c) which passes through the user's femoral condyles;
• these plates or segments of plates can move freely onto one another when no plate is locked to a fixed structure, as is the case with knee tutors and passive gymnastics machines;
• alternatively, the plate (1) can be locked to the machine by means of a fastener such as an arm (1.1), and the other plate (2) or group of plate (3) and segments of plates ( 4, 5, 6, 7) rotate on the plate (1) itself, as is the case with the leg extension and leg curl machines where the load is fastened onto the mobile load arm (6.1), or the plate (2) or the group of plate (3) and segments of plates (4, 5, 6, 7) can be fastened to the machine and the plate (1) is left free to rotate on the latter as is the case with the leg extension and leg curl machines where the load is fastened onto the pin of the joint.