Mandrel (1, 100) for gripping an object, of the type comprising: • a mandrel body provided with: - a central hole which extends along a longitudinal axis and which is provided with an inlet mouth for the insertion of at least a part of said object; - at least two seats which extend radially and in angular directions different from each other starting from said longitudinal axis of said central hole; • a gripping assembly comprising: - at least two gripping clamps with substantially longitudinal extension, each of said gripping clamps being placed in one of said seats; - a supporting element positioned in said central hole on the opposite side of said inlet mouth, said supporting element being configured to slide along said central hole according to said longitudinal axis, each of said gripping clamps being operatively connected to said supporting element at the level of a first end thereof by means of a first connecting rod characterized in that each of said gripping clamps is operatively connected to the internal walls (4a, 4b) of said seats by means of a second connecting rod and a third connecting rod, so that the rectilinear movement of said supporting element causes the rigid translation of each of said gripping clamps with respect to said mandrel body between a position in which said object is locked and a position in which it is released or vice versa, each one of said second connecting rod and third connecting rod being defined by means of two small plates (9a, 9b, 10a, 10b) inserted on opposite sides between said gripping clamp and one of said walls (4a, 4b) of said seat, so that said plates (9a, 9b, 10a, 10b) interact with said walls (4a, 4b) of said seat and the side walls (6c, 6d) of said gripping clamp during said rigid translation. • a mandrel body provided with: - a central hole which extends along a longitudinal axis and which is provided with an inlet mouth for the insertion of at least a part of said object; - at least two seats which extend radially and in angular directions different from each other starting from said longitudinal axis of said central hole; - a central hole which extends along a longitudinal axis and which is provided with an inlet mouth for the insertion of at least a part of said object; - at least two seats which extend radially and in angular directions different from each other starting from said longitudinal axis of said central hole; • a gripping assembly comprising: - at least two gripping clamps with substantially longitudinal extension, each of said gripping clamps being placed in one of said seats; - a supporting element positioned in said central hole on the opposite side of said inlet mouth, said supporting element being configured to slide along said central hole according to said longitudinal axis, each of said gripping clamps being operatively connected to said supporting element at the level of a first end thereof by means of a first connecting rod characterized in that each of said gripping clamps is operatively connected to the internal walls (4a, 4b) of said seats by means of a second connecting rod and a third connecting rod, so that the rectilinear movement of said supporting element causes the rigid translation of each of said gripping clamps with respect to said mandrel body between a position in which said object is locked and a position in which it is released or vice versa, each one of said second connecting rod and third connecting rod being defined by means of two small plates (9a, 9b, 10a, 10b) inserted on opposite sides between said gripping clamp and one of said walls (4a, 4b) of said seat, so that said plates (9a, 9b, 10a, 10b) interact with said walls (4a, 4b) of said seat and the side walls (6c, 6d) of said gripping clamp during said rigid translation. - at least two gripping clamps with substantially longitudinal extension, each of said gripping clamps being placed in one of said seats; - a supporting element positioned in said central hole on the opposite side of said inlet mouth, said supporting element being configured to slide along said central hole according to said longitudinal axis, each of said gripping clamps being operatively connected to said supporting element at the level of a first end thereof by means of a first connecting rod