Method and member for tightening threaded fasteners, and fixing and tightening device

摘要

This method of tightening a threaded fastener (6) to a predetermined torque comprises steps in which: axial and rotational coupling is begun, by surface shrinking to a tight fit, of the threaded fastener (6) to a tightening member (2) capable of turning the threaded fastener (6) and thereby tightening it, the tightening member (2) and the threaded fastener (6) being able, from an initial coupled configuration between the tightening member and the threaded fastener, to remain rotationally coupled at a rotary drive torque, transmitted by the tightening member to the threaded fastener, that is less than the predetermined tightening torque, and to be rotationally decoupled from each other at a rotary drive torque, transmitted by the tightening member to the threaded fastener, that is equal to the predetermined tightening torque; and from this initial coupled configuration, a rotary movement is applied to the tightening member (2) up to a rotary drive torque, transmitted by the tightening member (2) to the threaded fastener (6), that causes rotational decoupling of the tightening member (2) from the threaded fastener (6).

主权项

1. A combination comprising a tightening member and at least one screw-fastener element, which combination is adapted for securing the at least one screw-fastener element to a mating fastener element with a predetermined tightening torque, the at least one screw-fastener element having a continuous engaging surface that extends continuously along a complete periphery of the at least one screw-fastener element and the tightening member having a corresponding continuous engaging surface that extends continuously along a corresponding complete periphery of the tightening member such that the tightening member is held both axially and in rotation relative to the screw-fastener element by tight-fit surface interference of the continuous engaging surfaces of the tightening member and the at least one screw-fastener element and such that the tightening member and the at least one screw-fastener element rotate with one another as continuously increasing torque is applied to the tightening member which is less than the predetermined torque, the continuous engaging surface of the tightening member including at least one peripheral spline complementary to at least one peripheral spline of the engaging surface of the at least one screw-fastener element, a projecting surface portion of the at least one peripheral spline of the tightening member being in tight-fit surface interference with a projecting surface portion of the at least one peripheral spline of the engaging surface of the at least one screw-fastener element when the tightening member and the at least one screw-fastener element rotate together, wherein the tightening member and the at least one screw-fastener element rotate relative to each other when a torque transmitted by the tightening member to the at least one screw-fastener element reaches the predetermined tightening torque and without destruction of the tightening member, whereby at the predetermined tightening torque, there is a maximum friction force between the projecting surface portion of the at least one peripheral spline of the continuous engaging surface of the tightening member and the at least one screw-fastener element beyond which there is no longer friction drive force between the continuous engaging surfaces of the tightening member and of the at least one screw-fastener element.