摘要 |
The preferred embodiments of the invention disclosed herein relate to a tightening system comprising a wrench for rotating and applying torque to a fastener system, means for developing a signal representative of the torque being applied and means for developing a signal representative of the rotation. A control system is operatively associated with the wrench for determining which of the two signals is increasing faster. If the torque signal is increasing faster than the rotation signal, the control system modifies the rotation signal by increasing it until it corresponds to the torque signal, but cannot decrease the modified rotation signal when the increase of the torque signal is less than the increase of the rotation signal. When the increase of the torque signal decreases relative to the modified rotation signal, the control system develops a decision-making signal which is processed to develop a control signal when a yield point of the fastener system is detected. |