Automatic dynamic joint tensioning system

A system for automatically adjusting a fastener screw of a pivot joint between first and second parts of a pair of scissors, each part including a respective blade and handle, the system comprising:

• a first fixture configured to engage the handle of the first part of the pair of scissors;
• a second fixture configured to engage and move the handle of the second part of the pair of scissors relative to the first part about the pivot joint;
• a driver configured to adjust the fastener screw to provide a desired resistance to relative movement between the first and second parts;
• a position encoder connected to the first and second fixtures to generate a position signal indicative of the position of the second part relative to the first part;
• a torque transducer connected to the first and second fixtures to generate a torque signal indicative of the resistance to relative movement between the first and second parts;
• a controller having inputs operatively connected to the position encoder and to the torque transducer and an output operatively connected to the driver, the controller being responsive to the position signal and to the torque signal, the controller controlling the driver.

A method for automatically adjusting a fastener of a pivot joint between first and second parts of an assembly, comprising the steps of:

• moving the second part relative to the first part about the pivot joint while monitoring the relative angular displacement of the parts;
• driving the fastener while monitoring the torque required to move the second part relative to the first part;
• and
• adjusting the tightness of the fastener to achieve a monitored torque that is within predetermined limits.

A method for automatically adjusting a fastener screw of a pivot joint between first and second parts of a pair of scissors, comprising the steps of:

• moving the second part relative to the first part about the pivot joint while monitoring the relative angular displacement of the parts;
• driving the fastener screw while monitoring the torque required to move the second part relative to the first part;
• and
• adjusting the tightness of the fastener screw to achieve a monitored torque that is within predetermined limits.