Proportional torque shaft clutch assembly

A system for securing a cam of a locking mechanism to a rotatable shaft, comprising:

• a cam for actuating a locking mechanism;
• a proportional clutch comprising:
• a sleeve body having a distal end affixed to a face of the cam and a sleeve bore comprising:
• a tapered sleeve journal adjacent the cam;
• and
• a sleeve screw portion with internal threads opposite the sleeve journal;
• a threaded collet inserted at least partially within the sleeve bore having a collet bore and an outer surface comprising:
• tapered collet journal having an axial split extending through a distal end of the tapered collet journal, said tapered collet journal abutting the sleeve journal;
• a collet nut opposite the collet journal external to and extending outwardly from a proximal end of the sleeve bore;
• and
• a collet screw portion with external threads between the collet nut and the collet journal and engaged with the sleeve screw portion;
• and
• a rotatable shaft secured within the collet bore with a break-away torque proportional to an assembly torque applied to the collet nut, and
• wherein a drive torque applied to the shaft that is less than the break-away torque causes the cam to rotate with the shaft, and a drive torque that is greater than the break-away torque causes the shaft to spin within the collet bore.

A method for securing a cam of a locking mechanism to a rotatable shaft, comprising:

• affixing a distal end of a sleeve body to a face of the cam, the sleeve body having a sleeve bore including:
• a tapered sleeve journal;
• and
• a sleeve screw portion with internal threads opposite the sleeve journal;
• installing a collet into the sleeve bore, the collet having a collet nut being external to and extending outwardly from a proximal end of the sleeve bore, a collet bore, and an outer surface including:
• tapered collet journal having an axial split extending through a distal end of the tapered collet journal, said tapered collet journal abutting the sleeve journal;
• and
• a collet screw portion with external threads engaged with the sleeve screw portion;
• inserting a rotatable shaft into the collet bore;
• and
• applying an assembly torque to the collet nut and securing the collet to the sleeve body and the rotatable shaft to the collet with a break-away torque proportional to the assembly torque,
• wherein a drive torque applied to the shaft that is less than the break-away torque causes the cam to rotate with the shaft, and a drive torque that is greater than the break-away torque causes the shaft to spin within the collet bore.