Stan - springs have a known restoring force and the force a
spring exerts is proportional to how much its compressed/expanded. The handle on a generic large-scale
torque wrench is calibrated to compress the spring a certain amount to get a known force. This main spring pushes on some sort of ramp mechanism. As you apply torque the drive is attached to the ramp that applies the force (from the torque) to the spring. At some point the force applied by the ramp is greater than the spring so the ramp is allowed to move and when it does it releases from the drive so the drive can freewheel.
Then it checks to make sure you are using the correct torque sequence on the part and starts screaming madly if you aren't. Ok, made that part up.
Aren't all the small torque wrenches the deflection kind? It would seem that a locking/release mechanism would be very sensitive to
friction at a small scale.
Cliff
