Need Torque Sensor

[jjellin]

My company builds a machine that takes a small door (1 ft x 1 ft X 1 in thk) off of a small container (1 ft cube). The door has two key holes that have to be turned 90 degrees to unlock the door for removal.

The manufacturer of the container has asked us to add a torque sensor to measure the actual torque (I'm assuming peak torque) required when turning the locks. I need to add a torque sensor in-line with our key mechanism. We have a step motor and gearbox going direct to one key, and a belt connecting to the other key. Torque is at max 15 N-m per key. The 90 degree turn happens in about 1 second, and takes place once every 5 minutes.

Can anyone suggest a reliable low cost solution, for measuring and outputing peak torque?

Thanks,
Jason

 

[OperaHouse]

I worked on a bottle capping machine and the motor gear drive was just put in a spring collar with a prox sensor to detect a certain rotation that gave a known torque. If you can work out the indexing problem, the stepper motor should be very consistant at cogging/torque limiting by the amount of current supplied. Steppers are a love hate relationship.

 

[skills]

My favorite line of torque transducers come from tranducer techniques and I think the url is

http://www.transducertechniques.com

.