It uses a 3000lb winch motor. About 1400kg of pull on a flexible 5mm dyneema cord. This then has a pulley system multiplying the force by 4 times. The jaw is part of a lever which further multiplies the force by about 30%. The motor is running on a slightly higher voltage than normal too.

My first attempt used 2 ultra strong carbon steel crow bars to deliver the force to the 'teeth'. But the system was bending these bars at the same time. So I've had to beef up the thickness of the steel used. So the crow bars are no longer in use.
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