what did the TT do to be sure that the little people would not tamper with the time machine or damage it?

The TT took the levers so the little people couldn't tamper with the machine.

Happily then, when it was not too late, I thought of a danger I had hitherto forgotten, and reaching over the bars of the machine I unscrewed the little levers that would set it in motion, and put these in my pocket.