A lever was a tool used to enable one to lift heavy objects.
In 2153, Trip Tucker and Kessick used levers to open a hatch to a plasma conduit during their escape from a trellium-D mining facility. (ENT: "The Xindi")
In 2265, Gary Mitchell amused himself by, among other things, causing levers on the bridge of the USS Enterprise to move seemingly by themselves. (TOS: "Where No Man Has Gone Before")
In 2370, when the Barkon IV blacksmith Skoran's anvil collapsed on his apprentice's leg, he suggested using a lever to raise it. (TNG: "Thine Own Self")
The Delta Flyer used of several levers and knobs rather than touch screen technology to operate. Tom Paris preferred it that way, saying he liked being able to feel what he was doing. (VOY: "Extreme Risk")