Note to King Lear, 1.4.268

King Lear,
Act 1, Scene 4, line 268
Which, like an engine, wrench'd my frame of nature
From the fix'd place:

—I believe the "engine" that Lear has in mind is the torture device known as "the rack," which was built to wrench a person's body ("frame of nature") from its natural shape, its "fix'd place."