I'm looking for the common name(s) or other unique information of a 2 DoF pendulum joint that has one rod that pivots about one axis, connected to a fork that pivots about the orthogonal axis, which mounts to a fixed frame. The main rod extends all the way through the joint. Moving the rod in the x/y direction above the joint gives inverted movement on the opposite side.

Below is the best example of such a joint I could find. Here the rod appears to be in two parts (threaded rod on top, black plastic below), but they move as one piece.


  • 2
    $\begingroup$ A universal joint? $\endgroup$
    – r13
    Oct 9, 2021 at 1:07
  • $\begingroup$ @philsweet why don't you turn that into an answer? $\endgroup$
    – NMech
    Oct 9, 2021 at 6:40

1 Answer 1


These joints are called gimbals. The main idea is that the pivots are nested. There is an outer pivot, and the frame inside contains another pivot, and so on.

A gimbal is a pivoted support that permits rotation of an object about an axis. A set of three gimbals, one mounted on the other with orthogonal pivot axes, may be used to allow an object mounted on the innermost gimbal to remain independent of the rotation of its support (e.g. vertical in the first animation). For example, on a ship, the gyroscopes, shipboard compasses, stoves, and even drink holders typically use gimbals to keep them upright with respect to the horizon despite the ship's pitching and rolling.


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