This is an example of a vertical second-class lever.

In the second-class lever design, the arm pivots below the rim.

As such it is a second-class lever.

A second-class lever is where the resistance is between the effort and the fulcrum.

That is, they use a second-class lever, rather than the usual first-class lever.

Both first- and second-class lever designs exist; second-class is by far the most common.

The speed opener is a first-class lever (instead of a second-class lever), as discussed in technique, below.

(First and second-class lever designs exist; first-class is most common and is described here.)

Note that the common first-class lever roller cam brake is generally not convertible to second-class lever cantilever brake types as the pivots are in different locations.

A bow and arrow is a slighty complex version of a second-order lever," said Curt, "with the fulcrum at the center of the bowstave itself, and the force exerted backward at the tips by the pulled bowstring against the stiffness of the bowstave.