Attached to the lower car were two helically threaded vertical rollers, working within the hollow guides.
This piece curves laterally and has a helically sloped top surface.
"spiral-shaped," 1590s, from Latin helicem (see helix) + -al (1).
helical hel·i·cal (hěl'ĭ-kəl, hē'lĭ-)adj.
Of or having the shape of a helix; spiral.
Having a shape approximating that of a helix.