LSJ s.v. khlw/neion [sic] I: a device for drawing water. Defined with the Suda's spelling khlo/neion in ps.-Zonaras, Gennadius Scholarius' Grammar, the Etymologicum Gudianum and the Etymologicum Magnum. In ps.-Zonaras: "But khlo/neion is a crane: Spelled with a short (omicron) and a diphthong (ei). ... a piece of wood tilting backwards and forwards."
The lexica contrast their khlo/neion with khlw/nion "stallion" (Herodian, Partitions p. 65 Boissonade; ps.-Zonaras, Gennadius Scholarius, the Etymologicum Magnum, kappa 1517) or "burned by the gadfly = sexually excited" (Etymologicum Gudianum). The word is not attested in that meaning, but both senses are derived from kh/lwn: LSJ s.v. I "swipe, swing-beam" (as here), LSJ s.v. II "he-ass (Archilochus), stallion (lexica)" (kappa 1516).
Even if the "stallion" meaning of khlw/n[e]ion ever existed, the spelling distinction is probably artificial. Our attested texts use khlw/neion and khlw/nion to mean "swing-beam" (in gardening, or sieges): khlw/nion: Apollodorus of Damascus, Poliorcetica p. 162 Wescher; Apollonius, Homeric Lexicon s.v. kh=la, Hesychius s.v. khlw/nia; khlw/neion: Aristophanes fr. 679 Edmonds, Pollux 7.143, Hesychius s.v., Aristotle, Mechanica 857a, 857b, Menander, Dyscolus 536, Aeneas Tacticus 39.7.