Victorinox

Introduced in 1902 the Shackle, also known as a Bail, was seen on Victorinox knives up until ~1969 at which time it was replaced with the smaller split-ring attachment method. The Alox Soldier between the years of 1963 and 1992 (some 1993), contain a hollow rivet at the end of the knife that was used as an attachment point. A removable Bail could be inserted into this, or a string or lanyard could simply be threaded through. Apparently the knife was never issued to Soldiers with the Bail.

Wenger

Wenger still uses a Bail on their current Standard Issue / Soldat Alox model, however the Cellidor models also had Shackles at around the same time as the Victorinox models, and Wenger also used Bails on some Cellidor models. Exact dates are virtually impossible to tell due to a fire that destroyed much of Wenger's Delemont facility in 1986. Today Wenger knives, other than the 'Standard Issue'' are using a split-ring attachment point system.