Cam lock + square key

According to the current safety norms, the protective shields should not stay in place unless they are locked, the locking elements may not come loose when you open the mesh and the shields must be locked with a tool…a nice set of requirements.

One simple way to tackle the loosening and tooling is the use of locks typically found in electrical cabinets.
And as rusted bolts are annoying, so are also rusted locks…that’s why this one is in AISI 316