X Axis ( perpendicular application on vertical steel web ) = 10 KN...
Source : SGB Gravlok Spec Sheet, I tried to attach the spec sheet to this post, however, the Document was to large to post...
With regard to the use of check fittings on the perpendicular : personally, I would avoid this practice, electing to Design in an alternative...
ALWAYS USE IN PAIRS lol...
Presco have the loadings for their Gravlocks here:
http://www.presco.co.uk/leaflets/girder_couplers_forged.pdf
Just had a look. I've never came across the swivel versions on my travels. First I've seen it tbh.