Can someone help me identify what type of towed lawn aerator this item is part of? POssibly part of a Westfield?

http://s419.photobucket.com/albums/p...t=P1020650.jpg

http://s419.photobucket.com/albums/p...t=P1020651.jpg

I acquired two of these (one a sliter and the other a spiker and they clearly attach to something, but I dont know what .

They are very heavy and are 40" accross. They came with an AGRI FAB de thatcher but they definately do not fit on this (unless I am missing some parts )

Thanks John