Heretic’s fork, Spain or Spanish Netherlands, 17th centuryIron  shaft with a two-pronged fork on both ends. In the centre two loops  with an an iron buckled leather collar. The  prongs of the fork pierced the skin under the chin and over the  breastbone, causing pain and preventing a natural position of the head. A  heretic was thus supposedly forced to look his judge in the eye. It is,  however, more likely that this torture device was used to thoroughly  demoralise the victim.
Found here.
The iron virgin as she was.
From Thumbscrew and Rack by Geo. E. Macdonald.
Via A Journey Round My Skull.