Hallet, Davis & Co. Upright

Instead of the usual bridge pins, these pianos had agraffes screwed into the bridges to both align the strings and set the bearing. In order to try to balance out the down bearing, the holes in the agraffes were positioned in such a way as to have alternating downward pressure and lift, as seen in these pictures of a grand with the same type arrangement. Sohmer & Co. invented a variation on this idea.