Parallel jaw pliers where one jaw slides on a slightly arc shaped guide connected to the second jaw, and both jaws are connected by pivots to a primary "pliers" type crossed handle. A cam face on one of the "primary" jaws forces the arc shaped guide tight against the "moving" jaw.
Compare to King's earlier patent no. 1,438,442. A "KING JOHNSON PLIER" marked with the Dec. 12, 1922 patent date actually resembles the 2nd form described in the current patent.