Finnegan, Henderson, Farabow, Garrett & Dunner
Coupler for connecting trailer to tractor
 A coupler for connecting a trailer to a tractor includes a main plate having a top surface and a bottom surface and formed with an oil groove on the top surface for a lubricant to flow therethrough, a pair of king pin locking jaws secured to the bottom surface of the main plate for pivotal movement in a horizontal plane to cooperate with each other to releasably hold a king pin therebetween, and a locking member located on the bottom surface of the main plate for sliding movement in which it is brought into and out of engagement with the jaws, to be inserted in a space defined by heads of the jaws when the king pin is held between the jaws to keep the jaws from pivotally moving. The locking member is formed with an oil sump located on a top surface thereof, and oil passages extending from the oil sump to an outer periphery of the locking member, and the main plate is formed with a through hole extending from a position in which it communicates with the oil groove on the top surface of the main plate to the oil sump on the top surface of the locking member. 
Hitachi Metals, Ltd.
Y B
Y10T B62D
additional inventional
Tadao Takashi
Otsuka Hattori