Fifth wheel plate assembly for trailer hitch

Claim 1

A fifth wheel plate assembly for connection with the kingpin of a trailer, said assembly comprising a plate having a substantially circular opening in said plate and an entry slot communicating with said circular opening, a coupler jaw supported for turning movement within said circular opening, said coupler jaw including an open end slot normally disposed to be engaged by a kingpin when the kingpin is moving through said entry slot and in alignment with said open end slot in a manner to cause turning movement of said jaw to close said open end slot with the kingpin retained therein, locking notch means formed on the coupler jaw, a locking plunger mounted on said plate for lengthwise movement into and out of engagement with said locking notch means when the latter is aligned therewith and the open end slot is in said closed position, resilient means biasing said locking plunger into engagement with said locking notch means, the improvement comprising: locking and actuating means for retracting said locking plunger from seating engagement with said locking notch means including, an actuating arm connected to said plate and to said locking plunger for manual movement, whereby during said manual movement said locking plunger is in a partially retracted position with respect to said locking notch means against said biasing means, catch means on said plate for engaging said arm in said partially retracted position, said locking notch means including means engageable with said locking plunger during rotation of said jaw to a position wherein said slots are in alignment to completely retract said plunger from said locking notch means and thereby disengaging the same from said catch means; whereupon realignment of said locking notch means with said plunger, said biasing means again urges said plunger in engagement therewith; said catch means having a stop member including disengageable latch and indicating means disposed in one position in the path of horizontal planar movement of said arm when said locking plunger is in seating engagement with said locking notch means, said latch and indicating means including a flap hingedly supported on said plate and in said one position being disposed vertically indicating a locked position of said plunger, said flap being manually hingedly movable from said one position to a substantially horizontal position to permit the path of horizontal planar movement of said arm for moving said plunger to said partially retracted position, said stop member being connected to the underneath side of said plate, said arm being shiftable vertically into engagement with said stop member during said partially retracted position of said plunger, said catch means including a ledge supporting said arm during engagement of said plunger with said locking notch means when said plunger is in the partially retracted position, and means on said locking notch means to completely retract said plunger including first camming means engageable with second camming means on said plunger to move the latter to said completely retracted position whereupon said arm is disengaged from said ledge and drops by gravity from said ledge; and said plunger is biased against said coupler jaw.