Drive shaft coupling mechanism with safety latch

Claim 1

A drive shaft coupling mechanism particularly for coupling the driven shaft of an agricultural implement to the power takeoff shaft of a tractor comprising: a driving and a driven member, one of said members being a coupling sleeve defining a longitudinal axis and having radial apertures therein and the other of said members being axially engageable with and disengageable from said coupling sleeve and having an annular groove therein; means interposed between said driving and driven members for effecting torque transmission therebetween when said members are axially engaged; locking elements radially movable within said radial apertures engageable within said annular groove for axially locking said members in torque transmitting engagement; a locking sleeve axially movable on said coupling sleeve to a first axial position locking said locking elements in engagement within said annular groove and to a second axial position allowing said locking elements to move within said radial apertures out of engagement with said annular grooves; spring latching means latching said locking sleeve in said second axial position, said latching means being released by radial movement of said locking elements within said radial apertures caused by engagement thereof with said other member when said other member is inserted into said coupling sleeve; and stop means within said radial apertures limiting the radially innermost position of said locking elements when said driving and driven members are disengaged; said locking elements being held within said annular groove when said driving and driven members are in the engaged position at a radial position which is a greater distance from said longitudinal axis of said coupling sleeve than said radially innermost position when said driving and driven members are disengaged.