Trip mechanism

A trip mechanism adapted to allow deflection of a ground working tool, said mechanism comprising a shank adapted to be connected to said ground working tool, a support frame adapted to support said shank and ground working tool, a parallel-type deflection linkage comprising an upper arm, a lower arm parallel to said upper arm and acting to support said shank, a forward arm and a rearward arm parallel to said forward arm, said forward and rearward arms being respectively connected to said upper and lower arms to allow rotational movement relative thereto about respective upper and lower axes, said first and second links being pivotally connected together by adjacent ends thereof, said detent linkage being operatively connected to said deflection linkage to hold said deflection linkage in an undeflected position and to allow movement of said deflection linkage when a predetermined load on said ground working tool is exceeded, said first link of said detent linkage being mounted for rotational movement about said lower axis of said forward arm and said second link of said detent linkage being mounted for rotational movement about said upper axis of said rearward arm, a means for adjusting the position of said centering axis of said detent linkage towards and away from a dead center position and on one side of the centering axis, said means being mounted on one of said links and adapted to act on the other of said links, first spring means adapted to return said deflection linkage to said undeflected position after said predetermined load is no longer exceeded, said spring means being mounted between said upper and lower arms, and second spring means to return said detent linkage to its position before movement of said deflection linkage said second spring means being mounted between said detent linkage and said upper arm.