Latch mechanism for lateral transport center-pivot mower

An agricultural machine, comprising:

• a trail frame;
• a wheel arm pivotably attached to said trail frame;
• a field wheel mounted on said wheel arm;
• a tongue pivotably mounted on said trail frame, said trail frame being pivotal relative to said tongue, or vice versa, between a field position and a transport position;
• and
• a latch mechanism for releasably securing said trail frame to said tongue, said latch mechanism comprising:
• (i) a catch mounted on said trail frame for pivoting motion about a fulcrum;
• (ii) a receiver mounted on said tongue, said catch being engageable with said receiver;
• (iii) a spring acting between said catch and said trail frame on a first side of said fulcrum for biasing said catch into engagement with said receiver;
• and
• (iv) a rigid link acting between said wheel arm and said catch on a second side of said fulcrum opposite to said first side;
• wherein:
• pivoting motion of said wheel arm moving said field wheel away from said trail frame causes movement of said rigid link, and, once a pre-defined lost travel motion is overcome, continued movement of said rigid link causes pivoting of said catch about said fulcrum and disengagement of said catch from said receiver.