1. In a harvester comprising a main unit having a frame and a harvesting component pivotally mounted thereon for vertical swinging movement between an operative position and an elevated transport position, means for moving said component between said positions and adjusting the operative position of said component with limited float and including linkage operatively connected to said component and comprising in the linkage a load transmitting element, an anchor element fixed to the frame in side-by-side relation to the load transmitting element whereby the load transmitting element moves back and forth alongside said anchor element, a force transmitting abutment member disposed to transmit a lifting force to the load transmitting element in one direction, power means having a predetermined working range connected between the frame and said abutment member for imposing a lifting force through said abutment member to said load transmitting element, and means for interlocking said elements against movement toward said power means comprising transversely registering slots in said elements and a pin positionable through both of said slots, said slots dimensioned and oriented to accommodate insertion for storage of said pin in either slot in either element without bottoming the pin in such slot against the other element at the limit of the working range of the lifting means thereby to prevent damage to the linkage and with the pin interlocking said elements extending through the slots in both elements accommodating movement of said load transmitting element beyond the locking position of the pin with the elements and beyond the working range of the power means.

5. In a crop-harvesting machine a frame, a harvesting component hung thereon adapted to drop off its own weight toward the ground, lifting means operative between the frame and the component for raising the component from a lowered operating position to an upper transport position including a hydraulic ram for actuating said means, and locking means for securing said lifting means in transport position to facilitate removal and application of said ram, said locking means comprising a bracket on the frame having a slot, said lifting means comprising a link swingably mounted on the frame for movement alongside said bracket and having a slot therein transversely alignable with the slot in the bracket, and a pin adapted to be inserted through both slots upon alignment thereof, said slot in the link being elongated in the directions of movement of the link whereby to prevent accidental damage to the link and bracket upon the hydraulic ram being actuated with the pin in locking position, said slot in the link providing lost motion between the link and pin in the direction of movement of said ram and swing link to lift the component.

8. In a farm implement comprising a frame, an implement pivotally mounted thereon and biased groundwardly by its own weight, lifting means operatively connected between the frame and the implement for lifting the latter from a lowered to a raised position and for gradually lowering the implement from raised to lowered position and comprising a ram connected at one end to the frame, an abutment link pivoted to the other end of the ram, a swing link pivotally supported on the frame in the path of movement of the abutment link and supporting the implement load and in contact with the abutment link in opposition to the bias load of the implement, said link having a slot therein elongated generally in the direction of swinging movement of said swing link in raising and lowering the implement, a bracket on the frame having a slot elongated transversely to the slot in the swing link and alignable therewith in certain positions of the implement, and means positionable through the aligned slots for locking the swing link to the bracket against movement lowering the implement whereupon said abutment link is adapted to be separated and disengaged from the swing link to facilitate connection and disconnection of the ram from the abutment link, said slots dimensioned to accommodate movement of the swing link to the limit of lifting movement of the ram while the locking means is disposed in either or both of said slots.

10. A damage-preventing mechanism in a lifting and lowering linkage for an implement wherein said linkage has separable parts, the implement being connected to one part and biasing the same against the other part and power means is connected to the other part and adapted to move the same in opposition to the other part to lift the implement, anchor means adjacent to the one part, and means providing a lost-motion connection between the one part and the anchor means conditionable to accommodate lifting and lowering of the implement via said parts for the full operating range of said power means, said means providing a lost-motion conditionable to limit the movement of the one part with respect to the anchor means in the direction lowering the implement and in such condition accommodating lifting of the implement to the full operating extent of the power means.