A-Frame
The triangular frame on the implement side that carries two lower pins and one top pin. The tractor's three-point linkage attaches to this frame; draft and lifting forces are distributed from here into the implement body. The height of the triangle and the pin spacing must match the linkage category it will be connected to.
The A-frame is the load-carrying element that spreads force concentrated at a single point into the implement chassis. The two lower pins take the draft load, while the top pin reacts the overturning moment. When the triangle's geometry is distorted the implement sits at an angle relative to the tractor and the depth setting does not hold.
- If you see a crack or an ovalised hole in the A-frame, do not operate the implement under load.
- If there is more than one top pin hole, the hole chosen changes the working angle of the implement.
- If a quick-hitch coupler is to be used, the pin spacing of the A-frame must match the coupler standard.
Electronic retrofit kits have no connection at all with the A-frame; they are fitted on the control side. On the other hand, a system that can be controlled from outside the cab makes your job easier when aligning the A-frame with the tractor's hooks: you can move the linkage by millimetres, seat the frame exactly, then secure the pins.
Context in which this term is used: Converting a tractor hydraulic lever to electronic control