Swing Away Guard : Rotating Arm
The two next sketches enable you to draw the arm step by step. Start to define the main axis of the rotating arm then follow the needed dimensions to progress. Lastly round the angles before cutting off.
The apron height is directly related to the sliding cover
thickness and helps for the strengthening of the arm. the front side is slightly less thick and aims to avoid dust and chips jam.
The mount is a strengthened metal angle with a wedged pivot. The spring will probably need some experiments and may be coiled with this method
. All the other parts are related to the planer-jointer and the guard dimensions.