The section we are referring to is E-B, at the point E the joint is fixed to the base of the boom, this allows for the section to move with the boom. At this point, B, their will still be an upward, lateral and resultant force. The member E-B is 2.121m long, and will be made with commercially available square or channel section. The cross-member with have an upper and mid section and a lower section which will be a roller that will be against the mast.
The bracket has four 15.00mm holes which bolt it to a point on the boom itself. The bracket has two vertical section with three 15.00mm holes drilled into it. Between these sections fit the upper span bracket.
The upper span bracket attaches the boom bracket to the mid span. It has three holes drilled to match the boom bracket. It also sets the change in angle for the span from 90deg to 45deg. To the rear of this bracket is a plate that attaches to the mid-span. This span a simply C-section cut to the right length.
The C-section is fixed at the upper end however at the lower end it has a 15.0mm bolt hole. This hole allows for the bolt to be adjusted. The bolt is also attached to a roller at the very end, a roller that rests on the trunnion rest. The bolt is used so as to be able to adjust the length that it projects from the span, this varies the tension of the entire assembly, but most importantly is helps with rotation while still offering support and being load bearing.
Now on the mast will be a roller/trunnion rest, this will allow the roller and cross-member to rest but still rotate. This rest will support the forces along E-B. From calculation from the free body diagram we know the the forces acting on the member specifically the forces acting along the angle of the member. The rest will be bolted to the mast with two bolts each perpendicular to each other. The roller itself will be non-metal, nylon 6/10 will be the material used.
However it remains to be seen if this design will be kept, as it will be revealed via simulation if the geometry and material choice can withstand the forces. If not by modifying the material or the geometry we can redesign it to suit the criteria.
