Define the Problem
The new cast joint must have the same strength and movement characteristics as the old joint and must maintain the same length dimensions as the old joint. It must be easily weldable and the assembly must be feasible using Pierce Pacific's current methods. At a minimum it must maintain the same overall cost and weight. Working drawings of the joint must be included with the joint design.
It should be faster to assemble, incorporate continuous welds, and contain weld preps in the casting. It should self index for assembly and should have a built in pin keeper.
Brainstorming produced a number of useful ideas. The casting will be welded to the body of the main boom, and the horizontal and vertical welds were offset from each other to increase the weld's fatigue life. By offsetting the stress concentration due to the welds, crack propagation becomes more difficult. Weld backing plates and a single pin keeper were designed into the casting to reduce assembly time. Utilizing flanges on the outer edges of the casting minimized the weight while retaining the load carrying ability.