Tubular Base Arm Reinforcement for Deep Foundation Excavators

The patent applies local quality by positioning the sheave shaft between the upper guide arm connecting pin and lower guide arm connecting pin, creating a localized stress distribution zone. This specific positioning arrangement concentrates the structural reinforcement where needed most, allowing the arm to maintain overall strength while accommodating the bucket lifting device on the rear side.

The patent resolves the contradiction by introducing a vertical dimension consideration - placing the sheave shaft between the upper and lower guide arm connecting pins in the vertical direction. This spatial arrangement distributes stress across multiple dimensions rather than concentrating it in a single plane, thereby maintaining both rope winding stability and arm strength.

The patent segments the arm structure into distinct functional zones: the base arm with side plates, the guide arms (upper and lower), and the sheave shaft assembly. By dividing the structure into these separable components with defined connection points, the design achieves enhanced strength through proper stress distribution while maintaining manufacturing and assembly feasibility.

The sheave shaft acts as an intermediary element positioned between the upper and lower guide arm connecting pins. This intermediate component facilitates the transmission of forces while protecting the side plates from direct stress concentration, thereby enhancing side plate strength without requiring complex reinforcement structures.