Motorized 180° Rotation Fixture, Raghav Singh

A 40 kg hydraulic turning joint was being rotated by hand during assembly. I designed a fixture that removes the manual handling and holds the part at any orientation through the build sequence, sizing it from the worst-case torque rather than the balanced condition.

Fixture assembly in Fusion 360 — FIG 1 · Fixture assembly, Fusion 360. Motor and worm gearbox at left, driven shaft through two plummer-block bearings, part mounted on the central tabletop plates.

Fixture next to a standing operator for scale — FIG 2 · Working height and reach checked against a standing operator.

Design data
Part	40 kg hydraulic turning joint
Requirement	141 N·m at rotation axis
Delivered	184 N·m, a 1.30× margin
Drive	Worm gearbox + electric motor, jaw coupling; self-locking under load
Supports	Spherical roller bearings in split plummer-block housings, ×2
Indexing	Spring index plungers, ×4
Base	Welded steel stand, 4 legs, cross-braced, floor-anchored
Software	Fusion 360

Engineering decisions

Torque sized from the worst case. The 141 N·m requirement comes from the joint at maximum offset from the rotation axis, not the balanced position, since that offset is the condition the operator actually has to overcome.
Worm drive chosen for back-drive resistance. The joint holds position with no brake and no power applied. I picked the gear type for that safety property, not only for the reduction ratio.
1.30× margin, stated as such. Enough for the duty cycle and start-up inertia without oversizing the motor, shaft, bearings, and frame downstream.
Specified to purchasable parts. Gearbox, motor, bearings, housings, plungers, and anchors all selected from supplier catalogs so the design could be quoted and released to build.