Seismic Table

Large lifting and rotating table. 

Client builds server cabinets and racks. For Seismic Use Group III certification of these products, the racks have to be subjected to testing. The tests include being properly mounted and held at angle up to 60 degrees both forward and side facing. Client wanted a 10 ft by 10 ft tilting and rotating table capable of lifting 8,000 lb.

The 8,000 lbs requirement set the scope for the project: Lift two SUVs. The table was broken into three large weldments. A finite element analysis (FEA) was performed on the structure. The rotating frame, or table top, FEA had 4 server racks fully loaded located at a corner. This scenario is the worst loading condition and most unlikely usage case but possible so that dictates the design. The bearing design lead to selecting a slew ring gear and increasing the rotation from 90 degrees to infinite. Again the 8,000 lb load at 7 ft from center, with a factor of safety, selected a hefty gear.  Some redesign was done taking into account weld angles, torch access, and construction. The table surface was three pieces of steel plate with threaded holes on a 12" by 12" matrix allow for standard fixturing.