Base-free central lifting structure

The utility model discloses a base-free central lifting structure. Comprising a large disc, a lower horse seat arranged on the large disc, and a positioning device which is arranged between the large disc and the lower horse seat and is used for positioning the lower horse seat when the lower horse seat is placed on the large disc, the lifting device is arranged between the large disc and the lower horse seat and is used for driving the lower horse seat to lift to a preset height after the lower horse seat is placed on the large disc and is positioned by the positioning device; the lower end of the driving adjusting rod is in threaded connection with the large disc, and the upper end of the driving adjusting rod penetrates through the lower horse seat; the lifting adjusting gear is arranged at the middle end of the driving adjusting rod; the annular lifting gear is rotatably arranged at the lower end of the lower horse seat and is meshed with the lifting adjusting gear; the driven lifting assemblies are arran