Electric single-beam crane for annular track

The electric single-beam crane comprises an annular guide rail set and a circulating displacement assembly, a top fixing piece is fixedly installed on the inner side of the annular guide rail set, and the top of the circulating displacement assembly is fixedly installed on the inner side of the annular guide rail set through the top fixing piece; a plurality of transfer lifting appliances are slidably mounted on the outer side of the annular guide rail group, and an electric hoist is fixedly mounted at the bottom of each transfer lifting appliance through a bolt. The first clamping plate and the second clamping plate which are located on the two sides correspondingly and the servo electric cylinder on the top form a pincerlike structure with a downward opening to be clamped to the outer side of the top of the steel frame, and the situation that the transfer lifting appliance topples over when moving on the annular guide rail set is avoided; the limiting bolts I and the limiting bolts II inserted into the limi