Abstract: The invention covers a mounting structure for heavy duty equipment, such as excavators and the like, to provide rotary and linear feeding thereof to the work. The device has a ground support plate, preferably circular, surrounded by a spaced annular base. The base supports a concentric circular main support carrying the equipment mounting platform and suspends a mechanism including the ground support plate and a secondary support body. The ground support plate can be raised, lowered and horizontally displaced with respect to the main support and the secondary body with the ground plate as well as the devices used for raising, lowering and displacement may be turned around a vertical axis which is concentric with the main support.