1. The brief introductions of 28 meters crawler rotary pile drilling rig with circular power rod With hydraulic crawler retractable chassis, self-lifting and falling foldable drill mast, Telescopic drill pipe, rotary pile drilling rig with circular power rod is a kind of construction machinery suitable for drilling in building foundation engineering. It is mainly suitable for the construction of sandy clay silty soil and other soil layers. It is widely used in the construction of cast-in-place piles continuous walls foundation reinforcement and so on. Compared with the ordinary rotary drilling rig, the rotary pile drilling rig with circular power rod has many objective advantages, such as drilling the concrete ground, the hard sand soil layer, the rock layer and so on. It is suitable for large engineering construction, high speed rail and railway construction. The machine works with fast speed, high efficiency, good drilling quality, oil saving and durable. 2.The features of28 meters crawler rotary pile drilling rig with circular power rod The folding mast structure is adopted. The structure is simple and exquisite, and its durability is good. The whole machine has good stability, cost saving and convenient maintenance. The upper guide structure ensures the perpendicularity of the drill pipe and the ground, so that the construction is more convenient, the construction efficiency is improved, and the safety is increased. The power head adopts the original patented structure, the design is more reasonable, the lubrication is reliable, the power is strong, the cost is economic, and it is not easy to damage, so it is easy to maintain. The main winch is equipped with imported hydraulic motor, which has a sensitive response and can be freely lowered when used. The lifting speed can reach up to 82m/min, which greatly improves the construction efficiency. The main winch is placed at the right front side of the operator, so that the operator can observe the working condition of the main winch at any time and avoid the phenomenon of disorder caused by other factors. The quality of the national inspection free raw materials and matching parts is more guaranteed. The double winching winch is selected with infinite rotation. The main winch is guaranteed to achieve the rated load. The winching speed of the single winch is 100m/s, which is increased by two times compared with that of the previous year. The hydraulic system exclusive of reasonable matching, the summer temperature is normal excluding radiator.