QTZ40 tower crane, as the latest model in domestic market at end of 20^th century, is a hydraulic auto-lift tower machine characteristic of upper-circumgyrating, horizontal arm and variable range with small cabin. The lifting moment is 400KN.m, the independent installation height is 29m, and with attachments the lifting height can reach 120m. The maximum load is 4t. There are two specifications of work range: 42m、 46.8m、 50m.

 With scientific design, beautiful appearance, the crane is superior in quality, reasonable in price, safe and reliable in operation, and easy to maintain and repair. It is an ideal construction machine for construction enterprises. The machine has four kinds of work structures: lifting, circumgyrating, variable ranges, and top lifting. The four structures can work in combination as well as independently so as to improve work efficiency. The top lifting structure is used to increase the height of the tower or lower the tower. The lifting structure makes use of tri-speed motor, with three kinds of speeds: quick, intermediate and slow positioning. For circumgyrating, wire winding motor speed-adjusting or double-speed motor speed-adjusting can be selected according to specific requirement so as to satisfy different demands. The lifting arm can rotate 540º to the left and right. The circumgyrating and range adjusting are agile and reliable, and the hoisting positioning is accurate. Thus the crane can satisfy the need for vertical and horizontal transportation in construction operation.