WELL-WIDENING DEVICE Russian patent published in 2004 - IPC

FIELD: mining industry. SUBSTANCE: Device has body with central axial passage, external ring-shaped projection and axial grooves. Tools in shape of hydrodynamic blades with positive attack angle in direction of rotation are hanged from joints inside axial grooves. Inside the central axial passage hollow shaft is placed and connected to the body with its upper end. Outside the shaft in top-down direction thrust bushing, spring and bush sleeve are located consecutively, capable of interaction and progressive or reciprocal movement. Around the hollow shaft traction bars are located, each of them at one end connected to corresponding tool by means of joint, while other ends are connected to the bush sleeve. Supporting member with axial passage and radial ports is fixed to the lower end of the hollow shaft. EFFECT: increased durability and effectiveness of device. 1 cl, 3 dwg