| 摘要 |
FIELD: drilling equipment. ^ SUBSTANCE: the invention relates to drilling equipment used to drill wells and holes with hydraulic defrostation of frozen rocks. The suggested bore bit comprises a hollow frame with an operating head reinforced with hard-alloy plates, a shank with connector and flushing ports in the operating head and in the shank. The suggested bore bit is peculiar because of a spring bushing installed within the frame, the bushing has radial bores and a guide assembly which ensures that the radial bores of the shank are adjusted with the bushing when the bore bit is switched to hydrodefrostation mode. Furthermore, the frame bore has a ledge, while the spring is installed between the frame ledge and the bottom of the bushing. The bore bit guide assembly is a spline joint of the bushing and the shank, or a rod on the bushing exterior, which is positioned in a slot inside the shank. The bore bit is also fitted with the stop limit for the spring bushing, which is a threaded bushing installed in the shank cavity with back threading, or is a rod connected with the frame shank. ^ EFFECT: expanded application field, increased effectiveness of the bore bit with hydrodefrostation, considerably facilitated bore bit switch from operating mode to hydrodefrostation mode. ^ 6 cl, 3 dwg |
