| 摘要 |
FIELD: drilling equipment, particularly devices adapted to drill blast holes in pits. ^ SUBSTANCE: device comprises frame, mast, rotary-feeding system, upper and lower tongs and drill string including drilling rods. Each drilling rod has tapered threads and cuts for upper and lower tongs receiving. Length of cut for lower tong receiving is formed in accordance with the following correlation: L>=d+a/sin(b), where d is tong mouth thickness, a is thread depth, sin(b) is sinus of thread taper angle. Method involves lowering upper rod downwards up to rod touching with lower rod thread; rotating upper rod without rod displacement, which results in lifting of low rod suspended to lower tong without lower rod rotation, wherein lower rod is moved along rod cuts to height spaced h distance from pipe connection and located under lower tong. ^ EFFECT: provision of safe rod threads connection, prevention of rod thread damage and increased durability of drilling string threads. ^ 4 cl, 7 dwg |
