发明授权
US06431295B1 Rock drill 有权
摇滚钻

Rock drill
摘要:
A drill including a stem (2) having at least two discharge grooves (3,4) for discharging drilling dust and helically circumscribing the stem (2), a drill head (5) provided at an of the stem (2) opposite the end provided with the shank and having a plurality of bits (7-9), which are formed of hard metal and project radially beyond the drill head (5), with the drill head having a plurality of drilling dust grooves (10-12) which separate the bits and number of which exceeds a number of the discharge grooves (3,4), with at least one pair of the drilling dust grooves (10,12) passing into a common discharge groove (4), and with the drill further having a helical groove section (13) forming a common transitional region between the at least one pair of the drilling dust grooves (10,12) and the common discharge groove and the passing cross-section of which is smaller than the passing cross-section of the common discharge groove.
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