| 摘要 |
The invention relates to drill instruments of percussion effect, in particular to drill perforator crowns, drill bits, that are used at extraction of solid minerals and at construction of underground mine workings. Drill instrument with impact effect for especially hard rocks has body that consists of tail element and head with fixed at its end prominent with respect to it main hard-alloy inserts working part of which has curvilinear surface. Hard alloy inserts placed at periphery of head with inclination and inserts on smaller in diameter neighboring circle are placed one with respect to another in height and in radial direction in such way that at bringing into coincidence radial planes of those going through axes of those inserts the working profiles of those intersect. According to the invention head of the body along periphery is equipped with additional inserts cutting edges of which and peripheral points on inclined inserts at bringing to coincidence radial places of those coincide, at that front working surface of additional inserts of head of the body is formed by end of cylindrical insert or its side surface, those are placed at negative angle. The invention promotes formation of more smooth re-distribution of loads on those inserts, due to that area of wear and breakage of those is decreased, especially at drilling very hard rocks, and as result stability of instrument is provided.
|
