| 摘要 |
1,084,269. Drills. SANDVIKENS JERNVERKS A.B. Dec. 11, 1964 [Dec. 14, 1963], No. 50520/64. Heading B3C. A drill comprises a sleeve 10, Fig. 1, a sleeve 11, which carries a drill bit 12 having cutting inserts 13, and an inner tube 14. The end of tube 14 is castellated to provide openings 23, and abut a ring 22. Bores 26 are provided in drill bit 12 and are surrounded by an extension 27 of tube 11. A gas or liquid flushing medium is supplied to annular space 15 through openings 17. It is divided into two streams 29a, 29b, the former passing through openings 23, and being deflected rearwardly by ring 22, whilst the stream 29b passes to the cutting inserts, and thence through ring 22, to join up with stream 29a. In a modification, a flange 31 is integral with the drill bit, Fig. 2. In a further modification, the rearward flow is obtained by aid of one or more rearwardly inclined holes 32, Fig. 3. In a still further modification, internal tube 141, Fig. 8, has a brazed on portion 142, thus forming an annular slit 145. In another modification. portions (147), (148), Fig. 9 (not shown), are held apart to form slit (149) by asleeve (150) having holes (153) for the passage of the flushing medium. In yet another modification, tube 11 is thinner than tube 15. The drill or the work may rotate. |
