| 摘要 |
<p>947,835. Boring earth &c. H. B. WILLIAMS MANUFACTURING CO. June 19, 1962 [July 28, 1961], No. 23634/62. Heading E1F. In a drag bit having replaceable blades 19, each blade has a planar leading surface 36 with cutting fingers 38 and a projection 50 for deflecting cuttings upwardly and outwardly. Each projection engages a projection 52 on the rear surface of the preceding blade so that apertures 46, 48 for flushing fluid are formed. Specification 774,075 is referred to.</p> |
