GB1472493A - Sampling drill - Google Patents

Abstract

1472493 Boring earth &c WALLIS GEOCHEMICAL DRILLING CO PTY Ltd 20 May 1975 [28 May 1974] 21489/75 Heading E1F A sampling drill suitable for use in sand and similarly soft material comprises several drill rods coupled together to form a drill stem suspended from a drill head, each drill rod comprising a pair of concentric tubes defining a central passage and an annular passage. As shown, the lower end of the drill stem is fitted with a drill bit 14 having an inner chamber 17 connected through member 11 to the central passage of the drill stem, and having one or more passages 23 connected at one end through an annular space A to the annular passage in the drill stem and at the other end to discharge into the chamber 17 through a central boss 18. The inner chamber is provided with openings located adjacent the cutting edges 15, 16 of the drill bit so that cut material can enter the inner chamber. The member 11 is slidably mounted in the drill bit 14, its position being controlled by a device fitted at the upper end of the inner portion of the drill stem. When the member 11 is partly raised as in Fig. 1, air passed down the annular passage in the drill stem is discharged through passages 23 into the chamber 17, cut material entering the chamber being carried upwardly through member 11 into the central passage of the drill stem. When the member 11 is lowered, it seats in a recess 19 on the boss 18 to prevent cut material from entering the central passage. The member 11 is sealed in the neck of the drill bit by sealing members fitted into recesses 21, 22.