GB215051A - Improved operative tool for well-boring - Google Patents

Abstract

215,051. Jenkins, R. F., and Price, D. W. Jan. 8, 1923. Bore-hole apparatus.-In a well boring tool wherein advance cutters bore a hole and are followed by expanding reaming cutters which enlarge the hole, the advance bit comprises a body carrying an axial drill and one or more cutters cutting concentric annuli around the hole formed by the axial drill. The boring rods 26 are slidably and non-rotatably connected to an underreamer body 16 by a plunger 24 of square cross-section, the sliding motion being limited by pins 28 ; when in its lowest position, the plunger acts through lower bevelled surfaces and wedges 22 to hold in expanded position arms 18 pivoted at 19 in recesses in the bodv 16. The enlarged lower ends of the arms 18 have radial dovetail slots receiving tools 21 which are locked by dovetailed plates 21'; projections 18<1> on the enlarged lower ends engage recesses 18<2> in the body 16 to limit the movement of the arms 18. Below the body 16 is a bodv 1 with a central drill 2 held in a dovetail groove ; the body 1 is of substantially diamond shape in cross-section and at the end of each diameter is a cutter 7 adjustably held in grooves by a screw and slot connection. The bodies 1, 16 may be integral or separable, and in the latter case the body 1 may be capable of attachment to the boring rods 26. A central water passage communicates with four divergent holes 31 in the body 1.