GB331945A - Improvements connected with the production of foundations for poles and the like - Google Patents

Abstract

331,945. Callender's Cable & Construction Co., Ltd., and Bennett, P. M. April 19, 1929. Borehole apparatus.-A tool for enlarging boreholes in the ground comprises a tube and an inner rod positively controlling a linkage associated with cutters, the linkage comprising members pivoted together and to upper and lower heads, and the rod causing relative movement between the heads to force the cutters outwardly into operative position. In Fig. 1, a tube 1 is supported by a member 16 with rollers 17 and carries pivoted cutters 8 which have a pin and slot connection 10 to the connected ends of pairs of links 11; the opposite ends of the links are connected to upper and lower nuts 6 on oppositely threaded parts of a rod 2 whereby, on rotation of the rod, the cutters are expanded or retracted. The whole device is rotated by power or by handles 15. The cutters may be formed of T or L shape. In Figs. 3 and 4, an outer tube 33 has threaded openings 35 for adjustably securing it to the member 16, and contains an inner tube 27 and rod 26 to which are connected the upper and lower ends respectively of connected pairs of cutters 22; the tube 27 has keys 36 engaging ways 39 in the tube 33. A nut 29 engages a threaded part of the rod 26 and may be secured to the tube 27 by pivoted bolts 31. Further, collars 40, 44 may be connected to the tube 33 and rod 26 and connected by rods 42 to prevent relative longitudinal movement of these parts. In use, with the nut 29 free as shown in Fig. 3, the nut may be moved downwardly to move the tube 27 and thereby expand the cutters whereby, on rotating the device, as by means of a tommvbar engaging slots 47 in the upper end of the tube 33, a conoidal enlargement is produced with the wide part at the bottom: the nut may then be fixed and the cutters collapsed by rotating the rod 26. Alternatively, the collars 40, 44 and rods 42 may be removed and the tubes 27, 33 locked by pins inserted into registering apertures 48, 49, the cutters then being expanded or collapsed by rotating either the nut 29 or the rod 26: a conoidal enlargement with the upper part wide is thus produced. The operations may be combined. Means may be provided to indicate the amount of expansion of the cutters.