GB1521627A - Ground vibrator - Google Patents

Abstract

1521627 Stabilizing soil VAN KOOTEN BV 6 July 1976 [7 July 1975] 28037/76 Heading E1F [Also in Division F2] A ground vibrator for densifying soil or loosening piles comprises a vibrator housing 21, unbalancing means 14 accommodated in the housing 21 and a motor 64 for driving the unbalancing means 14, the motor 64 being accommodated in a motor housing 10 elastically connected at 35 to the housing 21 and being coupled through a flexible coupling 12 to the unbalancing means 14. The housings 21, 10 are driven into the ground by means of a tubular rod (7) (Figs. 1, 2, not shown). As shown, the flexible coupling 12 comprises an elastic ring 61 which is torsion-resistant but accommodates relative tilting or offsetting of the axes of the shafts 11, 13 of the motor 64 and unbalancing means 14. Alternatively (Fig. 8, not shown) the flexible coupling may comprise a universal shaft connected to the shafts 11, 13 through elastic couplings. The elastic connection between the housings 10, 21 comprises a cylindrical tie member 35 of elastic material. The unbalancing means 14 includes a cylinder 17 to which is fixed an unbalancing weight 45. Two further unbalancing weights 46, each of a mass of half that of weight 45, are journalled for rotation in the cylinder 17 but the rotation is limited by stops 54, 55 so that when the cylinder 17 is rotating, the weights 46 are held in either the position of Fig. 6 or that of Fig. 7. The motor 64 is of a pole-changing kind having a speed ratio of 2:1 such that the unbalancing means are in the smaller unbalancing position (Fig. 7) when driven in one direction with the higher speed, but are in the larger unbalancing position (Fig. 6) when driven in the other direction with the lower speed. The parameters are preferably chosen such that the radial force exerted by the vibrator is the same in these two modes. The modes of Fig. 7 and Fig. 6 may be utilised when the vibrator is passed through clay and sand layers respectively, and for loosening the ground water may be pumped through nozzles 30.