GB1321995A - Hydraulically-operated driving mechanisms for underwater use - Google Patents

Abstract

1321995 Underwater pile driving mechanisms; boring earth &c INTERNATIONAL RESEARCH & DEVELOPMENT CO Ltd 27 May 1971 [29 May 1970] 26017/70 Headings E1F and E1H An anchoring spike 10 is driven into the sea bed by a driving mechanism comprising a heavy base member 13 having co-axial conical passages 11, 12 through which the spike 10 is guided by a rotatable ball member 14 and an upper member 17 which carries a variable frequency vibrator unit 16 that holds the spike 10. Hydraulic jacks 19 having ball joints (not shown) at their ends interconnect the upper and base members 17, 13 respectively and power sources 18, 20 for the vibrator unit 16 and the jacks 19 are provided. These power sources and various flow control valves (not shown) may be controlled from a surface vessel. In use the mechanism and the spike 10 are lowered to the seabed, whereupon the buoyancy of hollow upper member 17 pulls the spike 10 to a vertical position whatever the seabed inclination, the rotatable ball member 14 in base member 13 allowing this. The ball member 14 is then locked in position by hydraulic ram 15, the upper member 17 flooded and the spike 10 driven in by the combined action of vibrator unit 16 and the compression of hydraulic jacks 19. Ram 15 is then released whilst jacks 19 apply a predetermined reverse pressure to test the anchoring of spike 10 before the vibrator unit 16 is decoupled from it and the driving mechanism brought to the surface. In a modification (Fig. 2 not shown) a non-buoyant upper member is used, any sea-bed unevenness being overcome by the driving mechanism resting on hydraulically adjustable feet secured to the base member or the upper member. A subsea cover may also be driven in using the mechanism.