Patent GB-779607-A (GB)
Title: A gripping or jacking device for objects such as caissons or pilings and the like
IPC: E02B17/08
Filed: 1954-09-21
Abstract: 779,607. Piles &c. driving. LUCAS, J. E. Sept. 21, 1954 [July 19, 1954], No. 27257/54. Class 68 (2). Caissons and piles are gripped for forcing into the sea bed, or for withdrawing therefrom, particularly for raising a barge from the water to serve as a well-drilling platform, by a mesh arrangement of cables which tightens upon the caisson when the mesh is extended axially. The deck 10 of the barge has a number of wells 12 in which the caissons 14, generally of circular section, are accommodated, being held temporarily in position by a clamping ring 16. When the barge has been correctly positioned, the caisson is lowered through the well and eventually forced to a position of stability into the sea bed, by the alternating movement of two gripping devices 18, 20, which climb up the caisson so that the whole weight of the barge forces it into the sea bed. The gripping devices are substantially identical, and, as regards the upper device 18, consists of cables 58U each forming because of its oblique disposition on the caisson, an elliptical loop, the loops being attached at the ends of the major axes of the ellipses to rings 40U, 42U which are carried respectively on the piston rods 54U of peripherably spaced jacks 50U and on the piston rods 52U of similarly spaced jacks 48U. The jacks are secured to radial plates 32U having steps 36U, 38U which determine the end positions of the rings 40U, 42U, the plates 32U being secured to rings 28U, 30U, the latter being slidable on vertical rods 26 secured at 24 to the deck 10. The jacks 48U, 50U are thus each capable of extending the cable mesh axially producing a radial contractor thereof to grip the caisson. The cables 58U are attached to the rings 40U, 42U by links 64, 68a and brackets 66, 68, the lower ends of the upper links 64 being pivoted to plates 60 to which the cable ends are pinned. The cables run through channels in plates 62 carried by the lower links 68. The inner faces of the plates 60, 62 are serrated to bite into the caisson surface, or are rubber lined to increase the grip. The cables are prevented from chafing against one another at the crossing points by members 70 having separated guide channels for the cables. The members 70 also, have serrated or rubber inner faces, and are supported from the ring 40U to maintain the form of the mesh by chains 78. The lower gripping device 20 also is slidable on the guides 26, and the operative connection between the devices 18, 20 is provided by jacks 82 secured to the lower ring 30L of the device 20 and having piston rods 84 which extend through the ring 28L and are connected to extensions 86 of the plates 32U. The jacks 82 are double acting, the pipes C feeding one end of the cylinder and the pipes A, B, the other end. By selective operation of the jacks 82, and the jacks 48U, 50U, 48L, 50L, the devices 18, 20 can be raised or lowered alternately, the stationary device 18 or 20 being locked on the caisson whilst the other device is re-positioned on the caisson, and the climbing up or down action of the two devices produces a driving home or a withdrawal of the caisson. The pipe B of each jack 82 may be closed when the pipe A is vented, so as to produce a trap 114 at the end of the cylinder bore, into which a reduced end of the piston slides. This limits the extent to which the device 20 can approach the deck 10. In a modification, the cables are arranged as right and left handed helices, anchored to the top and bottom rings and protected from chafing at the crossing points.