Patent GB-834879-A (GB)
Title: Improvements in collapsible pile cores
IPC: E02D7/30
Filed: 1958-11-11
Abstract: 834,879. Piles, removable driving cores. RAYMOND INTERNATIONAL Inc. Nov. 11, 1958 [March 20, 1958], No. 36245/58. Class 68(2) A tapered collapsible pile driving core comprises a core head 22, a plurality of leaves 23, 24 and 26 and a collapsing bar 27. Each leaf comprises a curved plate 24 (Fig. 9), two radial plates 29 and 31, a stiffening plate 32 and a top plate 33 (Fig. 3) welded together. The leaves 23 and 24 are attached to the core head 22 by long bolts 35 (Fig. 4) and the leaf 26 is attached by short bolts 40, the bolts pass through clearance holes in the end plates of the leaves. A wire lifting sling 44 (Fig. 2) passes through the core head. The leaves 23 and 24 hinge about a rod 83 (Figs. 9 and 3) and are held together by a wire 79 passing through upper lugs 81 on leaf 24 and lower lugs 82, on leaf 23, which have an enlarged opening for the wire. The leaves are separated by wedges 46, 47, 46a and 47a and the core is expanded to the position shown in Fig. 9 by upward movement of leaf 26. The leaves are retained by a loose wire bond 71. The core is collapsed by lifting the core head 22 when the short bolts 35 raise the leaf 26 before the remaining leaves; in order to provide additional force to produce relative movement of the leaves, means operated by the collapsing bar are provided. These means comprise a lever 49 (Fig. 4) supported by a bearing 58 mounted in the leaf 26. Projecting into a slot in the leaf 23 is an eccentric portion 61 which bears down on the bottom of the slot as the end of the lever is raised, until its movement is limited by a stop 68. A similar assembly operated by a lever 51 acts between leaves 26 and 24 As the core head is raised it lifts the collapsing bar 27 and rotates the levers 49 and 51 which forces the leaf 26 upwards relative to the leaves 23 and 24 and relieves the radial pressure on the core. Further movement of the head results in the leaf 26 being raised by the short bolts 40 so that the wedges 46, 47, 46a and 47a continue to slide over one another and the eccentric portions 61 and 62 run in the slots in the leaves 23 and 24, these leaves are ultimately lifted by the longer bolts 35. In order to hold the core in the expanded position while it is being placed in the pile shell a latch is provided which holds the leaf 23 against the core head 22, the leaf 23 holds up the leaf 24, since the lugs 82 are under the lugs 81 and the leaf 26 is held up by the levers 49 and 51. In a modification the core has four leaves, is parallel sided and has projections 233 (Fig. 20) which co-operate with corrugations 234 in the wall of the pile shell. To produce positive radially inward movement of the leaves as the core is collapsed, wire loops are provided, connected to pins near the outer edge of the leaves. As two of the leaves are raised the middle portion of the loop is lifted, pulling the ends and hence the leaves inwards. (Not shown-see Figs. 21 and 22). The resistance of the core to bending is increased by lugs 401 and 402 (Fig. 33a) on one leaf which cooperate with a lug 403 on a relatively non- moving leaf to resist the longitudinal movement which accompanies bending of the core. This construction is described with reference to the parallel sided fourleaved care. In a further modification (Fig. 23) the wedges 320, 321, 322 and 323 which expand the core are centrally situated. Further constructions employing centrally disposed wedges of modified shapes are illustrated in Figs. 24, 26, 27, 28 and 29 (not shown).