Patent GB-225290-A (GB)
Title: Improvements in or relating to apparatus for forming concrete piles
IPC: E02D7/30
Filed: 1923-08-30
Abstract: 225,290. White, A. E., (Raymond Concrete Pile Co.). Aug. 30, 1923. Piles; piles, driving.-Apparatus for forming concrete piles in the ground comprises a circumferentially corrugated shell of comparatively thin sheet metal, and a correspondingly corrugated driving core composed of separable sections adapted to be joined end to end. The core may have radially movable corrugated parts to permit insertion into and removal from the shell, and the shell may be made in sections joined end to end. The core shown in Fig. 1 is designed for use when the shell has to be sunk in sections, as in underpinning work, and may be modified for use with a tapered shell. It consists of sections each divided lengthwise into two parts 83, 84. The core parts are inserted into the lowest shell section and expanded to receive a shoe 85 which is secured by a pin 86. An inner sleeve 87 is then inserted which is provided with longitudinal ribs engaging circumferential ribs 89 on the core parts and holding the latter in contact with the shell. To engage the next core section the parts of the latter are collapsed so that the flange 90 can pass below the flange 91 on the lower section. Pins 92 are then inserted and the shell section slipped over the core, after which the next sleeve section 87 is inserted, thereby expanding the core and bringing the flange 90 under the flange 91. The sleeves 87 are held together by binding rods screwed into ears thereon, so that to remove the hore, the sleeves 87 are raised and disconnected in succession, after which the core sections can be collapsed and successively removed. In the modification shown in Fig. 5, the core sections 95 are composed of separable parts with overlapping lugs 96, and are assembled by means of locking rods 98 passing through holes in the lugs and screwed together in sections. Fig. 9 shows another form of core and illustrates three stages in the sinking of a shell 102 oy means of a jeck 100 under a building &c. 99. In stage B one section has been sunk and the next is in position; in stage C two sections have been sunk, while in stage D the earth in the driving core has been removed by an air blast from a pipe 101. The core sections 103 are not corrugated, but are provided with slots to receive corrugated members 104 which are forced outwards by sleeves 105, both core sections and sleeve sections being connected together by screwing as the sinking proceeds. The shoe or point used with an open ended core may be in the form of a short tube 111, Figs. 5 and 9, of thin metal which will collapse when hard rock is encountered, preventing damage to the core and sealing the shell against ingress of water. Fig. 15 shows a non-collapsable corrugated core composed of sections 112 having spigot joints which may be of the tapered thread type, and is screwed into or out of the shell by a tool which engages internal lugs 114. In any of the forms described the upstanding corrugations of the core may be made narrower than the interior hollows of the shell, so that a slight clearance 115, Fig. 17, is left. The core can then be lifted slightly prior to unscrewing so as to facilitate this operation. The shell may be formed by bending a sheet of steel to cylindrical or conical form securing the ends together and then rolling in the corrugations on a mandrel. The edges may be joined by riveting or otherwise, or they may be left free in which case a joint as shown in Fig. 18 is preferably provided in which one edge of the shell 116 is formed with a socket 119 to receive the other edge. The shell is then easily fitted to the core and secured by wire tires. The corrugations may be of wave form, preferably about a quarter or five-sixteenths of an inch deep and from one inch to one inch and a quarter in pitch, and may be helical and of multiple thread type. The form shown in Fig. 23 in which the lower face 122 of the corrugations is .nearly horizontal may be used in some cases.