GB487057A - Improvements in ramming devices and methods of use in constructing concrete piles and the like - Google Patents

Abstract

487,057. Concrete piles. BRITISH STEEL PILING CO., Ltd., and HILEY, A. Dec. 14, 1936, No. 34315. [Class 68 (ii)] A ramming device adapted to be inserted into a preparatory tube in the construction of concrete piles, comprises a wedge-like gripping member 4, Fig. 1, adapted to engage the inner wall of the tube 5, and one or more auxiliary wedges 3 disposed between the member 4 and the body 1 of the ram, so arranged that when engaging, relative movement takes place principally between the member 4 and the wedge 3, and when releasing, the initial relative movement takes place between the body of the ram and the wedge 3. The ram is provided with a reaction member consisting of a toggle 6 pivoted on a loose pin 8 and having teeth 9 to engage the tube 5. The toggle 6 is pivoted to a link 11 having at its upper end shoulders 12 and 13. The suspending ropes 15 are connected to the link 11 and to the wedge 3. Upward movement of the link 11 is limited by contact of a distance piece 16 on the shoulder 13 with the head of the body 1, and upward movement of the wedge 3 is limited by resilient packing 21 making contact with a pin 18 in the body 1, while downward movement is limited by a shoulder 19. The base of the ram is formed with a threaded hole for a plug 25 which may be replaced with a cutter for taking samples of ground. A modified form of ram is shown in Fig. 6. In this form, the reaction member 9 is retained and guided by pins 8 and 32, and its downward movement is limited by the buffer 23 which bears on resilient washers 37. In operation, the ram is lowered by the rope 15, the wedge 4 being retracted, and, in the form shown in Fig. 1, the toggle 6 raised. When the ram comes into contact with the concrete in the tube 5, the member 4 slides down and makes contact with the tube. If the tube is now driven downwards, an upward pressure is exerted on the base of the ram, and the wedge 3, carried upwards by contact of the shoulder 20 with the shoulder 19, presses the wedge 4 against the tube and exerts a corresponding pressure on the toggle 6 or the reaction member 9, the buffer stop 23 yielding slightly. When the upward pressure on the plug 25 is removed, e.g. by giving an upward blow to the tube 5, the ram is released, initial movement starting between the body and the wedge 3, and moves downwardly till it again rests on the concrete. By a reciprocating movement of the tube 5, the ram may thus be caused to move down the tube and force the concrete downwardly. In making a concrete pile, the tube 5, Fig. 9, is driven with the ram 1 wedged in the lower end thereof. The ram is then lifted by the rope 15, and a charge of wet concrete poured into the tube. The ram is then lowered to rest on the concrete. The tube is then raised by upward blows of the hammer 40 till the ram, which remains stationary, is at the end of the tube ; the tube is then driven down, carrying the ram with it and forcing the concrete to spread to form an enlarged footing, Fig. 12. In softer strata, the same effect may be obtained by reciprocating the tube when the ram is resting on the concrete charge, causing the ram to travel downwardly and force the concrete out of the tube. A pilot pile may be driven through the mass of concrete by means of the ram.