GB1359030A - Method and apparatus for driving or extracting piles - Google Patents

Abstract

1359030 Pile drivers BOLT ASSOCIATES Inc 21 Dec 1971 [29 Dec 1970] 59480/71 Heading B3H [Also in Division F2] A pile driver or extractor has a reciprocable piston 24 in a cylinder 22 which is closed at its lower end by a piston 60, Fig. 3, or a fixed closure plug 60A, Fig. 21, to define a bounce chamber 34, Fig. 3, in which air or steam is compressed during the downstroke of the piston 24 to cause upward recoil of the piston. The piston 24 preferably does not impact against the piston 60 or plug 60A. The air or steam is supplied to the bounce chamber 34 from a compression chamber 38 via a valve 76 which is opened by the piston 24 as it descends. The valve 76 may have plugging part 93 so that during further descent of the piston 24 the bounce chamber and compression chamber are isolated. The air or steam are supplied by a line 94 to a central chamber 72 connected to the compression chamber 38 by a wide port 102 which is closed by the valve stem 74 as the valve opens and by a continuously open restricted port 100. The air or steam from the bounce chamber 34 is exhausted through ports 106 which are uncovered by the rising piston 24. A muffler assembly 109 surrounds the ports 106 and comprises concentric annular chambers 102, 123 with a steel wool filter 122, Fig. 6. Any oil in the air or steam mixture is trapped in the filter 122 and drips into a reservoir 134 in the annular chamber 123, to provide a supply for a lubricating system (see Division F2). The chamber 23 above the piston 24 has exhaust ports 216, Fig. 1, which may be permanently closed by an elongated plug 230A to provide a double-action stroke for the piston, Fig. 14 (not shown), or the chamber 23 may be closed by a head or head plug 230, Fig. 15, to leave the ports 216 open for a single action stroke. If the piston is raised above its normal upper limit the trapped air between it and the head plug 230 also provides double-action, Fig. 16 (not shown). The lower end of the pile driver or extractor has a detachable coupling 30, Fig. 3, connected to an adapter 32 which fits the pile 28 which may be a pipe pile, H-beam pile or a timber pile. The pile driver or extractor is guided on greased bars 200, Fig. 1, engaged with projections 204, 206. For extracting piles the pile driver assembly is suspended from a cable (236), Figs. 17 and 18 (not shown), of a crane via a fluid pistoncylinder coupling (240). The coupling (240) acts as a shock absorber or an overload protection device. The piston is accelerated upwards as above and the upper closure of the cylinder 22 is arranged to provide for double-action, Fig. 16 (not shown), or even impact. The pile driver assembly is attached to the pile (28), by a loose coupling (250) and the pile is raised by a steady pull on the cable (236) by the crane, and by pressurization of the chamber (244).