1848.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



311 



ATMOSPHERIC PILE-DRIVING MACHINE. 

 Patented by Clarke and Varley. 



STide Elevation of a Single Machine. 



This apparatus has been lately used for driving the piles of the 

 coflFerdam for Irongate, St. Katherine's Docks. The inventors 

 state that by this machine, piles may be driven at half the expense 

 of driving tJiem by the ordinary machine worked by hand, and in 

 about one-sixth of the time. Mr. Crate, the clerk of the works 

 at the above docks, states that he drove forty-two piles, 18 feet 

 deep, into a bed of very hard compact gravel, at the rate of three 

 piles each tide of about 3k hours ; and to drive one pile only, by 

 the ordinary hand-engine, occupied five tides before it could be 

 finished, and even then was left 2 feet above the height required 

 to be driven. Mr. Harrison, the engineer, also certifies that the 

 Atmospheric Pile-Driver gave him entire satisfaction. 



This machine consists of a vacuum cylinder of wrought-iron 

 (A), closed at the bottom and open at the top, having an air-tight 

 piston, and self-acting slide-gear, fixed to any convenient part of 

 the frame of a common pile-engine. The piston-rod is connected 

 to a chain which passes over a fixed pulley (B) on the top of the 

 engine ; to the end of this chain is suspended a pulley (C) ; over 

 this passes a second chain, one end of which is attached to the 

 ram, and the other, passing down under the bottom of the frame, 

 is brought up and affixed to the head of the pile. The power is 

 derived from a small steam-engine, fixed at any convenient spot, 

 which works an air-pump for producing the exhaustion. Com- 

 munication is made between the air-pump and the Pile-driving 

 Machine by small wrought-iron tubes, connected together by flexi- 

 ble joints of vulcanised india-rubbw. Thus the machine possesses 



Front Elevation of a Double Machine. 



the inciilculable advantage of being worhed at any required distance 

 from the steam-engine, and moved about with as much facility as a 

 common crab-engine. The mode of action is as follows : the ram 

 being supposed down on the pile-head, and the piston consequently 

 at the top of the vacuum cylinder, communication is opened by 

 the valve gear with the air-pump, exhaustion then takes place in 

 the cylinder, the piston descends by the external pressure of the 

 atmosphere, and raises the ram ; when the piston arrives at the 

 bottom of the cylinder, the valves reverse themselves, communica- 

 tion with the air-pump is then shut off, and the external air ad- 

 mitted under the piston ; equilibrium being now restored, the ram 

 falls with the full effect of gravity on the pile ; the valves are 

 again reversed, and the same operation is repeated. Thus a suc- 

 cession of short heavy blows is given, rapid of^ course in proportion 

 to the power of the steam-engine ; and, as by the arrangement of 

 the puHeys, the distance between the pile-head and the face of the 

 ram is always the same, a regularity of action is obtained, quite 

 unknown to the old pile-driver, the injurious effect on the head of 

 the pile, and rebound of the ram, consequent upon great height of 

 fall, avoided ; and the ram being permanently fastened to the 

 chain, the whole time lost by the re-attachment after every blow is 

 saved. The machine is so constructed, that it may be fixed in a few 

 hours to the frame of a common pile-engine. \ . 



Fig. 2 shows an arrangement by which one vacuum cylinder can 

 be made to work two rams, and, consequently, drive two piles at the 

 same time. A pulley (A>) is attached to the piston-rod of the 



