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THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[Jan. 



per square inch, and about 100 strokes per minute. Under the boiler 

 is placed the supply cistern. In the centre of the framing, and on each 

 side of the boiler is a pair of inclined cylinders 5i inch bore, with 

 solid pistons working well without packing, and 14 inch stroke, which 

 act on right angled cranks; and the gearing, drums, Sec, described in 

 the motions of the machine ; the shaft centres are 1' 3" apart, the 

 spur wheel has 5(3, and pinion 19 teeth; bevels 101 and 40 teeth; 

 saw pulleys 1' 9" and lOA inches diameter. The ram is generally raised 

 from 4 to 5 times a minute, the steam being at 80 lb. per square inch. 



For river work the machine is made much more compact, the appa- 

 ratus is placed on each side and over the boiler, so that the stage is 

 little more than half the length of the machine shown in the engraving, 

 and it is also sometimes made with an apparatus for driving one pile 

 only, consequently requiring smaller power. 



In the drawing, fig. 1 is a side elevation of the machine ; fig. 2, ele- 

 vation in front of leaders, showing saw, &c. ; fig. 3, a section taken 

 in front of gearing, &c. ; fi^. 4, a plan of gearing end ;with leaders 

 and ladders removed, and showing saw in plan, similar letters refer to 

 similar parts in each figure. 



Taking iip ihe pile. — The ram A being secured by placing the stop 

 B under it, by means of the small ropes attached to the latter, and 

 passing over the small pulleys C C, to within 3 feet of the stage. The 

 dogs D are made fast to the pile (fig. 3,) the rope attached to which 

 passes upwards througli the small guide pulleys, and over the outer 

 pulley E, passes downwards and is coiled round the pulley F, fixed on 

 the shaft G, which being made to revolve, raises the pile to its place 

 between the leaders, and is then secured by the loose stay H, and the 

 iron work H' placed round it for guiding it perpendicularly. 



Driving the pile. — The stop B being withdrawn from under the ram 

 A, the ram is raised by a rope, which being secured to a staple on the 

 top journal passes down under the pulley I, then upwards over the 

 pulley K, and again downwards to the drum L, upon which the rope 

 is coiled, the drum is placed on the shaft G, which is made td revolve 

 oy the spur wheel N, working in the pinion O, on the lower shaft P, 

 ■which shaft revolves by the action of two cranks Q (Figs. 1 and 3,) 

 placed on each end of the shaft P, the cranks are set at right angles 

 to each other, and are worked by the connecting rods R, attached to 

 the piston rods, which are furnished with slide parallels as shown in 

 fig. 1. The slide valves of the piston are worked by the eccentric V, 

 on the end of the shaft P. Steam is supplied to the cylinder by the 

 pipe S, from the boiler T; the boiler is supplied with water from the 

 cistern M, (fig. 1) by the pump W, which is worked by the eccentric 

 rod X, fixed on the spur nave at Y, or by the handle at Z ; the supply 

 of steam is regulated by the handle (a) acting on a valve in the steam 

 pipe (S). The drum L consists of a fixed and a loose cylinder, the 

 latter revolving by the friction of the former (fixed), and is brought 

 into or out of contact by the hand lever (Y) figs. 1 and 4, which has 

 a fulcrum attached to the standard. 



The follower/' is furnished with a pair of tongs or clippers, which 

 takes hold of a staple fixed in the ram, and carries it to the top of the 

 frame; then when the top of the tongs is pressed closer together, by 

 coming between the contracted checks e' e', the lower part opens and 

 allows the ram to fall. 



For working the apparatus the engine-tender stands at the valve S, 

 and a man at the lever j/ of each machine. For raising the ram the 

 man turns on the steam at the valve S, which sets in motion the appa- 

 ratus of each machine, and coils the rope round the drums, at the same 

 time raises the ram, as soon as the latter reaches the top of the leaders, 

 the ram is detached and descends, at the same moment the engine- 

 tender turns off the steam, and the men at the levers y throw the drum 

 out of gear, which allows the clippers and chain to descend again and 

 lay hold of the ram ; when the drum is again thrown into gear, the 

 steam turned on and the ram again raised, and so the operation is con- 

 tinued until the pila is driven. 



Draming a pile. — Chain tackle is secured to the pile and passed over 

 the top pulley to the drum L, and is then drawn by applying the power 

 to turn the drum of the apparatus. 



The Saw Apparatus consists of a circular saw b, 4 feet diameter, 



having teeth set 3 inches apart, secured to the end of a beam c, which 

 beam works on the upright shaft d for a centre, and slides laterally on 

 on the iron arc e ; when used the saw is adjusted to the proper height 

 by the screws/, and a bar having a hook in one end and fitting into a 

 staple in the beam's end, is used to press the saw against the work, 

 the bevel pinion g being raised into gear by the foot lever /i, (fig. 4), 

 motion is given to the pulley i and ;, and band k, which W9rk the 

 saw b. The operation of sawing off the end of a pile takes less than 

 a minute. 



Progressing motion. — The hook I being fastened to a driven pile, 

 and the rope passed over the pulley m attached to the side of the 

 frame to the pulley F, round which it is coiled twice, and the end held 

 by a man — motion being now given to the drum, the machine pro- 

 gresses — this motion is shown by the dotted rope fig. 1, it should be 

 stated that the frame is intended to be supported upon six railway 

 wheels, which run on a temporary rail laid on the top of the piles as 

 they are driven. There is another mode of progressing, but which is 

 not found to answer so well, viz. by means of two sledge beams faced 

 with iron and attached to the under framing, these are placed six feet 

 apart from centre to centre, and pass under the whole length of the 

 machine, and slide on small iron wheels fixed to standards, which are 

 placed loose on the piles. 



The plumb-bob I suspended to a line regulates the pile being 

 driven perpendicularly, and Y is a lever attached to a friction band 

 break passing over the end of the drum, which is only used occa- 

 sionally. 



It is remarkable that writers on mechanics have not been able to 

 agree on the precise manner in which the force of the blow given by 

 the ram of a pile engine should be estimated, and the question appears 

 to have been greatly confused by confounding it with the effect pro- 

 duced in sinking the pile. Now it is one thing to estimate the force 

 of a blow, which is simply to determine the weight which, acting by 

 pressure alone, will produce the same effect as the blow, and it is 

 another thing of a widely different nature to determine what that effect 

 actually is. Any practical man at all acquainted with the nature of 

 pile driving, will at once scout the idea of being able to establish the 

 law, according to which a pile will actually sink by successive blows 

 of the ram ; because it is well known that the sinking of the pile is by 

 no means regular or proportioned to the friction opposing its descent 

 as determined by theory. On the contrary, in defiance of all theory, 

 a pile will sometimes sink more at the 4th or 5th blow, than at the 

 1st or 2nd, or perhaps more at the last blow than it did 10 or 15 blows 

 before ; and yet it is obvious that if we were attempting to investigate 

 theoretically the resistance of friction, we must estimate this resistance 

 to increase in some regular proportion to the depth to which the pile is 

 buried in the ground. 



Practice, however, shows that occasionally the resistance is less than 

 at a previous blow, when theory would point out that it is more. 

 We therefore reject from our consideration every attempt to deter- 

 mine the actual effect produced by the force which we are able to exert 

 on the pile. In fact, whether the blow produce any effect or not, the 

 force exerted is still the same, and this is all that theory can deter- 

 mine, because the sinking of the pile depends on conditions of te- 

 nacity and consolidation of the ground to be driven into, which are too 

 various and complicated ever to be capable of general expression in 

 the formulae of calculation. 



It is true that Belidor and other French engineers, in that ardent 

 spirit of investigation which leads them to build up theories on a 

 purely hypothetical basis, where a practical or experimental one is 

 impossible, have assumed the rate of consolidation of earth at each 

 successive foot below the surface, and then taking into account the 

 surface of the pile exposed to friction, have attempted to estimate 

 the rate at which the pile would sink with each blovf of the ram. 

 We doubt, however, whether practice would ever be found, in a single 

 instance, to confirm a theory so established ; at any rate we should 

 esteem the coincidence of the two almost miraculous, even if, in some 

 rare instance, they ever have agreed. — Apart, then, from all conside- 

 ration of the effect produced in sinking the pile, let us simply enquire 



