PILES

, in Building, are large stakes, or beams, sharpened at the end, and shod with iron, to be driven into the ground, for a foundation to build upon in marshy places.

Amsterdam, and some other cities, are wholly built upon Piles. The stoppage of Dagenham-breach was effected by dove-tail Piles, that is by Piles mortised into one another by a dovetail joint.

Piles are driven down by blows of a large iron weight, ram, or hammer, dropped continually upon them from a height, till the Pile is sunk deep enough into the ground.

Notwithstanding the momentum, or force of a body in motion, is as the weight multiplied by the velocity, or simply as its velocity, the weight being given, or constant; yet the effect of the blow will be nearly as the square of that velocity, the effect being the quantity the Pile sinks in the ground by the stroke. For the force of the blow, which is transferred to the Pile, being destroyed, in some certain definite time, by the friction of the part which is within the earth, which is nearly a constant quantity; and the spaces, in constant forces, being as the squares of the velocities; therefore the effects, which are those spaces sunk, are nearly as the square of the velocities; or, which is the same thing, nearly as the heights fallen by the ram or hammer, to the head of the Pile. See, upon this subject, Leopold Belidor, also Desaguliers's Exper. Philos. vol. 1, pa. 336, and vol. 2, pa. 417: and Philos. Trans. 1779, pa. 120.

There have been various contrivances for raising and dropping the hammer, for driving down the Piles; some simple and moved by strength of men, and some complex and by machinery; but the completest PileDriver is esteemed that which was employed in driving the Piles in the foundation of Westminster bridge. This machine was the invention of a Mr. Vauloue, and the description of it is as follows.

Description of Vauloue's Pile-Driver. See fig. 2, pl. xx. A is the great upright shaft or axle, carrying the great wheel B and drum C, and turned by horses attached to the bars S, S. The wheel B turns the trundle X, having a fly O at the top, to regulate the motion, and to act against the horses, and keep them from falling when the heavy ram Q is disengaged to drive the Pile P down into the mud &c. in the bottom of the river. The drum C is loose upon the shaft A, but is locked to the wheel B by the bolt Y. On this drum the great rope HH is wound; one end of it being fixed to the drum, and the other to the follower G, passing over the pulleys I and K. In the follower G are contained the tongs F, which take hold of the ram Q, by the staple R for drawing it up. D is a spiral or fusee fixed to the drum, on which winds the small rope T which goes over the pulley U, under the pulley V, and is fastened to the top of the frame at 7. To the pulleyblock V is hung the counterpoise W, which hinders the follower from accelerating as it goes down to take hold of the ram: for, as the follower tends to acquire velocity in its descent, the line T winds downwards upon the fusee, on a larger and larger radius, by which means the counterpoise W acts stronger and stronger against it; and so allows it to come down with only a moderate and uniform velocity. The bolt Y locks the| drum to the great wheel, being pushed upward by the small lever 2, which goes through a mortise in the shaft A, turns upon a pin in the bar 3 fixed into the great wheel B, and has a weight 4, which always tends to push up the bolt Y through the wheel into the drum. L is the great lever turning on the axis m, and resting upon the forcing bar 5, 5, which goes down through a hollow in the shaft A, and bears upon the little lever 2.

By the horses going round, the great rope H is wound about the drum C, and the ram Q is drawn up by the tongs F in the follower G, till they come between the inclined planes E; which, by shutting the tongs at the top, open them below, and so discharge the ram, which falls down between the guide posts bb upon the Pile P, and drives it by a few strokes as far into the ground as it can go, or as is defired; after which, the top part is sawed off close to the mud, by an engine for that purpose. Immediately after the ram is discharged, the piece 6 upon the follower G takes hold of the ropes aa, which raise the end of the lever L, and cause its end N to descend and press down the forcing bar 5 upon the little lever 2, which, by drawing down the bolt Y, unlocks the drum C from the great wheel B; and then the follower, being at liberty, comes down by its own weight to the ram; and the lower ends of the tongs slip over the staple R, and the weight of their heads causes them to fall outward, and shuts upon it. Then the weight 4 pushes up the bolt Y into the drum, which locks it to the great wheel, and so the ram is drawn up as before.

As the follower comes down, it causes the drum to turn backward, and unwinds the rope from it, while the horses, the great wheel, trundle, and fly, go on with an uninterrupted motion: and as the drum is turning backward, the counterpoise W is drawn up, and its rope T wound upon the spiral fusee D.

There are several holes in the under side of the drum, and the bolt Y always takes the first one that it finds when the drum stops by the falling of the follower upon the ram; till which stoppage, the bolt has not time to slip into any of the holes.

The peculiar advantages of this engine are, that the weight, called the ram, or hammer, may be raised with the least force; that, when it is raised to a proper height, it readily disengages itself and falls with the utmost freedom; that the forceps or tongs are lowered down speedily, and instantly of themselves again lay hold of the ram, and lift it up; on which account this machine will drive the greatest number of piles in the least time, and with the fewest labourers.

This engine was placed upon a barge on the water, and so was easily conveyed to any place desired. The ram was a ton weight; and the guides b, b, by which it was let fall, were 30 feet high.

A new machine for driving piles has been invented lately by Mr. S. Bunce of Kirby-street, Hatton-street, London. This, it is said, will drive a greater number of Piles in a given time than any other; and that it can be constructed more simply to work by horses than Vauloue's engine above described.

Fig. 3 and 4, plate xx, represent a side and front section of the machine. The chief parts are, A, fig. 3, which are two endless ropes or chains, connected by cross pieces of iron B (fig. 4) corresponding with two cross grooves cut diametrically opposite in the wheel C (fig. 3) into which they are received; and by which means the rope or chain A is carried round. FHK is a side-view of a strong wooden frame moveable on the axis H. D is a wheel, over which the chain passes and turns within at the top of the frame. It moves occasionally from F to G upon the centre H, and is kept in the position F by the weight I fixed to the end K. In fig. 5, L is the iron ram, which is connected with the cross pieces by the hook M. N is a cylindrical piece of wood suspended at the hook at O, which by sliding freely upon the bar that connects the hook to the ram, always brings the hook upright upon the chain when at the bottom of the machine, in the position of GP. See fig. 3.

When the man at S turns the usual crane-work, the ram being connected to the chain, and passing between the guides, is drawn up in a perpendicular direction; and when it is near the top of the machine, the projecting bar Q of the hook strikes against a cross piece of wood at R (fig. 3); and consequently discharges th<*> ram, while the weight I of the moveable frame instantly draws the upper wheel into the position shewn at F, and keeps the chain free of the ram in its descent. The hook, while descending, is prevented from catching the chain by the wooden piece N: for that piece being specisically lighter than the iron weight below, and moving with a less degree of velocity, cannot come into contact with the iron, till it is at the bottom, and the ram stops. It then falls, and again connects the hook with the chain, which draws up the ram, as before.

Mr. Bunce has made a model of this machine, which performs perfectly well; and he observes, that, as the motion of the wheel C is uninterrupted, there appears to be the least possible time lost in the operation.

Pile is also used among Architects, for a mass or body of building.

, in Artillery, denotes a collection or heap of shot or shells, piled up by horizontal courses into either a pyramidal or else a wedge-like form; the base being an equilateral triangle, a square, or a rectangle. In the triangle and square, the Pile terminates in a single ball or point, and forms a pyramid, as in plate xix, fig. 4 and 5, but with the rectangular base, it finishes at top in a row of balls, or an edge, forming a wedge, as in fig. 6.

In the triangular and square Piles, the number of horizontal rows, or courses, or the number counted on one of the angles from the bottom to the top, is always equal to the number counted on one side, in the bottom row. And in rectangular Piles, the number of rows, or courses, is equal to the number of balls in the breadth of the bottom row, or shorter side of the base<*> also, in this case, the number in the top row, or edge, is one more than the difference between the length and breadth of the base. All which is evident from the inspection of the figures, as above.

The courses in these Piles are figurate numbers.

In a triangular Pile, each horizontal course is a triangular number, produced by taking the successive sums of the ordinate numbers, viz,|

And the number of shot in the triangular Pile, is the sum of all these triangular numbers, taken as far, or to as many terms, as the number in one side of the base. And therefore, to find this sum, or the number of all the shot in the Pile, multiply coutinually together, the number in one side of the base row, and that number increased by 1, and the same number increased by 2; then 1/6 of the last product will be the answer, or number of all the shot in the Pile.

That is, is the sum; where n is the number in the bottom row.

Again, in Square Piles, each horizontal course is a square number, produced by taking the square of the number in its side, or the successive sums of the odd numbers, thus, .

And the number of shot in the square Pile is the sum of all these square numbers, continued so far, or to as many terms, as the number in one side of the base. And therefore, to find this sum, multiply continually together, the number in one side of the bottom course, and that number increased by 1, and double the same number increased by 1; then 1/6 of the last product will be the sum or answer.

That is, is the sum.

In a rectangular Pile, each horizontal course is a rectangle, whose two sides have always the same difference as those of the base course, and the breadth of the top row, or edge, being only 1: because each course in ascending has its length and breadth always less by 1 than the course next below it. And these rectangular courses are found by multiplying successively the terms or breadths 1, 2, 3, 4, &c, by the same terms added to the constant difference of the two sides d; thus, .

And the number of shot in the rectangular Pile is the sum of all these rectangles, which, it is evident, consist of the sum of the squares, together with the sum of an arithmetical progression, continued till the number of terms be the difference between the length and breadth of the base, and 1 less than the edge or top row. And therefore, to find this sum, multiply continually together, the number in the breadth of the base row, the same number increased by 1, and double the same number increased by 1, and also increased by triple the difference between the length and breadth of the base; then 1/6 of the last product will be the answer.

That is, is the sum. where b is the breadth of the base, and d the difference between the length and breadth of the bottom course.

As to incomplete Piles, which are only frustums, wanting a similar small Pile at the top; it is evident that the number in them will be found, by-first computing the number in the whole Pile, as if it were complete, and also the number in the small Pile wanting at top, both by their proper rule; and then subtracting the one number from the other.

In piling of shot, when room is an object, it may be observed that the square Pile is the least eligible, of any, as it takes up more room, in proportion to the number of shot contained in it, than either of the other two forms; and that the rectangular Pile is the most eligible, as taking up the least room in proportion to the number it contains.