US3001515A - Method of driving piles - Google Patents

Description

Sept. 26, 1961 K. HAAGE METHOD OF DRIVING PILES 2 Sheets-Sheet 1 Filed April 20. 1959 AVVE/l/TOP z r aa/ flee we Sept. 26, 1961 K. HAAGE 3,001,515

METHOD OF DRIVING FILES Filed April 20. 1959 2 Sheets-Sheet 2 3,001,515 METHOD OF DRIVING PILES Kom'ad Haage, Esslingen-Kirnmichsweiler, Germany, as-

signor to Firma Delmag-Machinenfabrik Reinhold Dornfeld, Esslingen (Neckar), Germany Filed Apr. 20, 1959, Ser. No. 807,674 Claims priority, application Germany Apr. 26, 1958 1 Claim. (Cl. 123-7) The present invention relates to a method of pile driving and a pile driver. With heretofore known pile drivera, the driving of piles and the like is effected exclusively by blows. However, the driving of piles and the like by blows has various drawbacks. Thus, for instance, such blows cause very high forces of inertia which are effective for an extremely short time only and which harmfully affect the material of the pile driver as well as of the pile being driven. On the other hand, a considerable shock loss is encountered which produces heat and plastic deformation and likewise has a destroying effeet. It may also be added that the hard blow causes considerable noise which is audible for quite a distance and is a considerable nuisance in residential districts.

With heretofore known diesel hammers with which the blow effect during the driving of the pile is aided by the high combustion pressure, the advancement of the pile stops only after the carrying capacity of the pile has reached six to seven times the maximum combustion pressure. If such a hammer would work with the combustion pressure only, in other words, if the blow effect would not be used, the advancement of the pile would cease when its carrying capacity has reached 0.6 to 0.7 the maximum combustion pressure.

It is an object of the present invention so to modify the driving operation that it would be possible not to use the blow effect without encountering the premature ceasing of the penetration of the pile, thereby avoiding the above mentioned drawbacks due to the blow or hammer effect.

It is another object of this invention so to conduct the driving operation of a diesel hammer that the driving of the pile will be effected by the combustion pressure only.

Another object consists in the provision of an improved pile driver.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawing, in which:

FIG. 1 is a vertical sect-ion through a hammer of a diesel hammer, said hammer occupying its highest position.

FIG. 2 is a section similar to that of FIG. 1 but with the hammer occupying its lowest position in which it exerts the highest pressure on the pile to be driven.

The method according to the invention of driving a pile or the like by means of a high pressure diesel hammer is characterized primarily in that the driving operation is efiected without a hammer efiect and exclusively by means of the combustion pressure of the diesel hammer in such a way that by correspondingly dimensioning the piston surface, the combustion pressure is increased at least up to the maximum desired carrying capacity of the pile to be driven the counter pressure of the combustion gases enclosed in the compression chamber being absorbed by the dropping mass of the hammer which without blow upon the pile is again accelerated in upward direction.

This method may be carried out by employing a hammer having a piston surface of such magnitude that the maximum combustion pressure acting thereupon will be approximately from 1.4 to 2.5 times higher, than the r Patented Sept. 26, 19 61 ice maximum carrying capacity required by the pile to be driven. By selecting the combustion pressure, i.e. the specific combustion pressure in atmospheres above at-: mospheric pressure multiplied by the piston surface, of such magnitude that the said combustion pressure alone, i.e. without a blow exerted by the hammer upon the pile, can drive the pile until the desired carrying capacity of the pile has been obtained, the goal of-the invention is assured. The pile may thus be driven, at least up to this time, without hammer blows. -In addition to the requirement that the combustion pressure is supposed to be approximately from 1.4 to 2.5 times as great as the maximum required carrying capacity of the pile, the combustion pressure also meet the requirement that it will be effective for such a time that during such a combustion, the stroke performed by the pile head will during this period be greater than the elastic resiliency of the pile and of the ground at said load. The. farther the combustion pressure exceeds the maximum carrying capacity of the pile, the less may be the duration of the combustion pressure effect, and vice versa.

The increase in the specific pressure of the explosion gases alone would not lead to the desired goal of effecting the drive without blows because in such an instance the maximum combustion pressure with the nowadays customary stroke volumes and the customary ratios of stroke to diameter would have to increase to up from 500 to 800 atmospheres above atmospheric pressure, whereas 300 atmospheres above atmospheric pressure is nowadays the feasible limit of pressures occurring with diesel hammers. 1

The piston surface should therefore be of a magnitude which equals about 1.7 to 3.0 that of diesel hammers of the same output. Since on the other hand, the stroke volume can be enlarged only slightly, because otherwise the jumping height of the hammer will become so great with only slightly pulling piles that again a blow will occur, the stroke may be reduced correspondingly so that a very short stroke machine will be created in which the quotient of stroke to piston diameter varies in instance from about 0.7 to 0.2, preferably from 0.5 to 0.3.

With reference to the drawing, the cylinder simultaneously serving as hammer is guided on a shaft 3 by means of a guiding slide 2. Piston 4 having a diameter D rests through a blower hood 5 upon a pile 6. A fuel tank 7 is arranged in the upper portion of cylinder 1 and surrounds a fuel injection pump 8 which injects fuel into chamber 10 through the intervention of an injection nozzle 9. The explosion gases are adapted to escape from this chamber through control slots 11 through which control slots also fresh air is adapted to be drawn Cylinder 1 driving upwardly by explosion pressure is shown in FIG. 1 in its highest flying position.

FIG. 2 which also shows the stroke h shows the condition in which the cylinder has dropped to such an extent that the piston has overrun the control slots 11 and is now located in its highest (innermost) position at which the compression has reached its maximum. Shortly prior thereto, the fuel was injected which now is ignited in view of the high compression temperature. The thus resulting high combustion pressure P acts upon piston 4 which latter through connecting rod 41 and blower hood 5 drives pile 6 into the ground because the combustion pressure -P is higher than the resistance W of the pile to penetration. The combustion pressure acts upon the cylinder 1 and accelerates its mass and thereby throws said mass upwardly whereupon a new cycle will start. A contact between cylinder 1 and the blower hood 5 will not occur with this operation.

It is a well-known fact that diesel hammers with high compression pressures start rather reluctantly at the i a V I 3 I beginning of the pile driving operation, i.e. when the pile has-still a very low driving resistance. Therefore, it had to be ascertained whether the pile driving without blow would become impossible by the fact that a pile driver according to the invention very large piston' sufiac'e and very high compression "and combustion 'pressures insight at all start or continue running "when the drining of such light pile. However, it

has been found that the behavior :of the engine "as far as 'its 'stazrtin'g is "C'Q'l'ltfiined does not :tl'epend alone on the piston surface but also on the stroke volume. inasnm'ch a's, however, the stroke volume is not materially difierent-over the heretofore fknown pile drivers, a star in'g will he assured with the :method according to the invention and-the hamme'rs required -therefor.

----A's "will be evident from the above, with the method according to the invention, the 'piles are driven by pure pressure as if they were pressed hydraulically. The essential difierence cmisists in that when hydraulically pressing or driving, a counter bearing to be present which is adapted to absorb -the required high pressure. In contrast thereto, with the method according 'to the invention, exclusively the dropping hammer which, without the exertion of a thlowupon the pile is then :acc'elerated in upward direction, will serve as counter bearing.

It is, of course, to be understood that the present 1 invention is, by 'no means, limited to the particular on struction shown in the drawings but also comprises any modifications within the scope of the appended claim.

What I claim is: 7

A high pressure diesel driver for driving a pile by combustion pressure only, which includes .a having an effective :piston and a piston nodsqaroided with apfle-engaging member, and which also includes a cylinder receiving said piston, said cylinder being movable with respect to said piston, said effective piston surface confining with said cylinder a compression and combustion chamber, in which pile driver :the stroke of the cylinder relative to said piston divided by the piston diameter is within the range of .from 0,7 to 0.2.

473,295 Great Britain Oct. '11, 4937?

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