US1910939A - Apparatus for forming concrete piles in the ground - Google Patents

Description

May 23, 1933. c "rm- 30 1,910,939

APPARATUS FOR FORMING CONCRETE FILES IN THE GROUND Filed April 27 1928 llllllllllllllu 5'2: mrllllllll Inventor. Alberr C. Tircomb Patented May 23, 1933 a a -M E 1 PATENT OFFICE I ALBERT QTI'ICOMB, or NEWTON, MASSACHUSETTS mums FORFORMING conenn'rn. ruins IN THE GROUND Application filed A ri1g27,

This invention relates to. improvements in method and apparatus for forming concrete piles in the groundfand' the object thereof is to provide a novel method and apparatus which will more efficiently produce thehole to receive the concrete which forms the pile and which willenable conerete piles to be properly constructed at a minimunrcost of material and labor.

In "usualprocesses of forming concrete piles inthe groundythe holeto receive the concrete is formed by driving into the ground a tubular forming member having a conical cast iron point having substantially the same maxinnun diameter as the diameter of the driving forniand provided with a shank which extends into, and substantially"fits, the lower end of the "driving "lorI'n. VVhenhthe driving form has been sunk until thefpoint encounter-5a rigidmw terialfor when the resistance to further driving exceedsa predetermined minimum force, the driving form is filled with concrete and tlielorm pulled out,additional concrcte being poured in, it necessary, during the extractionpf the form.

fIn soniecases previously castconical con crete points havebecn employed, and in others conical concrete points armored with a fnietallie shell, or expensiveeast steel pointshave been used i When in the use of such apparatus the drivingf form isforced through a stratum eontaining stones of considerable size the clinical metallic or other "points are frequently broken and great, difiiculty; there after encountered in properly sinking the form to a suflicient depth to give the pilea suitable foundation.

a driving point of the charaeter specified, having the same diameteras thatof the driving form, isdriven through a stratum of this character the formj Wlll become wedged betweendarge pieces rock so that it can bewithdrawn 1928, Serial No. 273,219.

only with great difiiculty and in many instances requiring the use of a water jet to shift the location oftherock. Again, concrete piles are frequently i e-Q quired to be driven among old wood piles and where a conical point, such as above described, of approximately the same size of the driving form, employed and driven among such old piles, the removal ofthe form, after it has been filled with concrete, has proved very diflieultandsome times inipossiblei I Ly Y i The present invention is designed to overcome these and other difliculties' which are encountercdin the production of con cretepiles inthe ground. i The'method offorming concrete piles in the grormd, inaccordance with my invention, comprises driving into thelground a preparatory pile having at its lower end a detachable, substantially fiat, infrangible metallic driving head of greater area than the area of the lower end of said form, then filling the chamber of the form, to a greater or less degree, withconcrete and withdraw etrating heads a suitable foundation for the pile may be made upon strata of sand, or other material, which would not properly supporta :pile having as va footing the conical penetrating point. t a

By employing a flat penetrating point of this character, whiclris of larger diameter than the diameter ofthe driving form, the

driving form can be readily withdrawn after having been filled with concrete, thereby affecting a great saving in time and labor over usual methods.

Usual types of cast iron conical points for driving forms heretofore employed are of very considerable weight approximating one hundred pounds each. In the present invention the penetrating head, which is in the form of a substantially flat infrangible steel plate preferably having a peripheral flange surrounding the lower end of the driving form, is much lighter, such flat penetrating heads weighing approximately forty pounds having been successfully employed without breakage under conditions which caused frequent breakage of the heavier cast iron conical heads. Y

The production of such fiat penetrating heads is relatively inexpensive and a considerable saving in cost of transportation is effected where large numbers of concrete piles are being formed.

Such flat heads are of greater effective area than the conical heads and give a greator bearing surface which in some soils permits the use of a much shorter pile, thus decreasing the cost of thepile. Furthermore, the flat surface of the head in many soils gives a better bearing, for example, where piles are driven to'hard material which cannot be penetrated by the conical point more than aninch or two, the bearing surface on the hard material is very limited, where as with the flat surface of the penetrating head embodying the present invention the whole area of the head is in contact with the hard material thus giving a greater faetor of safety.

A preferred form of apparatus embodying the present invention is illustrated in the accompanying drawing, in which,

Fig. l is arvertical sectional View of a driving form having a flat metallic, preferably steel, penetrating head thereupon and sunk into the ground;

Fig. 2 is a detail View of the same showing a packing between the junction of the lower end of the driving form and a flat penetrating head, the packing being onclosed. within the flange of the head which surrounds the lower end of the driving form;

Fig. 8 is a sectional view on line 3-3 Fig. 2, viewed downwardly, a portion of the wall of the. form being broken away to illustrate the preferred form of packing which is in the form of a coiled rope packed with grease; V

Fig. 4 is a detail vertical sectional view of a concrete pile formed in accordance with the present invention, the fiat penetrating head forming a footing for the pile;

Fig. 5 is a detail vertical sectional view of a slightly modified form of substantially diameter or area than that of the lower end of the driving form. The penetrating head 2 is provided with means presenting a shoulder to prevent undue lateral displacement relatively to the lower end of the driving head. In the particular form illustrated the driving head has an upwardly extending peripheral flange 3 which surrounds the lower end of the driving tube.

' In the use of the apparatus described the penetrating head 2 may be placed upon the soil at the spot where the pile is to be driven, the driving form 1 superimposed thereupon within the peripheral flange 3, and a suitable block or head placed upon the upper end of the driving form, and the form forced downwardly by blows, hydraulic pressure, or otherwise, as is usual.

It is found in actual practice that where stones or rocks are encountered by the driving head, the engagement with such rocks is such that they will be generally forced laterally out of the path of the driving form.

Inasmuch as the head 2 is of reater area than the area of the lower end of the driving form, the rocks will thus be forced laterally a suiiicient distance to prevent wedging against the wall of the driving form so that the driving form may be readily withdrawn after the form has been driven to such depth that the head engages an impenetrable medium, or engages a stratum affording the required degree of resistance to further driving.

When the form has thus been driven down it is filled with concrete and withdrawn in the usual manner, the concrete, after withdrawal of the form, filling the hole produced by the apparatus above described. The head. which is, of course, detachable from the driving form, remains at the lower end ofthe hole and forms a flat footing for the concrete with the peripheral flange enclosing the lower end of the concrete pile. This flat footing provides a more even distribution of the strains imposed upon the pile when a structure is superimposed upon it and consequently provides a much firmer foundation than that which would be provided by a conical point, the effective area of the supporting portion of which is fremeans shall be provided to prevent accumulation of water within the driving form dur ing the driving thereof as such water would otherwise have to be removed before the concrete is poured into the pile in order to insure a proper consistency of concrete at the lower end of, or throughout, the pile.

Thepresent invention permits a proper water-tightseal between the lower end of the driving form and the head to be employed as the sealing mechanism will be properly retained within the peripheral flange which surrounds the lower end of the driving form.

Apacking of fibrous material containing a water-repellant substance is employed. A preferred packing, which is illustrated in Figs. 2 and 3, comprises a coil of rope 4L thoroughlyimpregnated with heavy grease, the rope being coiled in a flat spiral within the flange 3 and preferably extending beneath the lower end of the driving member as illustrated in Fig. 2. 7

Other forms of substantially flat penetrating heads are illustrated in Figs. 5 and 6.

In the construction illustrated inFig. 5 the substantially flat plate, which forms the penetrating head, has an annular flat portion 5 while the central portion 6 is convexedly curved downwardly.- The plate is provided with a peripheral flange 3 to enclose the lower end ofthe driving member as above described. p

i In the construction illustrated in Fig. 6

the substantially flat penetrating head presents an annular flat portion 7 and a central, slightly conical,portion 8. In this form, as in theother, the J'enetrating head is pro vided with the peripheral flange 3 which encloses the lower end of the driving form. In both of these constructions the lower end of the driving form rests upon the flat annular portion of the head.

It has been found in practice that where substantially flat infrangible steel plates are employed for penetrating heads, plates of considerably less thickness than the thickness of the wall of the driving form may be successfully used.

As a matter of fact, steel plates having a thickness of three-eighths inch and provided with peripheral flanges have been successfully employed. as penetrating heads for driving forms the walls of which are threefourths inch in thickness, and driving forms having such heads have been successfully driven in soil conditions in which it was quite impossible to drive similar forms havwhich 'illustmtes a concrete pile produced 3 after a. driving form had been sunk through thesoil condition, comprising a fill A of several feet, witha sand stratum B therebeneath varying in thickness, with a clay stratum C therebeneath. In driving the form for this pile: rocks D were encountered which were forced laterally from the path of the driving form by thewlarger head of the pile. When the flat driving head had reached the stratum B of sand itpresented a sufficient area properly to support the pile, where with usual conical points the supporting area in certain portions of the sand stratum was of insuflicient thickness to provide suitable resistance requiring the use of a pile several feet longer than that which was required for piles having the flat footing provided by the flat penetrating head embodying the present invention.

It has been found that the cost of constructing concrete piles with forms having flat steel penetrating heads is considerably tion. Furthermore, the delay occasioned by damage to the driving form increases the ultimate cost of the pile. Where the present invention isemployed no such breakage of the penetrating head has been found to occur under any conditions of service.

It will be understood that the embodiment ofthe invention disclosed herein is of an illustrative character and is not restrictive, and that the term substantially flat is in tended to embrace not only constructions such as are illustrated in the drawing, but other equivalent constructions adapted for the same purpose and operating in alike manner.

Having thus described the invention, what is claimed as new, and desired to be secured by Letters Patent, is:

1. An apparatus for forming concrete piles in the ground comprising a cylindrical driving form, a substantially flat steel penetrating head, of greater area than that of the lower end of said driving form, engaging the lower end of said driving form and having a peripheral flange enclosing said lower end and spaced apart therefrom, and a yieldable packing of fibrous material containing a water-repellant substance within said flange.

2. An apparatus for forming concrete piles inthe ground comprising a cylindrical driving form, a substantially flat steel pene- ALBERT C. TITCOMB.

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