US3327483A - Pile driving mandrel construction and method for driving extensible piles - Google Patents

Description

I H. DE R. GIBBONS Fume E967 FILE DRIVING MANDREL CONSTRUCTION AND 33232483 METHOD FOR DRIVING EXTENSIBLE PILES Filed Oct. 2, 1964 2 Sheets-Sheet l I N VE TOR. Hurry ole R. Mwltwns ATTGIRNEYS June 27, 1967 H. DE R. GIBBONS 3,327,483

FILE DRIVING MANDREL CONSTRUCTION AND METHOD FOR DRIVING EXTENSIBLE FILES Filed Oct. 2, 1964 "2 Sheets-Sheet INVENTOR. Hayrry ale R; abbbons 9 W, W 8 Jam ATTORNEYS United States Patent PILE DRIVING MANDREL CONSTRUCTION AND METHQD FOR DRIVING EXTENSIBLE PHLES Harry de R. Gibbons, North (Ianton, @hio, assignor to The Union Metal Manufacturing Company, Canton,

Ohio, a corporation of Ohio Filed Oct. 2, 1964, Ser. No. 400,996 7 Claims. (Cl. 6153.7)

The invention relates to piles, and more particularly to the driving and forming of piles in which a tapered tubular metal shell is driven into the ground with a tapered, substantially rigid, driving mandrel or core, and the tapered shell being driven is used to pull sheet metal shell extension sections into the ground above and connected to the tapered shell, and in which the mandrel then is extracted from the shell sections and the latter are filled with suitable bearing material, preferably concrete, to form the pile; and the present invention constitutes improvements on the invention set forth in the copending Gibbons and Rausch application S.N. 398,291, filed Sept. 22, 1964, entitled, Pile Driving Mandrel Construction and Method.

The copending application illustrates, describes and claims a mandrel construction which solves many problems and eliminates many difiiculties heretofore encountered in the art. Such mandrel construction includes a substantially rigid, longitudinally continuous mandrel member having a head and a tapered shell-contacting portion, ring means surrounding the upper end of the mandrel spaced below the head and engageable with the upper end of a tapered tubular pile shell being driven when the tapered mandrel portion is telescoped within such shell, and a driving cap releasably telescoped over and engaged with the mandrel head and spaced from the ring means initially driving the mandrel to penetrate the shell with the cap thereafter engaging the ring means for simultaneously driving the heads of the mandrel and shell.

A tapered shell of one length, top diameter and taper normally will be driven by a tapered mandrel of one particular or standard size, as shown in said copending application. Ordinarily, a large number of pile shells may be driven at a particular driving site for the foundations of a bridge, building, and the like. When conditions are ideal, substantially all pile shells driven at the same site may have approximately the same driven length. Thus all pile shells supplied for a given job normally will have the same length and will be driven by the one standard mandrel for such shells. If some of the shells when driven are too long, the top ends of the shells when formed of metal may be cut oil? with a torch, and no real problem is presented.

Situations arise, however, where the pile shells being driven are shorter than required, or where the known length of the required pile is considerably longer than standard tapered pile shells immediately available, or where special tapered mandrels required for longer tapered shells are not immediately available, or where extremely long piles are required which involve a plurality of metal shell sections that must be joined together end to end either before or during driving.

In such situations, a standard length tapered shell may serve adequately as a bottom portion of a driven shell, provided that such shell can be extended upwardly with additional shell sections of sufiicient length to provide the final required pile shell length.

Prior arrangements for driving a pile shell deeper than the initially driven shell section and which is extended by additional shell sections have involved driving the initial sect-ion with a mandrel that did not touch the sides of the section, then extracting the mandrel, and then insert- 3 ,327,483 Patented June 27, 1967 ing a heavy walled shell extension section which was top driven to the required depth. This procedure is undesirable in requiring the expense of an extension section left in the ground having a heavy enough wall to stand up under the blows of the pile driving hammer.

Other arrangements have involved the use of a heavy walled driving extension to sink the initial nose section deeply in the ground, after which a thin walled shell extension section of corrugated culvert-like form is dropped within the heavy walled driving extension member to provide the shell extension for the nose section, and then the heavy walled driving extension member is'pulled out of the ground for reuse. This arrangement while using a thin walled shell extension section also has dis-advantages involved with the pulling of the heavy walled driving member, with ground cave-ins related to the pulling operation, and with the non-uniformity of ground contact with the thin walled shell after the heavy walled member is pulled.

Accordingly, it is a general object of the present invention to provide a mandrel and pile shell construction with which a tapered shell section can be driven into the ground utilizing the improved mandrel construction and method of said copending application, and with which the driven tapered section can be extended upwardly by additional thin gauge metal extending sections pulled into the ground by the tapered section as the tapered section continues to be driven deeper and deeper into the ground for the desired or required distance.

Furthermore, it is an object of the present invention to provide an improved means and procedure for driving extensible piles.

In addition, it is an object of the present invention to provide a new mandrel construction and driving procedure by which an extensible pile shell may be driven into the ground comprising a tapered preferably fluted lower shell section having a shoulder at its upper end to which extending sections are connected and pulled into the ground by the tapered section as the latter is driven, in which the extending sections may be formed of light gauge material that cannot withstand the application of direct driving forces, and in which the extending sections may have any shape, thickness or diameter and normally will not be tapered.

Furthermore, it is an object of the present invention to provide a new mandrel and pile shell construction and driving procedure with which light gauge pile shells of various lengths involving light gauge extension sections that cannot withstand direct driving blows may be driven into the ground using only one special mandrel and one size of tapered pile shell section, thereby substantially reducing the investment in driving equipment necessary for driving pile shells regardless of the penetrated depth and reducing the cost of the driven piles by eliminating the necessity of using heavy walled shell sections, while at the same time assuring proper bearing contact between the shell sections and the ground into which the shell sections are driven.

Finally, it is an object of the present invention to pro vide a new pile driving mandrel construction and procedure for driving extensible thin walled tubular pile shells, eliminating difficulties heretofore encountered in the art; eliminating complicated and costly mandrel and shell structures; achieving the indicated objects in a combined, simple, effective and inexpensive manner; and solving problems and satisfying needs existingin the art.

These and other objects and advantages apparent to those skilled in the art from the following description and claims, may be obtained, the stated results achieved, and the described dificulties overcome, by the apparatus, combinations, parts, elements, subcombinations, arrangements, relationships, constructions and methods which comprise the present invention, the nature of which are set forth in the following general statements, a preferred embodiment of whichillustrative of the best mode in which applicant has contemplated applying the principles-is set forth in the following description and shown in the drawings, and which are particularly and distinctly pointed out and set forth in the appended claims forming part hereof.

The nature of the improved apparatus for setting piles of the present invention may be stated in general terms as including a tapered tubular, preferably longitudinally fluted, ribbed or corrugated sheet metal pile shell section having a nose and an upper end; connection ring means connected to the upper end of said tapered shell section formed with shoulder means; a thin gauge tubular sheet metal pile shell extension section connected to said connection ring means and extending upwardly therefrom; a substantially rigid longitudinally continuous main mandrel member having a head portion with an upper end and a tapered shell-contacting portion, the tapered mandrel portion being shorter than the tapered shell section and being tapered selectively on the same or slightly greater taper than that of the tapered shell section; a supplemental or secondary heavy-walled tubular, preferably cylindrical, mandrel member telescoped over and surrounding the head portion of the main mandrel member and being located within the thin gauge shell extension section having a lower end resting on the connection ring shoulder means and having an upper end located adjacent the upper end of the main mandrel head portion; mandrel and shell-engaging and driving cap means releasably telescoped over and engaged with the upper end of the main mandrel head portion, the tapered mandrel portion when telescoped within the tapered shell section before driving with the cap means engaged with the main mandrel head having the cap means spaced above the upper end of the secondary mandrel; means for establishing driving engagement between the cap means and the upper end of the secondary mandrel after the tapered mandrel portion has been driven into the tapered shell section to penetrate said shell section a predetermined distance; the tapered mandrel portion frictionally wedge-engaging and slightly radially expanding the tapered shellsection during the predetermined penetration of the shell section by the tapered mandrel portion; the cap means when driving engagement is established with the upper end of the secondary mandrel member, also top driving the tapered shell section through said connection ring shoulder means into the ground by blows applied to said cap means; and said frictionally engaged and top-driven tapered shell section pulling said shell extension section into the ground until the shell sections are driven to the desired depth.

The nature of the improved method of driving into the ground extensible pile shells composed of thin-walled tapered and thin-walled tubular shell extension sections in accordance with the invention may be stated in general terms as including the steps of telescoping a downwardly inwardly tapered portion of a substantially rigid longitudinally continuous mandrel having a head at one end and a nose at the other end into a tapered tubular sheet metal pile shell section also having a shoulder at one end; a nose at the other end and a thin gauge tubular pile extension section extending upwardly from the shoulder; then driving the mandrel relatively into the tapered shell section to penetrate said shell section and frictionally wedge-engage tapered telescoped contacting surfaces of said mandrel and tapered shell section to establish frictional driving contact therebetween; controlling the penetration of the tapered mandrel portion in the tapered shell section to a predetermined amount; then after such predetermined penetration simultaneously driving the tapered shell section head and mandrel head to drive the tapered shell section into the ground to the Al desired depth; and pulling the thin gauge tubular shell extension section into the ground by the driving of the tapered shell section.

By way of example, an embodiment of the improved mandrel construction and extensible pile shell driving procedure is shown in the accompanying drawings forming part hereof in which:

FIGURE 1 is a side elevation with parts broken away and in section illustrating the improved construction with the shell sections to be driven telescoped over the mandrel components at the beginning of a driving operation;

FIG. 2 is a side view of the parts shown in FIG. 1 i1- lustrating the mandrel and shell components during driving after a predetermined penetration of the tapered FIG. 5 is an enlarged sectional view taken on the line 55, FIG. 1;

FIG. 6 is a plan View with parts in section of the parts shown in FIGS. 1 and 3; and

FIG. 7 is a section looking in the direction of the arrows 7-7, FIG. 4.

Similar numerals refer to similar parts throughout the various figures of the drawings.

A tapered tubular pile shell is indicated generally at 1 and preferably is formed of light gauge sheet or strip metal such as 11 gauge strip steel. The pile shell 1 has a connection ring generally indicated at 2 secured to the upper end 3 of tapered shell 1, and pile shell extension sections generally indicated at 4 are connected to connection ring 2.

The tapered shell section 1 is adapted to be driven into the ground and to pull the extension sections 4 into the ground as the tapered section 1 is driven. When the pile shell sections 1 and 4 have finally been driven to the proper position, they may be filled with concrete to form a pile.

Shell 1 preferably is provided with a closed lower end or nose 5 and preferably also is provided with longitudinally continuous outturned flutes 6 which not only reinforce or stiffen shell 1 but serve other purposes to be described.

Shell 1 may have any desired length and because .of its taper, it readily penetrates the ground. and may, therefore, readily be driven to desired depth. Shell 1 in accordance with the invention preferably has a standard length, as for example, 30 feet in length, and may be used to pull extension sections 4 of varying lengths into the ground to serve as shells for piling required to be driven to various depths. However, since the tapered section 1 is standardized, the driving mandrel for the tapered section also may be standardized so that only one mandrel construction normally is required for driving extensible pile shells of various lengths.

Pile shell section 1 may be driven by usual pile driving equipment, not shown, which may include a hammer and head guide 7 supported in a usual manner on the driving equipment and a reciprocating hammer plunger 8.

A mandrel generally indicated at 9 may be used for driving the tapered shell section 1 and the extension section 4 into the ground, the lower portion 10 of mandrel 9 being tapered downwardly inwardly and being extended upwardly by preferably cylindrical mandrel portion 11 which forms the head portion of the mandrel terminating at an upper end 12. Head portion 11 and upper end 12 of mandrel 9 preferably may be constructed like the mandrel shown in said copending application to include an annular recess 13 on which a floating driving ring 14 is mounted for movement axially of the mandrel head portion 11 and up and down recess 13.

The upper end 12 of mandrel head portion 11 preferably is tapered slightly upwardly inwardly at 15 and may be closed by a welded-in head cap 16. Upper head end 12 also preferably is provided with an extractor bar 17 extending through member 11 and having laterally projecting ends 18 preferably formed with openings 19, the extractor bar 17 being located below head cap 16 and above recess 13 and floating drive ring 14 which surrounds recess 13.

A mandrel and shell engaging and driving cap generally indicated at 20 forms one of the components of the mandrel construction. The cap 20 preferably includes an upwardly extending cup-shaped sleeve 21 tapered at its upper end as indicated at 22. Cap 20 may be l-ashed to hammer guide 7 by cables 23 which extend through openings 24 formed in ears 25 projecting from cap 20 in the region of the cap member partition wall 26. A knockout plate 27, a cushion member 28, and an anvil 29 preferably are contained in the usual manner within the recess formed by cap sleeve 21 so that the blows of a hammer 8 are imparted to cap 20 through members 29, 28, and 27.

Driving cap 20 also is formed with a downwardly opening cup-shaped sleeve 30 having an annular lower end surface 31. Sleeve 30 is adapted to be telescoped over and engaged with the upper end 12 of mandrel head portion 11, the cavity formed by sleeve 30 preferably conforming in contour to the contour of the upper end 12 of mandrel head portion 11.

Sleeve 30 is formed with downwardly opening cutouts 32 which straddles the lateral projecting extractor bar ends 1 8 when sleeve 30 is telescoped over mandrel head portion 11 with the cap partition wall 26 engaged on the top end 12 of the mandrel as shown in FIGS. 1 and 2.

Cap member 20 when telescoped over and in driving engagement with top end 12 of head portion of mandrel 9, as shown in FIG. 1, has the end surface 31 of sleeve 30 spaced above floating ring 14 when the latter is at or adjacent its lower limit of floating movement along recess 13, as generally indicated in FIG. 1. When mandrel 9 is assembled with pile shell sections 1 and 4 to be driven, a secondary mandrel sleeve 33 is assembled therewith telescoped over and surrounding mandrel head portion 11 and engaged at its lower end 34 with connection ring 2 and adapted to be engaged at its upper end 35 by floating ring 14. Secondary mandrel sleeve 33 has a heavy rigid tubular wall which telescopically surrounds the head portion 11 of mandrel 9and extends telescopically within the pile shell extension section 4, as shown. The upper end 35 of secondary mandrel sleeve 33 is located above the upper end of shell extension section 4.

' When assembling the shell sections together preparatory to driving, the connector ring preferably is welded to the upper end 3 of tapered shell section 1 but may be secured thereto by any other suitable means. Connector ring 2 (FIG. 4) preferably has a ledge or shoulder portion,36 from which sleeve portion 37 projects downwardly within and is preferably welded to the upper end 3 of tapered shell section 4 for permanent connection thereto. Another sleeve member 38 projects upward from ledge portion '36 to which shell extension section 4 may be connected. As shown, shell extension section 4 is preferably a light gauge corrugated sheet metal member and may be formed of, say 18 gauge material generally having the shape of a corrugated culvert. The extension section 4, however, may be corrugated, round, or fluted in cross section and its thickness and diameter can vary depending on the ground conditions existing at the location where the piilng is to be driven. Furthermore, the extensi-on section 4 may have any desired length throughout its generally tubular extent. Also section 4 may comprise several pieces :axially connected together to provide the desired length. As shown, extension section 4 may be connected in any desired manner as by welding to sleeve 38 of connection ring 2 so that sleeve section 4 will be pulled into the ground as the tapered section 1 is driven.

Several operational steps in the use of the improved construction are illustrated in FIGS. 1, 2, and 3. When a shell 1 is to be driven along with a connection ring 2 and extension section 4, the mandrel 9 and supplementary mandrel sleeve 33 are telescoped into the shell sections, as shown in FIG. 1, with the lower tapered end 10 of mandrel 9 within the tapered shell section 9, with supplementary mandrel sleeve 33 resting at its lower end 34 on connection ring ledge 36, and with the upper ends 35 and 12 of sleeve 33 and mandrel head section 11, respectively, extending above the upper end of shell extension section 4. Driving cap 20 is lashed to the hammer guide 7, driving head sleeve 30 is telescoped over the upper end of mandrel head portion 11, and the entire assembly is suspended above the desired driving location ready to be driven. The parts, elements, and components at this time have the relative positions shown in FIG. 1 wherein the floating driving ring 14 rests on the top end of supplementary mandrel sleeve 33 which in turn rests at its lower end 34 on ledge 36 of connection ring 2.

Driving blows from hammer 8 through cap 20 drive mandrel head portion 11 engaged by cap 20 downward so that tapered portion 10 of mandrel 9 relatively penetrates tapered shell portion 1. Penetrating movement of mandrel 9 establishes frictional driving wedge-engagement between the tapered outer surface of tapered mandrel portion 10 and the ribs of shell flutes 6 along the telescoped and engaged portions of said tapered mandrel and shell portions. This frictional wedge-engagement slightly radially expands tapered shell 1 along its length as the tapered mandrel portion 10 penetrates tapered shell section 1. v

In accordance with the invention, the amount of axial wedge penetration of shell 1 by mandrel 9 and the amount of radial expansion of shell 1 is controlled such as to prevent shell bursting. Furthermore, tapered portion 10 of mandrel 9 is shorter in length than tapered shell section 1, as shown, and at no time does the lower end of the mandrel engage the nose 5 of shell 1. The controlled mandrel-shell penetration is predetermined to be an amount not greater than the spacing between the lower end 31 of cap sleeve 30 and floating ring 14 when the parts are assembled as shown in FIG. 1 with the mandrel 9 telescoped within tapered shell section 1 but not penetration wedged.

' All'parts normally are assembled in telescoped relation as shown in FIG. 1 before driving blows are applied or wedging occurs. That is, an effort is made to select the required length of shell extension sections 4 and these are connected together and assembled as shown so that the mandrel does not have to be extracted during driving to insert an additional shell extension section. Furthermore, the showing of FIG. 1 is typical since variations in tapered flute formations, wear, etc. can slightly alter the relative positions shown. With such initial positioning, the predetermined indicated amount of penetration of tapered shell section 1 by the tapered mandrel portion 10 that subsequently can occur during initial driving may be measured as the axial distance of the spacing between the top face of floating ring 14 and the lower end surface 31 of cap sleeve 30.

With the parts in the position of FIG. 1, operation of hammer 8 drives mandrel 9 downward in shell 1 to penetrate the tapered shell section-the predetermined'or controlled amount or distance until the relative position of the parts shown in FIG. 2 is established. At this time cap wall 26 is in driving engagement with the upper end 12 of head portion 11 of mandrel 9, end surface 31 of sleeve 30 is in driving engagement with floating ring 14 which in turn engages upper end 35 of secondary mandrel sleeve 33, the lower end 34 of which engages connection ring shoulder 36 to establish direct driving engagement from cap 20 to the head or upper end 3 of tapered shell section 1, and the controlled predetermined penetration of shell 1 by mandrel portion is achieved.

Under these conditions frictional driving contact between flute valleys of shell section 1 and the engaged tapered surfaces of mandrel portion 10 has been established, and the force of hammer blows is transmitted by driving cap not only to the upper end 3 of shell 1 but also simultaneously to shell 1 through the frictionally engaged tapered surfaces of mandrel section 10 and shell 1.

As indicated, the tapered portion 10 of mandrel 9 may have the same taper as that of shell 1 or the mandrel taper may be slightly greater than that of the shell so that during controlled penetration of the shell by the mandrel frictional wedge contact therebetween is established progressively from the top of tapered mandrel section 10 to the lower end thereof.

Driving of shell 1 continues by operation of hammer 4 until shell section 1 has reached the desired driven position in the ground. At this time driving head 20 is raised free of driving engagement With the upper end of mandrel 9 to a position somewhat as illustrated in FIG. 3. Then an extractor convertor ring generally indicated at 39 in FIG. 3 is inserted between end surface .31 of cap sleeve and the top surface of floating driving ring 14 to maintain cap wall 26 spaced from the upper end 12 of mandrel head portion 11.

Ring 39 preferably is composed of similar half sections 40 and 41 hinged or bolted together as indicated at 42. Extractor convertor ring 39 thus is removable and insertable when desired. After extractor ring 39 has been inserted as shown in FIG. 3, an upward pull may be exerted on the ends of extractor bar 17 by cables 43 suspended from a winch on the driving equipment. Cables 43 may be connected to extractor bar 17 at all times to suspend the mandrel 9 from the driving equipment and the cables are only subjected to lifting force during mandrel extracting or lifting operations.

Hammer 8 is then operated to drive cap 20 against extractor ring 39 while an upward pull through cables 43 is exerted on mandrel 9. In this manner the frictional engagement between the tapered portion 10 of mandrel 9 and tapered shell section 1 is loosened or disengaged and mandrel 9 may be extracted or lifted from the driven shell leaving shell sections 1 and 4 in the ground to serve as a form in which concrete may be poured if desired to provide the final pile structure.

During extraction of mandrel 9, the supplementary mandrel sleeve 33 may be lashed by suitable means not shown to lift it from the driven shells either at the same time that mandrel 9 is extracted or after extraction of mandrel 9.

In accordance with the invention, particularly where exceedingly long piles are required, a standardized tapered shell section 1 may be driven into the ground through driving wedge engagement with a tapered mandrel portion telescoped therein and also simultaneously by top driving the tapered shell section, and the tapered shell section is used to pull any type of shell extension section into the ground, of any shape, thickness or diameter desired and normally not Itapered, and which may be made of considerably thinner tubular shell material than can withstand direct driving.

Thus, any job normally only will require one standard size of tapered driven pile section and a matching man drel to be supplied, regardless of the depth of penetration. Light gauge shell extension sections as required to meet depth conditions for any particular pile are pulled down by the driven standard tapered shell section.

This is all accomplished in accordance with the present invention by securing a shouldered ring at the top of a tapered shell section and by driving the tapered section with a main and a secondary mandrel.

Accordingly, the present invention provides an improved pile driving mandrel and shell construction and procedure which are simple and practical to use and relatively low in cost as compared with the prior driving of extensible piles; which solve problems that have existed in the art; which avoid difliculties previously encountered in the driving of extensible piles; which enable light gauge tapered sheet metal pile sections to be driven and extremely light gauge shell extension sections to be pulled into the ground; and which eliminate other difiiculties heretofore encountered in the art, achieve the stated objects, accomplish the many new functions and results described, and generally solve problems which have existed in the art.

In the foregoing description, certain terms have been used for brevity, clearness and understanding but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such terms are used for descriptive purposes and are intended to be broadly construed.

Thus, the terms rigid or substantially rigid used herein are intended to describe mandrels having sufficient rigidity and strength to be driven into the ground or removed therefrom Without failure under normal condition; and the terms ribbed, corrugated, or fluted are used herein more or less synonymously to refer to tapered structures with which spaced line contacts may be established in telescoped relation to and in engaged relation with other tapered members circular in cross section.

Moreover, the description .and illustration of the invention is by way of example and the scope of the invention is not limited to the exact structural details shown or to the lengths and metal thickness described for example, because the sizes of the various parts and components may be varied to provide other structural embodiments without departing from the fundamental principles of the invention.

Having now described the features, discoveries and.

ments, subcombinations, arrangements, relationships, con-- structions, methods, and steps and mechanical equivalents obvious to those skilled in the art are set forth in the appended claims.

I claim:

1. Apparatus for setting piles, including a tapered tubular sheet metal pile shell section having a nose and an upper end provided with an outer side, a thin gauge tubular sheet metal shell extension section having a lower end provided with an inner side, ring means connected to the tapered section upper end and to the extension section lower end with the extension section extending upwardly of the upper end of said tapered section, said ring means including a portion extending inwardly of the inner side of the extension section to the outer side of the upper end of the tapered section and forming a driving shoulder, a substantially rigid longitudinally continuous main mandrel member having a head portion with an upper end and a tapered shell contacting portion extending downwardly from the head portion and telescoped in contact within the tapered shell section, a secondary tubular mandrel member telescoped within said shell extension section and surrounding the main mandrel head portion having a lower end engaged with said driving shoulder and having an upper end located adjacent but spaced below the main mandrel upper end, mandrel-engaging and shelldriving cap means releasably telescoped over .and engaged with the main mandrel upper end, the tapered mandrel portion in cont-act with the tapered shell section prior to driving holding the cap means spaced from driving engagement with the upper end of said secondary mandrel member, and means for establishing driving engagement between the cap means and the upper end of the secondary mandrel member to directly drive the upper end of the tapered shell section through said secondary mandrel and driving shoulder after the mandrel has been driven into the tapered shell section to penetrate the tapered shell section a predetermined distance.

2. The apparatus defined in claim 1, in which the means for establishing driving engagement between the cap means and the upper end of the secondary mandrel member includes a floating driving ring movable axially of the main mandrel head portion and located between the cap means and the upper end of the secondary mandrel member.

3. The apparatus defined in claim 1, in which the tapered shell section is longitudinally fl'uted and the tapered mandrel portion is circular in cross section.

4-. The apparatus defined in claim 1, in which the shell extension section is corrugated and generally cylindrical in extent.

5. The apparatus defined in claim 1, in which the ring means comprises an annular shoulder portion, a downwardly extending sleeve portion connected with the upper end of the tapered shell section, and an upwardly extending sleeve portion surrounding the annular shoulder portion and connected with the lower end of the shell extension section.

6. The apparatus defined in claim 1, in which the tapered mandrel portion is shorter in length than the tapered shell section, and in which the cap means engaging the upper end of the mandrel establishes driving engagement with the upper end of the secondary mandrel member and through the latter with the ring means and the upper end of the tapered shell section before the lower end of the mandrel contacts the tapered shell section nose on penetration by the mandrel of the tapered shell section.

7. The method of driving extensible piles including the steps of telescoping a downwardly inwardly tapered portion of a substantially rigid longitudinally continuous mandrel having a head at one end and a nose at the other end into a light gauge tapered tubular sheet metal pile shell section having a shoulder at one end, a nose at the other end and a lighter gauge tubular sheet metal pile extension section extending upwardly from the shoulder; then driving the head of the mandrel to drive the mandrel relatively into the tapered shell section to penetrate the shell section a predetermined distance and frictionally wedge-engage tapered telescoped contacting surfaces of the mandrel and tapered shell sections thereby establishing frictional driving engagement therebetween; then simultaneously driving the mandrel head and the tapered shell section shoulder to drive the tapered shell section into the ground to the desired depth; pulling the shell extension section into the ground by the driving of the tapered shell section; then freeing the mandrel of driving engagement while maintaining driving engagement with the tapered shell section shoulder; and then driving the shell section shoulder while pulling on the mandrel to extract the mandrel from the driven shell sections.

References Cited UNITED STATES PATENTS 4/1935 Thornley 6153.7 4/1936 Orr et a1. 6 1--53.7

Claims (1)

1. APPARATUS FOR SETTING PILES, INCLUDING A TAPERED TUBULAR SHEET METAL PILE SHELL SECTION HAVING A NOSE AND AN UPPER END PROVIDED WITH AN OUTER SIDE, A THIN GAUGE TUBULAR SHEET METAL SHELL EXTENSION SECTION HAVING A LOWER END PROVIDED WITH AN INNER SIDE, RING MEANS CONNECTED TO THE TAPERED SECTION UPPER END AND TO THE EXTENSION SECTION LOWER END WITH THE EXTENSION SECTION, SAID RING MEANS OF THE UPPER END OF SAID TAPERED SECTION, SAID RING MEANS INCLUDING A PORTION EXTENDING INWARDLY OF THE INNER SIDE OF THE EXTENSION SECTION TO THE OUTER SIDE OF THE UPPER END OF THE TAPERED SECTION AND FORMING A DRIVING SHOULDER, A SUBSTANTIALLY RIGID LONGITUDINALLY CONTINUOUS MAIN MANDREL MEMBER HAVING A HEAD PORTION WITH AN UPPER END AND A TAPERED SHELL CONTACTING PORTION EXTENDING DOWNWARDLY FROM THE HEAD PORTION AND TELSESCOPED IN CONTACT WITHIN THE TAPERED SHELL SECTION, A SECONDARY TUBULAR MANDREL MEMBER TELESCOPED WITHIN SAID SHELL EXTENSION SECTION AND SURROUNDING THE MAIN MANDREL HEAD PORTION HAVING A LOWER END ENGAGED WITH SAID DRIVING SHOULDER AND HAVING AN UPPER END LOCATED ADJACENT BUT SPACED BELOW THE MAIN MANDREL UPPER END, MANDREL-ENGAGING AND SHELLDRIVING CAP MEANS RELEASABLY TELESCOPED OVER AND ENGAGED WITH THE MAIN MANDREL UPPER END, THE TAPERED MANDREL PORTION IN CONTACT WITH THE TAPERED SHELL SECTION PRIOR TO DRIVING HOLDING THE CAP MEANS SPACED FROM DRIVING ENGAGEMENT WITH THE UPPER END OF SAID SECONDARY MANDREL MEMBER, AND MEANS FOR ESTABLISHING DRIVING ENGAGEMENT BETWEEN THE CAP MEANS AND THE UPPER END OF THE SECONDARY MANDREL MEMBER TO DIRECTLY DRIVE THE UPPER END OF THE TAPERED SHELL SECTION THROUGH SAID SECONDARY MANDREL AND DRIVING SHOULDER AFTER THE MANDREL HAS BEEN DRIVEN INTO THE TAPERED SHELL SECTION TO PENETRATE THE TAPERED SHELL SECTION A PREDETERMINED DISTANCE.

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