This invention is a rigid metallic double sleeve type coupler for pipe, open-ended pipe pile, and pre-cast concrete pile which is installed with a high energy driving force such as that of a pile driving hammer. The expansion or contraction of the wall of the pipe pile incidental to installation of the coupler produces a metal-to-metal leakproof seal and a connection of high strength under tension between successive sections of pipe, pipe pile, and pre-cast concrete pile.
In the installation of pipe lines of large diameter pipe utilized for long distance transmission of gases and liquids, the sections of pipe are connected together by welding or by the use of sleeve type couplers having gaskets which make sealing contact with the exterior of the pipe. The welding of pipe of large diameter requires specialized welding equipment and trained personnel in order to insure a satisfactory, durable and leakproof joint. The welding operation is frequently difficult under field conditions due to the terrain through which the pipe line is being laid. Moreover, the welding operation is costly and time consuming. The gasket type couplers are not as durable or permanent as might be desired because of deterioration of the gaskets. Moreover, the gasket type couplers do not, so far as is known, provide satisfactory tensile strength.
Also, in pile driving operations utilizing hollow or pipe pile, it is often necessary to splice a second section of pipe pile to one already driven in the ground in order to reach a sound bering on bed rock. Such splicing is accomplished either by a welding operation or by the use of conventional drive sleeves. Welding of pipe pile in the field provides a satisfactory splice but is costly and time consuming because during the welding operation, some of the pile driving crew as well as the equipment are idle. The present known drive sleeves, such as that in prior U.S. Pat. No. 3,326,006, provide little or no tensile strength and they, therefore, cannot be used where tension or bending stresses are present in the piles. Thus in many cases, the known drive sleeves cannot be employed.
In my prior U.S. Pat. No. 3,762,173 issued Oct. 2, 1973, there is disclosed a drive sleeve for pipe pile which has certain advantages but which does not provide a leakproof or sealed connection. In my prior copending application Ser. No. 421,736 filed Dec. 4, 1973, there is disclosed a sleeve type coupler for pipe pile which provides a leakproof seal, thereby preventing seepage of water into a driven pile. Seepage of water into a driven pile is objectionable in that it causes rust to develop inside the pile and in that an accumulation of water inside the pile interferes with a satisfactory filling of the pile with aggregates or cement.
It is the purpose of my present invention to provide an improved type of sleeve coupler for pipe, open-end pipe pile, and pre-cast concrete pile which not only insures a leakproof seal but which also is capable of sustaining high tensile forces.
More particularly, I provide a number of various forms of coupler for pipe, open-end pipe pile, and pre-cast concrete pile, of the double or concentric sleeve type wherein the annular space between the two sleeves provides a socket which expands toward the center of the coupler from a smaller to a larger diameter cylindrical section. The expansion of the pipe or pipe pile over the inner sleeve to an expanded cylindrical portion as the pipe is driven home provides a metal-to-metal seal while separation of pipe, pipe pile or pre-cast pile from the coupler due to the tension therebetween is resisted by the reaction against the outer sleeve.
I further provide a number of different forms of double sleeve type of coupler as above described, in which the length of the inner expanded cylindrical portion of the annular socket substantially exceeds the thickness of the socket, thereby providing the means for resisting separation of pipe or pipe pile sections from the coupler under tension.
I further provide various forms of pipe pile, and pre-cast concrete pile embodying therein couplers of the double sleeve type.
I further provide a number of variations of double sleeve coupler of the type heretofore described wherein a central ring or wall is interposed between two longitudinally spaced annular sockets to serve as a drive ring whereby one pipe pile section may drive another.
I further provide a method and means for making and for installing the double sleeve type couplers previously described.
Further and more explicit details of the double sleeve type of coupler, as a separate unit or in combination with pipe pile and pre-cast concrete pile, as well as a method and means of making and of installation of the couplers will be described hereinafter in connection with the accompanying drawings, wherein:
FIG. 1 is a longitudinal cross-sectional view of one embodiment of double sleeve coupler for pipe or pipe pile, showing one pipe section as driven into the coupler and one pipe section prior to being driven into the coupler;
FIG. 2 is a vertical cross-sectional view of another embodiment of double sleeve coupler, shown in position for connecting two superposed sections of pipe pile, one of which is driven home and the other before entering the coupler;
FIG. 3 is a vertical cross-sectional view of a variation of the double sleeve coupler shown in FIG. 2;
FIG. 4 is an elevational view of a mobile ram or hammer device for applying high energy driving forces to install double sleeve couplers;
FIG. 5 is a fragmental sectional view of a variation of the form of coupler shown in FIG. 2,
FIGS. 6 to 9 are fragmental sectional views, respectively, of four other modified forms of couplers for coupling plain end pipe and pipe pile sections of different diameters. In FIG. 6, the sockets at both ends of the coupler cause expansion of the pipe or pipe pile diameter to a larger diameter. In FIGS. 7 to 9, the sockets at opposite ends of the coupler differ in that one socket causes circumferential expansion of the pipe or pipe pile driven thereinto whereas the other socket causes circumferential contraction of the pipe or pipe pile driven thereinto;
FIGS. 10 to 12 are fragmental sectional views, respectively, of three other modified forms of couplers for joining pipe or pipe pile sections of different diameters;
FIG. 13 is a vertical sectional view, showing pre-cast concrete pile sections with outer metal shell embodying a form of coupler similar to that of FIG. 6;
FIG. 14 is a vertical sectional view, showing pre-cast concrete pile sections (without outer shell) embodying a form of coupler similar to that of FIG. 6;
FIG. 15 is a vertical sectional view, showing a composite of pre-cast concrete pile with outer shell and an open-end pipe pile, the former embodying a coupler similar to that of FIG. 6;
FIG. 16 is a vertical sectional view, showing a composite of an open-end pipe pile and an upper section of mandrel driven thin-wall pipe pile of somewhat larger diameter closed at its lower end and embodying a coupler of the type shown in FIG. 6;
FIG. 17 is a vertical sectional view, showing a composite of pipe pile sections similar to that of FIG. 16 and embodying a coupler of the type shown in FIG. 6, the upper section of thin-wall pipe pile being open at its lower end; and
FIG. 18 is a fragmental vertical sectional view, showing a variation of the pipe pile sections of FIG. 17, in which the socket in the coupler embodied in the upper pile section causes circumferential contraction of the lower section of pipe pile as it is driven upwardly into the coupler as distinguished from circumferential expansion of the lower section of pipe pile characteristic of the coupler in FIG. 17.
Referring to the drawings, there is shown in FIG. 1 an embodiment of a pipe coupler 10 for coupling two coaxially juxtaposed sections of plain end pipe 11 and 11' of uniform diameter. Coupler 10 comprises an inner sleeve element 12 and an outer sleeve element 13, of rigid metallic nature, such as steel, arranged coaxially and concentrically. Inner sleeve element 12 is formed with a central annular projection 14 having a curved exterior outline and two shoulders 15 and 16 on opposite sides thereof. The outer sleeve element 13 is suitably formed, as by forging or pressing over the inner sleeve, in a manner that annular spaces 17 and 18 are formed at opposite ends of the coupling. The spaces 17 and 18 are of uniform thickness slightly larger than the thickness of the wall of the pipe 11 and 11' and flare outwardly toward projection 14 so as to terminate at the shoulders 15 and 16 respectively.
The inner and outer sleeve elements 12 and 13 are of a thickness and rigidity such that when the pipe sections are driven telescopically into the annular spaces 17 and 18 the end portion of the pipes is expanded, in correspondence with the outwardly flared inner end portion of the annular space. Due to the degree of expansion thus effected, the metal in the pipes is stretched beyond the elastic limit and also beyond the yield point of the metal. The shoulders 15 and 16 on the central projection serve to stop the inward movement of the pipe sections. In FIG. 1, the pipe section 11 is shown in the position and form it assumes when driven home in the annular space 17 into contact with the stop shoulder 15. Apparatus suitable for installing the coupler 10 on the pipe sections 11 and 11' is shown in FIG. 4 and will be described later.
In consequence of the expansion of the end of pipe section 11 over the inner sleeve element 12, a metal-to-metal seal is provided between the pipe section and the outer surface of the inner sleeve element 12. Conversely, in view of the flaring of the end of the pipe section 11 within the coupling, the outer sleeve element 13 restrains the separation of the pipe sections when placed under tensile stresses. Under service conditions, it is unlikely that the stresses tending to separate the pipe sections would equal or exceed the forces required to install the coupling, since in order to separate the pipe sections from the coupler a pull equal to the installation driving force would be required. Such a pulling force would far exceed that for which the pipe line is designed. Stated differently, on installation the metal pipe is stressed beyond the yield point of the metal but, under service conditions, the stresses on the metal pipe would be well below the yield point of the metal.
It will be observed that if the driving force on the pipe section is continued after the end of the pipe contacts either of the shoulders 15 or 16, such hammering force will tend to upset the end of the pipe and thus forge an even tighter and stronger connection with the coupler.
Coupler 10 is intended for a relatively permanent or a long-term type of installation and not for repeated or frequent installation and removal.
FIG. 2 illustrates a coupler 20 which is generally similar to coupler 10 but which is superior in certain aspects hereinafter described, which make for greater ease of manufacture and which adapts the coupler for more effective use in coupling pipe pile together.
As shown, coupler 20 comprises two substantially circular sleeve elements 21 and 22 of varying diameters disposed coaxially and concentrically one within the other and separated by a central ring 23. The sleeve elements 21 and 22 are made of metal, such as steel, and of a uniform thickness somewhat greater and stronger than that of the wall of pipe sections 24 and 24' to be coupled by the coupler, so that the sleeve elements are sufficiently rigid and strong to cause expansion of the end of the pipe sections into expanded cylindrical form when driven into the annular spaces 26 and 27 between the two sleeve elements and on opposite sides of the central ring 23, respectively.
The sleeve elements are similar in form but sufficiently different in diameter that the inner sleeve element 21 may be inserted telescopically within the outer sleeve element 22 with the central ring 23 installed in the outer sleeve element. As will be seen in FIG. 2, the sleeve elements are of uniform wall thickness but are of varying diameter, the outer cylindrical ends being smaller in diameter than the cylindrical central or mid-length area, and integrally joined thereto by a tapering or conical portion. Accordingly, the annular spaces 26 and 27 between the sleeve elements are of uniform thickness and slightly larger than the gauge thickness of the wall of the pipe sections 24 and 24'. As shown, the wall thickness of the sleeve elements corresponds closely to the spacing therebetween.
The central ring 23 is of uniform thickness corresponding to the thickness of the annular spaces 26 and 27 and is bonded, as by welding, to the sleeve elements 21 and 22. The degree of taper between the large and smaller diameter portions of the outer sleeve element 22 is such that the central ring 23 is first inserted through the end opening of the outer sleeve element 22 and then expanded to fit within the central large diameter portion of the outer sleeve element 22 and welded thereto. Subsequently, the outer sleeve element and ring 23 are slipped over the inner sleeve element 21 and then bonded together. Thus, the coupler 20 is more simply and readily assembled than the coupler 10.
It will be observed that the width of ring 23 is less than the length of the central larger diameter portion of the sleeve elements 21 and 22. Thus, the annular spaces 26 and 27 constitute sockets comprising an outer end portion of one diameter, an inner end portion larger in diameter than the outer end portion by an amount at least twice the spacing between the sleeves, and an intervening tapered portion connecting the two. The inner and outer cylindrical end portions of the spaces 26 and 27 are coaxial to each other and to the axis of the coupler 20 itself. The inner cylindrical end portions of spaces 26 and 27 are greater in length than the radial distance between the sleeves for a reason later made clear.
The advantage of this specific structure is that as the end of the pipe pile is driven into the annular spaces 26 and 27, the end of the pipe pile is first expanded outwardly by an amount approximately twice the spacing between the sleeve elements or in other words, the wall thickness of the pipe and pipe pile to a larger diameter and then maintained at the uniform larger diameter for a substantial length. Thus the impact forces on one pipe pile section, such as pipe pile section 24', are transmitted coaxially in a direct line from the expanded cylindrical end thereof to the central ring 23 and thence to the other pipe pile section 24. As shown in FIG. 2, the coupler 20 has been installed over the upright end of pipe pile section 24, which has already been driven into the ground at 28 and is awaiting entrance of the superposed pipe pile section 24' into the upper end of coupler 20. Coupler 20 is thus more suited to coupling pipe pile than is coupler 10, in which a portion of the driving forces exerted on one pipe section is diverted laterally and not fully and directly transmitted coaxially through the coupler to the other pipe section. Obviously, coupler 20 is also equally well adapted for use in coupling horizontally disposed pipe sections, as distinct from vertically disposed pipe pile. As a matter of fact, I have found that the form of coupler shown in FIG. 2, by reason of it causing the end of the pipe or pipe pile to be expanded by an amount equal to at least twice the amount of the spacing between the sleeves into a cylindrical form of larger diameter after expansion thereto, produces a joint which is tighter and stronger under tension forces than when simply flared at the end as in FIG. 1.
FIG. 3 shows a coupler 30 which is a variation of the coupler 20. As shown, coupler 30 differs from coupler 20 in that the outer and inner sleeve elements are made in two shorter longitudinally spaced parts 31, 31' and 32, 32' respectively, the inner ends of the sleeve parts being bonded, as by welding to a central ring 23'. The outer sleeve parts 31 and 31' are identical in configuration and are simply reversely but coaxially disposed in longitudinally spaced relation. Similarly, the inner sleeve parts 32 and 32' are identical in configuration and reversely and coaxially disposed in longitudinally spaced relation.
As is evident in FIG. 3, the sleeve parts are individually formed such that the end portions are of uniform diameter with one being of larger diameter than the other, and the two end portions being integrally joined by an intervening tapered portion.
In the matter of fabrication and assembly, coupler 30 has advantages over both couplers 10 and 20. Thus, it is not necessary to expand ring 23', as is the case with ring 23 of coupler 20, for the ring 23' is made to appropriate size orginally. Moreover, sleeve parts 31 and 32 may be bonded at one end to one side of the ring 23' and then the sleeve parts 31' and 32' may be bonded to the opposite side of the ring. As shown in FIG. 3, coupler 30 is installed on the end of a pipe pile section 34 already driven into the ground at 28', and a superposed pipe pile section 34' is poised above the coupler prior to being driven into the coupler.
Referring to FIG. 4, there is illustratively shown a mobile ram or hammer device 40 for installation of any of the forms of couplers 10, 20 and 30, coupler 10 being shown merely as an example.
Device 40 comprises a mobile platform 41 supported on two pairs of axle-connected wheels 42 and an auxiliary support ring 43 having a pair of axle-connected wheels 44. The auxiliary support ring 43 is attached to the platform 41 by a plurality of tension rods 45 circumferentially arranged and removably and adjustably secured to the ring 43 and to the annular flange 46 of a cylindrical cradle 47 attached to the platform 41.
At the end of the cylindrical cradle 47 opposite flange 46 is an open-ended cylinder 48 in which a piston-like ram 49 slidably operates. Also mounted on the platform 41 is a double-acting air cylinder 50, the piston 51 of which is connected to the ram 49 by a rod 52. Ports 53 and 54 are provided by which to admit and exhaust air under pressure from opposite sides of the piston 51.
The cradle 47 carries a plurality of angularly and adjustably spaced rollers 55 by which to support one end of a pipe section 56 coaxially within the cradle 47. In order to prevent upsetting the end of the pipe 56 due to blows of the ram 49 thereon, an intervening impact head 57 having an annular groove 58 in one face is provided, in which the end of pipe 56 is inserted.
The auxiliary support ring 43 carries a plurality of circularly arranged clamps or jaws 59 to grip a second section of pipe 56' on the end of which the coupler, such as coupler 10, has been placed.
In operation, the outer end of the pipe section 56 is inserted into the open end of the coupler 10, following which the tension rods 45 are suitably adjusted in length and tightened in position by nuts so as to hold the pipe sections and coupler in assembled relation. Having first made sure that the impact head 57 is secured properly in place over the inner end of the pipe section 56, the ram 49 may now be operated reciprocatively to deliver hammer blows to the impact head 57. The impact of the blows of the ram 49 on the head 57 drives the pipe sections into the annular spaces at opposite ends of the coupler until driven fully home.
It will be understood that ram 49 is reciprocated by the air pressure operated cylinder 50, operation of which is controlled by valves (not shown) in conduits connected respectively to the ports 53 and 54.
Referring to FIGS. 5 to 12, variants of the form of coupler shown in FIGS. 2 and 3 will now be described.
In FIG. 5, the form of coupler 60 shown comprises an inner circular sleeve 61 and an outer circular sleeve 62. The inner sleeve 61 has a smooth bore 63 of uniform diameter and an outer surface formed or machined with end sections 64 and 64' of the same diameters, a central section 65 of larger diameter than the end sections, and conical or tapered sections 66 and 66' intervening between and joining the end sections 64 and 64' to the central section 65. The outer surface of outer sleeve 62 is of uniform diameter, whereas the inner surface or bore thereof has sections of different diameter conformable to and paralleling the outer surface of the inner sleeve 61, the spacing between the two sleeves being uniform along the length of the sleeves. The sleeves are held in spaced relation by a central projection 66, extending inwardly from the central section of the outer sleeve. It will be seen that the bore 67 in the projection 66 conforms closely to the diameter of the central section 65 of the outer surface of the inner sleeve and seats firmly thereon. The two sleeves may be suitably bonded together as by spot welding via the projection 66 or by a plurality of machine screws (not shown) engaging registering topped holes in the two sleeves.
It will be seen that the annular spaces between the two sleeves 61 and 62 of coupler 60 provide sockets into which pipe or pipe pile may be driven. As in the coupler 20 of FIG. 2, the pipe or pipe pile driven into the sockets of coupler 60, are caused to expand over the conical or tapering sections 66 and 66' of sleeve 61 and then straighten out again into cylindrical form of uniform diameter as the end of the pipe or pipe pile enters the inner end section of the sockets. As with coupler 20, coupler 60 joins the pipe or pipe pile to the coupler so as to provide tremendous strength under tension by reason of the length of the inner end section of the annular socket.
Referring to FIGS. 6-9, the various forms of coupler respectively shown therein are designated generally by the reference numerals 71, 72, 73 and 74. These couplers are similar in that they all comprise a central collar 75, to one side of which is coaxially secured, as by welding, a first pair of concentric radially spaced sleeves, and to the other side of which is coaxially secured, as by welding, a second pair of concentric radially spaced sleeves. The one set of concentric sleeves of coupler 71 is identified by reference numerals 76 and 77 and the other set of concentric sleeves is identified by the reference numerals 78 and 79. Without detailed description, the annular space between the sleeves 76 and 77 of FIG. 6 will be referred to as socket 80 and the annular space between the sleeves 78 and 79 will be referred to as socket 81. It will be seen that both sockets 80 and 81 are of such configuration as to expand the pipe or pipe pile driven thereinto to a larger diameter as with previously described forms of couplers. It will be apparent that sockets 80 and 81 will accommodate pipe or pipe pile of different diameters, thus effecting a coupling of pipe or pipe pile of different diameters.
The several sets of concentric sleeves in couplers 72, 73 and 74 will be identified by reference numerals corresponding to those in FIG. 6, except with the suffix a, b, and c, respectively. The annular sockets in the couplers of FIGS. 7, 8 and 9 will similarly be identified by the same reference numeral as in FIG. 6 except with the suffix a, b and c.
It will be noted that the configuration of the upper and lower sets of concentric sleeves are not identical so that variations in the configuration of the annular sockets occur. It will be noted that sockets, 80a, 80b and 80c are different from socket 80 in that the inner end of these sockets is of smaller diameter than the outer end of the socket, whereas the inner end of socket 80 is of larger diameter than the outer end. Thus, it will be understood that as the pipe or pipe pile is driven into sockets 80a, 80b and 80c the pipe or pipe pile is circumferentially contracted as distinguished from the circumferential expansion, caused by socket 80.
It will be noted also that socket 80a is similar to socket 80 in that it terminates short of the collar 75, whereas sockets 80b and 80c extend fully to the collar 75.
The lower sets of sleeves for couplers 71 and 72 are identical, the inner end of sockets 81 and 81a both terminating short of the collar. The lower sets of sleeves for couplers 73 and 74 are identical but differ from those of couplers 71 and 72 in that the sockets 81b and 81c terminate at the collar 75. In all sockets 81, 81a, 81b and 81c the pipe or pipe pile is caused to expand as it is driven into the socket.
Referring to FIG. 10, another form of coupler 90 is shown, in which two sets of concentrically disposed sleeves are secured in coaxial relation as by welding. The upper set of concentric sleeves 91 and 92 form a socket 93 therebetween similar in configuration to socket 80a of coupler 72. The lower set of concentric sleeves 94 and 95 form a socket 96 therebetween which is similar in configuration to that of socket 81b of coupler 73. It will be seen that the inner extremities of sockets 93 and 96 are of the same diameter and in coaxial alignment. Thus the force driving a pipe pile into the upper set of sleeves of coupler 90 is transmitted to the shoulder 97 on the inner sleeve 92 and directly in an axial line to the pipe pile in socket 96.
Referring to FIG. 11, a coupler 100 is shown which is functionally and structurally similar to coupler 90 except that it consists of two concentrically disposed sleeves 101 and 102. The inner sleeve 101 has a central bore 103 which may be of uniform diameter or stepped as shown. The outer surface of sleeve 101 is formed, as by machining to provide the inner wall of two sockets 104 and 105 similar to sockets 93 and 96 of coupler 90. At the center of the outer surface of sleeve 101 is a projection 106 which serves to hold the two sleeves 101 and 102 in radially spaced relation. The two sleeves may be bonded, as by spot welding through the projection 106 or by screws engaging topped aligned holes including holes in the projection 106. The outer sleeve may have a smooth outer surface of uniform diameter or a stepped contour as shown. The inner bore of the outer sleeve 102 has a configuration conformable to that of the outer surface of the inner sleeve 101 thereby providing the outer wall of the two sockets 104 and 105.
Referring to FIG. 12, another form of coupler 110 is shown consisting of two concentric sleeves 111 and 112 of different diameters and held in uniformly radially spaced relation by a flat annular member or ring 113 interposed centrally therebetween. It will be noted that the contour of the outer surface 114 of the inner sleeve 111 and the contour of the bore 115 of the outer sleeve are parallel so as to form sockets 116 and 117 therebetween similar in appearance to sockets 104 and 105 of coupler 100. The sleeves 111 and 112 and the ring 113 are suitably secured together after assembly, as by spot welding or by screws engaging tapped aligned holes therein.
It will be observed that in both couplers 100 and 110, the sleeves can be assembled only by telescoping the larger diameter end of the outer sleeve over the smaller diameter end of the inner sleeve.
Referring to FIGS. 13 to 18, various forms of pipe pile sections, pre-cast concrete pile sections and composite pipe pile and cast concrete sections are shown in which various ways are depicted of embodying couplers of the type hereinbefore described.
In FIG. 13, there are shown a lower precast sectional pile secton 120 consisting of an outer thin wall pipe shell 121, a circular boot plate 122 secured, as by welding, to the lower end of the shell 121 within the bore, and a circular disc and pipe member 123 secured, as by welding to the upper end of the shell 121 within the bore thereof. Concrete 124 is deposited in the shell and allowed to set and harden before the member 123 is attached.
Also shown in FIG. 13, is an upper precast sectional pile section 125 comprising an outer thin-wall pipe shell 126, having secured in the bore thereof at its lower end a coupler socket unit 127. Socket unit 127 is similar to that of FIG. 6, comprising a collar 128 and two concentric sleeves 129 and 130 secured coaxially to one side of collar 128, and forming an annular socket 131 therebetween. The central bore 132 of the inner sleeve 130 is closed at its lower end by a snugly fit circular plate or disc 133, secured as by welding to the sleeve 130. The pipe shell 125 is filled with concrete 134 and after the concrete has hardened, a disc and pipe member 135 is secured as by welding in the top end of the bore of the shell.
In use, the lower pile section 120 is first driven into the ground to a depth leaving the disc and pipe member 123 exposed above ground level. The upper pile section 125 is then superposed in vertical alignment with the lower pile section so that it may be coupled to the lower section by insertion of the pipe section of member 123 into the socket 131, after which the upper pile section 125 may be driven downwardly as by a mandrel into coupled relation with the lower pile section. Once the pile sections are coupled as described, further pounding with the mandrel will drive both upper and lower pile sections concurrently into the ground. After the pile section 125 is driven sufficiently into the ground a third pile section, corresponding to pile section 125 may be similarly coupled to the top end of the pile section 125 and all pile sections driven further into the ground.
FIG. 14 shows a set of pile sections of pre-cast concrete, consisting of a lower pile section 140 and an upper pile section 141, similar to those of FIG. 13 except they are cast in molds and do not have the thin-wall pipe shells 121 and 126. For convenience, the parts of the pile sections in FIG. 14 corresponding to those of the pile sections of FIG. 13 are designated by the same reference numerals with the prime (') suffix without further description. In addition, the boot plate 122' and disc and pipe member 123' of the lower pile section 140 may be joined by reinforcing rods or dowels 142 welded thereto and reinforcing the concrete poured around them in a mold. Similarly, the collar 128' of socket unit 127' may be joined to disc and pipe member 135' through reinforcing rods or dowels 143 welded thereto and around which concrete is poured while in a mold.
FIG. 15 shows a set of pile sections, the lower one of which is an open-ended pipe pile section 145, and the upper one of which 146 is a composite pre-cast type of pile section similar to pile section 125 of FIG. 13.
In view of the prior full description of the pile section 125 of FIG. 13, no further description of pile section 146 is deemed necessary.
It will be apparent that the upper pile section 146 is coupled to the pipe pile section 145 by aligning the annular socket of the socket unit with the upper end of the pipe pile 145 and then driving the upper pile section downwardly.
FIG. 16 shows a set of pile sections, the lower one 147 of which is an open-ended pipe pile and the upper one 149 of which is a thin-walled pipe pile section as distinguished from the pile section 146 of FIG. 15. Pile section 149 has a circular disc 150 secured, as by spot welding, within the bore of the pile section 149, to which the socket unit 151 has been previously attached. In this case the central bore of the inner sleeve of the socket unit 151 is open at the bottom, no closure disc, such as the disc 133 of FIG. 13, being necessary.
In use, the upper pile section 149 may be coupled to the pipe pile section 147 and then further driving of both upper and lower pile sections accomplished by means of a mandrel 152 of conventional pile driving equipment. After the upper pile section 149 is driven fully into the ground as desired, the mandrel 152 is removed and the upper pile section then filled with concrete.
FIG. 17 shows a set of pipe pile sections 147' and 149' similar to pile sections 147 and 149 of FIG. 16. In this case, however, socket unit 127", similar to socket unit 127 of FIG. 13, is employed, wherein a pair of concentric sleeves are secured coaxially to one side of a collar 128". Also the bore of the internal sleeve of the socket unit is left open and a disc similar to disc 133 of FIG. 13 is omitted. In this case, a pipe pile section 153 may be employed to drive the upper pile section, instead of the mandrel 152 being so used. Upon completion of the pile driving operation, the both pile sections 147' and 149' may be filled with aggregate or concrete via the upper pile section 149', since the interiors of the pile sections are open to each other through the internal bore of the socket unit 127".
FIG. 18 is a fragmental sectional view, showing a variation of the upper pipe pile section of FIG. 17, which enables a smaller diameter pile section to be employed. In FIG. 18, the shell of a pipe pile 155 smaller in diameter than that of pipe pile 149' of FIG. 17, is employed. A socket unit 156, of correspondingly smaller diameter to socket unit 127", is secured within the shell of the pipe pile 155. Moreover, socket unit 156 contains an annular socket 157 differing from that of socket unit 127" in that it causes circumferential contraction of the pipe pile as it is driven into the socket unit 156.
It will be seen that in this particular embodiment of coupler and pipe pile, it is thus possible to employ an upper pile section more closely conforming to the diameter of the lower pile section than is the case in the combination of pile sections shown in FIG. 17.