AU2013245456B2 - Plug connector for piles - Google Patents

Abstract

A plug connector for piles has a body with at least a lower body portion received in, and secured to, an upper end of the shaft of the pile. A screw 5 threaded bore in, or through, the body receives an anchor bolt to secure a load to the pile, being capable of resisting lateral or uplifting forces. At least one flange (or recess) is provided on an upper body portion for engagement with a complementary formation in a driving head used to drive the pile into the ground.

Description

2013245456 14 Oct 2013

AUSTRALIA

Patents Act 1990 P/00/011 Regulation 3.2

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT

Invention Title: "PLUG CONNECTOR FOR PILES"

The following statement is a full description of this invention, including the best method of performing it known to me/us: 1 2013245456 14 Oct 2013 TITLE: PLUG CONNECTOR FOR PILES BACKGROUND OF THE INVENTION: 1. Field of the Invention : [0001] This invention relates to a plug connector for piles.

[0002] The invention particularly relates, but is not limited to, a plug connector mountable in the shaft of a screw- or blade-pile for connection to a load supported thereby; and to piles fitted with the plug connectors. 2. Prior Art: [0003] Piles, having (typically hollow) steel shafts, are used to support building constructions, more typically building slabs, and are screw-driven into the soils below the slabs to be constructed.

[0004] Screw piles have at least one helical screw- or flyte around the shafts, usually adjacent the digging point at the lower end of the shafts. The helical screws- orflytes may be provided at spaced locations along the shafts, to spread the load transfer from the piles to the surrounding soil.

[0005] The present inventor developed a variation on such screw piles, where the helical screws were replaced by inclined blades extending from the shanks, the blades typically being provided in diametrically-opposed pairs.

[0006] For a given load capacity, the blade piles could be more easily driven into the soils, due to the reduced torque required to drive the blades into the soils.

[0007] Hereinafter, throughout the specification, the term “piles” will be used to include both screw piles and blade piles and like piles or piers.

[0008] Many geographical areas in Australia, including Adelaide, have reactive soils, typically containing a high clay content. It is not unknown for such reactive soils to be liable to vertical “heave” exceeding 30cm between fully dry and fully wet.

[0009] The ‘heave” of the reactive soils has resulted in damage to building foundations, and to vertical displacement of a building relative to adjacent facilities / utilities.

[0010] One solution used to try to overcome the effects of the “heave” has been the 2013245456 14 Oct 2013 2 use of building slabs, supported on piers or piles anchored in underlying stable soil zones e.g. bedrock.

[0011] It has been known, however, that the “heave” of the reactive soils e.g. following rain after a long period of drought, has been so large as to raise the slabs from the supporting piers or piles. Furthermore, as the soils have dried, the slabs have re-engaged the piers or piles, but horizontally offset from their original positions.

[0012] International Publication WO 2010/096883 A1 (= PCT/AU2010/000233 = AU 2010217205) (Trista Technology Pty Ltd) discloses a ’’Building Construction Method and System” where the perimeter beams of the building slab have sloped lower surface(s) to divert the swelling (i.e. reactive) soils away from the perimeter beams e.g. into voids. The slab is supported by a plurality of screw piles. The perimeter beams are tied to supports or cradles, positioned on the screw piles. Each screw pile is fitted with a pile cap such that a structural slip joint is formed between the pile cap and the slab.

[0013] This means that the slab can still move vertically as the soils swells. While the vertical movement of the slab is relatively controlled, such movement can lead to the failure of utilities (e.g. water pipes, sewage pipes, storm-water pipes, electricity cables and telephone wires 0 fibre cables) connected to the slab or the building supported thereon. OBJECTS OF THE PRESENT INVENTION: [0014] It is an object of the present invention to overcome, or at least ameliorate, one or more problems with the prior art.

[0015} It is a preferred object to provide a plug connector mountable in the shafts of the piles, which can resist upwardly directed forces, while supporting a load on the piles.

[0016] It is a further preferred object to provide a plug connector releasably engageable by a driving head on an excavator or like for screw-driving the pile into the ground.

[0017] Other preferred objects of the present invention will become apparent from the following description. 3 2013245456 14 Oct 2013 SUMMARY OF THE PRESENT INVENTION: [0018] In one aspect, the present invention resides in a plug connector for a pile including: a body dimensioned to be received in an end of a shaft of a pile; and a screw-threaded bore open to at least an upper end of the body, co-axial therewith, to operably connect the shaft to a load supportable by the pile; wherein at least one flange and/or recess is provided on the body, for releasable engagement with a complementary formation in and/or on a driving head operable to rotate the shaft.

[0019] In one preferred embodiment, a lower portion of the body is welded to an adjacent portion of the shaft; and the bore extends through the body.

[0020} In another preferred embodiment, a lower portion of the body is secured to the shaft by at least one transverse fastener extending through a transverse passage in the lower portion of the body and at least one wall portion of an upper end of the shaft; and the bore is terminated spaced from the transverse passage.

[0021] Preferably, the flange(s) and/or recess(es) may be regularly or irregularly arranged; and may be only engageable by a complementary “key” (of either male- or female configuration) on the driving tool.

[0021 A] More preferably, the upper portion of the body has four radially extending flanges, which form a cruciform-like formation, releasably engageable with the complementary formation of the driving head.

[0022] In a second aspect, the present invention resides in a pile including: a substantially-tubular shaft; at least one helical-screw or blade at or adjacent a digging formation at a lower end of the shaft; and a plug connector, as hereinbefore described, received in, and secured to, an upper end of the shaft. BRIEF DESCRIPTION OF THE DRAWINGS: [0023] To enable the skilled workman to fully understand the invention, and to enable that person to put the invention into practice, preferred embodiments will now be 4 2013245456 14 Oct 2013 described with reference to the accompanying drawings, in which: FIG. 1 is a schematic sectional side view of a plug connector, in accordance with a first embodiment, mounted in the shaft of a screw pile; FIG. 2 is a top plan view of the plug connector; and FIG. 3 is a schematic sectional side view of a plug connector, in accordance with a second embodiment, mounted in the shaft of a screw pile.

[0024] NB: Any annotations, dimensions, or the like on FIGS. 1 to 3 are by way of illustration only, and are not limiting to the scope of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS: [0025] The preferred embodiments, described with reference to FIGS. 1 and 2, or FIG. 3, provide plug connectors 10,110 for conventional screw piles P with a tubular shaft 40, where screw- or blade-blade formation(s) (not shown) are provided at the lower end of the shaft 40 adjacent and/or spaced above a digging point (also not shown). The shaft 40 may have an external diameter = 76mm and a wall thickness = 4mm.

[0026] The plug connector 10 illustrated in FIGS. 1 and 2 has a body 20 with a substantially-cylindrical lower portion 21 dimensioned for firm engagement within the upper end 41 of the shaft 40.

[0027] An upper portion 22 of the body 20 has four radially-extending flanges 23, which form a cruciform-like formation 24, as illustrated in FIG. 2, to be releasably engaged by a complementary formation of a driving head (not shown) mounted on an excavator (also not shown) operable to rotate the shaft 40 to drive the screw pile P into the ground.

[0028] The under-side faces 25 of each of the flanges 23 engage the annular face 42 at the upper end 41 of the shaft 40.

[0029] The body 20 is welded to the upper end 41 of the shaft 40, including welding beads (not shown) interconnecting the body 20 to the annular face 42 intermediate the flanges 23.

[0030] A screw-threaded bore 26 extends co-axially through the body 20, for engagement by an anchor bolt or other fastener (not shown) which is operable to secure a load to be supported by the pile P. The anchor bolt not only secures the 5 2013245456 14 Oct 2013 load against lateral movement relative to the pile P, but will also resist any uplifting forces applied to the load e.g. due to “heave” of the underlying soil.

[0031] The plug connector 10 is preferably cast or machined from a single piece of metal, e.g. steel, iron or aluminium. When the plug connector 10 is formed by casting, the screw-threaded bore 26 will preferably be machined to its final profile.

[0032] In the embodiment illustrated in FIGS. 1 and 2, the lower- and upper portions 21,22 of the body 20 are of equal length, but this may be varied dependent on the intended installation for the pile P.

[0033] The second embodiment of the plug connector 110, illustrated in FIG. 3, is suitable for use where the shaft 140 of the pile P has to be cut to the correct height e.g. when the digging point and screw- or blade-formation(s) have engaged rock or stiff clay which prevents the pile P being driven further into the ground.

[0034] The plug connector 110 has a body 120 generally similar to the body 20, with the radially-extending flanges 123 for engagement with a driving head as hereinbefore described.

[0035] A transverse passage 127 extends diagonally through the lower portion 121 of the body 120; and the screw-threaded bore 126 is terminated by an inner end wall 128 spaced above the transverse passage 127. The skilled addressee will note that in the plug connector 110, the length of the lower portion 121 of the body 120 is preferably at least twice the length of the upper portion 122; and that the length of the bore 126 is preferably equal to the length of the bore 26 to enable effective engagement between an anchor bolt and bores 26, 126.

[0036] To install the plug connector 110 in the shaft 140, the shaft 140 is cut to length to provide an annular face 142 at the upper end 141.

[0037] A pair of diametrically-opposed holes 143 are drilled or cut through the upper end 141 of the shaft 140 for co-axial alignment with the transverse passage 127 through the body 120.

[0038] The lower portion 121 of the body 120 is inserted into the upper end 141 of the shaft 140 until the flanges 123 engage the annular face 142. The body 120 may be rotated relative to the shaft 140 to bring the transverse passage 127 into alignment with the holes 143.

[0039] A locking bolt 144 is passed through the aligned transverse passage 127 and 6 2013245456 14 Oct 2013 holes 143 and is secured by a locking nut 145. The locking bolt 144 prevents release of the plug connector 110 from the shaft 140 against uplifting forces, and also assists in transferring rotary drive from the driving head, through the plug connector 110, to the shaft 140.

[0040] The skilled addressee will appreciate that one or more of the flanges 23,123 may be substituted by recesses; and that the number of flanges and/or recesses may be one or more, where multiple flanges and/or recesses may be evenly, or unevenly, spaced about the body 20, 120 e.g. so that a manufacturer can produce the plug connectors 10,110 so that they will only be engageable by a driving head, or “key”, manufactured, or supplied, by that manufacturer or under their authority. The flanges and/or recesses, which are engageable by the “key” on the driving tool, may be of an irregular shape; and the “key” may have either a male configuration (e.g. in the nature of a screw-driver) or a female configuration (in the nature of a socket).

[0041 ] While the illustrated embodiments show the flanges extending from the upper portion of the body, the skilled addressee will appreciate that e.g. the recesses may extend down to the lower portion of the body, so that the key may be received between the body and the upper end of the shaft of the pile.

[0042] The skilled addressee will appreciate that the plug connectors hereinbefore described and illustrated have a number of advantages: a) The plug connectors are easily secured in the shafts of the piles; b) The plug connectors provide a simple / secure means for securing load(s) to pile(s); c) The plug connectors provide a means for connecting the load(s) to the pile(s) which can resist uplifting forces; d) The plug connectors provide a releasable coupling between a driving head and the shafts of the piles to enable the latter to be driven into the ground; and e) The provision of the flanges and/or recesses on the plug connector can be configured to ensure the piles can only be driven by authorised driving tools supplied by, or with the authority of the manufacturer, for improved quality control.

[0043] The plug connectors can be used with existing piles with nil, or minimal, modification required to the shafts of the piles P.

[0044] the skilled addressee will appreciate that the present invention also provides a 2013245456 14 Oct 2013 7 method of driving a pile into soil, the pile being of the type having a substantially -tubular shaft with at least one helical-screw or blade at or adjacent a digging formation at a lower end of the shaft; the method including the steps of: a) securing a plug connector as hereinbefore described in an upper end of the shaft; b) engaging the digging formation with the soil; c) engaging a driving head, complementary to the plug connector and mounted on a rotary pile driving machine, with the plug connector; and d) operating the rotary pile driving machine to transmit a rotating, downwardly-directed, driving force on the pile to drive the pile into the soil.

[0045] Various changes and modifications may be made to the embodiments described and illustrated without departing from the present invention.

Claims (6)

1. CLAIMS:

   1. A plug connector for piles including: a body dimensioned to be received in an end of a shaft of a pile; and a screw-threaded bore open to at least an upper end of the body, co-axial therewith, to operably connect the shaft to a load supportable by the pile; wherein at least one flange and/or recess is provided on at least an upper portion of the body, for releasable engagement with a complementary formation in and/or on a driving head operable to rotate the shaft.
2. 2. The plug connector of claim 1, wherein: a lower portion of the body is welded to an adjacent portion of the shaft; and the bore extends through the body.
3. 3. The plug connector of claim 1, wherein: a lower portion of the body is secured to the shaft by at least one transverse fastener extending through a transverse passage in the lower portion of the body and at least one wall portion of the shaft; and the bore is terminated spaced from the transverse passage.
4. 4. The plug connector of any one of claims 1 to 3, wherein: the upper portion of the body has four radially extending flanges, which form a cruciform-like formation, releasably engageable with the complementary formation of the driving head.
5. 5. A pile including: a substantially-tubular shaft; at least one helical-screw or blade at or adjacent a digging formation at a lower end of the shaft; and a plug connector as claimed in any one of claims 1 to 4, received in, and secured to, an upper end of the shaft.
6. 6. A method of driving a pile into soil, the pile being of the type having a substantially -tubular shaft with at least one helical-screw or blade at or adjacent a digging formation at a lower end of the shaft; the method including the steps of: a) securing a plug connector as claimed in any one of claims 1 to 4 in an upper end of the shaft; b) engaging the digging formation with the soil; c) engaging a driving head, complementary to the plug connector and mounted on a rotary pile driving machine, with the plug connector; and d) operating the rotary pile driving machine to transmit a rotating, downwardly-directed, driving force on the pile to drive the pile into the soil.