AU2013100624A4 - Extensions for piles - Google Patents

Abstract

An extension for a screw-pile or blade-pile has a tubular shaft with a driving head at one end, the driving head having a bore with a screw 5 thread or other formation. A connecting head at the other end of the shaft has a shank engageable with the bore of a driving head on the screw-pile or blade-pile, or on a similar extension, to enable one or more extensions to be operably connected to the screw-pile or blade pile to enable the pile to be driven to a greater depth. All a d ------- ---------

Description

P/00/012 Regulation 3.2 AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION INNOVATION PATENT Invention Title: "EXTENSIONS FOR PILES" The following statement is a full description of this invention, including the best method of performing it known to me/us: 1 TITLE: EXTENSION FOR PILES BACKGROUND OF THE INVENTION: 1.. Field of the Invention: 5 [0001] This invention relates to an extension for piles. [0002] [0002] The invention particularly relates, but is not limited to, improved extensions for screw piles and blade piles. [0003] NB: Throughout the specification, the term "piles" will be used to include both "piles" and "piers". 10 2. Prior art: [0004] NB: The following discussion is by way of background information only, and is not to be considered a statement of the common general knowledge (CGK) in the area of technology. [0005] Piles (or piers), having (typically hollow) steel shafts, are used to 15 support building constructions, more typically building slabs, and are rotatably-driven into the soils below the slabs to be constructed. [0006] Screw piles have at least one helical screw- or flyte around the shafts, usually adjacent the digging points at the lower end of the shafts. The helical screws- or flytes may be provided at spaced locations along 20 the shafts, to spread the load transfer from the piles to the surrounding soil. [0007] 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 25 pairs. [0008] 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. [0009] In areas within Australia, clay-based soils are subject to 30 considerable "heave" (or expansion) when they become wet. [0010] In areas with low-strength soils, such as flood-plains and coastal areas, bedrock or other higher-strength underlying soils may be many 2 metres (e.g. 15+ metres) below the soil surface. [0011] For effective support of building structures, including floor slabs, in the above areas, the piles may require shafts of 18+ metres length to fully support the slabs. For example, in areas with reactive soils, the pile 5 screw(s) or pile blades should be driven to a depth so that they are engaged in the underlying soils; while the building structures (e.g. slabs) must be supported at, or above, the highest expansion level of the soil when fully wetted (to avoid / minimise any uplifting forces on the slabs). In the other areas with low-strength soils, the screw(s) or pile blades should 10 also be driven into the higher-strength underlying soils to achieve the design loads for the piles. [0012] Piles are usually manufactured to modular shaft lengths, for given shaft diameters / screw or blade dimensions / design loads. To reduce production costs, it is not economic to produce / stock shafts in a range of 15 lengths e.g. increasing by 1 metre in length. OBJECTS OF THE INVENTION: [0013] It is an object of the present invention to provide extensions for screw- or blade piles which overcome, or at least ameliorate, the 20 problems with existing piles. [0014] Other preferred objects will become apparent from the following description. SUMMARY OF THE INVENTION: 25 [0015] In one aspect, the present invention resides in an extension for a pile of the type having a pile shaft with a driving head at an upper end of the shaft when in use, the extension including: a body shaft; a driving head at an upper end of the shaft, when in use; and 30 a connecting head at a lower end of the shaft and arranged for connection to a driving head of the shaft of the pile or to a driving head of a similar extension.

3 [0016] Preferably, the driving head is of the same configuration as the driving head of the pile; has a plate-like body, secured to the upper end of the shaft; and a bore through the body co-axial with the longitudinal axis of the shaft. 5 [0017] Preferably, the bore is screw-threaded; but may have an alternative configuration for (preferably releasable) engagement with the connecting head of a similar extension, or by a driving member of a rotary pile-driving apparatus. [0018] Preferably, the connecting head has a plate-like body with an 10 external periphery configured to be engageable by a tool, such as a wrench or spanner. [0019] Preferably, a shank extends from an outer face of the connecting head, coaxially-aligned with a central axis of the shaft; and the shank is externally screw-threaded, or otherwise configured, for receipt in the bore 15 and releasable engagement with a driving head on the pile or on a similar extension. (The alternative configurations may include a bayonet -type connection or a shank with a transverse head, the transverse head being insert able through aligned slots extending from the bore of the driving head and engageable with stops or abutments on the underside of the 20 driving head body.) [0020] Preferably, the shaft is tubular; and may have external faces or formation(s) engageable by a wrench, spanner or other tool to secure the extension to, or to release the extension from, the pile or the similar extension. 25 [0021] Other preferred features of the present invention will become apparent from the following description. BRIEF DESCRIPTION OF THE DRAWINGS: [0022] To enable the invention to be fully understood, and to enable the 30 skilled addressee to put the invention into practice, a number of preferred embodiments will now be described, with reference to the accompanying illustrations, in which: 4 FIG. 1 is a schematic side elevation view of a blade pile provided with an extension of a first embodiment in accordance with the present invention; FIG. 2 is a similar view of the extension on a larger scale; FIG. 3 is a top plan view of a driving head for the extension; and 5 FIGS. 4 and 5 are respective side elevational and sectional side views of the driving head. [0023] NB: Any annotations on the drawings are by way of illustration only, and are not limiting to, or form part of, the present invention. 10 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS: [0024] A blade pile 10, as illustrated in FIG. 1, has a tubular (circular) shaft 20, with a metal wall 21 surrounding a central bore 22. The metal wall 21 may be e.g. 4mm-8mm thick, and formed from high-tensile steel. [0025] A square drive head 30, with a screw-threaded bore 31, is welded 15 to the upper end of the shaft 20; while a cutting comb 40, or other suitable digging formation, is welded to the lower end of the shaft 20. [0026] The blade pile 10 is provided with a pair of blades 50, where the blades are diametrically-opposed and are of opposite pitch e.g. at 10* 200, more preferably 15*-170 to the perpendicular to the central axis 23 of 20 the shaft 20. [0027] The blades 50 are mounted on the shaft 20 for rotation in the clock-wise direction, when the blade pile 10 is being driven into the ground (not shown) by a suitable driving apparatus (also not shown) engaged with the square drive head 30. 25 [0028] The blade pile 10 is provided with an extension 60, in accordance with the present invention. [0029] The extension 60 has a tubular shaft 70 of similar construction to the blade pile shaft 20; and a driving head 80, at the upper end of the shaft 70, of the same configuration as the driving head 30 of the blade 30 pile 10. The driving head 80 is continuously welded around the junction of the shaft 70 and the driving head 80, and the latter has a screw-threaded bore 81 co-axially aligned with the central axis of the shaft 70.

5 [0030] A connecting head 90 has a substantially-planar body 91, of similar configuration to the driving head 80, continuously welded at the junction of the planar body 91 and the lower end of the shaft 70. [0031] A connecting shank 92 has a screw-threaded periphery 93, and 5 extends from the planar body 91 coaxially aligned with the central axis of the shaft 70. The connecting shank 92 is screw-threadably engageable in the bore 31 in the driving head 30 of the blade pile 1 (or in the bore 81 of driving head of a similar extension 60.) [0032] A plate 94 may be welded to the inner end of the connecting shank 10 92 and the inner face of the body 91 of the connecting head 90, to increase the strength of the latter. [0033] Typically, the extension 60 will be connected to the blade pile 10 (or a similar extension 60) by screw-threaded engagement of the connector shank 92 in the bore 31 (or bore 81) and the adjacent faces of 15 the connector head 90 & driving head 30 (or 80) are brought into firm contact. To assist the extension 60 being rotated relative to the blade pile 10, or the similar extension, flats or other faces / formations, may be provided on the exterior of the shaft 70 for engagement by wrench(es), spanner(s) or like tools. These tools may also engage the periphery of the 20 driving head 80. [0034] The skilled addressee will appreciate that one, or more, extensions 60 can be secured to the shaft 20 of the blade pile 10, so that the blades 50 can be engaged / anchored in higher-strength soils at depths greater than the length of the shaft 20 of the blade pile 10. 25 [0035] While a blade pile 10 has been illustrated in FIG. 1, the extension 90 of the present invention can be employed with screw piles. [0036] As the shaft 70 and driving head 80 have the same configuration as the shaft 20 and driving head 30 of the blade pile 10, they can be manufactured from the same respective materials. 30 [0037] The extension 60 can have alternative shapes for shaft 70, including square, hexagonal and octagonal. Similarly, the driving head 80 & connecting head 90 can have hexagonal or other shaped peripheries.

6 [0038] While a screw-threaded connection between the extension 60 and blade pile 10 is preferred, the skilled addressee will appreciate that other releasable connections, which allow a rotational driving force to be transmitted from the extension 60 to the blade pile 10 (or similar extension 5 60), are available. One example is a bayonet-type connection. Another example employs a head on the shank which passes through the bore in the driving head (e.g. via diametrically-opposed recesses), where the head engages abutment(s) or stop(s) on the inner face of the driving head, to allow the connecting head to transmit a rotational driving force to 10 the driving head in one direction of rotation. [0039] When the extension 60 is installed, it is fully sealed from the ingress of moisture and/or oxygen. The shank 92 of a similar extension 60 immediately above the extension 60; or the shank (of similar configuration) of a load bearing plate (for a building slab or the like) seals 15 the upper end of the shaft 70; while the lower end of the shaft 70 is sealed by the planar body 91 and shank 92 of the connecting head 90. NB: There are no holes provided in the shaft 70. By sealing the interior of the shaft 70 from the surrounding soil, any internal corrosion of the extension 60 is eliminated, or at least considerably minimised, to extend the design life of 20 the extension by 100% e.g. from 50 years to 100 years. [0040] In addition, by welding the driving head 80 and connector head 90 to the shaft 70, the torque capacity of the extension 60 is increased, with the heads 80, 90 operating as additional braces to the shaft 70. [0041] Various changes and modifications may be made to the 25 embodiments described and illustrated without departing from the present invention. 30

Claims (5)

1. An extension for a pile of the type having a pile shaft with a driving head at an upper end of the shaft when in use, the extension including: 5 a body shaft; a driving head at an upper end of the shaft, when in use; and a connecting head at a lower end of the shaft and arranged for connection to a driving head of the shaft of the pile or to a driving head of a similar extension. 10

2. The extension of claim 1, wherein: the driving head has a plate-like body, secured to the upper end of the shaft; and a bore through the body co-axial with the longitudinal axis of the shaft; and optionally, the bore is screw-threaded, or has an alternative configuration 15 for releasable engagement with the connecting head of a similar extension, or by a driving member of a rotary pile-driving apparatus.

3. The extension of claim or claim 2, wherein: the connecting head has a plate-like body; a shank extends from an outer face of the connecting head, coaxially 20 aligned with a central axis of the shaft; and the shank is externally screw-threaded, or otherwise configured, for receipt in the bore and releasable engagement with a driving head on the pile or on a similar extension.

4. The extension of any one of claims 1 to 3, wherein: 25 the shaft is tubular; and optionally, the shaft has external faces or formation(s) engageable by a wrench, spanner or other tool to secure the extension to, or to release the extension from, the pile or the similar extension.

5. The combination of a screw-pile or blade-pile with at least one 30 extension as claimed in any one of claims 1 to 4.