Blade pile drive head and blade pile system

Abstract

A blade pile drive head (100) and blade pile system include a hollow body (105) having a longitudinal axis (205) and defines a socket (210) for a drive shaft. A distal end of the body opposite the socket defines an attack bit (120), and at least one blade (110) extends away from the longitudinal axis. A blade base (135) is attached to the body (105) in a first axial region ("A") along the longitudinal axis (205). The socket (210) extends into the body (105) in a second axial region ("B") along the longitudinal axis (205), and at least some portion of the first axial region ("A") overlaps along the longitudinal axis (205) with at least some portion of the second axial region ("B").

Description

Blade Pile Drive Head and Blade Pile SystemFIELD OF THE INVENTION

[0001] The present invention relates generally to screw pile and blade pile systems. In particular, although not exclusively, the invention relates to a blade pile drive head and associated blade pile system, including effective connection to a blade pile elongated main shaft.BACKGROUND

[0002] Screw piles and blade piles are commonly used in the construction of buildings, solar farms and other structures. A typical screw / blade pile comprises a shaft, normally made from mild steel or a higher strength steel. A helical screw or blade is attached to the shaft. In order to insert the screw pile into the ground, the screw pile is rotated and pressed downwardly which causes the helix or blade to bite into the ground and to screw into the ground. Once the pile has been properly inserted into the ground, the weight borne by the pile is distributed from the helical screw or blade into the earth that lies underneath the screw / blade. Further, the overburden pressure of the earth positioned above the screw / blade assists in resisting any lifting forces applied to the pile and thereby assists in maintaining the pile in the ground.

[0003] Conventional screw / blade piles comprise a single helical screw or a pair of blades. The helical screw has a single leading edge that moves through and breaks the earth as the pile is screwed into the ground. Blade piles have two leading edges on the blades, which extend generally perpendicularly to the outer periphery of the blades (when viewed from above). As the shaft is normally cylindrical in shape, the leading edges of the blades may be considered to extend outwardly from the shaft in the radial direction.

[0004] Australian patent application number 2010202047 and Australian innovation patent number 2011100820, the entire contents of which are herein incorporated by reference, describe a screw pile comprising a shaft, at least two blades extending outwardly from the shaft, each blade having a leading edge that contacts earth as the screw pile is screwed into the ground, the leading edges including at least a portion extending in a direction that is non-perpendicular to an outer periphery of the shaft (when viewed from above).

[0005] Alternatively, the screw pile described in the above referenced patent application and innovation patent comprises a screw pile comprising a shaft, at least two blades extending outwardly from the shaft, each blade having a leading edge that contacts earth as the screw pile is screwed into the ground. The leading edges include a swept back portion and four pointed tips that strike rock out of phase to each other and are therefore adapted to deflect and vibrate the pile head through rocks that come into contact with the leading edges during insertion of the screw pile into the ground. The screw pile may comprise two blades in the form of angled plates. The angled plates may be mounted to the shaft. The angled plates may be mounted to the shaft, for example, by welding. Alternatively, the angled plates may be integrally formed with the shaft. The angled plates may be generally flat angled plates. The angled plates may have opposite pitch to each other. For example, when viewed from side on, one angled plate may extend downwardly from left to right while the other angled plate may extend downwardly from right to left.

[0006] Using angled blades instead of a helical screw often makes manufacture of a screw pile more simple. Further, each angled blade counteracts the forces applied by the other angled blade during insertion of the screw pile, thereby resulting in the screw pile being properly counter balanced from the two leading edges on opposite sides of the pile shaft, which helps prevent the pile ‘walking off’ position and maintain critical positional design tolerances.

[0007] Large-scale solar energy installations typically comprise a number of solar photovoltaic cells or solar collectors (such as solar collectors that areused to heat water to produce steam). In some solar energy installations, the solar photovoltaic cells or solar collectors track the sun during the day in order to maximise the amount of solar energy collected. In order to achieve this, some installations mount a number of solar photovoltaic cells or solar collectors to large drive beams and the drive beams are slowly rotated during the day to track the movement of the sun. The drive beams and associated structure must be firmly mounted in the ground in a number of locations in order to firmly support the drive beam and stop or minimise distortion of the drive beam during use. Thus, many large-scale solar energy installations mount the supporting structure for the drive beams to concrete or driven steel beam foundations.

[0008] The inventor of the present application is also a named inventor on granted US patent no. 10,876,268 B2 (the ‘268 patent), the entire contents of which are hereby incorporated by reference in their entirety into the present specification. The ‘268 patent discloses an improvement in blade pile design, including a lower cylindrical member that can rotate relative to a main shaft. In this manner, the blades can be rotated, such as by a drive tool, during installation of the screw pile into the ground while the square or rectangular hollow shaft can simply be pulled into the ground by the blades without requiring that the hollow shaft be rotated.

[0009] However, to enable wider and more efficient applications of screw / blade pile technology, there remains a need for lighter, stronger and / or less expensive screw / blade pile designs.

[0010] For example, some blade pile designs include numerous expensive welding and machining operations to manufacture a new drive head. Existing alternatives to such welded drive heads include integral forged drive heads; however, such forged drive heads generally are very heavy due to the large amounts of steel, and thus added cost, needed to withstand the high torque and bending forces applied to the drive head body and blades during installation in often rocky or hard soils. Large solar panel farms can require hundreds of thousands of individual blade piles, and thus even minor cost and material savings per blade pile can be very beneficial.

[0011] Therefore, there is a need for a further improved blade pile drive head.

[0012] It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.OBJECT OF THE INVENTION

[0013] It is an object of the present invention to overcome and / or alleviate one or more of the disadvantages of the prior art or provide the consumer with a useful or commercial choice.SUMMARY OF THE INVENTION

[0014] In one aspect, although it need not be the only or the broadest aspect, the invention resides in a blade pile drive head, comprising: a hollow body having a longitudinal axis and defining a socket for a drive shaft, wherein a distal end of the body opposite the socket defines an attack bit; and at least one blade extending away from the longitudinal axis, and having a blade base attached to the body in a first axial region along the longitudinal axis; wherein the socket extends into the body in a second axial region along the longitudinal axis, and at least some portion of the first axial region overlaps along the longitudinal axis with at least some portion of the second axial region.

[0015] Preferably, the hollow body and at least one blade are cast as a single integral part.

[0016] Preferably, the at least one blade comprises a leading bevelled edge for cutting into ground below the drive head during installation of acorresponding blade pile, and a reversing bevelled edge for cutting into ground above the drive head during removal of the corresponding blade pile.

[0017] Preferably, the attack bit comprises at least one flute that extends along the longitudinal axis for the removal of drilling spoil.

[0018] Preferably, the at least one blade consists of a pair of blades.

[0019] Preferably, a thickness of the at least one blade reduces progressively outward from a base of the blade to a curved centroid line near a centre of the blade.

[0020] Preferably, a base of the at least one blade includes an angled radius to ensure a robust attachment of the blade to the body and, in use, to deflect and flow soil around the drive head.

[0021] Preferably, a top end of the socket is keyed and angled outward to guide and receive a distal end of the drive shaft.

[0022] Preferably, a top end of the socket defines a cylindrical collar for receiving a distal end of a cylindrical shaft of a blade pile.

[0023] Preferably, the cylindrical collar comprises a plurality of holes for receiving fasteners to lock the drive head to the distal end of the cylindrical shaft of the blade pile.

[0024] Preferably, the body comprises placement / torque lugs positioned on a shoulder in the socket, whereby in an assembled blade pile notches on the cylindrical shaft of the blade pile receive the placement / torque lugs to prevent rotation of the cylindrical shaft relative to the drive head.

[0025] According to an alternative aspect, the invention resides in a blade pile system, comprising: the blade pile drive head as described above; a hollow elongate shaft; and a connector;wherein the blade pile drive head is rotatably mounted to the hollow elongate shaft, the connector being joined to the drive head, the connector having a portion that is retained within the hollow elongate shaft, and the connector being rotatable relative to the hollow elongate shaft.

[0026] Preferably, the hollow elongate shaft comprises a shaft having a shape of a polygonal prism, a square hollow section, or a rectangular hollow section.

[0027] Preferably, the hollow elongate shaft has a circular cross-section for at least a part of its length.

[0028] Preferably, the drive head further comprises one or more projections to sweep material away from an underside of the hollow elongate shaft or for removing material away from a region near an interface between the hollow elongate shaft and the drive head during insertion of the screw pile into the ground.

[0029] Preferably, the connector is welded into a distal end of the elongate shaft.

[0030] Preferably, the connector is connected to a distal end of the elongate shaft without using welding.

[0031] According to another alternative aspect, the invention resides in a blade pile system, comprising: the blade pile drive head as described above; and a hollow elongate shaft rigidly connected to the hollow body adjacent the socket.

[0032] Preferably the hollow elongate shaft is rigidly connected to the hollow body using placement / torque lugs on the body that are received in notches on the shaft, and fasteners are positioned through the shaft into the body.

[0033] Preferably, the blade pile system comprises, during installation ofthe blade pile, a drive shaft extending through the hollow elongate shaft and engaging the socket of the drive head, whereby rotation of the drive head rotates the drive shaft.BRIEF SUMMARY OF THE DRAWINGS

[0034] To assist in understanding the invention and to enable a person skilled in the art to put the invention into practical effect, preferred embodiments of the invention are described below by way of example only with reference to the accompanying drawings, in which:

[0035] FIG. 1 is a side view of a blade pile drive head for rotational attachment to a main shaft of a blade pile, according to an embodiment of the present invention.

[0036] FIG. 2 is a cross-sectional side view of the blade pile drive head of FIG. 1.

[0037] FIG. 3 is a top perspective view of the blade pile drive head of FIG. 1.

[0038] FIG. 4 is a further side view of the blade pile drive head of FIG. 1 .

[0039] FIG. 5 is a side view of an alternative embodiment of the present invention, including a blade pile drive head for rigid attachment to a main shaft of a blade pile.

[0040] FIG. 6 is a cross-sectional side view of the blade pile drive head of FIG. 5.

[0041] FIG. 7 is a top perspective view of the blade pile drive head of FIG. 5.

[0042] FIG. 8 is a further cross-sectional side view of the blade pile drive head of FIG. 5.

[0043] FIG. 9 is a side view of a completed blade pile system, including a main shaft and the blade pile drive head of FIG. 1 , according to some embodiments of the present invention.

[0044] FIG. 10 is a side perspective view of the blade pile system of FIG. 9.

[0045] FIG. 11 is a side view of a completed blade pile system, including a main shaft and the blade pile drive head of FIG. 5, according to some embodiments of the present invention.

[0046] FIG. 12 is a side perspective view of the blade pile system of FIG. 1 1.

[0047] FIG. 13 is a perspective view of a two-piece, weld-free, control plate system, according to an alternative embodiment of the present invention.

[0048] FIG. 14 is a top view of the control plate system of FIG. 13, showing the system installed on the end of a main shaft.

[0049] FIG. 15 is front view of the blade pile drive head of FIG. 1 installed on a main shaft using the control plate system of FIG. 13.

[0050] FIG. 16 is side view of the blade pile drive head of FIG. 1 installed on a main shaft using the control plate system of FIG. 13.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0051] The present invention relates to a blade pile drive head and a blade pile system. Elements of the invention are illustrated in concise outline form in the drawings, showing only those specific details that are necessary to understanding the embodiments of the present invention, but so as not to clutter the disclosure with excessive detail that will be obvious to those of ordinary skill in the art in light of the present description.

[0052] In this patent specification, adjectives such as first and second, left and right, above and below, top and bottom, upper and lower, front and back, etc., are used solely to define one element or method step from another element or method step without necessarily requiring a specific relative position or sequence that is described by the adjectives. Words such as “comprises” or “includes” are not used to define an exclusive set of elements or method steps. Rather, such words merely define a minimum set of elements or method steps included in a particular embodiment of the present invention.

[0053] According to one aspect, the present invention is a blade pile drive head, comprising: a hollow body having a longitudinal axis and defining a socket for a drive shaft, wherein a distal end of the body opposite the socket defines an attack bit; and at least one blade extending away from the longitudinal axis, and having a blade base attached to the body in a first axial region along the longitudinal axis; wherein the socket extends into the body in a second axial region along the longitudinal axis, and at least some portion of the first axial region overlaps along the longitudinal axis with at least some portion of the second axial region.

[0054] Advantages of some embodiments of the present invention include a much lighter and robust drive head design that can be cast in a single integral part.

[0055] Also, according to some embodiments, a blade pile drive head can be manufactured and installed on a blade pile with little or no welding, thus reducing manufacturing costs.

[0056] Also, according to some embodiments, the drive shaft socket extends deep into the body of the drive head so that it is directly adjacent the blades. That can enable both a lighter and stronger design.

[0057] Further, some embodiments include leading bevelled edges for cutting into ground below the drive head during installation of a corresponding blade pile, and reversing bevelled edges for cutting into ground above the drive head during removal of the corresponding blade pile. Such a feature can assist substantially in the environmental restoration, clean up and site remediation required when installed blade piles need to be removed.

[0058] Those skilled in the art will appreciate that not all of the above advantages are necessarily included in all embodiments of the present invention.

[0059] FIG. 1 is a side view of a blade pile drive head 100, according to an embodiment of the present invention. The drive head 100 can be cast as a single integral part, and includes a hollow body 105 from which extends a first blade 110 and a second blade 115. A distal end of the body 105 defines an attack bit 120 that, during installation of a blade pile, cuts into the ground first.

[0060] The first blade 110 and second blade 115 each comprise a leading bevelled edge 125 for cutting into ground below the drive head 100 during installation of a corresponding blade pile. The bevelled edge 125 is adjacent to a transverse bevelled edge 125a that extends outward from the body 105. Both blades 110, 115 also include a reversing bevelled edges 130 and transverse bevelled edges 135a, for cutting into ground above the drive head 100 during removal of the corresponding blade pile. The transverse bevelled edge 125a, 130a of each blade 110, 115 extends outward from a blade base 135, 140. Each blade base 135, 140 includes an angled radius to ensure a robust attachment of the blades 110, 115 to the body 105 and to deflect and flow soil around the drive head 100.

[0061] A thickness of each blade 110, 115 reduces progressively outward from the base 135, 140 to a curved centroid line 145, 150 at the centre of the blades 110, 115. That provides progressive reinforcing to mitigate bending. The centroid lines 145, 150 represent a ‘peak’ focal point of frictional mechanical forces during pile installation, and long term static vertical load bending forces that are also transferred via the blades 110, 115 intoengaged / surrounding load bearing soils. The blades 110, 115 then maintain a constant thickness from the centroid lines 145, 150 to their outer edges.

[0062] FIG. 2 is a cross-sectional side view of the blade pile drive head 100. An upper side wall 200 is centred around a longitudinal axis 205 and defines a socket 210 for receiving a drive shaft.

[0063] As shown, the base 135, 140 of each blade 110, 115 is attached to the body 105 in a first axial region “A” that extends along the longitudinal axis 205. The socket 210 extends into the body 105 in a second axial region “B” along the longitudinal axis 205. According to many embodiments, and as shown in FIG. 2, at least some portion of the first axial region “A” overlaps along the longitudinal axis 205 with at least some portion of the second axial region “B”. That enables torque from a draft shaft inserted into the socket 210 to be applied directly through to each blade 110, 115, while reducing the amount of material required to cast the drive head 100, and increasing the durability of the blades 110, 115.

[0064] The socket 210 includes upper edges 215 that taper outward to assist in guiding a drive shaft into the socket 210. Further, the body 105 defines a bearing journal 220 for receiving a control plate that functions as a bearing and rotatably attaches the blade pile drive head 100 to a main shaft of a pile.

[0065] FIG. 3 is a top perspective view of the blade pile drive head 100, showing hexagonal sides of the socket 210, including the tapered upper edges 215. Also, a series of projections 300 extend outward from an upper end of the body 105 to define a sweeper ring, which may define an elliptical outer shape. As the drive head 100 is rotated during insertion of a blade pile into the ground, the projections 300 assist in sweeping away material and debris from the upper end of the body 105, which effectively clears a path for the elongated shaft of the blade pile as it is drawn into the ground. Further, the tips of the projections 300 are bevelled at an angle that is designed to optimise outward deflection of soils out from under the lower distal end of a pile shaft. Thus, such a sweeper ring can prevent ‘pile refusal’ fromaccumulated soil and resultant soil pressure build up during installation, which can help ensure the smooth advancement of the pile during installation.

[0066] FIG. 4 is a further side view of the blade pile drive head 100. If a screw pile is to be inserted into rocky or hard ground, the attack bit 120 of the drive head 100 can assist in cutting through or breaking through the rocky or hard ground. During installation of a blade pile, the attack bit 120 can effectively drill a pilot hole, and when the screw pile is placed in a vertical position and moved into contact with the ground during the initial stages of installation, the pile is less likely to tip away from the vertical orientation, meaning that the correct orientation and position of the pile is easier to maintain during installation. That can improve installation tolerances.

[0067] As shown, the attack bit 120 comprises at least one flute 400 that extends along the longitudinal axis 205 of the drive head 100, and can assist in the deflection of drilled spoil. Those skilled in the art will appreciate that the attack bit 120 can comprise various alternative designs and materials depending, for example, on the application and the hardness of the rock or soil in which the drive head 100 will be installed.

[0068] Alternative embodiments of the present invention include a blade pile drive head that can be rigidly attached to a rotating main shaft of a blade pile. Thus, where the blade pile drive head 100 is designed for attachment to a rotatable connector or hub, as described in detail in US patent no. 10,876,268 B2, advantages of the present invention also can be obtained in such embodiments having a drive head rigidly attached to a blade pile main shaft.

[0069] FIG. 5 is a side view of such an alternative embodiment of the present invention, including a blade pile drive head 500 for rigid attachment to a main shaft of a blade pile. Similar to the drive head 100, the drive head 500 also can be cast as a single integral part, and includes a hollow body 505 from which extends a first blade 510 and a second blade 515. A distal end of the body 505 defines an attack bit 520 that, during installation of a blade pile, cuts into the ground first.

[0070] The first blade 510 and second blade 515 can be identical to the blades 1 10, 115 described above. Thus, the first blade 510 and second blade 515 each comprise leading bevelled edges 525 for cutting into ground below the drive head 500 during installation of a corresponding blade pile. Both blades 510, 515 also include reversing bevelled edges 530 for cutting into ground above the drive head 500 during removal of the corresponding blade pile. A base 535 of each blade 510, 515 is curved to ensure a robust attachment to the body 505 of the drive head 500.

[0071] FIG. 6 is a cross-sectional side view of the blade pile drive head 500. An upper side wall 600 of the drive head 500 is centred around a longitudinal axis 605 and defines a socket 610 for receiving a drive shaft. The upper side wall 600 further functions as a collar for rigidly connecting a main shaft of a blade pile to the drive head 500.

[0072] During use, a drive shaft is inserted down the main shaft of the blade pile and a hexagonal distal end of the drive shaft engages the six side walls 625 of the hexagonal portion of the socket 610, enabling the drive head 500 and main shaft to be rotated together into the ground. As described further below, the main shaft is secured to the drive head 500 by two placement / torque lugs 615 and Tek screws threaded through side holes 620.

[0073] FIG. 7 is a top perspective view of the blade pile drive head 500.As shown, the upper side wall 600 defines a cylindrical collar for receiving and securing a main shaft of a blade pile.

[0074] FIG. 8 is a further cross-sectional side view of the blade pile drive head 500. To assemble a complete blade pile, a relatively thin-walled main shaft of a blade pile (e.g., see FIG. 12) is received in the socket 610, where the main shaft rests on an annular shoulder 800 defined on an inner diameter of the socket 610. The two placement / torque lugs 615 are positioned on either side of the shoulder 800. Two corresponding notches spaced 180 degrees apart are cut into the distal end of the main shaft and receive the placement / torque lugs 615. The main pile shaft then can be locked to the drive head 500 by placing fasteners such as Tek screws through the side holes 620of the upper side wall 600 and into the main shaft. Accordingly, when a drive shaft extends through the main pile and engages the socket 610, rotation of the drive shaft turns the drive head 500, and sides of the placement / torque lugs 615 engage the notches in the main shaft to turn the main shaft. Generally the only turning forces experienced by the pile main shaft are from soil skin friction during installation, because all the pile install torque forces are applied to the hexagonal portion of the socket 610. Thus, such low-level soil skin friction forces applied to the pile main shaft during installation are shared by the lugs 615 and the Tek screws.

[0075] As described above, the blade pile drive head 100 and the blade pile drive head 500 can be used with alternative types of blade pile main shafts to define a blade pile system. Examples of such systems are illustrated in FIGs. 9 to 12.

[0076] FIG. 9 is a side view of a completed blade pile system 900, including a main shaft 905 and the blade pile drive head 100, according to some embodiments of the present invention. As described in US patent no. 10,876,268 B2 the entire contents of which are incorporated by reference herein, the main shaft 905 can be rotatably connected to the drive head 100 via a two-piece steel control plate 910 that surrounds the bearing journal 220 of the drive head 100. The control plate 910 is thus installed immediately above the sweeper ring projections 300, and is welded into place around the drive head 100, with the weld locations and size guided by pre-set book- ended bevelled edges. Then, the entire assembly of the control plate 910 and drive head 100 is welded into the base of the main shaft 905. The control plate 910 thus operates as a bearing, enabling the main shaft 905 of the pile system 900 to be effectively pulled into the ground without rotation. The main shaft 905 is pulled through the soil or earth that has been disturbed by the rotating blades 1 10, 1 15 during installation. It is believed that moving the main shaft 905 downwardly through the disturbed earth causes some displacement of the disturbed earth and helps the disturbed earth re-compact and settle against the outer walls of the main shaft 905.

[0077] FIG. 10 is a side perspective view of the blade pile system 900.

[0078] FIG. 11 is a side view of a completed blade pile system 1100, including a main shaft 1 105 and the blade pile drive head 500, according to some embodiments of the present invention. As described above, the main shaft 1105 is rigidly connected to the blade pile drive head 500, and thus during installation both the main shaft 1105 and the drive head 500 rotate together into the ground.

[0079] FIG. 12 is a side perspective view of the blade pile system 1100.

[0080] FIGs. 13, 14, 15 and 16 illustrate an alternative, weld-free method of rotatably connecting the blade pile drive head 100 to a blade pile main shaft, such as the rectangular main shaft 905 shown in FIGs. 9 and 10.

[0081] FIG. 13 is a perspective view of a two-piece, weld-free, control plate system 1300, according to an embodiment of the present invention. The system 1300 is an alternative to welding together the two-piece steel control plate 910 that surrounds the bearing journal 220 of the drive head 100, as described above. Instead, using the control plate system 1300 a first control plate half 1305 and a second control plate half 1310 are simply installed adjacent to each other, without welding, around the bearing journal 220 of the blade pile drive head 100. The two halves 1305, 1310 can be interlocked together around the bearing journal 220 using linear lock hook keyways 1315, 1320.

[0082] FIG. 14 is a top view of the control plate system 1300, showing the system 1300 installed on the end of the main shaft 905. As shown, the assembled control plate system 1300 is simply slid onto the distal end of the rectangular main shaft 905, where overlap plates 1325, 1330 fit against the outside surfaces of the wide faces of the main shaft 905. Tek screws then can be threaded through the four (4) holes 1335 on each of the overlap plates 1325, 1330 to secure the assembled control plate system 1300 to the main shaft 905.

[0083] Bracing elements of the two halves 1305, 1310 that form the keyways 1315, 1320 are braced against the inside surfaces of the narrow faces of the main shaft 905. The dashed line in FIG. 13 shows the installedposition of the main shaft 905 on the control plate system 1300, where the main shaft walls are inboard of the overlap plates 1325, 1330 and outboard of the bracing elements of the keyways 1315, 1320.

[0084] FIGs. 15 and 16 are front and side views, respectively, of the blade pile drive head 100 installed on the main shaft 905 using the control plate system 1300.

[0085] Those skilled in the art will appreciate that embodiments of the present invention can be manufactured from a wide range of materials, including sand cast or die cast steel.

[0086] Reference throughout this specification to ‘one embodiment’ or ‘an embodiment’ means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases ‘in one embodiment’ or ‘in an embodiment’ in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

[0087] The above description of various embodiments of the present invention is provided for purposes of description to one of ordinary skill in the related art. It is not intended to be exhaustive or to limit the invention to a single disclosed embodiment. Numerous alternatives and variations to the present invention will be apparent to those skilled in the art of the above teaching. Accordingly, while some alternative embodiments have been discussed specifically, other embodiments will be apparent or relatively easily developed by those of ordinary skill in the art. Accordingly, this patent specification is intended to embrace all alternatives, modifications and variations of the present invention that have been discussed herein, and other embodiments that fall within the spirit and scope of the above-described invention.

Claims

CLAIMSWe claim:1 . A blade pile drive head, comprising: a hollow body having a longitudinal axis and defining a socket for a drive shaft, wherein a distal end of the body opposite the socket defines an attack bit; and at least one blade extending away from the longitudinal axis, and having a blade base attached to the body in a first axial region along the longitudinal axis; wherein the socket extends into the body in a second axial region along the longitudinal axis, and at least some portion of the first axial region overlaps along the longitudinal axis with at least some portion of the second axial region.

2. The blade pile drive head of claim 1 , wherein the hollow body and at least one blade are cast as a single integral part.

3. The blade pile drive head of claim 1 , wherein the at least one blade comprises a leading bevelled edge for cutting into ground below the drive head during installation of a corresponding blade pile, and a reversing bevelled edge for cutting into ground above the drive head during removal of the corresponding blade pile.

4. The blade pile drive head of claim 1 , wherein the attack bit comprises at least one flute that extends along the longitudinal axis for the removal of drilling spoil.

5. The blade pile drive head of claim 1 , wherein the at least one blade consists of a pair of blades.

6. The blade pile drive head of claim 1 , wherein a thickness of the at least one blade reduces progressively outward from a base of the blade to a curved centroid line near a centre of the blade.

7. The blade pile drive head of claim 1 , wherein a base of the at least one blade includes an angled radius to ensure a robust attachment of the blade to the body and, in use, to deflect and flow soil around the drive head.

8. The blade pile drive head of claim 1 , wherein a top end of the socket is keyed and angled outward to guide and receive a distal end of the drive shaft.

9. The blade pile drive head of claim 1 , wherein a top end of the socket defines a cylindrical collar for receiving a distal end of a cylindrical shaft of a blade pile.

10. The blade pile drive head of claim 9, wherein the cylindrical collar comprises a plurality of holes for receiving fasteners to lock the drive head to the distal end of the cylindrical shaft of the blade pile.11 . The blade pile drive head of claim 9, wherein the body comprises placement / torque lugs positioned on a shoulder in the socket, whereby in an assembled blade pile notches on the cylindrical shaft of the blade pile receive the placement / torque lugs to prevent rotation of the cylindrical shaft relative to the drive head.

12. A blade pile system, comprising: the blade pile drive head of claim 1 ; a hollow elongate shaft; and a connector; wherein the blade pile drive head is rotatably mounted to the hollow elongate shaft, the connector being joined to the drive head, the connector having a portion that is retained within the hollow elongate shaft, and the connector being rotatable relative to the hollow elongate shaft.

13. The blade pile system of claim 12, wherein the hollow elongate shaft comprises a shaft having a shape of a polygonal prism, a square hollow section, or a rectangular hollow section.

14. The blade pile system of claim 12, wherein the hollow elongate shaft has a circular cross-section for at least a part of its length.

15. The blade pile system of claim 12, wherein the drive head further comprises one or more projections to sweep material away from an underside of the hollow elongate shaft or for removing material away from a region near an interface between the hollow elongate shaft and the drive head during insertion of the screw pile into the ground.

16. The blade pile system of claim 12, wherein the connector is welded into a distal end of the elongate shaft.

17. The blade pile system of claim 12, wherein the connector is connected to a distal end of the elongate shaft without using welding.

18. A blade pile system, comprising: the blade pile drive head of claim 1 ; and a hollow elongate shaft rigidly connected to the hollow body adjacent the socket.

19. The blade pile system of claim 18, wherein the hollow elongate shaft is rigidly connected to the hollow body using placement / torque lugs on the body that are received in notches on the shaft, and fasteners are positioned through the shaft into the body.

20. The blade pile system of claim 12 or 18, wherein during installation of the blade pile a drive shaft extends through the hollow elongate shaft and engages the socket of the drive head, whereby rotation of the drive head rotates the drive shaft.

Images