Abstract
There is disclosed a lifting attachment for a building unit comprising sheeting and a support structure over which the sheeting is disposed, the attachment being configured such that it can be connected to or integrated into the support structure and comprising a lifting anchor that, when the attachment is so connected or integrated, is engageable by a component for lifting the unit such that a releasable interconnection between the component and the support structure passes through an opening in the sheeting.
Claims
1. A building unit comprising: a support structure including a chord and a web member transverse to the chord; sheeting disposed over the support structure, wherein the support structure and the sheeting define an opening extending through the support structure and the sheeting; and a lifting anchor including: a base including a first wall and a second wall transverse to the first wall, the base mounted to the support structure via at least one of the first and second walls, and a lifting-component engager sized and shaped to releasably connect to a lifting component for lifting the building unit, wherein the lifting-component engager is movable from a recessed position to an extended position relative to the sheeting, wherein the lifting-component engager extends in the opening but not above the sheeting when in the recessed position, wherein the lifting-component engager extends through the opening above the sheeting and is engagable by the lifting component when in the extended position.
2. The building unit of claim 1, wherein the base includes an L-shaped support member including the first wall and the second wall.
3. The building unit of claim 1, wherein the first wall is attached to the chord and the second wall is attached to the web member.
4. The building unit of claim 1, wherein lifting-component engager is threadably connectable to the base such that the lifting-component engager is movable relative to the base via rotation of the lifting-component engager relative to the base.
5. The building unit of claim 1, wherein the lifting component engager is insertable through the base when the base is in a first position and engagable with a bottom surface of the base when the base is in a second, different position.
6. The building unit of claim 1, wherein the lifting-component engager includes a head engagable by the lifting component when the lifting component engager is in the extended position.
7. The building unit of claim 6, wherein the head is releasably connectable to a part of the lifting-component engager after insertion of the head into the lifting component.
8. A method for forming a building unit, the method comprising: attaching sheeting to and above a support structure; forming an opening through the support structure and the sheeting; and mounting a lifting attachment to the support structure such that a movable lifting-component engager of a lifting anchor of the lifting attachment extends through the opening and above the sheeting when the lifting-component engager is in an extended position, and the lifting-component engager extends in the opening but does not extend above the sheeting when the lifting-component engager is in a recessed position, wherein mounting the lifting attachment to the support structure includes attaching a first wall of the lifting anchor to a chord of the support structure and attaching a second wall of the lifting anchor to a web member of the support structure that is transverse to the chord.
9. The method of claim 8, wherein the chord and the web member are perpendicular.
10. A method for forming a building unit, the method comprising: attaching sheeting to and above a support structure; forming an opening through the support structure and the sheeting; and mounting a lifting attachment to the support structure such that a movable lifting-component engager of a lifting anchor of the lifting attachment extends through the opening and above the sheeting when the lifting-component engager is in an extended position, and the lifting-component engager extends in the opening but does not extend above the sheeting when the lifting-component engager is in a recessed position, wherein the lifting anchor includes a base including a first wall and a second wall transverse to the first wall, and which includes mounting the base to the support structure via at least one of the first and second walls such that the lifting anchor is movable relative to the base from the recessed position to the extended position.
11. The method claim 10, wherein the lifting anchor is threadably connectable to the base such that the lifting anchor is movable relative to the base via rotation of the lifting anchor relative to the base.
12. A method for forming a building unit, the method comprising: attaching sheeting to and above a support structure; forming an opening through the support structure and the sheeting; and mounting a lifting attachment to the support structure such that a movable lifting-component engager of a lifting anchor of the lifting attachment extends through the opening and above the sheeting when the lifting-component engager is in an extended position, and the lifting-component engager extends in the opening but does not extend above the sheeting when the lifting-component engager is in a recessed position, wherein the lifting anchor includes a base including a first wall and a second wall transverse to the first wall, and which includes mounting the base mounted to the support structure via at least one of the first and second walls, and which includes inserting the lifting anchor through the base when the base is in a first position and moving the base into a second different position such that lifting anchor engages a bottom surface of the base.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The present disclosure will now be described, by way of non-limiting example only, with reference to the accompanying drawings.
(2) FIGS. 1A to 1C show details of a building unit into which can be incorporated one or more lifting attachments in accordance with one embodiment of the present disclosure.
(3) FIG. 2A shows a lifting attachment according to one embodiment of the present disclosure.
(4) FIGS. 2B and 2C show a base of the attachment of FIG. 2A and an insert forming part of that base respectively.
(5) FIGS. 2D and 2E show how the insert is deformed to form part of the base of FIG. 2B.
(6) FIG. 3 shows details of an attachment embodying the present disclosure engaged by a load ring such that the building unit can be lifted.
(7) FIG. 4A shows a typical lifting clutch engageable with the lifting attachment of FIG. 2A and with lifting attachments according to other embodiments of the present disclosure.
(8) FIG. 4B shows the attachment of FIG. 2A in situ.
(9) FIGS. 4C and 4D show the attachment depicted in FIG. 4B being engaged by a lifting clutch.
(10) FIG. 4E is another view of a typical lifting clutch engageable with the lifting attachment of FIG. 2A and with lifting attachments according to other embodiments of the present disclosure.
(11) FIGS. 5A and 5B show how the attachment of FIG. 2A is installed in the building unit.
(12) FIG. 5C is another view of a typical lifting clutch engaged with the installed lifting attachment shown in FIG. 5A.
(13) FIGS. 6A to 6F show details of a lifting attachment according to another embodiment of the present disclosure and the application of that attachment to the building unit.
(14) FIGS. 7A and 7B show fitting of a plug or cap into an opening in outer sheeting of the building unit to occlude the opening and thus cover a head of an anchor of the attachment of the attachment shown in FIG. 6E, once the unit has been lifted by and disengaged from the lifting clutch.
(15) FIG. 7C shows the application of an overlay to the outer sheeting once the plug or cap has been installed.
(16) FIGS. 8A and 8B show details of an installed attachment in accordance with a further embodiment of the present disclosure.
(17) FIG. 8C shows a variation of the installation shown in FIGS. 8A and 8B, in which a washer is used to distribute loads from a stopper of the anchor into a greater area.
(18) FIG. 9 shows details of an installed attachment according to another embodiment of the present disclosure engaged by another typical lifting clutch.
(19) FIG. 10 shows details of an attachment according to a further embodiment of the present disclosure.
DETAILED DESCRIPTION
(20) The embodiments of the present disclosure provide improvements with respect to lifting of a building unit 100, shown in FIG. 1A, being a panel-like unit that may, for example, be for a ceiling, wall, or floor. The unit 100 may, more particularly, be a floor cassette or panel, a roof module, or a wall panel. Referring also to FIGS. 1B and 1C, the unit 100 comprises spaced apart trusses 110 and sheeting 120 (that may be formed, for example, from particleboard) fixed to and supported on the trusses 110. Each truss 110 comprises parallel top and bottom chords 111 and 112, diagonal webs 113, and at least one transverse or upright web 114. The chords 111 and 112 and/or webs 113 and 114 may be formed, for example, from timber or metal, e.g., steel. Where the chords and webs comprise ones of timber, each truss includes nail plates 115 that reinforce interconnections between the webs 113 and 114 and chords 111 and 112. The unit 100 further comprises at least one strongback 130, likewise able to be formed from timber or metal (e.g., steel), secured to aligned webs 114 of the trusses 110, thereby interconnecting them. Sheeting 120 is secured against upper faces of the top chords 111.
(21) Referring to FIG. 2A, an attachment 1 according to a first embodiment of the present disclosure is designed so as to be applied to the unit 100 so as to render it liftable by a lifting clutch 300, shown in FIGS. 4A and 4E, of the kind commonly used by transport and crane companies, e.g., a Reid Swiflift™ clutch. The attachment 1 comprises a base 10, via which it is mountable to the unit 100 (in a manner that will be described later), and a lifting anchor 30 that is movably connected to the base 10 and defined by a hexagon flange bolt comprising a threaded shank 31 and a hexagon flange head 32.
(22) The base 10 comprises an L-shaped bracket, formed by bending a piece of steel plate, defining a top wall 12 and a side wall 14 projecting substantially perpendicular to the top wall 12. The top wall 12 defines apertures 13 for receiving fasteners, as will be described in further detail later. The side wall 14, likewise, defines apertures 15 for receiving fasteners, as will also be described in further detail later.
(23) Referring also to FIG. 2B, which shows the base 10 on its own, a hole 16 is formed through the upper wall 12 to enable receipt of the shank 31 through the wall 12, and the base 10 further comprises an internally threaded cylindrical boss 17 defined by an insert (shown on its own in FIG. 2C) that has been inserted through the hole 16 and plastically deformed so as to be swaged to the wall 12. The insert 200, shown schematically in undeformed and deformed conditions in FIGS. 2D and 2E respectively, comprises a generally cylindrical body 201 and an annular flange 203 arranged at an end of the body 201. The body 201 comprises a first portion 205, at one end of which the flange 203 is arranged, and a second portion 207, which extends from the other end of the portion 205 and defines internal thread 209. The second portion 207 diverges about a central longitudinal axis of the insert 200, in a direction away from the portion 205. The insert 200 is inserted into the hole 16 such that the flange 203 rests against the upper side of the wall 12. Thereafter, a compressive load is applied, in the direction of the longitudinal axis, to opposite ends of the insert 200, whereby shearing is effected at an annular interface 211 between the portions 205 and 207, such that the latter portion is displaced upwardly in the former portion, causing it to expand radially outwardly such that an underside of the wall 12 is engaged by the thus-expanded portion 205 and the upper side of the wall 12 is engaged by the flange 203, whereby there is a tight interlock between the insert 200 and the wall 12. Referring to FIG. 2B, the portion 205 is splined, promoting resistance of the boss 17 to rotation relative to the wall 12. A particularly suitable form of insert 200 is the Thin Sheet Nutsert™ 9658 series insert, shown in FIG. 2C, marketed by Avdel. The flange 203 is of relatively small thickness whereby its upper face is substantially flush with the upper surface of the wall 12.
(24) Referring to FIGS. 5A and 5B, fitting of the attachment 1 to the unit 100 involves positioning the base 10 such that the side wall 14 is received against strongback 130 and the top wall 12 is received against the underside of the truss 110. Fasteners, such as nails (particularly where the top chord 111/strongback 130 is timber), screws, or bolts, are then inserted or driven into apertures 13 and 15 to secure the walls 12 and 14 against the underside of the top chord 111 and an outer face of the strongback 130, respectively. Next, the anchor 30 is downwardly introduced shank-first into aligned holes 120A and 111A formed through the sheeting 120 and top chord 111 respectively, which holes align with the threaded bore of boss 17, and the anchor 30 is rotated such that the threads on the shank 31 engage with the internal thread of the boss 17, whereby the anchor 30 is screwed into the boss 17 and thus interconnected with the base 10, as shown in FIG. 5A. The hole 120A formed through the sheeting 120 is of a diameter slightly larger than the largest diameter of the head 32 (being the diameter of the annular flange of the head 32), whereby, when the anchor 30 is fully screwed down, the head 32 is countersunk in the sheeting 120, as shown in FIG. 5B. The hole formed through the top chord 111 is of a diameter smaller than that of the flange of the head 32 such that the latter abuts the top face of the chord 111 when the anchor 30 is fully screwed down. The thickness of the sheeting 120 is substantially equal to the depth of the head 32 such that the top surface of the head 32 is substantially flush with, or recessed with respect to, the exposed surface of the sheeting 120 when the anchor 30 is fully screwed down.
(25) The anchor 30 of the thus-installed attachment 1 is thus displaceable, relative to the base 10, between a position in which it is recessed with respect to the outer surface of the sheeting 120, and an exposed position, in which it projects beyond the outer surface such that the head 32 is engageable by a lifting clutch 300, as shown in FIG. 5C. Once the unit 100, as provided with the attachment(s) 1, has been lifted into position using the clutch(es) 300, and the/each clutch 300 has been disengaged, the head 32 can be rotated, by means of a tool, such as a socket wrench, such the anchor 30 either is screwed down, whereby to assume, its recessed or retracted position, or the anchor 30 can instead be unscrewed from the base 10 and thus released from the unit 100; either way, no part of the anchor 30 remains proud of the outer surface of the sheeting 120.
(26) FIG. 3 is a view of an alternative lifting component-anchor interconnection in accordance with an embodiment of the present disclosure (in which the base, sheeting, and trusses are not shown). The anchor 30 extends from the base through an opening in the sheeting, to project, proud of the sheeting, through a load ring 400, defining or forming part of a component for lifting the building unit, which load ring is thus retained between the head 32 and the sheeting 120. Once the building unit has been lifted via the load ring 400, the anchor 30 can be unscrewed from the base, whereby both it and the load ring 400 are released from the unit. In this arrangement, because the anchor 30 can be released from the base/unit, the sheeting and opening therein need not be dimensioned such that the anchor 30 can assume a position in which the top/outermost surface of the head 32 is substantially flush with, or recessed with respect to, the outer surface of the sheeting when the anchor 30 is fully screwed down.
(27) In the forthcoming description of further embodiments of the present disclosure, the same reference numerals as have been used in respect of the first embodiment will be used to denote and refer to the same or corresponding features in the further embodiments.
(28) Referring to FIGS. 6A to 6F, and attachment 1′ according to a second embodiment of the present disclosure and the application of that attachment to the unit 100, so as to render it liftable by lifting clutch 300, will now be described. Referring firstly to FIGS. 6C to 6E, the attachment 1′ includes a base 10 comprising an L-shaped bracket, formed by bending a piece of steel plate, defining a top wall 12 and a side wall 14 projecting substantially perpendicular to the top wall 12. The top wall 12 may, like that in the attachment 1, be configured with apertures (not shown) for receiving fasteners to secure it against the top chord 111. The side wall 14 like that in the attachment 1, defines apertures 15 for receiving fasteners to secure it against the strongback 130. As can best be seen in FIG. 6C, the base 10 in the present embodiment does not have a boss, and the hole 16 in the upper wall 12 is defined by a slot having a wide section 16A and a narrow section 16B. The anchor 30 of the attachment 1′, like that of the attachment 1, has a shank 31, which in the present embodiment is not threaded, and an enlarged head 32, which in the present embodiment is circular rather than generally hexagonal. The anchor 30 in the present embodiment further comprises a stopper 33 at a lower end of the shank 31. The stopper is sufficiently narrow that the anchor 30 can be lowered through hole 111A until the underside of the head 32 rests against the upper face of the top chord 111, at which point the head 32 is countersunk with respect to the exterior surface of the sheeting 120 and a lower end of the anchor 30 projects downwardly from the chord 111, as shown in FIG. 6C. The base 10, at this stage separate from the anchor 30, can then be raised whereby to effect insertion of the stopper 33 and shank 31 through the wide slot section 16A, such that the upper wall 12 is received against the underside of the top chord 111, as shown in FIG. 6D, and thereafter displaced laterally such that the shank extends through the narrow slot section 16B and the wall 14 is received against the strongback 130, as shown in FIG. 6E.
(29) Fasteners are then inserted through the apertures 15 in the side wall 14 to secure the side wall 14 against the strongback 130. Fasteners may also be inserted through apertures 13 in the top wall 12 to secure it against the underside of the top chord 111.
(30) The width of the narrow slot section 16E is smaller than the diameter of the stopper 33, whereby withdrawal of the anchor 30 from the base 10 in the thus installed attachment 1′ is precluded. In the attachment 1′, the anchor 30, instead of being rotatable in the base 10 as in the attachment 1, is slideable relative to the base 10 whereby to be displaceable axially between a recessed position, in which the head 32 is countersunk in the sheeting 120 and the exposed position, in which the head 32 is exposed outward of the outer face of the panel 120 whereby to be engageable by clutch 300 as shown in FIG. 4B. In the attachment 1′, the anchor 30 is gravitationally biased, whereby to assume its retracted position when the head 32 is uppermost. The anchor 30 can be displaced into its exposed position by engaging the underside of the head 32, e.g., with the claw of a claw hammer, as shown in FIG. 6F, for interconnection with the clutch 300. Without departure from the present disclosure, the attachment 1′ may, instead, include biasing means (not shown) such as a spring, which urges the anchor 30 towards its exposed position, which may be of sufficient strength to force the anchor 30 into that position irrespective of the orientation of the anchor 30.
(31) Referring now to FIGS. 7A to 7C, once the unit 100 has been lifted into position and the clutch 300 disengaged from the anchor 1′, a plug, in the form of a plastic cap 40, can be inserted into the opening 120A, thereby occluding that opening. The cap 40 is hollow and open at its lower end, whereby it accommodates the head 32 when inserted into the opening 120A and is configured such that an upper surface thereof lies substantially flush with the outer surface of the sheeting 120A. The cap 40 is resiliently deformable whereby it forms a press-fit in the opening 120A. Where the anchor is provided with the aforementioned biasing means, the press-fit is sufficient to overcome the force that biases the anchor 30 into its exposed position, whereby the inserted plug 40, and in particular the upper/outer surface thereof, holds the anchor 30 in a retracted position. If appropriate, an overlay 50 may thereafter be applied over the sheeting 120. It will be appreciated that the overlay 50 may, without departure from the present disclosure be so applied even if a plug 40 is not inserted into the/each opening 120A in the unit 100. Where the attachment includes the biasing means, it will then be the overlay 50 that forces the anchor into a retracted position against the bias.
(32) Shown schematically in FIGS. 8A and 8B, is an installed attachment 1″ in accordance with a third embodiment of the present disclosure, in which the anchor 30 is in its extended/exposed and recessed/retracted positions respectively. The attachment 1″ is substantially identical to the attachment 1′ except that the base 10 is configured with an L-shaped support member 60 comprising an upright portion 61 that extends downwardly from the chord-engaging upper wall 12, and a shelf portion that extends laterally from a lower end of the portion 61 so as to underlie the stopper 33 and thus engage the stopper 33 to preclude retraction of the anchor 30 beyond its recessed/retracted position, and the head 32 is smaller in depth, as is allowable given it need not bottom out against the upper surface of the top chord 111 to preclude excessive retraction of the anchor 30.
(33) Referring to FIG. 8C, a washer 64 can, without departure from the present disclosure, be positioned between the wall 12 and the underside of the chord 111 to increase the bearing area through which lifting loads are transferred into the sheeting 120. The wall 12 thus can engage the chord 111 either directly, as shown in FIGS. 8A and 8B, or indirectly, as shown in FIG. 8C. The washer is in certain embodiments 3 mm thick because typical sheeting thicknesses are 19 mm and 22 mm so that if attachment 1′ is dimensioned so as to be suitable for the latter thickness in the absence of washer 64, the employment of the washer 64 may render it suitable for the former thickness.
(34) It will be appreciated that a cap/plug can be used with the/each attachment 1 in generally the same manner as with the attachments 1′ and 1″, as may overlay 50.
(35) Shown schematically in FIG. 9 are details of an installed attachment 1″′ according to a fourth embodiment of the present disclosure. In the attachment 1″′, the anchor 30 is fixed relative to the base (not shown) and the head 32 remains countersunk within the opening 120A, which opening, in the case of this embodiment, may be larger and permit an appropriately configured lifting clutch 300′ to engage the countersunk head 32. Again, in the case of this embodiment, a plug/cap, as described above, may be used to occlude the or each opening 120A after the unit 100 has been lifted into position and the clutch 300′ disengaged from the respective anchor 1″′.
(36) Shown in the FIG. 10 are details of an anchor 1″″ according to a fifth embodiment of the present disclosure. The anchor 1″″ comprises a block 70, which may be molded from plastic (e.g., nylon) and is incorporated into the top cord 111; for example, the block 70 may be received in a gap 72 between sections 111A and 111B of the top chord 111 and secured to those sections by a nail plate (as shown) and/or other means. The anchor 1″″ is thus recessed with respect to the outer surface of the sheeting 120 (not shown). The anchor 1″″ comprises at least one slot 74 extending from a top side thereof to a bottom side thereof, and is configured with a pawl (not shown) formed into the block 70 and arranged in the or each slot 74. The anchor 1″″ thus assumes a form consistent with that of the open boss/case of a cable tie. In the case of this embodiment, the lifting component, instead of being a clutch, comprises a strip 400, which may be formed from plastic (e.g., nylon), the strip being configured with separate teeth 402 arranged axially therealong, whereby axial insertion of an end of the strip 400 through the slot 74 causes successive ones of the teeth to engage the pawl within that slot, in a manner permitting further insertion of the strip 400 but precluding withdrawal of it from the block 70 (as a result of the operation of the pawl). Where the block 70 defines only one slot 74, one end of the strip 400 is inserted through the opening 120A and thence into the slot 74 (that is aligned with that opening), so as to engage the block as just described, and the strip projects outward of the outer surface of the sheeting 120 so as to be exposed for connection of a suitable lifting element thereto for the purposes of lifting the unit 100. Where the block defines two spaced apart slots 74, respective, opposed, ends of the strip 400 can be inserted into those slots 74 (that will both be aligned with the opening 120A or will be aligned with respective the openings 120A) as shown in the final diagram in FIG. 10, whereby the strip 400 forms a loop 75, defining the lifting component, that projects beyond the outer surface of the sheeting 120 such that part of a lifting element can be received therethrough to be engaged therewith for the purposes of lifting the unit 100. Once the unit 100 has been lifted, the strip 400 can be cut or otherwise severed such that no part thereof projects outside the opening(s) 120A. Thereafter, the or each opening 120A can, if appropriate, be plugged in the manner previously described.
(37) The anchor 1″″ may, alternatively or additionally, be configured with a threaded hole 76 therethrough, the hole 76 being configured to interengage with a threaded anchor of any type previously described/illustrated, and thus essentially substituting for the base with which that threaded anchor interengages.
(38) Advantageous aspects of embodiments as described above and illustrated in the drawings include: in those embodiments in which the anchor assumes a retracted position, the unit thickness can be minimized for transportation purposes; the support structure of the building unit can comprise or be formed from any one or more of several materials including timber and steel; where the anchor is configured with a head, that head (be it, for example, an enlarged head or an eye), can be “standard” so as to be engageable with a standard, commonly available, lifting clutch, that may be able to be released/disengaged remotely from the anchor, possibly eliminating the need for a person to work at height to effect the release/disengagement; in the embodiment in which the attachment/base comprises a bracket, the part of the bracket that fixes to the unit can be skewed so that it is much more easily fixed in the factory as its fixing points would be far more accessible; and particularly where the unit is a floor cassette, calculation of the centroid of mass of the unit enables the attachments/anchors to be positioned such that the unit is stable for lifting yet such that they are under where internal walls will be placed, so that there is no need for any remedial work required on site to cover the lifting points, since they will be covered by the walls.
(39) While various embodiments of the present disclosure have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the present disclosure. Thus, the present disclosure should not be limited by any of the above described exemplary embodiments.
(40) Throughout this specification and the claims that follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.
