AU2007203359B2

AU2007203359B2 - Temporary lintel apparatus

Info

Publication number: AU2007203359B2
Application number: AU2007203359A
Authority: AU
Inventors: Vincent Mcrobb
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-07-19
Filing date: 2007-07-19
Publication date: 2015-04-02
Anticipated expiration: 2027-07-19
Also published as: AU2007203359A1

Abstract

Temporary lintel apparatus (10) includes a lintel (11) having an upper surface (12) upon which blocks may be laid. At both ends (16) is spaced bails (17) welded to the side walls (20) and receiving support pins (22) which have an inner end (23) and a plane portion (21) of 8mm thickness, being symmetrically tapered at the part extending beyond the lintel body (11) in use. The pin (22) is made captive by means of withdrawal stops (24) which are welded in position after installation of the pin (22). In use the apparatus bridges a window or doorway space with pins (22) resting on top of the wall. Rows of blocks are laid over the apparatus. After at least partial curing, the inner end (23) is used to break the taper out of the bond and withdraw the pin (22) through its guide (17) to the stop (24), thus freeing the temporary lintel apparatus (10).

Description

1 TEMPORARY LINTEL APPARATUS FIELD OF THE INVENTION This invention relates to temporary lintel apparatus. 5 This invention has particular but not exclusive application to temporary lintel apparatus for use in the construction of block walls having window and/or door openings, and for illustrative purposes reference will be made to such application. However, it is to be understood that this invention could be used in other 10 applications, such as temporary lintel apparatus for brick construction with arch bars. PRIOR ART In block wall construction, the door and window apertures may be formed by 15 anyone of a number of ways. One way that is adapted from brick construction is to lay the head blocks defining the upper edge of the opening over an arch bar. However, since the block walls are generally grouted over rebars, the arch bar is redundant after the wall has set. 20 A further method lies in the use of a permanent or temporary structure defining the opening and over which the head blocks maybe laid. In one prior art embodiment typified by the disclosure of Australian Patent 608121, there is provided a temporary lintel comprising an inverted U-shaped section lintel portion of sufficient stiffness to support the head blocks and having end supports that temporarily 25 bridge the span of the prospective opening, the end supports being opposed plate like tongues which substantially lie in the plane of the top surface of the inverted U-shaped section and which may be retracted out of engagement with the wall to allow for removal after the wall is set. 30 The retraction means engage against an engagement means provided on each of the lower surfaces of the plate-like tongues. In order to retract the tongues a separate, lever-like tool is used to provide sufficient mechanical advantage to a user to break the bond which occurs between mortar and the tongues. The 2 tongues displace the mortar at the place of insertion. This tends to leave a significant overhang or cavity. The bond formed between the tongues and the mortar requires the use of considerable force, and may result in extraction of mortar lateral of the tongues. 5 In Australian Patent Appin. 2002301653, there is described a temporary lintel apparatus including an elongate lintel and an end support portion at each end of the elongate lintel and adapted to support the lintel, at least one of the end support portions comprising at least two spaced, substantially round section rod portions slidably supported on the lintel lintel and movable to an extended position to form 10 the end support member, and means for rotation and withdrawal of the rods from their extended position. The round section rods, being a solid of rotation, are easily broken out of the mortar by rotation about their long axes and, once broken out, may be withdrawn straight out. This round-pin arrangement is suitable for most sizes. However, over certain spans there may be stability issues. One 15 disadvantage of this construction is that the frictional engagement of the round bar with the mortar is considerable even when broken out by rotation. DESCRIPTION OF INVENTION This invention in one aspect resides broadly in temporary lintel apparatus including: 20 a lintel with an upper, substantially flat surface, and end supports supporting each end of the lintel in a wall whereby blocks or bricks may be laid there over, each said end support comprising at least two spaced support pins formed from flat bar and extending from the lintel, mounted for sliding withdrawal on the underside of the lintel in a space formed between the 25 underside of the lintel body and one or more transverse bails selected to allow each said pin to be worked from side to side to assist in initial break out, the pins being tapered in plan away from the lintel. The elongate lintel may be formed of roll formed section such as U-section channel steel. Alternatively, the elongate lintel may be fabricated. In either case 30 the upper substantially flat surface is preferably the upper surface of a relatively thin section, whereby the support pin may be slidably supported on the under surface or on the sides of the relatively thin section, such that the support pin is as 3 close to the plane of the upper surface as possible. To this end, and to provide for stiffness of the load supporting elongate lintel member the relatively thin section is stiffened by longitudinal webs. 5 One form of the elongate lintel member utilized C-channel purlin material. A fixed end support portion may take any suitable form. For example, such an end support portion may be formed of the native material of the elongate lintel such as by cutting away part of the optional C-channel purlin material. Alternatively such 10 an end support portion may be fabricated to the lintel portion. For example the end support portion may comprise one or more fixed members welded to the lintel portion. Preferably, any fixed end support portion comprises a pair of spaced rods welded to the lintel portion. The end support is preferably as close to the plane of the upper surface as possible. 15 The fixed support pins may be formed from mild or stainless steel round or flat bar, although it is envisaged that the round section rod portions may be formed of tube or other welded or drawn round section. 20 The movable support pins may be formed as a tapered spindle from round bar or the like, or may be formed from flat or rectangular bar tapered in one or both transverse planes. A round bar tapered spindle may be conically tapered. Alternatively the spindle may be tapered by forming opposed flats or longitudinally curved taper surface on round spindle stock. 25 The flat or rectangular bar taper may be straight or curved. If the taper is curved, the curve may form a concave or convex pin surface. Where the loads are greater, a biconvex pin may be preferred. Where the loads are lesser a biconcave pin may be preferred. In any case, flat bar pins are preferably tapered at least in 30 plan. In use a conically tapered pin tapers into air from a small contact point on the edge of the wall opening. In this embodiment, the single brick or block at each end may 4 be laid and allowed to set up before laying the rest of the course and subsequent courses over the lintel. Such a pin arrangement maximises the mortar section but is slower to lay. 5 Flat or solid rectangular bar support pins may be of any thickness up to the full thickness of the mortar joint. In most usages for brick or block, the pins may have a section of greater than 6mm, advantageously 8mm or greater. The movable pins may be mounted for sliding withdrawal on the underside of the 10 lintel. The movable pins may include a mounting portion of constant section adapted to slidably mount to a receiver portion of the lintel. The receiver portion for the movable support pins may take any suitable form. In the case of the preferred steel section lintel members, the receiver portion may comprise a formed or fabricated barrel, channel, slot or groove within which the support pins may 15 slide, and which retains the support pins against falling away from the lintel member. Alternatively, the pins may be mounted in a space formed between the underside of the lintel body and one or more a transverse bails, whereby the pin may be 20 worked from side to side to assist in breaking out. The ability to work the pins in this manner may also be used to work the mortar when laid, to enlarge the transverse clearance of the pins and thus reduce the mortar bond to the pins. This results in less effort to break out the pins when the mortar is cured. 25 The support pins may be captive in that they are constrained to slide only over the desired range of extension, or the support pins may be removable. Where the support pins are to be captive, there may be provided limit stop means against over-advancing the support pin. 30 Where conical or round-stock, tapered pins are used, these may be provided with a handle permitting operation in the manner of a rotating bolt, where the handle is rotated to effect initial break-out and then withdrawn to withdraw the conical pin portion from the mortar bed with eliminated contact and friction. Where round- 5 stock or flat or rectangular bar tapered pins are used, these may be provided with an extended butt enabling knocking outward with a hammer to effect initial break-out. The tapered portion may then be removed with much reduced friction when compared to plain section pins. 5 Where fixed end support is used, the lintel member may be foreshortened relative to the opening width to allow withdrawal of the temporary lintel. The choice of the actual number of the support pins may be made having regard to the width and length of the opening to be bridged, relative to the strength of the rod portions. In a further aspect this invention resides broadly in a method of forming an opening in a 0 wall being constructed of blocks or bricks and comprising the steps of: laying said blocks or bricks to define the sides of the opening; installing temporary lintel apparatus including a lintel with an upper, substantially flat surface, and respective end supports each comprising at least two spaced support pins formed from flat bar and extending from the lintel, mounted for sliding withdrawal 5 on the underside of the lintel in a space formed between the underside of the lintel body and one or more transverse bails selected to allow each said pin to be worked from side to side to assist in initial break out, the pins being tapered in plan away from the lintel; laying further blocks or bricks over the previous courses and temporary lintel apparatus to the extent and in a manner so as to provide a self supporting lintel when 0 set; allowing said wall to cure off; withdrawing said at least two spaced support pins from said extended position, and removing said temporary lintel apparatus from said wall. 25 In the case of brick walls, there may be interposed between the temporary lintel and the remaining courses an arch support, which may be of lesser section than an arch bar required to support the lintel course for curing of the lintel course. For example, the arch support may comprise a relatively thin perforated metal strip or the like whereby the mortars bond at each end of the strip is above and below the 30 6 strip and continuous through the perforations. Alternatively the arch support may comprise for example a pair of simple round bars laid over the temporary lintel before laying the remaining courses. In the case of concrete blocks and core bricks, rebars may be simply grouted in and cured off without the use of an arch 5 support. In order that this invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention and wherein: 10 FIG. 1 is a bottom perspective view of apparatus in accordance with the present invention; FIG. 2 is a top perspective view of the apparatus of FIG. 1, in use; FIG. 3 is a bottom detail view of the apparatus of FIG. 1; 15 FIG. 4 is a plan view of a support pin of the apparatus of FIG. 1; and FIG. 5 is a side view of the support pin of FIG. 4. In the figures, there is provided temporary lintel apparatus 10 including a lintel member 11 formed of C-channel purlin in galvanized steel. The lintel member 11 20 has an upper substantially flat surface 12 upon which blocks or bricks may be laid. At both ends 16 of the lintel member 11 there is provided a pair of spaced transverse bails 17 formed of flat bar steel section and welded to the opposed side walls 20 of the lintel member 11. 25 Each pair of bails 17 receives a pair of steel support pins 22 which have inner end portions 23 bent out of the plane to form an end stop and break-out tab. The bails 17 support the pin 22 in the space between the respective bail 17 and the underside of the substantially flat surface 12 portion of the lintel member 11. The 30 plane portion 21 is of constant vertical thickness of 8mm, with the horizontal section being symmetrically tapered at the portion remote from the lintel member 11 for a substantial part of the pin extending beyond the lintel body 11 in use. The support pin 22 is made captive by means of withdrawal stops 24 which are welded 7 in position after installation of the support pin 22, whereby the support pin 22 may only be withdrawn until the outer end 25 of the support pin 22 clears the extremity of the substantially flat surface 12 inward. 5 In use the temporary lintel apparatus 10 bridges a window or doorway space in a brick or block wall under construction. The support pins 22 rest on top of the wall at respective sides of the space. A row of blocks may then be laid over the top of the temporary lintel apparatus 10, over the upper substantially flat surface 12 so that the top of the space is closed. The wall is then cured in the conventional 10 manner with the grouting of rebars as required. In order to remove the temporary lintel apparatus 10 the inner end portions 23 are used to withdraw the support pins 22 thereby breaking the bond with the mortar by virtue of the taper breaking out. Each support pin 22 may then be withdrawn 15 through its guide 17 to the stop 24, whereby the lintel member 11 may be worked to remove the temporary lintel apparatus 10. It will of course be realised that while the above has been given by way of illustrative example of this invention, all such and other modifications and 20 variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as defined in the claims appended hereto.

Claims

1. Temporary lintel apparatus including: a lintel with an upper, substantially flat surface, and end supports supporting each end of the lintel in a wall whereby blocks or bricks may be laid there over, each said end support comprising at least two spaced support pins formed from flat bar and extending from the lintel, mounted for sliding withdrawal on the underside of the lintel in a space formed between the underside of the lintel body and one or more transverse bails selected to allow each said pin to be worked from side to side to assist in initial break out, the pins being tapered in plan away from the lintel.

2. Temporary lintel apparatus according to claim 1, wherein the taper is selected to form a biconvex pin where the loads are greater and a biconcave pin where the loads are lesser.

3. Temporary lintel apparatus according to claim 1, wherein the spaced support pins are captive.

4. Temporary lintel apparatus according to claim 1, wherein the spaced support pins are provided with an extended butt enabling knocking outward to effect said initial break-out.

5. A method of forming an opening in a wall being constructed of blocks or bricks and comprising the steps of: laying said blocks or bricks to define the sides of the opening; installing temporary lintel apparatus including a lintel with an upper, substantially flat surface, and respective end supports each comprising at least two spaced support pins formed from flat bar and extending from the lintel, mounted for sliding withdrawal on the underside of the lintel in a space formed between the underside of the lintel body and one or more transverse bails selected to allow each said pin to be worked from side to side to assist in initial break out, the pins being tapered in plan away from the lintel; laying further blocks or bricks over the previous courses and temporary lintel apparatus to the extent and in a manner so as to provide a self supporting lintel when 9 set; allowing said wall to cure off; breaking out and withdrawing said at least two spaced support pins from said extended position, and removing said temporary lintel apparatus from said wall.

6. A method according to claim 5, wherein an arch support is interposed between said temporary lintel and laying of said blocks or bricks.

7. A method according to claim 6, wherein said arch support comprises a relatively thin perforated metal strip or the like whereby the mortar bond at each end of the strip is above and below the strip and continuous through the perforations.

8. A method according to claim 5, wherein said wall is of hollow core blocks and wherein rebars are grouted into said further blocks and cured off without the use of an arch support.

9. Temporary lintel apparatus substantially as hereinbefore defined with reference to the accompanying drawings.