IES20010853A2 - Hollow-core floor slabs - Google Patents

Abstract

A hollow-core floor slab (1) has an elongate reinforced concrete body (2) of generally trapezoidal section with cylindrical channels(11) extending between opposite ends (5) of the body (2). A plurality of spaced-apart dove-tail key slots (10) are proivided along each side (6,7) of the body (2) to facilitate locking adjacent slabs (1) together in use. A process for manufacturing the slabs (1) includes inserting core pipes into an upwardly open mould, filling the mould with concrete and then hinging the mould about one side of the mould into an inverted position to engage a drying pallet. After extraction of the core pipes from the mould the drying pallet is dropped downwardly to release the slab (1) from the mould. The slab (1) is delivered on the drying pallet to a drying station and the mould is swung back on its hinges into the upwardly open filling position to form the next slab (1). <Figure 1>

Description

“Hollow-core floor slabs “ IEO I 08 5 J This invention relates to hollow-core floor slabs and to a process for their production.

According to the invention there is provided a hollow-core floor slab including a reinforced concrete body of generally trapezoidal cross section having a top face, io a bottom face, side faces extending between the top and bottom faces and end faces extending between the top and bottom faces, each side face having a plurality of spaced-apart key slots therein extending downwardly from the top face and terminating above the bottom face, each key slot being tapered such that it narrows inwardly as the slot extends downwardly from the top face, and each slot being of dovetail section having angled side faces extending inwardly from a mouth of the slot towards a back face of the slot.

According to another aspect of the invention there is provided a process for the manufacture of hollow-core floor slabs including the steps: coating an inside face of an open-topped slab forming mould with a release agent, the mould having a slab forming trough with a base, upwardly extending side walls at each side of the base, and upwardly extending end walls at each end of the base extending between the side walls, said mould being positioned in an upwardly open filling position. inserting a number of spaced-apart substantially parallel core pipes into the mould intermediate the base and a top of the mould and extending between opposite ends of the mould, said core pipes being inserted through associated openings in one end wall of the mould and extended for engaging with complimentary slots in mould, coating the core pipes with a release agent, the opposite end wall of the OPEN TO PUBLIC INSFECnCN UNDER SECTION 28 AND RULE 23 JNL OF ^ΐ)οξ |^Ρο22 delivering a first batch of concrete into the mould, partially filling the mould with the concrete and evenly distributing the concrete along the base of the mould, vibrating the mould for settling the concrete within the mould and levelling the concrete in the mould, mounting a steel reinforcing element within the mould above the core pipes, delivering a second batch of concrete into the mould, covering the steel reinforcing element and filling the mould, vibrating the mould for settling the concrete within the mould, smoothing and levelling a top surface of the concrete within the mould with an upper rim of the mould, locating a drying pallet alongside the mould, hinging the mould about one side of the mould which is attached to a pivot shaft, rotating the mould and pivot shaft for inverting the mould and engaging the rim of the mould and an exposed concrete face of the slab within the mould with the drying pallet when the mould is in the inverted position, removing the core pipes from the mould by extracting the core pipes through an end wall of the mould, dropping the pallet downwardly away from the mould releasing the cast slab from the mould and carrying the slab away from the mould, rotating the mould and pivot shaft for returning the mould to the upwardly open filling position, delivering the pallet carrying the cast hollow-core floor slab to a drying station for curing the concrete.

In one embodiment of the invention the process includes the steps: mounting a drying pallet on a conveyor which runs substantially perpendicularly relative to the mould, delivering the pallet on the conveyor to a loading station alongside and substantially parallel to the mould, at the loading station engaging lifting means with the pallet for lifting the pallet clear of the conveyor, raising the pallet to a loading position at which a top surface of the pallet is located to receive and engage the rim of the mould and the exposed concrete surface of the cast slab within the mould when the mould is rotated into the inverted position, after retracting the core pipes from the mould lowering the pallet by means of the lifting means onto the conveyor releasing the slab from the mould and delivering the pallet away from the mould on the conveyor.

In another embodiment the core pipes are mounted on a carriage at one end of the mould, said carriage being moveable between a retracted position supporting the core pipes externally of the mould and an extended position for advancing the core pipes through the end wall openings into the mould, the carriage having an upstanding core pipe holder with a number of spaced-apart upwardly open core pipe engagement slots associated with the core pipes one of which engages with each of the slots, an engagement head being provided at an outer end of each core pipe for ΙΕΟ IOS engagement with a complementary engagement slot in the core pipe holder, the engagement head comprising an arm projecting axially outwardly at the outer end of the core pipe and terminating in a flanged end, the arm engaging in the slot with an end of the core pipe at one side of the core pipe holder and the flanged end at the opposite side of the core pipe holder, the carriage being moveable along a support bed between the retracted position and the extended position, the support bed being slideable transversely relative to the mould for aligning the carriage and the mould when the mould is in either the upwardly open loading position or the inverted unloading position.

In a further embodiment the mould has a plurality of spaced-apart pivot arms projecting outwardly from one side of the mould, each pivot arm being attached to a pivot shaft which is rotatably supported between a number of journal bearings on ground-engaging bearing posts, drive means being provided for rotating the pivot shaft for moving the mould between the upwardly open loading position and the inverted unloading position.

In another embodiment each drying pallet has a flat top slab-receiving panel with a downwardly depending skirt extending downwardly about a periphery of the top panel defining a hollow downwardly open internal chamber, and at the drying station a number of pallets are stacked one above the other with a hollow-core floor slab on a first pallet being housed within the internal chamber of a second pallet which is mounted directly above and resting on said first pallet.

Conveniently the mould is adapted for simultaneously casting two or more slabs, at least one internal divider wall being mounted intermediate the ends of the mould extending between the side walls and having through holes for through passage of the core pipes. in another embodiment a concrete delivery hopper is mounted on an overhead carriage which is moveable between opposite ends of the mould above the mould when the mould is in the loading position, drive means and associated control means being operable to move the hopper between opposite ends of the mould whilst discharging concrete from the hopper into the mould in a controlled manner.

In a further embodiment downstream of the drying station cured hollow-core floor slabs are removed from the pallets by mounting each pallet on an unloading platform, engaging one side of the hollow-core floor slab with a pusher arm and pushing the hollow-core floor slab laterally off the pallet onto a discharge conveyor for delivery to a storage unit.

The invention will be more clearly understood by the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which; Fig. 1 is a perspective view of a hollow-core floor slab according to the invention; Fig. 1 is a side elevational view of the hollow-core floor slab; Fig. 3 is an end elevational view of the hollow-core floor slab; Fig. 4 is a plan view of the hollow-core floor slab; Fig. 5 is an elevational view illustrating apparatus for manufacture of the hollow-core floor slab; Fig. 6 is an end elevation view of the apparatus; Fig. 7 is a plan view of the apparatus; Fig. 8 is an elevational view of another portion of the apparatus; Fig. 9 is a detail perspective view of a core pipe used in the process in engagement with an associated carriage; and Fig. 10 is a side elevational view of the core pipe and carriage portion shown in fig. 9.

Referring to the drawings, and initially to figs. 1-4 thereof, there is illustrated a hollow-core floor slab according to the invention indicated generally by the reference numeral 1. The hollow-core floor slab 1 has an elongate reinforced concrete body 2 of generally trapezoidal cross-section with a generally rectangular top face 3 and rectangular bottom face 4. Substantially vertical end faces 5 extend between the top face 3 and bottom face 4. Downwardly sloping side faces 6, 7 also extend between the top face 3 and bottom face 4. Each side face 6, 7 has an outwardly protruding lip 8, 9 extending along a bottom edge of the side face 6, 7. In each side face 6, 7 there are provided a plurality of spaced-apart key slots 10. A number of spaced-apart substantially parallel cylindrical channels 11 extend through the body 2 between opposite ends 5 of the body 2.

It will be noted that the key slots 10 are upwardly open at the top face 3 and taper inwardly as they extend downwardly towards the bottom 4, terminating just above the lip 8, 9. It will further be noted that each slot 10 has a dovetail configuration.

In use, a number of the hollow-core slabs 1 are mounted edge to edge on a support to form a floor base which is covered in a flooring compound which fills between adjacent slab 1 sides and into the slots 10 thus keying the slabs 1 together resisting any movement apart of the slabs 1.

Referring now to figs. 5 to 10, a process and apparatus for manufacturing the hollow-core slabs 1 will be described.

An open-topped mould 20 has a generally rectangular elongate shape with an interior of the mould 20 corresponding to the exterior shape of the body 2 of the hollow-core slab 1. The mould 20 has a slab forming trough with a base, upwardly extending side walls at each side of the base, and upwardly extending end walls at each end of the base extending between the side walls. A number of projections extend along opposite side walls of the mould 20 corresponding to the dovetail key slots 10.

Mounted adjacent one end of the mould 20 a plurality of juxtaposed core pipes 22 are mounted on a carriage 23 which is siideably mounted on a support bed 24. At a front end of the support bed 24 the core pipes 22 rest on and are supported by a roller 25. Means (not shown) is provided for advancing the carriage 23 and hence the core pipes 22 in a longitudinal direction towards the mould 20 for insertion through complementary openings in an end wall of the mould 20 to insert the core pipes 22 into the mould 20. It will be noted that the support bed 24 is slideable transversely relative to the core pipes 22 along rails 26 as indicated by arrow X in Fig. 7 between mould loading and unloading positions.

A number of pivot arms 30 project outwardly at an inner side of the mould 20 and are attached to a pivot shaft 31. Means (not shown) is provided for pivoting the pivot shaft 31 and hence the mould 20 through 180° for inversion of the mould 20 to discharge a cast slab 1 onto a drying pallet 35 positioned alongside the mould 20.

To position the drying pallet 35 alongside the mould 20 the pallet 35 is delivered onto a conveyor 40 which runs substantially perpendicular relative to the mould 20. The pallet 35 is delivered on the conveyor 40 to a loading station alongside and substantially parallel to the mould 20. At the loading station a pair of scissors lifts (not shown) beneath the conveyor 40 are operable for raising the pallet 35 above the conveyor to a loading position at which a top surface of the pallet 35 is located to receive and engage a rim of the mould 20 and the exposed concrete surface of the cast slab within the mould 20 when the mould 20 is rotated by the pivot shaft 31 into the inverted position.

To manufacture a slab 1 the mould 20 interior is first sprayed with an oil release coating. The core pipes 22 are then advanced by the carriage 23 on the support bed 24 through the associated openings in the end of the mould 20 and through the mould 20 to extend fully through the mould 20. A further spray of release agent is injected into the mould 20 coating the core pipes 22.

An overhead concrete delivery hopper 50 is operable to traverse the mould 20 longitudinally discharging an initial deposit of concrete into the mould 20. Some light handling steel bars are inserted into the mould 20 and the mould 20 is vibrated to settle the concrete within the mould 20.

Next a steel reinforcing element is mounted in the mould and the concrete hopper 50 is again delivered over the mould 20 to discharge a further batch of concrete into the mould 20 covering the reinforcing element and filling the mould 20 to the required depth of concrete. The mould 20 is then vibrated to settle the concrete and a top surface of the concrete can be smoothed or otherwise treated as required and is levelled with a rim of the mould 20.

A drying pallet 35 is positioned alongside the mould 20. The mould 20 is then pivoted on the pivot shaft 31 to position the cast slab 1 above and engaging the pallet 35. Next the core pipes 22 are retracted from the mould 20.

After removal of the core pipes 22 the pallet 35 is lowered on the scissors lift downwardly away from the mould 20 until the pallet 35 rests on the conveyor 40. Dropping the pallet 35 downwardly away from the mould 20 releases the cast slab 1 from the mould 20 carrying the cast slab 1 away from the mould 20. Once the cast slab 1 is clear of the mould 20 the mould 20 can be rotated with the pivot shaft 31 back to the original filling position.

The conveyor 40 delivers the pallet 35 away from the mould 20 and an overhead grab engages and picks up the pallet 35 and deposits the pallet 35 in one of a number of stacks 45 for curing and setting the slab 1.

Downstream of the drying stacks 45, when the slabs 1 have fully set they are removed from the pallets 40 by means of a pusher arm 60 which is moveable along a slide 61 to push a slab 1 onto a conveyor 63 for delivery to a storage unit 64 at which the slabs 1 can be stored in a number of stacks one above the other awaiting distribution.

Referring now to figs. 9 and 10. The arrangement for mounting the core pipes 22 on the carriage 23 is shown. The carriage 23 has at its front end an upstanding core pipe holder plate 27. A number of spaced-apart upwardly open core pipe engagement slots 28 are provided in the holder plate 27 extending downwardly from a top edge of the holder plate 27. It will be noted that these slots 28 are Vshaped to allow for pivoting disengagement of the core pipes 22 from the slots 28 when the mould 20 is being pivoted with the pivot shaft 31. An engagement head 29 at an outer end of each core pipe 22 is engagable with the slot 28. The engagement head 29 comprises an arm 36 projecting axially outwardly at an outer end of the core pipe 22 and terminating in a flanged end 37. As can be seen in fig. 9 the arm 36 engages in the slot 28 with an end 38 of the core pipe 22 at one side of the core pipe holder plate 27 and the flanged end 37 at the opposite side of the core pipe holder plate 27. This allows the carnage 23 to push the core pipes 22 into the mould 20 or retract the core pipes 22 from the mould 20. Further, it will be noted that the open topped slots 28 allow the core pipes 22 to be pivoted with the mould 20 from the filling position into the inverted slab discharging position. During pivoting once the core pipes 22 are lifted clear of the core pipe holder plate 27 the support bed 24 is moved transversely on the rails 26 for alignment of the core pipe holder plate 27 with the mould discharge position. Thus when the mould 20 moves into the discharge position the core pipes 22 will again engage with the core pipe holder plate 27 which can subsequently be retracted with the carriage 23 on the support bed 24 for removal of the core pipes 22 from the mould 20.

The invention is not limited to the embodiments hereinbefore described which may be varied in both construction and detail within the scope of the appended claims.

Claims (3)

1. A hollow-core floor slab, including a reinforced concrete body of generally trapezoidal cross-section having a top face, a bottom face, side faces extending between the top face and the bottom face and end faces extending between the top face and the bottom face, each side face having a plurality of spaced-apart key slots therein extending downwardly form the top face and terminating above the bottom face, each key slot being tapered such that it narrows inwardly as the slot extends downwardly from the top face, and each slot being of dovetail section having angled side faces extending inwardly from a mouth of the slot towards a back face of the slot.

2. A hollow-core floor slab substantially as hereinbefore described with reference to the accompanying drawings.

3. A process for the manufacture of hollow-core floor slabs, including the steps: coating an inside face of an open-topped slab forming mould with a release agent, the mould having a slab forming trough with a base, upwardly extending side walls at each side of the base, and upwardly extending end walls at each end of the base extending between the side walls, said mould being positioned in an upwardly open filling position, inserting a number of spaced-apart substantially parallel core pipes into the mould intermediate the base and a top of the mould and extending between opposite ends of the mould, said core pipes being inserted through associated openings in one end wall of the mould and extending for engaging with complementary slots in the opposite end wall of the mould, coating the core pipes with a release agent, IE 0 1 0 8 5 3 - 11 delivering a first batch of concrete into the mould, partially filling the mould with the concrete and evenly distributing the concrete along the base of the mould, vibrating the mould for settling the concrete within the mould and levelling the concrete in the mould, mounting a steel reinforcing element within the mould above the core pipes, delivering a second batch of concrete into the mould, covering the steel reinforcing element and filling the mould, vibrating the mould for settling the concrete within the mould, smoothing and levelling a top surface of the concrete within the mould with an upper rim of the mould, locating a drying pallet alongside the mould, hinging the mould about one side of the mould which is attached to a pivot shaft, rotating the mould and pivot shaft for inverting the mould and engaging the rim of the mould and the exposed concrete face of the slab within the mould with the drying pallet when the mould is in the inverted position, removing the core pipes from the mould by extracting the core pipes through an end wall of the mould, dropping the pallet downwardly away from the mould releasing the cast slab from the mould and carrying the cast slab away from the mould, rotating the mould and pivot shaft for returning the mould to the upwardly open filling position, IE 0 J fl 8 5 J - 12 delivering the pallet carrying the cast hollow-core floor slab to a drying station for curing the concrete. A process for manufacturing hollow-core floor slabs substantially as hereinbefore described with reference to the accompanying drawings. A hollow-core floor slab whenever produced by the process as claimed in claim 3 or claim 4.