Screed rail

A boundary screed rail assembly with screed rails (14) supported by feet members (42). The screed rails (14) providing a perimeter part (24) with upper and lower protection parts (26). The upper part (26) provides a planar horizontal surface (28), with a plurality of recesses (30) extending thereinto, alternating with downwardly extending engagement members (32) engageable in the concrete of a slab.

This invention concerns improvements in or relating to boundary screed rails.

Boundary screed rails are used to define the perimeter of a volume in which a slab or other structure of a settable material is formed. Such slabs may typically be of concrete and form the floor of large structures such as for example warehouses, and will be cast in situ. The screed rails also provide the surface level of the slab, as well as providing edge protection therefor.

Where screed rails are provided on adjacent concrete floor slabs, it is important that the screed rails are at the same height, and protect the adjacent edges of the slabs to prevent breaking of or chipping thereof. The joint between the slabs must also be such as to permit contraction and expansion of the slabs, and also permit vertical loads to be received on the joints without damage to the slabs.

According to the present invention there is provided a boundary screed rail assembly, the assembly incorporating a screed rail which includes a generally planar perimeter part, and a plurality of feet members engageable with the ground to support the perimeter part on one side in a generally vertical alignment, the screed rail also includes a protection part extending along the in use upper edge of the perimeter part, the protection part including a planar upper surface extending in use generally horizontally from the perimeter member towards said one side, a plurality of spaced recesses extending into the edge of the planar surface away from the perimeter part, and a plurality of spaced engagement members extending in use generally downwardly from the said edge of the planar surface.

The engagement members and recesses are preferably alternately spaced along said edge of the planar surface, so as to define gaps between the engagement members, which gaps extend into the planar surface.

The engagement members may widen away from said edge. The sides of the engagement members may be rounded. The sides of the recesses may be rounded. The sides of the engagement members and recesses may lie substantially on a common circumference.

A protection part may also be provided along the in use lower edge of the perimeter part.

The perimeter and protection parts may be integrally formed.

The screed rail may be formed in discrete lengths which can be joined together as required. Adjacent lengths of screed rail may be mountable together by a respective feet member.

Mounting portions may be provided on the perimeter part to permit mounting of the feet members thereto. The mounting portions may be recessed towards said one side of the perimeter part such that fastening means for mounting the feet members to the perimeter part substantially do not extend beyond the other side of the perimeter part. Mounting formations may be provided in the mounting portions, which formations may be in the form of in use vertically extending slots.

The feet members may include a mounting part engageable with the mounting portions on the perimeter member, and a plurality of mounting holes may be provided on the mounting parts. The feet members may include a web part extending from the mounting part to a ground engaging part. The web part is preferably generally triangular, and a mounting hole may be provided therein. One or more mounting holes may be provided in the ground engaging part.

A plurality of openings may be provided in the perimeter part, and the openings may be configured to permit any of circular or square section, or plate dowels to extend therethrough.

The drawings show a boundary screed rail assembly10suitable for use in forming concrete slabs12as shown inFIG. 9. The assembly10comprises a screed rail14, and a plurality of feet members16mounted to the screed rail14at a number of locations by fasteners in the form of bolts18with heads20, and corresponding wing nuts22.

The rail14is elongate and can be provided in lengths and joined together and cut as required. The rail comprises a substantially planar perimeter part24alignable substantially vertically in use. Identical protection parts26are provided at the top and bottom of the perimeter part24.

The protection parts26provide a planar horizontal surface28. A plurality of spaced recesses30extend a short distance into the surface28on the opposite side thereof from the perimeter part24. Between each of the recesses30a downwardly extending engagement member32is provided. Each engagement member32widens away from the horizontal surface28, with arcuate side walls.

A plurality of openings34are provided along the length of the perimeter part24. The openings34are of a generally squat and wide T shape. The openings34permit circular or square section, or plate dowels to extend therethrough. Above each of the openings34a small circular opening35is provided. This permits adjacent rails14, as for instance shown inFIG. 7, to be held together for instance by plastics material fastenings, prior to pouring of the concrete.

A plurality of mounting portions36are provided along the screed rails14. The mounting portions36include a recess towards the side of the rails14on which the protection parts26are provided. Two lower and two upper vertical slots38are provided in the portions36. Similar mounting portions40are provided at the ends of the rails14, except that the end portions40only include one upper and one lower slot38.

The assembly10also comprises a plurality of feet members42. The feet members42include a mounting plate44engageable against the rear of the recessed mounting portions36, with four mounting holes46alignable with the respective slots38. A generally triangular web48extends perpendicularly from the mounting plate40to a footplate50. A mounting hole52is provided in the web48, as well as three larger holes53which provide a weight saving and help to anchor the members42in the concrete. Two small and two large holes54,56are provided in the footplates50.

In use, the feet members16are mounted in a required position. The members16may for instance be mounted on hardcore by spikes extending through one or more of the holes54,56. Where such an arrangement is not possible, the feet members16may be mounted by a portion of concrete58as shown inFIG. 3, which concrete58will extend through at least some of the holes53,54,56.

Alternatively, the feet members16may be mounted to pieces of wood60(FIG. 4) by a nail passing through the hole52, with the wood60being mounted in position elsewhere as possible. The screed rail or rails14are then mounted to respective feet members using the wing nuts22and bolts18, with the nuts22on the same side of the screed rails14as the feet members16. The height of the screed rails14can be set as required by virtue of the slots38.

The bolt heads20are accepted in the mounting portion recesses36.FIG. 7illustrates the positioning of two screed rails14to produce a joint between two slabs which will be adjacent each other. In view of the recessing of the bolt heads20, the two screed rails14can be located immediately adjacent each other. Appropriate dowels as required can be inserted through the openings34.FIG. 8illustrates how two screed rails14can be joined lengthways to each other by a single foot member16, which is mainly hidden behind the rails14, and is mounted to respective end mounting portions40on the rails.

Once the assembly or assemblies10are fully assembled, concrete can be poured into the space defined thereby to provide an arrangement as shown inFIG. 9. A levelling mechanism or straight edge can be run along the horizontal surfaces28to level the concrete12. The engagement members32provide for a good engagement between the screed rails14and the concrete12whilst not providing for a single linear joint which can readily lead to cracking. The widening of the engagement members32away from the horizontal surface provides a good anchorage thereof in the concrete12. The feature of the recesses30extending into the horizontal surfaces28, permits any potentially trapped air to be evacuated from within the protection parts26.

The assembly shown therefore permits strong edge protection to be provided, whilst reducing the possibility of damage occurring to the edge of the concrete. The assemblies permit ready adjustment of the height of the screed rails, and also adjacent assemblies to be located close to each other. The screed rails can readily be connected lengthwise to each other to provide a boundary of a required length. Different types of doweling can be provided to absorb vertical loads between adjacent slabs, and also to substantially prevent relative vertical movement between adjacent slabs.

Various modifications may be made without departing from the scope of the invention. For instance, in the illustrated assembly the screed rail is formed as an integral component by bending. Separate components could however be used in the screed rail. The shape of the recesses and/or engagement members could be different, and the recesses could be formed on the same circumference as the sides of the engagement members. Alternatively the engagement members may have a different shape, but which preferably also widens away from the horizontal surface.