GB2258483A - Device for facilitating the laying of paving stones - Google Patents

Abstract

The device comprises a reference portion defined by an extruded tube 410 having a slot 411 cut into one end. A grading portion formed by a plate 412 is mounted in the slot 411 using screws 414 with wing nuts, the screws 414 engaging in vertical slots in the plate 41250 that the vertical position of the plate 412 relative to the tube 410 can be set and clamped. The lower surface of the tube 410 acts as a reference portion which is engaged with the upper surface of a paving stone which has already been laid, and is drawn across the laid paving stone so that the lower, ground-engaging edge of plate 412 scrapes previously laid particulate support material from the ground to the desired depth, whereby to enable a further paving stone to be laid with its upper surface in accurate alignment with the upper surface of the previously-laid paving stone and with the particulate support material in total surface contact with the underside of said further paving stone. <IMAGE>

Description

DEVICE FOR FACILITATING THE LAYING OF FLAGS This invention relates to a device for facilitating the laying of paving flags, slabs, blocks, bricks or the like (hereinafter simply referred to as "flags"), and also to the use of such a device.

When laying paving flags or slabs, it is commonly the practice to lay each flag on a group of usually five spaced mounds of sand and cement mixture and then to tap the flag until it is at the correct level. After the sand/cement mix has set, the flag is stabilized at least to some extent. If the piles of sand/cement are correctly positioned and contain the correct quantity, then theoretically the flag is supported by set sand and cement material which extends evenly over the whole of the area of each flag. However, in practice, it is common for there to be insufficient sand and cement mix to perform this function and for the flag to remain supported by separate pads of sand and cement material.

Under heavy rain or flooding conditions, some of the underlying support material can be washed away and this leads to the flags sinking in time.

An object of the present invention is to obviate or mitigate the above disadvantage by providing a device which facilitates the laying of flags on a completely flat base.

According to the present invention, there is provided a device for facilitating the laying of flags, said device comprising a reference portion which is adapted to engage the upper surface of a flag which has already been laid, and a grading portion joined to the reference portion and having a ground-engaging edge which is set or adapted to be set at a desired level below the upper surface of said flag, whereby, in use, the reference portion can be drawn across the laid flag so that the ground-engaging edge of the grading portion scrapes previously laid particulate support material (eg a sand/cement mixture) from the ground to the desired depth, and a further flag can be laid with its upper surface in accurate alignment with the upper surface of the first-mentioned flag with the support material in total surface contact with the underside of said further flag.

With such an arrangement, it is possible to lay flags easily and quickly once the first flag has been laid and set in the desired position, whether this be completely level or with a slight fall if necessary to permit drainage in a particular direction.

The present invention also resides in the use of a device according to the present invention as defined above in the laying of flags, and in a method of laying flags wherein a first flag is laid at the desired level, particulate support material is distributed adjacent to the laid flag (and tamped down if desired) in an amount which is not less than that required to support the next flag at the desired level, the reference portion of the device is then brought into contact with the upper surface of the set slab and drawn across said surface so as to urge the grading portion over the distributed support material whereby a substantially planar support surface is formed, and another flag is laid on said substantially planar support surface.

In a preferred embodiment, the ground-engaging edge is adjustable relative to the planar reference portion so that the desired depth of scrape can be adjusted. If desired, adjusting screw means or the like may be provided and arranged upon rotation to lift or lower the grading portion relative to the reference portion for grading depth setting purposes. In one embodiment, the reference portion is defined by a handle having a longitudinal slot therein to receive a plate which defines the grading portion, the plate being vertically adjustable relative to the handle, and means being provided for fixing the plate relative to the handle.In such an embodiment, plate may be laterally extended to engage in the slot in the handle so that the lateral extension of the plate overlies the reference slab in use, or the handle may be laterally extended so that the slot overlies the ground to be graded in use.

Instead of providing a slot in the handle, the handle and plate may be secured together in mutual sid-by-side abutment.

The ground-engaging edge may be defined by a flat or planar blade, or it may have small serrations thereon to produce a series of ridges and troughs in the support material which are of a size and shape such that the material forming the ridges is caused to fill the troughs under the weight of the flag being laid thereon.

If desired, the device may be provided at any convenient location with a level indicating device such as a bubble level to facilitate use.

If desired, the device may include a handle to facilitate pressing of the reference portion of the device against the upper surface of a set flag. Such reference portion may be provided by rolling means, eg wheels or a roller, to facilitate movement of the device relative to a set flag. The handle itself may include a configurated plate which projects from the handle and which can be used for inserting between flags and lifting them by a pivoting action.

When using the device for smaller blocks or bricks as opposed to relatively large flags, it will usually be necessary to set a number of such bricks or blocks over a sufficiently large area to provide an adequate surface for contact by the reference portion of the device. Once these blocks or bricks have been set at the required level, then the device can be used for scraping an area of the particulate material down to the required level, followed by laying of a plurality of such bricks or blocks over the scraped area.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a side view showing how a relatively simple device according to the present invention can be used to facilitate laying of flags, Fig. 2 is a schematic view in the direction of arrow A in Fig. 1, Fig. 3 is a side view of another form of device according to the present invention, and Fig. 4 is an end view in the direction of arrow B in Fig. 3, Fig. 5 is a schematic view showing various parts of a further form of device according to the present invention, Fig. 6 is a schematic perspective view showing a detailed modification, Fig. 7 is a perspective view of a further embodiment, Fig. 8 is a cross-section through part of the device of Fig. 7, Fig. 9 is a perspective view of a modification of the device of Figs. 7 and 8, and Figs. 10a to 10c are perspective views of a further modification of the device of Figs. 7 and 8.

Referring now to Figs 1 and 2 of the drawings, the device illustrated therein simply comprises a length of timber 10 which, in this embodiment, is of four inch by two inch section and is about four feet long. A two foot long metal plate 12 providing a grading portion of the device is secured by screws 14 to a longitudinal side edge of the timber 10 so as to project downwardly (as viewed in Figs. 1 and 2) below the timber 10 by a distance which corresponds to the thickness of flags to be laid. In Figs. 1 and 2, a datum flag 16 of the same depth as those to be laid after use of the device is illustrated.

In use, datum flag 16 is laid carefully on a prepared surface so that the upper surface of the datum flag 16 is set correctly at the desired level and with the correct degree of fall for drainage if this is desired. Once the datum flag 16 has been set correctly, a sand/cement mixture 18 is distributed over the area of ground next to the datum flag 16 where the next flag is to be laid. The sand and cement mixture is tamped down to provide the required amount of consolidation, a sufficient amount of sand and cement mixture being employed so that the level after tamping is rather higher than that required. The device is then positioned so that the timber is engaged with the upper surface of the datum flag 16 so that the plate 12 extends over the sand and cement mixture which has been laid.The timber 10 is then drawn across the upper surface of the datum flag 16 carefully so that the plate 12 scrapes excess sand and cement mixture away down to the desired level. The sand and cement material is thereby scraped down to exactly the required level using the datum flag 16 as a guide.

The next flag can then be laid directly on the scraped surface of the sand and cement material with the result that its upper surface is accurately aligned with that of the datam flag 16 and rests against the sand and cement mixture over the whole of its underside. Another flag can then be laid either next to another edge of the datum flag 16 in which case the datum flag 16 is again used to set the desired level. Alternatively, the next flag can be laid next to the previously laid flag in which case the latter is used as a new datum flag over whose upper surface the timber 10 is drawn to effect the next scraping operation.From the above, it will be appreciated that the lower surface 20 of that portion of the timber 10 which engages the datum flag 16 in use provides a reference portion which simply and effectively enables the next flag to be set accurately at the desired level relative to an adjacent flag which has already been laid.

The device illustrated in Figs. 3 and 4 operates in a similar manner. In this embodiment, the device comprises a square or rectangular section tube 110 instead of timber 10. Plate 112 is slotted at 113 so that it can be adjustably mounted on the tube 110 using screws 114 so that the desired depth of scrape can be set. The tube 110 supports a roller 118 which engages against the upper surface of a laid flag 116 and thereby provides the reference portion of the device. A detachable handle 122 secured to the tube 110 facilitates use of the device without having to bend down. The handle 122 is provided over that region of the tube 110 which overlies the roller 118. The handle 120 is detachably secured to the tube 110 by means of thumb screws 124.

In the embodiment of Fig. 5, instead of being supported under part of tube 210, roller 220 is mounted via bearings (not shown) over a circular section bar 125 extending laterally from the tube 210. Tube 210 has a flattened section 126 against which adjustable slotted plate 212 is urged by fixing screws (not shown). The device of Fig. 5 is fitted with a handle (not shown) which engages over the bar 125 and at either end of the roller 220.

Fig. 6 shows part of a handle 322 of the device fitted with a rigid configurated plate 326 which is designed to fit between adjacent laid flags and to facilitate lifting thereof for re-laying purposes.

In the embodiment of Figs 7 and 8, a length of extruded anodised aluminium alloy tube 410 has a slot 411 cut into one end. The slot 411 has a width such as to receive metal plate 412 as a close sliding fit therein.

The metal plate 412 has a pair of spaced elongate vertical slots (not shown) therethrough. Screws 414 with wing nuts engage in these slots and adjustably mount the plate 412 in the slot 411 for vertical sliding movement and clamping. Push-on end caps 415 serve to close the otherwise open ends of the tube 410. The tube 410 is extruded with opposed pairs of vertically staggered axially extending internal ribs 430 and 432. Each of the ribs 430 and 432 extends inwardly of the tube 410 to a position which is spaced from the vertical median plane of the tube 410 by just over half of the thickness of the plate 412.The ribs 430 and 432 thereby act as lateral supports for the plate 412, particularly when the latter is in a position in which its upper edge is disposed within the tube 410 and is therefore laterally unsupported by the edges of that part of the slot 411 which is formed in the upper surface of the tube 410.

The tube 410 has opposed longitudinal recesses 434 to facilitate gripping, and a planar undersurface to act as the reference portion. The lower edge of the plate 412 acts as the ground-engaging portion of the device.

In Fig. 9, the tube 410 of Figs. 7 and 8 is extruded without the ribs 430 and 432 and is provided with an internal plate clamp-and-guide arrangement which, in this embodiment, comprises a pair of plastics mouldings 438 inserted into the tube 410. Each moulding 438 comprises a longitudinal bar 440 extending integrally from one side of a head 442 which is a close fit in a respective side of the slotted end of the tube 410. Each bar 440 is moulded integrally with a pair of spaced apertured lugs 444 through which a respective one of the screws 414 passes. Each lug 444 has upper and lower resilient lips 446. The mouldings 438 are spaced apart and are located on respective sides of the plate 412 so as to maintain it in position.Tightening of the screws 414 serves to clamp the plate 412 between the mouldings 438 and also to press the lips 446 of the lugs 444 against the adjacent inner wall of the tube 410 so that the plate 412 is held firmly in the tube 410 against sliding movement relative thereto.

In Figs. 10a and 10b, the tube 410 is extruded with a part-spherical undercut longitudinal groove 450 in its upper edge to receive a cylindrical bubble spirit level 452 which is inserted into one end of the groove 450, slid into a convenient location along the groove 459, and then adhesively secured in place. The slot 411 is cut in the base of the groove 450 so that if there are any sharp edges resulting from cutting of the slot 411, these are located in the base of the groove 450 and are unlikely to cause injury to the operator. The tube 410 is also extruded with a single strengthening rib 454 which is slotted at one end (Fig. lOb) to receive the plate 412.

In Fig lOc, the tube 410 has a complete slot 455 running fully along its bottom edge to receive one or more plastics wear pads 456 which can be located as desired along the tube 410 at locations where it is to be brought into engagement with the upper surface of a slab in use.

The wear pads 456 are shown in this embodiment as having lateral grooves into which the edges of the slot 455 engage. However, in an alternative embodiment (not shown), this slot 455 may be dispensed with and the wear pads 456 may be formed with curved arms which embrace the curved lower edges 458 of the tube 410.

The arrangement of Figs. 10a and lOb and of Fig. lOc may be used in conjunction with the mouldings 438 of Fig. 9.

Claims (7)

1. A device for facilitating the laying of flags, said device comprising a reference portion which is adapted to engage the upper surface of a flag which has already been laid, and a grading portion joined to the reference portion and having a ground-engaging edge which is set or adapted to be set at a desired level below the upper surface of said flag, whereby, in use, the reference portion can be drawn across the laid flag so that the ground-engaging edge of the grading portion scrapes previously laid particulate support material from the ground to the desired depth, and a further flag can be laid with its upper surface in accurate alignment with the upper surface of the first-mentioned flag with the support material in total surface contact with the underside of said further flag.

2. A device as claimed in claim 1, wherein the ground-engaging edge is adjustable relative to the planar reference portion so that the desired depth of scrape can be adjusted.

3. A device as claimed in claim 2, wherein the reference portion is defined by a handle having a longitudinal slot therein to receive a plate which defines the grading portion, the plate being vertically adjustable relative to the handle, and means being provided for fixing the plate relative to the handle.

4. A device as claimed in claim 3, wherein the handle comprises a tube having the longitudinal slot therein, and ribs are provided internally of the tube to act as lateral support for the plate.

5. A device as claimed in claim 1, substantially as hereinbefore described with reference to Figs 1 and 2, or Figs 3 and 4, or Fig 5, or Fig 6, or Figs 7 and 8 of the accompanying drawings.

6. The use of a device as defined in any preceding claim in the laying of flags.

7. A method of laying flags using a device as claimed in any one of claims 1 to 5, wherein a first flag is laid at the desired level, particulate support material is distributed adjacent to the laid flag in an amount which is not less than that required to support the next flag at the desired level, the reference portion of the device is then brought into contact with the upper surface of the set slab and drawn across said surface so as to urge the grading portion over the distributed support material whereby a substantially planar support surface is formed, and another flag is laid on said substantially planar support surface.