GB2167005A - Tool for building construction - Google Patents

Abstract

A tool for preparing joints for repointing by removing old mortar has a base plate 1 through which protrude a rotary bit 12, a rotary brush 11 and a transversely journalled guide wheel 18, all in longitudinal alignment. The brush 11 and bit 12 are operatively connected by gears 8 and 9 for common drive by an electric motor. The tool is pushed manually by handles 3 and 5 along a joint: the bit 12 breaks up the mortar to a desired depth, the brush 11 removes the broken mortar, and the wheel 18 runs in the cleared joint as a directional guide. Alternatively, a similar base plate can be modified on its top surface as an attachment, to hold a power drill with the bit protruding below the plate at 45 DEG forwardly and the chuck driving a separate brush similarly protruding but at 45 DEG backwardly. <IMAGE>

Description

SPECIFICATION Construction industry tool This invention relates to a tool for use in building construction, repair and maintenance, embodied as an independent tool or as an attachment assembly for a handheld electrically powered rotary drill.

Courses of stone or concrete blocks, and more especially courses of brickwork, are laid with their individual units side by side on an underlying horizontal bed of mortar, and with a vertical layer of mortar between each unit. The exposed surfaces of these horizontal and vertical layers of mortar are typically then trowel-finished to a neat appearance before they set. Eventually, to improve the decorative appearance and/or as a maintenance procedure after many years, it becomes necessary to repoint these joints. This involves chipping out the mortar to a depth of say two centimeters along each horizontal and vertical joint and then refilling the groove so formed with wet mortar, which is worked into the desired surface configuration before it hardens and sets.The procedure is very la- bour-intensive and tends to damage the corners of the bricks while forming the groove by removing adjacent hardened mortar, e.g. by a hammer and chisel.

A quite separate technique in the field of building construction also involves removal of a channel from hardened concrete, mortar or plaster. This is the "chasing" of a groove to accommodate an electrical conduit, or gas or water pipes, within an existing structure.

Occasionally, moreover, it is desired to decorate a plain surface layer of concrete, mortar or plaster by the provision of incised grooves, e.g. as dummy jointing to improve appearance.

The present invention provides equipment with its primary utility as a tool for use in preparing the points in brickwork for re-pointing, but which can also be used for the other purposes indicated above, and which can be embodied as an independent tool or as an attachment to an existing powerdrill. The tool in accordance with the invention can be utilised with cementitious material, but possibly can be used to provide a groove in wood or like substrate especially if only a narrow groove is required.

In one aspect the invention provides a tool for removing portions of a substrate so as to leave a groove or channel, comprising (a) a base plate with a defined forward edge (b) a plurality of longitudinally aligned members extending through the base plate, comprising successively (reckoned from the forward edge) (i) at least one rotary bit (ii) at least one substrate-removal member separate from or combined with (iii) at least one guide protrusion and (c) a drive to rotate at least the or each bit; whereby movement of the operating tool along a surface of a substrate material causes (i) the or each bit to break up the substrate with which it comes into contact (ii) the or each removal member to at least clean out the broken material and leave an empty groove and (iii) the or each guide protrusion to move along the groove and provide guidance for continued movement.

The substrate material envisaged is usually a hardened cementitious material e.g. concrete, mortar or plaster, and in particular a joint of such material. It can possibly however be wood especially if the bit is of relatively narrow gauge.

The substrate-removal member can be another bit, removing either loose material or existing loose material plus another layer of substrate. It can be a suction, or blowing head. It can be, and preferably is, separate, but could be part of the guide protrusion, e.g. a guide wheel-brush. Usually, however, it comprises at least one separate rotary brush.

The guide protrusion could be a low-friction stud, e.g. mounted flexibly to give a "movable pivot" point whereby the bit can be traversed up a joint and not just along. Usually, however, it is one or more guide wheels, as discussed below.

Thus, in a preferred form the invention consists in a tool for removing a hardened cementitious material so as to leave a groove or channel, comprising (a) a base plate with a defined forward edge (b) a plurality of longitudinally aligned members extending through the base plate, comprising successively (reckoned from the forward edge) (i) at least one rotary bit (ii) at least one rotary brush and (iii) at least one transversely journalled guide wheel and (c) a drive to rotate the or each bit and the or each brush; whereby movement of the operating tool along a surface of a cementitious material causes (i) the or each bit to break up the cementitious material with which it comes into contact (ii) the or each brush to clean out the broken material and thus leave an empty groove and (iii) the or each guide wheel to ride in the groove and provide guidance for continued forward movement.

In one form of the invention the axis of rotation of the or each bit and of the or each brush is substantially orthogonal to the base plate for ease of construction. One bit and one brush are preferred, though other constructions may be used e.g. two bits (one narrower and one wider) followed by a single brush. Usually the or each bit and the or each brush are operatively interconnected for rotation by a common drive.

In another aspect the invention provides an attachment for a handheld rotary electric drill, comprising a base plate with a defined forward edge, having attached thereto (a) at an upper surface at least one clamping support for holding and securing the body of the said drill in such a location that a drill bit can extend to protrude forwardly at approximately 45" through a suitable base plate orifice near the said forward end (b) also at an upper surface, a support for a rotary bush capable of rotation by the held and received drill, the bush capable of receiving and holding a rotary brush to extend rearwardly and also protrude through an orifice in the base plate and (c) a guide wheel jour nalled transversely in an orifice rearward of the brush orifice, so as to protrude from the base plate: the three said orifices being longitudinally aligned.

Conveniently the clamping support is shaped to hold the lower forward part of the drill, and has a hinged and clamping cover shaped to fit over and hold the upper forward part of the drill. Optionally, moreover the attachment may possess a support shaped to hold the end of the handle of the drill.

The base plate may be provided with further transversely journalled rollers whereby it is spaced from the surface is use. Usually, the forward plate edge is turned upwards.

Another aspect of the invention consists in the combination tool i.e. the attachment and powerdrill combined.

Still further aspects consists in methods of (a) cleaning a joint in brickwork or the like prior to repointing, in which such a tool, or combination tool is pushed along at least the horizontal mortar courses between the bricks or the like, and (b) generally, chasing a groove in a surface of hardened cementitioius material using the abovedefined tool or combination.

The invention will be further described with reference to the accompanying drawings, in which: Figure 1 is a side view of an independent tool in accordance with a first embodiment of the invention; Figure 2 is a side view of an attachment in accordance with the invention fitted to a power-drill; and Figure 3 is a view from below of Figure 2.

In Figure 1, a base plate 1, of metal or rigid polymer, has an upturned forward edge 2 and an inclined gripping handle 3 attached to a rearward part of the plate 1 and terminating in a surrounding member 4 from which protrudes at right angles to the plane of the drawing a straight handle 5 of circular cross-section. Within and held by surrounding member 4 is an electric motor (not shown) with connecting lead 6 at the rearward end of inclined handle 3.

A central drive shaft 7 of the motor meshes at gears 8,9 respectively with a parallel drive shaft 10.

Each gear 8 or 9 is hollow at its axis. Gear 8 receives rotary brush 11 and gear 9 rotary bit 12 provided with radially extending longitudinal vanes 13. Reinforcing bearing structure 14 can be provided, common to bit 12 and brush 11. The operative portions of bit 12 and brush 11 protrude through base plate 1 by a desired amount.

Base plate 1 has journalled within its thickness a number of rollers. Two front rollers 15 are transversely aligned and of the same radius as each other and as the single rear roller 16. Moreover two intermediate rollers 17 (one not shown) also possess the same radius, and are equally spaced from a thinner larger-diameter central roller 18 located in the central line of the base plate. Figure 3, described in more detail below, shows typical rollers used with a different brush arrangement.

Rollers 15,16,17 should all be of the same radius, but their actual common radius or their individual lengths, are not critical, and their exact locations can also vary, as will be made clear below. Roller 18 however, should be thin enough and of large enough diameter to fit within a channel in a substrate, as torn out by bit 12, whereby it can act as a guide wheel.

The operation of the device should be generally apparent from the foregoing description of its construction. The current is switched on and the tool grasped with two hands, one around inclined handle 3 and the other around handle 5. it is pushed (from left to right in the drawing) along the joint between (for example) courses of brickwork. Bit 12 rotates and vanes 13 bite into the mortar. Brush 11 then brushes the broken pieces of mortar out of the joint. Wheel 18 follows in the cleaned joint to act as an alignment guide. Rollers 15, 16, and 17 generally support the plate 1 clear of the brickwork, although occasional sliding along the surface is not important. Because of the staggered vertical joints, however, the smaller diameter rollers generally exercise the "spacing" function and ensure clearance of the joint to a standard recommended 20 mm depth.

Pressures on the bit 12 and brush 11 are resisted by support bearing structure 14. Upturned forward edge 2 lifts the plate over occasional lumps of mortar e.g. at vertical joints.

Various modifications may be made to the tool as shown. Thus instead of a permanent electrical supply at 6 a rechargeable unit shown at dotted lines at 19 can be used, to give a unit self-contained in use. Also, it is possible to arrange a succession of bits and/or brushes, all with their centres of rotation longitudinally aligned, using some intermeshing gear arrangement elaborated from gears 8 and 9. For instance, a narrower bit can be followed by a broader bit and then a brush.

Moreover, wheel 18 can be mounted for resilient vertical displacement, i.e. so that it can ride up out of the end of a discontinuous joint. This is of particular value in preparing the discontinuous but aligned vertical joints in brickwork.

A particularly valuable modification is to embody the tool as an attachment to a handheld power drill. This is shown in Figures 2 and 3 which show an electric power drill 20 of conventional type and an attachment 21 derived from base-plate 1, and associated structure of Figure 1.

Drill 20 has a handle 22 with on-off switch 22 and indicator 24, and rotary chuck 25 to hold a bit 12 with vanes 13 as before. Around chuck 25 is peripheral crown gear 26 for a tightening key, as known per se. Preferably the tool also has a further handle, as handle 5 in Figure 1, also known per se.

Attachment 21 has base plate 1, upturned front edge 2, and rollers 15,16,17 and 18 as before. It also possesses supports and cla,-nps for attaching drill 20, namely, (a) rear support 27 for handle 22 (b) body support 28, shaped internally to receive the forward part of the drill 20 and (c) cover or clamp 29, hinged at 30 and secured on the other side (behind the drill, not shown) with a wing nut which can be opened to receive the drill 20 and closed to secure it in place.

Above base plate 1 is an angled support member 31 for holding a toothed rotary bush 32 meshing with crown gear 26 to receive brush 11. Brush 11 protrudes at an angle of 45Q rearwardly through hole 33 in base plate whereas bit 12 protrudes at an angle of 45 forwardly through forwardly open slot 34 (see Figure 3).

Use of the device is as before. There is advantage in the 45 angles of the bit and brush since less lateral pressure is exerted. Also, use of a conventional power drill cuts down prime cost of tooling for manufacture.

Figure 4 shows a yet further embodiment of the equipment, in diagrammatic longitudinal section.

A base plate 41, again of metal or rigid polymer, has an upturned edge 42 and supports a polymeric housing 43 the rearward part of which is formed to constitute a gripping handle 44. Within the housing is electric motor 45, with a vertical shaft 46 extending downwardly to a chuck 47 mounting a main bit 48 with its rotary axis vertical. Upon shaft 46 is gear wheel 49, meshing with gear wheel 50 upon parallel shaft 51. This shaft 51 is also provided with a chuck 52 at its lower end to accommodate when desired a lead, or break-up, bit 53 of smaller diameter than main bit 48.

Beneath gear wheel 49 is a pulley 55 and beneath the pulley is a fan structure 56.

Towards the rer of the equipment is a third shaft 57 provided with pulley 58 and carrying a brush 59 beneath the base plate. Pulleys 55 and 58 are connected by belt 60.

Outside of the housing, at the front, is a vertical location vane 61. A like vane, or vanes 62, is provided to one or both sides of the housing (see Figure 4a). The vanes are typically in a colour contrasting with that of the housing, and define from above lines which when continued located the axis of the main bit 46.

As shown the requirement, with two bits, is used for chasing a groove in a surface, i.e. for continuing essentially in a straight line as defined by the axes of "breakup" bit 53, main bit 48 and brush 59.

As before, the preliminary or break-up bit removes a narrow channel of material. The main bit then breaks up the remainder to the desired eventual channel width, the existence of the narrower channel allowing this to be effected with less overall power consumption. The rotary fan 56 removes this bulk of broken dry material through a suitable exhaust duct, not shown. Finally, as the tool progresses, the brush 59 passes along the channel, rotating on its axis by means of the belt drive 55-6058 to clean out residual debris.

For routing mortar in brickwork it is preferred to operate using the main bit 48 with preliminary bit 53. Operation is as before, mortar usually being a fairly soft substrate so that bit 48 works without the preliminary break-up channel. Horizontal courses of mortar can be removed by operating in straight lines as before; vertical courses can be removed by swinging the tool up or down (the straight handle grip readily permitting this) so that there is a general pivoting effect about brush 59 as the bit 48 progresses along a vertical course of mortar.

Various modifications may be made within the embodiment shown in Figure 4. For example, the brush 59 could be replaced by a simple projecting stud, less valuable for cleaning but still permitting priority. The brush, or stud, can be springloaded. A driven brush is preferred, as shown, but a simple projecting non-rotary brush is also possible.

Moreover, bit 48 is described above as a simple rotary bit, but a "percussive" bit, with a suitable drive, could also be used.

The surface nature of the main bit e.g. bit 48 is also of some importance. As shown in for example Figure 1, a bit with vertical blades can be used.

However, Figures 6 to 8 show a further preferred shape with good aggressive clearance properties.

The bit shown in Figure 6 has a shank 71 which, in the example given, is threaded at 72 for fitment into a suitable rotary holder. At its outer or working end it has a shallow conical formation 73 to which are fitted three blades 74 located mutually at 120 each progecting somewhat beyond the cylindrical portion of the bit. Around the curved surface of the bit are shown seven circumferential rows of teeth 75.

Figure 6a shows a typical tooth 75 in enlarged perspective view. It will be seen that each tooth has a somewhat sloping forward end surface 76 and an arcuate ridge 77 which eventually meets the curve surface of the bit 71.

Although the drill is shown with a threaded end for attachment to a suitable rotary holder it is of course possible to have non-circular shanks as shown in Figure 7a, 7b and 7c for fitment into a rotary chuck by a manner well known per se.

A general view of the bit from below can be seen in Figure 8. Blades 74 project outwards to the same extent as the tips of the teeth 75. The undercut or sloping surface 76, and the angular ridge 77 are each shown clearly in Figure 3.

Figure 9 is a general external view of the embodiment of Figures 4 and 5.

In use, the bit is mounted in the a hand held power tool as shown in the Figures 1-4 and pushed into a surface of mortar or plaster (for example) to an extent such that all of the teeth 75 are submerged. The blades 4 facilitate this initial hole formation. The bit then can be moved in any transverse direction and will cut out a recess by virtue of teeth 75 in the substrate. This can be used, for example, in chasing out a recess or electrical conduits, or in removing a portion of the mortar between adjacent courses of brickwork preparatory to re-pointing.

It will be immediately apparent to the man skilled in the art that differences of detail can be made in from the particular bit as shown. Examples of such differences will now be discussed, it being understood that they are of general applicability and relate individually or in combination back to the broad definition of the invention given, prior to the specific description of the drawing.

While there are preferably three blades upon the pointed end, two or four could also be used. More than four blades tends not to be so effective.

It is preferred if the bit is embodied as a notional 8 millimetre bit, but there is no reason why a larger size (e.g. 15 millimetre) should not also be manufactured. The included circular conical angle at the end (which end can also be part circular if desired) is generally somewhere between 90 and 160 , for example 120 .

There is of course no particular constraint upon the number of teeth 75 to be used upon the bit, or upon the particular shape or arrangement of these teeth. While a patterned arrangement, e.g. as shown in Figure 1, is preferred, the teeth can if necessary be randomly arranged around the surface. Also, the teeth could be arranged in separate lines whereby the tail of the arcuate edge 77 does not extend backwards beyond the line of the next front faces. An advantage of this would be to make the front faces easier to sharpen by a single sharpening action upon a number of aligned faces.

If the blades are to be arranged at a number of levels, as shown in Figure 1, there will preferably be three such blades at each level. There could of course be any number from 1 to 4 such blades. it is also possible to arrange the blades so that instead of having their forward tips in longitudinal lines they follow helical lines around the blade.

The shape of each blade is preferably as shown with the forward face sloping towards the eventual direction of motion. The angle by which the blades slopes is preferably from 0 to 45 and more preferably from 10 to 20 , for example 15 , to a line joining the tip of the blade to the centre of rotation of the bit. It is much preferred to have the blades sloping in this direction since the bit is more aggressive in its action. Some effect would be achieved even if the blade were to slope backwards, but this is not recommended. While in the example shown the blades are relatively elongate with a lengthy ridge 77 extending for an appreciable distance round the circumferential surface, it is of course also within the scope of the invention to make them considerably shorter provided that strength is not undesirably sacrificed. Shorter blades are easier to work with to the extent that they can be sharpened without interference from adjacent blades.

Figure 9 shows in a general external view the embodiment of Figures 4 and 5. It further shows a suction duct opening, behind the main bit, a transverse handle, an on-off switch, and a dust outlet.

Either or both of the bits can be percussive as well as rotary. The following brush can also have an up-and-down, springmounted, capability.

Claims (25)

1. A tool for removing portions of a substrate so as to leave a groove or channel, comprising (a) a base plate with a defined forward edge (b) a plurality of longitudinally aligned members extending through the base plate, comprising successively (reckoned from the forward edge) (i) at least one rotary bit (ii) at least one substrate-removal member separate from or combined with (iii) at least one guide protrusion and (c) a drive to rotate at least the or each bit; whereby movement of the operating tool along a surface of a substrate material causes (i) the or each bit to break up the substrate material with which it comes into contact (ii) the or each removal member to at least clean out the broken material and leave an empty groove and (iii) the or each guide protrusion to move along the groove and provide guidance for continued movement.

2. A tool for removing a hardened cementitious material so as to leave a groove or channel, comprising (a) a base plate with a defined forward edge (b) a plurality of longitudinally aligned members extending through the base plate, comprising successively (reckoned from the forward edge) (i) at least one rotary bit (ii) at least one rotary brush and (iii) at least one transversely journalled guide wheel and (c) a drive to rotate the or each bit and the or each brush; whereby movement of the operating tool along a surface of a cementitious material causes (i) the or each bit to break up the cementitious material with which it comes into contact (ii) the or each brush to clean out the broken material and thus leave an empty groove and (iii) the or each guide wheel to ride in the groove and provide guidance for continued forward movement.

3. A tool for removing a hardened cementitious material so as to leave a groove or channel, comprising (a) a base plate with a defined forward edge (b) a plurality of longitudinally aligned members extending through the base plate, comprising necessarily (reckoned from the forward edge) (i) at least one rotary bit (ii) at least one rotary substrate-removal brush and (c) a drive to rotate the or each bit and the or each brush: whereby movement of the operating tool along a surface of a cementitious material causes (i) the or each bit to break up the cementitious material with which it comes into contact and (ii) the or each brush: whereby movement of the operating tool along a surface of cementitious material causes (i) the or each bit to break up the cementitious material with which it comes into contact and (ii) the or each brush to clean out the broken material and thus leave an empty groove, while simultaneously riding in the groove and providing guidance for continued movement.

4. A tool as claimed in claim 2 or claim 3 in which the axis of rotation of the or each bit and of the or each brush is substantially orthogonal to the base plate.

5. A tool as claimed in claim 2, 3 or 4 having one such bit and one such brush.

6. A tool as claimed in any of claims 2 to 5 in which the or each bit and the or each brush are operatively interconnected for rotation by a common drive.

7. A tool as claimed in any of claims 2 to 6 having electric drive means and a rechargeable electrical storage unit, whereby the tool is self-contained.

8. A tool as claimed in any of claims 2 to 6 having electric drive means and a connection to an external source of current.

9. A tool as claimed in any of claims 2 to 8 in which a fan structure is provided around the rotary axis 8, and for rotation with, the or each bit to at least initiate substrate and/or dust removal as the cementitious material is broken up.

10. A tool as claimed in claim 1 and substantially as herein described with reference to Figure 1.

11. A tool as claimed in claim 1 and substantially as herein described with reference to Figures 4 and 5.

12. An attachment for a handheld rotary electric drill, comprising a base plate with a defined forward edge, having attached thereto (a) at an upper surface at least one clamping support for holding and securing the body of the said drill in such a location that a drill bit can extend to protrude generally forwardly through a suitable base plate orifice near the said forward end (b) also at an upper surface, a support for a rotary bush capable of rotation by the held drill, the bush capable of receiving and holding a rotary bush to extend generally rearwardly and also protrude through an orifice in the base plate and (c) a guide wheel journalled transversely in an orifice rearward of the brush orifice, so as to protrude from the base plate: the three said orifices being longitudinally aligned.

13. An attachment as claimed in claim 12 in which both forward and rearward protrusion is about 45".

14. An attachment as claimed in claim 12 or 13 in which the clamping support is shaped to hold the lower forward part of the drill, and has a hinged and clamping cover shaped to fit over and hold the upper forward part of the drill.

15. An attachment as claimed in claim 12, 13, or 14 further possessing a support shaped to hold the end of the handle of the drill.

16. An attachment as claimed in claim 12, 13, 14 or 15 in which the bit orifice is a slot open at the forward edge of the base plate.

17. A tool as claimed in any one of claims 1 to 11 or an attachment as claimed in any one of claims 12 to 16 in which the base plate is provided with further transversely journalled rollers whereby it is spaced from the surface in use.

18. A tool as claimed in any one of claims 1 to 11 and 17, or an attachment as claimed in any one of claims 12 to 16 in which the forward edge is turned upwards.

19. The combination tool formed by the attachment as claimed in any one of claims 12 to 18 with a power drill secured thereto as described in claim 9.

20. The tool as claimed in any one of claims 1 to 18, or the combination tool as claimed in claim 19, having both a generally longitudinal handle and a generally transverse handle.

21. The combination tool as claimed in claim 19 and substantially as described with reference to Figures 2 or 3.

22. A method of clearing a joint in brickwork or the like, prior to repointing, in which a tool as claimed in any of claims 1 to 18 or a combination tool as claimed in any of claims 19 to 21, is pushed along at least the horizontal courses between bricks or the like.

23. A method of chasing a groove in a surface of hardened cementitious material in which a tool as claimed in any of claims 1 to 18 or a combination tool as claimed in any of claims 10 to 21 is pushed over the surface.

24. A tool as claimed in any one of claims 1 to 18, or a combination tool as claimed in any of claims 19 to 21 in further combination with an attached rotary bit having a bladed shallow generally pointed end and a toothed curved surface.

25. A tool, or combination tool, as claimed in claim 24 in which the teeth are arranged equispaced in circumferential rows with three teeth to a row, the teeth of successive rows being displaced by 60 to those of adjacent rows.