GB2241530A - Multi-purpose plastering trowel - Google Patents

Abstract

An adapted plasterers trowel incorporating in addition to the trowels traditional functions, means whereby the trowel may replace the use of additional and separate tools or devices required in the preparing, rendering, plastering and finishing of but not only, angularly related and/or geometrically subjective surfaces. The adaption providing a gauging face 12, fitted with a retractable and slidable abutment member 18, a trowelling and abutment face 11, graduated scales 14, 15 and 17, removable serrated plate 25, and extension bar 27. These means providing for the trowels additional use as a reference scale, a square gauge, a pre-settable single subjective plain scraping device, a dual subjective plain scraping device, a corner trowel and a serrated adhesive applicator blade. <IMAGE>

Description

IMPROVEMENTS TO PLASTERING TROWELS BACKGROUND TO THE INVENTION Tnis invention relates to devices used in the preparation, rendering and final plastering of a surface and so is particularly- but not only - useful for the finishing trades in the building industry.

Tne finishinq of such a surface involves tne aDDlication of a layer of render, and subsequently possibly one, but usually two ski coats of plaster. Both render and plaster coats are applied to the surface, musing a traditional plasterers trowel, which same tool is employed during the said process, in the application, scraDinci, cutting ana spreading, of the applied plaster or reaper to achieve, so far as is possible a surface which is approximately true and square.

A straight edge of sufficient length (2 meters for a large plain surface), is then employed to adjust the approximated surface, by scraping away high areas, ana indicating low areas. the trowel being used to relocate or remove excesses as applicable, such that a true ruled surface is provided.

It will be aDDreciated that the applied material must be so ruled for quantity and placement before the trowel is employed for the final smoothing and finishing of the surface.

The nature of this repeated application, adjustment and finishing requires a tool specifically adaptea to the several requirements oi the separate operations for which it is employed, in order that tine wasting and inconvenient changes of tools be eliminated so far as is possible. A traditional plasterers trowel has evolved to employ features which allow it to be the single tool used for the oDerations involved in the rendering ad plastering of a piain surface.

A variety of other surfaces require to be rendered or plastered, however, demanding further constraints of both subjective geometry ana technical features for which the traditional trowel cannot be employed, so that several additional and inconvenient tool changes are repeatedly required.

Tne case of single geometrically subjective surfaces are illustrated by the side and top faces of a reveal of a window, door or the like, in that it is important that the rendering is carried out to provide surfaces substantially at right angles to the outer surface of a wall, souare with a trame set in the reveal. It is common practice prior to the ren@ering of a reveal to affix metal corner angle beads vertically to eacn of the two outer corners o the side taces or tne reveal and one horizontally to the outer corner of tne top face of the reveal.The achievement of relative squareness being accom@lished normally, by settling the angle beads in small sufficiently spaced dabs of wet quick setting plaster and adjusting its distance irom the square set frame elements using the long wedge of the traditional plasterers trowel. The current angle bead position is retained by placement of the operators finger, held on tne long edge. The trowel is moved to the next dab, the required adjustment noted, and tne angle bead tapped in by the required amount, using the same lon edge of the trowel.Further reference must then be made to the previous Doint (The finger position having been lost as a result of tapping). Tunis repeated reference and adjustment is repeated to achieve a visual compromise of all previous construction. (Bricklaying & Carpentry).

Following setting of the angle beads, a set-square of sufficient thickness such that it may firmly abut the frame element, Is used to locate the position on the frame at which the final plaster coat of the intended side face will be square with both frame and angle bead.

This position is marked.

To assist the removai of excess render a further device is employed, having an edge which is scraped along the appropriate corner angle, square to the main wall.

This scraping device may have been adapted by the provision of a strip or pe or the liKe, arranged to extend from a side mutuaily at right-angles with its scraping edge, this extension serving to gulot the device by running along a frame element. in this way marking is eliminated, and a square and true side face may be achieved.

Once the scraping device has been set to provide the appropriate surface, a traditional trowel is used to liberally apply render to the faces to be workea, and the scraping device re-applied to remove the excess.

On completion of each pair or taces or a reveal (tor example) ane rignt-hanå side face, and the horizontal top face, a corner trowel, having two trowelling faces substantially mutually at rignt-angles, is employed in finishing the right-anqled junction of the two renderea or plastered faces. This use is repeated for the junction of the remaining two faces.

Plaster skim coats are applied in a like manner employing the trowel in its traditional use. Further to final finishing, it is sometimes required to affix tiles of ceramic or the like material. in this case a serrated blade is used to regulate the application of adnesive.

The case of two angularly related and geometrically subjective surfaces is illustrated in rendered or plastered steps (in, for example a swimming pool or the like),in that it is important that each tread be rendered level and substantially parallel with its preceding tread, and each riser be rendered true and substantially at riht- angles to its associated tread. Common practice in this case is to affix corner angle beads to the outer corners of each treaa and riser, in like manner to the outer corners of a reveal, and to scrape ana adjust applieo render on tread and riser separately and progressively through the series of steps, reference being continually maae to the previously finished ana hardened tread or riser. Further tools employer being a set-square, trv-square, corner trowel and special- purpose controlled scraping or towelling devices.

The above methods are however open to inaccuracies, are tie consuming and troublesome in that they reauire the use of numerous implements in addition to the traditional plasterers trowel, which tool must also be employed intermittently, for the application, adjustment and final finishing of the render or plaster, in the usual way.

SUHMARY OF INVENTION This invention seeKs to provide a solution to the problems of rendering and/or plastering surfaces with subjective geometry in addition to piain surfaces, by extending the functions for which the traditional trowel may be employed such that one and the same implement may be used tor any surface to be rendered or plastered.

Accordingly the present invention provides the traditional plastering trowel with an additional gauginq and trowelling face formed from substantially "U" shapea right-angular channel affixed to, or formed as an extension of, its original trowelling blate, coincident with the trailing edge thereof anu or the side thereof, remote from the oriqinal trowelling surface, so as to provide a further trowelling ana abutrient face colncident wlth, and substantially at right-angles to, the trailing edge of the trowel.

This mounting avoids hinoerance of the traditional use of the trowel such that the planing face may continue to ilex as tar as possible in its traditional use and the leading edge may continue to cut and spread in its traditional use and the two ionq edges may continue to scrape and spreaa in their traditional use.

(Reference is made to Figure 3 of the accompanying drawings.

It will be appreciated that the provision of the further troweiling and abutment face conveniently allows for the trowel to be further used in the gauging of a reveal by using the trowelling plate as a set square of sufficient thicKness, in the manner before mentioned for location of the position of the reveal face to be rendered or Plastered. Figure 3b.

The provision of the further trowelling and abutment face coincident with the trailing edge, and substantially at right-angles to the original trowelling face, allows the trowel to be used in finishing corner junctions of two co-joining plains, in the manner before mentioned employing a corner trowel. Fiqure 3e.

A further gauging face is provided by the uppermost face of the channel, substantially at right-angles to the trowellino and abutment face, and parallel to the original trowelling plate, whereon is mounted a retractaDle abutment member slidably adjustable in a direction substantially at right-angles to the trowels two long edges.

Means is provided to lock the abutment member in both an adjusted abutment position or a retracted non-abutment position. Use ot the abutment member in its extended position allows either ot the trowels long edges to be used in con3unction with tne abutment member in the manner before mentioned employing a scraping device usco to remove excess render from both the left-hand and right-hand side taces and the horizontal top face of a reveal. Fiaure Jc.

The gauging face is provided with a convenient scale such that the abutment member may be adjusted or re-adjusted remotelv rrom the reveal face, enabling the abutment member to be positionea at a predetermined distance from its abutment position. The scraping eage will then undercut the render for the predetermined thicKness of subsequent plaster, to provide for final coats to be finished square and true, ana to provide for minimal use of materials. Figure 3c.

On the side of the trowellinq plate remote from the oriqinal trowelling face ana adjacent to either or both of its lon edges, a measuring scale is provided tot reverence in setting tie angle beads square in their plaster dabs, in tie manner before mentioned (Fig 3a) A aemountable extension to the additional trowelling and abutment face is provided such that the extension may be fitted and secured to provide a ruling face coincident with the troweis trailing edge and mutualy at right angles with either of the trowels lonq egges. The abutment member may be adjusted and secured in the extension as hereinbefore described.Use of the demountable extension in conjunction with the abutment member allows the trowel to be used for tne simultanious qeometricaily subjective ruling of both tne tread and trite riser of a step or the like, and without reference to any other treaa or riser in series of steps or the like.

On the side ot the trowelling plate remote from the original trowelling tace and adjacent to the sbine, are proviaed means tor attachment of a serrated trowelling edge tor use in the manner of a serrated blade. Figure 3d.

The locking means ot the before mentioned abutment member may comprise a screw-threaded fastener adapted to clamp tne abutment member in its extended adjusted position, or in its retracted o- abutment position. This locking gleans is preferably a dome@ headed set screw, engaging a threaded hole in the abutment member such that said abutment member may be securely locked, preferably Dy one hand only.

The domed headed form of the set-screw avoiding physical damage to a hand gripping the handle of the said trowel.

SPECIFIC EMBODIMENT OF THE INVENTION By way of example only, one specific embodiment of a plasterers trowel adapted according to the invention will now be described in detail, reference being made to the accompanying drawings, In which: Figure 1 Is a perspective view of an un-modified Dlasterers trowel.

Figure. 2a Is a perspective view or a trowel adapted according to the invention.

Figures 2b and 2c Are sections showing the abutment member in its b) Extended, ana c) retracted positions.

Figure 3 a,b,c,d,e, &alpha; t, show persbective views or the modiried trowels extended uses.

Ine trowel incorporating tne improvements of this invention is used, in adaition to its traditional functions, for the variety of extra functions required (for example) in the rendering of a reveal, and makes redundant, the several other implements currently used in the rendering and/or plastering of similar geometrically subjective surfaces. In addition to its traditional uses of application, adjustment ana smoothing of the render or plaster.

Referring to Figure 2, the invention comprises a substantially right angled U channel 1U, one side face or which is securely mounted on the trowelling plate 1 of a traditional plasterers trowel as snown in Figure 1., sucli that the centre face li of "U" channel lü, is coincident with trailing egge 5, ana on the side of trowelling plate 1 remote from trowelling surface 7. Preferably, the two outer edges 13a and 13b, of the "U" channel 10, are angled inward and upwara from lon edges 2 and 3 of trowelling plate 7, to allow maximum traditional use of the long edges 2 & 3, of trowelling plate 7, and to allow said long edges to be used in the scraping of excess render.

kectangular gauging-face 12 is formed from the outer face of "U" channel 10, remote from and substantially paraliel to, trowelling plate 7 and mutually at right-angles with centre face 11. Gauging- face 12 is provided with lip 22, extending the length of gauging face 12. Preferably, a graduated scale 17 is provided, extending the length of gauging-face 12.

A retractable abutment member 18, is mounted over lip 22, and gauging-face 12, which abutment member is substantially rectangular and is so formed internally as to be retractable from, or expendable over, face 11 and restrainec in both the extended or retracted position by 11b 22. The abutment member 18 is slioable along gauging- face 12 and restrained to move suDstantially at right-angles to face 11, by location lip 22. Abutment member i8 is arrangea to project only a set distance beyona face 11, ana may on reiease of domed set-screw 21, be withdrawn from projection so as to provide tor convenient traditional use of trowelling surface 7.

In order to secure the abutment member 18 in a required position, Domed set-screw 21, is threaded into Abutment member 18 so that its conical boint engages with gauging-face 12. inner faces 23 and 24, of Abutment member 18 are thus drawn to engage sauarely with underside of gauging-face 12 to ensure secure and even clamping. In tne above way, the abutment member 18 may easily be re-positioned in its projecting abutment position, and may be re-positioned at any point along scale 17.Scales 14 and 15 are provided adjacent to, ana extending the length of, long edges 2 and 3, on the side of trowelling plate 1 remote trom trowelling surface 7.

Snap brackets 26, are provided adjacent to both sides ot spine 9, enabling serrated edge plate 25, to securely attacn to eitner side of trowelling plate 1, remote from trowelling surface 7, such tnat its serrated edge may extend over and substantially parallel to, lon edge 2 or 3.

extension Dar 2s, is provided with a centre section ot dimensions substantially identical to "U" channel 10, together with spigots 28 & BR< iY which may be fitted inside "U" channel lu to replace abutment member is. Preferably the angled ends of spigots 26 & 2 coincide witn one or the otner of the angles edges 13a or 13b or "U" channel iu, Domed set screw 31, may be engaged in threaded hole J2, in either spigot, to provide secure locKing of Extension Bar 27 in "U" channel 10. insertion from either end of "U" channel 10 providing for left of right nanded working as required. Abutment member 18 may then be positioned in Extension Channel 2E, and clamped in either its retractea or extended position.

The tool is used in the following manner when applieo as the single device employed in the rendering and plastering of a reveal.

Scales 14 and 15 adjacent to lonq edges 2 and 3 respectively, are used to provide reference while angre beads are set on the outer corners or the two side races and top face of the reveal, so as to be square and vertical, or horizontal as appropriate. (Fig 3a) Tne tool is then used in the manner of a set square, by placing the centre face 11, now used as an abutment face, firmly in contact with the face of a lower horizontal frame element fittea within the reveal, the abutment member 18, restinq on the uDper surface of the horizontal frame element. The appropriate ions edge, (3 toi exam@le) being moved forward to engage the right-hand angle bead.The tool thus tinds its own position such that the lon edge 3 view be suDstantlaliy at right-angles to both tne lower frame element, ano tne outer race of the wall.(Fig.3b) in this position, the abutment membe@ it is now released by loosening domed set-screw 21, and is then suitably adjusted along gauging face 12, until it engages the vertical frame element.

Preferably if it is aesirco to under Cut render for a preset thlcRness or subsequent plaster, rererence may be made tO the scale 17, the tool withdrawn frorr; its abutment ano tie abutment member it moved back a specific distance along the scale 15, in oroer that ionq edge 3 will project further into the renoer by tat specific distance The abutment member it is then ciamped securely in this position, preferably requiring one hand only, by means of the domed set-screw 21 when the abutment member 18, has been secured in the appropriate position along gauging-face 12, the tool is removed from its engagement with the frame and angie bead, and usco to liberally apply render in the traditional manner.

The tool is then re-enqaaea in its previously set position ana its long cage 3, drawn along that surface of the reveal. Alignment is maintained by the abutment member 18, engaging and running on the frame element, using the latter as a rail, wnile the long edge runs on the angle bead. Drawing the tool thus along the angle bead and maintaining engagement ot the abutment member 18 witn tne frame element, long edge 3, scrapes away excess render so as to proauce a finished. surface in the plane of the set position of long edge 3, with respect to abutment member 18.(Fig 3c) During this action, the excess render is collected and restrained by the spine 9, particularly but not only when a top tact is view.

The positioning ot the trowelling and abutment race il reiative to trailing edge 5, and the symmetry or scale 17 allows use of either lonq edges 2 or 3 for scraping, tnus tne tool may De easily reversed adjusted and used for both right-hand and left-hand side faces, and tne tob tact or a reveal.

As each pair or taces is ruled, the tool may further be usea in the manner of a corner trowel, Abutment member it being adjusted to its retracted position, centre face 11, coacts with trowelling surface 9, to form a pair of trowelling surfaces mutually at right- angles about trailing edge 5.(Fig 3e).

The tool may then be used in the traditional manner in tne subsequent plastering and finishing of tne reveai.

In the rendering and finishing of steps or the liKe, the tool is used in its extended functions as aDove, for the gauging and fitting of anqle beads at tnt outer junction of each riser ano tread, ano ii its tradltlonai functions for the application ana approximate surfacinq of both risers and treads.

further extended functior is obtained by the release and removal of Abutment member is, to permit Extension bar 27 to be located arid locked into the appropriate side of "U" channel 10, thus providing an extension to the trailing edge 5, of trowelling face 7. Abutment member 18 is fitted in Extension Channel 28, and adjusted in its extended position with rererence to scale zu, to provide the required riser depth.

The tool may now be used to conveniently ruie tne approximated surface of both treaa ano riser in the sante pass, lona edge 3, (for example) engaging the tread face of angle bead (34 in Fig 3f), and extension channel 28 engaging the riser face of angle bead (33 in Fig 3f), abutment member 16 engages the tread face of angle bead (33 in Fig 3f).

it will be appreciated tat both riser and tread iii be ruled simultaneously, long egge 3 scraping the tread face, while tralling edge 5 ano its extension 28 scrape the riser race. Further advantage being gained in that the arrangement requires no contact wltn iower or higher steps in the series such that all sucn steps may be ruiea in a single ruling sequence. (Fig 3f) Un hardening of the finished plaster, serrated piate 25, may be snapped into position unuer snap brackets 26, providing for the troweis use as a serrated blaoe for the application or adhesive prior to tile affixment. (Fig 3d).

Claims (1)

1). An adapted plasterers trowel incorporating in addition to the trowels traditional construction, means whereby the trowel may be additionally employed to replace the use and function o a separate tool or device required in the preparing or rendering or plastering or tinishing of, but not only, annularly related ano/or geometrically subjective surfaces.

2). A device according to claim 1, wherein means is provided ror trite troweis additional use in replacing the use of a separate adjustable scraping aevice, tor rulinq one geometrically subjective surface.

3). A device according to claim 1 or claim 2, wnerein means is provided for the trowels additional use in replacing tnt use of a separate adjustable scrapinq aevice for simultaneous ruling or two or more angularly related and geometrically subjective surfaces.

4). A device accoroing to any precealnq clam, wherein means is provided for the trowels additional use in replacing the use or a separate corner trowel.

5). A device according to any preceding claim, wnerein means is provided for the trowels additional use in replacing tne use of separate square-gauge.

b). A device according to any preceding claim, wilerein a graduated scale is provided for remote adjustment of the abutment member of the adjustable scraping means.

7). A device according to any precding claim, wnerein a graduated scale is provided on one or both of the trowels long edges.

8). A device according to any precding claim wherein means is provided for the trowels additional use in replacing a serrated blade for the application of adhesive.

9). A aevice according to any preceding claim, wherein any or all of the extension or function means are demountable from tne traditional plasterers trowel, 10). A device extending the use of a traditional plasterers trowel ana substantially as hereinbefore described with reterence to and as illustrated in the accompanying drawings.