SKIMMING TOOL

Abstract

A skimming tool 1 for smoothing and levelling wet plaster applied to a surface comprising: an elongate generally rectangular, flat, flexible, elastomeric web 2 and an elongate, substantially rigid handle 3 connected to and extending along substantially the length of one long edge of the web, wherein the handle is adapted to be gripped by the user

Description

The invention relates to a “ruling off” skimming tool for smoothing and levelling wet finish coat plaster applied to a surface such as a wall or ceiling.

Conventionally, plaster is applied to walls and ceilings using a plaster trowel which comprises a flat rectangular stainless steel sheet having dimensions of about 280 mm to 460 mm by 120 mm with a generally cylindrical handle mounted spaced from and parallel to the sheet. The same tool is used for smoothing and levelling the plaster once it has been applied.

A known plaster “ruling off” levelling tool, known as a ‘Darby’, comprises an extruded aluminium elongate body which may be hollow or solid. The known tool sometimes has a pair of spaced handles extending perpendicularly there from. The spacing of the handles is adjustable in some cases. However, the ‘Darby’ tool, being generally rigid and inflexible, is only useful for “ruling off” and levelling backing plaster (first coat plaster) or scratch coat sand and cement render (first coat render).

The invention provides a new long tool for skimming, Smoothing and levelling finish coat plaster (final coat plaster) reducing finish plastering times by approximately 75%. The new tool can make it possible for a single operative to tackle larger areas within short drying times/conditions due to the advantage of the increase speed. In addition another advantage of the tool is that levelling off of finish plaster on uneven substrates becomes possible giving an improved finish over substantially shorter and inflexible conventional stainless steel sheet trowels.

The invention provides a skimming tool for smoothing and levelling wet finish coat plaster applied to a surface comprising: an elongate generally rectangular, flat, flexible, elastomeric web and an elongate, substantially rigid handle connected to and extending along substantially the length of one long edge of the web, wherein the handle is adapted to be gripped by the user at any point along its length.

Embodiments of the inventions are described below with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view, from above, of a skimming tool;

FIG. 2 is a perspective view, from above, showing a short end portion of the tool;

FIG. 3 is a perspective view, from below, showing a short end portion of the tool;

FIG. 4 is an end view of the tool;

FIG. 5 is a perspective view, from above, of an end portion of the tool with an end cap in place;

FIG. 6 is an enlarged fragmentary view showing a portion of the blade of the tool;

FIG. 7 is an end view of a second embodiment of the tool;

FIGS. 8 and 9 show details of portions of the second embodiment;

FIG. 10 shows an end portion of the handle of the second embodiment; and

FIG. 11 is a plan view of a third embodiment.

The drawings show a long skimming tool 1 for smoothing and levelling finish coat plaster applied to a surface such as a wall or a ceiling. The tool comprises a plaster engaging blade in the form of an elongate, generally rectangular, flat, flexible, elastomeric web 2 which is joined to a substantially rigid, elongate handle 3 which extends along substantially the entire length of one long edge of the web. The handle 3 has a cross-sectional profile which is substantially constant along its length and is thereby adapted to be gripped by the user at any point along its length.

In the preferred embodiments, the web 2 and handle 3 have a length of 600 mm to 1500 mm, preferably about 1200 mm and the operative width of the web is 70 to 100 mm, preferably about 90 mm. If the operative width is less than about 70 mm, the tool becomes too rigid and inflexible. A tool having a length shorter than 600 mm may be useful but if the length is much shorter than that, some benefits of the tool are lost. A longer tool may be provided but only up to about 1800 mm is practicable for most users although tools of up to 2000 mm or even longer may be practicable for some users. In the preferred embodiments, the web 2 is an extrusion formed of a rigid or semi rigid PVC and has a thickness of between 1.0 and 3.0 mm, preferably about 1.7 mm. This gives the web sufficient stiffness and flexibility to operate efficiently.

The handle 3 is a hollow extrusion formed of aluminium and is substantially rigid. The handle has a generally rectangular profile comprising a first side 4 which is generally co-planar with the web, a second side 5, generally perpendicular to the web, a third side 6 parallel to the first side and a fourth side 7 parallel to the second side. The second side 5 is formed in an S profile providing a curved recess 8 extending along the handle and adapted to receive the fingertips of the user. The ergonomic design of the handle allows it to be comfortably gripped by the user at all times and especially when skimming overhead.

The handle 3 is provided with a bifurcated flange 9 at the junction between the first and second sides 4, 5 of the handle and extending generally in the plane of the web 2. The limbs 10 and 11 of the flange define a recess 12 in the form of a channel which extends along the length of the handle. The recess receives and holds the edge portion 13 of the web. Shoulders 14, 15 are formed on the web to abut the ends of the limbs 10 and 11. In the embodiment of FIGS. 1 to 6, the recess 12 receives the edge portion 13 as a snap fit by virtue of barbed formations in the recess and on the portion 13.

The lower surface of the web, which is the operative surface which engages the plaster being smoothed, is formed with a plurality of parallel grooves 18 extending along the length thereof and defining parallel ridges 16 therebetween. The ridges 16 and the flat grooves 18 therebetween are best seen in FIG. 6. This ridged surface helps to hold onto the plaster/material and distribute it evenly across peaks and troughs in the uneven substrate surface, thus facilitating an improved flatter finish. In addition the ridges also hold the surplus plaster on the tool during the operation preventing mess and spillage. The series of ridges along the surface strengthen the web but allow a slender profile and flexibility.

The hollow body of the handle is closed by end caps 17 as shown in FIGS. 5, 10 and 11.

FIGS. 7 to 11 show some further embodiments, which, except as discussed, are the same as the embodiment of FIGS. 1 to 6.

FIGS. 8 and 9 show a detailed cross-section through part of the handle and web of a second embodiment. In this embodiment, the handle is formed with a bifurcated flange 9, as before, with limbs 10 and 11 which define the recess 12. In this embodiment, the edge portion 13 of the web is received and held in the recess in a slack fit having a nominal clearance all round the edge portion 13 of about 0.125 mm at about 20° C. The edge portion 13 has an enlarged section 20 running therealong which is held in a complimentary enlarged section 21 of the recess. The enlarged sections of the web and the recess are in the form of a ball and socket when viewed in cross-section. The shapes and dimensions of the web and recess, and in particular, the loose or slack fit, permit sliding movement of the edge portion 13 of the web along the length of the recess but prevent movement of the web out of the recess in the direction perpendicular to the length of the recess indicated by arrow A in FIG. 7. In this embodiment, the direction A lies in the plane of the web. In this embodiment, the web is fitted to the handle by sliding the edge portion 13 of the web into and along the recess 12 on the handle.

The loose or slack fit of the edge of the web in the handle serves various functions. Firstly, it allows the web to expand differentially to the linear expansion of the handle. This is especially important where the handle and web are made of different materials since without this facility the web might expand more than the handle under ambient conditions. If the web is held rigidly in the handle, it may tend to kink or buckle along its length making it difficult or impossible to use correctly. Secondly, this arrangement enables simple replacement of a worn or damaged web into a handle. Other web profiles of rigid or semi-rigid design may be introduced for other different tasks to be performed.

FIG. 10 shows an end portion of the handle with an end cap 17 which is a push fit into the open end of a hollow extruded handle and is retained by catches 23 snapping into apertures 24. The end cap has an opening 25 which permits drainage of water from within the hollow handle. A portion of the end cap overlies the open end of the recess 12 to retain the web in place.

FIG. 11 shows a tool in which the end caps are held in place by self tapping screws 26 which are screwed into the open ends of the enlarged section 21 of the recess 12. The end sections of the web have cut away portions 27 which prevent engagement with the screw. The length of the web is selected such that it can expand more than the handle without engaging the screws or the end caps.

In an alternative construction (not shown) the handle and web may be formed of a single plastic extrusion formed of a single material, preferably PVC. In another alternative, the handle and web may be made of different plastic materials, or simply of differently coloured plastic materials blending together at a join along the length of the tool.

In a yet further embodiment (not shown) the handle can be solid and made from wood or other suitable material. In this embodiment the web may be extended to overlie the first side of the handle and be glued or otherwise fixed thereto.

Claims

1. A skimming tool for smoothing and levelling wet finish coat plaster applied to a surface, comprising: a plaster engaging blade comprising an elongate generally rectangular, flat, flexible, elastomeric web having a proximal edge portion and a distal edge portion, and an enlarged section at the proximal edge portion of the web; andan elongate, substantially rigid handle configured to connect to the plaster engaging blade, wherein the handle is adapted to be gripped by a user at any point along a length of the handle, wherein the handle defines a recess extending along the length of the handle, and wherein the recess comprises a channel and an enlarged section, the channel having a first height adjacent the enlarged section and the enlarged section having a second height greater than the first height;wherein, when the handle is connected to the plaster engaging blade: the enlarged section of the plaster engaging blade is received in the enlarged section of the recess in the handle with a slack fit that permits sliding movement of the plaster engaging blade in a direction parallel to a length of the recess but prevents movement of the plaster engaging blade in a direction perpendicular to the length of the recess;the proximal edge portion of the web is received in the channel; andthe web extends outwardly from the handle and the distal edge portion of the web is spaced apart from the handle.

2-3. (canceled)

4. A skimming tool as claimed in claim 1, wherein the enlarged sections of the web and the recess are in the form of a ball and socket in cross-section.

5. A skimming tool as in claim 1, wherein the handle has a generally rectangular profile comprising a first side generally parallel with the web and a second side generally perpendicular to the web and being formed with a curved recess therealong adapted to receive the fingertips of the user.

6. A skimming tool as in claim 1, wherein the handle is hollow and wherein the skimming tool further comprises removable end caps configured to close off opposite ends of the handle.

7. A skimming tool as claimed in claim 6, wherein the end caps, when in place, overlie opposite open ends of the recess to prevent lengthwise movement of the plaster engaging blade out of the recess.

8. A skimming tool as claimed in claim 1, wherein the handle and the web are formed by extrusion.

9. A skimming tool as claimed in claim 1, wherein the handle is formed of aluminum and the web is formed of PVC.

10. A skimming tool as claimed in claim 1 wherein the web and the handle both have a length greater than about 600 mm.

11. A skimming tool as claimed in claim 10, wherein the web and the handle have a length of 600 mm to 1500 mm.

12. A skimming tool as claimed in claim 11, wherein the web and the handle have a length of about 1200 mm.

13. A skimming tool according to claim 1, wherein an operative surface of the web comprises a plurality of parallel ridges extending along a length of the web and located proximate the distal edge portion of the web.

14. (canceled)

15. A skimming tool as claimed in claim 1, wherein the web comprises a first material having a first coefficient of thermal expansion and the handle comprises a second material having a second coefficient of thermal expansion less than the first coefficient of thermal expansion.

16. A skimming tool as claimed in claim 1, wherein the handle further comprises a bifurcated flange defining the channel, the bifurcated flange comprising a first limb and a second limb spaced apart from the first limb.

17. A skimming tool as claimed in claim 16, wherein the plaster engaging blade further comprises a first shoulder extending from a first side of the web and a second shoulder extending from a second side of the web, and wherein when the handle is connected to the plaster engaging blade, the first and second shoulders abut distal ends of the first and second limbs.

18. A skimming tool as claimed in claim 17, wherein the first limb has a first width and the second limb has a second width smaller than the first width, and wherein the first shoulder is spaced apart from the proximal edge portion of the web by a first distance and the second shoulder is spaced apart from the proximal edge portion of the web by a second distance less than the first distance.

19. A skimming tool as claimed in claim 1, wherein the handle extends along substantially the length of the proximal edge portion of the web.

20. A skimming tool as claimed in claim 1, wherein the enlarged section of the recess is located at a proximal-most end of the recess.

21. A skimming tool as claimed in claim 20, wherein, when the handle is connected to the plaster engaging blade, a substantially constant nominal clearance is defined extending around the proximal edge portion of the web and the enlarged section of the blade.