Title IMPROVEMENTS IN AND RELATING TO SKIMMING TROWELS.

DESCRIPTION

The present invention relates to improvements in trowels, particularly but not exclusively to plastering trowels, such as those used for skimming internal surfaces.

A wide variety of trowels exist in the marketplace for applying and spreading mortar, plaster and the like onto a surface. Trowels are produced in various shapes and sizes to enable skimming and rendering of different types of surface. Generally, a trowel comprises a small hand-held tool with a flat pointed _, blade, but rectangular, circular and corner trowels also exist. The majority of trowels, particularly those used ^' for skimming plastered surfaces, are comprised of stainless steel although it is known to provide rigid plastic trowels for external rendering.

The requirement for a plasterer to have a large number of metal trowels is both expensive and cumbersome. It requires the plasterer to have a large box for storage of all the tools and means that the plasterer must climb up and down his ladder in order to change his trowel to that which is most appropriate to the particular area he is plastering. The stainless steel blade is also dangerous, particularly if it is a worn metal trowel which is razor sharp and dropped from a height. Moreover, it is extremely hard work to provide a satisfactory finish to a surface by skimming the surface using a metal trowel.

Yet a further disadvantage of the prior art trowels is the inability to reach into small difficult to reach areas with the trowel, such as behind radiators and the like.

It is an object of the present invention to provide an improved trowel that allows for enhanced skimming of a surface with reduced effort on the part of the user.

It is a further object of the present invention to provide an improved trowel that reduces the total number of trowels required by the user.

Accordingly, a first aspect of the present invention provides a skimming trowel comprising a handle and a member attached thereto for providing a flat surface characterised in that the flat surface is comprised of an at least partially flexible impact and ultra-violet resistant plastics material.

Preferably, the flat surface is comprised of a plastics material, more specifically, a polyvinylchloride (PVC) material, for example but not limited to calendered PVC, penta rigid polyvinylchloride, high molecular weight polyethylene, high density (equal to or greater than 0.94 Ig/ cm ) polyethylene, medium density (0.926 - 0.94Og/ cm ³ ) polyethylene, lineal low density (0.915 - 0.925g/cm ³ ) polyethylene, polypropylene, and substituted variants thereof.

When the polyvinyl material is penta rigid polyvinyl chloride, it is especially penta rigid polyvinylchloride having a white gloss finish. However, it is most preferred that that polyvinylchloride material chosen for the trowel is calendered polyvinylchloride (PVC).

It is also preferred that the PVC material, most especially the calendered PVC has a thickness of between 1 and 45 mm in thickness. More specifically, it is

preferred that the PVC material, especially, the calendered PVC has a thickness of between 1 and 35 mm in thickness. Even more preferred is that the PVC material, most especially the calendered PVC has a thickness of between 1 and 15 mm in thickness. However, the most preferred thickness for the PVC material, especially the calendered PVC is 1 to 5 mm in thickness. This later thickness is most preferred for the PVC material and especially the calendered PVC material as it produces trowels according to the present invention with preferred properties.

The flat surface may be of any suitable shape, such as rectangular, circular or triangular to form a pointed blade. Alternatively, the member may be L-shaped for forming two substantially perpendicular flat surfaces for providing a corner trowel.

The plastics material more especially, the calendered PVC material may be provided as a coating on the flat surface but, more preferably, the entire member is comprised of the plastics material, especially, calendered PVC. In addition, the member may be laminated, that is, it may comprise two or more layers of the plastics material, for examples two or more layers of the calendered PVC material. Alternatively, the laminated member may comprise a layer of calendered PVC and a layer of another PVC material that is compatible with the calendered PVC material.

It will be appreciated that the combination of plastics materials in the laminated member will be selected to provide a trowel which has the required properties of flexibility and durability as are required by the trowel in accordance with a first aspect of the present invention.

In a preferred embodiment of the present invention, a plurality of flat surfaces of different shapes and sizes are provided for attachment to the member or handle of a trowel. To this end, a second aspect of the present invention provides a kit of parts for a trowel, the kit comprising at least one accessory for providing a flat surface for attachment to a trowel, the accessory having securing means for its temporary attachment to the trowel.

Preferably, the kit of parts includes a conventional small rectangular trowel having a handle and a member attached thereto for providing a flat surface. The flat surface of the at least one accessory is of a different size and/or shape to the flat surface of the trowel. It is envisaged that the kit includes multiple accessories each having a flat surface of a different shape and/or size.

In a preferred embodiment of the present invention, the flat surface of the accessory is provided by at least one sheet or layer of plastics material. Preferably the plastics material is more specifically, a polyvinylchloride (PVC) material, for example but not limited to calendered PVC, pentarigid polyvinylchloride, high molecular weight polyethylene, high density (equal to or greater than 0.941 g/ cm ) polyethylene, medium density (0.926 - 0.94Og/ cm ³ ) polyethylene, lineal low density (0.915 - 0.925g/cm ³ ) polyethylene, polypropylene, and substituted variants thereof.

However, it is most preferred that calendered polyvinylchloride (PVC) is chosen as the material for providing the flat surface of the accessory.

More preferably, one side of the accessory, preferably comprised of calendered polyvinylchloride (PVC) is in the form of a flat surface and the other side is provided with securing means for its temporary attachment to a trowel. Preferably,

the securing means comprises at least two opposing flaps, dimensioned to receive opposing sides of a trowel. It is preferable for the flaps to be in the form of two parallel strips of material that are secured to the surface along their outer edges only. An additional flange may be provided extending at least partially between one end of the strips to act as a stop for the trowel.

It is preferable to provide a rim of material extending between the other ends of the strips. Preferably a gap is provided between the rim and the strips.

The flange and/or rim may be partially or completely secured to the surface.

It is to be appreciated that the strips, flange and rim may be any suitable size and shape depending upon the size and shape of the accessory and the size and shape of the trowel to which the accessory is to be attached. It is preferable for the distance between the inner edges of the strips to be approximately the size of the handle of the trowel, with the strips being dimensioned in order to cover the rest of the blade thereby enabling the blade of the trowel to be securely retained therein.

Alternative securing means may be provided for attaching the accessory to the trowel, such as a snap-fit arrangement. However, the provision of longitudinal slots for passage of the edges of the blades has the advantage of enabling the trowel to be pulled partially free of the accessory to enable the flat surface of the accessory to reach into areas previously not possible due to the positioning of the handle of the trowel.

Preferably, a casing is provided for housing the accessories and, more preferably, the trowel also. For example, the casing may be in the form of an open envelope or folder having a central slot for receiving the handle of the trowel. More preferably, the casing comprises a series of sleeve or pockets that are each dimensioned to correspond to a particular size of accessory and are bonded together, preferably in order of size. The casing may include a smallest sleeve or pocket that is provided with a longitudinal slot for receiving a handle of a trowel.

It is preferred for all the parts of the accessories and the casing to be formed of a partially flexible plastics material, more specifically, a polyvinylchloride (PVC) material, for example but not limited to calendered PVC and penta rigid PVC. However, it is most preferred that all the parts of the accessories and the casing comprise calendered PVC.

The flat surface may also be provided for attachment to a pole or rod to provide a trowel that may reach high surfaces, such as ceilings. Preferably the flat surface is attached to the rod or pole in the same manner as the other accessories of the kit. The flat surface may be rotatable with respect to the pole. Locking means may be provided to lock the flat surface at a desired orientation. A buffer material, such as a foam, may be provided between the flat surface and pole to aid in distribution of pressure to the surface.

For a better understanding and to show more clearly how it may be carried into effect, reference will now be made by way of example only to the following

experimental work investigating the material most suitable for use in the trowel of the present invention and accompanying drawings.

Polyvinyl chloride (PVC) is the dominant member of the family of vinyl compounds. PVC and especially calendered PVC, is an ideal material for use in the trowel and trowel kit according to the present invention because of its properties: namely, the material for use in the trowel according to the present invention is preferably required to be: chemically inert, resistant to water corrosion, have a high strength to weight ratio, be electrically and thermally non-conductive, be highly versatile (that is, it can be processed in a number of different ways such as calendaring), is practically maintenance free, for example it does not need to be specially treated, such as oiling, and is also a relatively low cost material.

Whilst a range of PVC materials may be used to produce the trowel and kit of the present invention for example but not limited to, high molecular weight polyethylene, high density (equal to or greater than 0.941 g/ cm ) polyethylene, medium density (0.926 - 0.94Og/ cm ³ ) polyethylene, lineal low density (0.915 - 0.925g/cm ³ ) polyethylene, polypropylene and derivatives thereof, calendered PVC with a preferred thickness of between 1 and 45mm thickness, more preferably, 1 and 35mm even more preferably 1 to 15 mm and especially 1 to 5mm, is chosen for producing the flat surface of the trowel and kit described herein.

The trowel of the present invention comprised preferably of calendered PVC with a thickness of preferably 1 to 5 mm has several advantages over traditional steel trowels, for example, the trowel of the present invention is:

Light weight (density of steel = 7.85g/cm ³ . density of PVC = 1.32 - 1.37g/cm ³ ), has increased flexibility, is easier to use because of its lightweight properties and also provides for a decreased time required to become proficient in using the trowel and also in the ability to achieve a smooth finish as required by both professional and nonprofessional plasterers. In addition, the trowel of the present invention requires less time to apply a plaster finish to a surface to be plastered, is easier to use when applying a plaster finish to small areas or when working on hard to reach areas such as corners and behind radiators or fittings. Furthermore, the trowel of the present invention is preferred in terms of health and safety issues as the trowel does not develop a sharp edge during use. One of the major problems with traditional steel trowels is that the edges of the trowel become sharpened during use which obviously has health and safety implications for any users of the trowel anyone working in the vicinity of persons using the trowel. Finally, the trowel of the present invention is also safe to use around electrical wiring and/or fittings due to the non-conductive properties of the PVC material used to manufacture the trowel and the trowel kit.

Finally, in order to demonstrate the properties of the trowel and kit disclosed herein an assessment was carried out to compare the ease of use of the trowel/kit according to the present invention with a traditional steel trowel as follows:

Two sections of a wall each measuring 2m by 6m were marked out. Plaster was applied to the first section using a traditional steel trowel whilst plaster was applied to the second section using the trowel of the present invention. For each of the sections of wall, the wall surface and plaster mix used were identical. The steel trowel and

trowel of the present invention were the same size and the application of plaster test was performed by a professional plasterer with 20 years experience.

The process of plastering the wall was subdivided into a number of key stages (see Table 1 below) and the time taken to complete each stage was recorded for both the traditional steel trowel and the trowel of the present invention.

Table 1.

Therefore, it can be seen from the above table that the time taken to successfully plaster an area of wall using the trowel of the present invention compared with a traditional steel trowel is reduced in all stages of the plastering process.

In the accompanying drawings:

Figure 1 is a perspective view of a trowel made with a material according to a first aspect of the invention;

Figures 2a and 2b are respectively a front and side elevation of a corner trowel made with a material according to the first aspect of the invention;

Figure 3 a is a top plan view of one trowel accessory for a kit according to the second aspect of the present invention;

Figure 3b is a side elevation of the trowel accessory of Figure 3a shown attached to a trowel;

Figure 3 c is a front elevation of the trowel accessory of Figure 3 a shown attached to a trowel;

Figure 4 is a top plan view of an alternative trowel accessory for a kit according to the second aspect of the present invention;

Figure 5a is a perspective view of a housing for a kit of parts according to the second aspect of the present invention;

Figure 5b is a side view of the housing of Figure 5a, shown containing a trowel;

Figure 6a is a side elevation of a trowel according to another embodiment of the present invention; and

Figure 6b is a plan view of a flat surface for attachment to the trowel shown in Figure

6a.

Referring to Figure 1 of the accompanying drawings, a skimming trowel is shown comprising a handle 2 attached to a shank 4 provided with a flange 6 at right angles thereto which is fixed to a member 8, the underside of the member forming a flat surface or blade for skimming a wall, ceiling or the like. The trowel is distinguishable over those of the prior art by the member being preferably comprised

of calendered PVC. The member is preferably approximately between 5 and 15mm in thickness. It has surprisingly been found that the provision of a member of this material in contrast to, for example, a stainless steel or nylon blade greatly reduces the effort required in providing a satisfactory finish with the trowel.

It is to be appreciated that the PVC plastics material may be provided as a coating but best results have been achieved, by forming the entire member/blade from the PVC plastics material, most preferably calendered PVC and being around 2- 15mm in thickness. Figures 2a and 2b illustrate how a corner trowel may also have its flat surface or blade comprised of this material. The trowel again comprises a handle 2' having a head 8' attached thereto comprised of two flat surfaces 10 substantially perpendicular to each other. The entire head is comprised of calendered polyvinylchloride, PVC.

Figures 3 a to 4 of the accompanying drawings illustrate a kit of parts for forming a trowel according to the second aspect of the present invention. The kit comprises one or more accessories for attachment to a small rectangular trowel (such as that described in Figure 1 albeit conventional metal trowels would also be suitable for purpose). The accessory shown in Figures 3a to 3b is to increase the size of the trowel to enable larger areas to be skimmed more quickly. For example, the trowel without the accessory may have a flat surface dimension of approximately 10cm x 20cm whereas the accessory provides a flat surface dimension of 20cm x 30cm.

The accessory has a thickness of preferably between 1 and 5 mm in thickness and is comprised of one or more layers of calendered polyvinylchloride, PVC. The intended

underside is a flat smooth surface 10 but the intended upper side of the accessory is provided with two parallel longitudinal strips of material 12,14 (preferably of the same material as the flat surface) and a flange 16 connecting one end of the strips to each other. The flange and strips are only secured to the flat surface along their outer edges thereby providing flaps. The strips are spaced apart by a width substantially equal to the width of the small trowel. Additionally, a rim or ledge of material 18 (again preferably being of the same material as the strips and flat surface) is provided across the opposing ends of the strips but is not in contact therewith to provide a gap 20. The rim is completely secured to the flat surface. The strips are generally rectangular but the ends thereof adjacent the rim are cut obliquely to form guides 22.

In this manner, a user of a small trowel can attach the accessory when he requires a trowel of a larger surface area. The blade 8 of the trowel is slotted into the compartment formed by the strips 12, 14 and flange 16 of the accessory and is retained therein by means of the strips and rim 18, as shown in Figures 3b and 3c (not to scale). The larger trowel is then ready for use and has the additional advantage of enabling the user to be retain the familiar handle of the small trowel. Furthermore, it is possible to partially withdraw the trowel from the securing means thereby providing a flat surface extending further forward of the handle than is the case with conventional trowels. This enables skimming of a surface that is normally out of reach, such as behind a radiator. It also removes the need for the plasterer to carry more than one trowel at a time. This is clearly desirable given that much of the work is carried out whilst the user is up a ladder.

Figure 4 of the accompanying drawings illustrate an alternative accessory that may form part of a kit of parts according to the present invention. Identical features already described in relation to Figures 3a to 3c are given the same reference signs and only the differences will be discussed in detail, The underside of the accessory is again flat and the upper surface is provided with securing means in the form of parallel strips 12, 14, a flange 16' and rim 18 to enable it to receive and retain the small trowel. However, one end 30 of the flat surface is pointed to enable the trowel to be used in relation to angled surfaces.

It is to be appreciated that a wide variety of accessories may be provided in different shapes and sizes having means for attachment to a conventional trowel. For example, an accessory may be provided corresponding to that described in Figures 3 a to 3 c having a similar width to a conventional small trowel but being of greater length (eg. 11cm x 30cm).

The specific dimensions and positioning of the strips, flanges and rim are not critical to the invention and will depend upon the size of trowel to which the accessory is to be attached and the size and shape of the accessory.

A casing for example in the form of an open plastic envelope or folder may be provided for retaining the accessories forming the kit and the small trowel. Figures 5a and 5b of the accompanying drawings illustrate a preferred housing or casing for storing the accessories of the kit according to the present invention. The housing 50 comprises of a series of plastic sleeves 52, 54, 56, each sleeve being dimensioned to receive an accessory of a particular size, with the sleeves being mounted in order of

size and bonded together. Each sleeve is open along one side only and each accessory may be slotted into its appropriate sleeve for storage purposes. A backboard 58 (optional) is also provided to increase the rigidity of the housing. The smallest sleeve or pocket 52 is dimensioned to receive a small rectangular trowel and is provided with a longitudinal slot 60 extending inwardly from the open end of the sleeve for passage of the handle 2 of the trowel (see Figure 5b). Preferably, the housing is comprised of the same plastics material as the accessories.

Figures 6a and 6b illustrate a further trowel according to the first aspect of the present invention. The trowel again comprises a member 90 having a flat surface 100, the flat surface being of a plastics material. The member is attached via a layer of foam 102 to a long pole or rod 104 for forming a handle. In the illustrated embodiment, the flat surface 100 corresponds to that attachable to a small trowel, that is having attachment means 106, 108, 110 on its underside for retaining the member 90 attached to the pole.

In this manner, the trowel may be used to finish high surfaces, such as ceilings, without the need for a ladder or scaffolding. Optionally, the angle of the head of the trowel may be adjustable to enable the angle of the member to correspond to the angle of the surface being skimmed.