GB2335226A - A trowel blade with a layer of hard chrome disposed at its edge - Google Patents

Abstract

A trowel blade 12, preferably notched for spreading and metering material, has a flat rectangular blade with at least one linear edge. A stripe 61 of hard chrome is disposed on the bottom working side of the blade 12 along the linear edge.

Description

1 TROWEL 2335226 The present invention is directed to a trowel having a

hard chrome plated layer and more particularly to a notched trowel having a hard chrome plating disposed as a stripe across the teeth of the trowel.

Notched trowels are known in the art. Carefully selected notch sizes, shapes and locations are utilized to both spread and meter adhesives or other spreadable material onto select surfaces. The blade is formed with a plurality of notched teeth along one or more edges, typically two edges, which permits the application of the adhesive to a floor or other flat surface. During use, the trowel is played at an angle to the surface, pulling the teeth of the trowel along the surface. The teeth of the notched trowel become abraded and worn through use, and some of the teeth may bend or otherwise be moved away from the plane of the trowel. Such wear and bending of the teeth change or destroy the metering characteristics of the trowel. It would be highly desirable to provide a notched trowel with teeth that resist wear and are less prone to bend and abrade, and so preserve the original metering characteristics of the trowel.

According to the present invention, a trowel blade comprises a flat blade having a bottom working surface and at least one linear edge forming a boundary of the working surface, and having a stripe of hard chrome disposed on the said linear edge of the working surface.

Preferably, notches are provided on a portion of the linear edge to create notched teeth.

Preferred examples of a trowel blade of the present invention will be described with respect to the accompanying drawings, in which:

2 Fig. 1 is a perspective view of a notched trowel; Fig. 2 is a bottom view of the blade of a trowel having a different style of notch teeth than that of the 5 trowel of Fig. 1; Fig. 3 is a side view of the trowel blade of Fig. 2 with enlarged depth for purposes of description;

Fig. 4 is a perspective view of a portion of the teeth of the trowel blade of Fig. 2; and Fig. 5 is a top view of portions of a few of many possible different teeth embodiments for notched trowels.

3 Referring to Fig. 1, a trowel 11 is constructed from a blade 12, a handle support 15 and a handle 17. Blade 12 is formed from a rectangular sheet of metal, for example steel, with a plurality of notched teeth 18.

As shown in Figs. 2 and 3, another trowel blade 13 has a different style of notch teeth 19. Blade 13 is f lat meanina that it has a low prof ile Blade 13 includes an upper surface 21 and a lower surface 23 disposed in parallel planes and defining the thickness of blade 13. The blade includes two longer edges 25, 27 disposed parallel to the longitudinal axis 29 of the blade, and two shorter edges 31, 33 disposed orthogonal to axis 29. As shown in Fig. 2, notched teeth 19 are disposed along one longer edge 25, and one shorter edge 31. The edges 27, 33 are straight un- notched edges, but either or both could be notched, while edges 25, 31 are notched to form teeth 19. The blade embodiment of Fig. 2 illustrates twenty-two separate teeth 19 along edge 25 and eight separate teeth 20 along edge 31. Each tooth 35 along edges 25, 31 is shaped the same except for corner tooth 37 which may have an irregular shape due to its location at the intersection of 4 edges 25, 31 and due to a variety of other factors including notch geometry and blade edge dimensions.

tooth 35 is formed or forming notches or openings 39 in the sheet. Each notch 39 is cut inwardly from the edge of the metal sheet forming each tooth so that (Fig. 4), two side surfaces 43, 45, a bottom surface 47 and a top surface 49. The two side surfaces 43, 45 curve outwardly at their inward extent to meet with another side surface of the adjacent tooth. This notched tooth configuration is referred to as U style, and is shown diagrammatically in Fig. 5 at 51. As shown in Fig. 5, other notched tooth configurations may be used including a flat V style 53, a V style 55 (also shown in Fig. 1), a square style 57, and a big U style 59. Many other notch patterns are possible. Referring to Fig. 2, a hard chrome layer in the form of a stripe 61 is plated onto the lower working surface 23 of 20 blade 13. As shown in Fig. 2, stripe 61 is of a width X (which, for example, may be 12 inch (12.5 mm)) and covers each tooth of edge 25. Stripe 61 has a linear inner edge 63 which defines the extent to which the stripe extends laterally on Referring to Figs. 2 and 4, each directly from metal sheet 13 by cutting it includes a rectangular end surface 41 the bottom surface toward the longitudinal axis 29. A linear outer edge 65 of the stripe is disposed parallel to the inner edge 63 and to the longitudinal axis 29 of the blade. Inner edge 63 is defined by a locus line disposed 5 parallel to axis 29 and is established a distance from edge 25 so as to protect the teeth from wear without the chrome layer covering the entire width of the blade 13.

The stripe layer is cosmetically appealing to the user as a narrow stripe of hard chrome positioned parallel to the longitudinal axis of the blade. Stripe 61 provides a wear surface to protect the teeth and edge 25 of the trowel.

As shown in Fig. 4, outer edge 65 of the stripe lies in the plane of the outer end surface 41 of the teeth. The inner edge 63 of the stripe is disposed in a plane tangential to the notches 39. The hard chrome layer is electroplated onto the blade by masking the surfaces where the chrome is not wanted or by limited immersion of the blade in the plating bath.

As shown in Fig. 4, a portion of the stripe layer 61 is removed on the far right tooth for purposes of description so that the bottom surface 47 may be viewed. However, layer 61 covers the entire bottom surface 47 of each tooth. if some portion of chrome plates onto the side surfaces 43, 45

6 of the teeth, a jagged appearance results which may be undesirable from a cosmetic point of view.

Chrome layer 61 is formed by plating hard chrome onto the blade using conventional plating techniques. The hard chrome is a well-known conventional substance. Chrome layer 61 is approximately.0020 inches (0.05 mm) in thickness, i.e.

0015-.0025 inches (0.038 to 0.064 mm) in thickness.

To avoid unnecessary cost and to provide a cosmetically appealing product, the layer 61 is plated only as a stripe of a width X. The notches open through the stripe as shown in Fig. 2. As the trowel is used, typically at 45 to 900 angles with the floor or hard surface, the chrome layer contacts the floor or surface providing a hard relative nonwearable surface. Alternatively, a different embodiment may be formed where the entire edge of the blade is immersed into the plating bath to a certain depth, resulting in a total encapsulation of the edge, providing a stripe on both the upper and lower surfaces of the blade. 20 A finishing trowel (not shown), similar to trowel 11 but without any notches, may be constructed with a hard chrome layer in the form of a stripe disposed along each of the two longer edges of the trowel. The stripe may be a 1 J 7 narrow stripe of the size of the chrome stripe shown in Fig. 2. one edge of the stripe is disposed at the edge of the trowel, similar to Fig. 4, and the other edge of the stripe extends toward the longitudinal axis a stripe-width distance of inch (1.25 mm), or a distance sufficient to protect high-wear edge areas without covering the entire width of the trowel blade.

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Claims (15)

1. A trowel blade comprising a flat blade having a bottom working surface and at least one linear edge forming a boundary of the working surface, and having a stripe of hard chrome disposed on the said linear edge of the working surface.

2. A trowel blade according to Claim 1, further comprising a second linear edge disposed parallel with the said linear edge, a third linear edge orthogonal to the second linear edge and a fourth linear edge orthogonal to the second linear edge, the stripe having two end edges disposed respectively at the third linear edge and the fourth linear edge.

A trowel blade according to Claim 1 or 2, wherein the bottom working side of the blade has a high-wear area and wherein the stripe has one lateral side disposed at the first said linear edge and being of a width sufficient to protect the high-wear area from wear.

4. A trowel blade according to any one of the preceding claims, wherein the stripe has one lateral side disposed at the first said linear edge and extends to a distance no greater than the longitudinal axis of the blade.

5. A trowel blade according to any one ofthe preceding c_laims, wherein the stripe is a thin layer of hard chrome of uniform thickness.

6. A trowel blade according to any one of the preceding claims, wherein the stripe of hard chromeis electroplated onto the blade.

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7. A trowel blade according to any one of the preceding claims, wherein the layer is planar.

8. A trowel blade according to any one of the preceding claims, wherein the layer is approximately.002 inches (0.05 mm) in thickness.

9. A trowel blade according to any one of the preceding claims, in which the first said linear edge includes a portion having a plurality of notches creating notched teeth, and in which the stripe of hard chrome is disposed on the bottom working side of the blade on the notched teeth.

is

10. A trowel blade according to Claim 9, wherein each of the notches extends inwardly into the blade from the first said linear edge to a distance no greater than a locus line parallel to the first said linear edge, the stripe having two side edges disposed parallel with the first said linear edge, the stripe having one side edge disposed at the f irst said linear edge of the blade and the other side edge disposed at the locus line.

11. A trowel blade according to Claim 9 or 10, wherein each of the notches extend an equal distance into the blade-

12. A trowel blade according to any one of Claims 9 to 11, wherein the blade has a second linear edge, a portion of which includes a plurality of notches creating notched teeth, and wherein the layer of chrome is disposed solely on the notched teeth of the first said linear edge.

13. A trowel blade according to any one of Claims 9 to 12, wherein the notches are equally spaced along the portion of the linear edge.

14. A trowel according to any one of Claims 9 to 13, wherein the portion is substantially the entirety of said linear edge.

15. A trowel blade substantially as shown in, or as described with respect to, the accompanying drawings.