US3738001A - Scraping or scoring tool - Google Patents

Abstract

A scraping or scoring tool primarily for scoring the surface of wallpaper on walls to be redecorated, so that moisture can penetrate below the surface of the paper when sprayed or steamed on stripping it from the wall. The tool is provided with a curved blade which is mounted transversely at one end of a handle and has teeth along its working edge which lie in a common plane. The handle has a mounting portion which extends at an obtuse angle to the cylindrical axis of the blade so that by tilting the blade with respect to the surface of the wall as the blade is pressed against the wall and drawn across it, the amount of contact of the toothed working edge can be decreased, thereby concentrating the pressure applied to the surface being scored along a smaller portion of the working edge and facilitating the scoring of areas where it is more difficult to penetrate the paint.

Description

ilnited States Patent [191 Roche I June 12, 1973 SCRAPING 0R SCORING TOOL [75] Inventor:

[73] Assignee: Carl Salka, Meriden, Conn. a part interest [22] Filed: Jan. 21, 1971 [21] Appl. No.: 108,283

Daniel F. Roche, Meriden, Conn.

[52] 11.8. CI. 30/171 [51] Int. Cl B261: 3/00 [58] Field of Search 30/169, 171, 172, 30/313, 317, 355, 356; 15/236 R; 146/203; 56/400.01

[56] References Cited UNITED STATES PATENTS 1,434,914 11/1922 Rhodes 30/171 2,202,264 5/1940 Peterson 30/169 3,363,316 1/1968 Skarsten 30/171 666,730 l/l90l Anderson... 56/400.01 2,697,905 12/1954 Moriarty.... 56/400.01 401,442 4/1889 Lefbure.... 30/171 2,843,932 7/1958 Ferguson 30/171 499,060 6/1893 Unsinger.... 30/171 745,753 12/1903 Adams 30/171 FOREIGN PATENTS OR APPLICATIONS 33,492 4/1922 Norway 56/400.01

Primary Examiner-Andrew R. Juhasz Assistant ExaminerGary L. Smith Attorney-Steward & Steward [57] ABSTRACT A scraping or scoring tool primarily for scoring the surface of wallpaper on walls to be redecorated, so that moisture can penetrate below the surface of the paper when sprayed or steamed on stripping it from the wall. The tool is provided with a curved blade which is mounted transversely at one end of a handle and has teeth along its working edge which lie in a common plane. The handle has a mounting portion which extends at an obtuse angle to the cylindrical axis of the blade so that by tilting the blade with respect to the surface of the wall as the blade is pressed against the wall and drawn across it, the amount of contact of the toothed working edge can be decreased, thereby concentrating the pressure applied to the surface being scored along a smaller portion of the working edge and facilitating the scoring of areas where it is more difficult to penetrate the paint.

10 Claims, 7 Drawing Figures Pmmcumnmn 3.738.001

INVENTOR. DANIEL F. ROC H E A ATTORNEYS mum-mu 3738.001

FIG. 4 FIG. 5

SCRAPING OR SCORING TOOL BACKGROUND OF THE INVENTION The present invention relates to scraping or scoring tools and it relates more particularly to tools for scoring old wallpaper on walls to be redecorated so that water can penetrate into the paper and loosen the paste when it is subsequently steamed or sprayed with water.

It has become increasingly difficult to strip old wallpaper from a wall in redecorating rooms because of the use of waterproof paints, such as latex, over the wallpaper in the course of prior redecorations. When the wall is sprayed with water or steamed, the waterproof paint prevents water from soaking through the paper in order to soften the paste. Various schemes, including the use of the toothed edge of a saw, have been devised to scratch or score the surface of the paper, or more particularly the old paint that has been applied to it, so that the water can get through. None of the devices used heretofore is really satisfactory because it is difficult to apply the proper pressure required to scratch the surface adequately for sufficient penetration of water to soften the paste without damaging the plaster or sheet rock under the paper. It is an object of the present invention to provide a scraping or scoring tool which facilitates scoring the surface of wallpaper in such a way as to lacerate it uniformly but without damaging the surface of the wall behind.

SUMMARY OF THE INVENTION The aforementioned object is achieved by providing a scoring tool that has an elongated handle by which the desired amount of pressure is applied to a rigid blade having relatively short scoring teeth formed integral therewith and substantially uniformly spaced along its working edge, the blade being drawn handle-first across the surface to be scraped. The blade is cylindrically shaped, and at least one of its curved edges forms a working edge that is provided with a row of such scoring teeth. The handle is rigidly assembled with the blade by suitable means so that the axis of its mounting portion intersects the mid-portion of the blade on its concave side. The handle extends away from the concave side of the blade and has the longitudinal axis of its mounting portion extending away from the teeth at an obtuse angle to the cylindrical axis of the blade. The ends of the scoring teeth are coplanar so that when the blade is placed in contact with a flat work-surface with the cylindrical axis of the blade disposed at a certain angle to it, all the teeth along the working edge contact the work-surface, and so that when the blade is tilted in the direction of its convex side to another angle with respect to the work-surface, the total number of teeth in contact with the work-surface becomes progressively smaller as the angle of tilt is increased.

An important advantage of the invention is that when the painted surface of the wallpaper is particularly difficult to scratch or score, greater pressure can be applied to the work-surface without increasing the pressure on the handle by tilting the blade with respect to the wall in order to reduce the number of teeth engaging the wall and thereby increasing the force exerted by each tooth on the work-surface. When the tool is held so that the handle is nearly parallel or at a small angle to the work-surface, all or most of the teeth contact the worksurface. If sufficient pressure can be applied to the painted surface to adequately score the surface with the full length of the blade engaging the work-surface, a fairly wide area can be scraped with each stroke of the tool. However, when a section of the paint is particularly tough or thick and is not readily penetrated by the teeth along the full length of the blade, the handle is simply tilted upward at a greater angle in order to increase the angle of tilt that the blade makes with the work-surface on its concave side, thereby progressively withdrawing the teeth from the surface as such angle of tilt is increased. Consequently with the blade thus tilted, the pressure exerted on the handle is applied to fewer teeth, thereby making it possible to proportionately increase the force exerted by each of the teeth still in contact with the work-surface without increasing the total pressure which is exerted on the tool.

DESCRIPTION OF PREFERRED EMBODIMENT These and other advantages of the invention will become more apparent from the detailed description hereinafter of one embodiment of the invention as shown in the accompanying drawings wherein FIG. 1 is a perspective view of a scoring tool embodying the invention, a portion of the handle being shown broken away and foreshortened;

FIG. 2 is a partial side view thereof, showing the blade and adjacent end of the handle;

FIG. 3 is a plan view of the blade only;

FIG. 4 is a top plan view of the tool with portions broken away;

FIG. 5 is a central longitudinal section of the blade end of the tool taken on the line 5-5 of FIG. 4; and

FIGS. 6 and 7 are more or less diagrammatic views of the tool, illustrating how the amount of working edge that is in contact with the wall can be increased or decreased by tilting the handle of the tool with respect to the wall.

The scoring tool of the present invention is provided with a handle or rigid shank 10 that is long enough to hold with both hands, one in front of the other. A curved blade 12 made of heavy gauge metal is rigidly mounted at one end of shank 10 transversely thereof and with its working edge 14 disposed downwardly, the broad faces of blade 12 being disposed transversely of the longitudinal axis of shank 10. At least the working edge 14 of blade 12 is provided with a row of scoring teeth 15, and in the example shown in FIGS. 1-5, all four edges are provided with such teeth, the short edges 17, 17 at the sides of the blade being used in narrow places where the full working edge 14 cannot fit. The upper or back edge 19 of the blade is used only when the blade is reversed to dispose the edge 19 in the opposite direction from that in which it is shown in the drawings, in which case it becomes the working edge.

As an assistance in applying pressure at the working edge 14 of blade 12, it is desirable to provide an auxiliary handle, such as the upstanding grip 16, which is rigidly mounted on shank 10 near the blade 12 and extends upwardly therefrom away from the working edge 14 of the blade. FIGS. 1 and 2 illustrate one way in which grip 16 may conveniently be attached to shank 10, while at the same time making it removable for use in providing a longer handle. Thus, a threaded hole 18 is provided transversely through shank 10 at the point where grip 16 is to be located. A threaded stud 20 rigidly secured in one end of grip 16 co-axially therewith fits the threaded hole 18. In order to provide solid engagement of the end surface of grip 16 with shank 10,

a flat 22 is cut in the cylindrical surface of shank l perpendicular to passage 18 such that passage 18 is located in the center of flat 22. When stud 20 on grip 16 is threaded into the passage 18 and turned down tight, the end of grip 16 seats flush with flat 22 in full surfaceto-surface engagement therewith.

In the example shown in the drawings, shank and grip 16 are made of the same round solid stock, which may desirably be a tough variety of :wood commonly used for tool handles or a light-weight metal, such as aluminum. A threaded blind hole 24 is provided in the end of shank 10 I opposite blade 12 to receive the threaded stud of grip 16 when a longer handle is required.

As illustrated in FIGS. 2, the blade 12 is mounted with a slight rake or tilt with respect to the longitudinal axis of shank 10 of its handle, so that when the cylindrical axis of the blade is perpendicular to the wall or other work-surface, the handle extends at an angle a outward away from'the work-surface which is desirably about 5 to 20, and this angle will be equivalent to an obtuse angle between the axis of the handle and the cylindrical axis of the blade of about 95 to 110. This makes it possible for the person doing the work to hold the blade perpendicular to the wall as it is being scraped without hitting the wall with some portion of the handle or scraping his knuckles along the wall. F urthermore, bearing in mind the necessity for keeping the cost of the tool as low as possible without sacrificing quality, the angle of the blade to the handle is important in providing means by which the scraping or scoring tool can be held at the proper attitude to the wall as it is-being used, while a fairly high pressure is being exerted on the tool perpendicular to the wall in order to produce the-desired scraping action on the wallpa- I per.

The blade 12 may be mounted on shank 10 in any suitable manner that holds it rigid with its handle and desirably also makes it detachable therefrom for replacement or sharpening. In the example illustrated in the accompanying drawings, a bracket 26 is provided with a central base portion 28, which is fastened to shank .10 by means of a screw or bolt 30 through a hole in the center of base portion 28 into a threaded socket 32 in the adjacent end of shank 10. Base portion 28 of bracket 26 fits flush with the end of shank l0 and has extending forwardly from its opposite ends a pair of arms 34, 34, which turn outward in opposite directions and terminate in mounting tabs 36, 36. Mounting tabs 36, 36 are bent at a slight angle to arms 34, 34 for tilting blade 12 at the desired angle a with respect to the longitudinal axis of shank 10. It will be apparent that the same tilting effect can be obtained without bending tabs 36, 36 in this manner, but instead by cutting the end of shank 10 at the desired angle and mounting bracket 26 on the inclined end surface of shank 10 with its arms 34, 34 and tabs 36, 36 extending square with each other. Numerous other ways of mounting blade 12 at the desired angle can of course be employed. Blade 12 and mounting tabs 36, 36 are suitably drilled so that the holes in blade 12 align with the holes in mounting tabs 36, 36, permitting each of a pair of mounting bolts 38, 38 to pass through both the blade and mounting tab. Wing nuts 40, for bolts 38, 38 make blade 12 readily detachable from the handle 10 so that it can be replaced, sharpened or reversed end-for-end.

In FIGS. 1-5, the scoring teeth 15 of blade 12 are shown disposed along all four edges of blade 12, but are necessary only on the one edge 14, as shown in FIGS. 6 and 7. Each of teeth 15 is desirably rectangularly shaped and uniformly spaced from adjacent teeth, the width of the spaces between adjacent teeth being approximately twice the width of each tooth. In addition, teeth 15 are sharpened on the outer or convex side of blade 12 at an angle b (FIG. 5) which may have a magnitude of around 20 to but is preferably 30. The cutting edge of each tooth is accordingly disposed on the concave side of blade 12, toward which the tool is drawn in use. g

The number and size of teeth 15 may vary according to the type of surface to be scored and are of a length greater than the thickness of the blade stock as illustrated. In practice it has been found that a blade for scoring wallpaper which has been painted over with a latex type paint is desirably 5% inches wide along its working edge 14 and has 28 to 30 teeth, each onesixteenth inch in width, evenly spaced along the full length of the edge. The teeth on the ends 17, 17 and rear edge 19 of the blade may be the same size and spacing as those on the working edge 14, or they may differ in order to obtain better results on different surfaces. It will also be apparent that the blade may be larger or smaller and may have scoring teeth on one edge only as shown in FIGS. 6 and 7.

The most important and absolutely essential aspects of the scraping tool of the present invention are the curvature of the blade 12 and its rigidity along its entire length so that it cannot be bent out of shape when pressure is applied against the wall when it is in use. Although the precise amount of the curvature of the blade is not critical, it is important that it be sharp enough to significantly change the proportion or percentage of the total length of the edge that is in contact with the wall or other work-surface when the angle of tilt between the blade and the work-surface on its concave side is increased (as illustrated in FIGS. 6 and 7) from the position shown in broken lines, in which all of teeth 15 engage the work-surface W. A curvature having a radius on the order of 7 to 10 inches has been found to be extremely satisfactory in practice. Since in this particular instance the ends of teeth 15 lie in a plane that is perpendicular to the cylindrical axis of blade 12, all the teeth will engage the work-surface when the blade is held perpendicular to it. It will also be noted that the blade must be mounted so that the handle 10 is on the inside of the curvature, or in other words on the concave side of the blade 12, so that when the handle is held at a greater angle to the wall so as to move the blade through an angle 0 (FIG. 6) from the perpendicular, the teeth at the outer ends of the blade 12 lift out of engagement with work-surface W.

It is important that the handle 10 be located on the concave side of blade 12 because if it extended from the other side, the blade would pivot about its outer ends when the handle is tilted away from the wall and this would cause the center of the blade to move out of engagement with the work-surface, which would of course be entirely unsatisfactory. In FIGS. 6 and 7, the blade 12 is shown in full lines tilted to the angle c from its broken line position in which the longitudinal axis of the cylindrical shape of blade 12 is normal to the surface W. The broken-line showing of blade 12 therefore illustrates the position in which the particular tool here shown for illustrative purposes must be held so that all the teeth 15 engage the work-surface. For the sake of clarity the handle is illustrated diagrammatically in FIG. 6 by phantom lines in both positions in which the tool is shown, the angle a being designated in the broken-line position of blade 12 as the angle between the longitudinal axis of the handle and a horizontal line through the point at which said axis intersects the blade.

In order to prevent the blade from flattening out when it is tilted with respect to the wall, it is essential that it be substantially inflexible, so that it does not bend under the pressure applied against the wall and so that its curved scraping edge does not bend into full engagement with the wall under the force applied. In the 5% inch blade mentioned hereinbefore, satisfactory rigidity of the blade is provided by making it of tool steel, one-sixteenth inch thick and 1% inches deep along its ends 17, 17. Similarly, scoring teeth 15 should be integral with the blade and short in comparison to the width of the blade, so that they do not bend or break under the heavy pressure applied to them. It will also be noted that the blade can be rocked about the longitudinal axis of handle 10 when it is tilted to the worksurface, in order to bring the teeth 15 at one end of blade 12 or the other into working engagement with the work-surface while lifting the rest of the teeth. Greater pressure can therefore be applied to the work-surface right up to a door frame, light fixture or the like.

What is claimed is:

1. A scraping or scoring tool comprising an elongated handle having an elongated mounting portion at one end thereof with a longitudinal axis, an elongated blade shaped cylindrically along its length to provide concave and convex sides and a working edge extending lengthwise thereof, said blade being formed from flat heavygauge metal stock of sufficient width in the direction of its cylindrical axis to render it substantially inflexible; and means rigidly assembling said mounting portion of said handle and said blade with said handle extending from the concave side of said blade and having the longitudinal axis of said mounting portion intersecting the mid-portion of said length of said blade and extending away from said teeth at an obtuse angle to said cylindrical axis of said blade, said blade having a multiplicity of substantially inflexible, relatively uniformly spaced scoring teeth integrally formed along its said working edge and of a length greater than the thickness of said metal stock, the ends of said teeth being coplanar such that when said working edge is placed in contact with a flat work-surface with the cylindrical axis of said blade extending at one angle to said work-surface, all said teeth contact said work-surface, and when said blade is tilted in the direction of its convex side to another angle with respect to said work-surface on its other side, while still in engagement therewith, the proportion of said teeth in contact with said work-surface progressiyely decreases as the angle of tilt increases.

2. A tool as defined in claim 1 wherein said obtuse angle is about to 1 10.

3. A tool as defined in claim 1, wherein the end of each of said scoring teeth is substantially rectangular and is beyeled on the convex side of said blade to form a sharp edge on the concave side of said blade.

4. A tool as defined in claim 3, wherein said scoring teeth are formed by providing rectangular notches in the working edge of said blade, the width of each notch being substantially equal to its depth and substantially twice the width of each tooth.

5. A tool as defined in claim 1, wherein said handle is provided with a hand grip extending laterally from said handle near said blade and in a direction away from said teeth.

6. A tool as defined in claim 1, wherein said blade is provided with scoring teeth at each end for scraping in narrow places "and has a second working edge extending parallel to but opposite said first-named working edge.

7. A tool as defined in claim 4, wherein said blade is provided with scoring teeth at each end for scraping in narrow places and has a second working edge extending parallel to but opposite said first-named working edge, said second working edge being provided with scoring teeth identical with those on said first-named working edge.

8. A tool as defined in claim 4, wherein said blade has a second working edge extending parallel to said firstnamed working edge.

9. A tool as defined in claim 1, wherein the plane in which the ends of said scoring teeth are disposed is perpendicular to the cylindrical axis of the blade.

10. A tool as defined in claim 1, wherein said mounting means removably mount said blade on said handle. t

Claims (10)

1. A scraping or scoring tool comprising an elongated handle having an elongated mounting portion at one end thereof with a longitudinal axis, an elongated blade shaped cylindrically along its length to provide concave and convex sides and a working edge extending lengthwise thereof, said blade being formed from flat heavy-gauge metal stock of sufficient width in the direction of its cylindrical axis to render it substantially inflexible; and means rigidly assembling said mounting portion of said handle and said blade with said handle extending from the concave side of said blade and having the longitudinal axis of said mounting portion intersecting the mid-portion of said length of said blade and extending away from said teeth at an obtuse angle to said cylindrical axis of said blade, said blade having a multiplicity of substantially inflexible, relatively uniformly spaced scoring teeth integrally formed along its said working edge and of a length greater than the thickness of said metal stock, the ends of said teeth being coplanar such that when said working edge is placed in contact with a flat work-surface with the cylindrical axis of said blade extending at one angle to said work-surface, all said teeth contact said work-surface, and when said blade is tilted in the direction of its convex side to another angle with respect to said work-surface on its other side, while still in engagement therewith, the proportion of said teeth in contact with said work-surface progressively decreases as the angle of tilt increases.

2. A tool as defined in claim 1 wherein said obtuse angle is about 95* to 110*.

3. A tool as defined in claim 1, wherein the end of each of said scoring teeth is substantially rectangular and is beveled on the convex side of said blade to form a sharp edge on the concave side of said blade.

4. A tool as defined in claim 3, wherein said scoring teeth are formed by providing rectangular notches in the working edge of said blade, the width of each notch being substantially equal to its depth and substantially twice the width of each tooth.

5. A tool as defined in claim 1, wherein said handle is provided with a hand grip extending laterally from said handle near said blade and in a direction away from said teeth.

6. A tool as defined in claim 1, wherein said blade is provided with scoring teeth at each end for scraping in narrow places and has a second working edge extending parallel to but opposite said first-named working edge.

7. A tool as defined in claim 4, wherein said blade is provided with scoring teeth at each end for scraping in narrow places and has a second working edge extending parallel to but opposite said first-named working edge, said second working edge being provided with scoring teeth identical with those on said first-named working edge.

8. A tool as defined in claim 4, wherein said blade has a second working edge extending parallel to said first-named working edge.

9. A tool as defined in claim 1, wherein the plane in which the ends of said scoring teeth are disposed is perpendicular to the cylindrical axis of the blade.

10. A tool as defined in claim 1, wherein said mounting means removably mount said blade on said handle.

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