US3818592A - Knife for peeling off stickers and the like - Google Patents

Abstract

A knife has a flat reverse face and a beveled cutting face on the opposite side with a bevel dihedral angle of approximately 15* and a truncated extreme cutting edge in the form of a blunt leading edge, narrow regions respectively of the beveled cutting face and the reverse face immediately adjacent to and extending along the leading edge being further beveled with minute bevel angles each of approximately 2.5* relative to the beveled cutting face and the reverse face. When a knife of this shape is advanced with the leading edge in front into the thin adhesive layer of a sticker adhering to a fragile paper surface, it shaves the adhesive layer very close to and parallel to the paper surface without damaging it.

Description

United States Patent [1 1 3,818,592 Himeno June 25, 1974 154] KNIFE FOR PEELING OFF STICKERS AND FOREIGN PATENTS OR APPLICATIONS THE LIKE 660,891 11/1951 Great Britain 30/357 [75] Inventor: Shohachi Himeno, Tokyo-to, Japan 1,016,199 10/1964 Great Britain 30/346 7 C K h K T 3] Asslgneg 32?: abus [kl alsha Okyo to Primary Examiner-Al Lawrence Smith Assistant Examiner.l. C. Peters [22] Filed: May 7, 1973 Attorney, Agent, or Firm-Eric l-l. Waters [2]] Appl. No.: 358,161

[57] ABSTRACT 30 Forei n A licafi n Prior-t Data A knife has a flat reverse face and a beveled cutting 1 M 20 o 47 50025 face on the opposite side with a bevel dihedral angle l 972 Japan 47-58904 of approximately 15 and a truncated extreme cutting 3y apan edge in the form of a blunt leading edge, narrow regions respectively of the beveled cutting face and the 8 30/151 30/ 23 1 433; reverse face immediately adjacent to and extending 58 i IIIIIIII 5 357 o g the leading edge being further beveled with min- 1 0 care ll 51 5/36 ute bevel angles each of approximately 25 relative to the beveled cutting face and the reverse face. When a knife of this shape is advanced with the leading edge [56] References cued in front into the thin adhesive layer of a sticker adher- UMTED STATES PATENTS ing to a fragile paper surface, it shaves the adhesive 2,484,692 10/1949 Deluce 30/353 X layer very close to and parallel to the paper surface 2,901.823 9/1959 Widen 1 30/151 ithout damaging it 3,292,478 12/1966 Falk .4 30/357 X 0 3,492.903 2/1970 Malm 30/346 x 4 Claims, 7 a ng gures U 'J 1 2 loo Q g @717 l i PATENTEDJUNZS 1974 SHEET 1 [1F 2 KNIFE FOR PEELING OFF STICKERS AND THE LIKE BACKGROUND This invention relates generally to cutlery-like tools and more particularly to a knife for peeling or exfoliating sticking pieces such as labels seals, tapes, and the like off paper sheet surfaces, surfaces of paper containers, and the like fragile surfaces.

When such a sticking piece (hereinafter referred to as a sticker) adhering to a paper sheet surface or surface of a paper container is peeled or stripped off by conventional procedure, the underlying paper surface tends to be stripped off by the adhesive on the sticker. This results from forceful pulling off of the adhesive adhering to the paper surface from that surface.

In the case where an ordinary sticker is stuck onto a paper surface, the thickness of the adhesive layer interposed therebetween is of the order of I/ 1,000 mm. If it were possible to cut or split this adhesive layer parallelly to the paper surface and, moreover, as close as possible to the paper surface, it would be possible to peel off the sticker without damaging the paper surface.

However, with a knife of the types in general use with sharp cutting edges, it is extremely difficult to make such a cut or split in a steady manner as a spacing of less than I/ l ,000 mm. is maintained between the knife cutting edge and the paper surface, the likely result being an inadvertent cut into the paper surface.

SUMMARY In view of the above described difficulties, it is an object of this invention to provide a knife for peeling off stickers capable of cutting through the above mentioned adhesive layer parallelly and as closely as possible to the paper surface.

According to this invention in one aspect thereof, there is provided a knife for peeling off stickers and the like characterised in that it has a knife blade made of va thin, elastic strip beveled to form a beveled cutting face on only one side along at least one lateral edge thereof, the opposite reverse face being substantially flat and forming an acute bevel or dihedral angle with the beveled cutting face, the resulting dihedral intersection being truncated to form a blunt leading edge substantially perpendicular to the reverse face, very narrow regions respectively of the beveled cutting and reverse faces immediately adjacent and extending along the leading edge being further beveled with minute bevel angles.

According to this invention in a further aspect I thereof, there is provided a knife of the above stated character further characterised by the combination thereof with a handle secured to the tang of the blade and a sheath having a cavity with an entrance to accommodate the blade and having strips of a wiping material secured to the inner wall surface of the cavity from the entrance thereof inward and serving to wipe the blade as his inserted into and extracted from the cavity.

The nature, principle, and utility of this invention will be more clearly apparent from the following detailed description with respect to preferred embodiments of the invention when read in conjunction with the ac- 2 companying drawings, in which like parts are designated by like reference numerals.

DRAWINGS In the drawings:

FIG. 1 is a plan view showing one example of a knife blade according to this invention;

FIG. 2 is an enlarged, fragmentary cross section of the edge part of the knife blade;

FIG. 3 is a fragmentary cross section indicating a state of use of the knife blade;

FIG. 4 is a plan view showing another example of a knife blade according to this invention having two beveled cutting faces on the same side along respective lateral edges;

FIG. 5 is a plan view showing the exterior of a knife according to the invention having a blade in combination with a handle and a sheath;

FIG. 6 is a longitudinal section of the combination shown in FIG. 5; and

FIG. 7 is a cross section of the combination shown in FIG. 5.

DETAILED DESCRIPTION Referring first to FIGS. 1, 2, and 3, the knife blade body 1 shown therein is formed from a highly elastic material such as, for example, a carbon tool steel of a carbon content of from l.l0 to 1.30 percent, maximum silicon content of 0.35 percent, and maximum manganese content of 0.50. The blade width is of the order of 9 mm. at the tip la, 18 mm. at the base or heel lb, and 12 mm. at the tang 1c. The overall length is of the order of 200 mm. including a tang 1c length of the order of mm.

One lateral edge of the blade body 1 is beveled to form a beveled cutting face 2, which is inclined with an dihedral angle of the order of l5 relative to the plane of the flat reverse face 3 and has a width of the order of 2 mm.

A cutting or leading edge 4 constituting the extreme outer edge of the blade is in the form of a flat, cut-off or truncated surface perpendicular to the plane of the reverse face 3. This leading edge 4 is formed by cutting off approximately 1 mm. of the sharp edge of a cutting edge formed by the intersection of the plane of the reverse face 3 and the inclined plane of the beveled cutting face 2. The width of this leading edge 4 is of the order of from 0.02 to 0.03 mm.

The extreme edge regions of the beveled face 2 and the reverse face 3 adjacent to the leading edge 4 are further beveled to form narrow beveled peeling edges 5 and 6, respectively, each of a width of approximately 0.03 mm. These beveled peeling edges 5 and 6 are inclined with an inclination angle of the order of 2.5 degrees relative to the beveled cutting face 2 and the reverse face 3, respectively.

The peeling edges 5 and 6 are preferably satin finished or hairline finished in the direction perpendicular to the leading edge 4 thereby to prevent sticking of adhesive thereto.

The manner in which the knife blade 1 of the above described nature peels a sticker 7 with an adhesive 9 from a piece of paper 8 is indicated in FIG. 3, in which the relative dimensions of the parts of the materials and the knife blade have been selected for clarity in illustration and differ from those in an actual case.

For this peeling operation, one edge of the sticker 7 adhering to the paper 8 is pulled slightly apart from the paper to form a minute gap therebetween. The leading edge 4 is then inserted into this gap, and the blade 1 with the edge 4 leading the way is pressed toward the peeling direction as it is caused to undergo minute back-and-forth movements in its longitudinal direction.

During this peeling action, the reverse face 3 of the blade is held flat against the paper surface. As a result, the blade 1 is bent into a curved figure with the tang 1c inclined upward toward its rear end.

As the blade 1 advances in its peeling action with the leading edge 4 in the van and the reverse face 3 held flat against the surface of the paper 8, the sticker 7 is induced to follow the blade along the beveled peeling edge 5, while the leading edge 4 at its lower edge splits or separates the adhesive layer 9 at a position close to the surface of the paper 8. It has been found that, as a result of this splitting action, the adhesive layer remaining on the paper side is of a thickness of the order of from 0.0001 to 0.0002 mm. and, therefore, is almost invisible to the naked eye.

In a modification of the example of the knife according to the invention as described above, beveled cutting faces 2, 2 are formed along both lateral edges of the blade 1 on the same side thereof as shown in FIG. 4. Each of these beveled faces 2, 2 and the related parts, that is, the leading edge 4 and the beveled peeling edges and 6, are the same in dimension, and shape as those of the preceding example, and the reverse face 3 is also flat except for the beveled peeling edges 6, 6 at its extreme lateral edge parts. In this example, also, the beveled peeling edges 5 and 6 are satin finished or hairline finished to prevent or great reduce sticking of adhesive at the time of peeling operation.

The knife blade of this invention, whether it is single edged as shown in HO. 1 or whether it is double edged as shown in FIG. 4, is rendered convenient for practical use by the provision of a handle such as a handle 10 comprising a combination of two halves 10a and 10b secured onto the opposite sides of the tang 1c of the knife blade.

In addition, a scabbard or sheath 11 is provided for insertion thereinto of the exposed part of the knife blade 1 from the tip In to the heel 1b. This sheath 11 is formed from two halves 11a and 11b secured to gether with a cavity therebetween for accommodating the blade. Beginning at the entrance of this sheath 11 and extending inward for approximately 40 percent of the length of the cavity, there are provided strips 12, 12 of a soft material processed with a silicon resin such as, for example, so-called silicone cloth, bonded respectively to the inner wall surfaces of the sheath halves 11a and 1 lb.

When the knife is not being used, the blade 1 is normally sheathed in the sheath 11. When the knife is to be used, the blade 1 is drawn out of the sheath 1!, whereupon the blade 1 is wiped clean by the silicone cloth strips 12, 12, whereby the adhesive such as that in the adhesive layer 9 is prevented from adhering to the blade 1 when it advances through the adhesive layer.

Thus, the knife according to this invention is capable of peeling stickers and the like sticking to paper and other fragile surfaces off these surfaces very easily and in a clean manner without damaging the underlying surfaces.

I claim:

1. A knife for peeling off stickers and the like, comprising a knife blade body (1) made of a thin strip of an elastic material and having a tang (1c) and a cutting blade (la, lb) beveled to form a beveled cutting face (2) on only one side along at least one lateral edge thereof, the opposite reverse face (3) being substantially flat and forming an acute dihedral angle with the beveled cutting face, the resulting dihedral intersection being truncated to form a blunt leading edge (4) substantially perpendicular to the reverse face, very narrow regions respectively of the beveled cutting face and the reverse face immediately adjacent to and extending along the leading edge being further beveled with minute bevel angles to form respective beveled peeling edges (5) (6).

2. A knife as claimed in claim 1 in which: said dihedral angle is of the order of 15; each of said minute bevel angles respectively relative to the beveled cutting face (2) and the reverse face (3) is of the order of 2.5 degrees; the beveled cutting face (2) has a width of the order of 2 mm. for an average width of the cutting blade of the order of 13.5 mm.; each of said beveled peeling edges (5) (6) has a width of the order of 0.03; and the leading edge (4) has a width of the order of from 0.02 to 0.03 mm.

3. A knife as claimed in claim 2 in which said elastic material is a steel of a carbon content of the order of l .20'percent.

4. A knife as claimed in claim 1 which further comprises, in combination therewith, a handle 10 secured to the tang 1c and a sheath 11 having a cavity with an entrance to accommodate the cutting blade and having strips of a silicone cloth secured to the inner wall surface of the cavity from the entrance thereof inward and serving to wipe the cutting blade as it is inserted into and drawn out from the cavity.

Claims (4)

1. A knife for peeling off stickers and the like, comprising a knife blade body (1) made of a thin strip of an elastic material and having a tang (1c) and a cutting blade (1a, 1b) beveled to form a beveled cutting face (2) on only one side along at least one lateral edge thereof, the opposite reverse face (3) being substantially flat and forming an acute dihedral angle with the beveled cutting face, the resulting dihedral intersection being truncated to form a blunt leading edge (4) substantially perpendicular to the reverse face, very narrow regions respectively of the beveled cutting face and the reverse face immediately adjacent to and extending along the leading edge being further beveled with minute bevel angles to form respective beveled peeling edges (5) (6).

2. A knife as claimed in claim 1 in which: said dihedral angle is of the order of 15*; each of said miNute bevel angles respectively relative to the beveled cutting face (2) and the reverse face (3) is of the order of 2.5 degrees; the beveled cutting face (2) has a width of the order of 2 mm. for an average width of the cutting blade of the order of 13.5 mm.; each of said beveled peeling edges (5) (6) has a width of the order of 0.03; and the leading edge (4) has a width of the order of from 0.02 to 0.03 mm.

3. A knife as claimed in claim 2 in which said elastic material is a steel of a carbon content of the order of 1.20 percent.

4. A knife as claimed in claim 1 which further comprises, in combination therewith, a handle 10 secured to the tang 1c and a sheath 11 having a cavity with an entrance to accommodate the cutting blade and having strips of a silicone cloth secured to the inner wall surface of the cavity from the entrance thereof inward and serving to wipe the cutting blade as it is inserted into and drawn out from the cavity.

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