Cutting instrument and method for producing same

Abstract

The present invention relates to a one-piece cutting instrument (1) having an integral fixed blade, the cutting instrument comprising a one-piece, integral body (2) in the shape of an ellipsoid comprising an equatorial plane of symmetry E, a meridian plane of symmetry M and a polar plane of symmetry P, the body (2) comprising a truncated ellipsoid portion (2e) forming an asymmetric blade (3), the blade (3) comprising a first planar surface (5) forming a plane L, which is the truncated plane of the truncated ellipsoid portion (2e), and a second surface (6) which is convex. The invention also relates to a cutting instrument assembly (1) or to a kit, as well as to a method for producing the cutting instrument (1).

Description

SHARP INSTRUMENT AND METHOD OF OBTAINING IT

[0001] The present invention relates to a one-piece cutting instrument, and to a method of obtaining such a cutting instrument. State of the art

[0002] Cutting instruments, such as knives, machetes, and sabers, come in a wide variety of shapes, sizes, and uses. They can be used as cooking utensils, butchering tools, hunting tools, utility tools, or even as combat or sporting weapons.

[0003] Cutting instruments, and more specifically knives, are generally divided into two broad categories: so-called "straight" instruments, those with a fixed blade, and so-called "closing" instruments, folding or retractable, those with a blade that moves relative to the handle.

[0004] Conventionally, a straight-edged instrument, for example a knife, is not generally made of a single piece or in one piece. It comprises two separate elements, fixed to each other in an irremovable manner, namely: a body, a first portion of which constitutes the blade, and a second portion of which constitutes the tang, and a handle or elements of a handle, which are fixed to the tang, by embedding, by gluing or by the use of screws or rivets.

[0005] The blade can take on different shapes and have different dimensions, which are generally adapted to the final destination, the final use of the cutting instrument.

[0006] Generally, the blade consists of a back, and a grind, the end of which forms the cutting edge, which can be smooth, serrated, or mixed, namely with a smooth part and a serrated part.

[0007] Usually, the blade is flat and symmetrical. It extends from the handle in continuity with the plane of symmetry of the handle, in other words it extends in the plane of symmetry of the handle.

[0008] The blade generally has two faces which are symmetrical and have the same profile. The blade can have a V shape, a biconcave shape or biconvex. However, the blade can also be asymmetrical, its faces not having the same profile; it can include, for example, a so-called "chisel" grind.

[0009] For example, document FR3080312 describes a straight or closing knife, comprising an oval or ovoid blade, the two faces of which are symmetrical and flat, extending in the continuity of the plane forming the tang, which receives plates forming a handle in the shape of a rugby ball.

[0010] The cutting instrument can usually be accompanied and slipped into a protective cover or sheath, in order to protect the tip and the cutting edge of the blade.

[0011] A straight-edged instrument is usually obtained through a long and complex manufacturing process, involving many steps.

[0012] First, the blade and tang are formed to the desired profile, shape, and dimensions, usually by forging one or more metals or metal alloys, cutting a metal plate, or pressure forming a powdered ceramic material, before the grind is shaped. The process also includes one or more hardening steps to strengthen the blade, possibly a tempering step, a final grind step, a polishing step, possibly marking, making the handle, attaching it to the tang and shaping and finishing it, and finally a sharpening step to form the cutting edge. Aims of the invention

[0013] The present invention aims to provide a cutting instrument, a cutting instrument assembly or kit, and a method for obtaining such a cutting instrument, which do not have the drawbacks of the state of the art.

[0014] The present invention aims to provide an alternative to existing state-of-the-art solutions.

[0015] The present invention aims to provide a cutting instrument, for example a razor, a knife, a machete or a saber, which has an optimized grip, a blade with an improved and progressive cutting edge, a blade also having improved strength and rigidity.

[0016] The present invention aims to provide a method of producing a cutting instrument, for example a razor, a knife, a machete or a saber which is easy, quick and inexpensive to implement. Summary of the invention

[0017] The present invention relates to a single-piece, fixed-blade cutting instrument comprising a single-piece, single-piece body having the shape of an ellipsoid comprising an equatorial plane of symmetry E, a meridian plane of symmetry M and a polar plane of symmetry P, the body comprising a truncated ellipsoid portion and which forms an asymmetrical blade, the blade comprising a first planar surface, forming a plane L, which is the truncation plane of the truncated ellipsoid portion, and a second surface (6) which is convex.

[0018] According to preferred embodiments of the invention, the cutting instrument according to the invention comprises at least one, or any suitable combination, of the following features: - the blade comprises a cutting edge, formed by the intersection between the first surface and the second surface, which is convex, - the cutting edge is progressive, - the plane L of the blade is oblique to the equatorial plane E of the ellipsoid, - the plane L of the blade is oblique to the equatorial plane E of the ellipsoid and oblique to the meridian plane M and / or the polar plane P, - the surface of the blade has the shape of a portion of an ellipse in the plane L and includes a rim, - the body has the shape of an elongated or oblong ellipsoid, - the cutting instrument is a kitchen utensil or a manual cutting or chopping tool, a razor, a knife, a machete or a sabre,

[0019] The present invention further relates to a cutting instrument assembly, or a kit, comprising the cutting instrument according to the invention, and means for protecting the blade of the cutting instrument, which are assembled, or not, to the cutting instrument.

[0020] In a particular embodiment of the assembly, or kit, the blade protection means comprise, or are, an ellipsoid element, having a shape and dimensions complementary to the portion of the truncated ellipsoid, in order to form, once associated with the cutting instrument, a non-truncated ellipsoid.

[0021] The present invention also relates to a method for producing the cutting instrument according to the invention, comprising a step of taking, or producing, a single-piece body, made from a single piece, having the shape of an ellipsoid comprising a portion of ellipsoid which is truncated, or the steps of taking, or producing a single-piece body element, made from a single piece, having the shape of an ellipsoid and producing a truncation of the ellipsoid, to obtain a portion of ellipsoid which is truncated, the truncated portion of ellipsoid forming an asymmetric blade, comprising a first flat surface, forming a plane L, which is the truncation plane of the truncated portion of ellipsoid, and a second surface which is convex.

[0022] According to preferred embodiments of the invention, the method according to the invention comprises at least one, or any suitable combination, of the following features: - the truncated ellipsoid portion is obtained by truncation means which are, include, or implement, cutting by a LASER beam, or abrasion using one or more abrasive tools - the body is made by molding a material or mixture of materials, - the method further comprises preliminary steps of determining the dimensions and shape of the ellipsoid of the body and of determining the position and orientation of the plane L of truncation of the ellipsoid, - the preliminary steps are implemented using software and IT resources. Brief description of the figures

[0023] Figure 1 is a schematic representation of a perspective view of an ellipsoid.

[0024] Figure 2 is a schematic representation of a front view of an ellipsoid on which these three cutting planes are indicated.

[0025] Figure 3 is a schematic representation of a perspective view of a first embodiment of the cutting instrument according to the invention.

[0026] Figure 4 is a schematic representation of a side view of the embodiment of the cutting instrument shown in Figure 3.

[0027] Figure 5 is a schematic perspective representation of the cutting plane forming the blade of the embodiment of the cutting instrument shown in Figure 3.

[0028] Figure 6 is a schematic representation of a front view, blade side, of the embodiment of the cutting instrument shown in Figure 3.

[0029] Figure 7 is a schematic representation of a side view of the cutting edge of the embodiment of the cutting instrument shown in Figure 3.

[0030] Figure 8 is a schematic representation of a perspective view of the means used to produce the blade of the embodiment of the cutting instrument shown in Figure 3.

[0031] Figure 9 is a schematic representation of a perspective view of an embodiment of the blade of the embodiment of the cutting instrument shown in Figure 3.

[0032] Figure 10 is a schematic representation of a perspective view of a second embodiment of the cutting instrument according to the invention.

[0033] Figure 11 is a schematic representation of a front view, blade side, of the embodiment of the cutting instrument shown in Figure 10.

[0034] Figure 12 is a schematic representation of a perspective view of one embodiment of the method of obtaining the cutting instrument shown in Figure 10.

[0035] Figure 13 is a schematic representation of a perspective view of a third embodiment of the cutting instrument according to the invention.

[0036] Figure 14 is a schematic representation of a view of a detail of the embodiment of the cutting instrument shown in Figure 13.

[0037] Figure 15 is a schematic representation of a perspective view of a fourth embodiment of the cutting instrument according to the invention.

[0038] Figure 16 is a schematic representation of a perspective view of one embodiment of the method of obtaining the cutting instrument shown in Figure 15.

[0039] Figure 17 is a schematic representation of a perspective view of the embodiment of the cutting instrument shown in Figure 3 with blade protection means. Detailed description of the invention

[0040] In the remainder of the description and the claims, the cutting instrument 1 according to the invention is defined according to a spatial reference frame XYZ, as shown in Figures 1 to 17. The term "length" is used to describe the dimension along the X-X' axis, the term "width" to describe the dimension along the Z-Z' axis, and the term "thickness" to describe the dimension along the Y-Y' axis. Furthermore, the term "substantially" is used, in the present description, to indicate a general orientation of the constituent elements of the cutting instrument 1 relative to each other or relative to the spatial reference frame.

[0041] The cutting instrument 1 according to the present invention is a manual cutting or dicing instrument or tool, which is called "straight". It is a fixed-blade cutting instrument, not having handle elements, or a handle, fixed on a tang, because it does not have a tang.

[0042] The cutting instrument 1 comprises a one-piece body 2, made from a single piece. It can be solid and not hollow, which has the advantage of increased strength, or it can be hollow, or partially hollow, which has the advantage of being lighter.

[0043] Body 2 has the shape of a truncated ellipsoid.

[0044] An ellipsoid, or ellipsoid of revolution, is defined by a radius "a", or major equatorial radius, also called the semi-major axis, a radius "b", or minor equatorial radius, also called the semi-minor axis, and a radius "c", or polar radius, (figure 1). The ellipsoid has a first plane of symmetry, extending along the major axis, the equatorial plane E, parallel to the XZ plane, a second plane of symmetry, the meridian plane M, parallel to the YZ plane, and a third plane, the polar plane P, parallel to the XY plane (figure 2). The ellipsoid defines two hemispheres, a northern hemisphere and a southern hemisphere, and eight sectors of identical volume, each hemisphere comprising two sets of two lateral sectors, which are also end sectors. The term "truncated ellipsoid" means an ellipsoid of which one hemisphere, or a portion of a hemisphere, or of which at least one or more sectors, preference of two sectors, advantageously of three sectors, is or are missing.

[0045] The body 2 of the cutting instrument 1 has a radius b and a radius c which are, independently of each other, less than the radius a. Preferably, the radius b is equal to the radius c, the body 2 then adopts the shape of an elongated ellipsoid, or oblong. Advantageously, the radius c is less than the radius b, which has the advantage of providing easier handling.

[0046] The body 2 has dimensions, a length, a width and a thickness, therefore radii a, b and c, which are chosen according to, and whose relationship to each other depends on, the cutting instrument 1, its nature, razor, knife, machete or saber for example, its final use and its final user. For example, the equatorial radius, radius a, can be about 12 cm for a kitchen utensil, for example a knife, and about 17 cm for a weapon, for example a saber.

[0047] The ellipsoid shape of the body 2, and therefore of the cutting instrument 1, has the advantage of having optimized ergonomics, of allowing its grip to be optimized by the fingers of one hand, for example for a knife, or its grip in the hand and palm, for example for a saber, by varying the ratio between the different radii a, b and c.

[0048] The body 2 of the cutting instrument 1 comprises a first extreme edge 2a and a second extreme edge 2b, opposite the first extreme edge 2a with respect to the meridian plane M, a first lateral edge 2c and a second lateral edge 2d opposite the first lateral edge 2c with respect to the polar plane P (figures 3 and 4).

[0049] The body 2 comprises a first portion 2e of its length, which forms a blade 3, and a second portion 2f of its length, which forms a gripping portion, namely a handle 4. The handle 4 comprises, or is made of, the portion(s) of the body 2 which is or are not the blade 3 (figure 4).

[0050] The length of the blade 3 and that of the handle 4 may be identical or equivalent; however, in other embodiments, they may be different.

[0051] Blade 3 is formed by the truncation of the ellipsoid forming body 2. It is formed by the section plane, or cutting plane, or truncation plane, of the ellipsoid, a portion of the ellipsoid, a portion of a hemisphere, a portion of the northern hemisphere (figure 5).

[0052] The blade 3 comprises a first surface 5, which is the surface of the portion of the ellipsoid that has been hollowed out; it is substantially flat, uniform, and forms a plane L, which also constitutes a grind. The plane L is the cutting, truncation plane of the ellipsoid of the body 2. In this plane L, the blade 3 has the shape of an ellipse or a portion of an ellipse.

[0053] The plane L is an oblique plane at least relative to the equatorial plane E of the body 2. The plane L is neither parallel nor perpendicular to the equatorial plane E, but adopts an intermediate position between these two extreme positions. It can form, with the equatorial plane E, an angle greater than 5 degrees and less than 30 degrees.

[0054] Preferably, the plane L is oblique to the equatorial plane E, but also oblique to the meridian plane M and / or the polar plane P.

[0055] In a particular embodiment, the plane L is oblique to the equatorial plane E by an angle of approximately 30°, oblique to the meridian plane M by an angle of approximately 80° and oblique to the polar plane P by an angle of approximately 45°.

[0056] The angle formed by the plane L with the equatorial plane E, and possibly those formed with the meridian planes M and / or polar planes P, is or are determined, and depends on, the dimensions of the body 2, the blade 3, the fineness of the cutting edge 7, the nature of the cutting instrument 1, razor, knife, machete or sabre for example, its final use and its final user.

[0057] Seen from the side of the cutting instrument 1, the blade 3, and therefore its plane L, extend, preferably, along only a portion of the hemisphere (figure 4).

[0058] In this embodiment, the second portion 2f of the body 2 forming the handle 4 is a non-truncated portion of the ellipsoid, which makes gripping the cutting instrument 1 more pleasant. The handle 4 comprises, or is formed by, a portion of the northern hemisphere and the southern hemisphere (figure 4), by at least the two sectors of the first extreme edge 2a of the southern hemisphere.

[0059] Seen from the second extreme edge 2b, the blade 3, and therefore its plane L, can also extend over at least the sector of the first lateral edge 2c of the northern hemisphere or the sector of the second lateral edge 2d of the northern hemisphere, depending on whether the end user of the cutting instrument 1 is right-handed or left-handed. preferably, the blade 3, and therefore its plane L, also extend over, respectively, at least a portion of the sector of the second lateral edge 2d of the northern hemisphere or of the sector of the first lateral edge 2c, and preferably also over a portion of the first lateral edge 2c of the southern hemisphere, advantageously also over a portion of the second lateral edge 2d of the southern hemisphere (figure 6).

[0060] In another embodiment, the blade 3 can extend along the northern hemisphere of the body 2, over a portion of the body 2 larger than that of the previous embodiment, advantageously with the exception of the first extreme edge 2a and the second extreme edge 2b (figure 10).

[0061] In this embodiment, the second portion 2f forming the handle 4 comprises a part of the plane L, without this impairing the gripping of the cutting instrument 1.

[0062] Seen from the second extreme edge 2b, the blade 3, and therefore its plane L, may also extend over a portion of the sector of the first lateral edge 2c of the northern hemisphere and of the sector of the second lateral edge 2d of the northern hemisphere, and possibly also over at least a portion of the sector of the second lateral edge 2d of the southern hemisphere (figure 11). However, it is also conceivable that the blade 3 extends substantially along the two edges 2a, 2b, over all or part of the northern hemisphere and / or the southern hemisphere of the body 2, which has the advantage of obtaining a cutting instrument 1 which is ambidextrous, therefore for use by a right-handed person and a left-handed person.

[0063] The blade 3 has two sides, two faces. It comprises, in addition to the first surface 5, a second surface 6 (figures 3, 4, 6, 7, 11, 13, 15).

[0064] The blade 3 is asymmetrical, namely that the first surface 5 and the second surface 6 do not have the same profile. Preferably, it is asymmetrical over its entire length.

[0065] The second surface 6 is not ground. It is convex. This has the advantage of providing structural reinforcement to the blade 3, thus improving its properties of resistance to torsion and vibration, while giving it improved hardness and a useful mass, which naturally contributes to the support of the cut.

[0066] Whatever the embodiments, the blade 3 has the advantage of having at least one rounded tip 8, which has the advantage of being less fragile in the event of a fall.

[0067] The cutting edge 7 is formed by the intersection of the first flat surface 5 and the second convex surface 6. It is located at the intersection between the plane L and the second convex surface 6 of the blade. It is located at the portion of the ellipsoid at which the angle or angles between the plane L and the convex surface 6 are the sharpest. It extends over at least a portion of a lateral edge 2c or 2d of the body 2 (figures 3, 10 and 13).

[0068] The cutting edge 7 extends over at least a portion of a lateral edge 2c or 2d of the body 2. It is formed by the intersection of the first flat surface 5 and the second convex surface 6. It is located at the intersection between the plane L and the second convex surface 6 of the blade. It is located at the portion of the ellipsoid at which the angle or angles, between the plane L and the convex surface 6, are the sharpest.

[0069] The blade 3 is preferably smooth along the cutting edge 7, but it is not excluded that it could be toothed, or partially toothed, therefore mixed.

[0070] In a particular embodiment of the invention, the teeth may be located on the second surface 6 of the blade 3.

[0071] The cutting edge 7 of the blade is progressive (figure 7), that is to say that it flares from the second extreme edge 2b, towards the first extreme edge 2a.

[0072] Preferably, the cutting edge 7 is progressive, according to an exponential function; it has an exponential shaped profile.

[0073] For example, as shown in Figure 7, at a point A, at the tip 8 of the blade 3, or in the immediate vicinity of the tip 8, the angle a, which the surface 5 of the blade 3, and therefore the plane L, forms with the tangent, at this point, of the convex surface 6 is preferably less than 25°. Advantageously, it is approximately 15°.

[0074] For example, for a razor, at point A, the angle formed by surface 5 with the tangent, at this point, of the convex surface 6, is approximately 15°, and approximately 25° for a kitchen utensil such as a knife.

[0075] At a point B, for example at about mid-length of the blade 3, the angle P, which the surface 5 forms with the tangent, at this point, of its convex surface 6, is greater than the angle a. It is for example about 40°.

[0076] At a point C, close to the handle 5, the angle y, which the surface 5 forms with the tangent, at this point, of its convex surface 6 is greater than the angle (3. It is for example approximately 120°.

[0077] The progressive cutting edge 7 has the advantage of having a blade 3 which is very sharp at its tip 8 and less sharp as the edge approaches the handle 4.

[0078] This has the advantage of having a cutting instrument 1 whose handle 4 is a truncated or partially truncated portion of the ellipsoid, the angle between the first flat surface 5 and the second convex surface 6 not being sharp, but greater than 100°.

[0079] The blade 3, and therefore the cutting instrument 1, have the advantage of having improved strength, rigidity and weight compared to a symmetrical straight blade, of having good mechanical strength, good resistance in the event of a fall, and of having a blade 3 with better cutting finesse due to a progressive cutting edge, and of allowing the blade 3, its grinding, and the cutting edge 7 to be produced concomitantly during the production of the blade 3 and therefore of the cutting instrument 1.

[0080] In particular embodiments of the invention, the cutting instrument 1 comprises a blade 3 having the shape of a portion of an ellipse. This portion of an ellipse may extend along the second lateral edge 2d (figure 14) or the first lateral edge 2c of the body, depending on whether the instrument is for a right-handed or left-handed person, or else extend substantially along the two edges 2a, 2b of the body 2 (figure 15), which has the advantage of obtaining a cutting instrument 1 which is ambidextrous.

[0081] In these embodiments, the blade 3 comprises a rim 10, at the opposite end of the tip 8, which constitutes a transition between the blade 3 and the handle 4. This rim 10 can be oblique, preferably with an orientation towards the handle 4, in the X'-Y plane (figures 13 and 14) or else be straight, with an orientation substantially perpendicular to the surface 5 of the blade 3, along the Y'-Y axis (figure 15).

[0082] Preferably, the rim 10 is, forms part of, or cooperates with, means for receiving protection means 11 of the blade 3.

[0083] Whatever the embodiments according to the invention, the body 2 of the cutting instrument 1, and therefore its handle 4 and its blade 3, comprise, or are made, preferably of one or more materials, for example glass, one or more metals or one or more metal alloys. They may comprise, or be made of, aluminum, stainless steel, a titanium alloy, tungsten carbide or zirconium oxide.

[0084] Preferably, the cutting instrument 1 according to the invention is a manual cutting or dicing tool. Advantageously, it is a razor, a knife, a machete or a saber. It is used for chopping, mincing, slicing and / or cutting all kinds of products, preferably food.

[0085] The cutting instrument assembly 12 according to the invention comprises, or is made up of, the cutting instrument 1 according to the invention, whatever the embodiment considered, associated with means 11 for protecting the blade 3 of said cutting instrument 1. This assembly 12 can also be a “kit”, namely the cutting instrument 1 and the means 11 for protecting the blade 3 not assembled to each other (figure 17).

[0086] The protection means 11 of the blade 3 are capable of, and intended to, receive, or cooperate with, the blade 3 and / or the body 2 of the cutting instrument 1, in a reversible manner.

[0087] Preferably, the protection means 11 have a complementary shape, or one capable of cooperating, with the blade 3 and / or the body 2. They may comprise or take the form of a sheath in which the blade 3 engages.

[0088] Advantageously, the protection means 11 take the form of the truncated part of the ellipsoid of the body 2. They comprise, or are, an ellipsoid element 13, having a shape and dimensions complementary to the truncated ellipsoid of the body 2, in order to form, once associated with the cutting instrument 1, a non-truncated ellipsoid. It may have the shape of an ellipsoid (figure 17), or of a portion of an ellipsoid. This gives the cutting instrument 1 an aesthetic advantage.

[0089] Preferably, the ellipsoid element 13 consists of the part, the physical element, of the ellipsoid which has been truncated.

[0090] Preferably, the protective means 11 comprise, or are made of, the material(s) from which the blade 3 is made, or are compatible with the latter.

[0091] The protection means 11 of the blade 3 are held on the body 2 or around the body 2, advantageously on the blade 3, or around the blade 3, by mechanical and / or magnetic means.

[0092] For example, the mechanical means may comprise or implement a male-female interaction, for example of the mortise-and-tenon type. The magnetic means may comprise one or more magnets, or implement the magnetization of the blade 3, with one or more magnets of the protection means or its magnetization.

[0093] Whatever their embodiments, the protection means 11 of the blade 3 can be used as a support for the cutting instrument 1, for example as a knife holder in the embodiment in which the cutting instrument 1 is a knife.

[0094] Cutting instrument 1 has the advantage of being simple to make and requiring very simple tools.

[0095] The method of producing the cutting instrument 1 comprises the step of taking, or producing, a single-piece body 2, made from a single piece having the shape of an ellipsoid, which may be solid and not hollow, or hollow or partially hollow, comprising a portion of the ellipsoid 2e which is truncated, or the steps of taking or producing a single-piece body element 14, made from a single piece having the shape of an ellipsoid, which may be solid and not hollow, or hollow or partially hollow, and of producing a truncation of the ellipsoid.

[0096] The method of producing the cutting instrument 1 according to the invention has the advantage of being easier to implement, requiring a reduced number of steps, thanks to the shape of the body 2 and that of the blade 3. In particular, it does not require the production of a tang, and therefore the fixing of elements to form a handle, and does not require the production of a grinding on the two faces of the blade.

[0097] In any event, due to the shape and construction of the blade 3, a step of forming the cutting edge 7 and sharpening the blade is not necessary, the construction of the cutting edge 7 being carried out during the construction of the blade 3.

[0098] Preferably, the body element 14, or the truncated body 2, are made by 3D printing, molding, die casting, forging, injection, MIM injection, or pressing and cutting, of a material or mixture of materials.

[0099] In the embodiments comprising the use of a mold, the method according to the invention may comprise a prior step of producing the mold, or parts of the mold, or cavity, adapted to, and capable of, obtaining a single-piece body element 14, made from a single piece, having the shape of an ellipsoid, or the body 2, having the shape of a truncated ellipsoid, and advantageously a prior step of determining the shape and dimensions of the cutting instrument 1, of the ellipsoid, in particular these radii a, b, c, and possibly also the size and orientation of the blade 3, in particular the orientation of the plane L of the blade 3 relative to the equatorial plane E, the meridian plane M and the polar plane P.

[0100] In these embodiments, the method comprises the step of melting a material or set of materials, casting this or these materials into the mold, then cooling and demolding the one-piece body element 14 or the body 2 of the cutting instrument 1.

[0101] Preferably, the step of truncating the ellipsoid is carried out using truncation means 15, capable of cutting or abrasion of one or more materials. This step can be carried out by cutting an entire block of the ellipsoid, which can then form the ellipsoid element 13 of the protection means 11 of the blade, the cutting means 15, comprising, or being, for example, a LASER beam, or by mechanical or chemical abrasion of successive layers of the material(s) of the body element 14, the cutting means 15, comprising or being, one or more abrasive tools, for example, a grinding wheel 16.

[0102] In embodiments employing a grinding wheel 16, the latter is made of, or comprises, a material or an assembly of materials, compatible with the material(s) of the body element 14, capable of abrading the latter, thus removing material.

[0103] The grinding wheel 16 may adopt the shape of a cylinder comprising a lower abrasion surface 17, preferably substantially planar, and which is oriented relative to the body element 14, so as to form the truncation plane L, such that described previously. It may further comprise a lower edge 18, on the periphery of the lower abrasion surface 17, which may be chamfered (figure 8) or straight (figures 9, 12 and 16). This has the advantage of being able to obtain a blade 3 having the shape of an ellipse, or the shape of a portion of an ellipse and therefore a blade 3 having an edge 10, which may be oblique or straight.

[0104] The method according to the invention may further comprise steps prior to the formation of the body 2, or of the body element 14, which may comprise, or consist of, determining the dimensions and therefore the shape of the ellipsoid, for example determining the lengths of the radii a, b, c of the ellipsoid and their ratio to each other, determining the cutting or truncation plane of the ellipsoid, for example its position relative to one of the hemispheres, preferably both hemispheres of the body 2, its orientation relative to the equatorial plane E, the meridian plane M and the polar plane P. Preferably, these steps are carried out as a function of the nature and / or the destination of the cutting instrument 1 according to the invention and / or its end user. This has the advantage of being able to optimize the ergonomics and the grip of the cutting instrument 1.Preferably, all or part of these steps are carried out by modeling, advantageously using software and computer means, which has the advantage of having increased design flexibility.

[0105] The method according to the invention may further comprise steps of deburring and / or shot blasting and / or polishing, for example chemical-mechanical polishing or tribofinishing and / or grinding and / or reinforcing the blade, and possibly a step for partially or totally serrating the cutting edge 7.

[0106] In embodiments in which the material from which the cutting instrument 1 is made is steel, the method may comprise a step of polishing the body 2 and / or the blade 3 and / or a step of quenching and annealing in order to increase the hardness of the cutting instrument 1, in particular of the blade 3, preferably up to a value of between about 50 and about 60 Rockwell.

[0107] The method of producing the cutting instrument assembly 12, or the kit, comprises implementing the method of producing the cutting instrument 1 according to the invention, and a step of taking, or producing, protection means 11 of the blade 3, capable of, and intended to, receive, or cooperate with, the blade 3 and / or the body 2 of the cutting instrument 1.

[0108] Preferably, the method for producing the protection means 11 of the blade 3 comprises, or implements, steps and / or successions of steps, identical or equivalent, to those implemented for producing the body 2, or the body element 14, of cutting instruments 1. Advantageously, it implements a LASER ablation of the body element 14 to form the ellipsoid element 13.

Claims

DEMANDS 1. Cutting instrument (1) with a fixed blade, monobloc, in one piece, comprising a monobloc body (2) in one piece, having the shape of an ellipsoid comprising an equatorial plane of symmetry E, a meridian plane of symmetry M and a polar plane of symmetry P, said body (2) comprising a portion of the ellipsoid (2e) which is truncated and which forms an asymmetrical blade (3), said blade (3) comprising a first flat surface (5), forming a plane L, which is the truncation plane of said truncated portion of the ellipsoid (2e), and a second surface (6) which is convex.

2. The cutting instrument (1) according to claim 1, in which the blade (3) comprises a cutting edge (7), formed by the intersection between the first flat surface (5) and the second convex surface (6).

3. The cutting instrument (1) according to claim 2, in which the cutting edge (7) is progressive.

4. The cutting instrument (1) according to any one of the preceding claims, wherein the plane L of the blade (3) is oblique, at least with respect to the equatorial plane E of the ellipsoid.

5. The cutting instrument (1) according to any one of the preceding claims, wherein the plane L of the blade (3) is oblique with respect to the equatorial plane E of the ellipsoid, and oblique with respect to the meridian plane M and / or the polar plane P.

6. The cutting instrument (1) according to any one of the preceding claims, wherein the surface (5) of the blade (3) has the shape of a portion of an ellipse in the plane L and includes a rim (10).

7. The cutting instrument (1) according to any one of the preceding claims, wherein the body (2) has the shape of an elongated or oblong ellipsoid.

8. The cutting instrument (1) according to any one of the preceding claims, being a kitchen utensil or a hand tool for cutting or slicing, a razor, a knife, a machete or a saber.

9. Cutting instrument assembly (12), or kit, comprising the cutting instrument (1) according to any one of claims 1 to 8, and protective means (11) of the blade (3) of said cutting instrument (1), which are assembled, or not, to said cutting instrument (1).

10. Assembly (12), or kit, according to claim 9, wherein the means for protecting (11) the blade (3) comprise, or are, an ellipsoid element (13), having a shape and dimensions complementary to the truncated portion of the ellipsoid (2e), so as to form, once associated with the cutting instrument (1), an untruncated ellipsoid.

11. Method of making the cutting instrument (1) according to any one of claims 1 to 8, comprising the step of taking, or making, a one-piece body (2) made in one piece, having the shape of an ellipsoid comprising a portion of ellipsoid (2e) which is truncated, or the steps of taking, or making, a one-piece body element (14) made in one piece, having the shape of an ellipsoid and making a truncation of said ellipsoid, to obtain a portion of ellipsoid (2e) which is truncated, said portion of ellipsoid (2e) forming an asymmetrical blade (3), comprising a first flat surface (5), forming a plane L, which is the truncation plane of said truncated portion of ellipsoid (2e), and a second surface (6) which is convex.

12. The method according to claim 11, wherein the truncated portion of ellipsoid (2e) is obtained by truncation means (15) which are, include, or implement laser beam cutting, or abrasion using one or more abrasive tools.

13. The method according to any one of claims 11 or 12, wherein the body (2) or the body element (14) are made by molding from a material or mixture of materials.

14. The method according to any one of claims 11 to 13, further comprising prior steps of determining the dimensions and shape of the ellipsoid of the body (2) and of determining the position and orientation of the truncation plane L of the ellipsoid.

15. The method according to claim 14, wherein the preliminary steps are implemented using software and computer means.

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