The disclosure relates to finishing metallic and non-metallic surfaces by abrasion techniques.
The literature is replete with descriptions of apparatuses and methods for finishing the surfaces of a variety of articles of manufacture. Representative of such articles are tools and instruments, many having complex geometric shapes and curvilinear surfaces.
One of the problems in finishing complex surfaces, especially curvilinear surfaces, is the need to draw the article across an abrasive surface while continuously changing the angle so as to accommodate the geometric shape thereof. The finishing of complex surfaces usually requires skilled hands and experienced craftspeople. Even experts find it difficult to follow many complex surface shapes, due to the demanding control required.
In the manufacturing industry, establishing conditions for a finishing process to obtain a specified surface topography is also not problem free, since many interacting factors are involved. Under ideal circumstances, the factors to be considered involve the operational setting of the machine (e.g., the geometric characteristics of the abrasive tool, the work speed, the tool feed rate and the type of cutting fluid used). Even under ideal conditions it has been only possible to calculate the theoretical roughness developed in a machining operation for the simplest process, i.e., single-point tool cutting. The fact that it is not possible to fully specify the character and surface roughness scale and topography of a surface remains a serious problem for production/design engineers.
Disclosed is an apparatus for finishing a zone on the surface of a bladed article of manufacture, said surface comprising a plurality of adjacent and contiguous zones, comprising a support for a rigid abrasive surface; one or more channels supported on the support, each of the channels having a cross-sectional profile including at least one finishing area to finish an operative zone of the article that optimizes a clearance portion of the article, wherein the finishing areas includes a contacting area and a non-contacting area, and wherein an angle of each finishing area of the cross-sectional profile is substantively the same as an optimal clearance angle of the article, wherein the apparatus is configured to position the operable zone of the article along the angle of the finishing area during sharpening.
In certain embodiments, each of the channels includes a pair of the finishing areas. The abrasive surface can further comprise a relief connecting the pair of sharpening areas and being positioned below the pair of sharpening areas, the relief corresponding to the zone or zones to remain unfinished. A finishing area can be a linear surface or curvilinear surface.
In certain embodiments, the clearance angle β of the article is calculated as β=90°−γ−α, where α is rake angle and γ is blade angle.
In some embodiments, the support can be a block. In some embodiments, the abrasive surface comprises aluminum oxide. The support and the abrasive surface can comprise the same materials. In other embodiments, the support and the abrasive surface comprise different materials. The abrasive surface can be an exposed surface of the support. The finishing areas of the apparatus can be configured to finish a bladed article of manufacture selected from the group of: medical devices, kitchen knives, mower blades, dental curets, orthopedic curets, neurosurgical curets, ice skates, scissors (including, for example, hairdresser's scissors, surgical scissors, garden scissors, etc.) and wood planing instruments.
Disclosed is a method for finishing a zone on the surface of a bladed article of manufacture, said surface comprising a plurality of adjacent and contiguous zones, comprising: positioning an operable zone of the article in one channel on a support for a rigid abrasive surface of the article; and drawing the article through the channel, wherein one or more channels are supported on the support, each of the channels having a cross-sectional profile including at least one finishing area to finish an operative zone of the article that optimizes a clearance portion of the article, wherein the finishing areas includes a contacting area and a non-contacting area, and wherein an angle of each finishing area of the cross-sectional profile is substantively the same as an optimal clearance angle of the article, wherein the apparatus is configured to position the operable zone of the article along the angle of the finishing area during sharpening and shaping.
It is to be understood that the figures and descriptions of embodiments of the disclosure have been simplified to illustrate elements that are relevant for a clear understanding of the present invention, while eliminating, for purposes of clarity, many other elements that are conventional in this art. Those of ordinary skill in the art will recognize that other elements are desirable for implementing the present invention. However, because such elements are well known in the art, and because they do not facilitate a better understanding of the present invention, a discussion of such elements is not provided herein.
Described is an apparatus that accurately provides an exactly shaped cutting edge to a bladed instrument. The apparatus not only provides an exact shape for the bladed instrument's cutting edge, but it does so with precision every time. Described herein are embodiments for a finishing apparatus and finishing process for shaping, sharpening, and surface roughness control for bladed instruments. Bladed instruments include, without limitation, medical instruments (e.g., curets such as dental, orthopedic, or neurosurgical curets), kitchen knives, lawn mower blades, ice skates, saws, screws, wood gouges, and wood planing instruments.
In certain embodiments, the finishing apparatus is configured such that drawing the instrument, a dental curet for example, across an abrasive surface of the apparatus eased. Although the instrument itself is generally held at certain angles with respect to the abrasive surface, even this is not critical. The apparatus has one or more specifically shaped abrasive surfaces to guide and finish the instrument surface. These abrasive surfaces create an exact shape for the cutting edge of the curet. The shape provides the fineness and delicacy of its original design. Therefore, the abrasive surface component of the apparatus creates not only an exact shape of the desired cutting edge of a curet, but a cutting edge with the proper edge fineness and delicacy required in dentistry based on current research.
In embodiments, the finishing apparatus is configured to include a honing guide to draw the instrument at a correct angle with respect to the abrasive surface. As noted above, the apparatus can have one or more specifically shaped abrasive surfaces to guide and finish the instrument surface. In another embodiment, the guide can be a separate element or feature, which may or may not be adjustable, to guide a bladed instrument at a predetermined angle, as for example where the angle for a given tool (e.g. curet, scissors, etc.) is known.
One aspect relates to the finishing of surfaces on tools and instruments. For example, dental, veterinary and medical instruments may have sophisticated shapes that can only be obtained with an exacting and complex finishing procedure. Although described using a dental curet as an example, embodiments, however, are not limited to the finishing of tools and instruments for use in the medical, dental and veterinary arts. Embodiments as described herein reflect the discovery that many surfaces can be carefully finished, shaped or sharpened to obtain the objectives required. This may be carried out by placing them in contact with abrasive surfaces that mirror completely, or partially and selectively, the desired surfaces of the objects to be finished. The present innovations will aid in achieving the objectives of a specified manufacturing process (for example, surface topography or surface geometry, cross-sectional geometry, and surface finishing) by providing an apparatus having abrasive surfacing contours that have selectively planned abrading contact areas and relief surfaces (non-contacting areas) to permit a desired outcome of a finishing process. By controlled movements of the tool or instrument, or part thereof through the apparatus, one can impart a specific finish such as shaping, grinding, polishing, cleaning, buffing or sharpening to selected surface zones, while leaving other zones unfinished.
In some embodiments, a single tool may be configured to sharpen multiple different bladed instruments by configuring a single finishing apparatus and finishing process with surface topography or surface geometry, cross-sectional geometry, and surface finishing for shaping, sharpening, and surface roughness control for a plurality of bladed instruments (e.g., one area for a dental curet, one area for a scaler, one area for surgical scissors, etc.).
Those ordinarily skilled in the art will gain an appreciation of the innovations described herein from a reading of the following description of the embodiments viewed with the drawings of the accompanying
Described herein are embodiments for a finishing apparatus and finishing process for shaping, sharpening, and surface roughness control for one or more bladed instruments. Bladed instruments include, without limitation, medical instruments, kitchen knives, lawn mower blades, orthopedic curettes, neurosurgical curettes, ice skates, scissors, saws, screws, gouges, and wood planing instruments.
In the dental, veterinary and medical arts, sharp, well maintained, and properly shaped instruments provide better performance. This is universally true regarding each and every medical, veterinary, or dental instrument having a cutting or probing edge. Embodiments described herein are advantageous for use in finishing cutting surfaces of medical, veterinary, and dental instruments. For example, dental scaling instruments, some of which have long, curved cutting edges, such as curets, need to be sharpened frequently in order to function for proper tooth and root scaling in the efficacious removal of bacterial plaque, calculus (tartar deposits), and necrotic and/or diseased cementum from the surfaces of teeth crowns and their roots. The sharpening of the curved edge of the scaling tool produces a scaling surface that more readily and easily removes scale from a tooth, and also, the creation of the smoothest possible surface and shape of the treated tooth root defined in the dental literature as root planing. Scale removal can be improved by a controlled finishing of a tool with refined cutting edges; scale removal can also be accomplished with the exertion of less pressure. Such finishing also results in providing a dentist or technician with an increase in tactile sensitivity, dexterity, and control of the instrument. These instruments are placed below the gingiva and especially between adjacent tooth surfaces and when out of visual contact, there is a required dependency on increased tactile sensitivity for their use.
Likewise, reshaping and refinishing implant surfaces to restore, improve, or change their original three-dimensional topography and surface roughness can be improved by controlled finishing and refinishing of implant surfaces in vivo with a tool that has been sharpened or shaped according to the instant disclosure. Among other things, this is important because, for example, unlike the epithelia that line the oral cavity and provide an efficient defense mechanism against microbial growth due to their fast turnover (shedding three times per day), implants and other medical devices with non-shedding surfaces serve as a platform for the uncontrolled accumulation and/or metabolism of bacteria resulting in the development of a biofilm. Biofilm formation can lead to dental caries, gingivitis, periodontitis, peri-implantitis, and stomatitis. (See Teughels, W et al. Clin Oral Implants Res (2006) 17 Suppl 2: 68-81.) Therefore, instruments capable of more effectively preventing and controlling biofilm formation on implants and other medical devices with non-shedding surfaces are needed. Accordingly, in certain embodiments, the sharpening and finishing of a tool by use of an apparatus as described herein enables the reshaping and refinishing of a medical device surface to a smoothness that is less hospitable to microbial growth. For example, the subgingival environment better enables the survival of microorganisms, but a smoother surface on a dental tooth root or implant serves to minimize plaque formation and reduce the development of caries and periodontitis. (See Quirynen, M and Bollen, C M J Clin Periodontol (1995) 22(1):1-14.)
In some circumstances, the surface roughness of a natural tooth or dental implant or other device renders it conducive for the selective growth of certain biofilms. Similarly, in certain instances, the surface roughness of a dental implant or other device can promote healthy tissues or cellular growth, such as bone cells. Accordingly, in certain embodiments, an apparatus of the instant disclosure sharpens, shapes, and finishes a bladed article of manufacture to a desired roughness or smoothness at the cutting edge of the article such that it imparts a specified surface roughness to an object, such as a dental implant or natural tooth, to be finished by the article. In some embodiments, the article imparts a specified surface roughness to an object to allow for substances such as paints, adhesives, or other compounds that require certain roughness levels (e.g., in microns) to attach to the object.
Dental scalers are usually sharpened and shaped on a flat stone with a repeated reciprocal stroking, in a fashion that is similar to sharpening a knife blade. The difference, however, between the procedure of sharpening a knife blade and that of sharpening and shaping a dental scaling instrument is the degree of exercised control required in order to produce the optimum, i.e., the proper surface finish. In providing a keen edge for a curet, the exact angle at which the instrument contacts the sharpening stone is critical. For purposes of this description, the word “curet” is used to refer to all medical and dental instruments in the class, including, but not limited to, curets or “curettes,” scalers, hoes, files, sickles, explorers, and the like. As will be appreciated, any tools requiring precision sharpening and shaping can also be sharpened and shaped using embodiments of the disclosure so configured, including knives, scissors, hoes, files, and so on without limitation.
Clearance is the space between a substrate and the side of a blade or other instrument immediately behind the cutting edge of the instrument when it is in function against the substrate. The two surfaces involved, namely, the substrate and the instrument side behind the cutting edge of the instrument, form an angle measured in degrees. This angle is known as the clearance angle. (See also, e.g., Paquette, O E and Levin, M P J Periodontol (1977) 48(3):163-168, incorporated herein by reference.) As used herein, a “substrate” is any object, structure, or material surface that contacts the cutting edge of a bladed tool, object, structure, or other bladed instrument. “Cutting” is cleavage, or the separation of discrete parts along natural lines of division, and there are different modes of cutting, such as: (1) slicing, (2) tearing, and (3) wedging (see Paquette and Levin, page 163, right column, second full paragraph). The cutting edge of a bladed instrument is the cutting surface of the instrument.
Proper clearance is important if the edge is to make contact with enough pressure and precision to take full advantage of rake and fineness. Where there is insufficient clearance, force used in pressing the blade against the substrate is dissipated over the entire area of contact instead of being concentrated at the cutting edge where it belongs. Thus, for example, scaler edges lacking adequate clearance must be pressed against a tooth with proportionately greater force than correctly adjusted instruments to produce a comparable effect.
The clearance angle β, as shown in for example
In FIG. 3A,clearance angle β=90°−γ;
In FIG. 3B,clearance angle β=90°−γ−α;
In FIG. 3C,clearance angle β=90°−(γ−α)=90°−γ+α;
Those ordinarily skilled in the art will appreciate from the description above of the apparatus of that in one embodiment, there is provided a finishing device for dental scaling instruments. The shaping and sharpening device is designed to restore and improve the original, precise sharpness and shape to the tip or blade of a bladed instrument. The sharpening and shaping device comprises a block of abrasive material such as ceramic or aluminum oxide. The block as a support means 40 comprises on its surface at least one groove having a specific, cross-sectional profile of finishing area 43.
The profile of the groove 54 may be widely varied, depending on the article to be finished and the surface zones to be finished while excluding or not touching contiguous zones of the surface that are to remain unfinished. For example, the conventional dental tool known as the curet has two different ends, each having a similarly shaped blade. The abrasive cross-sectional profiles of the apparatus allows for the sharpening and shaping of either end of a dental curet and does so whether the instrument is new or used and worn.
As will be appreciated, as most dental manufactures use “eye-hand precision” to make the lateral surfaces, e.g., 18, 18′, the clearance varies from instrument to instrument, without true reproducible geometry as made possible by embodiments as disclosed herein.
In another embodiment, the apparatus can be configured to finish scissors, where single ended cutting edges and channel-grooves may have one abrasive wall, and a guiding wall.
The portion 49 is a relief; corresponding to the zones to remain unfinished and not projecting towards the inserted curet 10 and therefore incapable of contact with any surface of the curet 10. In this way, during finishing of curet's 10 lateral surface 20, the back 14 of curet 10, which is a surface zone contiguous to lateral surface 20, remain unexposed to modification by finishing, and thus preserving the back from loss of metal through abrasion. The relief portion 49 may have a wide variety of cross-sectional side profiles, ranging from square to oval or elliptical. When the surface to be finished is linear or relatively flat, the relief portion 49 is advantageously below the cutting portions 43, 44. Where the article to be finished has a curvilinear surface, for example a curet 10, the relief portion 49 may be below or above the abrasive portions 43, 44.
Referring back to
The apparatus 50 has a generally flat upper surface and is made of hardened abrasive material to abrade select zones of metal surfaces on curet 10, thus sharpening and shaping it. The curet 10 is held by the dentist, while one of the respective two ends, is inserted and drawn through the appropriate groove 54, in order to sharpen and shape the blade or cutting edge of curet 10.
The curet 10 is generally held to correspond to the tip of the dental curet 10 to the particular shape of the groove 54, as described above in relation to
The block 52 may be generally fabricated from a hardened, abrasive material such as a ceramic, aluminum oxide or metal carbide (such as tungsten carbide). The block 52 may be manufactured by dry powder compaction techniques, or by extruding the material through a die, in which case the finishing area 43, 44 is an exposed surface of the abrasive block 52. In an alternate embodiment, block 52 may be fabricated from a plurality of different abrasive materials, so that the finishing area 43, 44 is a composite of different abrasive materials, each selected for its particular affect on article surfaces to be finished. For example, where a coarse abrasion is required, the corresponding negative image portion of finishing area 43, 44 may have a coarser abrasive than an adjacent zone where the corresponding surface portion of the article is only to be polished.
In some embodiments, the apparatus may be machine operated. For example, the tip or blade edge of a dull and/or worn instrument, such as a curet 10, is sharpened and shaped by an apparatus by inserting the blade or tip of the curet into an appropriate groove 54 as illustrated in
In some embodiments, the apparatus includes a pivot in the base of the channel that facilitates pivoting the instrument to be shaped, such as a curet 10, within the apparatus as the instrument is moved against the abrasive surface. In certain further embodiments, the pivot is within a channel groove that serves as a track to draw the pivot along the channel. In some embodiments, the pivot stabilizes the instrument within the channel to permit the sharpening, shaping, and finishing of the instrument to a desired specification, such as restoration of the original clearance angle or the creation of a new desired clearance angle.
In certain embodiments, the apparatus may be used for finishing a zone on the surface of a skate blade. The design of the skate blade must be able to support a skater's quick acceleration, turns, and stops. This is accomplished by grinding a slight hollow into the bottom of the blade. This creates two sharp edges that “bite” into the ice, and prevent slipping.
The groove 954 also includes a circular surface 960 that has a radius R, which is the radius of hollow grind. The circular surface 960 may be an abrasive surface or non-abrasive surface. The radius R of hollow grind must be centered down the middle of the skate blade. The relief 949 can be rounded, rectangular, square, flat, or other shapes. The relief acts as a non-abrasive guiding wall. In some embodiments, the walls 943 and 944 are non-abrasive and fully adjustable or non-adjustable in order to act as guides for selectively restoring the appropriate ROH centered down the middle of the skate blade by an abrasive circular surface 960. In other embodiments, the circular surface 960 is non-abrasive and acts as a relief surface and/or guide when walls 943 and 944 are abrasive to shape the lateral surfaces 820 and 820′ of the skate blade.
The orthopedic curet sharpening apparatus 1150 is a sharpening and shaping device comprising a block 1105 of hardened abrasive material designed to abrade the lateral surfaces of the orthopedic curet. The orthopedic curet sharpening apparatus 1150 contains one or more channels or grooves 1154 that contact the lateral surface 1112 of the orthopedic curet 1110 when it is inserted into the appropriate groove 1154 and drawn against the abrasive area. The apparatus 1150 can be manufactured with different grooves corresponding to the different orthopedic curet shapes and sizes. Drawing the cutting edge of the curet 1110 through a particular groove will impart with precision a particular shape to the end of the tool.
As shown in
The relief portion 1165 may be designed to serve as a honing guide to control the orthopedic curet 1110 at the back 1114 during movement through the channel, and can allow pivoting around a horizontal or vertical axis, or elliptical movements.
In
The orthopedic curet sharpening apparatus 1250 contains one or more channels or grooves 1254 that contact the lateral surface 1212 of the orthopedic curet 1210 when it is inserted into the appropriate groove 1254 and drawn against the abrasive area. Compared with the orthopedic curet sharpening apparatus 1150 shown in
In some embodiments, the apparatus includes a pivot in the base of the channel that stabilizes the orthopedic curet 1210 and facilitates pivoting the curet within the apparatus as the instrument is moved against the abrasive surface. In certain further embodiments, the pivot is within a channel groove that serves to guide the orthopedic curet along the channel while it is in the pivot. In certain embodiments, the pivot can rotate freely and slide down through the channel at the relief area 1265 on, for example, a rail from areas near location 95 to location 96 in apparatus 1250.
In another embodiment, by using a curet sharpening apparatus 1250 shown in
In certain embodiments, the article of manufacture to be sharpened by an apparatus is a scissors or shears. An apparatus can sharpen, shape, and finish any type of scissors and shears, including hair scissors; fabric scissors; embroidery scissors; bandage scissors; cuticle, nail, and pedicure scissors; standard office and home scissors; kitchen scissors; and gardening shears, such as pruning shears. There are two halves to a pair of scissors: the upper and lower shear blade. The cutting edges on the upper and lower shear blades are the essential, sharply ground working parts of the scissors. The finer the cutting requirements on a pair of scissors (e.g., embroidery scissors), the more pointed and narrower the tip needs to be. In certain instances, when a shear blade becomes worn, such as the shear blades on a pair of hair scissors, the blade needs re-convexing to increase the function of the shear. Accordingly, in certain embodiments, an apparatus is configured to restore the convex edge of a hair shear to its original or desired shape.
In certain embodiments, the article of manufacture to be sharpened by an apparatus is a screw. An apparatus can sharpen, shape, and finish any type of screw, including screws having thread varieties selected from wood, machine, sheet metal, high-low, and self-tapping. Screws made from any kind of material are suitable for sharpening, shaping, and finishing in an apparatus, including screws made from steel, brass, aluminum, or nylon and with or without a finish, such as zinc plating, black oxide, or a non-stick coating. Likewise, an apparatus can be configured to sharpen, shape, and finish a screw of any diameter and length. In certain embodiments, the screw is an orthopedic screw or other screw for use in vivo.
When sharpening the screw, as shown in
As used throughout the specification and claims, the term “abrasive surface” includes surfaces fabricated from sandpaper, emory cloth, diamond surfaces, steel wools, jeweler's rouge, liquid abrasives and all conventional and known abrasives in their various abrasive grades, ranging from coarse to very fine grit or particle size. Thus, the abrasive surfaces may be fabricated from materials which differ from or are identical to the material comprising the support means.
As will be appreciated, finishing process includes shaping, sharpening, surface roughness control for kitchen knives, lawn mower blades, orthopedic curettes, neurosurgical curettes, ice skates, wood planing instruments, gouges, saws, screws, and scissors.
It will be appreciated by those ordinarily skilled in the art that the foregoing brief description and the following detailed description are exemplary (i.e., illustrative) and explanatory of the subject matter as set forth in the present disclosure, but are not intended to be restrictive thereof or limiting of the advantages that can be achieved by the present disclosure in various implementations. Additionally, it is understood that the foregoing summary and ensuing detailed description are representative of some embodiments as set forth in the present disclosure, and are neither representative nor inclusive of all subject matter and embodiments within the scope as set forth in the present disclosure. Thus, the accompanying drawings, referred to herein and constituting a part hereof illustrate embodiments of this disclosure, and, together with the detailed description, serve to explain principles of embodiments as set forth in the present disclosure.
This application is a continuation of U.S. patent application Ser. No. 15/241,252 filed on Aug. 19, 2016, which is a continuation of U.S. and International Application Serial Number PCT/US/2015/041998 filed Jul. 24, 2015, which claims the benefit of priority to Provisional Application Ser. No. 62/029,329, filed Jul. 25, 2014. The foregoing applications are each incorporated by reference in their entirety herein.
Number | Date | Country | |
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62029329 | Jul 2014 | US |
Number | Date | Country | |
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Parent | 15241252 | Aug 2016 | US |
Child | 15898900 | US | |
Parent | PCT/US2015/041998 | Jul 2015 | US |
Child | 15241252 | US |