Oscillating surgical cutting tool

[0001] In accordance with 37 C.F.R. 1.76, a claim of priority is included in an Application Data Sheet filed concurrently herewith. Accordingly, the present invention claims priority as a Continuation of U.S. patent application Ser. No. 16/773,564 filed on Jan. 27, 2020, which is a Continuation of U.S. patent application Ser. No. 15/928,885, entitled “OSCILLATING SURGICAL CUTTING TOOL”, filed Mar. 22, 2018. The contents of the above referenced application are incorporated herein by reference in its entirety.

[0002] The present invention generally relates to cutting tools; and more particularly, to a cutting tool having straight flutes and being constructed to cut when oscillated in a rotary motion in either direction around a longitudinal axis.

[0003] The prior art has provided cutting tools that remove material when rotated. These tools typically include one or more helix cut into the tool; the helix all arranged in the same direction and parallel if more than one helix is present. The helix may be cut for left hand rotation or for right hand rotation of the tool. The leading edge of each helix is provided with a sharpened edge that cuts the material when rotated, while the helix moves the cut material away from the cutting action. The rear edge of the helix is provided with relief so as not to drag on the edge of the cut surface.

[0004] U.S. Pat. No. 9,232,953 issued to Bono, the inventor of the present cutting tool, provides a cutting tool for bone, cartilage and disc material that includes at least one helix arranged in a first direction and at least one helix arranged in a second direction so that the cutting tool can be oscillated back and forth to cut. However, it has been found that this construction may not remove material fast enough during oscillation for some surgical procedures.

[0005] Therefore, it would be desirable to provide a rotary cutter configuration that cuts both directions when oscillated back and forth to quickly cut bone, cartilage and disc, while minimizing any form of change to soft tissues during removal of the bone, cartilage and disc tissue.

[0006] Thus, the present invention provides a surgical rotary cutting tool which overcomes the disadvantages of prior art surgical cutting tools by providing a rotary surgical cutting tool having straight flutes with each side of the flute being provided with a cutting edge to provide cutting in both directions during limited oscillatory motion.

[0007] Briefly, the present invention provides a cutting tool for surgical procedures. More specifically, the present invention provides a rotary surgical cutting tool which overcomes the disadvantages of prior art surgical cutting tools by providing a rotary cutting tool having straight flutes with each side of the flute being provided with a cutting edge that permits cutting in both directions during limited oscillatory motion of the rotary surgical cutting tool. The areas between the cutting edges are provided with relief to reduce friction while the flute moves the cut material away from the cutting edges.

[0008] Accordingly, it is an objective of the present invention to provide a rotary surgical cutting tool that functions to cut bone, cartilage and disc materials.

[0009] It is a further objective of the present invention to provide a rotary surgical cutting tool that cuts bone, cartilage and disc materials when oscillated back and forth about a central axis, cutting when moved in both directions.

[0010] It is yet a further objective of the present invention to provide a rotary surgical cutting tool that cuts bone, cartilage and disc materials, and cutting in both directions when oscillated through limited oscillatory motion.

[0011] It is another objective of the present invention to provide a rotary surgical cutting tool having straight flutes, wherein each flute is provided with two opposing cutting surfaces.

[0012] Other objectives and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification, include exemplary embodiments of the present invention, and illustrate various objects and features thereof.

[0031] While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described a presently preferred embodiment with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiments illustrated.

[0032] Referring generally to FIGS. 1-18, a surgical cutting tool 100 for cutting bone and tissue is illustrated. The surgical cutting tool includes a shank 2 having a longitudinal axis 4, a first end 8, and a second end 10. The shank 2 has a perimeter surface 6 (FIG. 13) extending around the longitudinal axis 4 and being symmetrically shaped to allow at least the second end 10 of the perimeter surface 6 to be gripped for rotation about the longitudinal axis 4. Thus, the longitudinal axis 4 is also a rotational axis. In a preferred embodiment, the second end of the shank 10 is round to cooperate with collets, sleeves, drill chucks and the like, as is known in the art. In at least one embodiment, the second end of the shank 10 includes one or more flats 12. The flats 12 are constructed and arranged to cooperate with set screws, tangent pins or the like (not shown) to assure that the surgical cutting tool 100 oscillates the same speed and arc of rotation as the reciprocating grinder 50 (FIG. 18) driving the surgical cutting tool 100. The first end 8 of the shank 2 includes a cutter 14, the cutter including an outside diameter 16; the cutter 14 including two or more flutes 18, each flute 18 extending parallel to the longitudinal axis 4 and extending inward from the outside diameter 16 toward the longitudinal axis 4, forming a recessed flute channel 20; each flute channel 20 having a pair of opposing sidewalls 22, 24 and a cylindrical radius at the base of each flute. Each sidewall forms a face 26 of a cutting edge 42 extending along the length of each flute channel 20 so that each flute channel 20 provides two opposing faces 26 providing cutting edges 42, allowing the cutter to cut in both directions when rotationally oscillated around the longitudinal axis 4. To enhance the cutting action and reduce pressure on the cutter 14, each face 26 includes a rake angle 28, said rake angle being divergent with respect to a center plane 30 extending through said longitudinal/rotational axis 4 when the blade 32 is centered with respect to the center plane 30, and wherein the rake angle 28 is convergent with respect to said center plane 30 when said flute 18 is centered with respect to said center plane 30. Each said blade 32 includes a top rake 34, said top rake 34 extending inwardly from said outside diameter 16 towards said axis of rotation 4 so that the convergence of the face 26 and the top rake 34 provides the outermost diameter of said cutter 14. In at least some embodiments, the top rake 34 is formed by a radius positioned to provide relief behind the face 26 as the cutter 14 is oscillated. In at least some embodiments, the face 26 and top rake 34 may include notches 36 or waves suitable to break the face 26 into shorter segments, thereby reducing load on the face 26 of the cutter 14. These notches 36 may be aligned or, more preferably, offset with respect to each other to eliminate ribs on the cut surface. The cutter 14 may be formed with an even or an odd number of flutes without departing from the scope of the invention. In general, a cutter 14 with a higher number of flutes will remove material faster than a cutter with fewer flutes. The cutter 14 may be formed of the same material and formed integral with the shank 2. Alternatively, the shank 2 and the cutter 14 may be constructed from different materials, and the cutter 14 may be cemented to the shank 2 with silver solder or the like suitable to secure the cutter 14 to the shank 2. In this manner, materials such as high speed steel and/or carbide may be utilized as desired without departing from the scope of the invention. Coatings known in the art such as, but not limited to, titanium nitride, titanium carbonitride, vanadium carbide and the like, having a higher hardness than the base material may be utilized. The flutes 18 may extend around the end of the cutter as illustrated in FIGS. 1-9, or alternatively, the end of the cutter may not be constructed to cut as illustrated in FIGS. 10-12.

[0033] Referring to FIGS. 13-17, an alternative embodiment of the present device is illustrated. In this embodiment, the shank 2 is constructed to include shank flutes 40. The shank flutes 40 extend along the length of the shank 2 and extend inwardly from the outer diameter 16 to reduce the rotating weight of the surgical cutting tool 100. In this manner, the surgical cutting tool 100 can be oscillated at faster speeds, reducing the inertia of the surgical cutting tool as its direction is changed. The shank flutes 40 may be constructed as flats, channels or any other shape suitable for reducing the rotating mass of the shank without departing from the scope of the invention.

[0034] Referring to FIG. 18, the surgical cutting tool 100 is illustrated within an oscillating grinder. Such a grinder is described in U.S. Pat. No. 9,232,953, granted to the owners of the present application.

[0035] It is to be understood that while a certain form of the invention is illustrated, it is not to be limited to the specific form or arrangement of parts herein described and shown. It will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention, and the invention is not to be considered limited to what is shown and described in the specification.

[0036] One skilled in the art will readily appreciate that the present invention is well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as those inherent therein. Any compounds, methods, procedures and techniques described herein are presently representative of the preferred embodiments, are intended to be exemplary, and are not intended as limitations on the scope. Changes therein and other uses will occur to those skilled in the art which are encompassed within the spirit of the invention and are defined by the scope of the appended claims. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are obvious to those skilled in the art are intended to be within the scope of the following claims.