Patent Application
20220288704
The present invention involves rotatable cutting tools, and more particularly relates to an enhanced shank portion of rotatable cutting tools and/or a friction ring component thereof.
Rotatable cutting tools may be used for the impingement of a substrate or earth strata such as, for example, asphaltic roadway material, coal deposits, mineral formations and the like. Cutting tools can experience extreme wear and failure in a number of ways due to the environment in which they operate requiring that they be frequently replaced.
In polycrystalline diamond (PCD) applications in particular, with the increased weight of the cutting portion (or cutting head) and resulting increased rotation of the tool, the shank (and/or associated components) of the cutting tool are subjected to more wear and loading. This becomes a limiting factor on the life of the cutting tool.
Thus, it would be helpful to be able to provide an improved cutting tool or cutting tool assembly that experiences less wear and mechanical failure and therefore an increase in useful tool life as compared to conventional cutting tools.
It would also be helpful to be able to provide an improved cutting tool or cutting tool assembly suitable for the PCD application and/or other applications where a cutting portion of relatively high mass is utilized.
Cutting tools and cutting tool assemblies are provided that include a “friction ring” (also referred to herein as a “braking ring” or a “rotation-limiting element”). The friction ring may be provided in (disposed/secured within) a retaining groove (e.g., provided in the form of a retaining groove) of a shank of the cutting tool. The friction ring may be formed from a resilient and non-rigid material. The friction ring may be secured in the retaining groove of a shank by a retainer ring. The cutting tools may also include a shank having an increased diameter to provide increased strength and allow for a heavier cutting portion (or cutting head) of the cutting tool. The cutting tools and cutting tool assemblies may also include a washer fitted about the shank and positioned adjacent to a back side (or rearward/proximal facing portion) of the cutting portion of the cutting tool.
The friction ring can be configured such that additional portions of the friction ring reposition to be at an outer periphery of the friction ring as the retainer ring is disposed to increase compression of the friction ring. In example embodiments, a friction ring is provided in the form of axially interconnected (e.g., integrally formed) structures (e.g., toroidal or donut shaped) each of which is circumferentially disposed about the shank (within the retaining groove). In other example embodiments, the friction ring is provided in the form of circumferentially interconnected (e.g., integrally formed) axial structures (e.g., generally X-shaped, D-shaped or radial protrusions, as shown herein) which, when the friction ring is disposed/secured within a retaining groove of a tool shank, are sequentially axially disposed about the shank within the retaining groove.
An aspect of the invention is to provide a cutting tool comprising: a cutting tool body that is generally symmetrically formed about a central longitudinal axis of the cutting tool, the cutting tool body including a cutting head at a distal end portion of the cutting tool, the cutting head including a cutting member, and a shank axially rearward of and connected to the cutting head, the shank including a retaining groove provided therein; and a friction ring disposed within the retaining groove.
Another aspect of the invention is to provide a cutting tool assembly comprising: a cutting tool holder having a central longitudinal axis; and a cutting tool at least partially disposed within a substantially cylindrical chamber of the cutting tool holder, the cutting tool including a cutting tool body including a cutting head at a distal end portion of the cutting tool, the cutting head including a cutting member, and a shank axially rearward of and connected to the cutting head, the shank including a retaining groove provided therein at a proximal portion of the shank, a friction ring positioned within the retaining groove, and a retainer ring secured about the friction ring.
A further aspect of the invention is to provide a braking apparatus for a cutting tool assembly with a rotatable cutting tool and a cutting tool holder, the braking apparatus comprising: a resilient rotation limiting structure configured to be fitted within a retaining groove of the rotatable cutting tool and compressibly secured therein by a retaining structure disposed at an outer periphery of the resilient rotation limiting structure such that the resilient rotation limiting structure is outwardly radially self-biased causing the retaining structure to bear against an inside wall of the cutting tool holder imparting frictional resistance to rotational movement of the rotatable cutting tool within the holder.
Referring now to
Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about”, “approximately”, and “substantially”, is not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Herein and throughout the specification and claims, range limitations may be combined and/or interchanged, such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise.
With reference to
Referring now to
With reference to
The convex shape section 40 of the bolster portion 36 can have a radius, for example, in the range of about 30 mm to about 35 mm. Advantageously, this configuration of having the radius, R, provides the necessary structure and support for the cutting member 34. In addition, this configuration advantageously provides, for example, the ability to add mass or size to the bolster portion 36 for improved wear while still maintaining a streamlined design for efficient cutting. In example embodiments, the bolster portion 36 is formed, at least in part, of a cemented (cobalt) tungsten carbide material that allows for the bolster portion 36 to retain its shape and integrity for a longer period of time during use.
The cutting member 34 can include a super hard material 50, e.g., provided in the form of an outer layer of the cutting member 34. The super hard material 50 can be made of, for example, polycrystalline diamond (PCD) or polycrystalline cubic boron nitride (PcBN).
With reference to
In regard to reducing/stopping the rotation of the cutting tool 14 (e.g., in relation to the holder 12), in example embodiments, the cutting tool 14 includes a friction ring 79, positioned (and secured) within a retaining groove 32 of the shank 30, and a retainer ring 80 (e.g., a wedding band style retainer ring) secured about the friction ring 79 (and, in example embodiments/implementations, partially within the retaining groove 32). The retainer ring 80 is shaped and configured to secure the friction ring 79 in the retaining groove 32, which by way of example can be provided in the form of an annular groove 92 such as described and/or depicted herein, or in other forms suitable for receiving a friction ring therein.
In this example embodiment, the retaining groove 32 is provided at a proximal portion 33 of the shank 30 (e.g., as shown). By way of example, the retaining groove 32 has a width (measured axially along the central longitudinal axis A-A) of around 13 mm and a depth of around 4.1 mm, in relation to the (cylindrical surface of the) shank 30, which has a diameter of around 20 mm. The aforementioned shank diameter of around 20 mm is approximately 3 mm larger than in conventional cutting tools and serves, in example embodiments, to accommodate tools having heavier cutting heads by increasing the diameter (and therefore also the mass) of the shank 30 which increases shank strength and durability and, for designs including a cutting head of increased mass, provides a counterbalance (in mass) that serves to migrate proximally (along the central longitudinal axis A-A) a center of mass of the cutting tool body 22.
In example embodiments, the shank 30, the friction ring 79, the retainer ring 80 and the cutting tool holder 12 are (respectively sized and/or shaped and) configured such that the cutting tool body 22 is (supported by and) rotatable within the cutting tool holder 12 (i.e., about the central longitudinal axis (A-A)) with the retainer ring 80 bearing against an inside wall 81 of the cutting tool holder 12 (imparting frictional resistance to rotational movement of the cutting tool body in relation to the holder slowing the rotational speed of the tool—e.g., slowing tool rotation speed by 25-50% which could increase the useful tool life by potentially 25-50%). The resistance to rotation (or frictional resistance) can be, for example, from 1 in-lb to fixed, greater than 1 in-lb, greater than 0.5 ft-lb, greater than 1 ft-lb, from 1 to 100 ft-lb or from 1 to 150 ft-lb of torque on the tools. Install and remove force of the tools can be between 100 and 1000 lbs. The thickness of the friction ring 79 (e.g., formed from urethane) can be, for example, between 0.080 inches and 0.5 inches; and the diameter of the retainer ring 80 (e.g., metal retainers) can be, for example, between 0.5 inches and 1.75 inches.
In example embodiments, the shank 30, the friction ring 79, the retainer ring 80 and the cutting tool holder 12 are (respectively sized and/or shaped and) configured such that the retainer ring 80 is fixed or secured in position in relation to the inside wall 81 of the cutting tool holder 12 and compressed sufficiently tightly about the friction ring 79 to prevent the cutting tool body 22 from rotating within the holder 12 (e.g., providing an indexable cutting tool).
In example embodiments, the shank 30, the friction ring 79, the retainer ring 80 and the cutting tool holder 12 are (respectively sized and/or shaped and) configured such that an outer periphery (i.e., radially outward periphery) 160 (
The term “friction ring” as used herein can be construed to mean a component, apparatus or device, whether a single element or an assembly: configured to selectively interface and frictionally engage with a cutting tool body and a cutting tool holder to reduce or stop rotation of the cutting tool (e.g., in relation to the holder); which is resilient, generally ring-shaped, configured to be fitted within a retaining groove (e.g., an annular groove) of a shank portion of the cutting tool body and radially inwardly compressed and secured within the retaining groove and that may be positioned radially inside/concentrically within an outer retainer ring; which includes surfaces that may make frictional contact with adjacent elements (i.e., a radial inner surface of the friction ring that may frictionally engage an outer radial surface of the retaining/annular groove and/or side edges of the friction ring that may frictionally engage sidewalls of the retaining/annular groove; and a radial outer surface of the friction ring that produces frictional contact with the radial inner surface of the cylindrical inside wall of the holder (either through direct contact therebetween or by pressing against a retainer ring located radially outside and at least partially surrounding the friction ring); which may have continuous and/or discontinuous friction contact surfaces/features, e.g., projections and recesses spaced circumferentially around the inner and/or outer surfaces of the friction ring and/or spaced along the longitudinal axis of the friction ring; and for embodiments including a retainer ring, the friction ring having outer radial surface(s) that may frictionally engage an inner radial surface of the retainer ring, and being configured in conjunction with the retainer ring and/or the holder such that an outer radial surface of the retainer ring may, in turn, frictionally engage the radial inner surface of the cylindrical inside wall of the holder. The friction ring 79 can be a unitary (solid) element or structure (e.g., provided in the form generally of a C-shaped split ring) and, in example embodiments, is made of a resilient (and/or structurally reconfigurable) material or materials 150 including, for example, nylon, neoprene, polyurethane, rubber, epoxy resin, foam, or a combination thereof.
Friction rings can be provided in other forms as well. By way of example and referring to
In other example embodiments, friction rings are provided in the form of circumferentially interconnected (e.g., integrally formed) axial structures which are sequentially axially disposed about the shank 30 within the retaining groove 32. Referring to
Referring to
Referring to
Thus, in an example embodiment, a cutting tool includes: a cutting tool body that is generally symmetrically formed about a central longitudinal axis of the cutting tool (e.g., at all or substantially all, or some, locations therealong), the cutting tool body including a cutting head at a distal end portion of the cutting tool, the cutting head including a cutting member (at an axial forward end of the cutting head), and a shank axially rearward of and connected to the cutting head, the shank including a retaining groove provided therein (at a generally proximal portion of the shank); and a friction ring disposed (/positioned/seated/secured) within the retaining groove. In example embodiments, the cutting tool further includes a retainer ring (e.g., a wedding band style retainer ring) secured about the friction ring (and partially within the retaining groove). In example embodiments, the shank exclusive of the retaining groove has a diameter that is less than an outer diameter of the retainer ring when the retainer ring is secured (/compressed/installed) about the friction ring. In example embodiments, the shank exclusive of the retaining groove has a diameter that is greater than an outer diameter of the friction ring when the friction ring is compressed by the retainer ring installed thereabout. The cutting member comprises, for example, polycrystalline diamond (PCD) or polycrystalline cubic boron nitride (PcBN). In example embodiments, the retaining groove has a diameter that is from 50 to 75% of a diameter of the shank exclusive of (and adjacent to) the retaining groove. The friction ring can comprise (or consist of) nylon, neoprene, polyurethane, rubber, epoxy resin, foam, or a combination thereof. In example embodiments, the friction ring (e.g., 60 D abrasion resistant urethane) has a coefficient of friction greater than that of the retainer ring (e.g., made of spring steel). In example embodiments, the friction ring has an outer diameter, when the friction ring is compressed by the retainer ring installed thereabout, that is from 15 to 20 mm. In example embodiments, the friction ring has a (radial) thickness ranging from 30 percent to 120 percent of a depth of the retaining groove.
Thus, in an example embodiment, a cutting tool assembly includes: a cutting tool holder having a central, longitudinal axis (A-A); and a cutting tool at least partially disposed (and secured) within a substantially cylindrical chamber (e.g., a bored recess) of the cutting tool holder, the cutting tool including a cutting tool body—including a cutting head at a distal end portion of the cutting tool, the cutting head including a cutting member (at an axial forward end of the cutting head), and a shank axially rearward of and connected to the cutting head, the shank including a retaining groove provided therein (e.g., at a proximal portion of the shank)—a friction ring positioned (and secured) within the retaining groove, and a retainer ring (e.g., a wedding band style retainer ring) secured about the friction ring (and, in example embodiments/implementations, partially within the retaining groove). In example embodiments, the cutting tool assembly further includes: a washer fitted about the shank and positioned against or adjacent to a base portion of the tool, the washer and the cutting tool holder being configured (e.g., with complementary surfaces) for establishing and maintaining alignment of the cutting tool body with the cutting tool holder (when the body is disposed/positioned/secured within the holder). The retainer ring is shaped and configured to secure the friction ring in the retaining groove. In example embodiments, the retainer ring is partially disposed within the retaining groove. In example embodiments, the cutting tool assembly is configured such that a frictional resistance provided by the friction ring in combination with the retainer ring is greater than that (the frictional resistance) provided by the retainer ring alone (positioned/secured about the shank). In example embodiments, the shank, the friction ring, the retainer ring and the cutting tool holder are (respectively sized and/or shaped and) configured such that the cutting tool body is (supported by and) rotatable within the cutting tool holder (i.e., about the central, longitudinal axis (A-A)) with the retainer ring bearing against an inside wall of the cutting tool holder (imparting frictional resistance to rotational movement of the cutting tool body in relation to the holder slowing the rotational speed of the tool—e.g., slowing tool rotation speed by 25-50% which could increase the useful tool life by potentially 25-50%). In example embodiments, the shank, the friction ring, the retainer ring and the cutting tool holder are (respectively sized and/or shaped and) configured such that the retainer ring is fixed or secured in position in relation to an inside wall of the cutting tool holder and compressed sufficiently tightly about the friction ring to prevent the cutting tool body from rotating within the holder (e.g., providing an indexable cutting tool). In example embodiments, the shank, the friction ring, the retainer ring and the cutting tool holder are (respectively sized and/or shaped and) configured such that an outer periphery (i.e., radially outward periphery) of the friction ring is compressed radially inwardly when the shank is in the holder—this radially inward compression being substantially uniform in magnitude (at different locations) along the radially outward periphery. In example embodiments, the shank, the friction ring, the retainer ring and the cutting tool holder are (respectively sized and/or shaped and) configured such that the friction ring provides sufficient frictional resistance against rotation of the cutting tool in relation to the cutting tool holder that, in its effect on the cutting tool, ranges from preventing free-spinning to fixed (i.e., preventing rotation). In example embodiments, the cutting tool, the friction ring, the retainer ring and the cutting tool holder are configured such that the friction ring provides frictional resistance resulting in greater than 0.1 ft-lb torque applied to the cutting tool being required to rotate the cutting tool within and in relation to the cutting tool holder. In example embodiments, the friction ring is made of a resilient (and/or structurally reconfigurable) material or materials and is provided in the form of axially interconnected (e.g., integrally formed) structures (e.g., toroidal or donut shaped) each of which is circumferentially disposed about the shank (within the retaining groove). In example embodiments, the friction ring (e.g., provided in the form generally of a C-shaped split ring) is made of a resilient (and/or structurally reconfigurable) material or materials and is provided in the form of circumferentially interconnected (e.g., integrally formed) axial structures which are sequentially axially disposed about the shank. By way of example, the circumferentially interconnected axial structures can be generally X-shaped inclusive of radially outwardly biased spring portions, generally D-shaped inclusive of radially outwardly biased spring portions and axially extending channels (or hollow portions) defined by each of the structures respectively, or radial protrusions (and/or other structures) that are biased to maintain/return to a radially outwardly directed (and/or uncompressed) shape.
The friction rings described herein embody (different examples of) a braking apparatus 130 for a cutting tool assembly with a rotatable cutting tool and a cutting tool holder.
Thus, in an example embodiment, a braking apparatus (for a cutting tool assembly with a rotatable cutting tool and a cutting tool holder) includes: a resilient rotation limiting structure configured to be fitted (about and) within a retaining groove (e.g., an annular groove) of the rotatable cutting tool and compressibly secured therein by a retaining structure disposed at an outer periphery of the resilient rotation limiting structure such that the resilient rotation limiting structure is outwardly radially self-biased causing the retaining structure to bear against an inside wall (or other interior portion) of the cutting tool holder imparting frictional resistance to rotational movement of the rotatable cutting tool within and in relation to the holder (e.g., slowing the rotational speed of the tool). The resilient rotation limiting structure is configured such that, for example, additional portions of the structure reposition to the outer periphery (of the resilient rotation limiting structure) as the retaining structure is disposed to increase compression of the resilient rotation limiting structure—or the outer periphery inwardly repositions responsive to increased compression such that additional (repositioning) portions of the structure become part of the outer periphery. The resilient rotation limiting structure includes, for example, a generally ring-shaped structure provided in the form of axially interconnected (e.g., integrally formed) toroidal or donut shaped structures which are sequentially circumferentially disposed (e.g., parallel in their respective planes) from side to side laterally across the generally ring-shaped structure. In example embodiments, the resilient rotation limiting structure includes a generally ring-shaped structure provided in the form of circumferentially interconnected (e.g., integrally formed) axial structures which are sequentially axially disposed moving circumferentially along an outer periphery of the generally ring-shaped structure. By way of example, the circumferentially interconnected axial structures can be generally X-shaped inclusive of radially outwardly biased spring portions, generally D-shaped inclusive of radially outwardly biased spring portions and axially extending channels (or hollow portions) defined by each of the structures respectively, or radial protrusions that are (radially outwardly biased and) sequentially equidistantly positioned along an outer periphery of the generally ring-shaped structure.
While example embodiments have been described herein, it should be apparent, however, that various modifications, alterations and adaptations to those embodiments may occur to persons skilled in the art with the attainment of some or all of the advantages of the subject matter described herein. The disclosed embodiments are therefore intended to include all such modifications, alterations and adaptations without departing from the scope and spirit of the technologies and methodologies as described herein.
