Patent Description:
One issue common to most cutting blade assemblies, and especially those incorporated in a grinder pump or other fluid pumping applications, is the efficient processing and jam-free operation of the cutting blade assembly given the wide variety of debris encountered. For instance, with grinder pumps, debris including rags, mop heads, beverage containers, diapers, coins, and other objects can clog and jam the cutting blade assembly or place an increased load on the motor driving the cutting blade assembly. The various types of debris present many challenges because stringy debris (e.g., a mop head) can tend to wrap around the cutting blade assembly, resilient debris (e.g., plastic and rubber objects) can tend to wedge between moving parts of the cutting blade assembly, and hard debris (e.g., metallic objects) can wear or damage the cutting features of the cutting blade assembly. One particularly pervasive global problem faced in cutting systems involves the processing of wastewater containing wipes, which can include fibrous materials such as plastic fibers. Fibers can accumulate in gaps and at various interfaces causing a reduction in effectiveness of the cutting system and blockages of the pump.

To address these various problems associated with processing a variety of suspended debris, the drive motor torque can be increased, the cutting blade assembly strengthened, and the allowable particle size increased. However, none of these approaches presents an efficient, cohesive technique to address the persistent issues faced by cutting blade assemblies, and especially those cutting blade assemblies used in grinder pump applications. <CIT> discloses a grinder pump basin system which includes a basin; a cover plate; a bracket secured to the cover plate; and a grinder pump with cutter plate with openings and a cutter blade secured to the bracket above a bottom surface of the basin. The openings in the cutter plate have a unique shape which assists in the cutting of material which flows through an inlet of a grinder pump. The shape of the cutter blade cooperates with the openings in the cutter plate such that solids are forced between these respective components. <CIT> discloses a cutting blade assembly which establishes a bidirectional and/or multifaceted scissor-type cutting action to process various types of debris encountered by the cutting blade assembly. The assembly includes a cutting plate and a cutting hub configured for relative rotation. A cutting slot is formed in the cutting plate and intersects the axial face to define a cutting edge at the intersection of the cutting slot and the axial face. The cutting hub has a cutting arm positioned adjacent to the axial face. When the cutting plate and the cutting hub undergo relative rotation, the cutting arm passes adjacent to the cutting edge to perform a scissor-type cutting action. <CIT>discloses a cutter assembly configured for a grinder pump and comprising a cutter wheel and a cutter disc that interacts with each other. The cutter wheel comprises a shaft portion that is configured to interact with a central hole of said cutter disc, a hub portion that is connected to the shaft portion and at least two main cutting edges that in the radial direction extend outwards from said hub portion and that are configured to interact with a set of cutting holes of said cutter disc, wherein the shaft portion comprises an axially extending cutting recess, and wherein the hub portion comprises a radially extending cutting recess.

In light of at least the above, a need exists for a cutting blade assembly capable of efficiently and effectively processing various types of debris encountered by the cutting blade assembly.

Embodiments of the invention provide a cutting blade assembly comprising the features of claim <NUM>. The cutting blade assembly is operably coupleable to a fluid pump. The cutting blade assembly comprises a cutting plate, a cutting hub, and a plurality of deflection features. The cutting plate has a front axial surface, an opening, and a plurality of cutting holes. Each of the plurality of cutting holes defines at least one cutting edge. The cutting hub is disposed at least partially within the opening of the cutting plate and has a cutting arm and a fin. The cutting arm is adjacent to the front axial surface and defines an arcuate front surface having a leading edge. The fin is adjacent to the front axial surface and proximate to the cutting arm. Each of the deflection features includes an inner end proximate the opening and an outer end at a radial edge of the cutting plate. Additionally, each of the deflection features gradually widens from the inner end to the outer end. The plurality of deflection features are configured to deflect debris radially outward away from the opening when the cutting hub is rotated relative to the cutting plate. When the cutting plate and the cutting hub are rotated relative to each other, the leading edge of the cutting arm passes adjacent to the plurality of cutting holes so that the relative rotation of the cutting plate and the cutting hub defines a cutting action between the leading edge and the at least one cutting edge, and the fin is configured to urge debris away from the opening of the cutting plate.

The at least one cutting edge may be a pair of cutting edges. The pair of cutting edges may be radially separated from each other, thereby allowing for multiple cuttings actions to be defined each time the leading edge of the cutting arm passes over an individual cutting feature of the plurality of cutting features. Each cutting feature of the plurality of cutting features may comprise a C-shaped through hole extending through the cutting plate from the front axial surface to a rear axial surface of the cutting plate. Each cutting feature of the plurality of cutting features may be approximately equidistant from the opening and a radial edge of the cutting plate. Each one of the pair of cutting edges may be disposed on opposite ends of the corresponding cutting feature.

Each of the deflection features may be gradually recessed into the front axial surface from an arcuate leading edge that is flush with the front axial surface to an arcuate trailing edge that is recessed into the front axial surface, thereby forming an angled lower surface. The arcuate leading edge may define a leading radius of curvature and the arcuate trailing edge defines a trailing radius of curvature that is different from the leading radius of curvature.

The following discussion is presented to enable a person skilled in the art to make and use embodiments of the invention. Various modifications to the illustrated embodiments will be readily apparent to those skilled in the art, and the generic principles herein can be applied to other embodiments and applications without departing from embodiments of the invention. Thus, embodiments of the invention are not intended to be limited to embodiments shown, but are to be accorded the widest scope consistent with the principles and features disclosed herein. The following detailed description is to be read with reference to the figures, in which like elements in different figures have like reference numerals. The figures, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of embodiments of the invention. Skilled artisans will recognize the examples provided herein have many useful alternatives and fall within the scope of embodiments of the invention, which is solely limited by the attached claims.

One embodiment of a cutting blade assembly <NUM> is described in the context of a grinder pump. However, the embodiments described herein can be incorporated into other suitable types of cutting devices, such as blenders, mixers, and food processors.

<FIG> illustrate a cutting blade assembly <NUM> configured for use with a grinder pump (not shown). The grinder pump may include the cutting blade assembly <NUM> and a fluid pump. The grinder pump may generally draw fluid and debris into and through an inlet in a pump housing of the grinder pump. The fluid and debris may be processed by the cutting blade assembly <NUM> and the resulting slurry may be directed through the grinder pump, through an internal manifold, toward an outlet of the pump housing. Specifically, the fluid pump may include an electric motor configured to rotate a central drive shaft about a drive axis <NUM> (shown in <FIG>). The drive shaft may be rotatably fixed to an impeller, which may be seated within the pump housing proximate the inlet. As the impeller rotates, fluid and debris may be drawn toward the inlet and engaged by the cutting blade assembly <NUM>.

The cutting blade assembly <NUM> of one embodiment of the invention includes a cutting plate <NUM> and a cutting hub <NUM>. In some instances, the cutting plate <NUM> may be disk-shaped and seated into a mating cylindrical recess formed into an external surface of the pump housing and surrounding the inlet. The cutting plate <NUM> may be rotatably fixed to the mating cylindrical recess by a series of mating features that engage a corresponding plurality of rotational locking notches <NUM> of the cutting plate <NUM>. Each locking notch <NUM> may be recessed into a front axial surface <NUM> of the cutting plate <NUM> at a radial edge <NUM> of the cutting plate <NUM>. In some instances, the plurality of locking notches <NUM> may be disposed evenly-spaced around the circumference of the cutting plate <NUM>.

The cutting hub <NUM> is partially received within a central opening <NUM> (shown in <FIG>, <FIG>) of the cutting plate <NUM> and may be rotatably coupled to the drive shaft of the motor, so that the cutting hub <NUM> rotates in unison with the impeller of the fluid pump. Specifically, the cutting hub <NUM> includes a central opening <NUM> having a keyway <NUM> that may be configured to receive the drive shaft of the motor, and to engage the drive shaft of the motor in a keyway-type rotationally-engaged connection.

It will be appreciated that the cutting hub <NUM> may alternatively or additionally be configured to rotatably engage the drive shaft of the motor in various other manners without departing from the scope of the invention. For example, in some instances, the central opening <NUM> of the cutting hub <NUM> may alternatively include a threaded radially-inward facing surface configured to engage a corresponding threaded portion of the drive shaft.

<FIG> illustrate the structure of and interaction between the cutting plate <NUM> and the cutting hub <NUM> of the cutting blade assembly <NUM>. The cutting plate <NUM> and the cutting hub <NUM> are configured to establish an axial cutting action (i.e., generally parallel to the drive axis <NUM>). This axial cutting action is achieved via relative rotation between the cutting plate <NUM> and the cutting hub <NUM>.

As shown in <FIG>, the cutting plate <NUM> includes the locking notches <NUM>, the central opening <NUM>, a plurality of deflection features <NUM>, and a plurality of cutting features <NUM>. The central opening <NUM> extends through the cutting plate <NUM> from the front axial surface <NUM> to a rear axial surface <NUM> (shown in <FIG>) and defines an inwardly-facing radial wall <NUM>.

In the illustrated non-limiting example, there may be four deflection features <NUM> that are evenly spaced around the circumference of the cutting plate <NUM>. In other embodiments, the shape, number, and relative orientation of the deflection features <NUM> may be altered to accommodate application-specific requirements.

Each of the deflection features <NUM> may be gradually recessed into the front axial surface <NUM> from an arcuate leading edge <NUM> that is flush with the front axial surface <NUM> to an arcuate trailing edge <NUM> that is recessed into the front axial surface <NUM>, thereby forming an angled lower surface <NUM>. Each of the deflection features <NUM> further includes an inner end <NUM> proximate the central opening <NUM> and an outer end <NUM> at the radial edge <NUM> of the cutting plate <NUM>.

Both the arcuate leading edge <NUM> and the arcuate trailing edge <NUM> may extend generally radially outward from the inner end <NUM> toward the outer end <NUM> and may curve from the inner end <NUM> to the outer end <NUM> in a direction of rotation <NUM> of the cutting hub <NUM> (i.e., the direction that the cutting hub <NUM> rotates relative to the cutting plate <NUM> during use). The arcuate trailing edge <NUM> may also have a smaller radius of curvature than that of the arcuate leading edge <NUM>, such that the deflection features <NUM> gradually widen from the inner end <NUM> to the outer end <NUM>. The increasing depth and flow area of the deflection features <NUM> is configured to help gradually deflect debris radially outward away from the central opening <NUM>, when the cutting hub <NUM> is rotated relative to the cutting plate <NUM>.

In the illustrated non-limiting example, there may be twelve cutting features <NUM> that may be grouped into four groups of three, each group may be evenly spaced around the circumference of the cutting plate <NUM> and may be separated by one of the four deflection features <NUM>. In other embodiments, the shape, number, grouping, and relative orientation of the cutting features <NUM> may be altered to accommodate application-specific requirements.

Each of the cutting features <NUM> may form a generally arcuate or C-shaped through hole extending through the cutting plate <NUM> from the front axial surface <NUM> to the rear axial surface <NUM> and may be approximately equidistant from the central opening <NUM> and the radial edge <NUM> of the cutting plate <NUM>. Each cutting feature <NUM> may include an inner end <NUM>, an outer end <NUM>, a leading sidewall <NUM>, and a trailing sidewall <NUM>. The inner end <NUM> may be disposed proximate the central opening <NUM>. The outer end <NUM> may be disposed proximate the radial edge <NUM> of the cutting plate <NUM>. Both the inner end <NUM> and the outer end <NUM> may be angled or skewed in the direction of rotation <NUM> of the cutting hub <NUM>. As such, each of the leading sidewall <NUM> and the trailing sidewall <NUM>, and therefore the cutting feature <NUM> as a whole, may form a generally C-shaped element with the concave side of the "C" shape pointing in the direction of rotation <NUM> of the cutting hub <NUM>.

The leading sidewall <NUM> may be disposed on the convex side of the cutting feature <NUM>. As best illustrated in <FIG>, the leading sidewall <NUM> may extend between and generally perpendicularly to the front and rear axial surfaces <NUM>, <NUM>. The trailing sidewall <NUM> may be disposed on the concave side of the cutting feature <NUM>. As best illustrated in <FIG>, the trailing sidewall <NUM> may extend between the front and rear axial surfaces <NUM>, <NUM>, at an angle relative to each of the front and rear axial surfaces <NUM>, <NUM>. Specifically, the trailing sidewall <NUM> may extend from the front axial surface <NUM> toward the rear axial surface <NUM> at an angle with respect to the drive axis <NUM> such that the trailing sidewall <NUM> is angled in the direction of rotation <NUM> of the cutting hub <NUM> from the front axial surface <NUM> to the rear axial surface <NUM>. As such, the cutting feature <NUM> may gradually widen from the front axial surface <NUM> to the rear axial surface <NUM>, and a pair of cutting edges <NUM> is formed between the trailing sidewall <NUM> and the front axial surface <NUM>. Specifically, the trailing sidewall <NUM> may define a pair of negative semi-frustoconical shaped surfaces <NUM> (i.e., each of the surfaces <NUM> form the outside of a semi-frustoconical shaped cavity) connected by a central semi-frustoconical shaped surface <NUM> that is oppositely-oriented (i.e., upside-down with respect to the semi-frustoconical shape of the surfaces <NUM>). The pair of cutting edges <NUM> may be disposed at the narrow ends of the negative semi-frustoconical shaped surfaces <NUM>, thereby providing two distinct cutting edges <NUM>, separated by the central surface <NUM>, for each cutting feature <NUM>.

Referring now to <FIG>, one of the pair of cutting edges <NUM> may be disposed proximate the inner end <NUM> of the cutting feature <NUM> and the other cutting edge <NUM> may be disposed proximate the outer end <NUM> of the cutting feature <NUM>. Thus, the pair of cutting edges <NUM> may be radially separated from each other. Therefore, the pair of cutting edges <NUM> allows for debris to be cut multiple times each time a single cutting arm <NUM> of the cutting hub <NUM> passes over a single cutting feature <NUM>. As shown in <FIG>, the leading-most edge of the radially inner cutting edge <NUM> may be tangential to ray R1 and the leading-most edge of the radially outer cutting edge <NUM> may be tangential to ray R2. In one example, the ray R1 may be rotationally spaced about the drive axis <NUM> from the ray R2 by an angle α such that the cutting engagement between the cutting features <NUM> and the cutting hub <NUM> may be adapted to accommodate application-specific requirements by, for instance, altering the angle α (and/or the contour of the cutting arm <NUM>) to adjust the cyclical timing of the cutting engagement.

As shown in <FIG>, <FIG> the axial cutting action between the cutting plate <NUM> and the cutting hub <NUM> can be generally accomplished as axial cutting arms <NUM> of the cutting hub <NUM> rotate adjacent to the pair of cutting edges <NUM> in two separate cutting actions (e.g., a scissor-type, shearing action and a chipping-type action). For example, as the cutting hub <NUM> is rotated and one of the axial cutting arms <NUM> passes over one of the cutting features <NUM>, the leading edge <NUM> of the cutting arm <NUM> first passes over the radially inner cutting edge <NUM> (see, e.g., <FIG>). As the leading edge <NUM> passes over the radially inner cutting edge <NUM>, a scissor-type, shearing action occurs between the leading edge <NUM> and the radially inner cutting edge <NUM> due to the arrangement of the cutting feature <NUM> with respect to the cutting arm <NUM> (see, e.g., <FIG>). Specifically, the cutting feature <NUM> is arranged such that, as the cutting hub <NUM> rotates, the convex shape of the trailing sidewall <NUM>, the convex shape of the leading edge <NUM> of the cutting arm <NUM>, and the angle α between ray R1 and ray R2 provides that a majority of the radially inner cutting edge <NUM> is arranged close to parallel to the leading edge <NUM> of the cutting arm <NUM>. With the close to parallel arrangement between the radially inner cutting edge <NUM> and the leading edge <NUM>, the leading edge <NUM> gradually shears over the radially inner cutting edge <NUM>.

Conversely, the cutting feature <NUM> is arranged such that, as the cutting hub <NUM> rotates, a majority of the radially outer cutting edge <NUM> may be arranged close to perpendicular, with only a radially outermost portion of the radially outer cutting edge <NUM> being disposed at or near parallel to the leading edge <NUM> of the cutting arm <NUM>. As such, the leading edge <NUM> may shear over the portion of the radially outer cutting edge <NUM> that is close to perpendicular to the leading edge <NUM>, and then abruptly passes over the end portion of the radially outer cutting edge <NUM> that is close to parallel with the leading edge <NUM> (see, e.g., <FIG>). The abrupt change in relative angles between the radially outer cutting edge <NUM> and the leading edge <NUM> may result in a chipping-type cutting action. As such, the scissor-type action and the chipping-type action may establish two separate zones of cutting engagement at the pair of cutting edges <NUM> as the cutting hub <NUM> rotates relative to the cutting plate <NUM>.

The cutting hub <NUM> may include three circumferentially-spaced axial cutting arms <NUM> that may extend radially outward from a central, cylindrical hub portion <NUM>. Each of the axial cutting arms <NUM> of the cutting hub <NUM> may have a leading edge <NUM> that is positioned adjacent to the front axial surface <NUM> of the cutting plate <NUM>. As the cutting hub <NUM> rotates, the leading edges <NUM> of each axial cutting arm <NUM> may shear past the fixed pair of cutting edges <NUM> of the cutting features <NUM> of the cutting plate <NUM>.

In some instances, the arrangement of the cutting features <NUM> on the cutting plate <NUM> and the spacing between the cutting arms <NUM> of the cutting hub <NUM> ensure that only one cutting arm <NUM> and one cutting feature <NUM> are performing a cutting action at any given time. This may allow for a more uniform torque on the pump motor, while also reducing starting torque on the pump motor in the case that debris is disposed between the cutting arm <NUM> and the cutting feature <NUM> when the pump motor is started.

As shown in <FIG>, a gap or spacing <NUM> between the leading edge <NUM> and the front axial surface <NUM> can be adjusted based on the particular application requirements, such as desired axial cut size and medium being processed. For example, in some instances, the gap or spacing <NUM> may be less than <NUM>.

As shown in <FIG> and <FIG>, each of the axial cutting arms <NUM> may taper from a wider and thicker base portion <NUM> adjacent the hub portion <NUM> to a narrower and thinner tip portion <NUM> at a distal end of the axial cutting arm <NUM>. Each axial cutting arm <NUM> may have a generally arcuate front surface <NUM> and a generally planar rear surface <NUM>. The front surface <NUM> may be rounded to aid in rejecting suspended debris that has not been sufficiently reduced in size by the axial cutting action. An undercut 74may be formed in the rear surface <NUM> to create a low pressure zone on the back edge <NUM> of the axial cutting arm <NUM> to help prevent debris from being trapped or becoming stagnant as the axial cutting arm <NUM> rotates. The arcuate front surface <NUM> of the cutting arms <NUM> may also minimize the magnitude of a torque spike of the motor when debris comes into abrupt contact with the cutting hub <NUM>.

The cutting hub <NUM> may further include a connection cap recess <NUM>, a plate engagement portion <NUM> (shown in <FIG> and <FIG>), and a plurality of deflection fins <NUM>. The connection cap recess <NUM> may be recessed into a front surface <NUM> of the hub portion <NUM>. The connection cap recess <NUM> may be configured to receive and/or engage a corresponding connection cap (not shown) that is configured to engage the drive shaft of the motor to lock the cutting hub <NUM> into engagement with the cutting plate <NUM>.

The plate engagement portion <NUM> may define a generally cylindrical shape that extends away from a rear surface <NUM> of the hub portion <NUM>. The plate engagement portion <NUM> may have a diameter that corresponds to a diameter of the central opening <NUM> of the cutting plate <NUM>. As such, the plate engagement portion <NUM> may be received within the central opening <NUM> of the cutting plate <NUM>.

The plurality of deflection fins <NUM> may extend radially outward from the hub portion <NUM>, at a lower end of the hub portion <NUM>, between adjacent cutting arms <NUM>. In some instances, the rear surface of each of the deflection fins <NUM> may be flush with the rear surface <NUM> of the hub portion. As best shown in <FIG>, when the plate engagement portion <NUM> of the cutting hub <NUM> is received within the central opening <NUM> of the cutting plate <NUM>, a distal tip <NUM> of each fin <NUM> extends radially outward, past the inner ends <NUM> of the deflection features <NUM>, to approximately the inner ends <NUM> of the cutting features <NUM>. As such, the fins <NUM> are configured to urge debris away from the central opening <NUM> of the cutting plate <NUM> while the cutting hub <NUM> is rotated. Accordingly, with reference to <FIG>, the fins <NUM> are configured to aid in preventing debris from becoming lodged between the inwardly-facing radial wall <NUM> of the central opening <NUM> and an outwardly-facing radial wall <NUM> of the plate engagement portion <NUM>, which can inhibit relative rotation between the cutting plate <NUM> and the cutting hub <NUM>.

In the illustrated non-limiting example, there are three deflection fins <NUM> that may be evenly spaced around the circumference of the cutting hub <NUM>. In other embodiments, the shape, number, and relative orientation of the deflection fins <NUM> may be altered to accommodate application-specific requirements.

With reference to <FIG> and <FIG>, the cutting hub <NUM> may further include a node <NUM> that is configured to direct debris away from the drive axis <NUM>. The node <NUM> may extend axially from the front surface <NUM> of the hub portion <NUM> an axial distance D1. The node <NUM> may define a leading portion <NUM> and a trailing portion <NUM> that may be connected by an intermediate axial portion <NUM>. The intermediate axial portion <NUM> may be substantially parallel to the front surface <NUM> of the hub portion <NUM>. The node <NUM> may span a circumferential distance D2 from a leading lower corner <NUM> to a trailing lower corner <NUM>. In some instances, the circumferential distance D2 may be about three times the axial distance D1, where "about" is within <NUM>%. For example, the axial distance D1 may be about <NUM> and the circumferential distance D2 may be about <NUM>, where "about" is within <NUM>%.

In some instances, the slope/angle of the leading portion <NUM> relative to the front surface <NUM> is more gradual than that of the trailing portion <NUM>. For example, a leading angle β between the leading portion <NUM> and the front surface <NUM> of the hub portion <NUM> may be any angle between about <NUM>-<NUM> degrees, and preferably about <NUM> degrees, where "about" is within <NUM>%. As another example, a trailing angle γ between the trailing portion <NUM> and the front surface <NUM> may be any angle between about <NUM>-<NUM> degrees, and preferably about <NUM> degrees, where "about" is within <NUM>%. In other exemplary embodiments, the leading angle β may greater than <NUM> degrees and the trailing angle γ may be greater than <NUM> degrees.

Further, the node <NUM> may include a leading upper corner <NUM> and a trailing upper corner <NUM>. In some instances, the leading upper corner <NUM> and the trailing upper corner <NUM> may have radii of curvature that are about three times the radii of curvature of the leading lower corner <NUM> and the trailing lower corner <NUM>, where "about" is within <NUM>%. For example, the leading upper corner <NUM> and the trailing upper corner <NUM> may each have a radius of curvature of between about <NUM>-<NUM>, and preferably about <NUM>, and the leading lower corner <NUM> and the trailing lower corner <NUM> may each have a radius of curvature of about <NUM>-<NUM>, and preferably about <NUM>, where "about" is within <NUM>%.

Referring now to <FIG>, the node <NUM> may also define an interior surface <NUM> and an exterior surface <NUM> that may both generally taper toward the intermediate axial portion <NUM>, with the exterior surface <NUM> skewed at a greater angle than the interior surface <NUM>, relative to an axial direction <NUM> of the drive axis <NUM>. For example, the exterior surface <NUM> may be arranged at an angle δ from the axial direction <NUM> and the interior surface <NUM> may be arranged at an angle ε from the axial direction <NUM>. In some instances, the angle δ may be any angle between about <NUM>-<NUM> degrees and the angle ε may be any angle between about <NUM>-<NUM> degrees, where "about" is within <NUM>% As the cutting hub <NUM> rotates, the node <NUM> may be configured to deflect and reject debris away from the drive axis <NUM> and toward the various cutting features <NUM>. With this node <NUM> form factor (e.g., elevation/cam profile), debris (e.g., cloths, wipes, etc.) that will otherwise surround the cutting rotor during suction, are preferably diverted and fed, for instance, step-by-step to the cutting features. This helps enable a more continuous cutting process without longer undercuts and reduced potential for excessive loading. In addition, the flow-optimized geometry of these node <NUM> features reduces and limits power loss during operation.

In the illustrated non-limiting example, there may be a single node <NUM> extending from the hub portion <NUM>. In other embodiments, the placement, shape, number, and relative orientation of the node <NUM> may be altered to accommodate application-specific requirements.

Once the axial cutting action is complete, the resulting slurry may be urged by the rotating impeller of the fluid pump, through the internal manifold, toward the outlet of the pump housing The illustrated construction of the cutting plate <NUM> and the cutting hub <NUM> (as shown in <FIG>) provides a generally constant inlet area that improves the efficiency of the overall cutting blade application. For instance, the cross sectional area of the central opening <NUM> in the cutting plate <NUM> may be generally constant over the axial length of the central opening <NUM>. The relatively constant inlet area minimizes the velocity changes of the fluid/slurry as it travels through the cutting blade assembly <NUM> and associated pump components. In the cutting blade assembly <NUM>, the fluid speed may be increased as it passes into and through the cutting features <NUM>, reduces slightly downstream of the cutting features <NUM>, and maintains approximately the same velocity before reaching the impeller. The torque required to operate the cutting blade assembly <NUM> may be further minimized by the swept back configuration of the axial cutting arms <NUM>. Furthermore, the cutting configuration employed in the axial cutting action may reduce the torque requirements as compared to a conventional cutting action. The reduction in typical cut size achieved by having two separate cutting edges <NUM> for each cutting feature <NUM> may also reduce the torque required.

Claim 1:
A cutting blade assembly (<NUM>) operably coupleable to a fluid pump, the cutting blade assembly comprising:
a cutting plate (<NUM>) having a front axial surface (<NUM>), an opening (<NUM>), and a plurality of cutting holes, each of the plurality of cutting holes defining at least one cutting edge (<NUM>);
a cutting hub (<NUM>) disposed at least partially within the opening of the cutting plate and having a cutting arm (<NUM>) and a fin (<NUM>), the cutting arm being adjacent to the front axial surface and defining an arcuate front surface (<NUM>) having a leading edge, the fin being adjacent to the front axial surface and proximate to the cutting arm; and
a plurality of deflection features (<NUM>), each deflection feature including an inner end (<NUM>) proximate the opening and an outer end (<NUM>) at a radial edge (<NUM>) of the cutting plate (<NUM>), wherein each of the deflection features (<NUM>) gradually widens from the inner end (<NUM>) to the outer end (<NUM>), wherein the plurality of deflection features (<NUM>) are configured to deflect debris radially outward away from the opening (<NUM>) when the cutting hub (<NUM>) is rotated relative to the cutting plate (<NUM>);
wherein, when the cutting plate and the cutting hub are rotated relative to each other, the leading edge (<NUM>) of the cutting arm passes adjacent to the plurality of cutting holes so that the relative rotation of the cutting plate and the cutting hub defines a cutting action between the leading edge and the at least one cutting edge, and the fin is configured to urge debris away from the opening of the cutting plate.