WO2019006048A1

WO2019006048A1 - Rotatable blade with replaceable cutting edges

Info

Publication number: WO2019006048A1
Application number: PCT/US2018/039881
Authority: WO
Inventors: Patrick PUNTONI
Original assignee: Pbs Puntoni Business Solutions Llc
Priority date: 2017-06-28
Filing date: 2018-06-28
Publication date: 2019-01-03

Abstract

The present disclosure provides rotatable blades with easily replaceable cutting edges, and methods of making and using same.

Description

ROTATABLE BLADE WITH REPLACEABLE CUTTING EDGES Priority Claim

This application claims priority to U.S. Provisional Patent Application Serial No.

62/525,847; filed on June 28, 2017, the entire contents of which are incorporated herein by reference and relied upon.

Background

Rotatabie blades used on mowers and other cutting machines are generally made from a single piece with the rotatabie blade having one or more section of the rotatabie blade sharpened to form a cutting edge to perform the cutting action that the rotatabie blade was designed to do. The cutting edges on rotatabie blades used on mowers and other cutting machines are considered a wear area and require routine sharpening. Single- piece rotatabie blades can also lose shape, dimension, and balance due to material removal after multiple resharpenings which can change the operating performance after sharpening when compared to when it was new. Sharpening rotatabie blade cutting edges usually requires removal and re-installation of the entire rotatabie blade from the cutting machine. This process can be considerably difficult to do and can require a lot of time and effort, and can be dangerous. The time requirements and the cost incurred to either sharpen or replace the entire rotatabie blade can be substantial. Known rotatabie blades with replaceable cutting edges do not enable efficient and economical use due to their complexity. Special processes or tooling is generally required, which significantly limits their utility.

A need persists for improved rotatabie blades with convenient and economical replaceable cutting edges. Summary

The present disclosure provides rotatabie cutting blades with replaceable cutting edges that can withstand the same forces and loads encountered by a single-piece rotatabie cutting blade, can easily be replaced, and be economically feasible to replace the cutting edges without having to replace the entire rotatabie blade or dismount the rotatable blade for sharpening. Devices consistent with this disclosure allow for quick and economical replacement of cutting edges but has the flexibility to be used and is adaptable for the many different rotatable blade design configurations currently used in the marketplace. The replaceable cutting edges can be easily separated during the replacement procedure by using a tool or wedge to pry the replaceable cutting edges loose from the cutting blade assembly using the aligned cutouts in both the retainer bracket and replaceable cutting edge. The aligned cutouts in the retainer bracket and the replaceable cutting edge also provide a relief outlet for any loose debris that could collect in the rotatable blade finger slots during the installation process. Said replacement cutting edges can only be assembled one way to promote safety during replacement and operation.

!n some embodiments, the present disclosure provides a rotatable blade comprising a blade body having an axis of rotation, a first long edge, a second long edge opposite the first long edge, a first end portion, and a second end portion opposite the first end from the axis of rotation; and a first cutting edge removably associated with the first long edge and the first end portion.

In some embodiments, the present disclosure provides a method of improving performance of a rotatable cutting blade, the method comprising: un-mating the replaceable cutting edge(s) from the blade body; and mating new or re-sharpened replaceable cutting edge(s) to the blade body.

These and other objects of the present technology will become readily apparent upon further review of the following detailed description, examples, and drawings.

Fig, 1 shows a perspective view of a portion of a rotatable blade including replaceable cutting edges according to one embodiment of the present disclosure.

Fig. 1 A shows a top plan view of the rotating blade of Fig. 1 including two generally opposed replaceable cutting edges.

Fig. 2 shows an exploded perspective view of a portion of a rotatable blade including a replaceable cutting edge and associated retainer bracket according to one embodiment of the present disclosure. Fig. 3A shows a perspective view of a portion of a rotatable blade including a replaceable cutting edge and associated retainer bracket and replaceable cutting edge retainer bracket according to one embodiment of the present disclosure.

Fig. 3B shows a plan side view of a replaceable cutting edge retainer bracket according to one embodiment of the present disclosure.

Fig. 4A shows a plan side view of a rotatable blade including a replaceable cutting edge and associated replaceable cutting edge retainer bracket according to one embodiment of the present disclosure.

Fig, 4B shows a plan side view of a rotatable blade including an aerodynamic wing portion and a replaceable cutting edge and associated replaceable cutting edge retainer bracket according to one embodiment of the present disclosure.

Fig. 4C shows a plan side view of a rotatable blade including a replaceable cutting edge and an associated retainer bracket including an aerodynamic wing portion according to one embodiment of the present disclosure. Fig. 5 shows an exploded perspective view of a portion of a rotatable blade including an aerodynamic wing portion and an associated replaceable cutting edge and retainer bracket according to one embodiment of the present disclosure.

Fig. 6 shows an exploded perspective view of a portion of a rotatable blade, an associated replaceable cutting edge, and an associated retainer bracket including an aerodynamic wing according to one embodiment of the present disclosure.

Fig. 7A shows a plan top view of a replaceable cutting edge including a bend line according to one embodiment of the present disclosure.

Fig. 7B shows a plan side view of the rotatable blade and associated replaceable cutting edge and retainer bracket of Fig. 7A. Fig. 8 shows a plan top view of a rotatable blade including two generally opposed replaceable cutting edges according to one embodiment of the present invention.

Fig, 9 shows a perspective view of a portion of a rotatable blade including a

replaceable aerodynamic wing and replaceable cutting edge wherein the leading edge has an area equal to or larger than the assembled thickness of the rotatable blade assembly according to one embodiment of the present disclosure.

Fig, 10 shows an exploded perspective view of the embodiment shown in Fig, 9.

Fig, 10A shows a plan side view of one end of a replaceable aerodynamic wing and its attaching hardware according to one embodiment of the present disclosure.

Fig. 10B shows a plan side view of a replaceable cutting edge retainer bracket and associated retaining pin according to one embodiment of the present disclosure.

Fig. 10C shows a plan side view of a rotatable blade assembly including a replaceable aerodynamic wing and associated retainer brackets wherein the leading edge has an area equal to or larger than the assembled thickness of the rotatable blade assembly according to one embodiment of the present disclosure.

Rotatable blades consistent with the present disclosure generally feature one or more replaceable cutting edges that mate with a rotatable blade body portion via an interlocking finger-like pattern. Such a design enables mating of replaceable cutting edge(s) with the rotatable blade body in a manner that minimizes or even prevents lateral shift of the replaceable cutting edge portion relative to the rotatable blade body portion during operation (e.g., in response to centrifugal forces).

The replaceable cutting edges can also be made of special material that is different than the rotatable blades, such as material with a higher Rockwell number than the rotatable blade material, to improve the wearability and service life of the replaceable cutting edges.

In some embodiments, a rotatable blade consistent with the present disclosure includes a single replaceable cutting edge. One or more of such rotatable blades may be attached about a circular mounting device to form a "flail" type blade assembly. In other embodiments, a rotatable blade consistent with the present disclosure includes two replaceable cutting edges separated by a mounting hole/axis of rotation. In other embodiments, a rotatable blade consistent with the present disclosure includes multiple replaceable cutting edges, each cutting edge disposed on one of multiple blade body sections, with each of the multiple blade body sections sharing a single common axis of rotation. In some embodiments, a rotatabie blade consistent with the present disclosure includes n replaceable cutting edges, each cutting edge disposed on one of n blade body sections, with each of the n blade body sections sharing a single common axis of rotation.

Fig. 1 shows one end of the assembly of the rotatabie blade 1 with the replaceable cutting edge 2 held in place by the retainer bracket 3 which is bolted to the rotating blade 1 by attachment bolts 20 and nuts 21 . The replaceable cutting edge retainer bracket spring 9 is held in place on top of the retainer bracket 3 by the bolt 20 and nut 21 in the center hole of the retainer bracket 3. The blade assembly rotates clockwise around the center axis and mounting hole 27.

Fig. 1A shows a top view of a rotatabie blade 1 with replaceable cutting edges separated at both ends that rotates clockwise 17 around the axis of the rotating blade mounting hole 27 with the replaceable cutting edges 2 separated to illustrate how the outwardly angled slot pattern 6 formed on the rotatabie blade 1 are angled in the direction of centrifugal force 18 to match up and mate with the outwardly angled finger pattern 5 formed on the replaceable cutting edges 2 angled in the same direction of centrifugal force 18. When the replaceable cutting edge 2 are slid together in the direction of the arrows where the two pieces are touching the rotatabie blade 1 they together form one integral body like an individual piece of a jig-saw puzzle holds together with the cut pattern of the other touching pieces of the jig-saw puzzle to form a single piece of the entire jig-saw puzzle. When slid together the outwardly angled finger pattern 5 on the replaceable cutting edges 2 mesh with the outwardly angled slot pattern 6 of the rotatabie blade 1 to form a closely spaced union tightly held together under centrifugal force 18 created as the rotatabie blade 1 rotates around the axis of the rotatabie blade mounting hole 27. Replaceable cutting edges 2 used on certain designs of rotatabie blades 1 may require an extension of the angled slot pattern 6 and finger pattern 5 that serves the same purpose and intent of said invention to accommodate longer or larger sizes of replaceable cutting edges 2. The simple pattern of the replaceable cutting edges 2 allows for the simple and economical manufacturing of the replaceable cutting edges 2 out of material that is similar in dimension and shape to the shape and area on the outside leading edges of the rotafable blade 1 . Said replaceable cutting edges 2 are easy to manufacture without special tooling or a special

manufacturing process can be made from the same material that the rotatable blade 1 is made from that allow for them to be produced in quantities that make their

replacement economically feasible. The material composition of the replaceable cutting edges 2 may differ from the material composition of the rotatable blade 1 in order to have the replaceable cutting tips 2 made of a material that improves wear and durability. This pattern allows for this instant invention to be adaptable to work in many different rotating blade design and dimensional configurations currently used in the marketplace today for rotating blades today. Fig. 1A shows an embodiment wherein the rotatable blade 1 rotates in a clockwise direction 17. This instant invention is just as applicable to a rotating blade that turns in a counterclockwise direction by just reversing the clockwise directional sensitive design features and description criteria that are readily known by any person of ordinary skill in the pertinent art, science, area to accommodate the counterclockwise direction of a rotating blade intended to be used for the same objective of this invention. The retainer bracket notch 14 cut into the outside leading tip of the rotatable blade 1 provides a recess in the rotating bade where the retainer bracket 3 wraps around the rotating blade and prevents the retainer bracket 3 from extending past the outside edge of the rotatable blade 1. Fig. 2 shows an embodiment of one end of a rotatable blade 1 that rotates in a clockwise direction with the replaceable cutting edge 2, the retainer bracket 3, attachment bolts 20, and the attachment nuts 21 separated for illustration on the outside leading edge of the rotatable blade 1 . The mounting holes 4 in both the rotatable blade 1 and the retainer bracket 3 are for the attachment of the retainer bracket 3 to the rotatable blade 1 by the bolts 20 and the nuts 21 as shown in Fig. 1 . The holes 1 1 in the retainer bracket 3 and the repiaceable cutting edges 2 accommodate the retainer pins 10 on the replaceable cutting edge retainer bracket spring 9 shown in Fig. 3A and Fig. 3B. The retainer pins 10 on the replaceable cutting edge retainer bracket provide retention of the repiaceable cutting edges 2 to the retainer bracket 3 when assembles as shown in Fig. 3A. The retainer bracket notch 14 in the rotatable blade 1 is to accommodate the placement of the retainer bracket end section 15. The angled cutout 18 allows for a replaceable cutting edge 2 to rest against the retainer bracket end section 15 when ail pieces are assembled as shown in Fig. 1 . This allows for the retainer bracket end section 15 to act as a spacer to provide support for the replaceable cutting edges 2 to rest against and contacts the rotatable blade 1 so ail together they are touching each other as contiguous pieces. When all pieces are assembled as shown in Fig, 1 the perpendicular to travel mating surfaces 7 on the replaceable cutting edge 2 rest squarely against the perpendicular to travel mating surfaces 8 on the rotatable blade 1 , This mating joint surface provides strength and allows the replaceable cutting edge 2 to butt up to the rotating blade 2 forming contiguous pieces allowing for the transfer of the forces acting on the replaceable cutting edge 2 from the direction of rotation between the replaceable cutting edge 2 and the rotatable blade 1. When the pieces are all assembled together as shown in Fig. 1 the assembled body is bonded together with strength comparable to a single piece rotating blade without replaceable cutting edges. When the replaceable cutting edges 2 are slid together with the rotatable blade 1 they become contiguous pieces with tight tolerances between the mating surfaces where debris and corrosion can form between the joints of the adjoining pieces that can make separation difficult. Cutouts 12 on the angled fingers of the replaceable cutting edges 2 and cutouts 13 on the retainer bracket 3 are in alignment vertically and horizontally with each other when the retainer bracket 3 and the replaceable cutting edge 2 are assembled together as shown in Fig. 1 . Cutouts 13 in the retainer bracket 3 and cutouts 12 in the replaceable cutting edge 2 provide access so a prying tool or wedge can be used to aid in separation of the replaceable cutting edge 2 from the rotatable blade 1 during servicing. Cutouts 13 in the retainer bracket 3 and the cutouts 12 in the replaceable cutting edge also provide an outlet relief for any debris that could be in the socket area formed when the retainer bracket 3 is installed on the rotatable blade 1 as shown in Fig. 3 A.

Fig, 3A shows an assembly drawing of one end of a rotatable blade 1 that rotates in a clockwise direction with the retainer bracket 3 is positioned on the rotatable blade 1 , The retainer bracket 3 wraps around the leading edge of the outside tip of the rotatable blade 1 with the retainer bracket end section 15 located in the retainer bracket notch 14 (shown in Fig. 2) where the retainer bracket end section 15 recesses inwardly into the body of the rotatable blade 1 so the retainer bracket end section 15 does not extend beyond the outside edge of the rotatable blade 1 . The combination of the retainer bracket 3 and the blade 1 form one or more sockets 1 s into which the one or more fingers 5 of the cutting edge 2 may be inserted. The angled cut edges 16 in the retainer bracket 3 allows the back side of the outer tip of the tapered cutting edge 24 to rest on the retainer bracket end section 15 with the outer tip of the replaceable cutting edge 2 flush with the outside edge of the rotatabie blade 1 and not extend past the outside edge of the rotatabie blade 1 as shown in Fig. 1. Mounting holes 4 in both the retainer bracket 3 and rotatabie blade 1 allow for the retainer bracket to be fastened to the rotatabie blade 1 by using attachment bolts 20 and nuts 21 . Retainer bracket 3 can also secured to the rotatabie blade 1 by many other methods used in manufacturing other than using the bolts 20 or nuts 21 shown in these drawings. For example, the retainer bracket 3 could also be attached to the rotatabie blade 1 by rivets, different types of bolts, different types of nuts, welding the retaining bracket 3 to the rotatabie blade 1 , or by casting a rotatabie blade with a socket that could duplicate the concept of said invention. Due to the corrosive operating environment rotating cutting blades encounter consideration should be given to either coating the retainer bracket 3 with anti-corrosive material or making the retainer bracket 3 out of anti-corrosive material like stainless steel. When the retainer bracket 3 is installed on the rotatabie blade 1 as illustrated in Fig. 3A the retainer bracket 3 bridges across the outwardly angled slots (6 in Fig. 1 A) in the rotatabie blade 1 and creates a socket that accommodates the angled fingers (5 in Fig. 1 A) when the replaceable cutting edge is slid together as shown in Fig. 1 . This socket area also has an overlap area 19 that overlaps the longitude area of the replaceable cutting edge 2 in the area horizontal to the back side of the tapered cutting edge 24. The bridging of the retainer bracket 3 across the slots (6 in Fig. 1 A) sandwiches the replaceable cutting edge 2 between the upper and lower retainer bracket 3 as shown in Fig. 1. The socket area shown in Fig. 3A also allows for the replaceable cutting edges 2 to be made in a manner where they are easy to manufacture without special tooling or a special manufacturing process. !n some embodiments, the replaceable cutting edges 2 are made from the same material as the rotatabie blade 1 . In other embodiments, the material composition of the replaceable cutting edges 2 differs from the material composition of the rotatable blade 1 in order to have the replaceable cutting edges 2 made of a material that improves wear and durability. When assembled together as shown in Fig. 1 the mating surface of the replaceable cutting edge 7 rest squarely against the mating surface of the rotating blade 8 forming a contiguous piece between the rotatable blade 1 and the replaceable cutting edge 2. When assembled together as shown in Fig. 1 this socket configuration, overlap area 19, mating of the cutting edge surfaces 7, and mating of rotating blade surfaces 8 form a strong retainer that bonds the rotatable blade 1 , retainer bracket 3, and the replaceable cutting edges 2 securely in place and provides the strength and support where the replaceable cutting edge 2 is retained in a sandwich position duplicating as close as possible a the strength and support of a single piece rotating blade that does not have replaceable cutting edges. To help secure the replaceable cutting edge in place, to ensure safety, and to prevent the replaceable cutting edge from an unintended separation from the retaining socket the replaceable cutting edge retainer bracket spring 9 is installed directly on top of the retainer bracket 3 and is secured in place by the center bolt 20 and nut 22 in the retainer bracket 3 as shown in Fig. 1. The replaceable edge retainer bracket spring 9 has two retaining pins 10 that protrude through the pin holes 1 1 in the retainer bracket 3 and thru the pin holes 1 1 in the replaceable cutting edge 2 to hold the replaceable cutting edge 2 securely in place during operation. Cutouts 13 in the retainer bracket 3 and cutouts 12 in the replaceable cutting edge 2 provide access so a prying tool or wedge can be used to aid in separation of the replaceable cutting edge 2 from the rotatable blade 1 . Cutouts 12 on the angled fingers of the replaceable cutting edges 2 and cutouts 13 on the retainer bracket 3 are in alignment vertically and horizontally with each other when the retainer bracket 3 and the replaceable cutting edge 2 are assembled together as shown in Fig. 1 . Cutouts 13 in the retainer bracket 3 and cutouts 12 in the replaceable cutting edge 2 provide access so a prying tool or wedge can be used to aid in separation of the replaceable cutting edge 2 from the rotatable blade 1 during servicing. Cutouts 13 in the retainer bracket 3 and the cutouts 12 in the replaceable cutting edge 2 also provide an outlet relief for any debris that could be in the socket area formed when the retainer bracket 3 is installed on the rotatabie blade 1 as shown in Fig.

3A,

Fig, 3B shows an end view of the replaceable cutting edge retainer bracket spring 9 and the retaining pins 10 that are part of the bracket Fig. 4A shows the end view of the assembled flat clockwise rotatabie blade shown in Fig. 1 . The retainer bracket 3 is assembled over the rotatabie blade 1 with the replaceable cutting edge 2 slid against the rotatabie blade 1 and sandwiched between the upper and lower portion of the retainer bracket 3 with the retainer bracket overlap 19 extending past the back edge of the replaceable cutting edge. Fig. 4B shows the end view of an assembled rotatabie blade 1 shown in Fig. 5 with a bend line 22 put on the rotatabie blade 1 forming a wing tip on the rotatabie blade 1 to promote aerodynamic action in addition to cutting from the rotatabie blade 1 . The retainer bracket 3 is assembled over the rotatabie blade 1 with the replaceable cutting edge 2 slid against the rotatabie blade 1 and sandwiched between the upper and lower portion of the retainer bracket 3 with the retainer bracket overlap 19 extending past the back edge of the replaceable cutting edge 2. There is an abundant number of rotating cutting blades in the marketplace that are bent with wing tips formed and shaped to provide aerodynamic action in addition to cutting action. This view shows the flexibility of the said invention used on rotatabie blades 1 that are bent, twisted, or shaped to provide aerodynamic functions in addition to cutting. Inventions of prior art replaceable cutting tip designs cannot be feasibly used with many blade configurations that have the rotating blade bent to form an aerodynamic wing.

Fig, 4C shows the end view of a fiat clockwise rotating blade shown in Fig, 6 with a bend line 23 put on the retainer bracket 3 to promote aerodynamic action in addition to cutting action from the rotatabie blade 1 using the retainer bracket 3 to provide the function rather than a bend on the rotatabie blade 1 like is shown in Fig. 4B. The retainer bracket 3 is assembled over the rotatabie blade 1 with the replaceable cutting edge 2 slid against the rotatabie blade 1 and sandwiched between the upper and lower portion of the retainer bracket 3 with the retainer bracket overlap 19 extending past the back edge of the replaceable cutting edge. This view also shows the flexibility of the said invention by having an option to produce a retainer bracket 3 with a slight variation where the retainer bracket 3 is bent across a bend line 23 and used as an alternative design to a rotating blade that is bent like the blade that is shown in Fig. 4B to provide aerodynamic functions in addition to cutting. This embodiment may be able to be produced at a substantially lower cost compared to a rotatable cutting blade that is bent to provide the same purpose.

Fig. 5 shows an alternative assembly drawing of one end of a clockwise rotatable blade 1 that has a bend line 22 across the outer tip of the rotatable blade 1 to provide aerodynamic functions by the rotatable blade 1 in addition to cutting. With the exception of the bend line 22 all other illustrations and features in Fig. 5 are identical in scope and purpose to the rotatable blade 1 , replaceable cutting edge 2, bolts 20, nuts 21 , and retainer bracket 3 described in the detailed description of Fig. 2. Fig. 4B shows an end view of this assembled combination. This illustration further shows the adaptability to said invention to many different rotating blade designs.

Fig. 6 shows an alternative assembly drawing of one end of a clockwise rotatable blade 1 where the top section of retainer bracket 3 is different from the other illustrations in that it is made larger allowing for a portion of the upper section of the retainer bracket 3 to be bent along a bend line 23 to provide aerodynamic function in addition to cutting. The end view of this assembled blade is shown in Fig. 4C. The extra area of material used to make a larger upper portion of the retainer bracket 3 that make the upper section of the retainer bracket wider and the modification to the shape and size to the notches 13 to compensate for the addition of extra area of material on the top section of the retainer bracket 3 are the only differences in the retainer bracket 3 shown in this drawing and in Fig. 4C when compared to the other retainer brackets 3 shown in ail other embodiment drawings. The extra material to make the top section of the retainer bracket 3 bigger is needed to overlay the outer tip of the rotatable blade 1 opposite the replaceable cutting edge 2 as shown in Fig. 4C and to have enough area where the retainer bracket 3 can be bent upward along the bend line 23 to form a wing tip with the purpose to provide aerodynamic function along with the cutting action for the

assembled rotating blade embodiment. The shape and size of the notches 13 are enlarged on this style of retainer bracket 3 to allow the access of a tool or wedge to pry the replaceable cutting edge loose during the removal process and provide an relief outlet for any debris that could collect in the sockets formed by the retainer bracket 3 when installed on the rotatabie blade 1 assemble as shown in Fig, 1 , This is an optiona way to manufacture the retainer bracket 3 and use the said invention replaceable cutting edge 2 with some versatility to incorporate some features that would normally be used on the rotating blade 3 as shown in Fig, 5, The versatility of usage with many different rotating designs is a distinct advantage of said invention over prior art.

Fig, 7A shows a top view of the replaceable cutting edge 2 that is downward bent as shown in Fig. 7B and shows the location of the replaceable cutting edge bend line 28 that is used to make the bend horizontally behind the tapered cutting edge 24 to make the replaceable cutting edge 2 cut below the bottom of the retainer bracket 3 as shown in Fig. 7B. This illustration is to assist in explaining the design and purpose of the alternative design of the downward bent cutting edge 25 shown in Fig, 7B.

Fig, 7B shows a side view of an alternate way to manufacture the replaceable cutting edge that would rotate in a clockwise direction with a downward bent replaceable cutting edge 25 instead of using a flat replaceable cutting edge 2 as shown Fig, 4A, The downward bent replaceable cutting edge 25 lowers the cut line 28 to where the material being cut by the rotatabie blade 1 would be below the lower edge of the retainer bracket 3. The downward bent replaceable cutting edge 25 fits into the socket created by the retainer bracket 3, has the same retainer bracket overlap 19, and butts up to the rotatabie blade 1 the same as a flat replaceable cutting edge does as shown in Fig. 4A. This may be an alternate design to a flat replaceable cutting edge as shown in Fig. 4A and favorable to use in operating conditions where the bottom portion of the retainer bracket would be above the cut line 28 of the material being cut. In this embodiment, the replaceable cutting edge 2 includes a tapered cutting edge 24 that extends downwardly so the cut line 28 of the material being cut is below the bottom of the retainer bracket 3.

Fig, 8 show a top view of an alternate design of a rotatabie blade 1 that rotates in a clockwise direction 17 and has a different design of replaceable cutting edges 2. This design was considered and could be used as an alternative to the design of said invention as shown in Fig, 1A, The design shown in Fig. 1A has the advantage of being stronger due to the additional support provided by the middle mounting hole for the retainer bracket and has better retention due to centrifugal force due to the angled slot and finger pattern shown in Fig. 1A.

In some embodiments, the retainer bracket 3 of a rotatabie blade 1 with replaceable cutting edges 2 otherwise consistent with Figs. 1 -8 is recessed such that its top surface 3t is at or below the level of the top surface 2t of the replaceable cutting edge 2, and such that its bottom edge 3b is at or above the bottom surface 2b of the replaceable cutting edge 2.

Referring now to Figs. 9-10C. an embodiment of the present disclosure comprises a rotatabie blade body 101 including a mounting hole/ axis of rotation 127. and a replaceable cutting edge 102 removably secured to the rotatabie blade body 101 by a retainer bracket 103 and a retaining pin 109, and a replaceable aerodynamic wing 129 near one end of the rotatabie blade body 101 . In such embodiments, at least a portion of the leading edge 103e of the retainer bracket 103, such as a substantial portion of the leading edge 103e, may be at the same level as, or below, the front edge 102e of the replaceable cutting edge 102. Although not depicted explicitly, a second replaceable cutting edge 102 may be held in place on the opposite end and on the opposite long edge of the rotatabie blade body 101 from the replaceable cutting edge 102 shown in Fig. 9 by a second retainer bracket 103 and a second retaining pin 1 10. A second replaceable aerodynamic wing 129 may also be disposed on the opposite end of the rotatabie blade body 101 from the second replaceable aerodynamic wing 129 shown in Fig. 9. Alternatively, a rotatabie blade body 101 consistent with the present disclosure may have a single replaceable cutting edge 102 removably secured to the rotatabie blade body 101 by a retainer bracket 103 and a retaining pin 1 10, and a replaceable aerodynamic wing 129 near one end of the rotatabie blade body 101 , As shown in Fig, 10, rotatabie blade body 101 includes at least one mating surface 108 with a contour that is complementary to mating surface 102e' of the replaceable cutting edge 102. In some embodiments, the contour of the mating surface 108 includes one or more slots that are not perpendicular to the long edge of the rotatabie blade body 101 . For example, as shown in Fig. 10, the contour of the mating surface 108 includes two slots that are angled away from the mounting hole/axis of rotation 12 . Such a configuration provides stability to the assembled rotatable blade body 101 and replaceable cutting edge 102 to the forces imparted by high speed rotation.

A retainer bracket 103 removably secures the replaceable cutting edge 102 to the rotatable blade body 101 . In some embodiments, such as the embodiment shown in Fig. 10, the retainer bracket 103 may include a top retaining bracket portion 103a and a bottom retaining bracket portion 103b. Each of the top retaining bracket portion 103a and the bottom retaining bracket portion 103b may include one or more mounting holes 104 to accommodate one or more bolts or pins (not shown) for fastening the top retaining bracket portion 103a and the bottom retaining bracket portion 103b. In some embodiments, the one or more mounting holes 104 accommodate a rivet, a plug weld, or similar feature that attaches the top retaining bracket portion 103a and/or the bottom retaining bracket portion 103b to the rotatable blade body 101 . In some embodiments, securing the top retaining bracket portion 103a and the bottom retaining bracket portion 103b using low-profile or no-profile fasteners (e.g., rivets or plug welds) instead of bolts and nuts is advantageous to improve the quality of cut and blade performance (e.g., "tearing," "streaking," etc.) in use, possibly due to decreased turbulence around the rotatable blade body 101 during operation.

Each of the top retaining bracket portion 103a and the bottom retaining bracket portion 103b may include one or more cutout holes 1 13 to ease release of the top retaining bracket portion 103a and/or the bottom retaining bracket portion 103b from the top retaining bracket portion 103a and/or the bottom retaining bracket portion 103b, for example after a period of use. Similarly, the one or more cutout holes 1 13 may ease release of the replaceable cutting edge 102 from the rotatable blade body 101 , for example after a period of use. For example and without limitation, the one or more cutout holes 1 13 may be sized to accommodate a pry tool, such as a ¼ x 4 flathead screwdriver tip, which may be used to pry the top retaining bracket portion 103a or the bottom retaining bracket portion 103b from the rotatable blade body 101 , and/or to pry the rear edge 102e' of the replaceable cutting edge 102 from the mating surface 108 of the rotatable blade body 101 . The replaceable cutting edge 102 includes a pin hole 1 1 1 that aligns with pin holes 1 1 1 in the top retaining bracket portion103a and the bottom retaining bracket poriion103b. A retaining pin 109 includes a post 1 10 that mates with the aligned pin holes 1 1 1 to removably secure the replaceable cutting edge 102, the top retaining bracket portion 103a and the bottom retaining bracket portion 103b to the rotatabie blade body 101 . For example, as shown in Figs. 9-10C, the retaining pin 109 also protects a portion of the leading edges 103e of the top retaining bracket portion 103a and the bottom retaining bracket portion 103b. A cotter pin 131 or similar removable locking mechanism secures the retaining pin 109 in place.

In some embodiments, a replaceable aerodynamic wing 129 is removably mounted to the rotatabie blade body 101 . The replaceable aerodynamic wing 129 may feature any suitable shape. In the embodiment shown in Figs. 9-10C, for example, the replaceable aerodynamic wing 129 has a V-shaped cross section. In other

embodiments, the replaceable aerodynamic wing 129 has

One or more sets of bolts 120 and nuts 121 may be used to secure the replaceable aerodynamic wing 129 to the rotatabie blade body 101 through one or more mounting holes 104, In some embodiments, the rotatabie blade body 101 includes more mounting holes 104 than required to attach the replaceable aerodynamic wing 129 to the rotatabie blade body 101 . In such embodiments, the replaceable aerodynamic wing 129 may be attached in several alternate positions as desired by the user.

Although the replaceable aerodynamic wing 129 is shown in Figs. 9, 10 and 10C as a V-shaped piece of material, in some embodiments the replaceable aerodynamic wing 129 may be a generally wedge-shaped hollow or solid block of material, such as a plastic like ultra-high-molecular-weight polyethylene, poiytetrafluoroethyiene, acryionitrile butadiene styrene ("ABS^"), a similar durable polymer, or a combination of two or more of the foregoing. In some embodiments, the replaceable aerodynamic wing 129 has an angle Θ that ranges from about 25° to about 55°, for example about 25° to about 55°, for example about 25°, about 30°, about 35°, about 40°, about 45°, about 50°, or about 55°. In some embodiments, the replaceable aerodynamic wing 129 has a height 129b that imparts aerodynamic properties on the rotatabie blade similar to a standard lift mowing blade. In other embodiments, the replaceable aerodynamic wing 129 has a height 129h that imparts aerodynamic properties on the rotatabie blade similar to a high-lift mowing blade. In some embodiments, the replaceable aerodynamic wing 129 has a height 129h that imparts aerodynamic properties on the rotatable blade similar to a mulching blade.

Surprisingly, the thickness 103t of the top retaining bracket portion 103a and the bottom retaining bracket portion 103b is not critical for embodiments consistent with Figs. 9-10C. Instead, it has been found that embodiments wherein the leading edge 103e of the top retaining bracket portion 103a and the bottom retaining bracket portion 103b is at or even below the level of the trailing edge 102e^! of the replaceable cutting edge 102 permit the use of relatively thin gauge materials compared to the thickness 1011 of the rotatable blade body 101 . In some embodiments, the lop retaining bracket portion 103a and the bottom retaining bracket portion 103b each have a thickness 103t of about 0.025 inches (e.g., 24-gauge) to about 0 1 inches (e.g., 12-gauge), for example about 0.025 inches, about 0.03 inches, about 0.035 inches, about 0.04 inches, about 0.045 inches, about 0.05 inches, about 0.055 inches, about 0.06 inches, about 0.085 inches, about 0.07 inches, about 0.075 inches, about 0.08 inches, about 0.085 inches, about 0.09 inches, about 0.095 inches, or about 0.1 inches. In some embodiments, the rotatable blade body 101 has a thickness 1011 of about 0.125 inches to about 0.375 inches, for example about 0.125 inches, about 0.15 inches, about 0.175 inches, about 0,2 inches, about 0.225 inches, about 0.25 inches, about 0.275 inches, about 0.3 inches, about 0.325 inches, about 0.35 inches, or about 0.375 inches. In some embodiments, the top retaining bracket portion 103a and the bottom retaining bracket portion 103b each have a thickness 103t that is not more than about 50% of the thickness 1011 of the rotatable blade body 101 , for example not more than about 50%, not more than about 45%, not more than about 40%, not more than about 35%, not more than about 30%, not more than about 25%, not more than about 20%, not more than about 15%, not more than about 10%, or not more than about 5% of the thickness 1011 of the rotatable blade body 101 .

In some embodiments, the thickness 031 of the top retaining bracket portion 103a is the same as the thickness 103t of the bottom retaining bracket portion 103b. In other embodiments, the thickness 103t of the top retaining bracket portion 103a is greater than the thickness 103t of the bottom retaining bracket portion, in still other embodiments, the thickness 103t of the top retaining bracket portion 103a is less than the thickness 103t of the bottom retaining bracket portion. In one embodiment, for example as shown in Fig. 10, the replaceable cutting edge 102 includes a recessed profile portion 130 that has a smaller thickness 102r than the maximum thickness 102f of the replaceable cutting edge 102.

As shown most readily in Figs. 9, 10 and Fig. 10C, it has been surprisingly discovered that rotatable blades consistent with the present disclosure perform significantly better (e.g., provide a better quality of cut and blade performance) when the maximum thickness 102f of the replaceable cutting edge 102 is greater than or equal to the combined thickness 1011 of: the blade body 101 . the top retaining bracket 103a, and the bottom retaining bracket 103b. In some embodiments, that relationship is accomplished by including a recessed profile portion 130 at the trailing end 102e' of the replaceable cutting edge 102 such that the top retaining bracket 103a, the recessed profile portion 130, and the bottom retaining bracket 103b form a "sandwich" that has a total combined thickness 1011 that is not significantly greater than (e.g., is less than, equal to, or approximately equal to) the maximum thickness 102f of the replaceable cutting edge 102. In some embodiments, such as that shown in FIG. 10, the recessed profile portion 130 is located behind the front edge 102e of the replaceable cutting edge 102 and may extend around the one or both sides of the front edge 102e of the replaceable cutting edge 102. In other embodiments, the recessed profile portion 130 may be entirely located behind the front edge 1 Q2e of the replaceable cutting edge 102 (e.g., so that no portion of the recessed profile portion 130 is in line or nearly in line with the first long edge of the blade body 101 ). Such replaceable cutting edges 102 may be prepared by any suitable means including, for example, by removing excess material from a similar replaceable cutting edge 102 that does not include a recessed profile portion 130, by combining a relatively thick piece of material (that forms or will form the tapered cutting edge) to a relatively thin piece of material (that forms the recessed profile portion 130), or by metal casting.

In some embodiments, such as those shown in Figs. 1 , 2, 3A-6, 8-10, and 10C, the replaceable cutting edge 2/102 includes a single taper from a front-most edge toward the finger(s) 5/traiSing edge 103e\ In other embodiments, the replaceable cutting edge 2/102 includes two tapers; each originating from a shared front-most edge and sloping way from each other toward the finger(s) 5/trailing edge 103e^! (e.g., a double-tapered edge). In some embodiments, a replaceable cutting edge 2/102 including two tapers may be symmetric from top to bottom. A rotatable blade 1 /101 including one or more of such symmetric replaceable cutting edges 2/102 may be used on either a machine that causes the blade to rotate clockwise, or a machine that causes the blade to rotate counter-clockwise without significantly affecting performance.

In operation, the performance of a used rotatable blade according to the present disclosure can be efficiently improved by removing the retaining brackets 3/103 from an assembled rotatable cutting blade consistent with the present disclosure; un~mating the replaceable cutting edges 2/102 from the blade body 1/101 ; and mating new or re- sharpened replaceable cutting edges 2/102 to the blade body 1/101 . In some

embodiments, these steps can ail be performed without separating the blade body from an associated mounting apparatus, drive chain, or motor.

Example

A rotatable blade with replaceable cutting edges according to Figs. 9-10C of the present disclosure was tested using a testing protocol similar to the Blade Impact Test ("Peg Test") specified in American Society of Agricultural Engineers S474. To satisfy the ASAE S474 standard, no part of the blade may fail in a hazardous way upon insertion of a 2-inch diameter steel rod into the field of rotation while the blade is rotating at full speed (approx. 19,000 ft/min. at the blade tip).

Results of the testing are shown in Table 1 .

Table 1.

Claims

C!aims i claim:

1 . A rotatable blade comprising: a blade body having an axis of rotation, a first long edge, a second long edge opposite the first long edge, a first end portion, and a second end portion opposite the first end from the axis of rotation; and a first cutting edge removably associated with the first long edge and the first end portion.

2. The rotatable blade of Claim 1 , wherein the blade body comprises a pattern of one or more slots along the first long edge near the first end portion for removably receiving the first cutting edge.

3. The rotatable blade of Claim 2, wherein the first cutting edge comprises a pattern of one or more fingers that mates with the pattern of one or more slots of the blade body for removably mating with the first set of slots along the first edge near the first end portion of the blade body.

4. The rotatable blade of Claim 3, wherein the pattern of one or more slots and the pattern of one or more fingers form complementary angles that are not perpendicular to the first long edge of the blade body.

5. The rotatable blade of any one of Claims 2-4, wherein the first cutting edge includes at least one cutout portion for accepting a pry tool and/or for removing accumulated cut vegetation and/or obstructive debris.

6. The rotatable blade of any one of Claims 1 -5 further comprising a retainer bracket for removably securing the first cutting edge to the blade body.

7. The rotatable blade of any one of Claims 1 -6 further comprising a retainer pin for removably securing the first cutting edge to the retainer bracket.

8. The rotatable blade of any one of Claims 1 -7 further comprising a removable aerodynamic wing portion near the first end portion of the blade body.

9. The rotatable blade of any one of Claim 8, wherein the removable aerodynamic wing portion and the retainer bracket are a single unitary piece.

10. The rotatable blade of any one of Claims 1 -9, wherein the first cutting edge provides a cut line that is below a bottom edge of the retainer bracket.

1 1 . The rotatable blade of Claim 6, wherein the retainer bracket comprises a unitary piece of material that, when installed, contacts a top surface of the blade body, a top surface of the first cutting edge, a bottom surface of the blade body, and a bottom surface of the first cutting edge.

12. The rotatable blade of Claim 1 1 , wherein the blade body further comprises a notch on an outer edge for receiving a portion of the retainer bracket such that no significant portion of the retainer bracket extends beyond an outer edge of the replaceable cutting edge and/or beyond an outer edge of the blade body.

13. The rotatable blade of any one of Claims 1 -12, wherein the first cutting edge has a maximum thickness that is equal to or greater than a combined thickness of the blade body and the retainer bracket.

14. The rotatable blade of any one of Claims 1 -13, wherein the retainer bracket includes at least one cutout portion for enabling insertion of a pry tool between the first cutting edge and the blade body.

15. The rotatable blade of any one of Claims 1 -14 further comprising a second replaceable cutting edge removably associated with the second long edge and the second end portion.

16. The rotatable blade of Claim 15, wherein the blade body further comprises a second pattern of one or more slots along the second long edge near the second end portion for removably receiving the second cutting edge, and wherein the second cutting edge comprises a second pattern of one or more fingers for removably mating with the second pattern of one or more slots along the second edge near the second end portion of the blade body.

17. The rotatable blade of Claim 15 or Claim 16, wherein the second cutting edge cutting edge includes at least one cutout portion for accepting a pry tool for removing accumulated cut vegetation and/or obstructive debris.

18. The rotatable blade of any one of Claims 15-17 further comprising a second retainer bracket for removably securing the second cutting edge to the blade body; and a second retainer pin for removably securing the second cutting edge to the second retainer bracket.

19. The rotatable blade of Claim 18, wherein the second cutting edge has a maximum thickness that is equal to or greater than a combined thickness of the blade body and the second retainer bracket.

20. The rotatable blade of Claim 18 or Claim 19, wherein the second retainer bracket includes at least one cutout portion for enabling insertion of a pry tool between the second cutting edge and the blade body.

21 . The rotatable blade of any one of Claims 15=20 further comprising a second removable aerodynamic wing near the second end portion of the blade body.

22. The rotatable blade of Claim 21 , wherein the second removable aerodynamic wing portion and the second retainer bracket are a single unitary piece.

23. A method of improving performance of a rotatable cutting blade according to any one of Claims 1 -22, the method comprising: unmating one or more replaceable cutting edges from the blade body; and mating new or resharpened replaceable cutting edges to the blade body.

24. The method of Claim 21 , wherein the method does not include separating the blade body from an associated mounting apparatus.

25. The method of Claim 23 or Claim 24, wherein the method does not include removing the retaining bracket or the second retaining bracket from the blade body.

26. The method of any one of Claims 23-25, wherein the step of unmating one or more replaceable cutting edges comprises removing a retaining pin from the retaining bracket and the one or more replaceable cutting edges.