1. Field
The present invention relates generally to blade sharpening devices. More specifically, embodiments of the present invention concern a blade sharpening machine that accommodates various sizes of endless rotary blades.
2. Discussion of Prior Art
Powered rotary knives that have a rotating annular blade are used in the meat processing industry for dressing an animal carcass. The process of dressing the carcass normally involves the removal of meat and fat from bones as well as removal of fat from meat. Rotary knives enable workers to perform this process with much greater efficiency than with traditional, unpowered knives because the annular blade is spun at very high rotational speeds. Blades dull during use and must be sharpened periodically. Powered blade sharpeners for sharpening annular blades are also known in the art. Powered blade sharpeners are used to sharpen annular blades during the blade manufacturing process and to sharpen used blades that have a dull edge.
However, prior art rotary blade sharpeners are problematic and suffer from certain limitations. For example, prior art sharpeners require multiple blade holders for accommodating a range of blade sizes. Blade holders in the prior art are also problematic in that installation and removal of blades is slow and inefficient.
Furthermore, prior art holders also tend to promote uneven sharpening along the blade edge. For example, prior art holders permit the blade to be installed in a position offset from the rotational axis of the sharpener. In addition, prior art holders often deform or warp the held blade. Off-axis positioning and blade deformation result in uneven sharpening of the blade edge, which can further reduce the life of the blade and increase the cost of providing blades for a rotary knife. These problems are further aggravated by the severity of blade wear that is common in the industry. In order to avoid production down-time, processors must keep a large supply of blades on hand as well as invest significant capital in purchasing and maintaining numerous blade holders and powered sharpeners.
Accordingly, there is a need for an improved rotary blade sharpener that does not suffer from these problems and limitations.
Embodiments of the present invention provide a universal blade sharpener that does not suffer from the problems and limitations of the prior art sharpeners set forth above.
A first aspect of the present invention concerns a universal blade holder operable to be rotatably driven by a blade-sharpening drive having an adjustable blade sharpener. The universal blade holder is configured to securely hold any one of multiple variously sized circular blades while being sharpened by the adjustable blade sharpener, wherein each of the circular blades includes drive teeth disposed in an annular arrangement. The universal blade holder broadly includes a blade-receiving chassis operable to be rotated by the drive and rotatable about a rotation axis of the blade holder. The blade-receiving chassis includes a plurality of radially spaced blade-retaining sections each associated with a respective one of the circular blades. Each blade-retaining section includes at least a partial ring of positioning teeth projecting from the chassis and is configured to intermesh with the drive teeth of the respective one of the circular blades, thereby restricting rotational and off-axis movement of the respective one of the circular blades relative to the chassis.
A second aspect of the present invention concerns a universal blade sharpening machine operable to securely hold and sharpen any one of multiple variously sized circular blades, wherein each of the circular blades includes drive teeth disposed in an annular arrangement. The universal blade-sharpening machine broadly includes a blade-sharpening drive and a universal blade holder. The blade-sharpening drive has an adjustable blade sharpener. The universal blade holder is rotatably powered by the drive and is configured to securely hold the blade that is held during sharpening by the adjustable blade sharpener. The universal blade holder includes a blade-receiving chassis drivingly connected to the drive and rotatable about a rotation axis of the blade holder. The blade-receiving chassis includes a plurality of radially spaced blade-retaining sections each associated with a respective one of the circular blades. Each blade-retaining section includes at least a partial ring of positioning teeth projecting from the chassis and is configured to intermesh with the drive teeth of the respective one of the circular blades, thereby restricting rotational and off-axis movement of the respective one of the circular blades relative to the chassis.
A third aspect of the present invention concerns a universal blade holder operable to be rotatably driven by a blade-sharpening drive having an adjustable blade sharpener. The universal blade holder is configured to securely hold any one of multiple variously sized circular blades while being sharpened by the adjustable blade sharpener. The universal blade holder broadly includes a blade-receiving chassis and a plurality of magnets. The blade-receiving chassis is operable to be rotated by the drive and is rotatable about a rotation axis of the blade holder. The blade-receiving chassis includes a plurality of radially spaced blade-retaining sections each associated with a respective one of the circular blades. Each blade-retaining section includes a locating element that projects from the chassis and is configured to engage a complemental feature of the blade to restrict rotational movement of the blade relative to the chassis about the rotation axis. The plurality of magnets are supported on the blade-receiving chassis, with each blade-retaining section associated with a corresponding magnet that is configured to cooperate with the locating element to secure the respective one of the circular blades in driving engagement with the blade-receiving chassis.
Other aspects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments and the accompanying drawing figures.
Preferred embodiments of the invention are described in detail below with reference to the attached drawing figures, wherein:
The drawing figures do not limit the present invention to the specific embodiments disclosed and described herein. The drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the preferred embodiment.
Turning initially to
The drive unit 22 includes, among other things, a substantially rigid base 26 and a rotatable platform 28 that supports the blade holder 24 (see
The drive unit 22 further includes a sharpening assembly 32 mounted on the base 26 adjacent to the platform 28. The sharpening assembly 32 is operable to sharpen the blades B1,B2 and includes an adjustable stanchion 34 attached to the base 26. The stanchion 34 includes an adjustable post 36 and an arm 38 rotatably mounted on the post 36 and pivotal about an upright axis presented by the post 36. A bracket 40 is attached to an uppermost end of the post 36 and presents a distal slot 42 with a plurality of discrete slot segments 44 (see
The sharpening assembly 32 is operable to selectively position the grinding wheel 52 relative to the blade secured on the blade holder 24. Specifically, the sharpening assembly 32 is shiftable to adjust the height of the grinding wheel 52 relative to the platform 28 (measured along a rotational axis A of the blade holder 24). Also, the arm 38 pivots relative to the post 36 to shift the grinding wheel 52 about the axis of post 36 between a blade-attachment position (see
Turning to
Turning to
The inboard face 66 presents radially-spaced groups of seats 76a,b,c,d that are sized and configured to receive magnets 60. Each of the seats 76 comprises a circular socket defined by a shoulder, with the seats 76 preferably at least partly receiving a corresponding magnet 60. However, it is also within the ambit of the present invention where the seats 76 are alternatively shaped (e.g., the seats 76 could be configured to entirely receive corresponding magnets). Additionally, for some aspects of the present invention, the backing plate 64 may be devoid of seats 76, e.g., where only the locating plate 62 serves to position the magnets 60 relative to the axis A. As will be discussed in greater detail, the seats 76 are located to position the magnets 60 in predetermined locations on the chassis 58.
The backing plate 64 also includes a pair of countersunk holes 78 that receive flathead fasteners 80 for attaching the backing plate 64 to the platform 28. The backing plate 64 further includes threaded holes 82 that receive flathead fasteners 84 for attaching the plates 62,64 to each other.
The illustrated locating plate 62 is configured to receive blades B1,B2 and preferably comprises a unitary and circular construction. The locating plate 62 presents opposite inboard and outboard faces 86,88, and an endless outer edge 90. However, it is within the scope of the present invention where the locating plate 62 presents an alternative shape that permits the chassis 58 to support various blades. Similar to the backing plate 64, the locating plate 62 could also be comprised of multiple portions attached to one another.
The inboard face 86 includes a socket 92 defined by an outer shoulder 94 that extends along the outer edge 90 (see
Turning to
The endless rings of teeth are preferably substantially centered about the rotation axis A of the blade holder 24. Furthermore, the teeth 100 of each section 98a-e present a corresponding arcuate locating surface 102a-e that centers the endless blades relative to the rotation axis A. In this manner, the blade holder 24 promotes uniform sharpening of the endless blades. Locating surfaces 102a-d are preferably endless, but it is also within the scope of the present invention where the locating surfaces 102a-d are not endless (such as locating surface 102e, which is interrupted by a pair of bores). Furthermore, the locating surfaces 102 could each include a feature other than teeth 100 for centering the endless blades, e.g., a circumferentially-extending shoulder that engages an inner or outer edge of teeth 100. The locating plate 62 preferably includes five sections 98a-e that are sized to correspond to standard blade sizes with blade diameters ranging from about one and one-quarter (1.25) inches to about five (5) inches, but more or fewer sections 98 could be included on the locating plate 62 without departing from the scope of the present invention. More preferably, the locating sections 98 present the following outermost diameter dimensions:
In the illustrated embodiment, the locating plate 62 is depicted as receiving blades B1,B2. Blade B1 includes a blade wall 104 and ring gear 106, with the blade wall 104 including a support section 108 and cutting section 110. The support section 108 interconnects the ring gear 106 and cutting section 110 (see
While the illustrated blade-sharpening machine 20 is preferably configured for sharpening the blade B1, various other blade shapes can be accommodated, such as alternative endless blade B2 (see
Turning to
In addition, the seats 96 in each group are preferably spaced uniformly from each other in a circumferential direction. More preferably, six (6) seats 96a are spaced at an angle of sixty (60) degrees from adjacent seats 96a, four (4) seats 96b are spaced at an angle of ninety (90) degrees from adjacent seats 96b, four (4) seats 96c are spaced at an angle of ninety (90) degrees from adjacent seats 96c, and two (2) seats 96d are spaced at an angle of one hundred eighty (180) degrees from adjacent seats 96d. However, the seats 96 could have an alternative circumferential spacing without departing from the scope of the present invention.
Preferably, seats 76 are positioned on plate 64 so as to be aligned with corresponding seats 96 when the plates 62,64 are attached to one another (see
The magnets 60 each preferably include a rare earth permanent magnet material. More preferably, the magnets 60 include a neodymium alloy material. However, it is also within the ambit of the present invention where the magnets 60 include other materials. Furthermore, the magnets 60 could comprise an electromagnet without departing from the scope of the present invention. The magnets 60 also preferably present a cylindrical form with a diameter between about one-quarter (0.25) inch and about one (1) inch and a thickness between about one-eighth (0.125) inch and about one-half (0.5) inch. This arrangement keeps the vertical profile of the chassis small, while providing a secure means for releasably holding each blade on the corresponding locating section 98. However, the magnets 60 could present an alternative size and/or shape without departing from the scope of the present invention.
Turning again to
Annular blades B1,B2 are selectively secured to the blade holder 24 by intermeshing the gear teeth of the blade with teeth 100 of the corresponding locating section 98. As discussed previously, the locating section 98 intermeshes with the teeth of the blade to restrict relative rotational movement between the blade and blade holder 24. Furthermore, the locating section 98 restricts off-axis lateral movement of the blade relative to the blade holder 24 (i.e., the locating section 98 centers the blade on the blade holder 24). Yet further, the blades B1,B2 preferably include a ferrous material that is attracted to the magnets 60, and the magnets 60 thereby hold the blade against the locating plate 62 by applying a magnetic force to the blade. Thus, the magnets 60 restrict blade movement along the rotation axis A. The magnets consequently serve as a securing system for releasably securing each blade against the chassis 58. However, according to certain aspects of the present invention, the blade holder may be provided with an alternative securing system or no securing system at all. For example, the holder could alternatively (or in addition to the magnets 60) be provided with an adhesive (such as a removable hot glue) for holding the blade against the respective locating section.
In operation, the motor 50 and grinding wheel 52 of the sharpening assembly 32 are pivoted out of the blade-sharpening position and into the blade-attachment position to permit installation of the blade B1, blade B2, or another annular blade onto the machine 20. The blade B1 is secured in the blade holder 24 by positioning teeth 112 of the blade B1 into intermeshing engagement with teeth 100 of locating section 98a (see
The blade B1 is removed from the machine 20 by initially pivoting the sharpening assembly 32 out of the blade-sharpening position. The blade B1 is removable from the blade holder 24 by pulling the blade B1 away from the chassis 58, i.e., by overcoming the magnetic force applied to the blade B1 by the magnets 60.
The preferred forms of the invention described above are to be used as illustration only, and should not be utilized in a limiting sense in interpreting the scope of the present invention. Obvious modifications to the exemplary embodiments, as hereinabove set forth, could be readily made by those skilled in the art without departing from the spirit of the present invention.
The inventor hereby states his intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of the present invention as pertains to any apparatus not materially departing from but outside the literal scope of the invention as set forth in the following claims.
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Number | Date | Country | |
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20100323591 A1 | Dec 2010 | US |