Patent Application
20150336103
This disclosure relates to a shredder blade assembly that includes interchangeable knife inserts with six cutting edges.
Industrial shredding machines are used to shred or reduce objects into smaller pieces for reuse or recycle. Shredding machines are commonly rotary shredders comprising pairs of counter-rotating, intermeshing, serrating and shearing blade assemblies or cutting wheels. The blade assemblies are mounted on parallel rotating shafts. The number of pairs of parallel blade assemblies on a single shaft can vary. A larger number of blade assemblies will increase the capacity of the shredder. The parallel blade assemblies are separated by spacers to allow intermeshing of another set of parallel blade assemblies on another shaft.
In the shredding zone, the tire or article to be shredded encounters the outer periphery of the counter-rotating blade assemblies. After continuous shredding for a period of time, the outer periphery of the blade assembly becomes worn by the toughness of tires or articles being shredded. These cutting or shearing surfaces would need to be resurfaced. The problem of resurfacing cutting wheels has been addressed by using a modular construction of blade assemblies comprising a rotor structure upon which a plurality of cutting and shearing surfaces are attached. The outer peripheral contact region of a blade assembly is removed and replaced instead of removing the entire wheel from its shaft for repair. This is done by removing individual cutting and shearing surfaces, or knives, from the rotor.
It will be appreciated that there is a need in the art for shredder blade assemblies that can be quickly and efficiently maintained to reduce equipment down-time and expensive repair on industrial shredders.
It will further be appreciated that there is a need in the art for shredder blade assemblies with replaceable knife inserts that have a long usable lifespan, thereby lowering maintenance costs.
A shredder blade assembly is disclosed that includes a rotor upon which are mounted interchangeable knife inserts.
Each knife insert has six cutting or shearing edges. It may have a triangular or modified-triangular shape. During shredder operation, only one of the six cutting edges is subject to wear. After one cutting edge is worn, the knife insert is rotated 120°, thereby exposing another edge. The knife insert may be rotated to expose the three cutting edges on one side of the knife insert. After all three cutting edges on one side are worn, the entire knife insert is flipped over and rotated as needed to expose three additional cutting edges. The knife inserts are held in place by a symmetrical hole pattern that enables correct placement and bolting of the knife insert onto the rotor despite being rotated and flipped.
The knife inserts are preferably fabricated of a high alloy steel and/or tool steel. The knife inserts may optionally be coated with wear resistant surface coatings. The knife inserts may optionally be fabricated with carbide wear edges.
When the knife insert is inserted onto the rotor its triangle shape and the way it is inserted onto the rotor creates a positive angle tooth/hook, much like a saw tooth, that pulls material through the opposing cutting edges more efficiently than other insert types.
In one non-limiting embodiment, the knife inserts are staggered on each side of the rotor so that the teeth/hooks are offset to create a smoother flow of material into the blade assembly as they cut, shear, and shred the material. Without being bound by theory, it is believed that the smoother flow of material into the blade assembly produces less stress and wear on the gears and motors that drive the shredder.
In order that the manner in which the above-recited and other features and advantages of the invention are obtained will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof that are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:
The present embodiments of the present invention will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. It will be readily understood that the components of the present invention, as generally described and illustrated in the figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the shredder blade assembly, is not intended to limit the scope of the invention, as claimed, but is merely representative of present embodiments of the invention.
The disclosed invention relates to a shredder blade assembly having interchangeable knife inserts. One non-limiting embodiment of a shredder blade assembly 100 is shown in
The knife inserts 120 are mounted to the rotor using suitable fasteners 130. The fasteners 130 may be screws, such as socket head cap screws. As shown, each rotor may be mounted using screws in a symmetrical screw hole pattern. A symmetrical hole pattern enables correct placement and bolting of the knife insert 120 onto the rotor 110 despite being rotated and flipped. In one disclosed embodiment, three fasteners 130 are used to mount each knife insert 120. In another embodiment, a single centrally located fastener may be used to mount each knife insert 120. It is understood that precise number of holes and fasteners used may vary.
The disclosed knife inserts 120 are preferably made in the shape of an equilateral triangle. They are mounted in a way to expose one vertex of the triangle to create a positive angle tooth/hook 140, 142 much like a saw tooth, that pulls material through the opposing cutting edges more efficiently than other shredder blade insert types. It will be understood that the shape of the knife inserts may be modified to another polygonal shape and still provide six cutting and shearing edges. For instance, the knife insert may have a modified triangular shape, such as a hexagonal shape. As used herein, a modified triangular shape includes a shape that still has three dominant sides or edges, but may not be “technically” a triangle. A modified triangular shape that is hexagonal may be achieved by removing a portion of each vertex of the equilateral triangle. The precise angle and amount removed from each vertex may vary.
In one non-limiting embodiment, the knife inserts are staggered on the each side of the rotor so that the teeth/hooks 140, 142 are offset to create a smoother flow of material into the shredder blade assemblies as they cut, shear, and shred the material. Without being bound by theory, it is believed that the smoother flow of material into the blade assembly produces less stress and wear on the gears and motors that drive the shredder.
Rotary shredders comprise pairs of counter-rotating, intermeshing, serrating and shearing blade assemblies.
Each shaft rotates in an opposite direction, as shown by arrows 150, 152 so that the article to be shredded is drawn into a shredding zone indicated by arrow 154. Within the shredding zone 154, the exposed outer edge of knife inserts on one blade assembly 100 (identified as “A” in
The parallel blade assemblies are separated by spacers 160 to allow proper spacing and intermeshing of an opposing set of parallel blade assemblies on another shaft. The width or thickness of the spacers may vary as needed to ensure that opposing blade assemblies interact to produce the cutting, shearing, or shredding function. A representative example of a blade assembly spacer is shown in
Each knife receptacle includes one or more holes 172 disposed in a symmetrical hole pattern to receive suitable fasteners used to mount a knife insert. As described above, the symmetrical hole pattern enables correct placement and bolting of knife insert onto the rotor 110 despite being rotated and flipped.
The ability to use a knife insert with six cutting or shearing edges greatly extends the useful life of the knife insert. This can reduce operating and maintenance costs for the shredder.
The knife inserts 120 are mounted to the rotor by fasteners 130 using holes 180 arranged in a symmetrical hole pattern that enables correct placement and bolting of the knife insert 120 onto the rotor 110 despite being rotated and flipped, as described above.
The knife inserts are preferably fabricated of a high alloy steel and/or hardened tool steel. The knife inserts may optionally be coated with wear resistant surface coatings. In a non-limiting embodiment, the knife inserts are fabricated with carbide wear edges.
While specific embodiments and examples of the present invention have been illustrated and described, numerous modifications come to mind without significantly departing from the spirit of the invention, and the scope of protection is only limited by the scope of the accompanying claims.
