The present invention relates to shredder blades. More particularly to a blade set comprised of two blades, forming a grooved incisor blade set.
Paper shredding machines perform a valuable function in destroying documents that otherwise might be misused. Even though there are many varieties and special functions of these machines, they typically all rely upon cutting blades to shred the documents.
The cutting blades must be sturdy enough to withstand the rigor of shredding a great deal of paper. Also, the blades must be economical to produce and easy to incorporate into the paper shredders to enable a low cost of manufacturing.
In many shredders, the assembled cutter structure can be a combination of single blades and blade sets where the blade sets are made of usually two blades affixed together. This arrangement has proven quite successful and efficient in the shredder industry.
There are a number of ways to affix two blades together to arrive at a blade set. These processes could include forms of welding that permanently affix the blades together, or mechanical attachments between the blades where the blades could be remove from one another rather easily.
It is desirable to have the blades more permanently affixed, but processes like welding can be costly and time consuming. What is needed is a way to affix two blades together in a relatively permanent fashion that is less costly and less time consuming than current methods.
Conventional cutting blades tend to become less efficient, as the space between the blades in a set decreases, and become jammed with shredded paper particles. This forces the shredder to work harder to oppose the growing jam, which may occur even below the sheet feed limit of the shredder. Moreover, the jammed paper particles have a tendency to spread apart blade sets, causing blade warping, effortful shredding and, eventually, blade failure. What is needed is a way to relieve the accumulation of shredded paper particles so that shredder effort is reduced and the likelihood of a shredder blade set failure is minimized.
A shredder blade is disclosed, having a crown portion of a blade, a groove portion of the blade juxtaposed with the crown portion, and a center hole adapted to receive a cutting arbor. The hole is disposed through the blade perpendicularly to the crown portion and the groove portion. The crown portion and the groove portion are formed from a strip of metal and define a relief channel The groove portion can be one of a rectilinear shape, a stair-step shape, a curvilinear shape, or an arcuate shape.
Forming may be by stamping, punching, or forging. The crown portion can have a beveled edge. Cutting points, and a dam, also are included with embodiments of the incisor. The crown portion of a blade is formed with a predetermined height, and a predetermined beam.
Also provided is a blade assembly, having a first crown portion of a first blade, a first groove portion of the first blade juxtaposed with the first crown portion, a second groove portion of a second blade in apposition to the first groove portion of the first blade, and a second crown portion of the second blade juxtaposed with the second groove portion of the second blade. The first blade is affixed to the second blade. The assembly can be stepped shape, a V-shape, or a U-shape, or other suitable shapes.
In some embodiments, a cutting point is provided on each of the first crown portion and the second crown portion. In addition, a dam can be advanced from the cutting point. Methods for forming and assembling shredder cutting blades are included. A embodiment of a method for forming shredder cutting blades includes providing a strip of metal, forming an crown in the strip of metal, forming a relief groove juxtaposed to the crown in the strip of metal, and trimming the grooved crown blade of excess metal. Forming the relief groove forms a relief channel. In an embodiment, straightening a rolled strip of metal is performed before providing a strip of metal. The method may include heat-treating the grooved incisor blade.
In some embodiments, forming the crown is by stamping. Forming the relief groove is by the stamping the relief groove juxtaposed to the crown in one of a rectilinear or a curvilinear shape. In selected embodiments, the cutting crown means and the relief groove means are formed from a single piece of metal. A dam means is transverse to the cutting crown means and the relief groove means. In addition, cutting point means are disposed generally transverse to the cutting crown means and to the relief groove means with the dam means being disposed advanced of the cutting point means. In certain embodiments, the shredder blades are formed into an assembly by affixing first and second grooved incisor blades into an assembly, using notched blade locking.
In yet other embodiments, a paper shredder blade set is provided, including a first crown portion of a first blade, a first groove portion of the first blade juxtaposed with the first crown portion and having a notch, forming a notched grooved incisor blade. The notched grooved incisor blade has a substantially round and generally flat shaped body, first and second opposing substantially flat sides, a center hole adapted to receive a cutting arbor, at least two crowns disposed on a periphery of the set body, and at least two notches with each notch extending from a point in the body to the center hole and through the substantially flat sides. The set also includes a second groove portion of a second blade in apposition to the first groove portion of the first blade, and a second crown portion of the second blade juxtaposed with the second groove portion of the second blade, forming a mating grooved incisor blade set, or assembly. The mating grooved incisor blade has a substantially round and generally flat shaped body, first and second opposing substantially flat sides, a center hole adapted to receive a cutting arbor, and at least two cutting points disposed on a periphery of the body. The first substantially flat side of the notched grooved incisor blade contacts the first substantially flat side of the mating grooved incisor blade such that each of the cutting points on the notched grooved incisor blade substantially align with a corresponding cutting point on the mating grooved incisor blade and a groove is formed therebetween.
If present, a dam on the first blade is aligned with a dam on the second blade. Also, an amount of the material from the body of the mating grooved incisor blade is disposed within the notch of the notched grooved incisor blade such that a portion of the amount of material in the notch remains attached to the mating grooved incisor blade, and the notched grooved incisor blade and the mating grooved incisor blade are substantially secured to one another.
In still another embodiment, a method of manufacturing a paper shredder blade set using a notched grooved incisor blade having a substantially round and generally flat shaped body, a first and second opposing substantially flat sides, a center hole adapted to receive a cutting arbor, at least two cutting points disposed on a periphery of the body, and at least two notches with each notch extending from a point in the body through the center hole and through the substantially flat sides, and a mating grooved incisor blade having a substantially round and generally flat shaped body, a first and second opposing substantially flat sides, the center hole adapted to receive a cutting arbor, and at least two cutting points disposed on a periphery of the body, is provided, including placing the first substantially flat side of the notched grooved incisor blade in contact with the first substantially flat side of the mating grooved incisor blade such that each crown on the notched grooved incisor blade substantially aligns with a corresponding crown on the mating grooved incisor blade; and applying force to the second side of the mating grooved incisor blade in a location generally opposite the notch in the notched grooved incisor blade such that an amount of the material from the body of the mating grooved incisor blade is disposed within the notch of the notched grooved incisor blade such that a portion of the material in the notch remains attached to the mating grooved incisor blade, the notched grooved incisor blade and the mating grooved incisor blade are substantially secured to one another, and a groove having a relief channel is formed between the notched grooved incisor blade and the mating grooved incisor blade.
The invention is generally shown by way of reference to the accompanying drawings in which:
In an embodiment of the invention, a blade set is formed from two blades—a notched blade and a mating blade—combined together.
Each blade is approximately disc shaped, but the shape can vary as long as the shape is functional within a paper shredder. Each blade has a body (24) and an opening or hole (26) in approximately the center of the body to accommodate a cutting arbor.
Turning to
Addressing
In
Addressing
The material in the notch (52) can be described as a press or friction fit such that the notch blade (20) and mating blade (30) are held together. The tightness can be regulated as desired in a particular application. Thermal expansion or contraction can also be employed in other embodiments to vary the allowance.
In another embodiment, the notch could be formed by removing material from the body of the notched blade to the periphery. Forcing the material from the mating blade into the notch would proceed in generally the same fashion as identified above.
In another embodiment, holes could be formed through the opposing sides of one blade instead of using notches. Again, the material from the mating blade could be forced into the hole in generally the same fashion as identified above.
In yet another embodiment, combinations of holes and/or notches could be used to join the blades into a blade set.
As used herein, the term “notched blade locking” denotes the notched blade-and-mating blade affixing techniques described above, particularly with respect to
Grooved incisor shredder blades, formed with a relief channel, can provide advantages over common shredder blades, such as blade set 10 in
The pressing of a crown can make the crown denser, and more resistant to damage from paper clips, staples, and minor detritus, although other techniques may be used. Crown height may vary with the form of the groove. A narrower crown beam can allow for increased efficiency but may face an increased likelihood of crown damage during use, limiting the product lifespan. A relief groove can be formed by one or more steps juxtaposed with a crown, providing a generally V-shaped profile (
Useful shredder blade metals include, without limitation, steels such as cold rolled carbon steel (SPCC), or manganese steel, with a Rockwell hardness (HRB) of between about 68 HRB to about 95 HRB. When lower HRBs are used (about 68), the blades may require a form of heat treatment. However, narrower crowns tend to warp with heat treatment, and narrow, softer incisors may be less useful for high-performance products.
Although crowns 810, 910, and 1010, are shown as having flat-cut edges, a crown also can have a bevel or a protruding edge on one or both sides of the crown beam. A beveled edge may provide additional cutting force because of an increased relief channel area for shreddant removal.
A pictorial of a method embodiment for forming a blade of
A general method embodiment for forming grooved incisor shredder blades (S1600) can be explained with the assistance of
The method further may include heat-treating a grooved incisor blade (S1650), where the blade is made of SPCC steel or manganese steel. Due to spreading forces encountered from shreddant, it may be desirable to hold firmly together the blades in an assembly of two or more blades. Affixing the blades (S1660) using the notched blade locking techniques described with respect to
While embodiments have been described in detail, it should be appreciated that various modifications and/or variations may be made without departing from the scope or spirit of the invention. In this regard it is important to note that practicing the invention is not limited to the applications described herein above. Many other applications and/or alterations may be utilized provided that such other applications and/or alterations do not depart from the intended purpose of the invention. Also, features illustrated or described as part of one embodiment may be used in another embodiment to provide yet another embodiment such that the features are not limited to the embodiments described herein above. Thus, it is intended that the invention cover all such embodiments and variations. Nothing in this disclosure is intended to limit the scope of the invention in any way.
Number | Date | Country | Kind |
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201110327535.6 | Oct 2011 | CN | national |
Number | Date | Country | |
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Parent | 13506423 | Apr 2012 | US |
Child | 13480392 | US |