Two-stage shredder system and related methods of shredding

Abstract

Shredder systems can include a primary shredder and a secondary shredder. The primary shredder is configured to shred sheet type materials, such as paper into a first shredded product. The secondary shredder is configured to further shred the first shredded product to produce a second shredded product. In examples, the shredder system can include an overflow 5 chamber between the primary shredder and the secondary shredder.

Description

TWO-STAGE SHREDDER SYSTEM AND RELATED METHODS OF SHREDDINGFIELD OF THE INVENTION

[0001] This disclosure relates to waste shredder systems, such as for bulk paper.BACKGROUND OF THE INVENTION

[0002] Paper shredders often include one or more rotating shafts with knives. Some shredder arrangements can include a single shaft, whereas other shredder arrangements can include multiple shafts (e.g., two shafts, four shafts, etc.). In addition, some shredders can be multistage shredders, which can include a first shredder positioned in a first stage (e.g., a two-rotor shredder) and a second shredder positioned in a second stage (e.g., a single shaft shredder). In some instances, multi-stage shredders can operate to process materials (e.g., paper) into smaller pieces, which can sometimes increase security and confidentiality associated with the shredded material.BRIEF DESCRIPTION OF THE DRAWINGS

[0003] Illustrative embodiments of the present invention are described in detail below with reference to the attached drawing figures, which are incorporated by reference herein and wherein:

[0004] FIG. 1 is an illustration showing a cross-sectional view through a prior art shredder system having a primary shredder and a secondary shredder;

[0005] FIG. 2A is an illustration showing a cross-sectional view through a first example shredder system, in accordance with aspects of the present disclosure;

[0006] FIG. 2B is an illustration showing a perspective view of the shredder system shown in FIG. 2A, in accordance with aspects of the present disclosure;

[0007] FIG 3A is an illustration showing a cross-sectional enlarged view of the shredder system shown in FIG. 2A, when in a first state, in accordance with aspects of the present disclosure;

[0008] FIG. 3B is an illustration of disc knives of a primary shredder of the shredder system shown in FIG. 2A, in accordance with aspects of the present disclosure;

[0009] FIG. 3 C is an illustration showing a cross-sectional enlarged view of the shredder system shown in FIG. 2A, when in a second state, in accordance with aspects of the present disclosure;

[0010] FIG. 3D is an illustration of disc knives of a secondary shredder of the shredder system shown in FIG. 2A, in accordance with aspects of the present disclosure;

[0011] FIG. 4 is an illustration showing a cross-sectional view through a second example shredder system having a primary shredder, a secondary shredder, a conveyor, and a collection chamber, in accordance with aspects of the present disclosure;

[0012] FIG. 5 is an illustration showing a cross-sectional view through a third example shredder system, in accordance with aspects of the present disclosure;

[0013] FIG. 6 is an illustration showing a cross-sectional view through a fourth example shredder system where a collection chamber acts as a chute to direct a first shredded product from a primary shredder to a secondary shredder, in accordance with aspects of the present disclosure; and

[0014] FIG. 7 is an illustration showing a cross-sectional view through a fifth shredder system including a sorter between a primary shredder and a secondary shredder, in accordance with certain aspects of the present disclosure.DETAILED DESCRIPTION OF THE INVENTION

[0015] The present disclosure is directed to a shredder with improved shredding capabilities, such as the ability to consistently shred material (e.g., paper) to at least a desired minimum size or smaller, to reduce the likelihood of backup, and to reduce the likelihood of knife clogging. In at least some examples, the shredder can include a two-stage shredder, which can include a first shredder assembly (e.g., two rotor shredder) and a second shredder assembly (e.g., single rotor shredder). However, in at least some instances, the subject matter of this present disclosure could also be implemented in a single stage shredder (e.g., a dual-shaft shredder, a single-shaft shredder, a quad-shaft shredder, etc.).

[0016] In examples, a shredder of the present disclosure can include an expansion chamber (e.g., surge chamber or overflow chamber) that is positioned near the bite of a shredder and that provides an expansion plenum or volume into which material can accumulate while awaiting feeding into the bite. That is, the expansion chamber can be positioned along the material feeding path leading to the bite. In examples, the ability of the material to accumulate in the expansion chamber can reduce the likelihood of backup further upstream (e.g., from where the material is being fed).

[0017] For example, in instances in which the expansion chamber is incorporated in a multistage shredder having an upstream shredder assembly and a downstream shredder assembly, the expansion chamber can be positioned near the bite the downstream shredder assembly to reduce the likelihood of material building up and accumulating between the upstream shredder assembly and the downstream shredder assembly. That is, in examples, a secondary shredder is constantly (or semi-constantly or intermittently) fed with the first shredded product collected in the collection chamber. When output from the primary shredder exceeds a handling capacity of the secondary shredder, the first shredded product may further collect in an overflow chamber that is fluidly connected to the collection chamber. The overflow chamber allows thesecondary shredder to catch up and output a second shredded product having a second shred size that meets a second desired security standard. In other words, due to the varied cutting operations as between the primary and secondary shredder (e.g., more detailed cutting required by the secondary shredder), the shredding speed of the primary shredder and the secondary shredder may be different. For example, outputting the second shredded product may be more time consuming than outputting the primary shredded product. Thus, the overflow chamber helps in preventing clogs that may happen in the system if the secondary shredder becomes overwhelmed.

[0018] In some examples, the expansion chamber can be positioned near the bite of a shredder assembly in a single-stage shredder, such as to provide a relief plenum for material being fed through a hopper or other material feeding structure (e.g., where the material is being fed at a rate faster than the throughput of the shredder).

[0019] In at least some examples, the present disclosure can include a compressed air blower (e.g., air knife) that is positioned to direct air to one or more various portions of the shredder. For example, the blower can blast compressed air against knives of the shredder in order to dislodge material from the knife pockets or other recesses associated with the knives (e.g., hub pockets) or associated with the shredder. In some examples, the blower can be directed across the material feeding path or other plenum upstream of the shredder blades to direct the material towards the bite. In some instances, the blower can direct material into (or towards) the expansion chamber. In some examples, the shredder can include a bypass chute that allows material to flow past a shredder assembly without being shredded and that can be blocked with a door or flap. The blower can, in such instances, be directed towards the flap and can reduce the likelihood of material building up on the flap.

[0020] In at least some examples, stationary material aligners (e.g., sometimes referred to as “fingers” or “finger extensions”) can be affixed upstream of the bite of a shredder and can urge material in a desired orientation for feeding into the bite. That is, absent the aligners, sheet material can have a tendency to lay across the top of the knives (e.g., lay more horizontally), which can sometimes contribute to poor shredding (e.g., shredded pieces are too large). In examples of this disclosure, the aligners are positioned directly above the knives and urge or position the sheet material into a more vertical orientation that is generally aligned with the bite, which has been shown to contribute to improved shredding (e.g., into smaller pieces).

[0021] In at least some instances, a shredder system may have a primary shredder that first cuts the paper (or similar material) into relatively long pieces that meet ISO Pl and / or ISO P2 security standards, the resulting first shredded product including strips may have a width of about 12 mm to about 16 mm and a first shred size that is at least 800 mm2. The term “about” as used herein means that the actual value may be within ± 10% of the given value. The shred size provided above is a suitable shred size that can undergo a second shredding operation. In accordance with aspects herein, the first shredded product enters a secondary shredder that performs a second shredding operation. As a result, the final shredded product includes particles that are substantially smaller than the strips included in the first shredded product resulting from the first shredding operation by the primary shredder, and meet ISO P3 and higher security standards. The particles may have a width of about 0.5 mm to about 6 mm and a second shred size that is at most 320 mm2, thereby making reassembly of the final shredded product practically impossible.

[0022] The shredder system in accordance with aspects herein includes a primary shredder that outputs a first shredded product having a first shred size that meets a first desired securitystandard. The shredder system is further equipped with a collection chamber configured to collect the first shredded product from an outlet of the primary shredder.

[0023] Further, because of the higher security standards required for the secondary shredder, the blades of the secondary shredder may be designed differently from the blades of the primary shredder. For example, the blades of the secondary shredder may be equipped with a greater number of cutting edges than the blades of the primary shredder.

[0024] The shredding system in accordance with aspects herein may be dynamic in that it can be utilized to provide shredded product of different sizes because the secondary shredder may be turned on or off. In other words, when the security standards desired are low (ISO Pl or ISO P2), only the primary shredder may be activated, however, when the security standards desired are higher (ISO P3 or above), the secondary shredder may be activated.

[0025] The shredding system in accordance with aspects herein may also be equipped with load sensors in the primary shredder and the secondary shredder to activate different components of the shredding system to relieve load stress from the primary shredder and / or the secondary shredder prior to causing equipment damage or malfunction of the shredding system.

[0026] Various examples are described below with reference to the drawings, and the structure, relationship, and / or functioning of examples can, in some instances, be better understood by reference to this detailed description. However, examples associated with the subject matter of this application are not limited to those illustrated in the drawings or explicitly described below. The drawings might not necessarily be to scale. In some instances, for clarity, brevity, and / or simplicity details might have been omitted, which does not preclude the inclusion of those details in association with examples of this disclosure. Some features that are illustrated may not be discussed, and those features may be inherentfrom the figures themselves. Other non-discussed features may be inherent in component geometry and / or configuration.

[0027] Turning now to the figures, FIG. 1 is an illustration showing a cross-sectional view of a two-stage shredder system 102, which is in the prior art. As shown in FIG. 1, the shredder system 102 may generally include a primary shredder 104, a secondary shredder 106, and an auger 108. The primary shredder 104, depicted with two counter-rotating shredder rotors 116 and associated knives 118, can shred material to a first shred size, and the secondary shredder 106 depicted with only one shredder rotor 120 and associated knives 122, can further shred the material shredded by the primary shredder 104 to a smaller shred size (e.g., the shredded product 114). Afterwards, the auger 108 can be configured to transport the shredded material away from the secondary shredder 106 and to another location (e.g., a waste pile, a storage bin, or the like). Additional details and aspects of two-stage shredders used with success are disclosed in U.S. Patent No. 10,086,380 (Y amamoto et al., “SHREDDING RECYCLABLE MATERIAL CONTAINING INFORMATION”), issued October 2, 2018, and assigned to SHRED-TECH CORPORATION of Ontario, Canada, which is hereby incorporated by reference in its entirety.

[0028] As shown in FIG. 1, when a first shredded product leaves the primary shredder 104, it enters a collection chamber 110 between the primary shredder 104 and the secondary shredder 106. When the primary shredder 104 is operating at a high capacity, it may fill this collection chamber 110 faster than the collection chamber 110 can be cleared by the secondary shredder 106. This may cause the first shredded product 112 to pack together such that a relatively high particle density of the first shredded product 112 exists inside this collection chamber 110. The inventors have found that the performance of the secondary shredder 106 may be impacted when the first shredded product 112 enters the secondary shredder 106 witha high particle density. For example, compacted paper particles at the entrance of the secondary shredder 106 may cause hub hooks (or other components) of the secondary shredder 106 to plug, thereby reducing the throughput capacity of the secondary shredder 106 (which can exacerbate the problem). Additionally or alternatively, this phenomenon may cause the first shredded product 112 to enter the secondary shredder 106 in a folded or otherwise compressed, causing the particles from the primary shredder to flow through the secondary shredder 106 without sufficient cutting, thereby outputting a shredded product that does not meet the security standards desired. In extreme situations, such compaction may force the first shredded product 112 into the secondary shredder 106 at a rate beyond what the secondary shredder 106 can handle (resulting in damage to the shredder system).

[0029] Aspects disclosed herein address these shortcomings of prior shredder systems. For instance, as shown in FIG. 2A, a shredder system 200 includes certain improvements that address the issues discussed above. Specifically, FIG. 2A is an illustration showing a cross- sectional view of the shredder system 200 having a primary shredder 202 and a secondary shredder 204. As shown, the shredder system 200 includes a primary shredder 202 that is fluidly connected to hopper 206 such that as material (e.g., paper, cardboard, film, etc.) is dumped into the hopper 206 for shredding, gravity aids the material to make contact with the primary shredder 202.

[0030] The shredder system 200 further includes a collection chamber 208, where a first shredded product coming out of the primary output 210 of the primary shredder 202, is collected. As shown, the collection chamber 208 is fluidly connected with an overflow chamber 212 where any excess shredded product can collect if necessary. The shredder system 200 can have a first state or active condition where the primary shredder 202 is active, but the secondary shredder 204 may be less active or not active. In this first active condition(as shown in FIG. 2A and FIG. 3A), a movable panel 214 (e.g., pivoting or rotating wall, door, flap, etc.) can be in an open configuration, which allows the shredded product from the primary shredder to at least partially bypass the secondary shredder 204 directly toward the auger 216 as shown in FIG. 3 A. The auger 216 is configured to transport shredded product away from the primary shredder 202 when the product passes through the opening formed by the movable panel 214 in the open configuration, and from the secondary shredder 204 when the secondary shredder is also active.

[0031] In some examples, clogging of the primary shredder 202 may be reduced or rendered less likely by finger extensions 218 (e.g., FIGS. 2A, 2B, and 3C). More specifically, the finger extensions 218 of the primary shredder 202 are configured to prevent a build-up of shredded material between the disc knives 310 of the primary shredder 202. The finger extensions 218 may be positioned along at least a portion of the first rotating shaft 306 and / or along the rotating second shaft 308. That is, the finger extensions can be fixed relative to the first rotating shaft 306 and / or the second rotating shaft 308, such as by being affixed to a wall or other structure of the shredder, and the finger extensions 218 can be arranged along the shafts by interdigitating between the knives attached to the shafts. The bottom portion of each finger of the finger extensions 218 includes an edge that is positioned near the central hub of the set of knives 310. For example, the edge can include a rounded edge that is concave with a curvature that corresponds with a shape of a portion of the central hub. In at least some examples, the rounded edge is crescent shaped. This lower portion of the finger extension 218 is shown in FIG. 2B, in which a first portion 218a of the finger extension 218 extends along a top portion of the set of knives and a second portion 218b of the finger extension 218 extends underneath the set of knives. A crescent shaped body can connect the first portion 218a to the second portion 218b. In examples, the edge and the lower portion of the finger extensions 218 can function to dislodge material from accumulating near the huband / or can push material out of that space. The finger extensions 218 can lift material out from between the disc knives 310 (e.g., from a gap between adjacent knives) of the primary shredder 202 and cause the shredded material to clear the disc knives 310. In addition, the second portion 218b that is below the set of knives can include an edge that faces towards the collection chamber 208 and the secondary shredder 204 and that guides the shredded material toward the secondary shredder 204.

[0032] In at least some examples, a shredder (e.g., the primary shredder and / or the secondary shredder) can include one or more material aligners 219. The aligners 219 can include a portion of the fingers or finger extensions 218 (e.g., an edge, plate, face, etc. of the finger extensions). In at least some examples, the aligners 219 (e.g., sometimes referred to as “fingers” or “finger extensions”) can be affixed upstream of the bite of a shredder and can urge material in a desired orientation for feeding into the bite. That is, absent the aligners 219, sheet material can have a tendency to lay across the top of the knives (e.g., lay more horizontally), which can sometimes contribute to poor shredding (e.g., shredded pieces are too large). In examples of this disclosure, the aligners 219 are positioned directly above the knives and urge or position the sheet material into a more vertical orientation that is generally aligned with the bite, which has been shown to contribute to improved shredding (e.g., into smaller pieces).

[0033] Moving onto FIG. 3A, FIG. 3A is an illustration showing a cross-sectional close-up view 300 of the shredder system 200 when in the first active condition, where the primary shredder 202 active. As shown, in this first active condition, the movable panel 214 is “open” or in other words, it is pivoted away from the secondary shredder 204 so that an open path 302 is created so that the first shredded product 304 that comes out of the primary output 210 of the primary shredder 202 flows directly toward the auger 216 (shown in FIG. 2A). As discussed above, first shredded product 304 output by the primary shredder 202 may be configured tomeet a first security standard that is, for example between ISO Pl and ISO P2. For example, the first shredded product 304 may be shaped as strips of a chosen width based on a chosen shred size. The strips may have a width of about 12 mm to about 16 mm and a first shred size that is at least 800 mm2according to ISO Pl or ISO P2.

[0034] The primary shredder 202 may include two counter rotating shafts 306 and 308, and each of the two counter rotating shafts 306 and 308 may be loaded with a plurality of disc knives 310 as shown in FIG. 3B. Each disc knife 310 mounted on the two counter rotating shafts 306 and 308 having, for example, six disc knife hooks 314. As further shown in FIG. 3B, when a plurality of disc knives 310 are grouped and loaded onto the rotating shaft 306 or 308, as shown in grouping 316, they may be loaded such that the disc knife hooks 314 are staggered rather than aligned with each other. The disc knife hooks 314 are located around a periphery of each disc knife 310.

[0035] In some examples, each disc knife 310 may have a width 312 be about 11.0 mm to about 16.0 mm wide, about 11.2 mm to about 15.9 mm, about 11.4 mm to about 15.88 mm wide, and the like. In some cases, a shred size of the first shredded product 304 may be determined by the width 312 of each disc knife 310. The primary shredder 202 may be driven by a hydraulic manifold system equipped with a pressure sensor (not shown) such as, for example, a hydraulic pressure sensor with a 0-6000 pounds per square inch (psi) input and a 0- 5 volts of direct current (VDC) output. The pressure sensor allows for monitoring a load on the primary shredder 202, particularly when the shredder system 200 is operated in a second active condition (i.e., high security mode), as will be discussed in further detail with respect to the secondary shredder 204.

[0036] FIG. 3C shows a cross-sectional close-up view 320 of the shredder system 200 when in the second active condition. As shown, in the second active condition, the secondaryshredder 204 is activated so that the shredder system 200 is configured to further shred the output from the primary shredder 202. In some examples, this can include a higher security mode to meet a second security standard that is, for example between ISO P3 or higher, such as ISO P4, ISO P5, and ISO P6. When the shredder system 200 is in the second active condition, the movable panel 214 is raised away from a wall 322 of the shredder system 200 to position it to close (i.e., block) the open path 302. In other words, rather than being stowed against the wall 322 (e.g., in a more parallel configuration with the wall 322), as in the first active condition, the movable panel 214 is raised (e.g., by rotating the movable panel on a hinge) so that an angle 324 (e.g., less parallel) is formed between the wall 322 and the movable panel 214. Thus, in the second active condition, when the first shredded product 304 is outputted by the primary shredder 202, rather than falling toward the auger 216, the first shredded product 304 is accumulated in collection chamber 208 as it is further processed by the secondary shredder 204 to create a higher security second shredded product 326. The higher security second shredded product 326 is then moved away from the shredder system 200 by the auger 216.

[0037] The secondary shredder 204, unlike the primary shredder 202, may include at least one rotating shaft 328 loaded with a plurality of disc knives 330, shown in further detail in FIG. 3D. In some examples, a disc knife 330 can include a greater number of knife hooks 332 than the disc knives 310. For example, the disc knife 330 may have eight to thirteen knife hooks 332. Further, each disc knife 330 may further comprise hub hooks 334. The knife hooks 332 are located around the periphery of each disc knife 330. The knife hooks 332 may be arranged to promote crosswise alignment of the strips corresponding to the first shredded product 304, and make it possible to easily grab the strips corresponding to the first shredded product 304 output by the primary shredder 202.

[0038] The hub hooks 334 are cut into each hub 336 of each disc knife 330. The hub hooks 334 may provide a secondary cutting action so that together with the knife hooks 332 create a cutting action along the entire rotating shaft 328. The hub hooks 334 are machined wider than the knife hooks 332 and with a shape to facilitate efficient shred ejection from the secondary shredder 204. The throughput capacity of the secondary shredder 204 may be increased by increasing a number of knife hooks 332 and hub hooks 334 for each disc knife 330 by increasing a number of cuts per rotor revolution. The knife hooks 332 and hub hooks 334 may be located around the periphery of the each disc knife 330 in small angular increments to minimize a torque required to drive the rotating shaft 328 and smooth the torque demand on the drive system of the shredder system 200. Further, as shown in grouping 360, when a plurality of disc knives 330 are arranged together, knife hooks 332 and hub hooks 334 of adjacent disc knives 330 may be staggered like the disc knives 310 for the primary shredder 202.

[0039] In accordance with aspects herein, a shred size of the high security second shredded product 326 output by the secondary shredder 204 may be controlled by a width 338 of the disc knives 330, a height 340 of the knife hooks 332, and a height 342 of the hub hooks 334. For example, the width 338 of the disc knife 330 and the heights 340 and 342 of the knife hooks 332 and the hub hooks 334, respectively, may be decreased to produce an even smaller shred size. Each disc knife 330 may be about 9.0 mm to about 11.6 mm wide, about 9.2 mm to about 11.4 mm wide, about 9.3 mm to about 11.00 mm wide, and the like.

[0040] As shown in FIG. 3C, when the first shredded product 304 is outputted from the primary shredder 202 faster than the secondary shredder 204 can process, the first shredded product 304 can be accumulated (e.g., temporarily) in the overflow chamber 212 to relieve atleast some pressure that may arise from overfilling the collection chamber 208. In other words, the overflow chamber 212 allows the secondary shredder 204 to catch up.

[0041] In some examples, to assist with moving the first shredded product 304 to a position that is conducive to shredding by the secondary shredder 204, the shredder system 200 may further comprise an air knife 370 for pulsating fluid (e.g., air) into the collection chamber 208 in a direction shown by, for example, arrow 372. In examples, the bottom or lower wall of the overflow chamber 212 can be positioned to feed material (e.g., gravity fed) into the bite associated with the secondary shredder.

[0042] The air knife 370 can, in some instances, operate to blast compressed air against knives 330 of the shredder in order to dislodge material from the knife pockets or other recesses associated with the knives (e.g., hub pockets) or associated with the shredder. In some examples, the air knife 370 can be directed across the material flow path (e.g., across 208) or other plenum upstream of the shredder knives to direct the material towards the bite. In some instances, the air knife 370 can direct material into (or towards) the expansion chamber 212. In some examples, air knife 370 can direct air flow against the movable panel 214 to dislodge material.

[0043] The air knife can be operated consistently or at intervals. For instance, the air knife 370 may be activated when a pressure sensor of the primary shredder 202 senses that the primary shredder 202 is loaded. For example, the pressure sensor may trigger automatic activation of the air knife 370 when the pressure sensor senses that a pressure of the primary shredder 202 is equal to or above a threshold pressure . The threshold pressure may for example be at least 1000 psi. The air knife 370 may be configured to pulsate pressured air into the collection chamber 208 according to a predetermined sequencing pattern for a predetermined amount of time (e.g., 500 to 1000 milliseconds), or until the pressure sensor senses that apressure of the primary shredder 202 is below the threshold pressure for a predetermined amount of time (e.g. 5 seconds, such that when a pressure of the primary shredder 202 is below the threshold pressure for the predetermined amount of time, the air knife 370 is automatically turned off). For example, the sequencing pattern may cause the air knife to be on for 5 seconds followed by 2 seconds off.

[0044] Alternatively, or additionally, the secondary shredder 204 may also comprise a pressure sensor (not shown) configured to sense a load pressure on the secondary shredder 204. Operation of the air knife 370 may also be tied to operation of the secondary shredder 204. For example, the pressure sensor may trigger automatic activation of the air knife 370 when the pressure sensor senses that a pressure of the secondary shredder 204 is equal to or above a threshold pressure. The threshold pressure may for example be at least 1000 psi. Similar to the primary shredder 202, the air knife 370 may be configured to pulsate pressured air into the collection chamber 208 according to a predetermined sequencing pattern for a predetermined amount of time (e.g., 500 to 1000 milliseconds), or until the pressure sensor senses that a pressure of the secondary shredder 204 is below the threshold pressure for a predetermined amount of time (e.g. 5 seconds, such that when a pressure of the secondary shredder 204 is below the threshold pressure for the predetermined amount of time, the air knife 370 is automatically turned off).

[0045] In further aspects with accordance herein, FIG. 4 is an illustration showing a cross- sectional view through a second exemplary shredder system 400 having a primary shredder 404, a secondary shredder 406, a conveyor 426, and a collection chamber 428. The shredder system 400 operates in a manner similar to the corresponding shredders 100 and 200 discussed above with reference to FIG. 1 and FIG. 2A. To control the flow of the first shredded product 412 as it enters the secondary shredder 406, an outlet 422 of the primary shredder 404may be separated from an inlet 424 of the secondary shredder 406. In the depicted example, the conveyor 426 is positioned to receive the first shredded product 412 from at the outlet 422 of the primary shredder 404, and a collection chamber 428 is positioned to feed the first shredded product 412 towards an inlet 424 of the secondary shredder 406. In this context, feeding the first shredded product 412 “towards” the inlet 424 of the secondary shredder 406 does not necessarily require the conveyor 426 to move the first shredded product 412 in a particular direction, but may otherwise include advancing the first shredded product 412 through one or more steps such that at least a portion of the first shredded product 412 eventually arrives at the inlet 424 of the secondary shredder 406. For example, in the depicted embodiment, the conveyor 426 feeds the first shredded product 412 at an upward angle and then drops the first shredded product 412 into the collection chamber 428, which then directs the first shredded product 412 to the inlet 424 of the secondary shredder 406 with the assistance of gravity.

[0046] The conveyor 426 may include any suitable device(s) for moving a shredded paper product from one location to another. In the depicted embodiment, the conveyor 426 includes a movable surface 430 (which may be a belt drive or another suitable surface that physically contacts the first shredded product), but other structures may be alternatively (or additionally) included. For example, it is contemplated that the conveyor 426 may operate via air pressure that blows the first shredded product from one location to another without requiring direct mechanical contact between the conveyor 426 and the paper particles of the first shredded product 412. In some embodiments (such as the embodiment of FIG. 7), the conveyor 426 may communicate with a sorter to remove components from the first shredded product 412 that are undesirable or unsuitable for manipulation by the secondary shredder 406.

[0047] The collection chamber 428 may be configured (e.g., sized, shaped, positioned, and / or oriented) to limit or otherwise affect the flow of the first shredded product 412 as it enters the secondary shredder 406 at the inlet 424. For example, the collection chamber 428 may have a vertical dimension such that the first shredded product 412 falls towards the inlet 424 for a particular distance (e.g., such that the first shredded product 412 generally approaches a terminal vertical velocity), and / or such that adequate space is provided to avoid compacting the first shredded product 412 inside the collection chamber 428. In some embodiments, a track or other path may be created with a structural component, such as an angled wall 432. When included, at least a portion of the first shredded product 412 may slide down the angled wall 432 such that it has a predictable and repeatable rate of flow as it approaches the inlet 424 of the secondary shredder 406. It is contemplated that the surface of the angled wall 432 may be lubricated, polished, textured, and / or otherwise manipulated in an attempt to optimize the rate of flow of the first shredded product 412 as it moves through the collection chamber 428.

[0048] Optionally, a discharge chute 434 may be located adjacent to the outlet 422 of the primary shredder 404, particularly when the primary shredder 404 ejects / outputs the first shredded product 412 at a high flow rate. The discharge chute 434 may be configured (e.g., shaped, sized, located, and / or oriented) to catch the first shredded product 412 as it exits the primary shredder 404 such that it then collects on a first end 436 of the conveyor 426. One advantage of including the discharge chute 434 is that it may allow the angle A of discharge to tilt away from the secondary shredder 406 (relative to the “true vertical” as defined by the direction of gravity). Such an orientation may provide more efficient assembly, maintenance, and efficient packaging of the shredder system 402. For example, this orientation may be advantageous when the primary shredder 404 is fitted to a large hopper 440 that requires oneor more rotors 416 of the primary shredder 404 to be located at a hopper discharge opening 442 (with an appropriate orientation).

[0049] Similarly, a feed chute 444 may be located at a second end 438 of the conveyor 426. The feed chute 444 may adjacent to the entrance 446 of the collection chamber 428 and configured (e.g., shaped, sized, located, and / or oriented) to receive the first shredded product 412 from the conveyor 426 and to direct the first shredded product 412 into collection chamber 428. As shown, the feed chute 444 may be integral with the collection chamber 428. Additionally or alternatively, the feed chute 444 may be separate from the collection chamber 428, and may act as (or communicate with) an optional funnel that directs the first shredded product 412 into the collection chamber 428 (and / or towards a particular feature within the collection chamber 428, such as the angled wall 432 discussed above) with the assistance of gravity.

[0050] Optionally, the inlet 424 of the collection chamber 428 may be located above the outlet 422 of the primary shredder 404. Thus, the conveyor is angled such that feeding the first shredded product to the inlet 424 of the collection chamber 428 causes the first shredded product to ascend relative to the true horizontal (where “true horizontal” is defined as a plane perpendicular to gravitational force, which is typically parallel to the ground).

[0051] FIG. 5 shows an embodiment similar to that of FIG. 4, but where certain components are relocated such that the shredder system 500 fits in a relatively compact package (e.g., for a mobile application). For example, the primary shredder 504 is located approximately above the secondary shredder 506. When operating, the outlet 522 of the primary shredder 504 is angled such that it dispenses / ejects the first shredded product 512 directly onto the conveyor 536 (e.g., without the need for a discharge chute 534, for example). Notably, relative to the true vertical,the angle A of discharge is tilted towards the secondary shredder 506 in this embodiment (which contrasts with the embodiment of FIG. 4).

[0052] FIG. 6 shows another embodiment of the shredder system 600. As shown, the embodiment of FIG. 6 lacks the conveyor 626 shown in FIG. 4. Instead, the primary shredder 604 of FIG. 6 is re-positioned such that the outlet 622 of the primary shredder 604 is located above the inlet 624 ofthe secondary shredder 606. The collection chamber 628 receives the first shredded product 612 as it exits the primary shredder 604 and acts as a chute such that the collection chamber 628 directs the first shredded product 612 to the inlet 624 of the secondary shredder 606 with the assistance of gravity. Optionally, the angled wall 632 (which may be curved, as shown, in certain applications) may be included to further control the rate of flow towards the inlet 624.

[0053] To prevent the first shredded product 612 from becoming compacted inside the collection chamber 628, a gate 650 may be included that prevents the collection chamber 628 from being overfilled. For example, when the accumulation of the first shredded product 612 reaches a certain level within the collection chamber 628, the accumulation may force the gate to close, thereby preventing further first shredded product 612 from entering the collection chamber 628. The gate 650 may communicate with a control system (now shown) such that closure of the gate 650 causes the primary shredder 604 to shut down or reduce its operational speed, for example. Additionally or alternatively, an overflow chamber 652 may be included that captures the first shredded product 612 that fails to enter the collection chamber 628. The gate 650, overflow chamber 652, and / or the other related features may be included in any other embodiment, where compatible.

[0054] FIG. 7 shows an embodiment of the shredder system 700 shown in FIG. 4 with the inclusion of a sorter 760 in communication with the conveyor 726. For example, the sorter 760may be located along the conveyor 726 somewhere between the first end 736 and the second end 738 such that a sorting operation is accomplished on the first shredded product 712 (e.g., after exiting the first shredder 704) prior to entering the collection chamber 728. An alternative (or additional) sorting operation may occur within the collection chamber 728 (or elsewhere).

[0055] The sorter 760 may include any suitable structure for sorting various particles within the first shredded product 712. Without limitation, in one aspect, the sorter 760 includes one or more openings that are selectively sized to capture particles of a certain size. For example, particles that have a suitable size for entering the secondary shredder 706 may continue to the collection chamber 728, while those that are too large may be directed elsewhere (perhaps back to the hopper 740). It is contemplated that the sorter 760 (or entire conveyor 726) may shake / vibrate to facilitate movement of the large particles through the sorter’s openings. Additionally or alternatively, the sorter 760 may sort out particles having a certain weight (or density) from paper particles through a suitable method, such as by utilizing vibrations and / or centrifugal motion to gather particles having a density over a certain threshold. Advantageously, such an operation may remove non-paper matter from the first shredded product 712, such as staples, cardboard, ring binder materials, etc. When it is specifically desirable to remove metals, the sorter 760 may include a magnet, for example. Removal of such materials may prevent damage to the secondary shredder 706 and may allow the secondary shredder 706 to be more efficiently designed and calibrated for paper shredding performance without certain parameters and limitations.Example Clauses

[0056] As used herein, a recitation of “and / or” with respect to two or more elements should be interpreted to mean only one element, or a combination of elements. For example, “element A, element B, and / or element C” may include only element A, only element B, onlyelement C, element A and element B, element A and element C, element B and element C, or elements A, B, and C. In addition, “at least one of element A or element B” may include at least one of element A, at least one of element B, or at least one of element A and at least one of element B. Further, “at least one of element A and element B” may include at least one of element A, at least one of element B, or at least one of element A and at least one of element B.

[0057] Clause 1. A shredder system comprising: a primary shredder for forming a first shredded product; and a secondary shredder for shredding the first shredded product to form a second shredded product; a collection chamber located at an outlet of the primary shredder and positioned to feed the first shredded product towards an inlet of the secondary shredder; a overflow chamber fluidly connected with the collection chamber configured to accumulate the first shredded product waiting to be fed to the secondary shredder; and wherein the collection chamber includes a pivoting wall.

[0058] Clause 2. The shredder system of clause 1, wherein the pivoting wall is hingedly secured to the shredder system, wherein the pivoting wall has a first position and a second position.

[0059] Clause 3. The shredder system of clause 2, wherein the pivoting wall is in the first position when the secondary shredder is deactivated, and wherein the pivoting wall is in the second position when the secondary shredder is activated.

[0060] Clause 4. The shredder system of clause 3, wherein in the second position, the pivoting wall is to contact the first shredded product to lead the first shredded product toward the secondary shredder.

[0061] Clause 5. The shredder system of clause 3 or clause 4, wherein in the first position, a planar surface of the pivoting wall is substantially parallel to a wall of the collection chamber.

[0062] Clause 6. The shredder system of any of clauses 3 to 5, wherein the second position, a planar surface of the pivoting wall is lifted from a wall of the collection chamber such that it forms an angle defined by the planar surface of the pivoting wall and the wall of the collection chamber.

[0063] Clause 7. The shredder system of any of clauses 2 to 6, wherein in the first position, a passage from the collection chamber to an auger of the shredder system is open, and wherein in the second position, the passage is closed by the pivoting wall.

[0064] Clause 8. The shredder system of any of clauses 1 to 7, further comprising a first pressure sensor configured to sense a load on the primary shredder.

[0065] Clause 9. The shredder system of clause 8, further comprising an air knife.

[0066] Clause 10. The shredder system of clause 9, wherein the air knife is activated when a first threshold pressure is detected by the first pressure sensor.

[0067] Clause 11. The shredder system of clause 10, further comprising a second pressure sensor configured to sense a load on the secondary shredder.

[0068] Clause 12. The shredder system of clause 11, wherein the air knife is deactivated when a second threshold pressure is detected in the second pressure sensor.

[0069] Clause 13. The shredder system of any of clauses 1 to 12, wherein the first shredded product comprises a first shred size that is larger than a second shred size of the second shredded product.

[0070] Clause 14. The shredder system of any of clauses 9 to 13, wherein the air knife is fluidly connected to a pressurized air source and is configured to break down clumps formedfrom the first shredded product and push the first shredded product toward the overflow chamber.

[0071] Clause 15. The shredder system of clause 14, wherein the air knife is configured to deliver pulses of pressurized air to the collection chamber.

[0072] Clause 16. The shredder system of any of clauses 1 to 15, wherein the primary shredder comprises two sets of primary blades, each set comprising a first number of primary blades.

[0073] Clause 17. The shredder system of clause 16, wherein the secondary shredder comprises a set of secondary blades comprising a second number of secondary blades.

[0074] Clause 18. The shredder system of claims 16 or clause 17, wherein each of the first number of primary blades comprises a first number of cutting edges.

[0075] Clause 19. The shredder system of clause 18, wherein each of the secondary blades comprises a second number of cutting edges.

[0076] Clause 20. The shredder system of clause 19, wherein each of the secondary blades comprises major cutting edges and minor cutting edges.

[0077] Clause 21. The shredder system of clause 19, wherein the second number of cutting edges is greater than the first number of cutting edges.

[0078] Clause 22. A shredder system comprising: a primary shredder; and a secondary shredder; a conveyor positioned to receive a first shredded product from at an outlet of the primary shredder; and a collection chamber positioned to feed the first shredded product towards an inlet of the secondary shredder, wherein the conveyor is configured to move the first shredded product from the outlet of the primary shredder to the collection chamber.

[0079] Clause 23. The shredder system of clause 22, wherein the collection chamber includes an angled wall configured to direct the first shredded product towards the inlet of the secondary shredder.

[0080] Clause 24. The shredder system of clause 22 or clause 23, further comprising a discharge chute located adjacent to the outlet of the primary shredder and configured to direct the first shredded product onto the conveyor.

[0081] Clause 25. The shredder system of any of clauses 22 to 24, further comprising a feed chute located adjacent to an entrance of the collection chamber and configured to receive the first shredded product from the conveyor and direct the first shredded product into the collection chamber.

[0082] Clause 26. The shredder system of any of clauses 22 to 25, wherein the inlet of the collection chamber is located above an outlet of the primary shredder.

[0083] Clause 27. The shredder system of clause 26, wherein the conveyor is angled such that feeding the first shredded product to the inlet of the collection chamber causes the first shredded product to ascend relative to the true horizontal.

[0084] Clause 28. The shredder system of any of clauses 22 to 27, wherein a discharge path from the outlet of the primary shredder tilts away from the secondary shredder relative to the true vertical.

[0085] Clause 29. The shredder system of any of clauses 22 to 28, wherein the primary shredder is configured to shred paper into a first larger shred size material, and wherein the secondary shredder is configured to further shred the first larger shred size material into a second smaller shred size material.

[0086] Clause 30. The shredder system of any of clauses 22 to 29, wherein the collection chamber communicates with a funnel configured to direct the first shredded product into the collection chamber.

[0087] Clause 31. The shredder system of any of clauses 22 to 30, further comprising a sorter located between the primary shredder and the secondary shredder, wherein the sorter is configured to remove at least one particle type from the first shredded product.

[0088] Clause 32. A shredder system comprising: a primary shredder for forming a first shredded product; and a secondary shredder for shredding the first shredded product to form a second shredded product; and a collection chamber located at an outlet of the primary shredder and positioned to feed the first shredded product towards an inlet of the secondary shredder, wherein the collection chamber includes a wall that is angled relative to the true vertical direction, the angled wall being configured to contact the first shredded product to lead the first shredded product to the inlet of the secondary shredder.

[0089] Clause 33. The shredder system of clause 32, further comprising funnel for directing the first shredded product from the outlet of the primary shredder to the collection chamber.

[0090] Clause 34. The shredder system of clause 32 or clause 33, wherein the inlet of the collection chamber is located above an outlet of the primary shredder.

[0091] Clause 35. The shredder system of any of clauses 32 to 34, wherein the primary shredder is configured to shred paper into a first larger shred size material, and wherein the secondary shredder is configured to further shred the first larger shred size material into a second smaller shred size material.

[0092] Clause 36. The shredder system of any of clauses 32 to 35, further comprising a sorter located between the primary shredder and the secondary shredder, wherein the sorter is configured to remove at least one particle type from the first shredded product.

[0093] Clause 37. The shredder system of any of clauses 32 to 36, wherein a gate is located at an entrance of the collection chamber, and wherein the gate is configured to prevent the first shredded product from entering the collection chamber when the collection chamber is full.

[0094] Clause 38. A shredder system comprising: a primary shredder; and a secondary shredder; a conveyor positioned to receive a first shredded product from at an outlet of the primary shredder; and wherein the conveyor is configured to move the first shredded product from the outlet of the primary shredder towards an inlet of the secondary shredder.

[0095] Clause 39. The shredder system of clause 38, further comprising a discharge chute located adjacent to the outlet of the primary shredder and configured to direct the first shredded product onto the conveyor.

[0096] Clause 40. The shredder system of clause 38 of clause 39, further comprising a sorter located between the primary shredder and the secondary shredder, wherein the sorter is configured to remove at least one particle type from the first shredded product.

[0097] Clause 41. The shredder of any of clauses 38 to 40, wherein the conveyor includes a movable surface for displacing the first shredded product.

[0098] Clause 42. A shredder comprising: a rotor comprising knives; an air knife comprising one or more jets oriented towards the knives.

[0099] Clause 43. A shredder comprising: a rotor comprising knives positioned to engage material at a bite; one or more material aligners positioned upstream of the knives; and the one or more material aligners comprising a surface angled towards the bite.

[0100] The subject matter of embodiments of the present invention is described with specificity herein to meet statutory requirements. However, the description itself is not intended to limit the scope of this patent. Rather, the inventor(s) have contemplated that the claimedsubject matter might also be embodied in other ways, to include equivalent and / or different features or combinations of features similar to the ones described in this document, in conjunction with other present or future technologies. It should be understood that in certain instances, details have been omitted which are not necessary for an understanding of the present invention, such as conventional fabrication and assembly. Further, it should be appreciated that the figures do not necessarily represent an all-inclusive representation of the embodiments herein and may have various components hidden to aid in the written description thereof. While various embodiments of the invention have been described, the invention is not to be restricted except in light of the attached claims and their equivalents. Moreover, the advantages described herein are not necessarily the only advantages of the invention and it is not necessarily expected that every embodiment of the invention will achieve all of the advantages described.

Claims

CLAIMSWhat is claimed is:

1. A shredder system comprising: a primary shredder configured to output a first shredded product; a secondary shredder configured to shred the first shredded product an output a second shredded product; a collection chamber positioned at an outlet of the primary shredder, wherein the collection chamber comprises an opening for the first shredded product to at least partially bypass shredding by the secondary shredder; a movable panel that is movable between a first position that blocks the opening and a second position that unblocks the opening, wherein the collection chamber is configured to direct the first shredded product towards the secondary shredder when the movable panel is in the first position; and an overflow chamber fluidly connected with the collection chamber and configured to at least temporarily contain the first shredded product prior to shredding by the secondary shredder.

2. The shredder system of claim 1, wherein the movable panel is hingedly secured to the shredder system.

3. The shredder system of claim 2, wherein the movable panel comprises the first position when the secondary shredder is activated, and wherein the movable panel comprises the second position when the secondary shredder is deactivated.

4. The shredder system of any of claims 1 to 3, wherein the overflow chamber is configured to direct the first shredded product towards a bite of the secondary shredder.

5. The shredder system of any of claims 1 to 4 further comprising an air knife configured to direct pressurized fluid towards the primary shredder, the secondary shredder, the collection chamber, or any combination thereof.

6. The shredder system of claim 5, wherein the air knife is configured to direct the first shredded product towards the overflow chamber.

7. The shredder system of claim 5 or claim 6, wherein the air knife is configured to blow the first shredded product off the movable panel.

8. The shredder system of any of claims 1 to 7, wherein the primary shredder comprises a plurality of knives that are secured to a rotor, and wherein the shredder system further comprises one or more fingers that are fixed relative to the rotor and that are positioned in a gap between adjacent knives of the plurality of knives.

9. The shredder system of claim 8, wherein the one or more fingers are configured to dislodge first shredded product from the gap.

10. The shredder system of any of claims 1 to 9, wherein the primary shredder comprises a bite, and wherein the shredder system further comprises one or more material aligners positioned upstream of the primary shredder, the one or more material aligners comprising a surface angled towards the bite.

11. A method of shredding a material, the method comprising: shredding the material with a primary shredder to form a first shredded product; outputting the first shredded product into a collection chamber; directing the first shredded product from the collection chamber into an overflow chamber; feeding the first shredded product from the overflow chamber to a secondary shredder; and shredding the first shredded product with the secondary shredder to form a second shredded product.

12. The method of claim 11, wherein the collection chamber comprises an opening through which the first shredded product bypasses the secondary shredder, and wherein the method further comprises closing the opening with a movable panel.

13. The method of claim 11 or claim 12 further comprising, directing, via an air knife, a pressurized fluid into the collection chamber.

14. The method of claim 13, wherein the pressurized fluid at least partially directs the first shredded product to the overflow chamber.

15. The method of claim 13 or claim 14 further comprising, determining via a load sensor that a load associated with the primary shredder or the secondary shredder exceeds a threshold, wherein the pressurized fluid is directed into the collection chamber based on the threshold being exceeded.

16. The method of any of claims 11 to 15 , wherein the first shredded product is gravity fed from the overflow chamber to a bite of the secondary shredder.

17. A shredder system comprising: a primary shredder configured to output a first shredded product; a secondary shredder configured to shred the first shredded product and output a second shredded product, which is smaller than the first shredded product; a collection chamber positioned at an outlet of the primary shredder, wherein from the collection chamber, the first shredded product is directed towards the secondary shredder; and an overflow chamber fluidly connected with the collection chamber and configured to at least temporarily contain the first shredded product prior to shredding by the secondary shredder.

18. The shredder system of claim 17 further comprising an air knife configured to direct pressurized fluid towards the primary shredder, the secondary shredder, the collection chamber, or any combination thereof.

19. The shredder system of claim 18, wherein the air knife is configured to direct the first shredded product towards the overflow chamber.

20. The shredder system of any of claims 17 to 19, wherein the primary shredder comprises a plurality of knives that are secured to a rotor, and wherein the shredder system further comprises one or more fingers that are fixed relative to the rotor and that are positioned in a gap between adjacent knives of the plurality of knives.

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