Removable disc construction for disc screen apparatus

Information

  • Patent Grant
  • 6318560
  • Patent Number
    6,318,560
  • Date Filed
    Thursday, February 15, 2001
    24 years ago
  • Date Issued
    Tuesday, November 20, 2001
    23 years ago
Abstract
A disc screen apparatus is disclosed for separating mixed recyclable materials of varying sizes and shapes. The disc screen apparatus has an enclosure or frame with an input, a container discharge location and a paper discharge location. A first plurality of shafts and second plurality of shafts are rotatably supported by the frame. The first plurality of shafts form a first disc screen disposed in a first plane and the second plurality of shafts form a second disc screen at least a portion of which is disposed in a second plane. The second plane is disposed beneath and angled with respect to the first plane such that the planes at least partially overlap. One or more motors rotate the first and second plurality of shafts. Each shaft has a plurality of discs positioned along it. The discs are offset between adjacent shafts such that discs on each shaft interleave with discs on an adjacent shaft but do not touch the adjacent shaft. The discs are substantially square in shape with radiused corners. The radiused corners have a texture, such as ridges. The arrangement of the discs on the shafts creates a screening pattern capable of screening a portion of the mixed recyclable materials. Each disc is assembled about a shaft from two identical portions. The portions are clamped together, about the shaft to form the disc. If the disc is damaged or worn, it may be removed from the shaft for repair or replacement without disassembly of the shaft from the apparatus or removal of other discs. The discs are also disclosed as comprising an inner rigid frame supporting an outer, softer material.
Description




BACKGROUND OF THE INVENTION




The invention is in the field of machines for processing recyclable material, and particularly concerns machines that separate paper, bulk containers, broken glass and other materials.




More specifically, the invention relates to a disc screen apparatus for classifying material in a stream of heterogeneous materials. More specifically still, the invention concerns a disc screen apparatus with discs that may be mounted to and removed from the apparatus without disassembly of the apparatus.




Material recycling has become an important industry in recent years due to decreasing landfill capacity, environmental concerns and the dwindling of natural resources. Many industries and communities have adopted voluntary and mandatory recycling programs for reusable materials. Solid waste and trash that is collected from homes, apartments or companies often combine the recyclable materials into one container, usually labeled “RECYCLABLE MATERIAL”. Recyclable materials include newspaper, magazines, aluminum cans, glass bottles and other materials that may be recycled. When brought to a processing center, the recyclable materials are frequently mixed together in a heterogenous mass of material. Ideally, the mixed materials should be separated into common recyclable materials (i.e., papers, cans, etc.).




Disc screens are increasingly used to separate heterogeneous streams of recyclable material into respective streams or collections of similar materials. This process is referred to as “classifying”, and the results are called “classification”.




A disc screen apparatus typically includes a frame in which a plurality of rotatable shafts are mounted in parallel. A plurality of discs are mounted on each shaft and means are provided to rotate the shafts commonly in the same direction. The discs on one shaft interleave with the discs on an adjacent shaft to form screen openings between the peripheral edges of the discs and structures on the adjacent shaft. The sizes of the openings determine the size (and thus the type) of material that will fall through the screen. Rotation of the discs carries the larger articles along or across the screen in a general flow direction from an input where a stream of material pours onto the disc screen to an output where those articles pour off of the disc screen.




In disc screen apparatuses that are used for classification of recyclable materials I have found that the heavy continuous flow of recyclable material tends to result in quick wear and a significant degree of damage to the discs, requiring a high level of maintenance and repair. My observation is that the discs are typically slidably engaged to their shafts, fixed in their positions by spacers, and retained in the shafts by clamping applied to the ends of the shafts. Therefore, to replace a damaged disc, the shaft on which the disc is mounted must be disassembled from the screen, the disc slid off the shaft and replaced, and the shaft reassembled to the screen. Much time is consumed in this process.




SUMMARY OF THE INVENTION




The invention is based upon the critical realization that a disc for a disc screen apparatus can be provided in two (or more) matching pieces having opposing surfaces that are clamped together around a shaft. When damaged, the matching pieces are separated, removed from the shaft and replaced by the pieces of another, undamaged disc.




In connection with this objective, the invention is directed toward provision of a disc that can be attached to and removed from the shaft of a disc screen apparatus without disassembling the shaft from the screen apparatus.




Other objects and advantages of the invention will become apparent when the following detailed description is read with reference to the below-described drawings.











BRIEF DESCRIPTION OF THE DRAWING





FIG. 1

is a side view of a disc screen machine that embodies the invention;





FIGS. 2A-2C

are top views of rotatable shafts and discs showing different screen configurations;





FIG. 3A

is a side elevation view of a disc, with a portion cut away, showing certain elements with hidden lines;





FIG. 3B

is an elevation view of an edge of the disc of

FIG. 3A

;





FIG. 3C

is a top plan view of an edge of the disc of

FIG. 3A

;





FIG. 4A

is a side elevation view, with a portion cut away, of one of two pieces of the disc of

FIG. 3A

;





FIG. 4B

is an end elevation view of the one piece of

FIG. 4A

;





FIG. 4C

is sectional view of the one piece, taken along C—C of

FIG. 4A

;





FIG. 5A

is a side elevation view of a rigid frame or an embedment in the one piece of

FIG. 4A

;





FIG. 5B

is a front elevation view of the embedment of

FIG. 5A

;





FIG. 5C

is a sectional view of the embedment of

FIG. 5A

, taken along C—C of

FIG. 5A

;





FIG. 6

is a top view taken along


6





6


in

FIG. 1

showing the relationship of the motor, rotatable shafts, pulleys and drive mechanism;





FIGS. 7A

,


7


B and


7


C are views of a shaft assembly; and





FIGS. 8A and 8B

show some details of the shaft assembly in FIG.


7


.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT




My invention is a disc screen apparatus (“hereinafter “apparatus”) that separates mixed recyclable materials, of various sizes and shapes, including paper, magazines, plastic or aluminum containers and the like. The apparatus, indicated generally by


100


, includes a frame (or housing)


102


, having a first plurality of rotatable shafts


108


(“first rotatable shafts”) and a second plurality of rotatable shafts


112


(“second rotatable shafts”) rotatably supported in the frame


102


. A first motor


118


mounted on the frame


102


is coupled to a drive chain


119


that imparts a rotational force to the first rotatable shafts


108


, while a second motor


130


, also mounted on the frame


102


, is coupled to a drive chain


131


that imparts a rotational force to the second rotatable shafts


112


.




Preferably, the frame


102


is constructed using durable, heavy duty materials, such as steel. The precise shape of the frame


102


, and its structure and layout, are subject to the design considerations and operational constraints of any particular application. However, in this example the frame


102


is a generally closed structure with an mixed material input area


104


, container discharge area


114


and a paper discharge area


116


.




Although the frame


102


forms an enclosure, this is not absolutely necessary to the invention, but it may be required for safety reasons. The mixed material input area


104


is generally located near a first end


105


of the frame


102


, where a heterogenous material stream


106


of recyclable materials enters the apparatus. As can be seen in

FIG. 1

, the material stream


106


travels through the mixed material input area


104


, and falls onto the first rotatable shafts


108


. The first rotatable shafts


108


rotate in such a direction that the material stream


106


travels from the first end


105


of the apparatus toward a second end


107


of the apparatus in a general flow direction. Mounted on the first rotatable shafts


108


are a plurality of discs


110


that both agitate and propel the material stream


106


. The discs


110


may be spaced on the shafts in a variety of patterns. Depending on the patterns of the discs


110


, the material stream


106


starts to separate in one way or another. In this manner, the first rotatable shafts


108


with discs


110


act as a first disc screen. (Hereinafter, these terms are interchangeable.) In the preferred embodiment, the discs


110


are positioned in the first disc screen so that the material stream


106


is initially screened, with small materials


120


passing through the openings and larger materials continuing along the first rotatable shafts


108


, all the while being agitated by the discs


110


. At the end of the plane of first rotatable shafts


108


, the larger materials fall onto the second rotatable shafts


112


(the direction shown as arrow


124


). Mounted on the second rotatable shafts


112


are a plurality of discs


110


. Thus, the second rotatable shafts with discs


110


act as a second disc screen, and these terms are interchangeable hereinafter. The discs


110


may be mounted on the second rotatable shafts in a variety of patterns. The second rotatable shafts


112


are generally positioned in an inclined plane


160


that has an angle


162


. This inclined arrangement of the second rotatable shafts


112


allows heavier objects


122


, such as bottles and cans, to bounce on the discs


110


and tumble backward and downward toward the container discharge area


114


, finally falling out of the container discharge area


114


into a container or plenum


150


. Lighter material such as cardboard and paper falling on the second disc screen does not bounce and is carried toward and upwardly to the paper discharge area


116


. To assist in propelling the paper


126


toward the paper discharge area


116


, one or more fans


128


may be mounted near the first end


105


of the frame to blow air


130


at the second rotatable shafts


112


.





FIGS. 2A

,


2


B and


2


C show examples of the discs


110


mounted on the first and second rotatable shafts


108


and


112


, with varied spacing, creating a variety of screen patterns.

FIGS. 2A and 2B

show examples of two screen patterns


202


and


204


of the discs


110


mounted on the first rotatable shafts


108


.

FIG. 2A

shows the discs


110


mounted on the shaft in a fine screen pattern, with small spaces between the edges of the discs


110


and adjacent shafts. One such space is indicated by


204


. This fine screen pattern


202


is used in the apparatus where small materials are screened. In

FIG. 2B

, the discs


110


are mounted in a gross screen pattern


206


with large openings such as


208


such that larger, heavier materials are able to fall through the openings


208


between the discs


110


. In some cases, it may be desirable to have a combination of spacings between the discs (i.e., have both small openings


204


and large openings


208


). In this way, as the material stream travels along a plurality of rotating shafts, the mixed material is separated and screened in successive stages on one disc screen. One example combination pattern formed by varying the screen patterns is shown in FIG.


2


C. In fact, this pattern describes the layout of the first disc screen. In this regard, as the material stream pours onto the disc screen apparatus in the inlet are


104


on the fine screen pattern


202


, the material stream is agitated and moved by rotation of the discs with the shafts toward and over the gross screen pattern


206


. Over the fine screen pattern


202


, relatively fine grit, glass shards, and other small materials are screened out. Over the gross screen pattern


206


, larger objects such as cans, bottles, and envelopes pour through the larger openings onto the lower end of the second rotatable shafts


112


. In the preferred embodiment, the entire second disc screen has the gross screen pattern


206


of FIG.


2


B.




In the apparatus


100


, the first and second rotatable shafts


108


and


112


extend through and are supported between sides


136


(near side shown in

FIG. 1

) and


138


(far side) of the frame


102


. The first rotatable shafts


108


are located in a first plane and the second rotatable shafts


112


are located below and partially underneath the first rotatable shafts


108


in an overlapping manner, with the first three shafts


112




a


,


112




b


, and


112




c


defining a plane that is parallel to that of the first rotatable shafts


108


, and the remaining twelve defining a second plane. In the preferred embodiment, the first plane is generally disposed at a slight incline from horizontal to assist in the initial separation of the material stream


106


. The first plane angle may vary from 0 to 45 degrees, with the preferred embodiment angle being 20 degrees. The second plane is generally disposed at an inclined angle such that the larger objects


122


do not readily go up the incline. The angle may vary from 25 to 60 degrees with the preferred embodiment angle being 35 to 45 degrees. In one embodiment, the frame


102


is mounted at a fixed first point


132


and a rotatable second point


133


. The frame


102


may be rotated up or down, with the first point


132


as the pivot point, to alter an incline angle of the frame


102


using a jack


134


at the second point


133


. This rotation of the frame up or down may also be used to vary the angles of the shafts.




The number of shafts is dependent on the size of the machine


100


and on intershaft spacing. In the embodiment shown in

FIG. 1

, the number of shafts in the first plurality of rotatable shafts


108


is less than the number of shafts in the second plurality of rotatable shafts


112


. In the

FIG. 1

, there are eight first rotatable shafts


108


and fifteen second rotatable shafts


112


. The first shafts


108


and second shafts


112


are supported by bushings or bearings


140


positioned along sides


136


and


138


.




The plurality of discs


110


, made from a hard durable material with a high coefficient of friction, such as rubber, are mounted on the first rotatable shafts


108


and the second rotatable shafts


112


to form the screen patterns shown in

FIGS. 2A-2C

; however, the discs


110


may be mounted along the first rotatable shafts


108


and the second rotatable shafts


112


in a variety of spacing patterns. The discs


110


on adjacent shafts are offset on their respective shafts such that the discs


110


on one shaft fit between (interleave with) the discs on the other shaft without touching the other shaft. This is best seen in

FIGS. 2A-2C

.




Referring again to

FIGS. 1 and 6

, in the preferred embodiment, the first motor


118


and second motor


130


are positioned on the side


138


(far side) of the frame


102


. The motors


118


and


130


are shown with dashed lines. A drive chain


119


attaches between the motor


118


and a drive sprocket


142


mounted on the end of the first shaft


108




a


that is on the side of


138


(far side). A plurality of rotation sprockets


144


are mounted at the end of each first shaft


108


, that is on the side


136


(near side). A rotation chain


146


interconnects the plurality of rotation sprockets


144


, as shown in

FIG. 1. A

drive chain


131


attaches between the motor


130


and a drive sprocket


142


on the end of the second shaft


112


that is on the side


138


(far side). A plurality of rotation sprockets


144


are located at the end of each second shaft


112


on side


136


(near side). A rotation chain


148


interconnects the plurality of rotation sprockets


144


. Safety covers (not shown) cover the plurality of rotation sprockets and rotation chains. There may also be access doors or panels


151


on the sides


136


and


138


to allow access or viewing of the interior of the machine.




The first motor


118


turns the drive chain


119


and drive sprocket


142


, thereby rotating the first rotatable shaft


108




a


in a first direction. Since all of the first rotatable shafts


108


are interconnected by rotation sprockets


144


and rotation chain


146


, all of the first rotatable shafts


108


rotate together in the first direction at the same speed. The second motor


130


turns the drive chain


131


and drive sprocket


142


, thereby rotating the second rotatable shaft


112


in a second direction. Since all of the second rotatable shafts


112


are interconnected by rotation sprockets


140


and rotation chain


148


, all the second rotatable shafts


112


rotate together in the second direction at the same speed. The rotating second direction of the second rotatable shafts


112


is in the same direction as the rotating first direction of the first rotatable shafts


108


. Each motor may rotate its plurality of shafts at a particular speed. In the illustrative embodiment, the rotation speed of the first rotatable shafts


108


is around 60-100 revolutions per minute (rpm) and the rotation speed of the second rotatable shafts


112


is around 200-300 rpm. Although the preferred embodiment couples the motors to the shafts by sprocket/chain drives, other couplings may be used including, but not limited to, transmission couplings, geared couplings, direct couplings, and so on. Alternatively, separate individual shafts may be powered by separate individual motors. Further, the motors may be stationed at positions other than those shown, both on and off the frame


102


as design and installation considerations dictate. The sizes of the motors are dependent on a number of factors such as the number of rollers, type of drive mechanism, and so on. For example, each may have a rating of around 3 HP, with a 90 degree worm drive.




The operation of the disc screen apparatus


100


is as follows. Initially, the material stream


106


pours upon the first disc screen in the material entry area


104


. In the fine screen section


202


of the first disc screen, the material stream is agitated and small matter is screened out, falling downwardly through the apparatus


100


to be collected by conventional means. The material stream


106


is propelled upwardly by the rotation of the discs toward, over, and off of the gross screen section


206


. As it passes over the gross screen section


206


, intermediate-sized objects such as cans, twelve-ounce bottles and envelopes fall through the gross mesh onto to the lower end of the second rotatable shafts


112


. Meanwhile, the larger objects including large containers, newspapers, and cardboard sections of the material stream


106


are propelled off the upper end of the first disc screen onto the midsection of the second disc screen. Thus, the material stream


106


pours onto the second disc screen for screening already in a somewhat differentiated state, with smaller objects falling onto the lower rear portion of the second disc screen, and larger objects onto its midsection. The smaller objects are screened at the lower portion of the second disc screen, either passing through the gross screen pattern into the plenum


150


or tumbling downwardly off the lower end of the second disc screen into the plenum


150


. The larger objects that pour onto the midsection of the second disc screen separate, with the larger, heavier objects such as large bottles and plastic containers being bounced off the screen and rolling downwardly toward the lower end of the second disc screen from which they fall into the plenum


150


. Meanwhile, the larger light objects such as newspapers, magazines, and cardboard sections are carried upwardly by rotation of the second rotatable shafts


112


toward, over, and off of the upper end of the second disc screen from which they fall onto a collection conveyor


152


. A distinct advantage of this operation is that the material stream


106


is classified essentially into three sections on the first disc screen. Advantageously, the second disc screen receives a material stream that has been partially classified into smaller heavier objects that pour onto the lower portion of the second disc screen and a mixture of larger heavy and light objects that pour onto the second disc screen in its midsection. This avoids the prior art problem of a single, large, very dense stream of material pouring onto a single disc stream, creating a large eddying slurry of undifferentiated material at its impact point. As is known, such a large slurry reduces the effectiveness of a disc screen, providing less sharply differentiated collections of material than are afforded by the apparatus


100


.





FIGS. 3A-3C

show details of a preferred embodiment of a disc


110


. The disc


110


is designed to be replaceable on a shaft, without disassembly of the shaft and/or removal of other discs therefrom. The disc


110


is designed to separate into two portions at a separation plane


306


into disc portion


302




a


and disc portion


302




b


. Screws


304


clamp the disc halves


302




a


and


302




b


together. A central opening


308


of the disc


110


is designed to fit on the rotatable shafts


108


or


112


. The central opening


308


comprises planar sections


310


. As can be seen in the figures, the rotatable shafts


108


or


112


are eccentric (preferably square) in configuration. This provides more planar contact between the rotatable shaft and the disc. Because of the design of the disc


110


, as the disc halves


302




a


and


302




b


are clamped around the rotatable shaft


108


or


112


, the planar sections


310


make contact with the flat sides of the rotatable shafts at four clamping surfaces


312


. This allows the disc


110


to clamp or grab a shaft


108


or


112


such that it will not freely spin on the shaft. This clamping design also eliminates the need for spacers or the like to be positioned between the discs


110


to create the desired screen patterns.




The disc


110


is (preferably) square in shape with an outer peripheral edge which includes four corners


314


. In the illustrated embodiment, the corners


314


are radiused to reduce the wear on the disc


110


during use. The radiused corners may also be textured with a variety of patterns. This texturing may assist in the or movement of materials with the disc


110


. In the illustrative embodiment shown, the corners


314


are textured with a plurality of ridges


316


. The outer peripheral edge of the disc


110


defines an annular impacting surface


330


. Also shown in the figures is a cylindrical shoulder


362


or boss integrally formed on and protruding from each side of the disc. The shoulder


362


allows for room between the impacting surfaces


330


of adjacent discs


110


when they are positioned in a fine mesh pattern. Further, the shoulders


362


of adjacent discs provide a lateral space within which the peripheral edge of an interleaved disc on an adjacent shaft may be received to create a small space such as the space


204


for fine material screening. (See

FIG. 2A.

)




For the disc


110


to function well, it must have a flexible impacting surface


330


with high abrasion resistance for impacting the materials, while at the same time having a “sticky” surface with a high coefficient of friction. There are a number of materials, such as rubber, that may be used in making the disc


110


. A coating of material may also be applied to the impacting surface


330


.




With reference to

FIGS. 3A

,


4


A,


4


B,


5


A and


5


B, it should appreciated that the disc


110


comprises two identical halves, placed in opposition on a shaft and clamped thereto. Each half is referred to as a “portion”. In

FIG. 3A

, the disc


110


includes identical opposing portions


302




a


and


302




b


. As best seen in

FIGS. 4A-4C

, a disc portion


302


(representing both of portions


302




a


and


302




b


) has an internal rigid frame or embedment


318


to which a rubber material


326


is molded. (Note, for accuracy, that portion


302


corresponds to portion


302




a


, with its top and bottom ends rotated 180°). Preferably, the rubber material is a 50-55 durometer rubber casting compression molded around the rigid frame


318


. The rigid frame


318


imparts stiffness to the disc portion


302


and improves the clamping force


312


when two disc portions


302




a


and


302




b


are clamped to a shaft. As shown in FIG. SA and


5


B, the rigid frame


318


includes a first unthreaded through hole


320


and a second, threaded hole


322


. Each of the holes


320


and


322


opens through a respective exposed clamping face


325


on a respective end of the rigid frame


318


. As best seen in

FIG. 4A

, a through hole


327


opens through the rubber material


326


from impacting surface


330


to the through hole


320


. Referring back to

FIG. 3A

, it can be seen that the disc


110


may be clamped to a shaft by bringing the two disc portions


302




a


and


302




b


together about the shaft such that the through hole


320


in the portion


302




a


faces the threaded portion


322


in the portion


302




b


, and the through hole


320


in the portion


302




b


faces the threaded portion


322


in the disc portion


302




a


. The two portions


302




a


and


302




b


are clamped by threaded screws


304


that are inserted through the through holes


327


,


320


, threaded ends first, and then threaded to the respective threaded holes


322


in the opposing disc portions. This securely clamps the disc


110


to a shaft.




Secure clamping is provided, in this regard, by the exposed opposing clamping faces


325


, over which the rubber material


326


does not extend. Thus, where the clamping force is applied, the clamping faces


325


of the rigid frames


318


within the opposing disc portions


302




a


and


302




b


are brought together in contact to provide a stiff, nonyielding clamping interface. In addition, the planar sections


310


, which are part of the rubber material


326


, are squeezed between the metal shaft and corresponding portions


310




a


of the rigid member


318


. This compresses these planar sections


310


to such an extent that the disc


110


is firmly clamped to, and cannot slide along a shaft. Now, if the disc


110


is damaged and must be repaired or replaced, it can be dissembled from the shaft by dethreading the screws


304


, removing the portions


302




a


and


302




b


and replacing either or both.




Two significant advantages of the disc configuration illustrated in

FIG. 3A

are evident. First, the clamping force exerted by the screws


304


is not parallel to any of the planar sections


310


of the inner opening of the disc


110


and therefore is not parallel to any of the surface portions of the shaft


108


or


112


. In other words, there is a component of a clamping force vector that is normal to the interface between each of the clamping planar sections


310


and the shaft


108


or


112


. This advantageously distributes the clamping force around the interface between the inner opening of the disc


110


and the shaft


108


or


112


. Second, the plane


306


where the disc portions


302




a


and


302




b


are brought together defines a minute seam that extends to respective opposing flat portions of the impacting surface


330


. This is best seen in

FIGS. 3A and 3C

. Since the impacting surface


330


tends to contact the material stream at the corners


314


, filaments, such as strings or threads are less likely to snag in the seams than if they were located at the corners of the disc


10


.




The rigid frame


318


, shown in

FIG. 5A-5C

, may be made of metal, such as steel or aluminum, or a rigid plastic. In the preferred embodiment, the rigid frame is made from


356


aluminum casting that has been heat treated.





FIGS. 7A-7C

and


8


A-


8


B show construction of details of the rotatable shafts


108


,


112


which are represented by a shaft assembly


400


. The shaft assembly


400


consists of a central axle tube


402


and two end spindle assemblies


404


, each disposed partially in the tube


402


, near an end. In the illustrative embodiment, the axle tube


402


has a square cross-section to which the disc


110


is clamped (see FIG.


3


A). The center of the axle tube


402


is generally hollow. Each spindle assembly


404


is constructed to mount within a respective end of the axle tube


402


. The spindle assembly


404


is comprises a central spindle


406


and attachment discs


408


. One end of the central spindle


406


is dimensioned to fit inside an end of the axle tube


402


while the exposed end of the spindle


406


is dimensioned to attach to a disc screen apparatus. In the present invention, the exposed spindle ends are sized to be compatible with the rotation bearings


140


, drive sprockets


142


and rotation sprockets


144


of the apparatus


100


. The attachment discs


408


are initially dimensioned to be larger than the central opening


410


of the axle tube


402


. In the configuration shown in

FIG. 7 and 8

, the attachment disc


408


is circular in shape with a circular center opening that is sized to fit over the spindle


406


. One or more attachment discs


408


are welded to the spindle


406


to form the spindle assembly


404


. The spindle assembly


404


is then positioned in a fixture where the attachment discs


408


are machined to press fit into the central opening


410


. Once sized, the spindle assembly


404


is press fit into the opening


410


a set distance. The attachment discs


408


are used to center and align the spindle


406


along the axis


414


of the shaft. A plurality of holes


412


in the axle tube


402


are used to weld the attachment discs


408


in place, thus securing the spindle assembly


404


in the axle tube


402


, forming the axle assembly


400


. The axle tubes


402


, spindles


406


and attachment discs


408


are preferably made from high strength materials, such as steel.




While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims. For example, the discs may have shapes other than the square one shown, and may have central openings that have eccentric shapes including curved ones such as ellipses and regular ones such as triangles, quadrilaterals, and polygons.



Claims
  • 1. A disc for attachment to a shaft in a disc screen apparatus comprising:an inner rigid frame; an outer material partially covering the rigid frame; and wherein the disc has an outer perimeter which is substantially square with radiused corners.
  • 2. The disc of claim 1 further comprising;a cylindrical boss extending from at least one side of the disc, the boss having a thickness and an outer perimeter.
  • 3. The disc of claim 2 wherein an outer perimeter impact surface of the disc is greater than the outer perimeter of the boss.
  • 4. The disc of claim 1 wherein the radiused corners have a texture.
  • 5. The disc of claim 1 wherein the disc includes a first portion and a second portion configured to be coupled together around a shaft.
  • 6. The disc of claim 5 wherein the disc further comprises;a disc parting plane separating the disc into a first portion and second portion, each portion containing a fraction of the rigid frame such that when the first and second portions are joined, a joining surface of the fraction of the rigid frame in the first half contacts a joining surface of the fraction of the rigid frame in the second half.
  • 7. The disc of claim 1 wherein the outer material is compression molded around the rigid frame.
  • 8. The disc of claim 1 wherein the outer material includes rubber.
  • 9. The disc of claim 1 wherein the rigid frame is made of metal.
  • 10. A disc for releasable attachment to a shaft in a disc screen apparatus for classifying mixed recyclable materials, comprising:an inner rigid frame; a flexible material covering the rigid frame, the flexible material having high abrasion resistance for impacting recyclable materials to be classified and having a high co-efficient of friction for engaging and propelling the materials in a conveying direction along a disc screen; the inner rigid frame and the outer material covering the frame being separable into a plurality of portions, the portions of the inner rigid frame being configured to provide an opening for receiving a shaft of the disc screen apparatus; means for releasably clamping the inner rigid portions around the shaft; and wherein the portions made of flexible material define an outer impacting surface with a generally square shape including rounded corners connected by flat portions.
  • 11. The disc of claim 10 wherein the portions made of flexible material have a seam that extends to opposing flat portions of the impacting surface.
  • 12. The disc of claim 10 wherein the shaft receiving opening is square and the clamping means includes a pair of bolts that extend on either side of the shaft parallel to a diagonal of the square shaft.
  • 13. The disc of claim 10 wherein the inner rigid frame is made of metal and the flexible material is a rubber material molded to the inner rigid frame.
  • 14. A disc for releasable attachment to a shaft in a disc screen apparatus for classifying mixed recyclable materials, comprising:an inner rigid frame; an outer material partially covering the rigid frame and defining an outer impacting surface with a generally square shape for engaging and propelling mixed recyclable materials in a conveying direction along a disc screen; the inner rigid frame and the outer material covering the frame being separable into a plurality of portions, the portions being configured to provide an opening for receiving a shaft of the disc screen apparatus; and means for releasably clamping the portions around the shaft.
  • 15. A disc for releasable attachment to a shaft in a disc screen apparatus for classifying recyclable materials, comprising:a flexible material defining an outer impacting surface shaped for engaging and propelling mixed recyclable materials in a conveying direction along a disc screen apparatus; a rigid frame embedded within the flexible material and extending a substantial radial distance within the flexible material to impart stiffness; the flexible material and the inner frame being separable into a plurality of portions that can be assembled around a shaft of the disc screen apparatus; and means for releasably clamping the portions around the shaft.
Parent Case Info

This application is a division of U.S. patent application Ser. No. 09/246,999 filed Feb. 8, 1999, and patented on Jun. 26, 2001 as U.S. Pat. No. 6,250,478 B1.

US Referenced Citations (26)
Number Name Date Kind
1621695 Tuite et al. Mar 1927
1641777 Newhouse Sep 1927
1679593 Williamson et al. Aug 1928
1699718 Robins Jan 1929
2266506 Morse Dec 1941
2588309 Troyer Mar 1952
2860766 Welter Nov 1958
2949189 Haines Aug 1960
2983376 Troyer May 1961
3306441 Sanders et al. Feb 1967
3519129 Peterson Jul 1970
3642520 Lazzarini Feb 1972
4402390 Feeney Sep 1983
4724950 Okamura Feb 1988
4795036 Williams Jan 1989
5035314 Kornylack Jul 1991
5279427 Mobley Jan 1994
5352469 Peters Oct 1994
5450966 Clark et al. Sep 1995
5697704 Coyle Dec 1997
5868036 Salzman Feb 1999
5931312 Gifford Aug 1999
5960964 Austin et al. Oct 1999
6076684 Bollegraaf Jun 2000
6149018 Austin et al. Nov 2000
6234322 Paladin May 2001
Foreign Referenced Citations (1)
Number Date Country
2054615 Jan 1999 CA