CA1249985A

CA1249985A - Size reduction granulator

Info

Publication number: CA1249985A
Application number: CA000467794A
Authority: CA
Inventors: Reginald G. Roberts
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-11-14
Filing date: 1984-11-14
Publication date: 1989-02-14

Abstract

ABSTRACT OF THE DISCLOSURE
- The present invention provides a device for size reduction of various different recyclable materials. The device comprises a cutter assembly consisting of a motor operated rotatable portion and a fixed portion both of which have stepped edge regions between which the material is cut.

Description

1 .
FIFLD OF TH~ INVENTION
_ _ The present invention relates to a device for size reduction of recyclable ma-terial and includes a granulating assembly having a rotatable body and a fixed body between which the material is passed for the size reduction.
BACKGROUND OF THE INVENTION

-In view of ever-rising rnaterial costs there has been a substantially increased tendency to construct articles from recyclable materials. Such articles can be made from different recyclable materials such as plastics, aluminum, etc~
Accordingly, there is a need for a device capable of reducing recyclable materials to a small particle size suitable for recycling.
There are also other applications outside of the recycling industry in which materials must be reduced to an extremely small particle size. For instance, sizing devices are required in the wood working industry which must be capable of reducing large pieces of wood to an extremely small wood chip size.
SUMMARY OF THE PRESENT INVENTIO_ The present invention provides a high capacity material granulating device for the granulating of different desired materials. The device comprises a crusher assembly wlth feed means for feeding the material to the crusher assembly. The crusher assembly itself consis-ts of a motor-operated rotatable portion having at least one tooth 8~

bearing edge region and a stationary portion, having a fixed edge region past which the tooth-bearing edge region rotates.
The tooth-bearing edge region comprises a plurality of radially extending teeth, which are stepped to provide a alternating long and short tooth pattern and the fixed edge region is reversely stepped to mate with the tooth-bearing edge region for granulating or size reduction of the material therebetween.
This stepping arrangement at the two mating edge regions provides an enlarged contact surface in comparison to a standard flat edge region contact. Accordingly the device of the present invention is specifically adapted to provide extremely efficient granulating of different types of materials to a small particle size for different purposes such as the recycling of the material.
BRIEF DISCUSSION OF THE DRAWINGS
The above, as well as other advantages and features of the present invention will be described in greater detail according to the preferred embodiments of the present invention in which:
Figure 1 is a perspective view of a crusher device, according to a preferred embodiment of the present invention.
Figure 2 is a sectional view of the granulating device of Figure 1.
Figure 3 is an enlarged sectional view through the granulating region of the device of Figures 1 and 2;
Figure 4 is a perspective view of a granulating grid ~2~38';

assembly used in an alternate embodiment to that shown in Figure 3.
Figures 5 is an exploded perspective view of the rotatable and fixed portions of the granulating assembly from the device of Figure l;
Figure 6 is an enlarged exploded perspective view of a tooth and its mounting arm of the rotatable portion of the granulating assembly from Figure 5;
Figure 6a is a perspective view of a cutting bar bed region according to a further preferred embodiment of the present invention.
Figure 7 is a top plan view showing the interaction between the rotatable and fixed portions of the granulating assembly of Figure 5;
Figures 8 and 9 are sectional views through the rotatable portion of a granulating assembly according to a further preferred embodiment of the present invention.
DETAILED DESCRIPTION ACCORDING Tû THE PREFERRED EMBODIMENTS OF
THE PRESENT INVENTIûN
A granulating device is generally indicated at 1, in Figures 1 and 2. This device includes a feed chute 3, which feeds material to be granulated within the device to an internal granulating assembly generally indicated at 6.
Provided within the feed chute are a plurality of curtains 5A, 5B and 5C. These curtains are pushed aside to insert the material down the chute and to prevent the material from flying ~3C3~5 back through the chute while the device is in operation. The device can be used for size reduction of many different types of materials including recyclable materials and the device as shown has particular application for the granulating of recyclable plastic material.
One of the main features of the present invention is the high capacity granulating action of the device. This is achieved by providing a stepped tooth arrangement at the edges of the mating parts of the granulating assembly which consists of a rotatable portion generally indicated at 7 and a fixed portion generally indicated at 21 in Figure 5.
The rotatable portion of the assembly is, in the embodiment shown, provided with three separate and distinct granulating or in this case cutting edge regions which are circumferentially spaced from one another around the rotatable portion of the assembly. Each one of these longitudinally extending edge regions has a series of alternatingly stepped teeth to provide the high capacity granulating action which will be described later in greater detail.
According to the embodiment shown in Figure 2, the rotatable portion of the assembly is made up from a plurality of independent first and second tooth bearing members shown at 10 and 15 respectively. Each first tooth-bearing member 10 is of increased diameter relative to each second tooth-bearing member 15, with the first and second tooth-bearing members being alternately mounted, side by side with one another, along ~2~ S

a common shaft 17 and rotatably coupled to the shaft by means of key portions 19 providing independent journalling of each tooth bearing member to the shaft. Each of the first and second tooth-bearing members comprises a generally disc-like body portion having three radially extending arms with the radial arms 11 of the first tooth bearing members extending outwardly beyond similarly shaped, but shorter, radial arms 16 on the second tooth-bearing members. Each of these radial arms on both the first and second tooth-bearing members is provided with a cutting tooth 13, mounted to the forward face of each arm. As best shown in Figure 6, each tooth is removably secured in position by means of a nut and bolt arrangement 12 in a readily accessible position on the arm. This arrangernent allows easy removal and replacement of the teeth for purposes of sharpening or replacing of broken teeth.
As also seen in Figure 6, tooth 13 is provided with a pair of slightly radiused cutting edges 14 one to either side of the tooth. The radiusing or curving of the cutting edge substantially enhances its cutting action and the provision of cutting edges to either side of the tooth allows the tooth once one of the cutting edges has been dulled to be reversed in position for exposing the other sharper cutting edge. After both cutting edges have been used the tooth can then be removed for resharpening of both cutting edges.

~2~ 8~i Although the drawings specifically show the use of 3 cutting teeth on each disk-like tooth bearing member, it is to be appreciated that this arrangement can be easily varied. For example in a lower capacity granualting machine each of the tooth bearing members may be provided with one or two teeth1 as opposed to the three teeth shown in the drawings. On the o-ther hand, for larger machines a greater number of teeth such as 5 or 6 may equally as well be provided on each tooth bearing member appropriately spaced therearound. Furthermore, in larger machines there may be applications in which each tooth is secured to the arm of the tooth bearing member by a plurality of securing nuts and bolts.
As best seen ir Figure 2, the entire rotatable portion of the granulating assembly is driven through a belt B by a motor M within the device. As seen in Figure 1, the outside of the device is provided with acoustic panels 30 to maintain the noise created by the device while in operation at an acceptable noise level.
The fixed portion 21 of the granulating assembly is made from alternating short and long bed knives 23 and 24 to provide a fixed edge region, having a reverse step to that found on the rotatable portion of the assembly. Accordingly, the two portions are adapted to mate with one another for purposes of granulating the material at the interface of the two edge regions.
Bed knives 23 and 24 are adjustable in position to 1;;~ L~ 8 S

ensure a proper clearance between the bed knives and the rotating teeth in the assembly. As seen in Figure 5, bolts 25 are provided to the rear of each of the bed knives enabling them to be threadably advanced with extreme accuracy toward or withdrawn from the rotating teeth. Once in a properly adjusted position the bed knives are then tightened down by means of bolts 26, fitted in elongated slots which enable shifting of the bed knives as again seen in Figure 5.
Figure 6A shows a modification to the fixed edge region of the granualting assembly. According to this modification the fixed edge region comprises a one plece knife bed 20 for receiving a plurality of tooth like bed knives 22.
Each of these bed knives comprises alternating short and long tooth portions 23A and 24A removably secured to the one piece knife bed by means of bolt 26Ao Consistent with the teeth on the rotatable por-tion of the granualting assembly, the bed knives 22 are reversible in position due to the provision of tooth surfaces to either side of each knife as well as shown in Figure 6A. It should be noted that the knife bed is formed with a toothed edge pattern to allow the flipping or reversing of each of the teeth.
Furthermore, this toothed edge region is cut at a slight angle O to accommodate the shaping of each of the teeth surfaces on the knives 22.

C38~
. 8 .
This particular bed knife arrangement has a number of desirable features. Firstly, each knife can be reversed in position once the exposed cutting edge has been dulled after extended use. Secondly, only the bed knives themselves need be constructed of relatively expensive material such as hardened tool steel while the support bed itself may be constructed from a much less expenslve carbon steel or -the like. Finally there is no need for individual adjustment of the bed knives due to the provision of a common supporting bed secured in position by bolt 28 with a single adjustment mechanism for that supporting bed common to all of the bed knives.
The interaction between the rotating and the fixed edge region is best seen in Figure 7 which shows in plan the rotating of the edge region on the rotating portion past the edge region of the fixed portion of the granulating assembly.
Here it will be seen that there are three mating surface regions between the two stepped edges including regions A and B
at the extreme outer edges of the teeth and bed knives as well as mating surface regions C, along the side faces of the oppositely stepped edge regions. It is this additional interface region C that provides the substantially increased capacity over a flat edged granulator. It also provides a cooling feature in that there is an undulating path for -the flow of cooling air along the stepped teeth in the granulating assembly.

~ 9~

A further feature ot` the present invention which is best seen in both Figures 1 and 5 of the drawings is that the individual tooth bearing members 10 and 15 are mounted so as to form a helical cutting edge around the rotatable portion of the granulating assembly. In fact, the two sets of tooth bearing members are set up to provide a double helix on the rotating member. This double helix is achieved by offsetting each of the first tooth bearing members 10 at a consistent angle relative to one another, e.g. 10 degrees, and by offsetting each of the second tooth bearing members 15 at a different angle relative to one another, e.g. 9 degrees. In reference to Figure 5 it will be seen that the first tooth bearing member 10 to the left hand side of the figure is advanced in its rotating position relative to the tooth bearing member 10 to the left hand side of the figure. The middle second tooth bearing member 15 is positioned on shaft 17 such that each of the teeth on this second tooth bearing member is retarded in its rotational position relative to the first tooth bearing member on the left hand side of the figure while being advanced in rotation relative to the first tooth bearing member on the right hand side of the figure.
The operation of the device is best seen in Figure 3 which shows a piece of scrap material 9, dropping down to the granulating assembly of the device. This piece of scrap material, after being granulated is reduced to small pieces 9A, which are of a size particularly suitable for recycling C~i~85 . 10 .
purposes. Located below the granulating assembly is a screen 27 which acts as a filter to allow appropriately sized pieces of the recyclable material to drop down into a collector box 29. The pieces that are not adequately sized will not pass properly through screen 27 and as such, get caught up for further granulating within the assembly until they are reduced to the appropriate particle size. It will be seen in Figure 3 that there are two sets of bed knives at the front and the back of the granulating region to cooperate with the cutting knives on the rotatable portion of the assembly thus, further increasing the granulating capacity of the device.
Figure 4 shows a grid arrangement 45 formed of first ribs 47 which extend in the direction of rotation of the rotatable granulating member and second ribs 49 transverse of the first ribs 47. As will be seen in Figure 4 the second ribs 49 are slightly taller than the first ribs 47 and have knife-like upper edges which cooperate with the cutting teeth in the rotatable portion of the granulating assembly for further increasing the cutting or shredding action of the granulator.
As mentioned above, the device includes a collector box 29 for collecting the small particles of recyclable sized material. As shown in Figure 1, this collector box is easily removed from the crusher for gathering of the small particles.
However, in lieu of the collector box the device can also be set up with a collector region having a discharge chute and a ~2~ 5 11 .
blower for blowing the particles from the collector region through the discharge chute to a desired collecting area.
One very important aspect of the present invention is the reduction of potential jamming pressures or forces on the granulating assembly. This aspect is achieved through the following features:
Firstly, the teeth on each of the first and second tooth-bearing members have the radius shaping described above so that the forward cutting face of each tooth is angled to cut into the material which is being granulated so as to reduce pressure on each tooth.
Secondly, all of the first and second tooth-bearing members are mounted, on shaft 17, in a manner such that the circumferentially spaced stepped cutting edges around the rotatable portion of the assembly each extends longitudinally of the rotatable portion in a gradual helical path as described above. Accordingly, there is a graduated movement of each cutting edge the rotatable portion past the fixed portion of the granulating assembly which substantially reduces pressure on the overall assembly.
A third feature which reduces the likelihood of jamming, is the independent mounting of each of the tooth-bearing members on shaft 17 so that any one of the tooth-bearing members can be broken away from the shaft without `` 12~985 . 12 affecting the remaining members.
A further preferred embodiment arrangement for achieving this independent mounting of the tooth-bearing members is shown in Figures 8 and 9 of the drawings. In Figure 8 a tooth-bearing member 31 is rotationally coupled to a rotating shaft 39 by means of a shear pin 33. This tooth-bearing member has a threaded opening for threadably securing the shear pin in position and the shaft has an aperture which aligns with the threaded opening in the tooth-bearing member for receiving the shear pin tip 34 so that tooth bearing member 31 rotates with shaft 39.
Shear pin 33 has an internal cavity 35 containing a lubricant 37, which, when the shear pin is intact, remains within the cavity; however, in the event that this shear pin is broken, as shown in Figure 9 where the tooth-bearing member is jammed, the tip of the shear pin breaks away, allowing shaft 39 and any other tooth-bearing members mounted on the shaft to continue to rotate. The breaking away of the shear pin tip exposes the internal cavity 35 within the shear pin directly to the surface of the shaft and allows the spreading of tl-e lubricant from the cavity directly onto the shaft surface. For purposes of enhancing the spreading of the lubricant, a recess region 41 is provided on the shaft surface around the shear pin receiving aperture into which shear pin tip 34 is fitted. This recess region collects lubricant from the internal cavity of the shear pin and spreads the lubricant as it rotates within ~2~85 . 13 the jammed body 31, causing the lubricant to be spread entirely around the contacting surfaces of the shaft and the inner shaft mounting surface of the jammed body.
It is to be appreciated that this particular mounting system need not be restricted to the granulating device of the present invention and could, in fact, be used with any type of device in which a body is rotatably coupled to a shaft where that body is subject to jamming pressures. Regardless of the application, the lubricant spread around the shaft prevents damage caused by scoring of the shaft which would otherwise be caused by rotation bctween a dry shaft surface and a jammed body.
For an arrangement as described used for the size reduction of plastics material, a non-melt molygrease provides a particularly suitable lubricant. Such a grease does not tend to break down under high temperatures and tends to have little flow outside of the particular region in which it is spread.
Accordingly, the non-melt molygrease will have little tendency to run along the shaft and flow into the plastic material and therefore substantially eliminates grease discolouration of the plastic.
In a further embodiment of the invention the grease trapping and spreading recess is provided in the body itself rather than at the surface of the shaft. This feature is again particularly useful in the granulating of plastic material since it also effctively prevents spreading of the grease to ~, 2 L~ t 8 ~
. 14 the plastic material.
Although various preferred embodiments of the invention have been described herein in detail, it will be appreciated by those skilled in the art that variations may by made thereto without departing from the spirit of the invention or the scope of the appended claims.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A material granulating device comprising a granulating assembly and feed means for feeding the material to said granulating assembly, said granulating assembly consisting of a motor operated rotatable portion having at least one tooth-bearing edge region and a stationary portion having a fixed edge region past which said tooth-bearing edge region rotates, said tooth-bearing edge region comprising a plurality of radially extending teeth which are stepped to provide an alternating long and short tooth pattern at said tooth bearing edge region said fixed edge region being reversely stepped to mate with said tooth bearing edge region for granulating of the material therebetween.

2. A device as claimed in Claim 1 wherein each said tooth bearing edge region extends in a gradual helical path longitudinally of said rotatable portion of said granulating assembly.

3. A device as claimed in Claim 1 including a plurality of said tooth-bearing edge regions on said rotatable portion, each tooth-bearing edge region on said rotatable portion being extended in a gradual helical path longitudinally of said rotatable portion of said granulating assembly.

4. A device as claimed in Claim 1 wherein each tooth of said plurality of radially extending teeth on said tooth-bearing edge region of said rotatable portion has a radiused tooth edge.

5. A device as claimed in Claim 4 wherein each tooth is provided with a pair of radiused tooth edges, one to either side thereof, and is removable and reversible in position at said tooth bearing edge region.

6. A device as claimed in Claim 1 wherein said rotatable portion of said granulating assembly consists of a plurality of first and second tooth-bearing members mounted on a common shaft for rotation thereof, said first members being of increased diameter relative to said second members and said first and second members being positioned side by side along said shaft to form said alternating long and short tooth pattern.

7. A device as claimed in Claim 6 wherein said first and second tooth-bearing members are all mounted independently of one another on said shaft for reducing jamming pressures on said device.

8. A device as claimed in 6 wherein each of said first and second tooth-bearing members includes a plurality of teeth spaced circumferentially from one another around each tooth bearing member to form a plurality of said tooth-bearing edge regions around said rotatable portion of said granulating assembly.

9. A device as claimed in Claim 8 wherein each of said tooth-bearing edge regions extends in a gradual helical path along said rotatable portion of said granulating assembly.

10. A device as claimed in Claim 8 wherein said teeth are removably secured in position for replacement and sharpening thereof.

11. A device as claimed in Claim 7 including shear pins for mounting said first and second tooth bearing members on said shaft, said shear pins allowing independent shearing of each member relative to said shaft.

12. A device as claimed in Claim 11 wherein each shear pin is provided with a lubricant stored internally thereof and spreadable onto said shaft in the event of shearing.

13. A device as claimed in Claim 12 wherein said lubricant comprises a non-melt molygrease.

14. A device as claimed in Claim 12 wherein said shaft is provided with a plurality of apertures for receiving the shear pins for rotatably coupling said first and second tooth bearing members on said shaft, and a recessed region in one of said shaft and said first and second tooth bearing members for enhancing spreading of the lubricant onto said shaft.

15. A device as claimed in Claim 11 wherein said first and second tooth-bearing members are provided with threaded openings for threadably receiving said shear pins which are threaded for securing in said openings enabling easy shear pin removal and replacement.

16. A device as claimed in Claim 10 wherein each first and second tooth-bearing member comprises a disc-like body having a plurality of generally radially extending arms, each of said teeth being removably secured to each arm by a nut and bolt securing arrangement in a readily accessible position.

17. A device as claimed in Claim 1 wherein said feed means comprises a loading chute provided with at least one moveable curtain enabling insertion while preventing spray-out of the material from the device.

18. A device as claimed in Claim 1 including a filtering means beneath said granulating assembly and collecting means for collecting material granulated by said granulating assembly and filtered through said filtering means.

19. A device as claimed in claim 18 wherein said filtering means comprises a sizing screen.

20. A device as claimed in Claim 18 wherein said filtering means comprises a grid having a knife edge upper surface for cooperating in the granulating of the material.

21. A device as claimed in Claim 18 wherein said collecting means comprises a collector box removably positioned in said device.

22. A device as claimed in Claim 1 wherein said stationary portion of said fixed edge region comprises a plurality of bed knives adjustable in position for setting tolerances relative to the teeth in said tooth bearing edge region.

23. A device as claimed in Claim 22 including a threaded adjustment system for adjusting position of said bed knives.

24. A device as claimed in Claim 22 wherein each of said bed knives presents a long and a short knife surface to either side thereof for mating with said tooth bearing edge region and said bed knives being reversible in position on a supporting bed common to all of said bed knives.