Patent Application
20210346893
The invention generally relates to an improved replaceable tooth for a material fragmenting machine or a comminuting machine.
Fragmenting or comminuting machines are designed to splinter and fragment materials using tremendous impacting forces. There are several types of comminuting machines. Some machines are gravity fed. They have chutes that are tilted toward a rotationally powered fragmentation device. Gravity is used, in whole or in part, to move materials into fragmentation device. Other comminuting machines have substantially horizontal beds. The material is fed to the fragmentation device using a conveyor belt or other means of advancing the material to the fragmentation device.
The fragmentation device includes a rotationally powered drum that includes teeth that grind or pulverize the incoming material. The rotationally powered drum is commonly known as a rotor or hammer mill, with peripherally mounted comminuting instruments, commonly referred to as teeth, hammers, cutters, and other names suggestive of their function, extending from the drum. These teeth revolve about an axis generally perpendicular to the flow of feed materials at speeds typically exceeding 1000 rpm's, though lower speeds are also found on such devices. When an object enters the radial path of a rotor tooth, it is carried into a plate or bar that is fixed in place and generally labeled an anvil. After the initial striking of the feed material by a rotor tooth, the anvil, located a short distance beyond the outer circumferential path of the teeth, facilitates a second stage of the fragmentation process, as the feed material is subjected to great shearing and pulverizing forces between the radially traveling tooth and the anvil. After the material passes beyond the anvil, it circulates between the teeth and a sizing screen, an apparatus concentrically surrounding a portion of the rotor with apertures roughly the size of the desired finished product. Frangible objects continue to be broken down between the teeth and screening apparatus until they are small enough to pass through these apertures.
Feedstock may encounter the rotor teeth several times before passing through a sizing aperture as a result of repeated ejection up into the feed opening and subsequent descent into the comminuting zone. Each encounter with the comminuting zone may result in the feedstock fragmenting into smaller pieces. In these situations, machine operators may not experience effective control over particle size and texture. Repeated and excessive contact between the rotor teeth and individual pieces of feed material also reduces production efficiency and increases component wear in proportion to output.
Wear on the rotor teeth is a concern that results in reductions in fragmenting efficiency and increases in costs related to maintenance and service to replace worn rotor teeth and tooth mounts. Known waste fragmenting machines may require heavy solid steel shafts and/or lock collars to hold tooth mounts and mounted teeth in position on the rotor. Such waste fragmenting machines require disassembly to replace the worn tooth mounts which is particularly labor intensive and costly.
The teeth impart massive impact loads. Teeth may become chipped, warped, or gouged, resulting in rotor imbalance and/or inability to properly secure teeth.
As a result, there remains a need for an improved tooth that has improved wear. A longer wearing tooth or set of teeth does not have to be replaced as often which saves maintenance costs while maintaining efficiencies for a longer period of time.
Embodiments of the invention may be best understood by referring to the following description and accompanying drawings, which illustrate such embodiments.
In the drawings:
The following detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments, which are also referred to herein as “examples,” are described in enough detail to enable those skilled in the art to practice the invention. The embodiments may be combined, other embodiments may be utilized, or structural, and logical changes may be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents.
Before the present invention is described in such detail, however, it is to be understood that this invention is not limited to particular variations set forth and may, of course, vary. Various changes may be made to the invention described and equivalents may be substituted without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process act(s) or step(s), to the objective(s), spirit or scope of the present invention. All such modifications are intended to be within the scope of the claims made herein.
Methods recited herein may be carried out in any order of the recited events which is logically possible, as well as the recited order of events. Furthermore, where a range of values is provided, it is understood that every intervening value, between the upper and lower limit of that range and any other stated or intervening value in that stated range is encompassed within the invention. Also, it is contemplated that any optional feature of the inventive variations described may be set forth and claimed independently, or in combination with any one or more of the features described herein.
The referenced items are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such material by virtue of prior invention.
Unless otherwise indicated, the words and phrases presented in this document have their ordinary meanings to one of skill in the art. Such ordinary meanings can be obtained by reference to their use in the art and by reference to general and scientific dictionaries, for example, Webster's Third New International Dictionary, Merriam-Webster Inc., Springfield, M A, 1993 and The American Heritage Dictionary of the English Language, Houghton Mifflin, Boston Mass., 1981.
In basic operational use in various embodiments, waste materials W may be power fed by a conveyer system to a fragmenting or grinding chamber 14 by a powered feed system 16 powered by a feed motor MF in cooperative association with a power feed rotor drum 16D powered by power feed motor MP.
Thus, one embodiment of the machine 10 may include a hopper 18 for receiving waste materials W and a continuously moving infeed conveyer 20 for feeding wastes W to the waste fragmenting or grinding chamber 14. An infeed conveyer 20 may be suitably constructed of rigid apron sections hinged together and continuously driven about drive pulley 20D and an idler pulley 20E disposed at an opposing end of the conveyer 20. The conveyer 20 may be operated at an apron speed of about 10 to about 30 feet per minute, depending upon the type of waste material W. The travel rate or speed of infeed conveyer 20 may be appropriately regulated through control of gearbox 20G. Feed motor MF in cooperative association with gear box 20G, apron drive pulley 20P, chain 20F, and apron drive sprocket 20D driven about feed shaft 20S serves to drive continuous infeed conveyer 20 about feed drive pulley 20D and idler pulley 20E.
Power feed system 16 is driven by motor MP and in cooperative association with the infeed conveyer 20, driven by motor MF, uniformly feeds and distributes bulk materials, W, such as cellulose-based materials to the fragmenting or grinding chamber 14. Power feed system 16 positions and aligns the materials W for effective fragmentation by the fragmenting rotor 40. The power feed system 16 comprises, in one embodiment and as illustrated, a power feed wheel or rotor drum 16D equipped with projecting feeding teeth 16A positioned for counterclockwise rotational movement about power feed wheel 16D. Power feed wheel 16D may be driven by power feed shaft 16S which in turn is driven by chain 16B, drive sprocket 16P and motor MP. The illustrated embodiment further comprises arm 16F which holds power feed wheel 16D in position.
A rotary motor MR serves as a power source for powering a fragmenting rotor 40 that operates within the fragmenting or grinding chamber 14. The fragmenting and grinding are accomplished, in part, by shearing or breaking teeth 500 which rotate about a cylindrical drum 42 and exert a downwardly and radially outward, pulling and shearing action upon the waste material, W, as it is fed onto a striking bar 43 and sheared thereupon by the teeth 500. Within some machines, the rotor may rotate upward into the feed material. The shearing teeth 500 project generally outwardly from the cylindrical drum 42, which is typically rotated at an operational speed of about 1800-2500 r.p.m, though, as discussed above, other r.p.m. ranges are well within the scope of the present invention. The fragmenting rotor 40 is driven about a power shaft 42S, which is in turn powered by a suitable power source such as motor MR. Motor MR is drivingly connected to power shaft pulley 42P which drivingly rotates power shaft 42S within power shaft bearing 42B. The rotating teeth 500 thus create a turbulent flow of the fragmenting wastes W within the fragmenting chamber 14.
Initial fragmentation of the material, W is, in one embodiment, accomplished within the dynamics of a fragmenting or grinding chamber 14 which may comprise a striking bar 43 and a cylindrical drum 42 equipped with a dynamically balanced arrangement of the shearing or breaker teeth 500. The striking bar 43 serves as a supportive anvil for shearing material W fed to the fragmenting zone 4. Teeth 500 are staggered upon cylindrical drum 42 to facilitate dynamic balancing of rotor 40. Rotor 40, generally operated at an operational rotational speed of about 1800-2500 r.p.m., rotates about shaft 42S. Material fragmented by the impacting teeth 500 is then radially propelled along the curvature of the screen 44. Screen 44, in cooperation with the impacting teeth 500, serves to refine the material W into a desired particle size until ultimately fragmented to a sufficient particle size so as to pass through screen 44 for collection and discharge by discharging conveyor 50. A discharging motor MD serves as a power source for powering a discharger 52, illustrated as a conveyor belt and pulley system, wherein the discharger 52 conveys processed products D from the machine 10.
The power feed system 16 helps to maintain a substantially consistent feed rate to the fragmenting chamber and rotor therein. Stabilization of the feed material prior to entry into the fragmenting chamber is essential to fragmentation speed and efficiency. The need for feed stability in a fragmenting machine is relative to the size and consistency of the feed material, as well as the rotor r.p.m. and torque. Thus, the power feed system 16, also referred to as a pre-crusher, power feeder, power feed drum, power feed roll or roller, or powerfeed, is an integral component of an efficient horizontal grinder.
A typical power feed wheel 16D usually comprises serrated plates, cleats or other elements, represented in
Maintenance of a certain downward pressure of the power feed wheel 16D on the feed material will help regulate the speed with which the material enters the fragmenting chamber and encounters the rotor. This downward pressure assists, inter alia, in preventing the fragmenting rotor 40 from pulling the feed material in too quickly. The downward pressure of the power feed wheel 16D stabilizes the feed material by providing a level of compression and lateral movement of the feed material prior to encountering the rotor, thus improving the efficacy of fragmentation within the fragmenting chamber 14. power feed device described is not a required element.
Cylindrical drum 42 has an outer surface S with a plurality of spaced apart cutouts 102. Within each cutout 102, a holder 110 is attached to the drum 42. The holder 110 comprises an upper surface 111, a lower surface (major surface substantially parallel to upper surface 111 but not shown) and a central mount aperture 113. Holder 110 further comprises a leading threaded opening 114 and a trailing threaded opening 116. Threaded fasteners, such as bolts, engage the leading threaded opening 114 and a trailing threaded opening 116. As illustrated, the cutouts 102 and holders 110 are rectangularly shaped. Other cutout shapes could be used and are within the scope of the present invention.
As best illustrated in the exploded view of
Each tooth 500 is attached to the leading surface 138 of a mount 120. Exemplary tooth 500 comprises a body having a generally flat leading middle surface 150 with an upper angled grinding surface 152 adjacent the middle surface 150 and a lower angled grinding surface 154 adjacent the middle surface 150, with the leading middle surface 150 therebetween as illustrated and a back surface 148 having a geometry. The flat leading middle surface 150 of each tooth 500 comprises an aperture 156 therethrough which is aligned with mount 120 aperture 142 when properly positioned for attachment to the mount 120.
As described above, leading surface of the mount 138 may comprise a geometry that is complementary to the raised central section 144 with adjacent side-stepped sections 146. Each tooth 500 may comprise complementary structure on its back surface 148. Thus, the back surface 148 of the illustrated embodiment of tooth 500 comprises a central groove 160 disposed vertically along the back surface 148, with adjacent side surfaces 162. This central groove 160 may engage and receive the complementary raised central section 144 of the mount 120, and the adjacent side surfaces 162 may engage the respective and complementary adjacent side stepped sections 146 of the illustrated embodiment of mount 120, thus ensuring proper alignment and assisting in keeping the tooth 500 in proper position during fragmenting. As illustrated, a bolt is threaded through aligned apertures 156 and 142, tightened against the trailing surface 140 of mount 120 with nut N to attach tooth 500 to mount 120. With some tooth styles, the tooth 500 may be threaded to accept a bolt inserted from the back of the mount 120.
Now looking at
A metallic coating is placed on at least a portion of the working surface 520. In one embodiment, the portion provided with the metallic coating includes at least three claws 522, 523, 524 on the first edge 521 and the at least three claws 527, 528, 529 on the second edge 526. In another embodiment, the working surface 520 is provided with the metallic coating. In one example embodiment, substantially the entire exterior of the tooth 500 is provided with the metallic coating, except the attachment surface 538.
In one embodiment, the metallic coating is a welded overlay. Weld overlays are metallic coatings welded directly onto the substrate. The high-heat welding process forms a molecular-level bond with the base metal, essentially alloying the coating to the substrate at the interface. The result is a durable, almost completely nonporous and impenetrable coating with excellent resistance to high-stress gouging wear.
Weld overlays are typically applied in greater thicknesses than thermal sprayed coatings. As such, substantial amounts of material may be applied in a comparatively short time. The weld alloying process makes the applied material an integral part of a component's physical structure. By nature of the process, highly customized surfaces may be developed by layering and alloying several different materials. Once a coating has been welded onto a substrate, it is virtually impervious to the problems of coating separation, lifting, and peeling that can sometimes occur in thermal sprayed coatings under high stress. The alloyed material also combines the high resistance to sliding abrasion offered by thermal sprayed coatings with an equally exemplary resistance to gouging and plowing wear.
During weld overlaying, the parts are exposed to high surface temperatures (in excess of 2,300° F.) and must be resistant to thermal deformation. Consideration needs to be given to any prior heat treatment of the substrate material and the thermal effects of the welding process on substrate metallurgy. Careful control of preheat, interpass and post-weld heat treat temperatures may be required for certain substrate alloys in order for the weld overlay process to be successful. Coefficients of expansion for the base metal and applied coating should be similar. Dissimilar coefficients can lead to cracking in the coating and possible damage to the component as the material and substrate cool.
In one embodiment, the metallic coating is a hardfaced weld overlay. The tooth 500 in
A tooth made from a casting of one material and then provided with a welded overlay or a hardfaced welded overlay is not as sharp as a tooth with added carbide inserts. However, the claw type tooth is able to fragment materials and last longer in a fragmentation device or a fragmentation environment. The claws 522, 523, 524, 527, 528, 529 present a larger surface area or working area for fragmenting materials. The tooth 500 with a metal overlay or a hardfaced metal overlay is less costly to manufacture. The cast tooth 500 does not have to be machined so that it can receive an insert, such as a carbide insert. The tooth 500 is, therefore, easier and less costly to manufacture. It also wears longer so that the teeth 500 on a fragmentation device do not have to be replaced as often. The result is less downtime for a fragmentation device.
Of course, adding the tooth or teeth 500 to holders on a drum forms a rotational fragmenting device, such as the fragmenting rotor 40. Additionally, adding a feed chute and other chambers and screens also forms a more extensive fragmentation device 10.
The present invention should not be considered limited to the particular examples described above, but rather should be understood to cover all aspects of the invention. Various modifications, equivalent processes, as well as numerous structures to which the present invention may be applicable will be readily apparent to those of skill in the art to which the present invention is directed upon review of the present specification.
| Number | Date | Country | |
|---|---|---|---|
| 63020382 | May 2020 | US |
