Abstract:
A chipping machine having an elongated, rotatable chipping member, the chipping member having at least one cutting blade and defining at least one blade opening adjacent the cutting blade. A paddle is provided on the chipping member which is associated with the blade opening and which extends radially with respect to the axis of rotation of the cutting member. The paddle preferably includes a tapered-in portion tapered inwardly toward the axis of rotation of the chipping member. A discharge chute is provided for receiving the chips cut from the article by the chipping member. The discharge chute preferably includes a generally semi-circular portion having a diameter greater than the chipping member and defines a chip path volume of generally semi-circular cross-sectional shape.

Description:
This application claims the benefit of U.S. Provisional application Ser. No. 60/141,417, filed Jun. 29, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates generally to a method and an apparatus for chipping large plastic items such as piping, conduit, etc. 
     In recycling polymeric articles such as polyethylene pipe, or other products made of polyethylene, polypropylene, nylon, polybutylene, etc., the products, once reduced to chips of manageable size, are fed into a granulator machine for grinding and subsequent reuse in molding processes, to produce new articles. A problem arises in how to reduce large polymeric articles, such as polyethylene pipe, which may be several feet in diameter, into pieces or chips small enough to be handled by the granulator machine. 
     The conventional method involves cutting the pipe with a band saw into manageable sections which can then be split into chips or pieces small enough to be used by the granulator. This is a labor-intensive and time-consuming process. 
     Devices for chipping wood products are known. For example, U.S. Pat. No. 3,856,212, issued to Swatko, discloses a wood chipper having a disc with blade portions angled towards a shaft and openings for discharging the chips through the disc. U.S. Pat. No. 3,635,410, issued to Smith, discloses a wood chipper having an intake chute at an angle with respect to a wood chipper disc. 
     U.S. Pat. Nos. 5,020,759 and 3,844,489, both issued to Strong, discloses rollers for supporting logs being fit into a wood chipping machine. 
     The foregoing known wood chipping devices, however, are not designed for chipping large plastic articles, such as polymeric, and in particular polyethylene pipe, and according, there exists a need for such a device. 
     SUMMARY OF THE INVENTION 
     It is, therefore, the principal object of this invention to provide a device for chipping polymeric articles. 
     Another object of the present invention is to provide a device for chipping polymeric pipe. 
     Yet another object of the present invention is to provide an improved chipping device which can be used to chip polymeric or wood articles. 
     Still another object of the present invention is to provide a method for chipping polymeric articles. 
     Generally, the present invention includes a chipper having an intake chute for receiving articles, and in particular polymeric pipe, the intake chute including a live roller conveyer for supporting the pipe as it is drawn into the chute. A rotating chipper disc, or blade, is provided which is driven by a diesel or gas engine, electric motor, hydraulic motor, or the like. The intake chute is disposed at an angle with respect to the chipper blade such that during operation, once the chipper blade engages the polymeric article or pipe to be chipped, such pipe or articles are pulled into the machine by the blade automatically due to the angle at which the intake chute is disposed with respect to the chipper blade. This angle may be approximately 30°. Thus, by having the pipe or other article approach the chipper blade at that angle, the pipe or other article is continually drawn into the chipper by rotation of the chipper blade. 
     Another feature of the present invention is the provision of a discharge chute designed for discharge of polymeric chips. The discharge chute is attached to the housing of the chipper device adjacent the chipper blade such that as plastic pipe and articles which pass through openings in the chipper blade, and which are sheared there through interaction of the opening and one or more bed knives provided in the chipper device, the chips thus created are propelled away from the chipper blade by a series of paddles carried on the backside of the chipper blade. These paddles kick the plastic chips upwardly, tangentially with respect to the chipper blade, and to the discharge chute. 
     The chute is designed to guide and constrain what in essence is projectile motion of the chips, meaning that the chips follow an arcuate path which is first directed upwardly, but which then curves downwardly towards the opening of the chute. This configuration of the discharge chute allows for increased throughput of plastic chips, as would be compared to a discharge chute ordinarily found in a wood chipper. 
     The present invention also includes a chipper disc which has modified paddles as compared to those used on a conventional wood chipping devices. The chipper disc has been modified to include paddle extensions which cause the paddles to taper inwardly towards the shaft on which the chipper blade rotates. These tapered-in portions of the paddles reduce the likelihood of one or more chips becoming jammed adjacent the backside of the chipper blade. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing, as well as other objects of the present invention, will be further apparent from the following detailed description of the preferred embodiment of the invention, when taken together with the accompanying specification and the figures, in which: 
     FIG. 1 is a perspective photographic view of a plastic chipping machine constructed in accordance with the present invention; 
     FIG. 2 is a is a perspective photographic view of the plastic chipping machine shown in FIG. 1; 
     FIG. 3 is a schematic side elevational view of a plastic chipping machine constructed in accordance with the present invention, which includes a discharge chute having an open side; 
     FIG. 4 is a schematic plan view of a plastic chipping machine constructed in accordance with the present invention, having a discharge chute which flares to prevent material from jamming; 
     FIG. 5 is a schematic front elevational view of a chipping blade constructed in accordance with the present invention, having four blade pockets; 
     FIG. 6 is a schematic side elevational view of the chipping blade, or impeller, shown in FIG. 5, having paddle extensions; 
     FIG. 7 is an exploded view of a prior art wood chipping machine; and 
     FIG. 8 is an exploded view of a prior art discharge chute for a wood chipping machine. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The accompanying drawings and the description which follows set forth this invention in its preferred embodiment. However, it is contemplated that persons generally familiar with wood chippers and plastic granulators will be able to apply the novel characteristics of the structures illustrated and described herein in other contexts by modification of certain details. Accordingly, the drawings and description are not to be taken as restrictive on the scope of this invention, but are to be understood as broad and general teachings. 
     Referring now to the drawings in detail, wherein like reference characters represent like elements or features throughout the various views, the chipper of the present invention is indicated generally in the figures by reference character  100 . 
     FIG. 1 illustrates a plastic chipping device constructed in accordance with the present invention. It should be noted at the outset that the chipping device  100  is based on a conventional, prior art wood chipper, and specifically, a 75-inch Morbark chipper manufactured by Morbark Industries, Inc., Box 1000, Winn, Mich. 48896. Further, the Morbark chipper, is illustrated in its  Operators Manual and Parts Manual , the entire contents of both the Operators Manual and the Parts Manual being incorporated herein by reference thereto, and both manuals form a part of and are incorporated by reference in the provisional patent application first noted above, namely U.S. Provisional patent application Ser. No 60/141,417, filed Jun. 29, 1999, of which this application claims benefit. FIGS. 7 and 8 from the  Parts Manual  illustrate the basic chipping device as including an infeed spout  20 , which is attached to a base  15 . A three blade, or knife, chipper disc  12  is provided for chipping wood delivered to it. The wood chips pass through the chipper disc and are engaged by paddles (not shown) on the backside of the chipper disc. These chips are then kicked or propelled by the paddles outwardly through a discharge spout assembly such as shown on page  6  of the Morbark parts manual. 
     Turning to FIG. 2 of the present invention, it can be seen that a power source, such as a 450 horsepower diesel engine  104 , is provided for powering rotation of the chipper disc  102  (FIGS. 5 and 6) within chipper  100 . Engine  104  drives the chipper disc via a belt  108  connected to a driving sheave or pulley  110  carried within shroud  112 . 
     The chipper  100  includes a modified intake chute  114  having an enlarged inlet end  118  for receiving whole pipe P or longitudinal segments of pipe up to 23 inches in diameter or in width dimension. There is no real limitation as the to length dimension of the pipe or pipe segments, or other polymeric articles, which may be inserted into intake chute  114 . Once inside of intake chute  114 , the pipe P or other article is carried by a series of rollers  122  (only a several of which are shown for illustrative purposes), which support the pipe P or other article as it is drawn into the chipper blade, or disc  102 . 
     It should be noted that as with the Morbark chipper, the intake chute angle has been maintained with respect to the plane in which chipper blade  102  rotates at an angle approximately a, which is preferably approximately 30°. By disposing intake chute  114  and, consequently, the feed angle of stock being fed to chipper blade  102  at this angle, the shearing of chips from the article induces a pulling force having linear components in the direction of the material being fed, thus causing the material to be automatically drawn into the chipper blade as the chipper blade rotates. This is particularly true in the case of polyethylene pipe and segments. 
     FIG. 3 illustrates discharge chute  124  connected to the hood  128  around chipper blade  102  and the semi-circular profile of discharge chute  124 . Discharge chute  124  defines a large interior portion which allows for a much greater volumetric area through which the chips pass prior to exiting discharge opening  130  of discharge chute  124 . By providing this much larger area than would ordinarily be found with discharge chutes of wood chippers, clogging of the plastic chips within the discharge chute  124  is greatly minimized. 
     Discharge chute  124  includes a generally semi-circular upper wall  132  and two generally flat side walls  134 . This arched curvature of wall  132  allows the chips C to follow projectile or parabolic-like motion as they are propelled by disc  102 . Chute  124  is large, and is actually taller than hood  128 . This gives further volume and elevation through which the chips may fly. Chute  124  is also longer than hood  128  to, again, give further room for chip movement, in order to reduce clogging. Chute  124  also flares outwardly towards opening  130  to further reduce the likelihood of chips C jamming in chute  124 . Discharge opening  130  is a generally horizontally disposed square opening and is preferably longer than the diameter dimension of chipper blade  102 , and lower wall  138  of discharge chute  124  extends from discharge opening at an angle to the base of chipper  100 . 
     Discharge chute  124  is designed to mate with the discharge opening of the Morbark chipper. However, it is to be noted that the hood  128  of chipper  100  has been significantly modified to allow a much larger exit opening than is the case with the conventional Morbark chipper. As shown in the drawings, discharge chute  124  extends well above the height of the axle  140  of the chipper disc. This is not the case with the Morbark opening, the upper edge of which is generally in line with the center of the chipper disc. Thus, practically speaking, the discharge chute side of the chipper hood has a significantly larger open portion to provide a continuous opening from lower wall  138  of discharge chute  124  to the interface of upper wall  132  of discharge chute  124  and hood  128 , notably at  142  in FIGS. 3 and 4. FIG. 4 also shows the angled disposition of intake chute with respect to base  150  of chipper  100 . 
     FIG. 5 illustrates four blade openings, or pockets,  152  provided in chipper disc, or impeller,  102  of chipper  100 . Chipper disc  102  is carried for rotation on axle  140  (FIG.  6 ), axle  154  being connected to pulley  110  for being driven by motor  104 . 
     Blade openings  152  work in connection with cutting blades  170  and a bed knife, such as disclosed in the  Morbark Operators Manual . The bed knife is identified as knife  30  in the  Morbark Parts Manual.    
     FIG. 6 illustrates the Morbark chipper disc as modified for the present chipper  100 . Tapered-in paddle extensions, generally  160 , have been added to each paddle  162  provided on the Morbark chipper disc. Note that while not shown, the chipper disc  102  includes cutting blades, such as blades  30  shown in FIG. 7, on the intake side thereof. These paddle extensions  160  minimize accumulation of polymeric or plastic chips in the region between the paddles  162  and shaft  154  or boss  164 , which could lead to jamming of the chipper disc, should such chips build up in hood  128 . 
     It is to be understood that although chipper  100  has been developed based on a Morbark 75-inch chipper, other conventional wood chipping machines could also be likewise converted and made suitable for chipping polymeric pipe and other articles. Further, chipper  100  could be constructed new, without modifying a conventional chipper, by applying the teachings and features discussed above with respect to chipper  100 . This would thereby yield a machine different in appearance than that disclosed in the present drawings, but which provides the same functionality in chipping polymeric and other plastic item. 
     It should also be noted that the chipper  100  could be used to chip wood products, if desired. 
     In operation, a length of polymeric pipe P or other article is inserted into intake chute  114  to be supported on rollers  122 . Once the end of such pipe P or article engages with chipper disc  102 , chips are removed from the article, and the article is propelled inwardly due to the angular relationship of chute  114  and chipper disc  102 . Chips C removed from the article are propelled outwardly from the area of hood  128  by paddles  162  of chipper disc  102 . The chips then fly through discharge chute  124  and outwardly from discharge opening  130 . The chips thus discharged are then ready for feeding into a conventional granulator. 
     While preferred embodiments of the invention have been described using specific terms, such description is for present illustrative purposes only, and it is to be understood that changes and variations to such embodiments, including but not limited to the substitution of equivalent features or parts, and the reversal of various features thereof, may be practiced by those of ordinary skill in the art without departing from the present disclosure and claims.