Abstract:
A mechanical separator having a primary frame, a tray frame linked to the primary frame, and an oscillator linked to the tray frame for imparting relatively short period reciprocating and/or orbital motion thereto. The tray frame includes a plurality of tines preferably rigidly linked at their proximal ends to one end of the tray frame, and a supporting cross member that permits restricted motion of the tines when subject to kinetic impetus. The supporting cross member preferably defines holes through which the tines pass, and the distal ends of the tines are preferably free to move, being only restricted in motion by the supporting cross member. The tray frame is preferably suspended from the primary frame by extension members, which also provide for tilt, elevation and vibration isolation features.

Description:
BACKGROUND OF THE INVENTION 
   The mechanical separation of constituents comprising a commingled material has been an ages old art. These separation actions have applied to food, such as separating wheat from chaff; or to minerals, such as separating gold from gold-bearing gravels. It has also applied to the separation of animal excrement from the animal&#39;s bedding. While in some areas there is an abundance of inexpensive bedding for animals wherein soiled bedding may be disposed of, for the most part, bedding is reused at least once by separating the feces there from. 
   The traditional means for carrying out such mechanical separation of feces from bedding has relied upon manual efforts in combination with a manure fork or other tined tool where the manure is thrown into a muck bucket or wheelbarrow. Standard manure forks for horse stalls have 18 tines, spaced about 0.75 inches apart, allowing manure particles smaller than about 0.75 inch to fall through with the used bedding. It has been estimated that approximately 20% of the manure is left behind. Newer forks with 30 tines spaced about 0.375 inches apart are an improvement, but by some measurements still allow about 15% of the manure to remain and increase the time and effort to conduct the required separation actions. 
   While generally effective, hand picking is tedious and time consuming. The average time to clean a horse stall is 15 to 20 minutes if done well. However, if one is required to clean many stalls over a long period of time, the manual method takes its toll on the body and can cause tennis elbow, carpal tunnel syndrome and chronic back pain. To minimize these deleterious consequences of hand picking, the cleaner will often throw good bedding away with the waste, or fail to remove all of the waste. In other words, time can be saved at the expense of bedding or bedding can be saved at the expense of time. 
   To address these deficiencies, power assisted mechanical separators have been developed and used. The general approach has been to emulate the process of manually mechanically separating the feces from the bedding. In this respect, these efforts have been generally successful. However, there continues to be constraints in the prior efforts of achieving a high efficiency power assisted mechanical separator, most notably the amount of kinetic energy imparted by the sifting surface to the bedding, as well as adaptability of such devices in light of changing environmental conditions such as relative humidity, temperature, and moisture content of the bedding, moisture content of the feces, binding of the feces, etc. 
   SUMMARY OF THE INVENTION 
   The invention is directed to mechanical separator particularly for use in separating animal bedding material from animal excrement. Embodiments of the invention comprise a primary frame, a tray linked to the frame, and an oscillating means for imparting relatively short period reciprocating and/or orbital motion to the tray. The tray is preferably inclined at an angle between the horizontal and vertical so that material placed on the tray will seek one end thereof during oscillation of the tray, as will be described in detail below. 
   The primary frame of various embodiments of the invention is constructed to retain the tray, whether in a preferably suspended relationship therewith, pivotally or rigidly. The frame may be adapted to receive a container located below the tray to retain material falling from the tray during operation of the mechanical separator. In addition, if the tray is pivotally linked to the frame, the frame may also provide for tray pivot clearance. Enhancements to the frame include provisions for wheels to assist in the movement of the frame, and antifriction surfaces on portions of the frame that may abut the tray. 
   In suspended embodiments of the invention, extension members link at least a portion of the tray to the frame such that the tray is vertically displaced from the frame. In certain embodiments, one end of the tray is pivotally attached to the frame while an opposing end is suspended from the frame, while in other embodiments the tray is fully suspended from the frame by extension members. The extension members may have a plurality of attachment points there on for receiving the tray at desired elevations relative to the frame. If a higher degree of isolation between the frame and the tray is desired, one or more of the extension members may be constructed from a flexible material, such as reinforced rubber. 
   The tray of various embodiments of the invention includes a tray frame comprising an end wall and preferably two sidewalls extending away there from. In one series of embodiments, the optional sidewalls are attached to the end wall, and generally extend orthogonally there from, to form an open-ended or “U” shaped perimeter. The tray further includes a plurality of tines, each tine having a longitudinal axis generally orthogonal to the major axis of the end wall, although such alignment is not necessary to the successful operation of the invention. At least some, and preferably all, tines are coupled to the tray at the end wall and/or the optional sidewalls. The coupling may be loose, i.e., captively coupled but not rigidly coupled, may be rigid, and/or may be a combination of loose and rigid, depending upon the location. 
   As noted in the preceding paragraph, association of the tines with the tray frame may take many forms and still be within the scope of the invention. It is only required that the tines be captively associated with the tray frame. Thus, at least some of the tines may be directly linked to the end wall, or may be linked to the sidewalls through a cross member. For optimal operation of the invention, it is desirable to have one end or portion approximate thereto of each tine linked to the tray frame, whether the end wall or the sidewalls. In a preferred series of embodiments, the ends of the tines are rigidly linked to the end wall of the tray frame. 
   The tines are further supported by a supporting cross member disposed between the linked ends and an opposite end, and which is itself linked to the sidewalls. This supporting cross member is preferably characterized as having a plurality of holes formed therein, where the holes are preferably, but not necessarily, linearly aligned. The diameter of these holes is greater than the outside diameter of the tines whereby the tines are free to move in directions other than axially within the holes. Those persons skilled in the art will appreciate that alternative configurations exist that may accomplish the same or similar results, and include slots formed in the cross member wherein the slots have a width dimension greater than the outside diameter of the tines, pairs of converging or diverging slots that cause the tines to “pinch” material placed thereon, and a plethora of other geometric shapes that may be employed depending upon use considerations. Moreover, the cross member need not captively retain the tines, but instead may vertically support and laterally restrain the tine, such as when the supporting cross member is formed by “U” or “L” shaped channel and slotted accordingly. 
   In a preferred series of embodiments, the supporting cross member is not positioned at or adjacent to the distal end of the tines (opposite the attached or proximal ends). In this manner, a portion of the tines are “free” or cantilevered. This arrangement maximizes the movement of the tines when the tray is oscillated or otherwise caused to shake or vibrate. This relative freedom of movement enhances the separation actions of the apparatus, and further causes aggregated clumps of material placed on the tines to break apart, thereby enhancing the operation of the apparatus. 
   Also in a preferred series of embodiments, the supporting cross member is removably linked to the sidewalls. In this manner, it can be disassociated from the tines with relative ease, thereby facilitating cleaning of the tines since no obstructing structure is present from the attached ends to the free ends. 
   Embodiments of the invention further comprise oscillating means for imparting relatively short period reciprocating and/or orbital motion to the tray. These means may be manually derived, such as by a shaking motion imparted by a user&#39;s hand, or may comprise an electric vibrator attached to the tray frame or primary frame. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of an embodiment of the invention showing a variable elevation/inclination mechanical separator; 
       FIG. 2  is a partially exploded perspective view of the embodiment shown in  FIG. 1 . 
       FIG. 3  is a side elevation view in partial cross section of the embodiment shown in  FIG. 1  during mechanical separation of manure from a bedding material; 
       FIG. 4  is a detailed, partially exploded perspective view of the sidewall to supporting cross member interface to permit removal of the cross member from the sidewall. 
       FIG. 5A  is a detailed cross section elevation view of the range of vertical movement of a tine within a supporting cross member and having circular holes; 
       FIG. 5B  is a detailed cross section plan view of the range of horizontal movement of the tine within the supporting cross member of  FIG. 5A  taken substantially along the line  5 B- 5 B; 
       FIG. 6A  is a partial elevation view of a supporting cross member having circular holes; 
       FIG. 6B  is a partial elevation view of a supporting cross member having elliptical holes with the ellipse major axis being orthogonal to the tine axis; 
       FIG. 6C  is a partial elevation view of a supporting cross member having elliptical holes with the ellipse major axis being parallel to the tine axis; 
       FIG. 6D  is a partial elevation view of a supporting cross member having elliptical holes with the ellipse major axis being oblique and acute to the tine axis; 
       FIG. 6E  is a partial elevation view of a supporting cross member having generally triangular holes with the apex pointed “up”; and 
       FIG. 6F  is a partial elevation view of a supporting cross member having generally triangular holes with the apex pointed “down”. 
       FIG. 7A  is a partial perspective view of a first alternative supporting cross member for generally retaining a plurality of tines; and 
       FIG. 7B  is a partial perspective view of a second alternative supporting cross member for generally retaining a plurality of tines. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The following discussion is presented to enable a person skilled in the art to make and use the invention. Various modifications to the preferred embodiment will be readily apparent to those skilled in the art, and the generic principles herein may be applied to other embodiments and applications without departing from the spirit and scope of the present invention as defined by the appended claims. Thus, the present invention is not intended to be limited to the embodiment shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein. 
   Turning then to the several Figures wherein like numerals indicate like parts, and more particularly to  FIGS. 1 and 2 , a mechanical separator embodiment of the invention is shown. Separator  10  comprises frame  20 , separating tray  50  and vibrator  80 . Unless otherwise noted or apparent to persons skilled in the art, all described components are constructed from mild steel, chosen for its durability and ease of fabrication. Structural parts are preferably welded, although substitution of other fastening means will also permit the skilled practitioner to reproduce the illustrated embodiment. 
   Although a variety of forms are possible, frame  20  is shown as having longitudinal rails  22   a  and  22   b , to which are attached horizontal cross members  24   a  and  24   b  in the horizontal plane, and generally vertical struts  30   a - d . While struts  30   c  and  30   d  are generally vertical, struts  30   a  and  30   b  are diverge from the vertical away from tray  50 . This geometry advantageously provides desirable clearance for tray  50  during operation of separator  10  and further moves the center of mass slightly back towards wheels  28   a  and  28   b , thereby lessening the burden on a user when positioning separator  10  into the transport position. Additionally, frame  20  is dimensioned so as to fit within most common passageways, and in the illustrated embodiment, the width is selected as 28 inches. 
   As intimated above, separator  10  is intended for convenient transportation, such as from one horse stall to another. Wheels  28   a  and  28   b , which are rotationally linked to axle  26 , provide the means for achieving this objective while the depending portions of struts  30   c  and  30   d  provide desired ground contact, thereby enhancing stability while reducing weight. 
   Support for separating tray  50  is provided by connecting rails  32   a  and  32   b  via resilient extension members  40   a - d . Rigidity is maintained by hand rail  36 , which is firmly linked to connecting rails  32   a  and  32   b  and preferably includes a resilient gripping surface, since there is no corresponding structure at the opposite end thereof. Additional rigidity is provided by bracing cross members  38   a  and  38   b . The relative elevation and constitution of these bracing cross members is primarily driven by the need for rigidity and clearance of tray  50  during all operating positions, as well as the need for access under tray  50 . 
   The relative position and orientation of separating tray  50  relative to frame  20  is predominantly controlled by extension members  40   a - d . Each extension member  40  is preferably constructed from a fabric reinforced rubber material that provides sufficient resistance to creep and sufficient load bearing properties, yet effectively isolates movement of the tray from the frame. Furthermore, each extension member  40  preferably defines a plurality of longitudinally aligned holes for receiving fasteners or other mounting means, as will be described in more detail below. 
   As best shown in  FIG. 2 , each member  40  is linked to one of connecting rails  32   a  or  32   b  at one of a plurality of mounting locations. While the preferred linkage means is by way of bolt and nut fasteners, the skilled practitioner will recognize that alternative linkage means are possible, and include using mounting studs extending from the connecting rails, as opposed to forming holes therein. It is therefore only necessary to the operation of the illustrated embodiment that extension members  40   a - d  be linked to frame  20 . The alternative mounting locations provide the user with greater flexibility regarding the location of the apparatus center of mass, relative lateral position of the tray to the frame, etc. Similarly, each member  40  is linked to one of sidewalls  54   a  or  54   b . In the illustrated embodiment, studs project from the outer portion of sidewalls  54   a  and  54   b , as well as a portion of collars  68   a  and  68   b.    
   To provide for vertical and inclination adjustment of separating tray  50 , a plurality of alternative mounting locations in the form of holes are defined by each resilient extension member  40 . As  FIG. 3  clearly illustrates, the inclination of separating tray  50  can be modified by changing the points of linkage between at least two members  40  and preferably sidewalls  54 . In this manner, the performance of separator  10  can be easily modified in view of changing environmental conditions such as temperature and humidity, as well as changing conditions of the materials to be separated. 
   Separating tray  50 , which is preferably constructed from stainless steel or similarly corrosion resistant and durable material, comprises frame  52 , which includes opposing sidewalls  54   a  and  54   b , and end wall  58 , which serves to connect the ends of sidewalls  54   a  and  54   b . Disposed between sidewalls  54   a  and  54   b  are a plurality of tines  60 . Tines  60  are linked to frame  52  by way of channel  62  and tubular support  64 . 
   Channel  62 , which is fixedly attached to end wall  58 , is sized to receive tines  60 . A plurality of holes may be formed in the web portion of channel  62  to receive end portions of tines  60  where the end portions may be welded or held captive therein, such as by Circlip or other means. These holes may be sized to closely fit the tine ends, or may be oversized so that the tines are loosely held therein. Alternatively, tines  60  may be welded to one or both legs of channel  62 . The selection of ultimate linkage depends upon several facts that will be discussed in greater detail below. 
   Tubular support  64  is preferably removable linked to sidewalls  54   a  and  54   b  as best illustrated in  FIGS. 2 and 4 . Collars  68   a  and  68   b  (only  68   g  being shown) preferably extend on either side of respective sidewalls  54   a  and  54   b  as best shown in  FIG. 4 , which beneficially provides an attachment means for use with extension members. The inner portion of each collar  68   a  and  68   b  includes respectively through holes  69   a  and  69   b  (only  69   b  being shown) for receiving hitch pin clip  70 . The inner diameter of each collar is sized to translationally receive an end of tubular support  64 , which also includes through holes  65   a  and  65   b  (only  65   b  being shown), and remain selectively captive therein as illustrated. 
   Tubular support  64  is characterized as a generally tubular member having a plurality of spaced-apart holes  66  sized to loosely receive tines  60 . This loose fit permits material vertical and horizontal displacement of each tine  60  within each hole  66 , as best shown in  FIGS. 5A and 5B . This range limited freedom of motion provides enhanced mechanical action beneficial to the separation of aggregated material, such as animal excrement and bedding material. 
   Depending upon circumstances, it may be desirable to tailor the quality and/or degree of tine motion during operation of separator  10 . To this end, the geometry and size of holes  66  can be modified to alter the nature of tine motion and/or the magnitude of tine motion.  FIGS. 6A-F  illustrate alternative hole geometries that, depending upon environmental conditions, may be particularly suited for the objectives of the user.  FIG. 6A  illustrates generally circular holes  66 A;  FIG. 6B  illustrates elliptical holes  66 B wherein the major axis of the ellipse is in the vertical direction;  FIG. 6C  illustrates elliptical holes  66 C wherein the major axis of the ellipse is in the horizontal direction;  FIG. 6D  illustrates pairs of diverging or converging (depending upon the grouping) holes  66 D;  FIG. 6E  illustrates generally triangular holes  66 E with the apex in the “up” direction; and  FIG. 6F  illustrates inverted triangular holes  66 F. As noted above, the magnitude of tine motion is also very much affected by the size in a single or multiple directions of the holes. 
   Those persons skilled in the art will also appreciate that alternative support members can be used, and include slotted channels or pegged stock, which are shown in  FIGS. 7A and 7B  where a slotted channel  164  is shown in conjunction with supported tines  60  and a pegged rod  264  is shown in conjunction with supported tines  60 , respectively. However, particular advantages are found in the primary embodiment, and include reduced binding due to detritus accumulation and lack of exposed edges. 
   In addition to the foregoing, additional tubular supports can be introduced into tray  50  to modify the separation effect of the illustrated embodiment. In these embodiments, however, it is not necessary although not improper, to have the supports be removable or to have collars extend to the outside of sidewalls  54   a  and  54   b.