Patent Publication Number: US-2005139133-A1

Title: Granular spreader and product container

Description:
This application is a continuation-in-part of Ser. No. 09/189,555, filed Nov. 11, 1998. 
    
    
     BACKGROUND OF THE INVENTION  
      The present invention is directed to methods and apparatus for dispersing material, particularly granular chemical material. The invention is particularly adapted for dispensing agricultural treatment material, such as pesticides, herbicides, fungicides, and fertilizer from an apparatus driven over the terrain onto which the treatment materials are to be applied.  
      Agricultural dispensing apparatus, more commonly known as granular spreaders, generally include a wheeled vehicle, either self-powered (e.g., motorized) or manually driven, including a housing having a hopper for receiving a container holding the product to be dispersed, and metering means for controlling the quantity of material flowing from the product container, by gravity feed, and onto dispersing means, such as a rotating plate, positioned beneath the metering means for receiving material deposited thereon. The apparatus is driven along terrain to be treated, and the material to be applied to the terrain is dispersed from the moving apparatus by the rotational forces applied by the rotating plate.  
      Known agricultural spreaders exhibit disadvantages which include: variations in the rotational speed of the dispersing plate (and thereby variations in the distance which material is propelled from the spreader) in proportion to changes in the linear speed of the spreader; imprecise metering of material deposited on the disperser plate from the product container during repeated dispersing operations; the inability to control the angular orientation at which material is dispersed from the spreader; and the inability to automatically disengage the metering means from the disperser plate to prevent material from being deposited on the disperser plate when the spreader is moved in a reverse direction.  
      It is the primary object of the present invention to provide an improved spreader, particularly for dispensing granular agricultural materials onto terrain over which the spreader is driven, which overcomes the aforementioned disadvantages, and others, encountered in the operation of known dispersing apparatus. Other objects and advantages of the methods and apparatus in accordance with the present invention will become apparent from the following description of the invention in conjunction with the drawings.  
     SUMMARY OF THE INVENTION  
      The present invention provides methods and apparatus for dispensing material, and in particular granular agricultural treatment material, from a moving disperser device. The device includes a housing, at least a pair of wheels mounted to the housing for driving the housing over the ground, and a handle by which the device can be driven. The vehicle may be either self-powered or manually driven, and includes a housing having a hopper for removably receiving a product container with the material to be dispersed. Metering means are provided to control the flow of material, by gravity feed, from the hopper and onto a spinning impeller therebelow for propelling the material from the moving apparatus. The metering means includes an apertured disk defining a plurality of concentric rows of vertical channels, each of the vertical channels having opened upper and lower ends. A discharge plate defining at least one opening thereon is mounted below the metering disk, and is operatively associated with the metering disk such that rotational movement of the metering disk relative to the discharge plate selectively covers and uncovers the openings in the lower ends of selected vertical channels in the metering disk. When the lower openings of the channels are uncovered, material in the channels is permitted to flow through the opening in the discharge plate, by gravity feed, to be deposited onto a rotatable impeller therebelow. A charging plate having at least one opening is mounted above the top of the metering disk such that rotational movement of the metering disk relative to the charging plate uncovers the upper ends of selected vertical channels in the metering disk. In this relative position, material from the hopper flows, by gravity feed, through the opened portion of the charging plate to fill each of the selected uncovered vertical channels in the metering disk to its maximum volume. During the filling procedure, the discharge plate beneath the metering disk covers the lower ends of the vertical channels being filled to prevent the material from dropping through the channels. When the channels are filled to full capacity, the metering disk is rotated such that the charging plate covers the top openings in each filled vertical channel to sweep excess material therefrom and to prevent further material from being deposited therein. The discharge plate beneath the metering disk is oriented relative to the charging plate so that when the metering disk rotates relative to the charging plate to cover the upper ends of the filled channels, the metering disk simultaneously rotates relative to the discharge plate to uncover the lower ends of the vertical channels to permit the material in the filled channels to drop downwardly, by gravity feed, onto the rotatable dispersing impeller therebelow. In this manner, a uniform, repeatable quantity of material, corresponding to the volume of the filled vertical channels defined in the metering plate, is sequentially deposited on the dispersing impeller during each filling and metering operation. A drive train couples the metering disk to a wheel of the spreader for imparting rotational movement to the metering disk so that material is metered at a rate corresponding to the linear speed of the spreader and is dispensed in uniform density over the terrain travelled by the spreader.  
      A selector plate is mounted beneath the discharge plate (which itself is mounted beneath the metering disk) for selectively blocking the lower openings of predetermined vertical channels in the metering disk for controlling the position on which material is deposited from the metering disk onto the rotatable impeller therebelow. The position at which material is deposited on the impeller is a parameter which affects the range or distance that the material deposited thereon is propelled as a result of applied rotational forces. The selector plate maintains the openings in the lower ends of predetermined vertical channels covered without regard to the position of the metering disk relative to the discharge plate, thereby effectively overriding the discharge plate when metering disk is rotated over an opened portion of the discharge plate to uncover the lower openings in the predetermined vertical channels. The selector plate also provides means for selectively blocking different overall sections of the metering disk to adjust the angular orientation at which material is propelled from the moving spreader by the rotatable impeller.  
      At least one wheel of the spreader is coupled to the impeller to impart rotational movement to the impeller as the spreader is driven over the terrain to be treated, and means are provided for maintaining the actual rotational speed of the rotatable disperser impeller constant and independent of the linear speed of the spreader. In this manner, the distance or range which material deposited on the rotating impeller is propelled, which is proportional to the rotational speed of the impeller, is maintained at a constant value which is selectively adjustable by adjusting the rotational speed of the impeller. In the preferred embodiments of the invention, the means for maintaining the rotational speed of the impeller at a constant value includes a plurality of weights which are movable in guide elements, by inertial forces, relative to the center of the impeller for opposing applied forces to the impeller tending to increase or decrease the rotational speed thereof.  
      The spreader, in its preferred embodiments, includes a clutch system and associated drive train coupled to one wheel of the spreader for automatically disengaging the meter assembly to prevent material from being deposited on the rotatable impeller when the spreader is moved in a predetermined direction (i.e., in reverse).  
      The present invention also provides an improved product container for removably mounting onto the hopper of the spreader. The lower portion of the container defines a compartment for accommodating a meter housing including the meter assembly discussed above. In the preferred embodiments of the invention, the container includes a transparent plastic product bag received within a container housing, and a clear section on the container housing to permit visual observation of the contents within the product bag. Because the meter housing and the removable product container are formed as a single unit which is removably mounted to the spreader, the meter assembly can be pre-set to the desired quantity of material to be metered, the desired rate at which material is to be metered, and the desired position at which material is to be deposited on the dispersing impeller, before the product container is mounted to the spreader.  
      In a further embodiment of the spreader apparatus and product container in accordance the present invention, the spreader includes override clutch means which permit a rotatable impeller to continue to rotate after movement of the apparatus has ceased for dispersing any material remaining on the impeller after the spreader has come to a halt. In this manner, excess residual product deposited on the impeller will not be dispersed from the impeller when the spreader apparatus resumes travel along the terrain to be treated and the impeller resumes rotation.  
      The spreader apparatus also includes a selector switch readily accessible to an operator for selectively adjusting the rotational speed of the impeller between two or more different pre-selected speeds for adjusting the distance or range which material is propelled from the rotating impeller. An on/off switch for disengaging a drive train coupling the wheels of the spreader to the impeller is operatively associated with the selector switch to assure that the rotational speed of the impeller can not be changed unless the drive train to the impeller is disengaged.  
      The spreader apparatus also includes a further switch readily accessible to the operator for controlling the area of terrain relative to the spreader apparatus on which material from the apparatus will be dispersed from the rotatable impeller. This switch enables the operator to selectively control the pattern of distribution of material from the impeller plate in a direction predominantly forward of the apparatus, in a direction predominantly to the left side of the apparatus, in a direction predominantly to the right side of the apparatus, in a direction to the rear of the apparatus, or equally distributed to the left and right sides of the apparatus, as may be required by the specific application being made by the spreader apparatus as it moves along the terrain to be treated. The switch also includes an “off” position in which no material is distributed. Visual indicia provide the operator with illustrations of the specific mode of operation corresponding to each of the different switch positions.  
      The spreader apparatus also includes means for enabling the operator to readily align and engage drive shafts in a meter assembly carried by “a product container and in the spreader apparatus to permit material to be metered from the product container and dispersed by the spreader as the spreader is moved along terrain to be treated. The spreader apparatus also includes guide elements for assuring that the selector plate which controls the distribution pattern of material dispersed from the spreader apparatus is maintained in proper position relative to the metering disk of the spreader apparatus to assure that the proper quantities of material are metered and deposited on the proper positions on the rotatable impeller.  
      The spreader apparatus also includes beveled edges on a clutch compartment enclosing a clutch forming part of the drive train between the wheels of the spreader and the rotatable impeller. The beveled edges of the clutch compartment enclose the clutch and tend to muffle and deflect sound waves generated by the clutch in a direction towards the inner surface of the spreader wheels to result in quieter operation of the spreader apparatus as it moves along the terrain to be treated.  
      The spreader apparatus also includes a drive train coupling the wheels of the spreader to the rotatable impeller having a drive belt with evenly spaced sprocket openings which are engaged by drive pins in a capstan to provide a more positive driving force than provided by O-ring belt designs.  
      The spreader apparatus also includes hinged flaps which are selectively movable between extended and retracted positions, respectively. The flaps are removably retained in either extended or retracted positions by retaining means which include complementary magnets mounted to the spreader apparatus and the flaps. The flaps are mounted to the left and right sides of the spreader apparatus and are provided to prevent product from drifting into undesired areas when an edge application of material is required during a treatment process.  
      In a further embodiment of a product container in accordance with the present invention, the product container can be formed from a molded plastic material so as to be re-usable during different treatment operations of the spreader apparatus. The container can be designed to include a lower rolling lip structure to be removably received in a flange of a meter assembly for readily connecting and disconnecting the meter assembly from the container. The container and the meter assembly include cooperating structure by which the meter assembly is maintained in a fixed position relative to the container when the meter assembly and container are coupled to each other.  
      The container also includes a domed or spherical partition mounted proximate to the bottom of the container for preventing the full weight of product in the container from being applied directly to the meter assembly carried by the bottom of the product container. This partition supports the weight of all product in the container positioned thereabove. The partition also includes at least one slot or aperture for controlling the downward flow of material from above the partition and onto the meter assembly positioned below the partition. The partition rotates together with the meter disk and tends to break up lumps of material into smaller granules as the material flows downwardly by gravity feed through the opening in the rotating partition.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  of the drawings is a side elevational view of a dispensing apparatus in accordance with the present invention, and a product container mounted to the apparatus in accordance with the present invention;  
       FIG. 2  is a front elevational view, in section, of the product container of  FIG. 1  removed from the apparatus;  
       FIG. 3  is a side elevational view, in section, of the product container illustrated by  FIG. 2 ;  
       FIG. 4  illustrates a side view of the product container, as illustrated by  FIGS. 2 and 3 , and a cover sealing the bottom of the container;  
       FIG. 5  is an expanded view of the lower right end portion of the container illustrated by  FIG. 2  showing, in detail, the manner in which components of the meter assembly are mounted to a meter housing proximate to the bottom end of the product container;  
       FIG. 6A  illustrates a bottom plan view of the product container illustrated by  FIGS. 2-5  with the meter assembly in a closed position, and  FIG. 6B  illustrates a bottom plan view of the product container with the meter assembly in a partially opened position;  
       FIG. 7A  is a top plan view of a metering disk of the meter assembly of the present invention;  FIG. 7B  is a side elevational view, in section, of the metering disk illustrated by  FIG. 7A ; and  FIG. 7C  illustrates the relationship between the metering disk and a charging plate operatively associated therewith;  
       FIG. 8A  illustrates a top plan view of a dispersing impeller in accordance with the present invention, and  FIG. 8B  illustrates a side elevational view, in section, of the dispersing impeller illustrated by  FIG. 8A ;  
       FIGS. 9A-9D  illustrate a one-way clutch system in accordance with the present invention;  
       FIG. 10  illustrates a front elevational view of a dispersing apparatus, in section, showing the clutch system of  FIGS. 9A-9D  coupled by a drive train to the meter assembly of the dispersing apparatus in accordance with the present invention;  
       FIG. 11  is a front elevational view of a further embodiment of a dispensing apparatus in accordance with the present invention;  
       FIG. 12  is a front elevational view showing the bottom detail of the dispensing apparatus illustrated by  FIG. 11 ;  
       FIG. 13  is a front elevational view showing the top detail of the dispensing apparatus illustrated by  FIG. 11 ;  
       FIG. 14  is a rear elevational view of the bottom detail of the dispensing apparatus illustrated by  FIG. 11 ;  
       FIG. 15  is a rear elevational view of the top detail of the dispensing apparatus illustrated by  FIG. 11 ;  
       FIG. 16  is a right side elevational view of the bottom detail of the dispensing apparatus illustrated by  FIG. 11 ;  
       FIG. 17  is a left side elevational view of the dispensing apparatus illustrated by  FIG. 11 ;  
       FIG. 18  is a left side elevational view of the lower detail of the dispensing apparatus illustrated by  FIG. 11 ;  
       FIG. 19  is a top view of the dispensing apparatus illustrated by  FIG. 11 ; and  
       FIGS. 20   a  and  20   b  illustrate, respectively, a bottom plan view and a front elevational view in section of a container used in conjunction with the dispensing apparatus illustrated by  FIG. 11 .  
    
    
     DESCRIPTION OF THE BEST MODES FOR CARRYING OUT THE INVENTION  
       FIG. 1  illustrates an overview of the dispensing apparatus in accordance with the present invention, and in particular, an apparatus for dispersing granular chemical material such as pesticides, and herbicides. The apparatus is driven over terrain to be treated, and the treatment material carried by the apparatus is applied to the terrain. The following discussion refers to the apparatus in accordance with the present invention as a “spreader” or an “agricultural spreader”.  
      The spreader in accordance with the preferred embodiments of the present invention is designated generally by reference numeral  2 . The major components of the spreader  2  include a hopper  4  provided for removably receiving a product container  6  holding the material to be dispersed by the spreader. A housing sleeve  8  is provided to receive a metering housing, to be discussed in greater detail below, integrally defined at the bottom of the product container  6 . The product container and metering assembly are therefore removably mounted to the hopper of the spreader as a single unit. An impeller assembly  10 , including a rotatable impeller, is disposed beneath the housing sleeve  8 , and a drive belt  12  operatively associated with a wheel  14  is coupled to the impeller assembly  10  for imparting rotational movement to the impeller, when the wheel  14  rotates as the spreader  2  is driven over the terrain designated by reference numeral  16 . (As will be described below, a drive system is also provided to impart rotational movement of the wheel to a metering disk rotatably mounted within the metering housing). A second wheel, mounted on the opposite end of an axle on which the first wheel  14  is mounted, is not shown in  FIG. 1 . The spreader also includes a vertical supporting element  18  to reinforce the structural integrity of the assembled device, and a handle  20  by which the device is driven by a user. The spreader  2  can be manually driven or self-powered (e.g., motorized). A lever  22  is mounted to the handle to permit the user to disengage the metering system to selectively prevent the application of material to the terrain by the spreader when the switch is in the off position.  
       FIG. 2  of the drawing illustrates a front elevational view, in section, of the product container  6  shown in  FIG. 1 , removed from the spreader apparatus.  FIG. 3  is a side elevational view of the product container  6  illustrated by  FIG. 2 . The product container  6  is formed from three major components—a container housing  24  which can be formed from a corrugated cardboard material; a product bag  25  mounted inside the housing  24 ; and a metering housing  26  integrally formed as a single unit with the product container  6  and mounted to a pyramid shaped flange  28  defined at the bottom of the housing  24 . The top end  30  of the housing  24  is formed from a conventional flap-type closure and the bottom end of the housing is formed from tapered edges  32  on flaps  34 , and an arcuate section  36  extending over the top of a portion of the meter housing  26 . Cut-out sections  38 , defined on opposed sides proximate to the top end  30  of the housing  24 , provide handles to enable a user to carry the product container  6  when it is removed from the hopper of the spreader.  
      Reference numerals  40  and  42  designate key shaped cut-out portions defined on a cylindrical part of the meter housing  26  and are provided for locking mating keys  41  and  43  (defined on a charging plate which is a component of the meter assembly, to be discussed below) and mating keys  44  and  46  (defined on a discharge plate which is another component of the meter assembly, to be discussed below). In this manner, the charging plate and discharge plate of the meter assembly are fixedly (non-rotatably) mounted to the metering housing. A rolled lip  50  of the metering housing receives therein a side edge of a component of the metering assembly (a discharge plate, discussed in greater detail below) to prevent components of the metering assembly from dropping through the metering housing, and a flange  52 , defined by the side edge of another component of the metering assembly (a selector plate, to be discussed in greater detail below) rides below the outer surface of the rolled lip  50  of the metering housing to prevent the components within the metering housing from being displaced upwardly. Accordingly, the container housing  24  and the meter housing  26  each define cooperating structure for maintaining the metering housing in a fixed position relative to the container housing  24 , and for maintaining selected components within the metering housing in a fixed orientation relative to each other. The structure and structural relationship for retaining the metering housing in the product container will be discussed in greater detail with reference to  FIG. 5 .  
      Still referring to  FIG. 2 , a drive bushing  54  joins the metering assembly components within the metering housing through center axis openings with a bushing flange  56 , a square drive  58  carried on a drive shaft within the bushing which engages a square hole  60  defined in the center of a metering disk  70 . The drive bushing  54  further extends through a compression cup  62  and a thrust washer  64 . A retaining pin, designated by reference numeral  66 , is provided to maintain the meter assembly in its assembled state within the meter housing.  
      Still referring to  FIG. 2 , the meter assembly is defined by a plurality of components contained within the meter housing  26 . The components of the meter assembly include a charging plate  68 , a metering disk  70  having a top surface disposed beneath the charging plate, a discharge plate  72  disposed beneath a lower surface of the metering disk, and a selector plate  74  disposed beneath the discharge plate. Each of these components contiguously abuts against adjacent components. As will be discussed in greater detail herein, the components of the meter assembly operatively cooperate with each other to, among other things, control the quantity of material discharged from the spreader apparatus, control the range at which material is dispersed from the spreader, and control the angular orientation at which material is dispersed from the spreader. As will also be discussed herein, the meter assembly within the metering housing  26  is driven by the linear movement of the spreader over the terrain to be treated, said movement being transferred to the meter assembly by a drive train of a transmission system coupling a wheel of the spreader to the meter assembly when the product container  6  is mounted in its operating position in the hopper  4  of the spreader  2 .  
       FIG. 3  illustrates a side view of the product container  24  and the product bag  25  shown in  FIG. 2 . The same reference numerals have been used to designate corresponding components. Reference numeral  76  illustrates strips of retainer tape which are applied to join together the flaps  34  defining the lower, inwardly tapered, end of the product container  24 .  
       FIG. 4  schematically illustrates the product container  24  showing additional features of the invention. An adhesive material is applied between the top of the product bag  25  and the top of the product housing  24  at a location designated by reference numeral  77  to maintain the bag in an extended position relative to the product housing even after material has been discharged from the bag. In this manner, the bag will not drop onto the metering housing at the bottom of the product container and interfere with the continued discharge of product when the upper portion of the product bag has become emptied as a result of the discharge of product therefrom by gravity feed. A longitudinally extending slot  78  is defined on one side of the housing  24 , and the slot is sealed by two opposed strips of double sided transparent tape  80 . In this manner, the quantity of product remaining in the clear bag  25  inside the housing  24  can be easily determined by visual observation. The lower end of the product housing  24  is sealed by a cover  82  having a side portion  84 . The cover is retained on the housing by a sealing tape  86  which when removed, exposes the inwardly tapered flaps  34  of the meter housing  26  defined on the bottom of the product housing  24 . The cover  82  is provided to protect the meter housing and to prevent any accidental discharge of product from the product bag  25  through the meter assembly, before the product container is mounted in its operating position in the hopper of the spreader.  
       FIGS. 6A and 6B  illustrate, respectively, the product container  24  with its flaps  34  in a folded position when the cover  82  seals the bottom of the product container, and the product container  24  when the flaps  34  expand outwardly and are restrained by the tape  76  when the cover  82  is removed from the bottom of the product contairer  24  exposing the meter housing  26 .  
      Keys  40  and  42  of the meter housing  26  (see  FIG. 2 ) lock into cut-outs  88  and  90  in the flaps  34  to prevent the meter housing  26  from rotating relative to the product housing  24 . When the cover  82  is removed from the bottom of the product housing  24  by removing sealing tape  86  (see  FIG. 4 ) to permit the tapered flaps  34  of the bottom portion of the product housing  24  to expand outwardly, an opening  92  is defined between the inner surfaces of the flaps at the bottom portion of the product container  24 . The meter housing  26  then slides through the opening  92  and is locked into its fixed, non-rotatable position relative to the lower portion of product housing  24  (as shown in  FIG. 2 ) by the complementary locking mating keys and cut-outs on the meter housing, the flaps of the product housing, and the components of the meter assembly, as discussed herein.  
       FIG. 5  illustrates, in detail, the lower side portion of the product container of  FIG. 2  showing the manner in which the meter housing  26  is mounted in its operational position to the lower (discharge) end of the product housing  24 . As discussed with respect to  FIG. 2 , the lower edge of the meter housing  26  is rolled inwardly to form a lip  50 . A downwardly sloped outer edge  48  of a discharge plate  72  is received in and supported by the rolled lip  50 . An outwardly extending, horizontally oriented edge  52  of a selector plate  74  is disposed beneath the rolled lip  50  to support the meter housing  26  and to prevent displacement of the components of the meter assembly upwardly into the meter housing. The selector plate  74  is itself supported by a bushing flange  56  of a drive bushing  54 . In this manner, the meter housing  26  provides support to, and is itself supported by, components of the meter assembly housed therein.  
      Referring now to  FIGS. 7A and 7B , the metering disk  70  generally illustrated in  FIG. 2 , is shown in greater detail.  FIG. 7A  shows a top plan view of the metering disk  70  which defines a plurality of concentric rows of openings, spaced radially apart from the center of the disk which defines a square opening designated by reference numeral  94 . The square opening  94  corresponds to and is adapted to receive a square drive carried by a drive shaft extending through the bushing  54  (see  FIG. 2 ) which is coupled to a wheel of the spreader by a drive train for imparting rotary movement to the metering disk as the spreader is driven linearly over the terrain to be treated. The concentric rows of openings in the metering disk  70  are defined by openings  96  forming an innermost row, openings  98  forming an intermediate row, and openings  100  forming an outermost row. As shown in  FIG. 7A , the three concentric rows are not spaced equidistantly from each other in a radial orientation, and the size, number and configuration of the individual openings forming each different row can differ from the openings forming the other concentric rows. In the metering disk illustrated by  FIG. 7A , the openings in each of the rows are spaced equidistantly apart from adjacent openings in the same row, and the openings in each row are of the same configuration and dimension as each of the other openings in the same row. The configuration, dimension, and spacing of the individual openings and the different concentric rows, as well as the number of openings and rows in the metering disk  70 , is variable. Accordingly, the specific configuration and orientation of the openings and rows illustrated by  FIG. 7A  is not critical to the invention, and can be varied from that shown. The specific parameters of the metering disk can be pre-set for the specific material being dispensed, since the meter assembly and product container comprise a single unit.  
       FIG. 7B  is a sectional view of the metering disk  70  illustrated by  FIG. 7A . As more clearly seen, each of the openings  96 ,  98  and  100  are vertical channels defined between an upper surface of the metering disk designated by reference numeral  101 , and a lower surface of the metering disk designated by reference numeral  103 . The vertical length and volume defined by each channel is variable, and decreases as the radial distance from the center  94  of the metering disk increases. Reference numeral  102  designates the lower openings defined of the channels  96  of the inner row; reference numeral  104  designates the lower openings of the channels  98  of the intermediate row; and reference numeral  106  designates the lower openings of the channels  100  of the outer row.  
       FIG. 7C  illustrates the charging plate  68 , shown in  FIG. 2 , which is arranged above and contiguous with the top surface  101  of the metering disk  70 . The charging plate  68  is fixedly mounted relative to the rotatable metering disk  70  and includes an arcuate slot portion  108  exposing different sections of the concentric rows of the opened tops of the vertical columns  96 ,  98  and  100  on the metering disk as the metering disk rotates relative to the fixed charging plate. In this manner, granular material is gravity fed from the product bag  25  (see  FIG. 2 ) and through the opened slot portion  108  of the charging plate  68 , to sequentially fill the uncovered vertical columns  96 ,  98  and  100  in the metering disk as the metering disk rotates relative to opened slot portion  108  of the fixed charging plate. After the uncovered columns  96 ,  98  and  100  have been filled with granular material, any residual material extending from the columns  96 ,  98  and  100  above the top surface  101  of the metering disk is wiped away by the forward edge  110  of the slot  108  as the metering disk  70  rotates relative to the charging plate in the direction designated by arrow  112 . In this manner, each of the uncovered columns  96 ,  98  and  100  are filled to their maximum volume by the granular material gravity fed from the product container.  
      Filling each of the vertical columns in the metering disk to its full capacity assures that material will be sequentially metered in repeatable uniform quantities and dispersed from the spreader apparatus at uniform density over the terrain to be treated. Referring back to  FIG. 2  (also see  FIG. 5 ), a discharge plate  72 , which is configured to correspond to the shape of the lower surface  103  of the metering disk, is mounted contiguously below the lower surface of the metering disk. The discharge plate includes a cut-out section similar to the cut-out portion defined in charging plate  68 , discussed above. The discharge plate is fixedly mounted relative to the rotatable metering disk to selectively uncover the bottom openings  102 ;  104  and  106  of the vertical channels  96 ,  98  and  100  defined in the metering disk as the vertical channels rotate over the opened section of the discharge plate. The discharge plate, which is fixedly mounted relative to the rotatable metering disk, is arranged relative to the charging plate, which is also fixedly mounted relative to the rotatable metering disk, so the opened or cut-out sections of the discharge plate and charging plate are offset relative to each other. In this manner, when the tops of the vertical channels defined in the metering disk are uncovered by the cut-out section  108  in the charging plate  68  and granular material is gravity fed to fill these channels to their maximum capacity, the bottoms of these vertical channels are covered by the discharge plate to retain the material in the vertical channels until these channels are filled to their maximum capacity. Thereafter, the metering disk rotates relative to the fixedly mounted charging and discharge plates so that the tops of the filled channels are covered by the closed section of the charging plate, and the bottoms of the filled channels are moved over the cut-out portion of the discharge plate to uncover the bottoms of the filled channels to permit material to be discharged from the channels by gravity feed. The cooperating operating relationship between the charging plate, the discharge plate and the rotatable metering disk assures that a repeatable uniform volume of metered material is sequentially discharged through the metering assembly during operation of the spreader.  
      Although the preferred embodiments of the invention provide a meter disk rotatable relative to fixed charging and discharging plates, it is also possible to provide a metering system including a fixed metering disk with charging and discharge plates rotatable relative to the metering disk. However, this alternative embodiment is less desirable in that it requires two rotatable elements instead of one, thereby increasing the required number of movable components.  
      Still referring to  FIG. 2  (also see  FIG. 5 ), a selector plate  74  is fixedly mounted beneath the lower surface of the discharge plate  72 . The selector plate defines opened portions corresponding to the positions of predetermined vertical columns in the metering disk, and defines closed portions which block or cover the bottoms of other predetermined vertical columns in the metering disk. In this manner, rotation of the metering disk relative to the discharge plate, as discussed above, will not uncover the lower openings in the vertical columns of the metering disk which are blocked by the selector plate. Essentially, the selector plate overrides the discharge plate by blocking portions of the cut-out section of the discharge plate through which material from columns in the metering disk would otherwise be discharged. By selectively blocking certain vertical columns of the metering disk, and by allowing material to be discharged from other vertical columns of the metering disk through the discharge plate, the selector plate controls the position on which the discharged material is deposited, by gravity feed, onto a rotatable disperser impeller of the spreader apparatus disposed beneath the selector plate.  
      The position on which material from the metering disk is deposited on the rotatable impeller controls the distance or range from which the material is propelled from the spreader by the spinning impeller. If the selector plate  74  is arranged to block discharge of material from the outer concentric row of columns  100  of the metering disk (See  FIGS. 7A and 7B ), material will be deposited closer to the center of the spinning impeller, thereby decreasing the range which the material is propelled from the impeller by applied rotational forces. On the contrary, if the inner concentric rows of columns  96  and/or  98  of the metering disk (See  FIGS. 7A and 7B ) are covered by the selector plate, material will be deposited closer to the periphery of the spinning impeller, thereby increasing the distance which the deposited material is propelled from the spinning impeller as a result of rotational forces applied thereon. Additionally, the selector plate can be arranged to block the discharge of material from different sections of the metering disk to control the angular orientation relative to the spreader apparatus at which material is propelled by the spinning impeller. Therefore, in accordance with the preferred embodiments of the present invention, the selector plate  74  cooperates with the metering disk and discharge plate to selectively control the distance and/or angular orientation at which material is discharged from the spreader and applied to the terrain being treated.  
      As discussed with respect to  FIG. 1 , the spreader  2  includes an impeller assembly  10  disposed beneath the product container  6  and the metering housing defined at the bottom of the product container. The impeller assembly includes a rotatable impeller positioned to receive material discharged by gravity feed from the metering housing and deposited on the upper surface of the impeller. The material deposited on the rotating impeller is propelled from the impeller and discharged from the spreader as a result of rotational forces applied to the deposited material.  FIG. 1  generally illustrates a belt drive  12  which mechanically couples a wheel  14  of the spreader to the impeller assembly  10  to impart rotational motion to the impeller as the spreader moves linearly along the terrain  16 .  
       FIG. 8A  illustrates the components of the impeller assembly which include a rotatable impeller comprising a disk designated by reference numeral  114  having a central hub portion designated by reference numeral  116  which is rotatable about a central axis designated by reference numeral  118 . A drive belt  120  (which is part of the belt drive  12  of  FIG. 1 ) engages the outer periphery of the central hub  116  to impart rotational movement to the impeller  114 . As the spreader  2  is moved along the terrain  16  and the wheels  14  are rotated, rotational movement proportional to the linear speed of the spreader is imparted to the disk  114  by the belt drive  12 .  
      As discussed herein, the metering assembly of the product container removably received in the hopper of the spreader includes means for controlling the position on which material from the product container is deposited, by gravity feed, onto the impeller. In this manner, the range or distance at which material is propelled by the impeller is controlled—the range increases as the material is deposited closer to the periphery of the impeller, and the range decreases as material is deposited closer to the center of the impeller. In addition to the position at which material is deposited on the impeller, the rotational speed of the impeller is another parameter which affects the range or distance at which material is propelled from the spreader—increasing the rotational speed increases the distance material is propelled, and decreasing the rotational speed decreases the distance at which material is propelled from the spreader. In accordance with the preferred embodiments of the present invention, means are provided for maintaining the rotational speed of the impeller  114  at a predetermined constant value independent of variations in the linear speed at which the spreader moves along the ground.  
      Referring back to  FIGS. 8A and 8B , two opposed weights  122  are coupled to the central hub  116  of the impeller  114  by springs  124 . The weights  122  are movable in a radial direction away from the hub  116  against the resilient force applied by the springs  124 , and are movable in a radial direction towards the central hub  116  by the resilient force applied in that direction by the springs  124 . The weights  122  are movable in grooves or guide elements  126  provided on the impeller. The weight and spring characteristics are selected to maintain the rotational speed of the impeller  114  at a preselected value. If, for example, the spreader  2  is driven at a linear speed which would cause the impeller  114  to rotate above the preselected rotational speed, the weights  122  move radially outwardly towards the periphery of the impeller against the resilient forces of the springs  124 , as a result of inertial forces applied on the weights, thereby decreasing the rotational speed of the impeller. On the contrary, if the linear speed of the spreader imparts a rotational speed to the impeller  114  below the predetermined value, inertial forces cause the weights  122  to be displaced inwardly towards the central hub  116  at the urging of the resilient forces applied by the springs  124 , to increase the rotational speed of the impeller to the predetermined value. Accordingly, the weights  122  oscillate relative to the central hub of the impeller to adjust and maintain the rotational speed of the impeller  114  at a predetermined value which is independent of changes in the linear speed of the spreader. The fixed predetermined rotational speed of the impeller is adjustable by varying the mass of the weight  122 , the resilient force exerted by the springs  124  on the weights  122 , or both. Increasing the fixed rotational speed of the impeller will increase the range at which material is propelled therefrom, and decreasing the fixed rotational speed of the impeller will decrease the range at which material is propelled therefrom.  
      Although the rotational speed of the impeller  114  of the impeller assembly  10  of the spreader  2  is adjustably set at a constant predetermined value to maintain a constant range at which material is impelled from the spreader, the metering assembly in the metering housing  26  (as previously discussed herein with respect to  FIGS. 2-7C ), is coupled to one wheel of the spreader  2  so that material is metered in proportion to the linear speed at which the spreader  2  is moved along the ground  16  (See  FIG. 1 ). A transmission system coupled to a wheel  14  of the spreader imparts rotational movement to the metering disk  70  in direct proportion to the linear speed of the spreader  2 . In this manner, the rate at which material is metered through the metering disk and deposited onto the impeller is proportional to the linear speed of the spreader so that the density of material dispersed over the terrain travelled by the spreader remains constant. In the preferred embodiments of the invention, the rotational movement of the wheel  14  is imparted to the metering assembly  26  in the product container  6  (See  FIG. 1 ) by a transmission system including a rotatable drive shaft extending through the drive bushing  54  of the metering housing  26  (See  FIG. 2 ), and a square drive carried by the drive shaft and received in the square central opening of the rotatable metering disk.  
      Therefore, the spreader in accordance with the present invention, as discussed herein, includes both means for dispersing material at a uniform density over the terrain to be treated, and means for maintaining a constant range at which the material is dispersed by the spreader independent of the linear speed at which the spreader moves along the terrain being treated. Both the metering means and the dispersing means are driven by the linear movement of the spreader along the terrain to be treated.  
       FIGS. 9-10  illustrate the transmission system for the spreader  2 , and in particular a one way spring clutch, in accordance with the preferred embodiments of the present invention. Referring first to  FIGS. 9A-9D , a wheel  132  having an outer surface  134  (corresponding to wheel  14  generally illustrated by  FIG. 1 ), has a drive plate  128  fixedly mounted to a central rim  130  by screws  136 . The drive plate  128  defines a plurality of saw teeth  138  arranged in a circular row. The drive plate  128  also defines a center axis  140  and a bushing  142  for receiving a bearing shaft  144  extending from a hub  146  of a driven plate  148 . A pin  154  secures the shaft  144  to the hub  146  so that the shaft  144  rotates together with the driven plate  148 . The driven plate  148  defines a spring plate  150  on the forward surface thereof, and a plurality of spring tabs  164  extend outwardly from the plate  150 . Shaft  144  is received in the bushing  142  of the drive plate  128 , and is secured thereto by a rib  158  defined on an end cap  160  which is received in a groove  156  of the shaft  144  after the shaft extends through the center axis  140  of the drive plate  128 . The end plate  160  is further secured to the remote end of the shaft  156  extending through the center axis  140  by a screw  162  received through aligned openings in the rib  158  on the end cap  160  and in the slot  156  of the remote end of the shaft  144 . Because the drive plate  128  is fixedly mounted to the rim  130  of the wheel  132  by screws  136 , the drive plate is rotatable together with the wheel.  
      As more clearly seen in  FIG. 9C , the saw teeth  138  defined on the drive plate  128  each include a sloped portion designated by reference numeral  166  and a perpendicular end portion designated by reference numeral  168 . The free forward ends of the spring tabs  164 , extending from the spring plate  150 , are engaged by the saw teeth  138  when the driven plate  148  is mounted to the drive plate  128  such that the spring plate  150  is in continguous engagement against the drive plate  128 . When the wheel  132  is rotated in a predetermined drive direction (i.e., the direction of rotation of the wheel  132  when the spreader is moved in a forward linear direction) as illustrated by  FIG. 9C , the perpendicular rear ends  168  of the saw teeth  138  engage the free forward ends of spring tabs  164  and impart the rotational movement of the wheel  132  to cause the spring plate  150  to rotate together with the wheel. However, when the wheel is rotated in a reverse direction, the free forward end of the spring tabs  164  move in a direction relative to the saw teeth  138  to slide up the inclined sections  166  thereof, and do not engage the perpendicular end sections  168 . Accordingly, the drive plate  128  does not engage the spring plate  150  in this reverse direction of rotation, and the rotational movement of the wheel  132  is not imparted to the spring plate  150 , thereby creating a slip or clutch condition. Therefore, rotational movement of the wheel  132  in a forward direction imparts rotational motion to the spring plate  150 , while rotational movement of the wheel  132  in the opposed direction will not impart rotational motion to the spring plate  150 .  
       FIG. 10  is a front elevational view of the spreader  2  shown in  FIG. 1 , with the product container  6  mounted thereon.  FIG. 10  further illustrates the spring plate  150  and the wheel  132 , as shown in  FIGS. 9A-9D , assembled in operational position. The same reference numerals have been used in  FIG. 10  to designate corresponding elements illustrated in  FIGS. 9A-9D .  
      When the spreader is linearly moved along the ground  16  in a forward direction, the drive plate  128  rotatable with the wheel  132  engages the driven plate  148 , transferring rotational movement to the driven plate and causing the shaft  144  fixedly mounted to the driven plate to rotate at a speed corresponding to the rotational speed of the wheel. The rotational movement of shaft  144  is transferred, through a drive train in the transmission system of the spreader, to a vertical drive shaft, designated generally by the reference numeral  170 , which is received within the drive bushing  54  of the meter housing  26  provided at the lower end of the product container  24  removably mounted to the hopper of the spreader. (See also FIGS.  1  and  2 .) As discussed herein, the metering disk of the metering assembly is rotatable at a speed proportional to the linear speed of the spreader to assure that the product dispersed by the spreader is applied to the terrain to be treated at uniform density. The impeller assembly of the spreader is separately driven by a belt drive coupled to a rotating wheel. Accordingly, when the spreader device is driven in a forward direction and the transmission system coupling the meter assembly to a rotating wheel is engaged, material is deposited on the spinning impeller by gravity feed from the metering disk, and is dispersed from the impeller by rotational forces applied to the deposited material. However, when the spreader is moved in a reverse direction and the clutch system described herein prevents the rotational movement of the wheel from being transmitted to the metering system, no material is is deposited on the impeller from the metering disk. Accordingly, although the impeller continues to rotate as a result of its independent coupling to the rotating wheel by the drive belt, no material will be deposited on the impeller, and thus no material will be discharged from the spreader. Additionally, the on/off switch  22  on the handle  20  of the spreader device (See  FIG. 1 ) disengages the meter assembly and prevents material from being discharged from the spreader apparatus, at the selection of the user, when the spreader is moved in a forward direction. Therefore, the spreader in accordance with the preferred embodiments of the invention automatically prevents material from being dispensed therefrom when it is driven in a reverse direction, but includes means to permit the user to selectively prevent material from being dispersed therefrom when it is driven in a forward direction.  
       FIGS. 11-20  illustrate a further embodiment of a dispersing apparatus, and a product container, in accordance with the present invention. Common elements illustrated by  FIGS. 11-20  will be designated by the same reference numerals used to designate the same elements in  FIGS. 1-10 . Except as otherwise indicated in the following discussion of  FIGS. 11-20 , the metering, drive train, and control systems discussed with respect to  FIGS. 1-10  are applicable to the embodiments of the invention illustrated by  FIGS. 11-20 .  
      The spreader apparatus  2  includes a hopper  4  for removably receiving a product container  6 . The lower portion of the product container includes a metering assembly, generally designated by reference numeral  170 , for controlling the flow of material by gravity feed through a bottom discharge outlet, generally designated by reference numeral  172 , of the product container  6 . A rotatable impeller  10  is disposed beneath the container discharge outlet  172  for receiving and dispersing product deposited thereon by the metering assembly, in accordance with the general operation of the granular spreader previously described with respect to  FIGS. 1-10 . As also discussed with respect to  FIGS. 1-10 , at least one of the wheels  14  is coupled by a drive train to the impeller  10  for rotating the impeller as the spreader apparatus traverses the terrain to be treated, and a clutch system designated by reference numeral  174  is provided to enable the operator of the apparatus to selectively disengage the wheels  14  from the drive train.  
      In accordance with a first improvement of the spreader apparatus illustrated by  FIGS. 11-19 , a clutch housing  176  enclosing a clutch  174  has a beveled outer edge  178  which is oriented in a direction facing the inner surface of the wheel  14 . In this manner, noise generated by the clutch as the spreader apparatus travels over the terrain to be treated is reduced and muffled by reflecting sound waves towards the inner surface of the wheel  14  for promoting quieter operation of the apparatus.  
      In a further improvement of the spreader apparatus, the drive train coupling one of the wheels  14  to the impeller  10  includes a drive belt  180  with sprocket openings  182  which engage drive pins  184  of a capstan  186 . The drive belt with openings provides a positive drive force which is superior to an O-ring belt design.  
      The broadcast spreader illustrated by  FIGS. 11-19  includes an overriding clutch designated by reference numeral  188 . The overriding clutch is disposed in the drive train coupling one of the wheels  14  to the rotatable impeller  10 . The overriding clutch, which is operatively associated with the drive belt  180 , permits the impeller  10  to continue to rotate, for a limited period of time, after the wheels  14  stop rotating. In this manner, the impeller continues to rotate even after the spreader apparatus has come to a halt for dispersing any residual material remaining on the impeller  10  after the apparatus has ceased movement. The removal of residual material assures that the proper quantity of material metered from the product container will be deposited on, and dispersed by, the impeller  10  when movement of the spreader over the terrain to be treated resumes.  
      In a further improvement of the spreader apparatus illustrated by  FIGS. 11-19 , means are provided by which the operator can selectively adjust the rotational speed ratio of the impeller relative to the rotational speed of the wheels  14  between two or more predetermined speed ratios. In this manner, the operator can select the rotational speed of the impeller, which is proportional to the range at which material deposited on the impeller is propelled therefrom. The speed ratio of the impeller is controlled by a switch located proximate to the top of a handle  20  of the spreader. The switch, generally designated by reference numeral  190 , is formed from a selector plate  192  having a tab  194  extending therefrom. The selector plate defines at least two slots  196 , each of which correspond to a different one of a plurality of predetermined rotational speeds of the impeller  10 . As illustrated by  FIGS. 11 and 13 , an on/off selector lever  198  includes a portion  200  received in one of the slots  196  of the selector plate  192 . As best shown by  FIGS. 14 and 17 - 18  of the drawings, a cable  202  is coupled between the on/off lever  198  and a pivot  204  of a toggle  206  for controlling the position of a lifting fork  208  (See  FIG. 16 ). Accordingly, movement of the on/off lever  198  between a first position in which segment  200  is received in one of the grooves  196  of the selector plate  192 , and a second position in which the on/off lever  198  is manually pivoted by the operator such that segment  200  is removed from the groove  196  of the selector plate  192 , causes the cable  202  to disengage a spring loaded hub drive  210  from the drive train coupling the wheels  14  to the rotatable impeller  10  for disengaging the drive train. Accordingly, the drive train coupling the wheels  14  to the impeller  10  will automatically disengage each time the on/off lever  198  is pivoted out of one of the grooves  196  in the selector plate  192 .  
      When segment  200  of the on/off lever  198  is received within one of the grooves  196  in the selector plate  192 , the segment  200  prevents rotational movement of the selector plate  192 . However, when the on/off lever  198  is pivoted out of groove  196 , the selector plate  192  can be rotated by movement of the tab  194  for aligning segment  200  of the on/off lever  198  with another of the grooves  196  in the selector plate  192 . The selector plate  192  is coupled by a cable  212  to a hole  214  in a crank  216  which engages a pin  218  in a horizontally movable extension bar  220  ( FIG. 14 ), horizontal movement of the extension bar  220  resulting from actuation of the cable  212  caused by movement of the selector plate  192  enables movement and engagement of a pin drive  222  with a hub drive  224  for selectively controlling the ratio of rotational speed of the impeller  10  relative to the rotational speed of the wheels  14 . This in turn controls the rotational speed of the impeller for controlling the distance which material is propelled therefrom. The selective horizontal movement of the pin drive  222  relative to the hub drive  224  is accomplished by movement of a selector fork  226  of the horizontal bar  220  through a slot  228  of the pin drive  222 .  
      The crank  216  is coupled to the horizontally sliding bar  220  through a slot  230 , as best shown in  FIG. 14 . The pin drive  222  employs a fluted spline  232  that engages and slides within a mating spline  234  of a drive bushing  236 , as illustrated by  FIG. 12 . As shown by  FIG. 14 , the selector fork  226  of the horizontal bar  220  slides within a bracket  221  mounted to a bridge  223  of the housing of the spreader apparatus.  
      It is apparent from the above description that the on/off lever  198  is operatively associated with the selector plate  192  to assure that the rotational speed of the impeller cannot be switched from one predetermined speed to another unless the drive train coupling the wheels  14  to the impeller is disengaged. This occurs because the selector switch  192  can be moved by the tab  1194  only when the on/off lever  198  is pivoted out of one of the slots  196 . However, by pivoting the lever  198  out of any slot  196 , the drive train coupling the impeller  10  to the wheel  14  is disengaged by the cable  212 . Rotation of the selector plate  192  into a position in which the lever  198  is aligned with a different slot  196  causes horizontal movement of the drive pin  222  for selectively adusting the rotational speed ratio of the impeller. The position of each slot  196  on the selector plate  192  corresponds to a different predetermined rotational speed ratio of the impeller. When the slot  196  corresponding to the predetermined speed ratio desired by the operator is aligned with the position of the on/off lever  198 , the lever is pivoted so that segment  200  is received in the slot  196 . Pivoting the lever  198  into any slot  196  re-engages the drive train coupling the wheels  14  to the rotatable impeller  10 . Thus, the selector switch  192  for controlling the rotational speed of the impeller operatively cooperates with the on/off lever  198  so that the rotational speed of the impeller can be selectively adjusted by the operator only when the drive train coupling the wheels  14  to the impeller is disengaged. Although  FIGS. 11-19  illustrate two slots  196  on the selector plate  192  corresponding to two different predetermined rotational speeds of the impeller, it is within the scope of the present invention to provide more than two slots  196  corresponding to more than two different preselected rotational speeds of the impeller.  
      In a further improvement of the spreader apparatus illustrated by  FIGS. 11-19 , a generally rectangular plate  238  is carried by the handle  20 . The plate includes a plurality of openings or stop positions designated by reference numeral  240 , and a visual indication  242  associated with each position  240 . A lever  244  has a handle  246  to permit the operator to vertically move the lever along the panel  238  between different stop positions  240 . As will be discussed below, movement of the lever  244  into the different stop positions  240  permits the operator to selectively control the orientation at which material will be propelled from the impeller  10  relative to the direction in which the spreader apparatus moves along the terrain to be treated. The visual indicia  242  provide the operator with illustrations of the spread pattern for each of the different stop positions  240 . (See  FIGS. 11, 13  and  15 ).  
      Referring now to  FIG. 15 , when handle  246  is vertically moved along a support shaft  248 , a pulley  250 , which is coupled to the movable handle  246  (and the attached lever  244 ), adjusts the length of a selector cable  252 . The selector cable  252  is attached to an adjustment screw  254 , and the selector cable is looped around the pulley  250  down to an idler pulley  256 , and then up to a selector cable take-up  258 . The selector cable  252  is then looped around a second idler pulley  260 , and up to the selector cable take-up  258 . When the handle  246  is moved into different stop positions  240 , the length of the selector cable is adjusted, thereby rotating a selector drum  262  which is operatively associated with the selector cable  252 . The selector drum  262  is rotated into a position in which material will be propelled from the impeller  10  of the spreader apparatus in the orientation illustrated by the visual indicia  242  corresponding to the position  240  in which the lever  244  is received. (As discussed with respect to  FIGS. 1-10 , the selector plate associated with the selector drum blocks preselected openings in the metering disk to control the position at which metered product is deposited on the impeller to control the distribution pattern). When the lever is moved into the lowermost vertical position designated by “OFF”, the selector drum  262  is moved into a position in which the associated selector plate completely blocks all openings in the meter disk to prevent any material from being deposited by gravity feed on the impeller  10 . Therefore, the lever  244 , which is readily accessible to the operator of the device, permits the operator to selectively control the distribution pattern of material propelled from the spreader apparatus as it moves along the terrain to be treated.  
      As illustrated by  FIGS. 11, 13  and  19 , a pair of counter-balanced elements  264  are mounted in the selector drum  262  by axle pivot shafts  266 . The rotatable counter-balance elements  264  are oriented at a 45° angle when equilibrium is achieved as illustrated by  FIG. 19 . When the product container  6  is mounted to the spreader apparatus, the counter-balance elements are rotatable in a horizontal plane. The operator moves lever  244  from the “OFF” position (the lowermost vertical position as shown by  FIGS. 11 and 13 ) to the fully opened position (the highest vertical position as shown by  FIGS. 11 and 13 ) and then back into the “OFF” position. This causes the selector drum  262  to rotate, and the counter-balance elements  264  pass under a raised rib  268  of the selector plate. The counter-balance elements  264  then rotate about the axial pivot shafts  266  for locking the counter-balance elements  264  between the raised ribs  268  of the selector plate. In this manner, the selector plate is guided into and locked into a proper operating position in which vertical movement of the handle  244  between the different stop positions  240  will result in the proper orientation of the selector plate relative to the metering assembly for propelling material from the spreader apparatus in the desired orientation corresponding to the position  240  of the lever  244 .  
      In a further improvement of the spreader apparatus illustrated by  FIGS. 11-19 , hinged flaps, designated by reference numeral  270 , are mounted to the opposed sides of the spreader chassis  272  (See  FIGS. 11-14  and  16 ). The hinged flaps  270  are provided for preventing product from drifting into undesired areas of terrain when an edge application is required. The hinged flaps are removably held in an upright position by suitable means, as for example complementary magnets  274  carried by the hinged flap and magnets  276  mounted to the side of the chassis of the spreader apparatus. When lowered, the hinged flaps  270  pivot about a hinge  278  until magnet  274  carried by the flap is magnetically coupled to magnet  280  carried on a support bracket  282  at a lower elevation on the frame of the chassis than magnet  276 . The operator may therefore selectively adjust the position of the flaps between an upright position and a lowered position for controlling the pattern of material dispersed from the rotatable impeller as the spreader apparatus moves along the terrain to be treated. When the hinged flaps are in the upright position, the upper portion of the stream of material propelled from the impeller is blocked. Although the releasable locking means used to maintain the hinged flaps in its upper and lower positions are shown as magnets, other suitable locking means can be appropriately employed.  
      The meter assembly  170  at the lower discharge outlet of the container  6  includes a spherically or dome shaped partition element  284  (See  FIGS. 11-13  and  17 - 18 ). This partition is threaded to a portion of a center stem  286 . A slot  288  is defined in the partition element  284 . The function of the partition element is to prevent the application of the full weight of the product in product container  6  onto the metering assembly  170 . The partition element is designed to carry up to 80% of the weight of the product in the product container so that only the weight of the product below the partition element  284  is applied directly to the meter assembly at any given time. The partition element  284 , in addition to diffusing the weight of the product in the product container, also serves to dissipate lumps of product into more freely flowing granular material. The partition element  284  is rotatable together with a metering disk  290  to permit product from the product container to flow through the slot  288  to maintain the rate of feed of product through the partition element  284  and onto the metering disk  290 . As the partition element  284  rotates relative to the product in the container above the partition element, the rotating slot  288  tends to break up lumps of material into smaller granular material to be metered through the metering assembly and deposited onto the impeller  10 . The length of the square on the meter drive shaft  292  is designed to be of sufficient size to accommodate four (4) tapered spiral flutes  294  on the center step  286  for guiding and piloting the square drive meter shaft  292  into the square hole  296 . In this manner, the meter assembly  170  carried at the discharge end of the product container  6  is easily coupled to the drive train of the spreader apparatus when the product container  6  is removably mounted to the spreader apparatus.  
       FIGS. 11 and 17 - 18  illustrate the product container  6  in position when removably mounted to the spreader apparatus.  FIG. 20   b  is an elevational view of the product container removed from the spreader apparatus, and  FIG. 20   a  is a bottom plan view of the container illustrated by  FIG. 20   b . The container is formed from a molded plastic and is intended to be refillable and reusable for different treatment applications. The container includes a removable lid  300  at one end and a tapered section  302  at the other end which merges into a cylindrical section  304  (See  FIG. 13 ). When the container is received in its inverted operating position in the hopper as illustrated, for example by  FIG. 13 , the removable lid  300  is oriented at the top of the inverted container and accessible to the operator for refilling the container with product without removing the container from the hopper. A rolled lip section  306 , extending from section  304 , supports the metering assembly in the bottom discharge end of the product container (See  FIG. 12 ). A selector disk flange  308  of a selector disk of the meter assembly, rides the outside portion of the lip  306  of the product container, while a flange  310  of the meter disk is supported by the inside of the rolled lip  306  so that the rolled lip  306  is sandwiched between flanges  308  and  310  (See  FIG. 12 ). Accordingly, the meter assembly is supported by the lower portion of the product container  6 , but is also prevented from moving upwardly into the product container. The metering disk is removable from the product container so that it is replaceable by a different metering disk, at the selection of the operator, to accommodate the specific requirements (e.g., density, size of granules, moisture content) of the specific product in the container to be metered by the device.  
      The broadcast spreader described herein is particularly adapted for dispensing agricultural treatment material such as pesticides, herbicides, fungicides, and fertilizer as the apparatus is driven over the terrain to be treated. However, the spreader apparatus in accordance with the present invention is useful for applications of other than agricultural materials, as for example, for spreading salt or other anti-skid or ice-melting granular materials on frozen or icy surfaces, an aquatic spreader for dispersing materials including pesticides on the surface of lakes or other bodies of water, and for industrial uses including dispersing of pellets or other granular materials to be incorporated into an article of manufacture such as a mat. Further applications of the granular spreader disclosed herein will become apparent to those skilled in the art.  
      Other modifications and advantages of the spreader within the scope of the present invention will become apparent to those skilled in the art. Accordingly, the discussion of the preferred embodiments herein are intended to be illustrative only, and not restrictive of the scope of the invention, that scope being defined by the following claims and all equivalents thereto.