Patent Abstract:
Seed meters, agricultural planters, and methods of planting seed are provided. Such meters, planters, and methods may include a housing defining a chamber, a seed disc rotatably coupled to the housing and at least partially positioned within the chamber with the seed disc adapted to engage a seed, and a sensor for detecting a characteristic of the seed after the seed disengages the seed disc and before the seed exits the seed meter. The sensor may be coupled to a seed chute of the seed meter and may detect a wide variety of seed characteristics such as seed position within the seed chute, seed size, and seed shape. The seed characteristic may be used to adjust operation of the seed meters, agricultural planters, and methods. In some instances, the adjustment may be manual. In other instances, the adjustment may be automatic.

Full Description:
RELATED APPLICATIONS 
     The present application claims the benefit of U.S. Provisional patent application No. 61/384,155, filed Sep. 17, 2010, the entire contents of which are incorporated herein by reference. 
    
    
     FIELD OF INVENTION 
     This invention relates generally to agricultural planters including a plurality of row units and seed meters and, more particularly, to consistent and accurate delivery of seeds to the ground. 
     BACKGROUND 
     Mechanical and vacuum seed meters are commonly used in agricultural planters in the planting of crops. A typical mechanical seed meter includes a housing and a rotating assembly within the housing having plural spaced “fingers” about its outer periphery. Each finger is adapted to receive an individual seed and hold that seed in place through mechanical spring force. Each seed is then sequentially released from its finger through an opening in a wall of the housing for the seed to exit into the seed tube where it falls, under gravity, to a furrow formed in the ground. In other mechanical meters, when seed exits the housing it is received by a belt which carries and drops the seed down the seed tube where it falls, under gravity, to the furrow. Still further, certain other types of mechanical seed meters use a rotatable drum or fluted roll instead of fingers to meter seeds. These meters also sequentially release the seed through an opening in the housing, allowing the seed to drop to the ground under the influence of gravity. 
     A typical vacuum seed meter includes a rotating seed disc having plural spaced apertures about its outer periphery. Each aperture is adapted to receive an individual seed which is maintained in position in the aperture on a first side of the seed disc by means of a vacuum applied to a second, opposed sided of the disc. Each seed is sequentially released from its aperture in the seed disc by interrupting the applied vacuum, allowing the seed to drop to the soil under the influence of gravity. 
     Vacuum seed meters have, to varying degrees, various operating limitations because of their design and the environment in which they operate. For example, a high vacuum must be maintained across the seed disc to securely maintain the seeds in position on the seed disc until they are released. The applied vacuum must be interrupted completely and very abruptly to allow for the consistent and accurate release of the individual seeds to ensure proper seed positioning and inter-seed spacing. Irregularities in seed position and inter-seed spacing result in poor plant development and reduced crop production. Once the vacuum source is removed from holding the seed to the disc it is only under the influence of gravity and friction from the disc it was recently adhered to. 
     After a seed is dropped by the mechanical or vacuum seed meter, the seed then travels to the ground down the seed tube. Any contact between the seed and the tube walls can influence seed velocity and affect inter seed spacing. Furthermore, with respect to vacuum seed meters, influence of the seed disc interface and tangential velocity of the seed at release will influence the fore and aft position of the seed traveling down the seed tube. Wide ranges in meter rotational speeds due to varying crop types and planting speeds in conjunction with a fixed vacuum removal point only broaden the magnitude of the fore and aft variance of the seed in the seed tube aforementioned above. 
     Present seed sensors are located in the seed tube, which is disposed between the seed meter and the soil, and such seed sensors may only provide feedback when the seed crosses a predetermined plane on its travel to the ground. Sensing within the seed tube introduces certain factors that can skew desired data associated with the sensed seed. For example, when the seed contacts an interior surface of the seed tube, the path of the seed is altered and may skew the desired data to be sensed by the sensor. This skewed data may result in false readings relating to, for example, inter-seed spacing, falsely counting skips or doubles, etc. Moreover, the data provided by these present seed sensors may only serve in calculating seed to seed spacing. 
     SUMMARY 
     In some examples, an apparatus, system and method are provided to facilitate more accurate placement of seeds in the soil during planting. 
     In other examples, more accurate feedback on seed meter performance is provided to allow meter settings to be changed to enhance seed placement by ensuring that the seed has an optimal, unimpeded path to the ground. 
     In further examples, an electronic control unit is provided and may receive feedback from a sensor and adjust meter settings automatically without operator input. 
     In still other examples, a sensor adapted to determine at least one seed characteristic such as, for example, a size, a shape, and/or a position of the seed is provided. Seed meter settings may be changed mechanically and/or electronically based on the seed characteristic in order to enhance seed placement. 
     In still further examples, a sensor is provided and may intercept a seed in the seed meter as it initiates travel from the seed meter to the soil. The sensor may include a plurality of sensing elements that allow a position of the seed to be calculated on a sensing plane. The plurality of sensing elements further allows for determining seed size and shape. 
     In yet other examples, a sensor is provided and includes at least on emitter and a plurality of receivers. The at least one emitter and the plurality of receivers cooperate to define a sensing plane. One coordinate location of a seed on the sensing plane may be calculated by determining which receivers are not receiving signals from the at least one emitter. Another coordinate of the seed location in the sensing plane is sensed by a distance measurement calculated by reflecting the sensing media back to at least one receiver on the same side as the at least one emitter. Another way of calculating the position is to have opposing emitters and receivers on opposing sides, with single emitters serving multiple receivers. Using this method, the location and number of receiver paths broken on each side can be triangulated and the position calculated. Yet another way of sensing the seed position is to have a perpendicular array of paired emitters and receivers on the X and Y axis. Using the signal from the blocked receivers in both the X and Y axis, the seed position can be calculated. 
     In yet further examples, seed size and shape may be determined. The seed size and shape may be deduced by how many blocked receiver paths in the array are broken in each direction, and the time it takes for the seed to pass through the sensing plane. Based on data from large samples, an algorithm may be used to determine the exact size based on an average of the length, width, and height of the seed. 
     In other examples, the information gathered in connection with the seed characteristics may be used to make manual adjustments to seed meter settings such as singulation, vacuum, and seed release point. This information may also be utilized in a closed loop control system to automatically adjust singulation, vacuum, and seed release point. 
     In further examples, a seed meter for an agricultural planter is provided and includes a housing defining a chamber, a seed disc rotatably coupled to the housing and at least partially positioned within the chamber, the seed disc is adapted to engage a seed, and a sensor for detecting a characteristic of the seed after the seed disengages the seed disc and before the seed exits the seed meter. 
     In yet other examples, an agricultural planter is provided and includes a seed meter including a housing defining a chamber, a seed disc rotatably coupled to the housing and at least partially positioned within the chamber, wherein the seed disc is adapted to be engaged by a seed, and a seed chute. The agricultural planter also including a sensor for detecting a characteristic of the seed after the seed disengages the seed disc and before the seed exits the seed meter, and a seed tube formed separately from the seed chute and at least partially aligned with the seed chute to receive the seed after the seed exits the seed chute, wherein the seed tube communicates the seed to a furrow. 
     In yet further examples, a method of planting seed with an agricultural planter is provided and includes providing a seed meter for singulating seed therefrom, the seed meter including a seed disc engageable by seed and a seed chute defining a cavity therein, providing a sensor, dispensing a first seed from the seed disc and into the cavity of the seed chute, determining a characteristic of the first seed with the sensor while the first seed is positioned within the cavity of the seed chute, communicating information associated with the characteristic of the first seed to an electronic control unit, and adjusting dispensing of a second seed from the seed meter based on the communicated information associated with the characteristic of the first seed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of an exemplary row unit of a planter, the row unit including an exemplary seed characteristic sensor; 
         FIG. 2  is side view of a portion of the row unit shown in  FIG. 1 , the illustrated portion of the row unit including an exemplary seed meter, an exemplary seed tube, and an exemplary seed characteristic sensor; 
         FIG. 3  is a cross-sectional view taken along line  3 - 3  in  FIG. 2 ; 
         FIG. 4  is a cross-sectional view taken along a similar reference plane as  FIG. 3  showing another exemplary seed characteristic sensor; 
         FIG. 5  is a cross-sectional view taken along a similar reference plane as  FIG. 3  showing a further exemplary seed characteristic sensor; 
         FIG. 6  is a cross-sectional view taken along a similar reference plane as  FIG. 3  showing yet another exemplary seed characteristic sensor; 
         FIG. 7  is a cross-sectional view taken along a similar reference plane as  FIG. 3  showing yet a further exemplary seed characteristic sensor; 
         FIG. 8  is an exemplary system diagram; 
         FIG. 9  is an exemplary image displayable on an operator interface; 
         FIG. 10  is another exemplary image displayable on an operator interface; 
         FIG. 11  is a further exemplary image displayable on an operator interface; 
         FIG. 12  is another system diagram; and 
         FIG. 13  is a cross-sectional view taken along a similar reference plane as  FIG. 3  showing still another exemplary seed characteristic sensor. 
     
    
    
     Before any independent features and embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of the construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. 
     DETAILED DESCRIPTION 
     With reference to  FIGS. 1 and 2 , an exemplary row unit  1  of an agricultural planter is illustrated. The row unit  1  may be coupled to a frame or toolbar (not shown) of a tractor by a coupling  2 . The row unit  1  includes a frame  3  coupled to the coupling  2 , a pair of flat circular disc blades  4  coupled to the frame  3  to open a seed trench or furrow in the ground, a pair of depth gauge wheels  5  coupled to the frame  3  and located adjacent to and slightly to a rear of the blades  4 , a seed meter  10  which “singulates” seed  13  from a seed hopper  6  and drops the seed  13  one at a time from the seed meter  10 , and a seed tube  11  formed separately from the seed chute  10   b , at least partially aligned with the seed chute  10   b  to receive the seed  13  after exiting the seed chute  10   b , and facilitates deposit of the seed  13  into the furrow formed by the twin disc opener blades  4 . The row unit  1  also includes a seed characteristic sensor  14  for sensing characteristics of the seed  13  and a pair of spaced apart closing wheels  7  coupled to the frame  3  and positioned to follow after the planted seed  13  for breaking down the furrow side walls on either side of the furrow and cover the seed  13 , close the furrow, and firm the soil over the covered seed  13 . The gauge wheels  5  determine, at least in part, the depth of the furrow formed by the opener blades  4 . The seed meter  10  may be any type of seed meter  10  such as, for example, a mechanical seed meter, a vacuum seed meter, etc., and be within the intended spirit and scope of the present invention. The following description and associated figures relate to a vacuum seed meter. However, such description and figures of the vacuum seed meter are not intended to be limiting upon the present invention. 
     Referring to  FIG. 2 , a portion of the row unit  1  is illustrated and includes the seed meter  10 , which is comprised of a seed disc  10   a , a seed chute  10   b , and the seed characteristic sensor  14 . Seed  13  is held to the seed disc  10   a  by a conventional vacuum source. The seed  13  then rotates to a point where the vacuum source is removed  10   c , thereby causing the seed  13  to leave the disc and enter the seed chute  10   b . As the seed  13  passes down the seed chute  10   b  of the seed meter  10 , the seed  13  is intercepted by the seed characteristic sensor  14 , which can be unitary with the seed meter  10 . After passing the seed characteristic sensor  14  and exiting the seed chute  10   b , the seed  13  then enters the seed tube  11  and is delivered to the ground  12 . The seed chute  10   b  has first and second opposing side walls  50 ,  51  and third and fourth opposing side walls  52 ,  53 , together defining a cavity  54  in the seed chute  10   b  for passage of a seed  13  from the seed meter  10  to the seed tube  11 . In one exemplary embodiment, the seed characteristic sensor  14  may be positioned adjacent an outside or exterior  55  of any of the side walls  50 - 53  of the seed chute  10   b . The seed characteristic sensor  14  detects at least one seed characteristic for each seed  13 . Such characteristics may include, for example, seed position, seed size, seed shape, etc. Positioning the seed characteristic sensor  14  adjacent to the seed chute  10   b  allows the seed characteristic sensor  14  to detect the seed characteristic before movement of the seed is affected by other factors. Such factors may include, for example, engagement of the seed with one of the side walls  50 - 53 , etc. 
     The seed characteristic sensor may be a wide variety of types of sensors such as, for example, infrared sensors, LED sensors, lasers, visible light, etc. The sensors illustrated and described herein are for exemplary purposes only and are not intended to be limiting upon the present invention. Rather, any type of sensor may be used with the present invention. 
     It should be understood that the seed characteristic sensor  14  may be coupled to the seed chute  10   b  in a variety of manners and in a variety of positions, but ultimately be able to determine at least one seed characteristic. For example, the seed characteristic sensor  14  may be clipped, bolted, fastened, tied (e.g., with plastic ties), adhered, unitarily formed with as one-piece, etc. to the seed chute  10   b . In some exemplary embodiments, one or more of the side walls  50 - 53  may be made of a transparent or translucent material to allow the seed characteristic sensor  14  to operate through the one or more side walls  50 - 53  of the seed chute  10   b  (see e.g.,  FIG. 3 ). In other exemplary embodiments, an opening may be defined in one or more of the side walls  50 - 53  and the seed characteristic sensor  14  may be at least partially aligned with and/or positioned within the opening to sense at least one seed characteristic (see e.g.,  FIG. 7 ). 
     It should also be understood that the seed sensor may be coupled to other portions of the seed meter or to other portions of the row unit  1  and be within the intended spirit and scope of the present invention. 
     With reference to  FIG. 3 , an exemplary embodiment of the seed characteristic sensor  14  is illustrated and includes a plurality of substantially coplanar emitters  14   b , a first plurality of substantially coplanar receivers  14   a , and a second plurality of substantially coplanar receivers  14   g . In some exemplary embodiments, the emitters  14   b , the receivers  14   a , and the receivers  14   g  are all substantially coplanar with each other. The emitters  14   b  and receivers  14   g  are coupled to circuit board  14   e  and the receivers  14   a  are coupled to circuit board  14   f . When the seed  13  travels down the seed chute  10   b , it breaches at least one of the beams  14   d  emitted by the emitters  14   b . The X position of the seed  13  can be calculated by determining which beams  14   d  are blocked by the seed  13 . As the seed  13  breaks one or more of the beams  14   d  emitted by the emitters  14   b , the broken beams  14   c  reflect back in the direction of the emitters  14   b . The reflected back beams  14   c  are sensed by the receivers  14   g  positioned on the same side of the chute  10   b  as the emitters  14   b . The position in the Y direction may be calculated by a measure of the time it takes for the reflected back broken beams  14   c  to be sensed by the receivers  14   g . In this illustrated exemplary embodiment, the side walls  50 - 53  of the chute  10   b  are made of a transparent or translucent material to allow the emitters  14   b  and receivers  14   a ,  14   g  to be positioned externally of the cavity  54  and operate through the side walls  50 - 53  to sense seed characteristics. By positioning the seed characteristic sensor  14  externally of the cavity  54 , the seed characteristic sensor  14  is not exposed to the environment within the cavity  54 . Exposure to such environment may negatively affect the performance of the seed characteristic sensor  14 . 
     With reference to  FIG. 4 , another exemplary embodiment of a seed characteristic sensor  26  is illustrated and the sensor  26  includes a perpendicular set of coplanar emitters  26   b  and receivers  26   a  that will calculate the seed&#39;s  13  position in the X and Y dimensions. In this illustrated exemplary embodiment, the X dimension is calculated in a similar manner to that described above in connection with  FIG. 3 . That is, the emitters  14   b  and receivers  14   a  cooperate to determine which beams  14   d  are blocked by the seed  13 . The Y dimension in this illustrated exemplary embodiment may be calculated with emitters  26   b  and receivers  26   a . The emitters  26   b  emit beams  26   d  and the receivers  26   a  are capable of receiving the beams  26   d . As the seed  13  passes through the beams  26   d , at least one of the beams  26   d  is blocked. Thus, the emitters  26   b  and receivers  26   a  cooperate to determine which beams  26   d  are blocked by the seed  13 , thereby calculating the Y dimension of the seed  13 . By determining the number of emitter beams  14   d  that are blocked, the size of the seed in the X axis can be calculated. Seed size in the Y axis may be determined by the number of emitter beams  26   d  that are blocked. The final dimension of seed size may be calculated using the time it takes the seed  13  to pass through the seed characteristic sensor&#39;s  14  sensing plane. 
     Referring now to  FIG. 5 , yet another exemplary embodiment of a seed characteristic sensor  27  is shown and includes single source emitters  27   a  and  27   b  that are located on opposite sides of the chute  10   b  and two sets of receivers  27   c  and  27   d , one set associated with each emitter  27   a  and  27   b . Each emitter  27   a  or  27   b  provides the sensing media for its respective set of receivers  27   c  and  27   d  located on the opposite side of the chute  10   b . The position of the seed  13  in both the X and Y locations can be triangulated by determining the number of receivers  27   c  and  27   d  blocked on each side of the chute  10   b.    
     Referring now to  FIG. 6 , yet another exemplary embodiment is illustrated and includes one single source emitter  27   b  and one set of receivers  27   d  for receiving emitter beams  14   d  from the emitter  27   b . The characteristics of the seed  13  such as, for example, position and size, may be determined in a similar manner to that described in connection with  FIG. 5 . 
     With reference to  FIG. 7 , openings  60 ,  62 ,  64  are defined in each of the side walls  52 ,  53 . The emitters  14   b  are positioned in openings  60  defined in side wall  52 , the receivers  14   a  are positioned in openings  62  defined in side wall  53 , and receivers  14   g  are positioned in openings  64  defined in side wall  52 . In this exemplary embodiment, the emitted beams  14   d  from the emitters  14   b  do not pass through any of the side walls  50 - 53  of the chute  10   b  due to the openings  60 ,  62 ,  64 . It should be understood that any number of the side walls  50 - 53  of the chute  10   b  may have openings defined therein for receiving emitters or receivers and be within the intended spirit and scope of the present invention. For example, the embodiment illustrated in  FIG. 7  includes openings  60 ,  62 ,  64  defined in side walls  52  and  53 . Alternatively, all four side walls  50 - 53  of the chute  10   b  may have openings defined therein to receive emitters and receivers. Such an alternative embodiment may be appropriate to accommodate an emitter and receiver configuration illustrated in  FIG. 4 . 
     Referring now to  FIG. 8 , an exemplary system or network is illustrated. Information associated with seed characteristics may be sent from the seed characteristic sensor  14  via a communication protocol  21  to a row unit electronic control unit  17 . In the illustrated exemplary embodiment, one row unit ECU  17  is associated with each row unit  1  and each seed characteristic sensor  14  communicates with its own row unit ECU  17 . A plurality of seed meters  10  including the seed characteristic sensors  14  can then be connected to a master electronic control unit  16  via a communication protocol  22 . The master ECU  16  then feeds the signal to an operator interface  15  using an implement communication bus  23 . The operator interface  15  may be a wide variety of devices capable of displaying information such as text and images to an operator. For example, the operator interface may be a display, a monitor, etc. 
       FIG. 9 ,  FIG. 10 , and  FIG. 11  relate to the feedback provided to the operator from the seed characteristic sensor  14 , through the system or network described in connection with  FIG. 8 . It should be understood that the exemplary embodiments illustrated in  FIGS. 9-11  of displayed feedback are one manner of many possible manners of displaying feedback and all such manners are intended to be within the spirit and scope of the present invention. 
       FIG. 9  shows the operator feedback for a position of the seed  13  in the seed chute  10   b . In the illustrated exemplary embodiment, the operator feedback for position  18  consists of three zones in which the seed  13  can fall through the seed chute  10   b . These three zones are green  18   c , yellow  18   b , and red  18   a . The indicator  18   d  signifies which range the seed  13  is in and is moveable between zones depending on the position of the seed  13 . Green  18   c  represents to the operator that spacing average is being optimized, while yellow  18   b  and red  18   a  signifies that adjustments might need to be made. In other embodiments of this invention other colors may be used. In still other exemplary embodiments, any number of zones having any sized increments may be used. An audio or visual warning signal may be triggered if seed spacing is not optimal or if the system is operating erratically. 
       FIG. 10  is a depiction of seed size presented to the operator on the operator interface  15 .  FIG. 10  represents the seed size  19  on the operator interface  15  which is broken into three categories large  19   a , medium  19   b , and small  19   c . The indicator  19   d  dictates to the operator where the seed  13  is in the range. This information is further used to make manual adjustments to the seed meter  10  to increase performance of the meter  10  for the size of the seed  13  being planted. It should be understood that the size characterizations and categories described above (i.e., small, medium, and large) and illustrated in  FIG. 10  are only exemplary size characterizations and categories, and the invention is capable of having different size characterizations and categories, and being within the intended spirit and scope of the present invention. It should also be understood that a depiction displayed on the operator interface  15  relating to size of the seed may include any number of categories or size characterizations and be within the intended spirit and scope of the present invention. The illustrated exemplary embodiment includes three categories or size characterizations. Other exemplary embodiments may include any number of categories or size characterizations. 
     Shape of the seed is represented by the shape output  20  on the operator interface  15  which can be seen in  FIG. 11 . In the illustrated exemplary embodiment, there are two designations for seed shape, round  20   a  and flat  20   b . The shape is communicated to the operator via the indicator  20   c . Information about seed shape will be used by the operator to make seed meter  10  adjustments to increase spacing accuracy. It should be understood that the shape designations or characterizations described above (i.e., round and flat) and illustrated in  FIG. 11  are only exemplary shape designations and characterizations and the invention is capable of having different shape designations and characterizations and be within the intended spirit and scope of the present invention. It should also be understood that a depiction displayed on the operator interface  15  relating to shape of the seed may include any number of designations or shape characterizations and be within the intended spirit and scope of the present invention. The illustrated exemplary embodiment includes two designations or shape characterizations. Other exemplary embodiments may include any number of designations or shape characterizations. 
       FIG. 12  relates to a closed loop control of adjustments based on information from the seed characteristic sensor  14  in lieu of manual adjustments. Data associated with one or more seed characteristics such as, for example, seed position, seed size, and seed shape is received by the row unit ECU  17  from the seed characteristic sensor  14  and is used by said row unit ECU  17  to determine what adjustments need to be made to the seed meter  10  to improve spacing accuracy. 
     Data associated with the one or more seed characteristics may be used to make adjustments electronically to the seed release adjustment mechanism  23  to ensure that the seed  13  is consistently being dropped as close to a middle of the seed chute  10   b  as desired. The seed release adjustment mechanism  23  may also be adjusted proportionally to implement ground speed which will be available through the main communication protocol  22 . All adjustments are made electronically and independent of the operator. 
     Some seed characteristics such as, for example, seed size and seed shape may dictate adjustments to the vacuum  24  and singulation  25 . The row unit ECU  17  may make determinations on adjustments to vacuum  24  and singulation  25  based on seed size, shape, and meter speed and adjust them electronically without input from the operator. 
     Referring now to  FIG. 13 , still another exemplary embodiment is illustrated and includes a single emitter  14   b  and a plurality of receivers  14   a  for receiving beams  14   d  emitted by the emitter  14   b . The walls  50 - 53  of the seed chute  10   b  are transparent or translucent to allow the beams  14   d  to pass through the walls  50 - 53  and be received by the receivers  14   a . As a seed  13  passes through the seed chute  10   b , the seed will block a portion of the beams  14   d , thereby indicating to the seed characteristic sensor  14  and the row unit ECU  17  a characteristic of the seed  13 . In this illustrated exemplary embodiment, the walls  50 - 53  of the seed chute  10   b  have a different configuration than the walls  50 - 53  of the seed chute  10   b  in other illustrated exemplary embodiments. In the illustrated exemplary embodiment, the opposing walls  50  and  51  are not linear, but instead are each comprised of two intersecting angled portions, thereby providing the chute  10   b  with an overall hexagonal cross-sectional shape. 
     It should be understood that while the opposing walls  50 - 53  may have a variety of shapes and configurations that may not be substantially linear and parallel with each other, the two walls  50  and  51  and the two walls  52  and  53  may remain opposing to each other on opposite sides of the cavity  54  no matter the shape and configuration of the walls  50 - 53 . 
     It should also be understood that the walls of the seed chute may have a wide variety of shapes and all of such possible shapes are intended to be within the spirit and scope of the present invention. 
     It should further be understood that the features of any of the exemplary embodiments illustrated and described herein may be incorporated into any of the other exemplary embodiments illustrated and described herein in any combination and without any limitation. 
     The foregoing description has been presented for purposes of illustration and description, and is not intended to be exhaustive or to limit the invention to the precise form disclosed. The descriptions were selected to explain the principles of the invention and their practical application to enable others skilled in the art to utilize the invention in various embodiments and various modifications as are suited to the particular use contemplated. Although particular constructions of the present invention have been shown and described, other alternative constructions will be apparent to those skilled in the art and are within the intended scope of the present invention.

Technology Classification (CPC): 0