Abstract:
A seed delivery apparatus has a moving member that captures and entraps the seed from the seed meter and physically moves the seed from the meter to the lower outlet opening. In so doing, the seed engages and travels along an interior surface of the seed delivery apparatus. A seed sensor is mounted on the housing wall such that the seed passes directly in front of the sensor. The sensor has both the light emitting devices and the photo-sensitive elements on the same wall of the delivery apparatus, or on two opposed walls. The moving member prevents ambient light, dust and dirt from entering the housing and impacting the sensor output signal.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of U.S. patent application Ser. No. 12/364,010, filed Feb. 2, 2009. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to agricultural seeding machines and in particular to a seed delivery apparatus that captures seed from a seed meter and delivers the seed to a trench formed in the soil there below and which also includes a seed sensor to detect the passage of seed through the delivery apparatus. 
     BACKGROUND OF THE INVENTION 
     An agricultural seeding machine, such as a row crop planter or grain drill, places seeds at a desired depth within a plurality of parallel seed trenches formed in soil. In the case of a row crop planter, a plurality of row crop units are typically ground driven using wheels, shafts, sprockets, transfer cases, chains and the like or powered by electric or hydraulic motors. Each row crop unit has a frame which is movably coupled with a tool bar. The frame may carry a main seed hopper, herbicide hopper and insecticide hopper. If a herbicide and insecticide are used, the metering mechanisms associated with dispensing the granular product into the seed trench are relatively simple. On the other hand, the mechanisms necessary to properly meter the seeds, and dispense the seeds at predetermined relative locations within the seed trench are relatively complicated. 
     The mechanisms associated with metering and placing the seeds generally can be divided into a seed metering system and a seed placement or delivery system which are in series communication with each other. The seed metering system receives the seeds in a bulk manner from the seed hopper carried by the planter frame or by the row unit. Different types of seed metering systems may be used, such as seed plates, finger plates, seed disks, belts, etc. In the case of a seed disk metering system, a seed disk is formed with a plurality of seed cells spaced about the periphery of the disk. Seeds are moved into the seed cells with one or more seeds in each seed cell depending upon the size and configuration of the seed cell. A vacuum or positive air pressure differential may be used in conjunction with the seed disk to assist in movement of the seeds into the seed cell. The seeds are singulated and discharged sequentially at a predetermined rate to the seed placement or delivery system. 
     The most common seed delivery system may be categorized as a gravity drop system. In the case of the gravity drop system, a seed tube has an inlet end which is positioned below the seed metering system. The singulated seeds from the seed metering system merely drop into the seed tube and fall via gravitational force from a discharge end thereof into the seed trench. Monitoring systems are commonly used to monitor the operation of the planter. Such systems typically employ a seed sensor attached to each seed tube to detect the passage of seed therethrough. Seed sensors are readily available from a number of sources including the Dickey-john Corporation, an example of which is described in U.S. Pat. No. 4,555,624. As described, the photo sensor consists of one or more light emitting devices and one or more photo-sensitive elements generally mounted on opposing sides of the seed tube. A seed passing through the tube momentarily partially obscures the light falling on one or more of the photo-sensitive elements, thereby producing a momentary change in the normal, or steady state signal level output from the sensor. Various problems are associated with this arrangement that effect the accuracy of the monitoring system. One problem is the dust and dirt that are drawn into the seed tube as the planter is operated. Another problem is the degree of ambient light in the seed tube. The greater the ambient light, the harder it is to detect seeds. To counter the effects of dirt, dust, and light, the sensors have been located near the top of the seed tube, away from the lower outlet opening. This however, allows a greater opportunity for variation to occur in the path traveled by the seed after it has past the sensor, affecting the accuracy of seed spacing determinations by the monitor. 
     SUMMARY OF THE INVENTION 
     The present invention is a seed delivery apparatus that captures and entraps the seed from the seed meter and physically moves the seed from the meter to the lower outlet opening. In so doing, the seed engages and travels along an interior surface of the seed delivery apparatus. By placing the seed sensor on the housing wall, the seed passes directly in front of the sensor. The sensor preferably has both the light emitting devices and the photo-sensitive elements on the same wall of the delivery apparatus. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of a planter having the seed delivery apparatus of the present invention; 
         FIG. 2  is a side view of a row unit of the planter of  FIG. 1 ; 
         FIG. 3  is an enlarged side view of the seed delivery apparatus of the present invention; 
         FIG. 4  is a sectional view of the sensor mounted in an opening in the side wall of the delivery apparatus; 
         FIG. 5  is a graph of the sensor output signal over time; 
         FIG. 6  is a sectional view of the photo-sensitive elements of the sensor; and 
         FIG. 7  is a sectional view of an alternative embodiment with the sensor emitter and receiver mounted on opposed walls. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to  FIG. 1  an example planter or seeding machine  10  is shown containing the seed delivery apparatus of the present invention. Planter  10  includes a tool bar  12  as part of a planter frame  14 . Mounted to the tool bar are multiple planting row units  16 . Row units  16  are typically identical for a given planter but there may be differences. A row unit  16  is shown in greater detail in  FIG. 2 . The row unit  16  is provided with a central frame member  20  having a pair of upwardly extending arms  21  (not shown) at the forward end thereof. The arms  21  connect to a parallelogram linkage  22  for mounting the row unit  16  to the tool bar  12  for up and down relative movement between the unit  16  and toolbar  12  in a known manner. Seed is stored in seed hopper  24  and provided to a seed meter  26 . Seed meter  26  is of the type that uses a disk and an air pressure differential to retain seed on the disk as are well known to meter seed. Other types of meters can be used as well. Individual seeds are sequentially metered from the seed meter  26  and handed over to a seed delivery apparatus  28  for delivery of the seed to a planting furrow, or trench, formed in the soil by furrow openers  30 . Gauge wheels  32  control the depth of the furrow. Closing wheels  34  close the trench over the seed. The gauge wheels  32  are mounted to the frame member  20  by arms  36 . The toolbar and row unit are designed to be moved over the ground in a forward working direction identified by the arrow  38 . 
     The row unit  16  further includes a chemical hopper  40 , a row cleaner attachment  42  and a down force generator  44 . The row unit  16  is shown as an example of the environment in which the delivery apparatus of the present invention is used. The present invention can be used in any of a variety of planting machine types such as, but not limited to, row crop planters, grain drills, air seeders, etc. 
     With reference to  FIG. 3 , the seed delivery apparatus  28  is shown in greater detail. Delivery apparatus  28  includes a housing  48  positioned adjacent the seed disk  50  of the seed meter. The seed disk  50  is a generally flat disk with a plurality of apertures  52  adjacent the periphery of the disk. Seeds  56  are collected on the apertures from a seed pool and adhere to the disk by air pressure differential on the opposite sides of the disk  50  in a known manner. The disk may have a flat surface at the apertures  52  or have recessed seed cells surrounding the apertures  52 . The disk rotates counter-clockwise as viewed in  FIG. 3  and shown by the arrow  54 . At the top of  FIG. 3 , seeds  56  are shown adhered to the disk. 
     The seed delivery apparatus housing  48  has right and left laterally spaced opposite walls  49  and  51  and a side wall  53  extending therebetween. An upper opening  58  in the housing side wall  53  admits the seed from the seed meter into the housing. Pulleys  60 ,  62  mounted inside the housing  48  support a moving member shown as a belt  64  for rotation within the housing. One of the pulleys is a drive pulley while the other pulley is an idler pulley. The belt has a base portion  66  to engage the pulleys and elongated bristles  70  extending therefrom, The bristles are joined to the base portion at proximal, or radially inner, ends of the bristles. Distal, or radially outer, ends  74  of the bristles touch, or are close to touching, the interior surface  76  of the housing side wall  53 . A lower housing opening  78  is formed in the side wall  53  and is positioned as close to the bottom of the seed trench as possible. As shown, the lower opening  78  is near or below the soil surface  82  adjacent the trench. The housing side wall forms an exit ramp  84  at the lower opening  78 . Ramp  84  may be shorter or longer than shown and may also be curved. 
     Returning attention to the upper portion of  FIG. 3 , a loading wheel  86  is provided adjacent the upper opening  58 . The loading wheel is positioned on the opposite side of the seeds  56  from the brush  64  such that the path of the seeds on the disk brings the seeds into a nip  88  formed between the loading wheel and the distal ends  74  of the bristles  70 . The bottom surface of the loading wheel, facing the seed disk  50 , has recesses  90  formed therein. The recesses  90  receive seed agitators  92  projecting from the seed disk  50 . The moving agitators, by engagement with the recesses in the loading wheel, drive the loading wheel in a counter-clockwise rotation. 
     The seed is captured by the delivery apparatus  28  to remove the seed from the seed meter. The seed is then moved by the delivery apparatus to the seed discharge point where the seed is discharged from the housing into the seed trench. From the seed meter to the discharge, the seed is entrapped by the brush bristles and the side wall  53  of the housing. Movement of the seed from the upper opening  58  to the lower opening  78  is controlled by the delivery apparatus, thus maintaining the seed spacing relative to one another. Accelerometer  120  is attached to the housing or placed elsewhere on the row unit  16  to measure the acceleration of the delivery apparatus. Since the seed is entrapped in the brush bristles as it is moved to the lower opening, the acceleration measurement of row unit or housing will be the acceleration of the seed itself. Further details of the delivery apparatus, as well as variations in the arrangement of the delivery apparatus and the orientation of the delivery apparatus in the row unit and relative to the seed meter are shown in U.S. patent application Ser. No. 12/364,010; filed Feb. 2, 2009 and hereby incorporated by reference. 
     As shown in  FIG. 3 , the side wall  53  is divided by the upper and lower openings  58 ,  78  into two segments,  53   a  and  53   b . Segment  53   a  is between the upper and lower openings in the direction of belt travel while the segment  53   b  is between the lower and upper openings in the direction of belt travel. It is the gaps in the side wall  53  that form the upper and lower openings. It should be understood, however, that the delivery apparatus will function without the segment  53   b  of the side wall. It is only the segment  53   a  that functions together with the belt bristles to deliver the seed from the meter to the seed trench. Thus, the term “upper opening” shall be construed to mean a open area before the side wall segment  53   a  in the direction of belt travel and the term “lower opening” shall mean an open area after the side wall segment  53   a  in the direction of belt travel. The terms “right”, “left” and “side” as used in connection with the portions of the housing wall are used only to differentiate between wall portions and should not be interpreted as limiting terms. 
     A seed sensor  102  is disposed on the side wall  53   a . The seed sensor has two portions, an emitter  104  and a receiver  106 . The emitter emits electromagnetic radiation, for example, light, a portion of which is reflected back to the receiver. In a preferred embodiment of the wall  53   a  has at least a portion of which is transparent or translucent to allow the electromagnetic radiation to pass therethrough. See  FIG. 6 . Alternatively, as shown in  FIG. 4  the side wall  53   a  may have an opening therein into which the sensor lens  108  is seated so that the sensor forms a smooth continuation of the interior surface  76  of the side wall  53   a . It is important that the interior surface  76  provide a smooth surface for the seed  56  to travel along and not form in the disruptions that can damage the seed or the seed coating. 
     During operation, with the brush bristles  70  passing the sensor the majority of the radiation from the emitter  104  is absorbed in the brush bristles and not reflected back to the receiver  106 . As a result, absent a seed, the background noise received by the receiver  106  is relatively low. In contrast, when seed  56  passes the sensor the reflected electromagnetic radiation is much higher than the background noise producing a large spike in the signal. This is shown in the graph in  FIG. 5  with the large spikes  112  relative to the background noise  110 . The large signal to noise ratio is a result of the brush bristles absorbing, not reflecting, the radiation and also by the brush bristles holding the seed against the interior surface  76  of the side wall  53  such that the seeds pass immediately in front of the sensor  102 . This contrasts with a conventional seed tube which the seed may pass the sensor at any location within the interior of the seed tube. 
     The use of the moving member  64  produces other benefits in seed sensing as well. The presence of the bristles  70  within the delivery apparatus blocks light from entering the delivery apparatus through the lower opening  78 . In addition dust and other debris can not be drawn into the delivery apparatus by the vacuum used in the seed meter as commonly occurs with seed tubes used today. This allows the seed sensor to be located fairly low in the housing, close to the lower opening. However, because the seed is carried by the moving member  64  through the delivery apparatus, the spacing between adjacent seeds is controlled and maintained as the seeds are moved from the upper opening to the discharge opening. This enables the seed sensor  102  to be located anywhere along the path of the seeds between the upper and lower openings as there is no opportunity for the seed path to change with motion of the row unit. 
     The receiver  106 , as shown in  FIG. 6 , can be equipped with a plurality of photo-sensitive receiving elements  116  spaced laterally along the width of the wall  53   a . This can enable of a sensor  102  to not only detect a seed, but also to detect the lateral location of the seed within the delivery apparatus, that is, the seed position relative to the right and left walls  49 ,  51 . This lateral position information can be useful in determining a final position of the seed in the seed trench. 
     The sensor is mounted on the side wall by any of a variety of means. The sensor can be clipped to the housing, bolted thereto, secured by plastic ties, fastened into support structures formed on the housing, etc. In addition, the side wall may be made of a material, such as plastic resin, that allows the sensor to operate through the side wall, or the side wall may be formed with an opening therein into which the sensor is positioned. The term “mounted on” as used in the claims is to be broadly construed to include all of the above. 
     The moving member of the delivery system has been described as being a brush belt with bristles. In a broad sense, the bristles form an outer periphery of contiguous disjoint surfaces that engage and grip the seed. While brush bristles are the preferred embodiment, and may be natural or synthetic, other material types can be used to grip the seed such as a foam pad, expanded foam pad, mesh pad or fiber pad, etc. 
     Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.