Abstract:
A baler for forming crop bales and releasing or dropping the bales at targeted drop locations in a field includes a bale-forming chamber, a bale carrier rearward of the bale forming chamber, a geographic location sensor, and a control system. The bale-forming chamber forms the bales and the bale carrier supports at least one crop bale thereon and releases the bale therefrom when actuated. The geographic location sensor outputs signals corresponding with a geographic location of the baler. The control system has a plurality of targeted bale drop locations stored therein, and is configured to calculate a distance from the current baler position to a first targeted drop position and calculate a distance from the current baler position to a second targeted drop position and compare the distances to determine a desired drop location to generate a signal to command the bale carrier to release the crop bale therefrom.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/692,036, entitled SYSTEM FOR OPTIMIZING BALE DROP LOCATIONS WITHIN A FIELD filed Aug. 22, 2012, which is hereby incorporated by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Technical Field 
         [0003]    The present disclosure is generally related to agricultural balers and, more particularly, to a baler having a system for optimizing bale drop locations within a field. 
         [0004]    2. Background 
         [0005]    A baler travels or is towed through an agricultural field to gather crops and processes these crops to make bales. When a bale is formed, it may be automatically dropped in the field directly following completion thereof or commanded to be dropped therefrom by an operator of the baler at a time and location of the operator&#39;s choosing. Operators often desire to pick when and where to drop a bale to facilitate later retrieval of the bale, but manually determining the time and place to drop a bale creates extra workload on the operator and may not result in the optimum drop location. 
         [0006]    Therefore, there is a need for an improved method and apparatus for determining when and where to drop bales in a field. 
       Overview of the Invention 
       [0007]    Embodiments of the present invention solve the above-mentioned problems and provide a distinct advance in the art of crop bailing. A baler for forming crop bales may include a bale-forming chamber, a bale carrier rearward of the bale forming chamber, a geographic location sensor, and a control system. The bale-forming chamber may gather and form the crop bales and the bale carrier may support at least one crop bale thereon and release the crop bale therefrom when actuated. The geographic location sensor may output signals corresponding with a geographic location of the baler. The control system has a plurality of targeted bale drop locations stored therein, and is configured to calculate a distance from the current baler position to a first targeted drop position and calculate a distance from the current baler position to a second targeted drop position and compare the distances to determine a desired drop location to generate a signal to command the bale carrier to release the crop bale therefrom. 
         [0008]    Another embodiment of the invention is a method of determining bale drop locations within a field for crop bales formed with an agricultural baler. The method includes moving the baler along a route of travel through the field and flagging at least a first targeted bale drop position and a second targeted bale drop position in the field. Bales are formed within a bale-forming chamber as the baler moves along the route and transferring each formed bale to a bale carrier of the baler, the bale carrier operable to release the crop bale therefrom when actuated. The current position of the baler is calculated with a geographic location sensor configured to output signals representative of a geographic location of the baler when the bale carrier contains a formed bale. The method further includes calculating with a control system communicably coupled with at least one of the bale-forming chamber, the bale carrier, and the geographic location sensor a distance from the current baler position to the first targeted drop position and calculating a distance from the current baler position to the second targeted drop position. The control system compares the distances to determine a desired drop location and generates a signal to release the bale from the bale carrier. 
         [0009]    In an additional embodiment, the method further includes calculating an estimated location of a next completed bale based on direction of travel of the baler along the route, and calculating a minimum distance from a path between the current baler position and the estimated location of the next completed bale to the first targeted drop position, and calculating a minimum distance from the path to the second targeted drop position. The minimum distances are compared to determine the desired drop location. 
         [0010]    This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Other aspects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments and the accompanying drawing figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
         [0011]    Embodiments of the present invention are described in detail below with reference to the attached drawing figures, wherein: 
           [0012]      FIG. 1  is a schematic elevation view of a baler constructed in accordance with an embodiment of the present invention and towed by a tractor; 
           [0013]      FIG. 2  is a schematic elevation view of the baler of  FIG. 1 , illustrating a bale-forming chamber of the baler of  FIG. 1  opening to release a bale onto a bale carrier of the baler; 
           [0014]      FIG. 3  is a schematic elevation view of the baler of  FIG. 1 , illustrating the bale being carried on the bale carrier; 
           [0015]      FIG. 4  is a schematic elevation view of the baler of  FIG. 1 , illustrating the bale carrier being actuated to drop the bale therefrom; 
           [0016]      FIG. 5  is a schematic plan view of a field traveled by the baler, illustrating bales being dropped at even intervals throughout the field; 
           [0017]      FIG. 6  is a schematic plan view of the field traveled by the baler, illustrating bales being dropped at or near drop point  1  (DP 1 ) or drop point  2  (DP 2 ), according to commands by a control system of the baler; 
           [0018]      FIG. 7  is a flow chart of a method of determining when to drop a bale from the baler in accordance with one embodiment of the present invention; 
           [0019]      FIG. 8  is a flow chart of another method of determining when to drop a bale from the baler in accordance with another embodiment of the present invention; and 
           [0020]      FIG. 9  is a schematic diagram corresponding to the flow chart of  FIG. 8  and illustrating the distances calculated using the flow chart of  FIG. 8 . 
       
    
    
       [0021]    The drawing figures do not limit the present invention to the specific embodiments disclosed and described herein. The drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the invention. 
       DETAILED DESCRIPTION 
       [0022]    The following detailed description of the invention references the accompanying drawings that illustrate specific embodiments in which the invention can be practiced. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense. The scope of the present invention is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled. 
         [0023]    In this description, references to “one embodiment”, “an embodiment”, or “embodiments” mean that the feature or features being referred to are included in at least one embodiment of the technology. Separate references to “one embodiment”, “an embodiment”, or “embodiments” in this description do not necessarily refer to the same embodiment and are also not mutually exclusive unless so stated and/or except as will be readily apparent to those skilled in the art from the description. For example, a feature, structure, act, etc. described in one embodiment may also be included in other embodiments, but is not necessarily included. Thus, the present technology can include a variety of combinations and/or integrations of the embodiments described herein. 
         [0024]    A baler  10  constructed in accordance with embodiments of the present invention is illustrated in  FIGS. 1-4  and broadly includes a bale-forming chamber  12 , a bale carrier  14 , and a control system  16 . The baler  10  may further comprise a geographic location sensor  18 , such as a GPS sensor, configured to track a geographic position of the baler  10  as it travels through a field and to communicate the geographic location of the baler  10  to the control system  16 . The baler  10  may also include many conventional components of known prior art balers that are not described in detail herein. Additionally, while a round baler  10  is illustrated in the Figures, one skilled in the art will understand that this invention may also be applicable to square balers as well. The baler  10  may be towed by a tractor  20  or any tow vehicle through a field of crops. The tractor  20  may have an operator terminal  22 , and the control system  16  of the baler  10  may be communicably coupled to send and receive signals to and from the tractor&#39;s operator terminal  22 . 
         [0025]    The bale-forming chamber  12  may be any apparatus known in the art for forming a bale  24  or multiple bales out of various crops. The bale-forming chamber  12  may be coupled with a crop pickup device  26  configured for gathering the crops as the baler  10  is moved through the field and feeding the crop to the bale-forming chamber  12 . The bale-forming chamber  12  may comprise a number of actuatable elements configured for forming the bale  24 . The bale-forming chamber  12  may also comprise a rear portion  28  which is actuatable to pivot from a closed position, as in  FIG. 1 , to an open position, as in  FIG. 2 , once the bale  24  is completed. When the rear portion  28  is in the open position, the bale  24  in the bale-forming chamber  12  may slide aftward onto the bale carrier  14 . Once the bale  24  is located on the bale carrier  14 , the rear portion  28  may be pivoted back to the closed position so that another bale  24  may be formed in the bale-forming chamber  12 . 
         [0026]    The bale carrier  14  may be located at a rear of the baler  10 , aftward of the bale-forming chamber  12 , and may be configured to carry the bale  24  to be transported to a particular area of a field while a next bale is being formed and wrapped in the bale-forming chamber  12 . The bale  24  may alternatively be carried on a baler/wrapper combination or any structure that can hold the bale  24  while the next bale is being formed. The bale carrier  14  may also be configured to carry several bales at one time. The bale carrier  14  may be configured to drop or release the bale  24  or bales carried thereon, as illustrated in  FIG. 4 , according to commands by an operator and/or the control system  16 . For example, the bale carrier  14  may have a mechanically-pivoting release ramp  30  which is angled upward or substantially parallel to the ground in a first position for preventing the bale  24  from rolling off a rear end of the bale carrier  14 , as illustrated in  FIGS. 1-3 , and then is pivoted toward the ground to a second position, providing a ramp for the bale  24  to slide or roll off the rear end of the bale carrier  14 , as illustrated in  FIG. 4 . The bale carrier  14  may therefore comprise one or more actuatable components communicably coupled with the control system  16  to receive commands from the control system  16  and/or to send feedback or sensor signals to the control system  16 . For example, in some embodiments of the invention, a sensor or sensors may be located on the bale carrier  14  and may indicate to the control system  16  that the bale  24  is located on the bale carrier  14  or that the bale  24  has been dropped or released from the bale carrier  14 . 
         [0027]    The control system  16 , as illustrated in  FIG. 1 , may comprise any number and combination of controllers, circuits, integrated circuits, programmable logic devices such as programmable logic controllers (PLC) or motion programmable logic controllers (MPLC), computers, processors, microcontrollers, other electrical and computing devices, and/or other data and signal processing devices for carrying out the functions described herein, and may additionally comprise one or more memory storage devices, transmitters, receivers, and/or communication busses and ports. The control system  16  may be configured for one-way and/or two-way communication with the geographic location sensor  18 , the bale-forming chamber  12 , and/or the bale carrier  14  or various actuators and sensors thereof. The control system  16  may be configured to communicate with the other components of the baler  10  and/or the tractor  20  or tow vehicle via wireless means, such as Wi-Fi or the like, or via wired means, such as via USB cables or the like. 
         [0028]    In  FIG. 1 , the control system  16  is shown located on the baler  10 . However, in alternative embodiments of the invention, the control system  16  or portions of the control system  16  may be located on the tractor  20  or tow vehicle or otherwise remotely located from the baler  10  and configured to transmit and/or receive control signals to and from the baler&#39;s actuators and sensors. For example, various computers or processors of the control system  16  may communicate and exchange information with each other and may be located in remote locations relative to each other. Furthermore, the several processors or computing devices may each be configured to execute different steps, algorithms, subroutines, or codes described herein. 
         [0029]    The control system  16  may be configured to implement any combination of the algorithms, subroutines, or code corresponding to method steps and functions described herein. The control system  16  and computer programs described herein are merely examples of computer equipment and programs that may be used to implement the present invention and may be replaced with or supplemented with other controllers and computer programs without departing from the scope of the present invention. While certain features are described as residing in the control system  16  or its memory, the invention is not so limited, and those features may be implemented elsewhere. For example, databases accessed by the control system  16 , such as databases of fields and their associated bale drop locations, may be located remotely from the control system  16  and baler  10  without departing from the scope of the invention. 
         [0030]    In various embodiments of the invention, the control system  16  may implement a computer program and/or code segments to perform some of the functions described herein. The computer program may comprise an ordered listing of executable instructions for implementing logical functions in the control system. For example, the computer program may be a software program configured to run on any computer or processor of the tractor, tow vehicle, or baler. The computer program can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, and execute the instructions. In the context of this application, a “computer-readable medium” can be any physical means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The computer-readable medium can be, for example, but not limited to, an electronic, magnetic, optical, electro-magnetic, infrared, or semi-conductor system, apparatus, or device. More specific, although not inclusive, examples of the computer-readable medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a random access memory (RAM), a read-only memory (ROM), an erasable, programmable, read-only memory (EPROM or Flash memory), a portable compact disk read-only memory (CDROM), an optical fiber, multi-media card (MMC), reduced-size multi-media card (RS MMC), secure digital (SD) cards such as microSD or miniSD, and a subscriber identity module (SIM) card. 
         [0031]    As noted above, the control system  16  may comprise memory storage devices or other various memory elements. The memory may include one or more memory storage devices which may be integral with the control system, stand alone memory, or a combination of both. The memory may include, for example, removable and non removable memory elements such as RAM, ROM, flash, magnetic, optical, USB memory devices, MMC cards, RS MMC cards, SD cards such as microSD or miniSD, SIM cards, and/or other memory elements. Specifically, the memory may store at least a portion of the computer program or code segments described above, as well as user-specified preferences, information regarding user selections, bale drop locations, and the like. 
         [0032]    In some embodiments of the invention, the control system  16  may comprise an input port configured to receive location signals from the geographic location sensor  18 , an output port configured to send at least first and second control signals to the bale carrier  14 , and a processor configured for calculating when to output the first and second command signals based on various stored and sensed values, as later described herein. For example, the first control signal may command the bale carrier  14  to be actuated to the first position, carrying the bale  24  thereon, and the second control signal may command the bale carrier  14  to be actuated to the second position, thereby releasing the bale  24 . The control system  16  may be configured to receive information regarding a location of the baler  10  and a direction of travel of the baler  10 , which may be calculated using a successive series of readings from the geographic location sensor  18 . The control system  16  may also determine the baler&#39;s location relative to the bale drop locations. Furthermore, the control system  16  may comprise and/or interface with a user interface such as a mouse, keyboard, touch screen, or various data input ports whereby the user or tractor operator may input data directly into the control system  16  or otherwise exchange information with the control system. For example, the control system  16  may be communicably coupled with the tractor&#39;s operator terminal  22 , as illustrated in  FIG. 1 , which may include various means for the operator to communicate with the control system  16 , such as a user interface and a graphic display. 
         [0033]    The geographic location sensor  18  may include a GPS receiver or any other location-determining sensors known in the art. The geographic location sensor  18  may be configured to communicate with the control system  16  regarding the location of the baler. In some embodiments of the invention, the location may be provided to the control system  16  as geographic coordinates or may be provided relative to boundaries of the field. 
         [0034]    In use, the control system  16  of the baler may command the bale carrier  14  to drop a carried bale at a location nearest to a pre-determined or targeted drop location, based on a comparison of stored locations and current baler locations received from the geographic location sensor  18 . The targeted drop location may be pre-programmed into the control system  16 , operator-determined via the operator terminal  22 , and/or identified by the control system  16  based on pre-programmed parameters regarding what conditions are required for a suitable drop location. For example, without these drop locations, the baler may drop the bales  24  at regular intervals throughout a field  32 , as illustrated in  FIG. 5 . However, using targeted drop locations  34 ,  36 , as illustrated in  FIG. 6 , the control system  16  may determine locations at or near said drop locations  34 ,  36  to drop the bale  24 . For example, the drop locations  34 ,  36  may be located at either end of the field  32 , such that collecting the bales  24  may be easier, since the bales  24  are not as spread out throughout the field  32 . However, any locations in the field  32  may be used as drop locations without departing from the scope of the invention. Furthermore, any quantity of targeted drop locations may be selected without departing from the scope of the invention. In some embodiments of the invention, the drop location may be a particular region in which the bale  24  may be dropped. For example, the drop locations may be associated with locations at which the heading of the baler  10  and tractor  20  change (e.g., ends of the field). 
         [0035]    In some embodiments of the invention, before or during baling, an operator of the baler  10  may “flag” a targeted drop location using the geographic location sensor  18  of the baler  10 . This flagging may be accomplished by the operator pressing a button or otherwise indicating a location should be flagged when the baler  10  is at a desired drop location. Alternatively, the control system  16  may be programmed so that whenever a bale is dropped manually (by operator command in real time), the control system  16  may automatically flag the location of the baler  10  when the bale  24  is dropped. Flagging a location, as referenced herein, refers to the control system  16  saving particular geographic or GPS coordinates into the memory of the control system  16 . 
         [0036]    While making bales, the control system  16  of the baler  10  may keep track of the drop location and a current baler location. For example, the control system  16  may track the baler&#39;s movement, and if the distance between the drop location and the current baler location is getting smaller, the baler  10  may continue to carry the bale  24 . Conversely, if the distance between the drop location and the current baler location starts getting larger for a set amount of time (e.g., 1 second) and there is a bale on the bale carrier  14 , the control system  16  may command the baler  10  to drop the bale  24 . 
         [0037]    In some embodiments of the invention, there may be two or more flagged drop locations, such that the baler  10  would need to determine what dropping location is closest to the baler  10  and then determine whether to drop the bale  24  or not based on the distance increasing or decreasing from the closest drop location. A more elaborate software design programmed into the control system  16  could be used to estimate when the bale  24  in the bale-forming chamber  12  will be completed, and the control system  16  may use that information to determine the best bale drop location. For example, the control system  16  may determine or be programmed to store that the average distance traveled to form a bale is 80 yards. In some embodiments of the invention, if a bale is completed and placed on the bale carrier  14  ten yards away from a drop location X and 60 yards away from a drop location Y, and the baler  10  is traveling away from drop location X and towards drop location Y, then the baler  10  may be programmed and configured to have the bale carrier  14  drop the bale  24  immediately. However, as illustrated in  FIG. 9 , if the baler  10  is programmed to know that another bale will not be formed for another  80  yards, and that a current vector of travel is generally in a direction of drop location Y, the baler  10  may be programmed and configured to determine that the closest possible drop point will actually be drop location Y. Therefore, in this embodiment of the invention, the baler  10  will not drop the bale  24  until the distance from the baler  10  to drop location Y is increasing. 
         [0038]    In an alternative embodiment of the invention, the control system  16  of the baler  10  may be configured to automatically determine drop locations. For example, the control system  16  may be programmed to record bale drop locations on an initial pass of a given set of east-west or north-south windrows in a field. The software of the baler  10  could be programmed to then automatically set these points as drop locations, instead of manually setting drop locations. Then the east-west or north-south locations may be automatically matched as closely as possible via software of the baler. 
         [0039]    In some embodiments of the invention, the control system  16  may provide a notification to the operator (e.g., audible beeps and/or a visual symbol or cue) when one of the drop locations or the optimum drop location is reached, with or without automatically dropping the bale at this location. By not automatically dropping the bale at the drop location, but rather notifying the operator that the drop location has been reached, the control system  16  may allow the operator to control the mechanism that drops the bale and to choose whether or not to drop the bale at the identified location. 
         [0040]    The flow charts of  FIGS. 7 and 8  show the functionality and operation of exemplary implementations of the present invention in more detail. In this regard, some of the blocks of the flow chart may represent steps in a method  700  or an alternative method  800  for determining when or where to command the bale carrier to drop a bale. The blocks in the flow chart may also represent a module segment or portion of code of the computer programs of the present invention. The computer programs may comprise one or more executable instructions for implementing the specified logical function or functions. In some alternative implementations, the functions noted in the various blocks may occur out of the order depicted in  FIG. 7  or  8 . For example, two blocks shown in succession in  FIG. 7  or  8  may in fact be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order depending upon the functionality involved. 
         [0041]    As illustrated in  FIG. 7 , the method  700  may comprise a step of determining if the bale  24  is on the bale carrier  14 , as depicted in block  702 . If not, then this step  702  is repeated. Determining if the bale  24  is on the bale carrier  14  may be performed by requesting and/or receiving with the control system  16  signals from a sensor on the bale carrier  14 , as described above. Next, if the bale  24  is on the bale carrier  14 , the method may comprise the steps of calculating a distance (C 1 ) from the current baler position (B) to a first drop position (X), as depicted in block  704  and calculating a distance (D 1 ) from the current baler position (B) to a second drop position (Y), as depicted in block  706 . 
         [0042]    If the distance (C 1 ) to the first drop position is less than the distance (D 1 ) to the second drop position, as determined in block  708 , then a distance (C 2 ) from a subsequent current baler position (B) to the first drop position (X) is calculated, as depicted in block  710 . Then, if the distance (C 2 ) is greater than the distance (C 1 ), as determined in block  712 , the control system  16  commands the bale carrier  14  to drop the bale  24 , as depicted in block  714 . If the distance (C 2 ) is not greater than the distance (C 1 ), then the method may return to block  704 , recalculating the distance (C 1 ) to the first drop position (X) from a new current baler location. 
         [0043]    Returning now to block  708 , if the distance (C 1 ) to the first drop position is not less than the distance (D 1 ) to the second drop position, then a distance (D 2 ) from a subsequent current baler position (B) to the second drop position (Y) is calculated, as depicted in block  716 . Then, if the distance (D 2 ) is greater than the distance (D 1 ), as determined in block  718 , the control system  16  commands the bale carrier  14  to drop the bale  24 , as depicted in block  714 . If the distance (D 2 ) is not greater than the distance (D 1 ), then the method may return to block  704 , recalculating the distance (C 1 ) to the first drop position (X) from a new current baler location (B). 
         [0044]    Alternatively, as illustrated in  FIG. 8 , the method  800  may comprise a step of determining if the bale  24  is on the bale carrier  14 , as depicted in block  802 . If not, then this step  802  is repeated. Determining if the bale  24  is on the bale carrier may be performed by requesting and/or receiving with the control system  16  signals from a sensor on the bale carrier  14 , as described above. Next, the method  800  may comprise the steps of calculating a distance (C CUR ) from the current baler position (B) to a first drop position (X), as depicted in block  804  and calculating a distance (D CUR ) from the current baler position (B) to a second drop position (Y), as depicted in block  806  and illustrated in  FIG. 9 . The method  800  may also comprise the steps of calculating an estimated location (B N ) of a next completed bale, as depicted in block  808  and illustrated in  FIG. 9 . The estimated location (B N ) may be determined by the control system  16  using stored or sensed data. For example, a current bale growth rate (e.g., in cubic feet/minute), a current bale volume, and a desired completed bale volume may be used by the control system  16  to estimate a time until the next bale is completed. The control system  16  may then multiply a current speed of the baler and the time until the next bale is completed to calculate a predicted distance the baler  10  will travel before completing the next bale. Using the predicted distance and a current heading of the baler  10 , the estimated location (B N ) of the next completed bale  24  may be determined. 
         [0045]    Next, the method  800  may include a step of determining one or more locations of a line (L) extending between the current baler position (B) and the estimated location (B N ) of the next completed bale, as depicted in block  810 . Then, the method  800  may comprise the steps of calculating a minimum distance (C MIN ) from the line (L) to the first drop position (X), as depicted in block  812 , and calculating a minimum distance (D MIN ) from the line (L) to the second drop position (Y), as depicted in block  814  and illustrated in  FIG. 9 . Those minimum distances (C MIN , D MIN ) may then be compared to determine a best drop location. 
         [0046]    Specifically, the method  800  may comprise a step of determining if (C MIN ) is less than (D MIN ), as depicted in block  816 . If (C MIN ) is less than (D MIN ), the method  800  may then comprise the step of determining if (C CUR ) is equal to (C MIN ), as depicted in block  818 . If (C CUR ) is equal to (C MIN ), the method  800  may then comprise the step of dropping the bale, as depicted in block  820 . Specifically, the control system  16  may command the bale carrier  14  to drop the bale  24 . If (C CUR ) is not equal to (C MIN ), the method  800  may repeat, returning back to the step of calculating (C CUR ), as depicted in block  804 . 
         [0047]    Returning to block  816 , if (C MIN ) is not less than (D MIN ), then the method  800  may next comprise the step of determining if (D CUR ) is equal to (D MIN ), as depicted in block  822 . If (D CUR ) is equal to (D MIN ), the method  800  may then proceed to the step of dropping the bale, as depicted in block  820 . Again, the control system  16  may command the bale carrier  14  to drop the bale  24 . If (D CUR ) is not equal to (D MIN ), the method  800  may repeat, returning back to the step of calculating (C CUR ), as depicted in block  804 . 
         [0048]    Although the invention has been described with reference to the preferred embodiment illustrated in the attached drawing figures, it is noted that equivalents may be employed and substitutions made herein without departing from the scope of the invention as recited in the claims.