Abstract:
A motorized chain roller includes a frame, a roller chain assembly movably disposed within the frame, a first sprocket that engages the roller chain assembly to apply a transmission force to the roller chain assembly, at least one motor coupled to the frame and configured to transmit a rotational force to the first sprocket, and a load-bearing member coupled to and located within the frame. The roller chain assembly includes a plurality of interconnected cylindrical rolls arranged in a continuous series. Each of the cylindrical rolls has an axis or rotation. The roller chain assembly engages the load-bearing member to cause movement between the roller chain assembly and the load-bearing member perpendicular to the axes of rotation.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to chain rollers or load skates that are capable of transporting heavy objects, and more particularly to motorized or self-propelled chain rollers or load skates for transporting heavy objects. 
       BACKGROUND 
       [0002]    Heavy objects must be transported in various environments, including manufacturing and repair facilities. However, transporting heavy loads is a difficult and often time consuming undertaking due to the weight of the object(s) and also often due to the bulkiness of the object(s). It is desired to transport such heavy objects as time efficiently as possible, with as little machinery as possible, and as safely as possible. To achieve those goals, it is often desired that the transporter have the lowest possible profile. 
         [0003]    Typically, a transporter for heavy objects has a tread assembly including tread segments wrapped around one or more driven gears and a number of stationary axles. The driven gear(s) and the stationary axles define the path of the tread assembly. Only the tread segments contact the ground or floor surface; neither the driven gear(s) nor the stationary rollers contact the ground or floor surface. A significant number of the tread segments contact the ground or floor surface. The tread segments are stationary relative to the ground or floor surface when they engage the ground or floor surface. 
         [0004]    A horizontal force in the direction that the transporter is to travel is applied to the transporter or a force is applied to one or more of the gears to rotate the gears in the desired direction. That force causes the transporter to move in the desired direction with the tread segments serially engaging the ground or floor surface. The engagement of the tread segments with the ground or floor surface propels the machine in the desired direction. 
         [0005]    Other heavy load transporters include chain roller assemblies that utilize a series of rollers linked together to form the track. 
       SUMMARY 
       [0006]    According to preferred embodiments of the invention, there is provided a motorized chain roller for transporting heavy loads that includes a frame, a roller chain assembly movably disposed with the frame that includes a plurality of interconnected cylindrical rolls arranged in a continuous series, a first sprocket that engages the roller chain assembly to apply a transmission force to the roller chain assembly, a motor coupled to the frame and configured to transmit a rotational force to the first sprocket, and a load-bearing member coupled to and located within the frame. In these embodiments, the roller chain assembly is configured such that the rolls engage the load-bearing member to cause movement between the roller chain assembly and the load-bearing member perpendicular to the axes of rotation. 
         [0007]    In some embodiments of the invention, the load-bearing member may be a plate. The rolls may engage one surface of the plate. 
         [0008]    In other embodiments, the motorized chain roller may include a second sprocket spaced from the first sprocket. The roller chain assembly may form a loop around the first and second sprockets. The load-bearing member may be located within the loop, between the first and second sprockets. Two motors may be used to transmit a rotational force to the two sprockets. Alternatively, one of the sprockets may be an idler sprocket. 
         [0009]    In yet other embodiments of the invention, the roller chain assembly may include a “chain” comprised of a plurality of overlapping links that connect the plurality of rolls to one another. The “chain” may include (1) a first set of links, wherein each link of this first set of links extends between and connects a pair of adjacent rolls (each link is attached to a different pair of rolls) and (2) a second set of links, wherein each link of this second set of links also extends between and connects a pair of adjacent rolls (again, each link is attached to a different pair of rolls). A pair of rolls connected to a link of the first set is never the same as a pair of rolls connected to a link of the second set. That is, a pair of rolls connected to a link of the second set always includes a roll that is also connected to one link of the first set and a roll that is also connected to a second link of the first set. The first sprocket may engage the second set of links to apply transmission force to the roller chain assembly. 
         [0010]    In further embodiments of the invention, the cylindrical rolls of the roller chain assembly may be configured to contact the ground, pavement or a floor surface and a bottom surface of the load-bearing member and propel the motorized chain roller when the roller chain assembly moves in its loop. The direction and path of the motorized chain roller may be controlled by a rail, bar, or other elongated member. At least one guide block may be provided that mates with the rail, bar, or other elongated member so that the motorized chain roller moves along a path defined by the rail, bar, or other elongated member. Alternatively, the rail, bar, or other elongated member may be part of a track that is mounted on the ground, pavement or floor surface, such that the motorized chain roller moves along and is supported by the track. 
         [0011]    Furthermore, some of the embodiments of the motorized chain rollers of this invention may have two modes of operation. In the first mode, the chain roller assembly rests of the ground, pavement or floor surface and the object to be transported in placed on the motorized chain roller. Movement of the chain roller assembly in its loop causes the motorized chain roller to move in a lateral direction perpendicular to the axes of rotation of the rolls because the rolls simultaneously engage the load-bearing surface and the ground, pavement or a floor surface. In the second orientation, the load-bearing surface of the motorized chain roller is placed on the ground, pavement or floor surface, with the chain roller assembly being exposed upward. The object(s) to be transported is placed on the chain roller assembly. Movement of the chain roller assembly in its loop causes the object(s) to be moved laterally across the top of the motorized chain roller, perpendicular to the axes of rotation of the rolls. 
         [0012]    In this manner, this invention provides a motorized chain roller assembly that is compact, is self-sufficient, has a high load carrying capacity and reduces the time and machinery necessary to transport heavy loads. 
         [0013]    Other advantages, benefits and features of the present invention will become apparent to those skilled in the art upon reading the detailed description of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a perspective view of a motorized chain roller of one embodiment of this invention. 
           [0015]      FIG. 2  is an exploded view of the motorized chain roller illustrated in  FIG. 1 . 
           [0016]      FIG. 3  is a perspective view of the roller chain assembly and the sprocket assemblies of the motorized chain roller illustrated in  FIGS. 1 and 2 . 
           [0017]      FIG. 4  is a partially exploded view of the roller chain assembly and the sprocket assemblies illustrated in  FIG. 3 . 
           [0018]      FIG. 5  is a perspective view of the roller chain assembly, the sprocket assemblies and the load-bearing member of the motorized chain roller illustrated in  FIGS. 1-4 . 
           [0019]      FIG. 6  is a side view of the motorized chain roller illustrated in  FIGS. 1-5  with selected components removed for clarity. 
           [0020]      FIG. 7  is an exploded view of the frame and the load-bearing member of the motorized chain roller illustrated in  FIGS. 1-6 . 
           [0021]      FIG. 8  is a perspective view of a motorized chain roller of a second embodiment of this invention with selected components removed for clarity. 
           [0022]      FIG. 9  is a partially exploded view of the roller chain assembly, the sprocket assemblies and the motors of the motorized chain roller illustrated in  FIG. 8 . 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0023]    Referring to the accompanying drawings, motorized chain rollers according to the invention will be described. 
         [0024]    Motorized chain roller (MCR)  1  is illustrated in  FIGS. 1-7  and includes a frame  3 , a load-bearing member  11  attached to the frame  3 , motor stacks  9  attached to the frame  3 , sprocket assemblies  7  driven by the motors of motor stacks  9  and rotatably supported by the frame  3 , a roller chain assembly  5  that engages and forms a loop around the sprocket assemblies  7 , and guide block assemblies  33  that are also attached to the frame  3 . 
         [0025]    I. The Frame 
         [0026]    In this embodiment, the frame  3  includes a top load-bearing plate  13 , two top cover plates  15 , two side plates  17 , a front plate  19 , a back plate  21  and a tension member  57 . See  FIGS. 1 ,  2  and  7 . Any combination of plates and other rigid members can be used to form the frame of other embodiments of this invention as long as the members provide the structural strength and integrity to support the heavy loads to be transported and adequately support the roller chain assembly, the sprocket assembly(ies), the motor(s) and the load-bearing member. 
         [0027]    The two side plates  17 , the front plate  19  and the back plate  21  are connected at their edges to form a basic rectangular frame. The top load-bearing plate  13  and the top cover plates  15  are attached to the top of the rectangular frame formed by the two side plates  17 , the front plate  19  and the back plate  21  and enclose the top of that rectangular frame. The side plates  17 , the front plate  19 , the back plate  21 , the top load-bearing plate  13  and the top cover plates  15  may be attached to each other by screws, bolts and nuts, pins or welding, with or without braces. 
         [0028]    The side plates  17  are parallel. In this embodiment, each side plate  17  includes apertures  23  and  27  and an indentation  28  (see  FIGS. 2 and 7 ). 
         [0029]    As discussed below, the drive shafts  25  of the motor stacks  9  are received through apertures  23  to engage sprocket assemblies  7 . Apertures  27  are provided for access to the sprocket assemblies  7  and the roller chain assembly  5 . In this embodiment, the aperture  23  in a first of the side walls  17  is opposite the aperture  27  in the other side wall  17 . Likewise, the aperture  27  in the first side wall  17  is opposite the aperture  23  in the other side wall  17 . In other embodiments, the side walls  17  may not have any apertures  27  or may have additional apertures to access the sprocket assemblies  7  and/or the roller chain assembly  5 . 
         [0030]    Closing plates  31  are removably attached to side walls  17  to cover apertures  27 . The closing plates  31  prevent exposure of the roller chain assembly  5  housed inside the frame  3 . 
         [0031]    The edges of the load-bearing member  11  are received within the indentations  28  of side walls  17 , as shown in  FIG. 7  and discussed below. 
         [0032]    In this embodiment, the top load-bearing plate  13  extends beyond the side walls  17 , but does not extend all the way between the front plate  19  and the rear plate  21 . Moreover, in this embodiment, the top load-bearing plate  13  has a rectangular shape. In other embodiments, the top load-bearing plate may be of any shape and size that can support the heavy loads to be transported without a risk of the motorized chain roller tilting if a load is not centered on the top load-bearing plate. 
         [0033]    The top load-bearing plate  13  may be made of steel or any other material with high strength that does not substantially deform under heavy loads. 
         [0034]    As stated, in this embodiment, the top load-bearing plate  13  does not extend all the way between the front plate  19  and the back plate  21 . Thus, one or more top cover plates  15  are provided to fully enclose the top opening of the rectangular frame formed by the two side plates  17 , the front plate  19  and the back plate  21 . The top cover plates  15  abut the top load-bearing plate  13  on opposite sides of the top load-bearing plate  13 . 
         [0035]    While this embodiment includes two top cover plates  15  of the same shape and size, other embodiments may not have any top cover plates or may have any number of top cover plates of the same or different shape and size. 
         [0036]    The tension member  57  is attached to the top load-bearing plate  13  and extends downwardly from the top load-bearing plate  13 . In this embodiment, the tension member  57  has an arcuate lower surface that engages the roller chain assembly  5 , as discussed below. 
         [0037]    II. The Load-Bearing Member 
         [0038]    The load-bearing member  11  is illustrated in  FIGS. 5-7 . In this embodiment, the load-bearing member  11  is a substantially rectangular plate that extends between and is attached to the sidewalls  17 . Specifically, the side edges of the load-bearing member  11  are received in the indentations  28  of the side walls  17 . Those side edges of the load-bearing member  11  are coupled to the side walls  17  as illustrated in  FIG. 7  and as explained below. Bars  59  with apertures are placed on the underside of the edges of the load-bearing member  11 . Fastening members  59   a  extend upward through those apertures, through holes in the side edges of the load-bearing member  11 , into and through holes in the side walls  17 . Fastening members  59   a  may be screws, bolts, pins, a combination thereof, or any other suitable fasteners. 
         [0039]    While in this embodiment, the load-bearing member  11  is a substantially rectangular plate, in other embodiments, the load-bearing member can have any shape and may be a structural member other than a plate. Further, in yet other embodiments, the load-bearing member can comprise multiple components joined and/or acting together to perform the load-bearing function described herein. 
         [0040]    III. The Motor Stacks 
         [0041]    Motor stacks  9  are illustrated in  FIGS. 1 and 2 . Motor stacks  9  include a motor, a brake, a gear head or series of gear heads, and a drive shaft  25 . The drive shaft  25  is rotated by the motor via the gear head or series of gear heads. The motors may be hydraulic motors, electric motors, or any other type of motor that is capable of providing the requisite torque. 
         [0042]    Motor stacks  9  are attached to side walls  17  of the frame  3 . In this embodiment, a motor stack  9  is attached to each side wall  17 , at opposite ends of the MCR  1 . Other embodiments of this invention may include a single motor stack, or more than two motor stacks. In yet other embodiments, the motor stacks can be attached to the same side wall of the frame, such as in the embodiment illustrated in  FIGS. 8 and 9  and described below. 
         [0043]    The drive shaft  25  extends inward through the aperture  23  in the side wall  17  to which the motor stack  9  is attached. The drive shafts  25  engage the sprocket assemblies  7  to rotate the sprockets of those assemblies with the necessary torque, as discussed below. 
         [0044]    IV. The Sprocket Assemblies 
         [0045]    The sprocket assemblies  7  are illustrated in  FIGS. 2-6 . In this embodiment, there are two sprocket assemblies  7 , with each sprocket assembly  7  being driven by the motor of a motor stack  9 . In other embodiments, only one of the sprocket assemblies may be driven by a motor and the other sprocket assembly may include an idler sprocket. Further, while in this embodiment, the sprocket assemblies  7  are located at the ends of the loop formed by the roller chain assembly  5  with the load-bearing member  11  located between the sprocket multiple load-bearing members located on opposite sides of the intermediate driven sprocket assembly. 
         [0046]    Further, in this embodiment, each sprocket assembly  7  includes a cylindrical member  50 , a drive shaft socket  51 , two teethed rings  47 , and a bearing ring  53 . The cylindrical member  50 , the drive shaft socket  51 , and the teethed rings  47  are an integral member. In other embodiments, the cylindrical member  50 , the drive shaft socket  51  and/or the teethed rings  47  can be separate members attached together. 
         [0047]    The drive shaft socket  51  receives and engages the drive shaft  25  of motor stack  9 , such that the drive shaft socket  51 , and thus the cylindrical member  50  and the two teethed rings  47  rotate with the drive shaft  25 . 
         [0048]    The teethed rings  47  include teeth  48  that engage the roller chain assembly  5 , to drive the roller chain assembly  5 , as discussed below. 
         [0049]    The bearing ring  53  is located around the drive shaft socket  51 . The bearing ring  53  permits rotational movement of the cylindrical member  50  and the teethed rings  47  relative to the side walls  17  of the frame  3 . While in this embodiment, that relative movement is permitted due to the bearing ring  53 , other bearing members can be used in other embodiments. 
         [0050]    V. The Roller Chain Assembly 
         [0051]    The roller chain assembly  5  is illustrated in  FIGS. 2-6 . In this embodiment, the roller chain assembly  5  includes a series of parallel and interconnected cylindrical roller sleeves  37 . More specifically, the roller chain assembly  5  includes a plurality of roller axles  45 , of cylindrical roller sleeves  37 , of inner links  39 , of engaging links  43 , and of outer links  41  (see  FIG. 4 ). There is a series of the inner links  39 , the engaging links  43  and the outer links  41  on each end of the roller axles  45  and the roller sleeves  37 . 
         [0052]    A cylindrical roller sleeve  37  is rotatably mounted on each axle  45 . Each of the cylindrical roller sleeves  37  has its own axis of rotation (see  FIG. 4 ), with all the axes of rotation being parallel. The cylindrical roller sleeves  37  may rotate in a clock-wise direction or a counter-clockwise direction, depending on the direction of movement of the roller chain assembly  5 . 
         [0053]    Each inner link  39  and each outer link  41  receives the ends of a pair of adjacent roller axles  45 . The same pair of ends of the roller axles  45  that is received in an inner link  39  is also received in an outer link  41 . Each engaging link  43  also receives the ends of a pair of adjacent roller axles  45 ; however, the pair of adjacent roller axles  45  whose inner link  39  is also received in an outer link  41 . Each engaging link  43  also receives the ends of a pair of adjacent roller axles  45 ; however, the pair of adjacent roller axles  45  whose ends are received in an engaging link  43  is not the same as any pair of roller axles  45  whose ends are received in an inner link  39  and an outer link  41 . Rather, the pair of roller axles  45  whose ends are received in an engaging link  43  includes a roller axle  45  whose end is received by one inner link  39  and one outer link  41  and a roller axle  45  whose end is received by an adjacent inner link  39  and outer link  41 . As a result, the roller sleeves  37  are interconnected through the axles  45 , the inner links  39 , the engaging links  43 , and the outer links  41 . 
         [0054]    As illustrated in the Figures, the series of engaging links  43  are located between the series of the inner links  39  and the series of the outer links  41 . The teeth  48  of the teethed rings  47  of the sprocket assemblies  7  engage the engaging links  43 , as discussed below. 
         [0055]    While in this embodiment, the roller axles  45  are connected by “chains” consisting of the inner links  39 , the engaging links  43  and the outer links  41 , in other embodiments, the roller axles can be connected by any link assembly that permits movement of the roller chain assembly  5  in the loop around the sprocket assemblies. Moreover, while this embodiment has two “chains,” a single “chain” may suffice. 
         [0056]    VI. The Guide Block Assemblies 
         [0057]    This embodiment includes two guide block assemblies  33  that are coupled to the front plate  19  of the frame  3 . See  FIGS. 1 and 2 . The guide block assemblies  33  include guide stops  35  that extend downwardly in a spaced relationship. Each guide block assembly  33  includes a pair of guide stops  35 . In this embodiment, guide stops  35  are cam followers, which include a mechanical bearing. In other embodiments, the guide stops can be other mechanical work pieces, including work pieces that include a bearing function. 
         [0058]    Guide stops  35  guide MCR  1  along a track (not shown) that may resemble the shape and configuration of a single train track. When used in that manner, the MCR  1  is positioned relative to the rail such that one of each pair of guide stops  35  is on each side of the rail. When the MCR  1  translates, the guide stops  35  keep the MCR  1  properly positioned vis-à-vis the rail. 
         [0059]    While in this embodiment there are two guide block assemblies  33  attached to the front wall  19 , in other embodiments, such as the embodiment illustrated in  FIGS. 8 and 9  (discussed below), there may be one or more guide block assemblies attached to the front wall and the back wall of the motorized chain rollers. Additionally, guide stops may protrude downward from other components of the frame or from guide block assemblies attached to other components of the frame, such as the sidewalls. 
         [0060]    VII. Assembly and Operation 
         [0061]    The MCR  1  is assembled as follows. The frame  3  is assembled as discussed above. The load-bearing member  11  is attached to the side walls  17  of the frame  3  by plates  59  and fastening members  59   a,  as also discussed above (see  FIG. 7 ). As further discussed above, the motor stacks  9  are attached to the exteriors of the side walls  17  such that the drive shafts  25  of the motor stacks  9  extend through the apertures  23  in side walls  17  into the interior of the frame  3 . The drive shaft sprockets  51  of the sprocket assemblies  7  are attached to the drive shafts  25 , such that those sprockets  51  and the cylindrical members  50 , teethed rings  47  and brake sockets  52  are driven by the drive shaft  25 . The roller chain assembly  5  forms a loop around the sprocket assemblies  7  and the load-bearing member  11 . The engaging links  43  of the roller chain assembly  5  are engaged with the teeth  48  of the teethed rings  47  of the sprocket assemblies  7 . 
         [0062]    The MCR  1  operates as follows. 
         [0063]    When the motors of motor stack  9  are activated, the drive shafts  25  rotate. The rotation of the drive shafts  25  causes rotation of the cylindrical members  50  and the teethed rings  47  of the sprocket assemblies  7  due to the drive shaft  25 /drive shaft sprocket  51  engagement. Because the teeth  48  of the teethed rings  47  engage the engaging links  43  of the roller chain assembly  5 , the rotation of the cylindrical member  50  and the teethed rings  47  causes the roller chain assembly  5  to move in its loop around the sprocket assemblies  7  and the load-bearing member  11 . 
         [0064]    The cylindrical roller sleeves  37  engage the underside of the load-bearing member  11 . That engagement causes propulsion of the MCR  1  or of objects being conveyed by the MCR  1 , depending on the mode in which the MCR  1  is being used (the two modes are discussed below), as the roller chain assembly  5  is driven in its loop. 
         [0065]    The MCR  1  has two modes of operation. 
         [0066]    The first mode of operation is in the orientation illustrated in the Figures. The chain roller assembly  5  is in contact with the ground, pavement or building floor and the object(s) to be transported are on top of the top load-bearing plate  13 . Activation of the motors of motor stacks  9  causes movement of the roller chain assembly  5  in its loop around the sprocket assemblies  7  and the load-bearing member  11 , as discussed above. Because the cylindrical roller sleeves  37  in the lower portion of the loop formed by the roller chain assembly  5  are “pinched” between (or in engagement with) the load-bearing member  11  and the ground, pavement or floor of a building, movement of the roller chain assembly  5  in its loop causes translation of the MCR  1  along the ground, pavement or floor of a building. More specifically, the cylindrical roller sleeves  37  in the lower portion of the loop are in engagement with both the load-bearing member  11  and the ground, pavement or building floor. Movement of those roller sleeves  37  in the loop causes those roller sleeves  37 , and thus the entire MCR  1 , to move laterally, because the individual roller sleeves  37  “roll” along the ground, pavement or building floor. 
         [0067]    The motors of motor stacks  9  are reversible, such that MCR  1  can go forward or backward. 
         [0068]    In the second mode of operation, the MCR  1  is inverted from the orientation illustrated in the Figures such that the top load-bearing plate  13  of the frame  3  rests on the ground, pavement or floor surface and the underside of the roller chain assembly  5  is facing upward. In this orientation, the MCR  1  functions as a load conveyor, because the MCR  1  does not move. 
         [0069]    In this second mode of operation, the object(s) to be conveyed are placed on top of the exposed portion of the roller chain assembly  5 . When the motors of motor stacks  9  are activated, the cylindrical members  50  and the teethed rings  47  are still rotated by the drive shafts  25  of the motor stacks  9 . That again causes the roller chain assembly  5  to move in its loop around the sprocket assemblies  7  and the load-bearing member  11 . Because the roller chain assembly  5  is in firm engagement with the load-bearing member  11  and the underside of the object(s) being conveyed, movement of the roller chain assembly  5  in the loop causes the objects being conveyed to move laterally with the roller chain assembly  5 . 
         [0070]    Multiple MCRs  1  may be aligned such that an object or objects may be transported on top of the cylindrical roller sleeves  37  of multiple roller chain assemblies  5 . 
         [0071]    The interplay of the load-bearing member  11  and the roller sleeves  37  in contact with the load-bearing member  11  causes the force from the load being transported to be evenly distributed on the load-bearing member  11 , the frame  3  and the roller chain assembly  5 . That is advantageous because heavier loads may be transported with the same amount of lateral force as compared to conventional moving mechanisms that do not equally distribute the weight force of the loads. 
         [0072]    Regardless of the orientation of MCR  1 , the tension member  57  applies a tension force to the roller chain assembly  5  to prevent slack in the roller chain assembly  5  and ensure that the roller chain assembly  5  efficiently transmits force from the sprocket assemblies  7  into lateral movement. 
         [0073]    A second embodiment of the invention is illustrated in FIGS.  8  and  9 —MCR  1   a.  The components of the MCR la are given the same reference numbers as the corresponding components of the MCR  1 , except that a suffix “a” is added. 
         [0074]    In this embodiment, the motor stacks  9   a  include direct motors. That is, the drive shaft  25   a  is directly driven by the motor, without any intervening gears. This embodiment also includes brakes that are external to the motor stacks  9   a,  brakes  61 . Also in this embodiment, the sprocket assemblies  7   a  include brake socket  52 . The brakes  61  engage the brake sockets  52 . Each brake  61  is operated by a brake solenoid  63 . The brakes  61  may be drum brakes, disc brakes, or any other type of brakes that retards rotation of the cylindrical members  50   a  and the teethed rings  47   a.    
         [0075]    Also, in this embodiment, motor stacks  9   a  are attached to the same side wall  17   a.  Moreover, guide block assemblies  33  are replaced by guide flanges  33   a,  with a guide flange  33   a  being attached to each of the front wall  19   a  and the back wall  21   a.  The guide stops  35   a  extend downward from the guide flanges  33   a  in a spaced relationship, such that a track can be received between each pair of the guide stops  35   a.    
         [0076]    Due to the arrangement of the frames, motors, sprocket assemblies, load-bearing members and chain roller assemblies of the embodiments illustrated in the Figures, the height of the illustrated motorized chain rollers can be less that 20 inches and preferably as low as approximately 13 inches, but may be even lower. 
         [0077]    What has been described and illustrated herein are preferred embodiments of the invention along with some variations. The terms, descriptions and figures used herein are set forth by way of illustration only and are not meant as limitations. Those skilled in the art will recognize that many variations are possible within the spirit and scope of the invention, which is intended to be defined by the following claims—and their equivalents—in which all terms are meant in their broadest reasonable sense unless otherwise indicated.