Abstract:
A product retrieval mechanism for vending machines that permits collection of varying size products at a first level yet presents such products for collection at a raised height to make retrieval more convenient. The retrieval mechanism utilizes a movable floor within the hopper that movable between a lowered position and a higher position for presenting the product at a higher retrieval point relative to the floor upon opening of the hopper.

Description:
COPYRIGHT NOTICE 
       [0001]    A portion of the disclosure of this patent document contains material that is subject to copyright or mask work protection. The copyright or mask work owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright or mask work rights whatsoever. 
       FIELD OF THE DISCLOSURE 
       [0002]    This disclosure relates to vending machines and more specifically to a product retrieval system that receives a dispensed product at one level and presents that product at a different and higher level for collection. 
       INTRODUCTION 
     Glossary: As Used Throughout this Document 
       [0003]    The term “hopper” and the phrase “tilt hopper” shall mean a form of retrieval bin characterized by having a bottom or floor that is movable between lowered and raised positions, for example one lowered position that will assist in the initial receipt of any sized product that is dispensed from a product tray or other product retaining mechanism there above in a vending machine into the retrieval bin or hopper and onto an actual floor within the hopper or bin structure, yet when the retrieval door is opened the floor will have been moved to its raised position to thereby present such a dispensed item for collection by a purchaser at a higher point and thereby be in compliance with and will meet the latest Americans with Disability Act requirements. 
         [0004]    The term “retrieval mechanism” refers to a system used in a vending machine that receives dispensed product at a first lower level and when accessed by the consumer, presents that dispensed product at a second higher level for collection by that customer. 
         [0005]    The term “actual floor” or “actual bottom” means the lowered, true floor within the hopper of the retrieval mechanism when the retrieval door is closed and the security shield is open, with the depth of the actual floor being defined by the vertical dimension at the center of the interior of the hopper. 
     
    
     
       DESCRIPTION OF PRESENTLY PREFERRED EXAMPLES OF THE INVENTION 
       Brief Description of Figures 
         [0006]    The invention is better understood by reading the following detailed description with reference to the accompanying drawings in which: 
           [0007]      FIG. 1  is a front elevational view of the vending machine; 
           [0008]      FIG. 2  is a cross-sectional view taken along line  2 - 2  in  FIG. 1 ; 
           [0009]      FIG. 3  is an perspective view of the hopper from the front side; 
           [0010]      FIG. 4  is a perspective view of the hopper from the rear thereof; 
           [0011]      FIG. 5  is a perspective view of the bottom of the hopper; 
           [0012]      FIG. 6  is a front elevational view of the side of the hopper showing the floor in a lowered condition, with parts having been omit for clarity; 
           [0013]      FIG. 7  is a cross sectional view taken along line  7 - 7  in  FIG. 6 ; 
           [0014]      FIG. 8  is a front elevational view of the side of the hopper showing the floor in a raised condition, with parts having been omit for clarity; 
           [0015]      FIG. 9  is a cross sectional view taken along line  9 - 9  in  FIG. 8 ; 
           [0016]      FIG. 10A  is a cross sectional view taken along line  10 - 10  in  FIG. 6 ; 
           [0017]      FIG. 10B  shows an enlarged elevational drawing of the door stop cam; 
           [0018]      FIG. 11  shows an end view of an open retrieval bin mechanism with the security shield in a fully open, non-shielding position; 
           [0019]      FIG. 12  shows an end view of the hopper with the security shield in a partially closed position; 
           [0020]      FIG. 13  shows a retrieval bin mechanism in which the security shield in its closed, shielding position; 
           [0021]      FIG. 14  shows a front elevational view of the hopper delivery door with parts having been deleted for clarity; 
           [0022]      FIG. 15  shows a side view of the delivery door taken along line  14 - 14  in  FIG. 13 ; and 
           [0023]      FIG. 16  shows a control circuit for the present invention. 
       
    
    
     DETAILED DESCRIPTION 
     A. Overview 
       [0024]    To gain a better understanding of the invention, a preferred embodiment will now be described in detail. Frequent reference will be made to the drawings, and reference numerals or letters will be used throughout to indicate certain parts or locations in the drawings. The same reference numerals or letters will be used to indicate the same parts and locations throughout the drawings, unless otherwise indicated. 
       B. Environment 
       [0025]    The preferred embodiment now described will be with respect to a glass front vending machine. The scale of the embodiment, therefore, is to be understood with respect to this type of device or equipment. However, the present retrieval system could work for other vending machines, for example closed front vending equipment, so long as the path of travel of a vended product was directed into the hopper opening when the retrieval door is in its closed position. It is to be understood as well, however, that the invention is applicable to other articles and its scale can vary accordingly. 
         [0026]    It can be pointed out as well that the hopper or hopper assembly disclosed and discussed herein can be smaller and more compact and positioned at a lower level in the vending machine thereby permitting a larger product holding section as the bottom thereof can extend downwardly an additional distance lower that would otherwise be the case with a higher and less compact hopper or retrieval assemblies. Consequently, vend capacity and shelf height can be maximized. 
       C. Structure 
       [0027]      FIGS. 1 and 2  show such a glass front vending machine  10  as being comprised of an outer casing  12  comprised of a front door  14  that is hinged or otherwise attached to a rear portion  16  comprised, for example, with a top wall  20 , opposing side walls  22  and  24 , and rear and bottom walls,  26  and  28 , respectively, as well as a plurality of height adjustable feet  26 . The front door  14  and the rear portion  16  collectively define the outer casing structure  12  for the vending machine  10 . 
         [0028]    The front door  14  includes a glass front  30  that is retained in a front panel  32 , as well as opposite sides  34  and  36 , a top  38  and a bottom  40 . Door  14  also includes a change return  42 , a suitable keypad control panel  44 , a display  360  and a retrieval mechanism  50 . As shown in  FIG. 8 , an additional vertical interior wall  37  can be provided at a point spaced inwardly from side wall  36  with the space between walls  36  and  37  providing room to mount other parts of the vending machine such as, for example, electronics, a coin changer assembly, a bill validator or other devices as may be desired on vending equipment. The amount of spacing between walls  36  and  37  varies with the size and capacity of the vending machine  10  and therefore also affects the relative size of retrieval mechanism  50 . 
         [0029]    Inside the vending machine  10  is a product holding section  60 , as shown in  FIG. 2 , that can include any form or grouping of known product dispensing assemblies, product holding and dispensing trays, or other product holding and dispensing devices as one might envision for such a vending machine  10 . The precise content, size, structure and configuration of the product holding section  60  can include or encompass a wide variety thereof limited only by the particular products one might choose to vend from each tray or device within the vending machine as a whole. Suitable vend motors  380  can be used as needed on each dispensing tray  382  or product dispensing arrangement however designed to dispense product therefrom. Also included inside the vending machine is a vend space  62  that exists both vertically and horizontally, with the horizontal width being defined by and between the interior portions of the vertically extending side walls  34  and  37 , and with a front-to-back depth defined between the front of the product holding section  60  and the inside of glass  30 . A dispensed product will fall through this vend space  62  and into the retrieval mechanism  50 . 
         [0030]    The vending machine  10  can also include a vend sensing system, for example a Sensit® system which can be better understood by reference to U.S. Pat. No. 6,384,402, incorporated herein by reference thereto. This vend sensing system is shown generally at  70  in  FIG. 4  and includes an emitter/detector unit  70 A on one side of the vend space  62  and a second emitter/detector  70 B unit on the opposite side, along with suitable control equipment, and comprises a product vend detection system for the vending equipment. This sensing system can, for example, be positioned as shown in  FIGS. 4 and 14  adjacent the bottom of the vend space  62  but just above the hopper mechanism  100  and for example, can be directed above and across the depth or the front to back dimension of the top edges  105  and  107  of walls  104  and  106 , respectively. A sensing plane of radiation will be generated to extend and operate across the depth and width of the vend space  62  to sense the vending of a product as it falls through the Sensit® radiation plane into the retrieval mechanism. 
         [0031]    When glass bottles or fragile products are being vended it may be desirable to also provide an additional product sensor  72  with, for example an emitter or emitter/detector combination  72 A on one side of the hopper space and a detector or emitter/detector combination  72 B on an opposite side of the hopper, to detect that a product is actually located within the hopper itself to prevent another product from being vended on top of such a glass or fragile product already within the hopper. 
         [0032]    Turning to  FIGS. 3 and 4  the retrieval mechanism  50  can include a hopper assembly, shown generally at  100 , that can include an inner hopper structure comprised of a rear or back wall  102 , side walls  104  and  106 , and a front wall or panel  108 . Side wall  104  includes a front portion comprised an upper tab or flange  110  and a lower tab or flange  112  bent at about a 90° angle to side wall  104 , with each having a plurality of mounting holes  114  provided therein thereby permitting the hopper assembly  100 , for example, to be mounted to door  14 . Side wall  106  also includes a series of tabs or flanges  116 ,  118  and  120 , also bent at about 90° to side wall  106 , which have mounting holes  122  provided therein. 
         [0033]    Front panel  108  includes two spaced apart openings  130  and  132  thus providing an opening through which pivotally mounted doorstops  134  and  136  can operate, respectively, as will be discussed further below. 
         [0034]    The hopper assembly  100  also includes a pivotally mounted security shield  140  having a curved main section  142  that is curved, with a front edge  141 , a rear edge  145 , and end panels  144  and  146  each of which is respectively pivotally mounted to side walls  104 / 106  by pivot assemblies  148  and  150 , respectively. The curved main section  142 , for example if formed from stamped sheet metal, can be provided with tabs or flanges as are shown at  152 ,  154  and  156  that are secured to the end walls, for example as is shown in  FIG. 3  for end wall  146 , by rivets  158 . The curved main section  142  can be connected to end wall  144  in a similar manner. Alternatively, the curved main section  142  might be formed with end walls  144  and  146  as a one piece molded structure from a moldable material, for example a plastic, thermoplastic or a polycarbonate type of material, in which case the connecting flanges and rivets would not be needed. As shown in  FIG. 4  the shield  140  is in its open position and its rear edge  145  will rest on spaced apart stops or bumpers  143 . 
         [0035]    The hopper assembly can be made from sheet metal, for example, and the gauge thereof can vary from 12 to 22. Alternatively, the hopper assembly could be molded form a plastic or reinforced plastic, as well as a polycarbonate, or other similar man made types of materials. 
         [0036]    The hopper assembly  100  also includes a bottom interior wall, generally shown at  170 , which can be comprised of substantially flat first and second floor sections,  172  and  174  respectively. Each of the floor sections  172 / 174  have an inner edge  176  and  178 , and outer edges  180  and  182 . The two inner edges  176 / 178  are movably connected to one another, for example by being pivotally connected through a central hinge  184 , while outer edge  180  of section  172  is movably connected to side wall  104 , for example, by a hinge  186 . The other outer edge  182  is also movably connected to side wall  106 , again for example by a hinge  188 . A pair of stops  190  and  192  are provided on a back surface of rear wall  102  and are located near a bottom edge to provide a positive stop for an fully opened position for security shield  140  as is shown in  FIG. 10 . 
         [0037]    What is important is that floor sections  172 / 174  are moved relative to each other, and relative to hopper side walls  104 / 106 . One example, as noted, is to use hinges to permit pivotal motion. However, other forms of hinge devices or structures could also be employed, for example, use of man-made materials such as polycarbonate, polyethylene, plastics, or other such materials a hinges or floor section connectors that would permit floor sections  172 / 174  to be moved between their lowered and raised positions. 
         [0038]    On each side of the hopper assembly  100  is a pivot link mounting bracket  200  and  202  that can be riveted or otherwise secured to a lower portion of side walls  104 / 106 . As an alternative, tabs or flanges  110  and  120  could also be formed as a part of that bracket  200 / 202 , as opposed to the side walls  104 / 106 , and are still bent at a ninety degree angle. 
         [0039]    With reference to  FIGS. 5, 6 and 8 , the bottom area of the hopper assembly  100  can be seen and shows a first and long horizontally extending drive shaft  210 , having for example a hexagonal cross sectional shape, that is mounted at one end  213  to an inside surface of bracket  200  by a retaining bracket  212 , that can be riveted to bracket  200 , with the end of shaft  210  itself being supported therein by a snap in NYLINER® bearing  214 . The opposite end  215  of drive shaft  210  extends into a motor  270 , to which it is drivingly connected. A second short drive shaft  216  has one end that is also operatively connected to motor  270  and a second end that is rotationally supported by a bearing  217  in bracket  202  and is operatively connected and fixed to one end of a drive link  218 . 
         [0040]    Drive shaft  210  supports a pair of large cam discs,  220  and  222 , and a pair of smaller cam discs  224  and  226 . The large cam discs  220  and  222  work with cam followers  228  and  230  that are attached to the bottom of floor sections  172  and  174 , respectively. As  FIG. 6  shows, when cam discs  220  and  222  are rotated to a first position by motor  270 , the floor sections  172 / 174  will be in a lowered condition. When cam discs  220 / 222  have been rotated 180 degrees, as in  FIG. 8  from the previous position of  FIG. 6 , cam discs  220 / 222  will have moved followers  228 / 230  upwardly thereby moving floor sections  172 / 174  to a fully raised condition making the floor flat and having raised any selected and vended product resting on floor  170 . To meet ADA requirements the floor  170  will preferably move about 2.25 inches from its lowest point, shown in  FIG. 6 , to its highest point, shown in  FIG. 8 . A wider range for this floor movement would be possible to fit other vending machine mechanisms or vended product sizes. 
         [0041]    Shaft  210  also drives smaller cam discs  224  and  226  that will move against door stops  134  and  136 , respectively. Those door stops  134 / 136  are pivotally supported in brackets  234  and  236  by pins or bolts  238  and  240 . 
         [0042]    The larger cam discs  220  and  222  have an outer diameter of 2.33 inches and the center of the drive shaft  210  is 0.56 inches from the short side and 1.77 inches from the ling side. The smaller cam discs  224  and  226  have a specially designed shape, as shown in  FIG. 9  and in greater detail in  FIG. 10 , with an overall outer diameter of about 1.5 inches, and with the center of drive shaft  210  being about 0.312 inches from the short side and about 0.750 inches from the longer side. Both sets of cams can be formed, for example, from a Lexan® 923a polycarbonate material or a like material. 
         [0043]      FIGS. 1, 9, 10A, 14 and 15  show the retrieving door  300  that can move between a down or open position and in a up or closed position. In  FIG. 10A , stop  134  is shown as having a “T” shape with a long portion  302  with a top end  304  that will engage the bottom  306  of door  300 , a bottom end  308  that is pivotally connected by a pin  238  to a bracket  234  that is secured to front wall  108  as shown in  FIGS. 5, 6 and 10 , and a short arm  310  having an outer end  312 . Each stop  134 / 236  is mounted to be biased inwardly by a spring  314 . Cams  224 / 226  as shown in  FIG. 10B  will be rotated clockwise by the drive shaft  210 . In order to again place stops  134 / 136  back in their out or locking position, drive shaft  215  will once again be rotated and surface  324  will eventually be brought into contact with the contact end  312  of the short arm  310  and continued rotation will thereby push stop  134 / 136  outwardly against the force of spring  314  toward their outward or door stopping, locked positions. 
         [0044]    The position of door  300  will be monitored by a switch  330 , shown in  FIGS. 7, 9, 14 and 16 , that will be actuated by door  300  when moved into its closed or up position. When switch  330  is actuated or closed drive shaft  210  can rotate cams  222 / 224  to push stops  134 / 136  into their stop position as just described. 
         [0045]    Door  300  will slide within rails  340  and  342  and each side  344  and  346  will be attached to a spring  348  and  350  that will be pulled from a reel mounted within an enclosure  352  and  354  located adjacent the upper corners of door  300 . As door  300  is moved downwardly into its open condition springs  348 / 350  will be pulled from enclosures  352 / 354  and will be biased to help move door  300  upwards into its closed condition. 
         [0046]    Cams  224 / 226  have a defined outer shape, as shown in  FIG. 10B , comprising a major portion of the outer periphery or circumference, as indicated at  320 , and a shallowed profile  322 . If a vertical axis “A” is drawn on the cam  224  in  FIG. 10B , the major circumferential portion  320  extends, for example, from about 35° counter clockwise to about 180°, with the shallowed portion beginning at about the same 35° point but extending clockwise to about the same 180° point. The entire outer periphery will come into contact with end  312  of the top members  134 / 136  and depending upon the rotation of shaft  210  the stops  134 / 136  will be held in an projected or locked condition for holding door  300  and preventing door  300  from being opened, as shown in  FIG. 10A , or in a biased inward condition as shown in  FIG. 9 . While end  312  is in contact with the major portion  320  the stop  134 / 136  remains closed, but as end begins to be contacted by the shallow side adjacent the 35° point the stop  134 / 136  will begin its movement out of contact with stops  134 / 136  and the top end  304  will move inwardly and out of contact with the bottom  306  of door  300 . As drive shaft  210  moves to raise floor  170  and to present a dispensed product for collection and the door  300  will then be unlocked and openable by moving handle  301  down. 
         [0047]    As mentioned above, the security shield  140  is pivotally mounted and is movable between open and closed positions. That movement is controlled by a series of linkages and motor  270  and drive shafts  210 / 216 . An end  215  of the short drive shaft  216  is connected to one end of a drive link  218 , as shown in  FIG. 3 . Link  218 A on the opposite side, as in  FIGS. 11-13 , will be driven by drive shaft  210 . The other and opposing end of drive link  218  is pivotally connected at  251  to one end of a link  250  the opposite end of link  250  being connected at a pivot point  252  to one end of a pair of links  254  and  256 . The opposite end of link  254  is pivotally connected to mounting bracket  200  at a pivot connection  258  and the opposite end of link  256  is pivotally connected to an end wall  144  of the security shield  140  at a pivot connection  260 .  FIGS. 11-13  show the same security shield drive links, which are also connected and driven and operate as just described, but with an “A” along with the appropriate reference numeral (e.g.,  250 A). 
         [0048]      FIGS. 11-13  show the movement sequence for the rotation of the pivotally mounted security shield  140  from its open to its closed positions. As motor  270  rotates the short drive shaft  216  and the long drive shaft  210 , the drive link  218  (and  218 A on the opposite side) will start to rotate thereby driving links  250 ,  254  and  256  (and  250 A,  254 A and  256 A) that will progressively rotate the security shield  140  from its open position ( FIG. 11 ), where it rests on a pair of resilient stops  143  and in which dispensed product can drop or fall into the hopper assembly  100 , through an intermediate position ( FIG. 12 ) to its fully closed position ( FIG. 13 ). When closed, security shield  140  will cover and close the top of the hopper assembly  100  thereby preventing access into vend space  62  and likewise will prevent attempts to dislodge additional products retained in the product holding section  60 .  FIG. 4  shows two micro switches one, switch  280 , to sense the down position, and a second switch  282  to sense and then signal the fully closed position of shield  140 . Switch  280  will be tripped by an extension  284  in the form of a protruding end on end wall  146 , and switch  282  will be tripped or closed by an actuation plate  286  on a leading edge  288  of the end wall  146 . 
         [0049]    When the vendor begins the vend process (assuming credit, and no errors), the motor  270  will turn the drive shafts  215  and  216 ˜180 degrees, stopping when an actuator  284  on the security cover  140  closes a micro switch  280 , signaling that the cover  140  is fully open. The half revolution also operates two cams  220  and  222  that lower the floor sections  172  and  174  and two other cams  224  and  226  that control the movement of two door locking or stop arms  134  and  136  out under the slidably mounted vend door  300  to lock it closed. If, at any time during this movement, the sliding vend door  300  opens switch  330  (indicating it is not fully up or not closed), the motor  270  will stop and activate a display stating “please close vend door” or something to that effect on the display  360  on the front of the vending machine  10 . This prevents jamming the mechanisms, as well as attempts at ‘fishing’ for merchandise through the hopper assembly  100 . Next, the vend motor  380  turns to dispense a selected product from the product holding section  62 , relying on the Sensit® sensor system  70  to detect a successful vend and to then stop vend motor  380 . If used product sensors  72 A/ 72 B can also confirm that a product is within the hopper. Then the motor  270  makes another half turn of the drive shafts  210 / 216 , stopping when the security cover  140  is fully closed which is sensed by the activation of micro switch  282 . During this half turn, the floor  170  is also raised to the minimum height required by the ADA. Also, cams  224 / 226  will have rotated to a position that will permit the retracting or inward movement of the locking arms  134 / 136  thereby unlocking door  300  to allow the vend door  300  to be lowered by the customer in order to retrieve the dispensed product from within the hopper assembly  100 . When door  300  is released by the consumer it will again raise to its closed position. The vending machine will then stay at this position until another vend is requested. The hopper stays at this ‘vend’ position until another selection is made, so the door can be opened/closed as needed to access the product. 
         [0050]    As noted previously, security shield  140  can be comprised of a one piece molded structure or preferably formed as a multi-segmented structure from, for example, 24 gauge steel. Walls  102 - 108  are preferably formed or stamped from 16 gauge galvanized steel, and the separate linkage members  250 ,  254  and  256  can also be formed or stamped from 16 gauge galvanized steel as well as the mounting brackets  200  and  202 . It should be understood, however, that other gauges of sheet metal could be sued as well as other materials, informing the various parts of the hopper assembly  100 . 
         [0051]      FIG. 16  shows an exemplary control circuit for this vending machine as including a control board that is powered by a 24 VDC power source  372  and is further connected to vend motors  380 , a display  360 , a money input device  374  that includes a suitable sensor to know the amount being paid, the keypad  44 , the Sensit sensor system  70 , the in-hopper sensors  72 A/ 72 B if used, the door switch  330 , as well as the security shield switches  280  and  282 , and hopper motor  270 . Suitable wire harnesses  382  can also be provided as need to provide power or signals to the motors, sensors, and other electrical components. 
       Operation 
       [0052]    In operation, with the retrieval door  50  being in its closed condition, a consumer will insert cash or credit by inserting money into the money input device  374  and the value will be displayed on display  360 . A product can then be selected via keypad  44  and the display will also show and confirm the selected item. The control board  370  will then check that vend door  300  is closed, by seeing if switch  330  is made or closed, and hopper motor  370  will then be activated for a partial rotation sufficient to fully open security shield  170  as shown in  FIG. 11 . If during this period door  300  is opened, with switch  330  opening, hopper motor  270  will stop and a warning will be scrolled across the display  360  that the retrieval door  300  is open. With door  300  closed, and with shield  140  fully open, as sensed by switch  280 , the control board can check sensors  70 , and/or  72 A/ 72 B to assure a clear vend field exists. When that condition is present, the proper vend motor will be turned on to dispense the selected product. That selected product will follow a path of travel, for example through a vend space as shown at  62 , and eventually fall or drop into the interior of the hopper assembly  100  and onto the lowered floor or bottom  170 . In the glass front vending machine  10  as shown herein, the dispensed product will also have fallen freely through vend space  62  and will have been detected by the Sensit® system  70  which will detect a positive vend. Once the product has been properly vended the customer&#39;s deposited money will be accepted. As the dispensed product passes through the Sensit beams the control board  370  will also stop the specific vend motor  380  and powers the hopper motor  270  to close the security shield  140 , as in  FIG. 13 , and hopper motor  270  will stop once switch  282  is closed indicating the closed condition for shield  140 . As hopper motor  270  is rotating the security shield  140  into its closed condition cams  220 / 222  will raise floor  170  and cams  224 / 226  will retract door stops  134 / 136  thereby unlocking door  300 . The customer can then grip handle  301  to open door  300 . The dispensed product, now be resting on floor  170 , will have been raised to a height that is significantly higher and readily accessible permitting the consumer to remove the vended and dispensed product and then close door  300 . When switch  330  is once again activated by door  300  moving to its closed or up position, the control system  370  will be reset and thereby ready for the next vend cycle. 
         [0053]    When introducing elements of various aspects of the present invention or embodiments thereof, the articles “a,” “an,” “the” and “said” are intended to mean that there are one or more of the elements, unless stated otherwise. The terms “comprising,” “including” and “having,” and their derivatives, are intended to be open-ended terms that specify the presence of the stated features, elements, components, groups, and/or steps, but do not exclude the presence of other unstated features, elements, components, groups, and/or steps and mean that there may be additional features, elements, components, groups, and/or steps other than those listed. Moreover, the use of “top” and “bottom,” “front” and “rear,” “above,” and “below” and variations thereof and other terms of orientation are made for convenience, but does not require any particular orientation of the components. The terms of degree such as “substantially,” “about” and “approximate,” and any derivatives, as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. For example, these terms can be construed as including a deviation of at least +/−5% of the modified term if this deviation would not negate the meaning of the word it modifies. 
         [0054]    While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.