Abstract:
The disclosed pads are engaged with dumpster supports to spread the weight of the dumpster over a large surface area and provide a relatively soft ground contact interface to prevent damage to paved surfaces on which the dumpster may be placed. The pads define a cavity complementary to the dumpster support and may be affixed to the support by straps or fasteners. The pads can be constructed of flexible material and distorted to open the cavity to receive the support, then relaxed to grip the support. The pads have a ground contact surface greater than a contact surface of the dumpster support and may include grooves in the ground contact surface.

Description:
TECHNICAL FIELD 
       [0001]    The present invention generally relates to dumpsters employed for disposal of waste. More particularly, the present invention is directed to apparatus and methods for preventing damage to paved surfaces on which dumpsters are placed. 
       BACKGROUND OF THE INVENTION 
       [0002]    A so called “roll off” dumpster is usually an open top rectangular container equipped with wheels to facilitate placement and removal of the dumpster. Construction debris may originate from a building site where something is being built, renovated, or demolished. Roll-off dumpsters are used for moving material away from a work site. The material in the roll off may be taken to a landfill, recycled, or disposed/recovered in some other way. 
         [0003]    The debris container of a roll off dumpster is typically an open top rectangular reinforced steel box designed to be transported by special roll-off trucks. Some roll-off dumpsters have a swinging door on one longitudinal end to facilitate loading and disposal of waste. Roll-off containers typically have a rectangular footprint typically determined by the size of typical trucks. Roll-off container sizes are determined by the amount of volume of debris they contain. Typical container sizes in the United States are 10, 15, 20, 30, and 40 cubic yards. A typical 40 cubic yard container may, for example, be 6′ 5″ high by 21′ 6″ long and 8′ 6″ wide and may have a load limitation imposed by a rental entity of six tons. Even larger 100 yard containers that measure 8′ wide, 48′ long and 136″ high are also available. Weight limits are necessary to ensure compliance with road-use and safety laws and regulations as well as the integrity of the container and truck. Large roll off dumpsters typically have four metal roller-shaped wheels disposed at the corners of the rectangular container. Smaller roll off dumpsters have two wheels on one end and a pair of runners at the opposite end of the container. Roll-off dumpsters are placed by roll-off trucks equipped with a hydraulically operated bed and rails arranged to align with the wheels. The bed is raised and a cable is used to slowly lower the container until the rear-most pair of wheels contacts the ground. After the waste container is loaded with debris, the roll-off truck pulls the filled container onto the roll-off truck by using a cable and winch system. Some roll-off trucks may employ a hook-lift system. 
         [0004]    Front load dumpsters are also relevant to the disclosure. Front load dumpsters are commonly used for waste handling at businesses, condominiums and apartment complexes. Front load dumpsters typically include sliding doors for waste disposal and pivoting covers to enclose the top of the container. Front load dumpsters include channels open toward the front of the dumpster that are engaged by two large elongated forks extending generally forward of the cab of the truck. Front load dumpsters are emptied by inserting the forks into the channels and hydraulically raising the dumpster to tip the contents into the waste bin of the truck, then lowered again. Front load dumpsters rest on box shaped steel tubing extending across the bottom of the debris container. 
         [0005]    One problem often encountered with roll-off dumpsters as well as front load dumpsters is liability for damaging the surface on which the container is placed. Most dumpsters are placed by necessity on paved surfaces such as asphalt or concrete. Damage to the surface on which the container is placed, such as a concrete or asphalt paved surface, may occur during placement, removal or even when the container merely rests on the surface for an extended period of time. It will be understood that such containers are often very heavy when empty and extremely heavy when loaded. The damage to asphalt surfaces is most extreme in warm weather occasions which soften the asphalt. 
         [0006]    The use of cylindrical wheels to support such containers on a planar support surface result in a line contact between the cylindrical wheel and the support surface. Cylindrical wheels and narrow steel rails concentrate the force of the dumpsters on the support surface in a small surface area, which can damage the surface. Any backward or forward movement of the truck during placement increases the surface area that is damaged. It is also possible for wheel-supported dumpsters to roll on an inclined surface, which can be very dangerous to persons and traffic in the vicinity. The box tubes on the bottom of front load dumpsters tend to rust due to ground contact, leaving rust stains on the support surface. Rusted out support tubes must eventually be replaced. 
         [0007]    It is common for dumpster companies and property owners to use wood sheets or blocks to support a dumpster and prevent damage to the support surface. Trucks used to deliver, retrieve and empty dumpsters are typically operated by a single driver/operator, so one problem with this approach is that the operator of the truck used to place the container cannot see the precise location of the plywood at the time of container placement. This can result in the dumpster missing the wood, and may necessitate the operator getting in and out of the vehicle cab several times when dropping off a dumpster. Further, the blocks or wood sheets must be delivered with the dumpster, and the dumpster trucks do not typically have room to safely store and transport such materials. It is not permitted to have such heavy objects loose in the cab of the truck. 
         [0008]    There is a need in the art for apparatus and methods to reduce the potential damage to paved support surfaces that can result from the use of dumpsters. 
       SUMMARY OF THE INVENTION 
       [0009]    The disclosure relates to pads configured to engage the support wheels, rails or box tube of various dumpster configurations. The pads are configured to securely engage the support, whether it is a wheel, a rail, or a box tube. The pads raise the dumpster off the support surface, permitting normal flow of surface water beneath and around the dumpster, while reducing moisture exposure and rust on the dumpster itself. The pads may be constructed of relatively soft, tough material such as recycled rubber or plastic that will not permanently mark the support surface. The pads may be constructed using any known methods such as molding, extruding, lamination from sheet materials, etc. The pads are configured to expand the surface area upon which the dumpster is supported, reducing local surface pressure and the likelihood of surface damage. The pads may be configured to permanently mount to the dumpster using hardware, or may be installed only when the dumpster is deployed on a support surface. 
         [0010]    The configuration of the disclosed dumpster pads will vary depending upon the type of dumpster and the support structure to which the pads will be secured. In embodiments for use with a wheel-supported dumpster, the pad will be configured to fit over the wheel and provide an enlarged rectangular support surface in place of the line of support provided by the wheel. Dumpster wheels vary in size and the disclosed pads are sized to fit the most common wheel diameters and widths. The pad will include a cylindrical inside surface configured to receive wheel and mate with the outside surface of the wheel. The pad may extend around more than one half the circumference of the wheel, resulting in a configuration that may grip the wheel. This pad configuration also serves as a “chock” for the relevant wheel, preventing rolling of the wheel along the support surface. 
         [0011]    In some embodiments the pad has an elongated channel configured to receive a rib projecting from the associated dumpster. Pads may also be configured to fill the end of box tubes and extend beneath the box tubes to raise the dumpster off the ground. In some embodiments, the pad may include a plurality of grooves in the ground contact surface of the pad. The grooves may be arranged transverse to the length of the pad to promote water flow past and around the pad. Grooves may extend in more than one direction to promote frictional engagement with the support surface. 
         [0012]    The pads are generally configured to expand the surface area upon which the dumpster rests. The pads have a length and width suitable for this purpose and may increase in length and width as the pad progresses way from the dumpster toward the ground. 
         [0013]    Pads configured for use with box tube support members may include a channel on an upper surface, where the channel is configured to receive the lower portion of the box tube. The channel may be defined between first and second walls disposed in space relationship and projecting upwardly from a base of the pad. Such embodiments may further include a generally rectangular plug dimensioned for snug engagement with the open end of the box tube. The plug projects into the channel from one end, meaning that there are pads configured to close each end of the box channel. The pad base and channel extend longitudinally beneath the box tube, providing an expanded support surface area and raising the box tube off the ground. The pad may be secured to the box tube using hardware passing through openings in the pad. 
         [0014]    Embodiments of a pad in accordance with aspects of the present disclosure may be manufactured from suitably durable materials. Some elasticity is helpful to installation and removal of the disclosed pads. For example, such pads may be manufactured of rubber, recycled rubber, rubber reinforced by fibers or the like, and plastic, including recycled plastic. The pads may be reinforced near apertures used to secure the pad to the dumpster. The pads may include interior structure in addition to the flexible, durable primary pad material. The pads may have a substantially constant cross sectional configuration and may be manufactured by extrusion of appropriate material through a die, then cut to lengths suitable for a particular application. 
         [0015]    Accordingly, it is an object of the present disclosure to provide a pad for the roller shaped wheels and/or the runners disposed on the bottom of such containers that will survive the loads inherent in such large and heavy containers. 
         [0016]    It is another object of the present disclosure to provide pads that facilitate attachment of the pad to the wheels, runners and box tubes of a respective container when the container is elevated above the ground. 
         [0017]    It is yet another object of the present disclosure to provide an attachment means for the pads that will securely attach each pad to a respective wheel, or runner, or box tube. Attachment of the pad would be very difficult after the dumpster is set in place and setting the dumpster in place without the pad is likely to damage the paved surface under the container. 
         [0018]    It is a still further object of the present disclosure to provide a protective pad for the surface on which a dumpster is placed that can be securely attached to the dumpster during placement. 
         [0019]    It is still another object of the present disclosure to provide a protective pad that will expand the surface area upon which a dumpster is supported, reducing the local surface pressure and reducing the likelihood of damage to a paved surface beneath the dumpster. 
         [0020]    The recitation herein of desirable objects which are met by various embodiments of the present invention is not meant to imply or suggest that any or all of these objects are present as essential features, either individually or collectively, in the most general embodiment of the present invention or in any of its more specific embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The foregoing and other objects, features and advantages of the disclosed dumpster pads will be apparent from the following more particular description of illustrative embodiments, as shown in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the general structure and function of the disclosed dumpster pads. Those skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments. The features illustrated or described in connection with one exemplary embodiment can be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the appended claims. 
           [0022]    The disclosed dumpster pads may best be understood by reference to the following description taken in connection with the accompanying drawings, in which: 
           [0023]      FIG. 1  is a top view of a first embodiment of a dumpster pad configured to mount on a rail disposed at one end of a roll off dumpster; 
           [0024]      FIG. 2  is a perspective view of the pad illustrated in  FIG. 1 ; 
           [0025]      FIG. 3  is a side view of the pad illustrated in  FIG. 1 ; 
           [0026]      FIG. 4  is an end view of the pad illustrated in  FIG. 1 ; 
           [0027]      FIG. 5  is a sectional view of the pad of  FIGS. 1-4 , taken along the line  5 - 5  of  FIG. 4 ; 
           [0028]      FIG. 6  is a bottom view of a second embodiment of a pad in accordance with aspects of the disclosure installed on the wheel of a roll off dumpster; 
           [0029]      FIG. 7  is a side view of the pad of  FIG. 6  installed on the wheel of a roll off dumpster; 
           [0030]      FIG. 8  is a perspective view of the pad and wheel of  FIG. 7 ; 
           [0031]      FIG. 9  is an end view of the pad and wheel of  FIGS. 7, and 8 ; 
           [0032]      FIG. 10  is a partial perspective view showing one corner of a roll off dumpster and wheel to which is attached a pad of  FIGS. 6-9  in accordance with aspects of the present disclosure; 
           [0033]      FIG. 11  is a perspective view of a roll off dumpster view similar  FIG. 10  showing three roller wheels to which pads of  FIGS. 6-9  are attached; 
           [0034]      FIG. 12  is a side view of a dumpster pad according to aspects of the present disclosure; 
           [0035]      FIG. 13  is an end view of the pad of  FIG. 12 ; 
           [0036]      FIG. 14  is a bottom perspective view of the pad of  FIGS. 11 and 12 ; 
           [0037]      FIG. 15  is a top plan view of a third embodiment of a dumpster pad according to aspects of the present disclosure; 
           [0038]      FIG. 16  is a left end perspective view of the pad of  FIG. 15 ; 
           [0039]      FIG. 17  is a right end perspective view of the pad of  FIGS. 15 and 16 ; 
           [0040]      FIG. 18  is a side view of the pad of  FIGS. 15-17 ; 
           [0041]      FIG. 19  is a right end view of the pad of  FIGS. 15-18 ; 
           [0042]      FIG. 20  is a sectional view of the pad of  FIGS. 15-19 , taken along line F-F in  FIG. 19 ; 
           [0043]      FIG. 21  is a partial perspective view of a roll off dumpster supported at one end by ribs (one shown) in functional conjunction with a pad illustrated in  FIGS. 1-5 ; 
           [0044]      FIG. 22  is an enlarged partial view of the area B in  FIG. 21 , further illustrating the cooperation between the pad of  FIGS. 1-5  with the rib of the dumpster; 
           [0045]      FIG. 23  is a perspective view of a front load dumpster in functional conjunction with dumpster pads illustrated in  FIGS. 15-20 ; 
           [0046]      FIG. 24  is an enlarged partial perspective view of the area C of  FIG. 23 , showing in greater detail the pad of  FIGS. 15-20  supporting the dumpster; and 
           [0047]      FIG. 25  is a perspective view of a dumpster pad in conjunction with a box tube according to aspects of the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0048]    The present invention has application to small and large roll off dumpsters as well as front load dumpsters. The support structure for such dumpsters, also referred to herein as containers, differs for respective types of apparatus as well as the size of the apparatus. Roll off dumpsters of the larger sizes utilize a roller shaped wheel at each of the four corners. Smaller roll off dumpsters often utilize roller shaped wheels at one end and a pair of ribs or runners near the corners of the end opposite the wheels. 
         [0049]    A typical truck for placing a roll off dumpster carries the roll off dumpster with one longitudinal end of the dumpster extending beyond the body of the truck. The description of the elongated roll off dumpster herein will utilize the terms “inboard end” and “outboard end,” respectively, to refer to the end of the dumpster nearest the cab of the truck and the end of the dumpster furthest from the cab of the truck when the dumpster is being carried by the truck. When the dumpster is loaded onto the truck the wheels of the dumpster at the outboard end of the dumpster are accessible to allow mounting of pads in accordance with aspects of the present disclosure. Smaller roll off dumpsters typically are supported on heavy duty steel wheels at the outboard end and rails or runners at the inboard end. The type of dumpster determines the embodiment of dumpster pad that will be used. 
         [0050]    Three basic embodiments of a dumpster pad are shown.  FIGS. 1-5  illustrate a pad  14  configured for use in conjunction with the ribs/rails of the inboard end of a smaller roll off dumpster  10 , as shown in  FIGS. 21 and 22 .  FIGS. 12-14  disclose a pad  32  configured for use with wheels  30  of a roll off dumpster  50  as shown in  FIGS. 10 and 11 .  FIGS. 6-9  show the pad  32  of  FIGS. 12-14  mounted to a dumpster wheel  30 .  FIGS. 15-20  illustrate a pad  62  configured for mounting to the box tube at the bottom of a front load dumpster  60 , as shown in  FIGS. 23 and 24 . 
         [0051]      FIG. 21  illustrates an axial extremity of a dumpster  10  having a rail  12  extending down the face of the dumpster as well as along the bottom surface thereof. The rail  12  supports the dumpster  10 . A more detailed view is shown in  FIG. 22 . A first embodiment of the pad  14  in accordance with aspects of the disclosure is shown mounted to the rail in  FIGS. 21 and 22 . The pad  14  is further illustrated in  FIGS. 1-5 . Pad  14  includes a planar base  16  having transverse grooves  18  disposed at axially spaced intervals along the bottom surface of the pad  14 . The grooves  18  provide a pathway for water or other liquids that may flow at the job site, and to improve the grip of the pad  14  on a paved surface. 
         [0052]    Upstanding members  20 ,  22  are disposed in parallel spaced relationship to define a channel  21 . The spacing between the planar members  20 ,  22  defines the width W 1  of the channel  21  determined by the thickness of the rib  12 . Preferably the width of the channel  21  between the planar members  20 ,  22  provides a snug fit with the rib  12 . In the illustrated first embodiment as best seen in  FIGS. 2 and 4 , the base  16  has a width W 2  at least three times the width of the channel  21 , and preferably 3 to 5 times the width W 1  of the channel  21 . The thickness T 1  of the base  16  tapers from a maximum thickness beneath the channel  21  toward the edges of the base  16 . Force F on the base  16  may be used to open the channel  21  during installation of the pad  14  over the rib/rail  12 . The channel  21  may be narrower at its open end than at the base, to promote frictional engagement with the rib/rail  12 . 
         [0053]    A second embodiment of the pad  32  in accordance with aspects of the disclosure is particularly adapted for cooperation with roller shaped wheels  30 . The term roller-shaped is intended to convey that the width of the wheels  30  is commonly greater than the diameter, with the result that each wheel resembles a roller. The pads  32  are illustrated in  FIGS. 12-14  by itself, in  FIGS. 6-9  mounted to a wheel  30  and in  FIGS. 10 and 11  mounted to wheels  30  on a dumpster  50 . Each pad  32  includes a cylindrical recess  34  dimensioned and configured for snug engagement with the outside circumference of a wheel  30 . More particularly, a preferred embodiment of the pad  32  is dimensioned for snug engagement with more than 180° of the circumferential extent of the wheel  30 . It will be understood that the engagement with greater than 180° of the circumferential extent of the wheel  30  prevents inadvertent release of the pad. Accordingly, it will be understood installation of the pad  32  on the roller shaped wheel  30  must be accomplished by axial movement of the pad  32  with respect to the wheel  30 . The pad  32  has a generally planar base surface  36  that is also provided with transverse grooves  38  intended to provide a pathway for water or other liquids that may flow at the job site. The base surface  36  of the pad  32  has a width W 3  that is typically at least as wide as the roller shaped wheel  30  to which it is attached, and has a length L at least twice the diameter D of the wheel  30 . 
         [0054]    The pads  32  may be constructed of durable, flexible material that is relatively soft. Such materials include rubber, recycled tire material, plastic and recycled plastic, but the pads  32  may be constructed of any suitable materials or combination of materials. One useful attribute of the material would be flexibility, which would permit the recess to be “opened” slightly during installation over a wheel  30 . As shown in  FIG. 12 , force F at the ends of the pad  32  will bend the base at  33 , opening the mouth of the pad at  37  slightly, allowing the wheel to easily enter the cylindrical recess  34 . When force F is released, the flexible material returns to its original shape and grips the outside circumference of the wheel  30  as shown in  FIGS. 7 and 8 . 
         [0055]    The outer extremities of the pad  32 , as best seen in  FIG. 7  are rounded to minimize the possibility of damage to the paved surface on which the dumpster is installed. Some embodiments may include holes  39  disposed near the top as shown in  FIG. 7  to facilitate lashing the pad  32  to a wheel  30 . The holes  39  may be reinforced so that wires or hardware used to secure the pad  32  to the wheel  30  will not pull through the material of the pad  32 . Reinforcements include metal or plastic molded into or lining the holes  39 .  FIGS. 10 and 11  illustrate a dumpster  50  on which pads  32  are installed on roller shaped wheels  30 . The same material attributes and manipulation can aid in installing the first embodiment of pad  14  onto the rib  12  of dumpster  10 . See  FIGS. 4 and 22 . 
         [0056]    A pin or bolt  41  may be inserted through holes  39  as shown in  FIG. 9 . This provides a bar spanning a notch  43  in the pad  32 . The bar may be used as an anchor for a strap  60  with hook and loop material that can pass over the wheel  30 , under a pin or bolt  41  on the opposite side of the pad  32  and engaged to itself to secure the pad  32  to the wheel  30 . It is not intended that the pad  32  remain secured to the wheel  30  when the dumpster is in transit, but the strap  80  may be used to secure the pad  32  to the wheel while the dumpster is being dropped off. The strap  80  may be used to secure the pad  32  to rails running along the sides of the dumpster, to keep the pads securely attached during transit and keep them handy when needed. This arrangement also keeps the pads out of the cab of the truck, where they may not be permitted according to regulations. 
         [0057]    One important function of the pads  32  is to act as a “chock” for the wheel received in the pad  32 , not permitting the wheel  30  to roll along the paved surface onto which the dumpster is being installed. The sequence of actions for using the disclosed pads  32  is as follows. The driver/operator of the truck carrying a roll off dumpster approaches the location where the dumpster is to be lowered from the truck, and stops the truck. As previously discussed, the outboard end of the dumpster has two wheels  30  that are projected beyond the end of the truck and therefore accessible to the driver. The driver flexes a pad  32  as shown in  FIG. 12  and slides the pad  32  over the outside of the wheel  30  until the pad is centered on the width of the wheel, or at least until the entire cylindrical inside surface  34  of the pad is on the wheel  30 . This is done for both wheels  30 . The lowering process is begun by raising the hydraulically actuated bed and beginning to extend the cable or hook. The outboard wheels with pads attached touch the ground with the base  36  of the pads  32  contacting the paved surface first. The relatively soft material of the pad  32  forms a highly frictional engagement with the paved surface, while the cylindrical surface  34  prevents the wheel  30  from rolling. This situation results in a pivot point at the outboard wheels, with the weight of the dumpster tending to push the truck away from the pivot. Slowly releasing the cable or hook will allow the weight of the dumpster  10 ,  50  to effectively push the truck away from the dumpster in a controlled manner. Before the inboard end of the dumpster  10 ,  50  contacts the ground, the driver will need to install pads  14  or  32  to the inboard support of the dumpster, whether that is a rib/rail  12  or wheel  30 . The disclosed dumpster pads  14 ,  32  prevent movement of the dumpster supports over the paved surface, thereby preventing scraping or other damage during installation or removal. The dumpster pads also expand the surface area on which the dumpster is supported, reducing localized pressure and the likelihood of damage. Finally, pads  32  prevent rolling movement of a dumpster with four wheels, reducing the likelihood of a dumpster rolling from its installed location. 
         [0058]      FIGS. 15-20, 23-25  illustrate a pad  62  in accordance with a third embodiment according to aspects of the present disclosure. This embodiment has particular application to front load dumpsters  64  that are typically moved by two elongated forks that engage the side channels  42  of a dumpster  44  (see  FIG. 23 ). The front load dumpster  60  typically is provided with much wider support surfaces on the bottom face thereof in the form of open ended box tube members  90  (see  FIG. 25 ) that span the depth or width of the dumpster  60 . The dumpster  60  in  FIG. 23  has box tube support members extending from front to back (not shown).Those skilled in the art will recognize the term “box tube” to refer to tubing having a rectangular cross-section, the open ends of which define a rectangular opening (See ref. no.  90 ,  FIG. 25 ). 
         [0059]    The pad  62  is configured to close the open end of a box tube and extend a base beneath the box tube  90 , as shown in  FIG. 25 . The pad  62  includes upstanding parallel spaced apart members  64  that define a channel  65  for snug engagement with the outside surfaces of the box tube  90 . The channel  65  has a bottom surface  66  that abuts and supports the bottom surface of the box tube  90 . Thus, a trough shaped channel  65  is defined by the surface  66  and the upright members  64 . The trough shaped region is open at the right axial extremity (as viewed in  FIGS. 15-18 and 20 ). At one end of the channel  65 , a rectangular plug  68  is disposed in the channel  65  and connected to a toe  73  that closes the end of the channel  64  behind the plug  68 . The plug  68  is dimensioned to be received into the open end of the box tube  90 , with the base  76  of the pad  62  extending beneath the bottom surface of the box tube  90 . Accordingly, the pad  62  is installed by an axial movement wherein the plug  68  engages the box tube dumpster support and the toe of the pad closes the open end of the box tube as shown in  FIG. 25 . The plug  68  has a width that is compatible with the 3.5″ standard width of most box tubes used to support front loading dumpsters. The plug  68  has a height H that is compatible with the smallest vertical dimension of standard box tube, about 1″. The plug  68  is compatible with box tubes having a vertical dimension larger than about 1″ and so will fit most dumpsters. 
         [0060]    The base  76  may be configured to extend along a substantial length of the box tube, thereby providing a large surface area for the dumpster  60 . The bottom surface  77  of the pad  62  may include grooves for enhanced grip or allowing water to flow past the pads  62 . The pad  62  raises the dumpster by the height of the base  76 , so the box tube no longer touches the ground. This can help prevent rusting of the box tube and reduce the need for repairs. 
         [0061]    The upright members  64  of the pad may define holes  74  for hardware to secure the pad  62  on the box tube. The holes  74  may be reinforced with metallic inserts  72  running along either side of the channel  65 . Fasteners such as self-tapping screws may be used to secure the pad  62  to the box member. 
         [0062]    Although the description above contains many specifics, these should not be construed as limiting the scope of the invention, but as merely providing illustrations of some of the presently preferred embodiments of this invention. Thus, the scope of this invention should be determined by the appended claims and their legal equivalents. Therefore, it will be appreciated that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the present invention is accordingly to be limited by the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.”