Patent Publication Number: US-10766116-B2

Title: Hand-held sanding device with continuous rotating belt

Description:
FIELD OF THE INVENTION 
     The present invention relates to abrading tools and, more particularly, to a hand-held sanding device having a rotating sanding belt. 
     BACKGROUND OF THE INVENTION 
     When conducting woodworking and related crafts requiring a finished surface, a woodworker will oftentimes manually rub the surface of a work piece using a sheet of abrasive material, such as sand paper, to even out and smooth the surface. This can be a slow process, made more difficult because a sheet of sand paper can quickly wear out, and holding onto the paper while manually rubbing the piece can cause hand strain. Sanding blocks offer some improvement to sand paper. The blocks can be ergonomically shaped, and can hold larger pieces or sheets of sand paper. Additionally, sanding blocks include apparatus for holding the paper in place on the block. 
     Sanding blocks, however, also have several drawbacks. For instance, the paper on the sanding block tends to gum up or fill because the same area of the block is being repeatedly rubbed against the work piece. Stopping and cleaning the sand paper requires extra time, which is frustrating and inefficient. Additionally, the sand paper can easily rip because of the repeated wear in the same location. The sand paper also can easily rip if the paper is not held perfectly tight on the block. Having loose paper on the sanding block can also reduce the quality of the sanding done with the block and, thus, the quality of the finished work product. 
     Automatic sanders, either belt-type or orbital-type, can be easier to use, but they often provide more force than is necessary for the project, and can have a number of drawbacks. In particular, automatic sanders require a power source, necessitating the inconvenience of a power cord or the added weight of batteries. Automatic belt-type sanders also have the reputation of removing too much material too quickly. Orbital sanders are more commonly used, but can generate a lot of dust and also be too aggressive in removing material from the work piece. With fine woodworking, better results are typically achieved if the sanding is accomplished by hand, because hand sanding allows a much lighter touch than a motorized machine. 
     Accordingly, to facilitate fine woodworking, it is desirable to have a hand-held sanding device which is easy to use, and which eliminates the hand strain associated with sand paper. Additionally, it is desirable to have a hand-held sanding device which distributes the contact between the work piece and sanding material across a large surface area of the material, to prevent uneven wear, gumming up, or ripping of the material. Further, it is desirable to have a hand-held sanding device which holds the sanding material tightly on the device. Furthermore, it is desirable to have a hand sanding device which allows for easy removal and replacement of the sanding material, and which can operate without a secondary power source. 
     SUMMARY OF THE INVENTION 
     The present invention addresses the shortcomings of the prior art by providing a hand sanding device in accordance with several different aspects. According to a first aspect, the present invention provides a hand-held sanding device for sanding a work piece. The sanding device includes a frame adapted for a manual grip and a sanding material provided within the frame for movement relative to the frame. The sanding material forms a sanding surface for the device. The sanding material moves relative to the frame through contact between the sanding surface and the work piece. 
     In a second aspect, the invention features a hand-held sanding device having a frame and a plurality of rollers mounted within the frame. A sanding belt is trained over the rollers to rotate continuously with the rollers during a sanding operation. A tensioning member is provided for maintaining tension in the sanding belt as the belt rotates about the rollers. The tensioned belt forms a planar sanding surface for the device. 
     The above and other objects and advantages of the present invention shall be made apparent from the accompanying drawings and the description thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an exemplary embodiment of a hand-held sanding device of the invention; 
         FIG. 2  is a side view of the device of  FIG. 1 ; 
         FIG. 2A  is an exploded view of a roller end depicting an exemplary directional control scheme; 
         FIG. 3  is a perspective view of the device of  FIG. 1 , shown with the cover open and the sanding belt in phantom; 
         FIG. 4  is a top, cross-sectional view of the device of  FIG. 1 , taken along line  4 - 4  in  FIG. 2 ; 
         FIG. 5A  is a partial, side view of an alternative embodiment of the sanding device, showing a roller mounted at one end of the device frame; 
         FIG. 5B  is a cross-sectional view of the sanding device end shown in  FIG. 5A , taken along line  5 B- 5 B of  FIG. 5A ; 
         FIG. 5C  is an exploded, partial end view of the roller of  FIG. 5A , depicting an exemplary directional control scheme; 
         FIG. 6  is a partial, perspective view of a roller end showing a first exemplary latching assembly; 
         FIG. 7A  is a partial, sectional view showing an alternative exemplary latching assembly in a latched position; 
         FIG. 7B  is a partial, sectional view showing the alternative exemplary latching assembly of  FIG. 7A  moving to an unlatched position; 
         FIG. 8  is a side, partially sectional view of an exemplary embodiment of a directional control wheel for the sanding device; 
         FIG. 9  is a partial, perspective view of an exemplary sanding device depicting a manual control; 
         FIG. 9A  is a sectional view of the manual control taken along line  9 A- 9 A of  FIG. 9 ; 
         FIG. 10  is a side, diagrammatic view of an alternative embodiment of the sanding device depicting a hand positioned on the device and performing a sanding operation; 
         FIG. 11  is a side, diagrammatic view of an alternative embodiment of the sanding device depicting the device being used in a rotated orientation; 
         FIG. 12  is a side, diagrammatic view of an alternative, multiple roller embodiment of the sanding device with frame shown in phantom; 
         FIG. 13  is a side, diagrammatic view of a first, alternative, motorized embodiment of the sanding device with frame shown in phantom; 
         FIG. 14  is a side, diagrammatic view of a second, alternative, motorized embodiment of the sanding device with frame shown in phantom; 
         FIG. 15  is a side view of an alternative, multiple belt embodiment of the sanding device; 
         FIG. 16  is a perspective view of an alternative embodiment of the sanding device; 
         FIG. 17  is a side view of another alternative embodiment of the sanding device; and 
         FIG. 18  is a partial, side view of an alternative embodiment of the sanding device, with a portion of the device frame broken away to show a sanding tip. 
     
    
    
     The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the invention. 
     DETAILED DESCRIPTION 
     Referring now to the drawing figures, wherein like numerals indicate like elements throughout the views,  FIG. 1  illustrates a first exemplary embodiment of an abrading or sanding device  20 . As shown in  FIG. 1 , device  20  can be used to manually rub or scrape the surface of a work piece  22  to wear away roughness and smooth the piece. Sanding device  20  includes a frame  24  with rollers  30 ,  32  mounted at opposite ends. An abrasive material is provided within frame  24  for contact with the work piece. This material can be composed of any type of abrasive substance including, for example, sand, pumice, emery, etc., which produces friction when rubbed against an object in order to scrape or remove portions of the surface. In the embodiments described herein, the abrasive material is shaped into a continuous loop or belt  40 . Belt  40  is removably mounted on rollers  30 ,  32 , to rotate in conjunction with the rollers, as device  20  is drawn along the surface of a work piece  22 . 
     Belt  40  can vary in width, from approximately 1 inch to greater than 6 inches. Device  20  can be sized to accommodate standard belt widths such as, for example, 3 or 4 inches, to enable the device to be used with commercially available, “off the shelf” sanding belts. Additionally, the device frame  24  can be designed to be approximately the same width as the sanding belt, to enable the device to be used to sand into corners or up against raised edges. Rollers  30 ,  32  are biased outward within frame  24 , as will be described below, to hold belt  40  in a taut or tensioned condition between the rollers. The tensioned belt forms a planar sanding surface along the length of the device. A cover  42  is provided on frame  24  on the opposite side of the sanding surface, to form a hand grip above the belt  40 . As device  20  is drawn in a longitudinal direction along the work piece  22 , as indicated by arrow  26 , the contact between the belt  40  and the work piece  22  rotates the belt in the opposite direction, as indicated by arrow  28 . 
     As shown in  FIGS. 2-4 , device frame  24  of device  20  includes first and second sections  44 ,  50  that slide relative to each other. The frame sections each include a planar base, and side members extending in a perpendicular direction from opposite sides of the base. A first one of the rollers  30  is attached to one end of first frame section  44  by pins  34  extending out along the rotational axis of the roller. Pins  34  attach roller  30  between the side members of frame section  44 , to fix the roller position relative to the frame section, while allowing the roller to rotate within the frame. The second end of frame section  44  has longitudinally extending slots  46  formed therein. Slots  46  slidingly engage rotational axis pins  36  extending out along the rotational axis of the second roller  32 . The second frame section  50  also includes a pair of longitudinally extending slots  52  in the side members. Slots  46 ,  52  receive roller axis pins  36  to mount second roller  32  to the frame  24 . The mounting of pins  36  within slots  46 ,  52  enables roller  32  to rotate within the frame  24 , while also being moveable in a direction perpendicular to the rotational axis. Cover  42  is positioned over belt  40  on the side opposite the planar sanding surface. In the embodiment shown in  FIGS. 2-4 , the cover  42  is pivotally attached to a side of first frame section  44 . The cover is attached to an upper edge of the frame to pivot way from the belt  40  when opened, to allow access to the belt beneath. When pivoted closed, cover  42  extends over the belt  40  to provide a hand rest or grip above the rotating belt. 
     A tensioning member is mounted in frame  24  between rollers  30 ,  32 , for permitting movement of the frame sections  44 ,  50  relative to each other, while outwardly biasing the rollers in a spaced relationship. In the exemplary embodiment shown, the tensioning member is a resilient spring  60 . Spring  60  is mounted in frame  24  between first and second brackets  62 ,  64 , which extend vertically from the base of frame sections  44 ,  50 . First bracket  62  is attached to the first frame section  44 , and second bracket  64  is attached to the second frame section  50 . Spring  60  is mounted, in tension, between the inward facing, vertical extension of each bracket. The tension in spring  60  biases the brackets  62 ,  64  and, correspondingly, the attached frame sections  44 ,  50  apart, as shown by arrow  66  in  FIGS. 2 and 4 . The force of spring  60  drives the rollers  30 ,  32  outward, and pulls the belt  40  taut about the rollers. As roller  32  is biased outward by spring  60 , pin  36  slides to an inward-most position in slots  46 ,  52 , as shown in  FIGS. 2 and 3 . The spacing between rollers  30 ,  32  can be adjustable, by a screw or other mechanism, so that the tension or slack in the sanding belt can be set to the user&#39;s preference. In the tensioned condition, belt  40  may be pulled along the surface of a work piece to perform a sanding task. As belt  40  is pulled along the work piece, the frictional contact between the belt and work piece creates a secondary pulling force on the belt causing the belt and, in turn, rollers  30 ,  32  to rotate. As the belt  40  rotates, the area of the belt in contact with the work piece  22  continually changes. 
     To remove sanding belt  40  from the device, cover  42  is pivoted open to expose the belt. Opposing forces are applied to rollers  30 ,  32  to push the rollers inward towards each other. The opposing forces can be applied by positioning a hand over each of the rollers and pushing inward. The opposing, inward force on rollers  30 ,  32  compresses spring  60 . The inward force on rollers  30 ,  32  slides pins  36  within slots  46 ,  52  as the spacing between the rollers decreases. As rollers  30 ,  32  move inward the tension in belt  40  is relaxed, allowing the belt to be pulled or slid off of the rollers. A replacement belt can be positioned over rollers  30 ,  32 , and the inward force on the rollers released, to allow spring  60  to return the rollers to an outwardly-biased position, with the belt  40  held taut between the rollers. As spring  60  moves rollers  30 ,  32  outward, roller pins  36  move to an inner-most position in frame slots  46 ,  52 . 
     To facilitate a belt change, a latching mechanism can be included in frame  24  for holding rollers  30 ,  32  and spring  60  in an inward, compressed position, while the used belt is removed from the rollers and a replacement belt mounted over the rollers. The latching mechanism can be automatic, with the latch being set when rollers  30 ,  32  are first compressed together, and released with a second compression of the rollers to move the rollers outward and return the belt  40  to full tension. A number of different types of latching mechanisms may be used to hold the rollers in a compressed position including a cam mechanism, a catch mechanism or a roller catch, for example. 
     Alternative device  20   b  utilizes one exemplary latching mechanism as illustrated in  FIG. 6 . This latching mechanism uses a push button style latch. A hole is formed through first frame  44   b  and a flexible button latch  54  is formed into second frame section  50   b . Slots  56  in frame  50   b  allow the button latch  54  to flex in and out of the hole in frame  44   b  to lock the frame sections together. An alternative, exemplary latching mechanism is illustrated in  FIGS. 7A and 7B . In this embodiment, a flexible button latch  94  is attached by a fastener  96  on the inside of frame section  50   c . Button latch  94  can be flexed in and out of holes  98 , formed in frame sections  44   c ,  50   c , as shown in  FIG. 7B . Button latch  94  is normally disengaged from holes  98  to allow spring  60  to bias rollers  30 ,  32  to an outward position. For a belt change, rollers  30 ,  32  can be pushed inward until button latch  94  engages the aligned holes  98 , as shown in  FIG. 7A , to hold the rollers in the inward position. After the belt change, button  94  can be pushed out of holes  98 , as shown in  FIG. 7B , to allow the rollers to return to an outward-biased position. 
     In the exemplary embodiment shown in  FIGS. 1-4 , belt  40  is rotated in a single direction by rollers  30 ,  32 . Single direction rotation provides a more natural hand motion for a sanding operation, while continually changing the position of the belt to provide even wear of the belt and better sanding quality. A number of different mechanisms can be implemented in device  20  to control the direction of rotation of belt  40 . In a first embodiment, shown in  FIG. 2A , directional control is provided by a pair of disks  70 ,  72  turning against each other at the ends of one or both of the rollers  30 ,  32 . The first disk  70  is fixed to frame section  50 , and includes a plurality of radially-spaced holes  74  concentrically spaced about the rotational axis pin  34  or  36 . The second disk  72  is fixed to the inner diameter of the roller  30  or  32 , and includes a plurality of radially-spaced stops  76 , also concentrically spaced about the rotational axis pin  34  or  36 , and extending perpendicular to the planar face of the disk. Stops  76  are spaced to fit within holes  74  as the two disks rotate.  FIG. 4  shows a stop disk  72  positioned at opposite ends of both rollers  30 ,  32 , with a first disk  70  positioned over the stop disk. The contact between the stops  76  and the holes  74  limits the relative movement of the disks, permitting rotation of the disks and, thus, the rollers  30 ,  32 , in only one direction. 
     Another exemplary form of directional control can be provided by using one-way or directional bearings in rollers  30 ,  32 . The directional bearings may be mounted on the rotational axis of one or both rollers  30 ,  32  to allow roller rotation in only one direction. Additionally, the rotation direction of belt  40  can be controlled by a third wheel or axle device positioned in contact with the outer surface of the belt.  FIG. 8  illustrates an exemplary embodiment of a sanding device  20   c , in which directional control is provided by a third wheel  116 . In this embodiment, the third wheel  116  contacts the outside of sanding belt  40  through pressure from a tensioning member  124 . Tensioning member  124  extends between a first bracket  126  attached to cover  42 , and a second bracket  128  attached to the axis of wheel  116 . Wheel  116  is biased into contact with belt  40  by the force of the tensioning member  124  between the wheel and cover  42 . Wheel  116  tensions belt  40  when cover  42  is closed and the tensioning member  124  is compressed. The rotational direction  134  of wheel  116  is opposite of the rotational direction  28  of belt  40 . In device  20   c , rollers  30 ,  32  are drawn closer together than in the previous embodiment  20 , due to the pressure of the third wheel  116  on belt  40 , enabling the device to have a shorter longitudinal length compared to device  20  for the same length sanding belt  40 . Rollers  30 ,  32  are free spinning on the inner circumference of the belt  40 , while the third wheel  116  provides directional control to the outside of the belt. In addition to the described methods, it is envisioned that numerous other methods and apparatus known in the art may be used for providing directional control of belt  40 . 
     Additionally, instead of limiting rotation to one direction, the sanding device can include directional controls to allow unencumbered or unrestricted rotation in one direction, and limited rotation in the reverse direction. Allowing limited rotation in the reverse direction can reduce wear on the sanding belt during light sanding operations. The limited movement in the reverse direction can be accomplished using manual control. An exemplary sanding device  20   d  having a form of manual control is illustrated in  FIGS. 9 and 9A . In device  20   d , manual control is provided through a flexible tab  136  formed into cover  42   b . Tab  136  can be flexed by a finger in a downward direction into contact with belt  40 . As shown in  FIG. 9A , a pad  138  may be provided on the end of tab  136 , and secured by an interference or snap fit, to increase friction between the tab and belt  40 . The friction created by contact between tab  136  and belt  40  controls the slippage of the belt. The pressure applied to tab  136  can be varied to slow or completely stop belt rotation, thereby enabling the user to control which section of the belt contacts the work piece, and providing an increased sense of control during use, as well as prolonging belt life. 
     In an alternative embodiment, shown in  FIGS. 5A and 5B , the sanding device can be designed, as indicated at  20   a , so that the frame is the same width as the sanding belt. Altering the device frame, as indicated by frame  24   a , enables the rollers  30 ,  32  to have a width that is less than at least part of the frame  24   a , including sections  44   a  and  50   a . The reduced width of the rollers  30 ,  32  and frame  24   a  relative to the belt  40 , allows the sanding device to be maneuvered into a corner of a work piece  22 , as shown, to enable sanding in a corner or up against a raised edge.  FIG. 5C  illustrates a directional control scheme similar to  FIG. 2A , for the device embodiment shown in  FIGS. 5A and 5B . As shown in  FIGS. 5B and 5C , directional control can be provided for the reduced frame width, by a pair of disks  70   a ,  72  turning against each other at the ends of one or both rollers  30 ,  32 . The first disk  70   a  which is positioned between frame section  50   a  and disk  72 , includes a plurality of radially-spaced holes  74  concentrically spaced about the rotational axis pin  34  or  36 . The second disk  72  includes a plurality of radially-spaced stops  76 , also concentrically spaced about the rotational axis pin  34  or  36 , and extending perpendicular to the planar face of the disk. Stops  76  are spaced to fit within holes  74  as the two disks rotate. As shown in  FIG. 5B , the stop disk  72  is positioned at opposite ends of roller  32 , with the first disk  70   a  positioned over the stop disk. The contact between the stops  76  and the holes  74  limits the relative movement of the disks, permitting rotation of the disks and, thus, the rollers, in only one direction. 
     In other exemplary embodiments, the shape and/or structure of the device frame can be modified to incorporate additional features for the sanding device. For example, the shape of the device frame may be modified, as shown at  24   b  in  FIG. 10 , to form a more ergonomic hand grip for the device. Device  20   e , as shown in this embodiment, can have a raised cover  42   c  and an asymmetric shape, with a thumb recession on one side and finger recessions on the other. With an asymmetric shape, the rotation direction of the belt is preferably reversible to prevent user fatigue from holding the device in the same manner. Alternatively, device  20   e  can have generic recessions on both sides of the cover  42   c  to allow the device to be turned around and used to sand in the opposite direction. In addition, it is envisioned that at least a portion of device  20   e  could be composed of a plastic material that is malleable when heated, to enable the device to be customized to an individual user&#39;s hand. 
     In another alternative embodiment, shown as device  20   f  in  FIG. 11 , cover  42   d  can have a flat surface and include a layer of anti-skid or tacky material  80  on the outside of the cover. The layer  80  could, for example, be composed of a thermoplastic polyurethane or silicone rubber. The device can then be flipped over and used in an upside-down position as a stationary sanding tool. The anti-skid layer  80  on cover  42   d  will hold the device in place on a flat surface, such as a work table  82 . In this position, belt  40  can be advanced as desired, either manually or through contact with a work piece  22 , to clear dust, and prevent excessive wear on any one section of the belt. 
     As mentioned above, belt  40  can have varying widths to accommodate a number of different types of projects. Additionally, belt  40  can have varying lengths, with the length of the device varying to accommodate the different belt lengths. As shown in  FIG. 12 , the sanding device can also be modified, as shown by device  20   g , to include more than two rollers and, thereby, accommodate a longer length belt. Belt  40  can be trained over the additional rollers  84 ,  86 , and  90 , to remain taut within device  20   g , while rotating through a planar sanding surface  92  along the bottom length of the device. Using a longer belt in this manner can extend the period of use between belt changes. To replace the belt  40 , rollers  30 ,  32  can be compressed inwardly, as described above, to release the tension in the belt, and enable the belt to be slipped off of the multiple rollers and replaced. In embodiments having numerous rollers, the device frame may be modified, as indicated by  24   c , to encompass the additional rollers while still providing a comfortable hand grip for operating the device. 
     While the sanding device has been described above as being a manual sanding device in which the sanding belt is continuously rotated through frictional contact between the belt and work piece, the device can optionally also include a motor for powering the belt directly, or powering one or more of the belt rollers. As shown in  FIG. 13 , a modified sanding device  20   h  includes a motorized drive wheel  100  mounted in contact with belt  40  inside frame  24   d . A motor mounted inside the wheel  100  can drive the wheel to rotate belt  40  through frictional contact between the belt and wheel. Alternatively, as shown in  FIG. 14 , one or more motorized drive wheels  106  can be provided within a modified device  20   i , inside frame  24   e , for providing direct drive to either belt  40 , one or more rollers  30 ,  32 , or directly to both the belt and rollers. One or more motors  102  could be mounted in frame  24   e  above belt  40  as shown. The motors  102  can rotate a drive belt  104  and wheel  106  in contact with the belt  40 . Optionally, as shown in phantom, motors  102  may be connected via a drive belt  104  to one or both rollers  30 ,  32  (only a connection to roller  30  is shown) for providing a direct drive of one or both rollers. The motors  102  may be powered by batteries  108 , or an alternative, internal or external power source. 
     In another exemplary embodiment, the sanding device may be modified to include more than one sanding belt and roller pair unit. Each of the individual sanding belt units can be constructed as described above to enable the individual belts to be tensioned between the roller pairs, and each of the roller pairs retracted inward, as needed, to release and replace the belts. As shown in  FIG. 15 , in this embodiment of a device  20   j , multiple sanding belts  40  may be rotated in the same direction, as indicated by the arrows  110 ,  112 , to increase the effective length of a work piece that can be sanded at one time. Increasing the number of sanding units within the device provides for a longer planar sanding surface, while maintaining the same standard belt loop size as a single belt unit. Alternatively, the multiple sanding belts may be rotated in opposite directions, as indicated by arrows  110  and  114 , using a directional control mechanism as described above. Rotating the two belts in opposing directions allows for bi-directional sanding. Using multiple sanding belts  40 , as in exemplary device  20   j , will allow for faster sanding of large work pieces. Also, the longer sanding surface  92  provided by multiple sanding units will be more effective at flattening the surface of a work piece, because the larger contact area will even out high and low spots. In this embodiment, cover  42   e  can be altered to include additional handles, such as a hand grip  120  and palm grip  122 , similar to a woodworking plane. The device can also include one or more pads on cover  42   e  (not shown) to provide cushioning for the user&#39;s arms on the longer device. 
     In yet another alternative embodiment, shown in  FIG. 16 , the sanding device can be modified, as shown in device  20   k , to incorporate a vacuum attachment  130  for suctioning out dust produced during a sanding operation. Vacuum attachment  130  can connect to cover  42   f  at a position away from the hand grip so as to not interfere with use of the device. Vacuum attachment  130  can be connectable to a standard wet/dry vacuum system for removing dust from the sanding belt as the belt rotates beneath the cover. Alternatively, device  20   k  can incorporate a manual catcher bag or canister (not shown), and one or more vacuum ports beneath cover  42   f , to accumulate the sanding dust and debris. The canister can be periodically emptied during a sanding operation to control the dust. 
       FIG. 17  depicts another alternative embodiment, identified as device  20   l , in which the shape of the device frame is modified to provide a curved sanding surface  132 , rather than the planar sanding surface  92 . The curved surface  132  shown in  FIG. 17  provides for easier sanding of curved work pieces. In addition to the convex sanding surface shown in  FIG. 17 , it is envisioned that frame  24   f  may also be modified to provide a concave sanding surface. 
     As shown in  FIG. 18 , in another alternative embodiment, identified as device  20   m , the device is modified so that frame section  44   c  include a sanding tip  140  having a sharper radius than the radius of rollers  30 ,  32 . The sharper radius can be achieved using a formed and rigid material, such as steel, positioned between one or both of the rollers  30 ,  32  and the belt  40 . The tip  140  can extend between side members of modified frame section  44   c . Tip  140  can be located so as to allow belt  40  to rotate about the tip during the continuous rotating motion. Sharpened tip  140  can be used to reach into corners, as shown, or other intricate areas of a work piece  22 . 
     The present invention has been described in connection with several embodiments and some of those embodiments have been elaborated in substantial detail. However, the scope of the invention is not to be limited by these embodiments which are presented as exemplary and not exclusive. The scope of the invention being claimed is set forth by the following claims.