Patent Publication Number: US-2007101909-A1

Title: Work surface cover

Description:
This application is directed to protective elements, and in particular, to a cover for a work surface.  
     BACKGROUND  
      Many tools in home and professional settings have a table (or table-like) work surface, i.e., a relatively large and generally flat surface that is typically, although not necessarily, oriented horizontally. Examples of tools with such a work surface include table saws, joiners, band saws, drill presses, sanders and planers, to name a few.  
      These tools are generally expensive and intended to have a long life. To maintain their effectiveness, the work surfaces must be in good working order so that workpieces can be moved easily and any dimensional relationships are maintained. For example, owners strive to keep the work surfaces free from surface damage such as dents, gouges, pitting, stains, abrasions, etc.  
      Damage can occur from contact with other objects, such as dropped objects, or while using the work surface for other purposes. Damage can also occur from exposure to environmental conditions, such as high humidity. Roof leaks and spills also account for damage.  
      For some precision work surfaces, such as table saw surfaces, owners attempt to protect the work surface by applying a preparation such as Boeshield T-9, which is said to dry to a thin waxy film that clings to metal.  
      Separate covers for tools are known, but they suffer from one or more of the following drawbacks. Some covers, such as those made of highly flexible plastic sheeting, may be effective against dust and spills, but are cumbersome and time consuming to install and to remove. Such covers are often cumbersome to store when they are not in use. In addition, such covers generally prevent any use of the work surface while they are in place over the work surface. For example, highly flexible plastic covers tend not to fit closely to the work surface.  
      In many shop environments, space is limited, so adapting a work surface on a dedicated tool such as a table saw for use as an adjunct work space would also be advantageous.  
     SUMMARY  
      Described below is a cover for a work surface that overcomes some of the problems of the prior art covers.  
      According to one embodiment, a cover for a work surface comprises a cover member having an outer surface and an opposite inner surface. The cover member is shaped to overlie a work surface and to be removably securable to the work surface by an attractive force between the inner surface and the work surface.  
      The attractive force between the inner surface and the work surface can comprise a magnetic force, a static attraction force and/or a force resulting from adhesion. The attractive force can be sufficient to couple the inner surface to the work surface and resist damage to the work surface caused by high humidity environments. The attractive force can substantially reduce intrusion of fluid or vapor between the cover member and the work surface, thereby reducing damage to the work surface.  
      The cover member can comprise a sheet of flexible magnetic material. The cover member can be formed of flexible magnetic sheet material, with the upper surface being self-healing to resist damage from serving as a cutting surface and the lower surface being magnetic. The cover member can be formed of flexible magnetic sheet material comprising ferro magnetic powder mixed with a polymer bonding.  
      The cover member can provide impact resistance to reduce the effect of impacts to the work surface.  
      The outer surface of the cover can be imprinted with indicia. The indicia can include at least one measurement graphic positioned for use in relation to an edge of the work surface such that when edges of the cover are aligned with edges of the work surface, the work surface edge can be used in taking a measurement using the measurement graphic.  
      In some embodiments, the cover member can be rolled for transport and/or storage. In some embodiments, the cover member is electrically insulative relative to the work surface.  
      In some embodiments, the inner surface of the cover member comprises at least one surface leveling feature corresponding to a protruding or depressed work surface feature, and the surface leveling feature is shaped to fit together with the work surface feature such that the upper surface is substantially flat when cover member is in place on the work surface. For example, the work surface feature can be a groove, and the at least one surface feature can be a rib extending from the inner surface of the cover member and shaped to fit within the groove when the cover member is in place on the work surface. Instead of or in addition to leveling, the feature(s) may assist in aligning the cover with the work surface.  
      The cover can include at least one opening defined in the cover member. The cover member can be provided with a cut-out extending inwardly from a periphery of the cover, the cut-out allowing portions of the cover adjacent the cut-out to be moved relative to each other to assist in positioning the portions laterally adjacent an object extending from the work surface.  
      The cover can be shaped such that the outer surface protrudes beyond the inner surface over at least a portion of a periphery of the cover.  
      According to a representative method of preventing environmental damage to a work surface, a work surface is provided, a work surface cover sized to overlie at least a portion of the work surface is provided, and the work surface cover is positioned on the work surface and removably secured to the work surface by an attractive force exerted between the work surface cover and the work surface. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a perspective view of an embodiment of a work surface cover.  
       FIG. 2  is a top plan view of the work surface cover of  FIG. 1 .  
       FIG. 3  is a front side elevational view of the work surface cover of  FIG. 1 .  
       FIG. 4  is a cross-sectional elevational view of the work surface cover taken along the line  4 - 4  in  FIG. 2 .  
       FIG. 5  is a magnified view of a portion of the cross-section of the work surface cover of  FIG. 4 .  
       FIG. 6  is a perspective view of a typical tool having a work surface and showing the work surface cover ready to be installed.  
       FIG. 7  is a perspective view similar to  FIG. 6 , except showing the work surface cover in the process of being placed in contact with the work surface.  
       FIG. 8  is a perspective view similar to  FIGS. 6 and 7 , except showing the work surface cover fully positioned in contact with the work surface.  
       FIG. 9  is a magnified perspective detail view showing a corner of the work surface cover according to one embodiment.  
       FIG. 10  is a plan view of a work surface cover according to another embodiment in which the work surface cover is provided with various measurement, calculation and information indicia.  
       FIG. 11  is a plan view photograph of a test section of work surface material showing a generally uniform surface with only minor variations and no oxidation.  
       FIG. 12  is a plan view photograph of the test section of  FIG. 11  after a work surface cover has been placed on a right portion of the test section, the left portion remaining uncovered, before the test portion is subjected to a high humidity environment.  
       FIG. 13  is a perspective view photograph of the testing apparatus within which the test section of work surface and work surface cover of  FIG. 12  were subjected to a high humidity environment.  
       FIG. 14  is a plan view photograph of the test section of  FIG. 12  following exposure to the high humidity environment, showing that the uncovered left portion of the test section developed substantial oxidation.  
       FIG. 15  is a plan view photograph of the test section of  FIG. 13 , except with the work surface cover removed from the right portion, showing that the right portion is comparatively free from oxidation compared to the left portion.  
       FIG. 16  is a perspective view showing another embodiment of a cover being installed for use with a band saw.  
       FIG. 17  is a perspective view similar to  FIG. 16 , except showing the cover installed on the work surface of the band saw. 
    
    
     DETAILED DESCRIPTION  
       FIGS. 1-5  show a representative embodiment of a work surface cover  10  that is removably securable to work surface (such as a work surface W as shown in  FIGS. 6-8 ) to protect the work surface from damage and to provide additional functionality to the work surface. The work surface cover is removably securable to the work surface by an attractive force between the cover and the work surface, as is explained in more detail below.  
      The work surface cover protects the work surface in several ways. First, the cover provides protection against damage to the work surface from contact with other objects, such as from inadvertently dropped objects, from blades or other cutting edges, or other incidental contact. Second, the cover provides protection against environmental damage, including oxidation caused by presence of the work surface in a high humidity environment and/or liquid contacting the work surface (e.g., from a roof leak, a spill, etc.).  
      The work surface cover  10  is comprised of a cover member  12  shaped to cover at least a portion of the work surface. The work surface may be oriented generally level, or it may have any other orientation, including a vertical orientation. The work surface cover may be sized to cover substantially all of the work surface area, or a portion of the work surface area. Two or more separate work surface covers may be used in conjunction with each other to cover all or a portion of the work surface.  
      The cover member  12  generally has an outer surface  14  and an opposite inner surface  16 . The cover member  12  has a periphery defined by at least one edge. In the embodiment of  FIGS. 1-5 , the cover member has a generally rectangular periphery defined by a pair of opposing major edges  18  and a pair of opposing minor edges  20  that connect the major edges  18 . The cover member  12  may have a periphery with a continuously curving edge or one or more curved edges together with one or more straight edges.  
      In  FIGS. 1-5 , the major edges  18  and the minor edges  20  intersect at corners  22 , which may be relatively sharp as shown in  FIGS. 1-5  or radiused as shown in  FIG. 10 . The corners  22  may have any other suitable configuration, such as the overlapped configuration as shown in  FIG. 9 , or a mitered or beveled configuration.  
      Optionally, the cover  10  may have at least one surface leveling feature  24  that cooperates with a corresponding feature of the work surface, such as a protrusion or depression, when the cover is in place to provide a substantially flat work surface. For example, the inner surface  26  can be provided with ribs  26  shaped to fit within grooves on the work surface (see, e.g., the grooves G in  FIGS. 6-8 ). When the cover member  10  is placed on the work surface with the ribs  26  received in the grooves, the resulting covered work surface is more resistant to deformation in the areas overlying the grooves because the ribs occupy these voids. This can be advantageous for certain uses of the covered work surface, such as if even force must be applied across the work surface. Instead of or in addition to leveling, the feature(s) may assist in aligning the cover with the work surface.  
      As stated, the cover  10  is removably secured to the work surface by an attractive force between the cover and the work surface. More specifically, the attractive force exists when the inner surface  16  is in contact with the work surface. The attractive force is sufficient to maintain the cover  10  in its desired position, such as e.g., with its edges aligned with edges of the work surface during normal use of the cover. Such normal use of the cover includes simply covering the work surface, providing a place to store objects without having them directly contact the work surface, and/or serving as an active adjunct work space, e.g., for layout, assembly, or other typical workbench activities. The attractive force tends to keep the cover  10  in place when it is subjected to shearing forces encountered in typical workbench activities, yet the cover is easily removable from the work surface by separating one of its edges from the adjacent work surface edge and pulling the cover away.  
      According to one embodiment for use with a work surface made of or comprising a magnetic material, the cover  10  is provided with a magnet portion, such as, e.g., a magnetic inner surface  16 , such that a magnetic force is generated between the cover  12  and the work surface when the inner surface  16  is placed on or very close to the work surface.  
      According to some embodiments, the cover member  12  is flexible so that it conforms to the work surface. In some embodiments, the cover member  12  is sufficiently flexible to be rolled up, e.g., to provide for convenient storage and transport.  
      Suitable materials for the cover  10  include commercially available magnetic sheet material. Magnetic sheet material typically comprises ferro magnetic powder mixed with a polymer bonding. In one embodiment, the preferred material is High Energy Flexible Magnet sheet having a width of about 1020 mm and a thickness of 0.4 mm, which is available from Magmate Taiwan Ltd. of Taoyuan County, Taiwan http://www.magmate-magnets.com/) in 10 m rolls. Such material tends to be self-healing when subjected to minor cuts from a blade, yet can be easily formed to a desired shape by hand (such as with scissors). The outer surface tends to be non-stick and is relatively easy to clean. This material can also be rolled, e.g., for transport and storage.  
      According to other embodiments, the attractive force is a static attraction force. In these embodiments, the cover can be made of a statically attractive material such as static label material, and the work surface is susceptible to such a static attraction.  
       FIGS. 6-8  show the cover  10  being deployed to protect the work surface W, which in this case is the table portion of a table saw T. The cover  10  is also shown in position above the work surface W, e.g., after it has been unrolled or unfolded from a storage position. As shown in  FIG. 8 , the grooves G and a blade opening B interrupt the work surface W, making it inconvenient for use as an adjunct work space. In  FIG. 7 , the cover  10  has been placed in contact with the work surface W, with the edges of the cover  10  aligned with those of the work surface W, beginning at the left side of the cover as seen in the figure. In  FIG. 8 , the cover  10  is shown in its installed position on the work surface W and held in contact by an attractive force. Thus, with the cover  10  in place, the work surface W is protected and an adjunct work space relatively free of interruptions is provided.  
       FIGS. 16-17  show a cover  10  shaped for the table portion of a band saw and having an opening  28  allowing the cover  10  to be installed while the band saw blade remains in its normal operating position. As shown in  FIGS. 16-17 , the opening  28  is a slot extending from one of the edges of the cover  10 , which allows the portions of the cover on either side of the slot to be moved relative to each other to allow the cover to be installed with its edges aligned with those of the work surface W. In other applications, other openings, such as one or more through openings that do not extend to an edge of the cover  10 , may be provided.  
      Optionally, the cover member  12  can include indicia, such as one or more graphics  38 . Examples of several such graphics  38  are shown in  FIG. 10 . The graphics  38  may be workplace aids, such as measurement guides, reference tables, etc. For example, the cover member  12  includes a protractor guide  40  having a horizontal (0 degree) axis  42  positioned at one of the major edges  18  and a perpendicularly extending vertical (90 degree) axis  44 . In the example shown, the horizontal axis  42  and the vertical axis  44  are also ruler axes having graduations for measuring length. A second angle measurement guide, e.g., an angle guide  46 , can also be provided.  
      In some embodiments, one or more of the measurement guides are positioned at or near the edges of the cover member  12  such that the when the cover  10  is installed on the work surface W and the respective edges are aligned, the edges of the work surface W can be used in conjunction with the measurement guides in taking measurements. For example, the angle guide  46  can be used to set the desired angle for a bevel guide tool angle by pressing the handle of the tool against the adjacent edge of the work surface, aligning the movable blade with the desired angle on the angle guide  46  and then securing the blade in place. Also, the vertical axis  44  can be conveniently used to measure a workpiece or other object having a near end held flush against the nearest edge  18  of the work surface W. As another example, the measurement guides can be used in conjunction with a T-square or other similar implement that contacts an edge of the work surface W as a reference point. After installation, the cover  10  remains stationary relative to the work surface W in normal use, so having the measurement guides on the cover member  12  eliminates the need to hold a separate ruler or separate protractor in place relative to the work surface W, and relative to the piece of stock or other object, at the same time.  
      The graphics  38  can include other types of information useful for the work environment, such as tables and/or guides for trigonometric conversion, unit conversion, decimal conversion, drill sizing, wood and board information, geometry, etc. Any other suitable indicia may also be provided on the cover member  12 , either by imprinting or other appropriate method.  
       FIGS. 11-15  show the results of testing conducted to evaluate the work surface cover&#39;s capability to protect the work surface from environmental damage. As shown in  FIG. 1 , a test section  50  of a typical work surface material, e.g., a hot-rolled steel was provided in a conveniently sized rectangular shape. As shown in  FIG. 11 , the test section  50  is generally uniform but exhibits minor variations in color over its surface, as is typical in steel. No oxidation is present on the surface of the test section  50 .  
       FIG. 12  shows the test section  50  with a work surface cover  52  covering its right portion  54 , its left portion  56  remaining uncovered. The areas of the right portion  54  and the left portion  56  are approximately equal.  
      The test section  50  with the cover  52  as shown in  FIG. 12  was subjected to a high humidity environment, e.g., approximately 90% RH, for one day to evaluate the effects of that environment on the covered right portion  54  versus the uncovered left portion  56 . As shown in  FIG. 13 , the test section  50  with the cover  52  was placed in a container  58  (the container is shown in  FIG. 13  with its lid removed for clarity). A small electric humidifier  60  was positioned approximately as shown to heat the environment in the container. A battery-powered humidity meter  62  was positioned approximately as shown to monitor the humidity level within the closed container  58  during testing. One suitable humidifier for testing purposes is the Windchaser MH-2 Ultrasonic Humidifier.  
      Following exposure for one day to the high humidity conditions in the container  58 , the test section  50  was removed, allowed to dry and inspected. Before drying, the covered right portion  54  was “beaded up,” i.e., covered with discrete water droplets. As shown in  FIG. 14 , the uncovered left portion  56  developed substantial oxidation in a familiar rust cover. Such oxidation roughens the surface of the work surface. There was no apparent change to the outer surface of the cover  52 .  
      The cover  52  was then removed from the right portion  54 , as shown in  FIG. 15 . As shown, the right portion  54  of the test section is substantially free from oxidation. Along a line separating the right portion  54  from the left portion  56 , some very minor oxidation has occurred, probably because of “bleed through” from the left portion. This very minor oxidation is confined to the immediate intersection where the uncovered portion meets the covered portion and is lighter in color and much less expansive than the oxidation that developed over the entire uncovered left portion.  
      Thus, the testing showed that even under extreme humidity conditions, the cover provided substantial protection to the work surface when compared to the oxidation that developed in the same conditions on an uncovered portion of the same work surface.  
      In  FIGS. 6-9 , the cover  10  is shown in use with a table saw. Standard full size table saws typically have a “table” or work surface area of 27 inches by 40 inches. Thus, if the cover  10  is intended to cover the entire work surface and is made in a single piece, the cover  10  will have similar dimensions of about 27 inches by 40 inches. It is of course to provide a cover of less than the total work surface area.  
      If desired, the cover can made of a material that is electrically insulating relative to the work surface, e.g., such as the steel table portion of a table saw. In this way, with the electrically insulative cover in place, the resulting work space can be used for electronics assembly or for other activities where a non-conducting work surface is preferred.  
      Although many of the above examples refer to a table or table portion associated with a tool, the work surface cover can of course be used with other types of work surfaces, such as the work surface of a general use table. For example, the cover can be adapted for use with a table such as a granite metrology table. In addition, the work surface may be a portion of a hand tool, e.g., a block plane.  
      In view of the many possible embodiments to which the principles of the disclosed herein may be applied, it should be recognized that the illustrated embodiments are only preferred examples and should not be taken as limiting in scope. Rather, the scope is defined by the following claims. I therefore claim as my invention all that comes within the scope and spirit of these claims.