REFERENCE TO RELATED APPLICATION  
       [0001]    The present application is a Continuation in Part to the equally titled U.S. patent application filed Apr. 19, 2001, application Ser. No. 09/839,567, which is hereby incorporated by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates generally to panels for use with rack units. More particularly, this invention relates to blank panels comprised of face plates and means for attachment to open and enclosed electronic rack units.  
         BACKGROUND ART  
         [0003]    Known blank panels for use with electronic rack units are typically composed of face plates having a rectangular cross section with elongated holes positioned in proximity to the outer edges for receiving fasteners to facilitate attachment to rack units. The face plates and associated holes are dimensionally sized and configured to standards set by the Electronic Industries Association (EIA). In EIA Standard RS-310-C the dimensional standards for racks, panels, and associated equipment are specified. Three cabinet and rack widths to accommodate each of three standard panel widths, 19″, 24″, and 30″ are covered by this Standard. 19″ is the preferred width. Panel height is defined by the Standard in multiples of Rack Units (RU&#39;s). One Rack Unit is defined as 1.75″.  
           [0004]    Blank panels are typically employed on rack units for either aesthetic or enclosure purposes. A blank panel is often used to keep contaminants (such as dust) out of a rack unit and away from sensitive equipment. Rack units also often employ forced or drawn air ventilation systems to cool components. These systems require a substantially closed system to maintain proper convection flows. Open panels on the front of rack units compromise the effectiveness of these systems. Blank panels are often used to cover vacancies in the front of such rack units.  
           [0005]    Blank panels are used extensively in conjunction with various types of rack units. Specific terminology extends to blank plates, blank panels, and face plates among others. Blank panels, as used in the electronics industry, are generally comprised of metal, typically steel or aluminum.  
           [0006]    For examples of prior art panels and their methods of attachment to rack units see Peroni in U.S. Pat. No. 5,971,507 and Odell in U.S. Pat. No. 5,312,005. The devices disclosed do not illustrate a novel means for attaching panels to a rack unit. The references employ standard elongated orifices positioned near the ends of the panel to accept threaded fasteners. In U.S. Pat. No. 5,992,808 Morrow teaches the use of a “key” for attaching electronic components and panels to rack units. The key has a geometry so as to be insertable through openings on the periphery of a panel, and subsequently through corresponding openings in a rack unit. On rotating the key through 90 degrees the key locks in position, thus securing the panel in place. This method for attaching panels to rack units offers the advantage of not requiring special tools, however, it also requires that the rack unit be modified to lock the keys in the rotated position. A further shortcoming is inherent in the shear number of individual keys required to attach a single panel to a rack unit, such loose parts are both cumbersome and at risk for loss.  
           [0007]    References in the prior art do not discuss a means for directly incorporating fasteners with blank panels. The references also generally require special tools to operate the fasteners which they employ. Further, the prior art does not overcome the limitation of an individual blank panel not being adaptable to accommodate various height requirements.  
           [0008]    What is needed is a blank panel that is attachable to racking units in a secure manner, which employs fasteners that do not require the use of special tools or equipment. The fasteners should be easy to replace and accommodate various rack configurations. The blank panel needs to be functional, light weight, modular and versatile. The blank panel should conform to recognized standards for racks, panels, and associated equipment. It would also be useful if the blank panel could be modified to accommodate varied height requirements.  
         OBJECTS AND ADVANTAGES  
         [0009]    Accordingly, it is a primary object of the present invention to provide a blank panel that can be securely attached to electronic component rack units.  
           [0010]    It is a further object of the invention to provide a blank panel for rack units that is attachable without the use of special tools.  
           [0011]    It is a further object of the invention to provide a blank panel for electronic component rack units comprising at least one face plate with means for slidably receiving fasteners.  
           [0012]    It is a further object of the invention to provide a blank panel for electronic component rack units, wherein the blank panel comprises a plurality of face plates capable of covering multiple adjacent openings.  
           [0013]    It is a further object of the invention to provide a blank panel for electronic component rack units incorporating a plurality of face plates, wherein individual face plates of the blank panel are modular and can be separated to configure the blank panel to varied height requirements.  
         SUMMARY  
         [0014]    The objects and advantages of the invention are accomplished by a blank panel that is configured to be attachable to a rack unit. The blank panel generally comprises at least one face plate having a substantially rectangular front plate surface, a back plate surface, top plate surface, bottom plate surface and two side plate surfaces. The face plate has a height preferably corresponding but not limited to multiples of 1.75 inches. The face plate is capable of slidably receiving fasteners for being further attached to an electronic component rack unit.  
           [0015]    Fasteners are incorporated to mate with the face plate of the blank panel and be attachable to electronic component rack units. The fasteners are configured to securely attach to electronic component rack units with alternate configurations substantially without use of assembly tools.  
           [0016]    In a preferred embodiment of the invention, the blank panel is comprised of a plurality of face plates held together along their length with break-off grooves that provide for a manual separation of individual face plates and at the same time warrant sufficient structural strength for the blank panel.  
           [0017]    The components of the blank panel are preferably monolithically fabricated of a polymer for light weight and durability. Optional glass fiber or the like may be added to the polymer to increase the blank panel&#39;s stiffness and/or to modulate a break-off characteristic of the break-off grooves.  
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0018]    [0018]FIG. 1 shows a perspective front view on a plank panel of combined face plates and fasteners.  
         [0019]    [0019]FIG. 2A is a perspective back view of the plank panel and fasteners of FIG. 1.  
         [0020]    [0020]FIG. 2B is an enlarged detail view indicated in FIG. 2A by numeral  121 .  
         [0021]    [0021]FIG. 3 is an enlarged perspective view of the fastener of FIGS. 1, 2A.  
         [0022]    [0022]FIG. 4 is a side view of a single face plate and the fasteners of FIG. 1.  
         [0023]    [0023]FIG. 5A shows two face plates in a first bent position during face plate separation.  
         [0024]    [0024]FIG. 5B is an enlarged detail view indicated in FIG. 5A by numeral  121 .  
         [0025]    [0025]FIG. 6A shows the two face plates of FIG. 5A in a second bent position during face plate separation.  
         [0026]    [0026]FIG. 6B is an enlarged detail view indicated in FIG. 6A by numeral  121 .  
         [0027]    [0027]FIG. 7 shows the two face plates of FIG. 5A immediately after face plate separation. 
     
    
     DETAILED DESCRIPTION  
       [0028]    Referring to FIGS. 1 and 2, a blank panel  1  includes preferably three face plates  10  separable combined along break-off grooves  121  extending between two opposing side surfaces  16 . The face plates  10  have contact faces  13  on opposing ends and adjacent the side surfaces  16 . The contact faces  13  are separated by reinforcement ribs  55 . The contact faces  13  are substantially planar along a first width  131 . The reinforcement ribs  55  extend along the second width  551 .  
         [0029]    From preferably each of the side surfaces  16  extend inward along the contact faces  13  two finite channels  25  featuring overhead extensions  30 . The channels  25  are defined in combination with the overhead extensions  30  to exchangably and slidably hold correspondingly shaped mating structures  61 .  
         [0030]    The contact faces  13  may additionally feature positioning indicators  52  for indicating a predetermined position for the fasteners  60  with their mating structures  61 . As an advantageous result, fasteners  60  may be brought into appropriate position along channels  25  prior to attachment of the face plates  10  and/or blank panel  1 .  
         [0031]    Referring to FIG. 2B, the break-off groove  121  includes a thin film bridge  125  structurally exclusive connecting two adjacent face plates  10 . Positioned in a groove angle GA and oppositely of the thin film bridge  125  are levering faces  126  for inducing a tension force onto the thin film bridge  125  at and in excess of a break-off bending angle B 2  (see FIG. 6B) imposed on two adjacent face plates  10  preferably during manual face plate separation.  
         [0032]    The mating structure  61  is part of the fastener  60  further illustrated in FIGS. 3 and 4. The fastener  60  has at least two laterally resilient protrusions  65  extending substantially symmetrically with respect to an attachment axis  69 . The attachment axis  69  is substantially perpendicular with respect to a contact face  13  while the mating structure  61  is held in a corresponding channel  25 .  
         [0033]    The protrusions  65  preferably feature straddle lags  651  that extend away from the mating structure  61  in an straddle angle  652  such that the resilient protrusions  65  induce a pulling force via the straddle legs  651 , the column  62  and the mating structure  61  on the associated face plate  10 , while the resilient protrusions  65  are inserted in an orifice hole  4  of the mounting bar  3 . As a favorable result, the blank panel  1  and/or face plate  10  is forced with the associated contact face  13  against the mounting bar  3 , while the fastener additionally holds the blank panel  1  and/or face plate  10  in position. In FIG. 4, mounting bar  3  and orifice hole  4  are indicated in dotted lines.  
         [0034]    Front surfaces  12  of the face plates  10  may be fabricated with a slight curvature in direction across the main protrusion direction of the blank panel  1 , which provides for a smooth thickness reduction of the main plate bodies towards the intersections. In that manner, the main plate bodies may be fabricated with sufficient strength along the main protrusion direction to sufficiently oppose torsion deformation resulting during the preferably manual face plate separation. At the same time, the height of the intersections  121  may be kept to a minimum, providing a maximum leverage effect and consequently maximum tension load from a given torque preferably manually induced at some point along the protrusion direction of the blank panel  1 .  
         [0035]    The lateral resilient protrusions  65  may further include parallel legs  652  and converging legs  653  terminating in a single closed tip. In that way, the protrusions  65  may provide a certain self centering action when approached to the predetermined orifice hole  4 . The parallel legs  652  may assist in adjusting the protrusions  65  deformation behavior and reduce peak stresses by providing sufficient deformation length of the protrusions  65  as may be well appreciated by anyone skilled in the art. Preferably two but also three or more lateral resilient protrusions  65  may be concentrically arrayed around the attachment axis  69 .  
         [0036]    The intersection  121  is configured to provide sufficient stiffness to the blank panel  1  and at the same time warrant limited opposition to a manual face plate  10  separation, which may be performed in a two step process. During a first bent indicated in FIG. 5A, two adjacent face plates  10  are bent in an angle B 1  with the front faces  12  towards each other. During the initial first bend, the thin film bridge  125  is excessively deformed after overcoming its natural stiffness. During a consecutive second bend indicated in FIG. 6A, the two involved face plates  10  are bent in an angle B 2  in opposite direction with the reinforcement ribs  55  towards each other. At the moment when the second bend angle B 2  approximately exceeds the groove angle GA, the levering faces  126  contact and become forced against each other as the second bend angle B 2  is further increased. This results in a tensile load on the previously weakened thin film bridge  125 , which eventually spontaneously rips, completely separating the two adjacent face plates  10  as illustrated in FIG. 7.  
         [0037]    The blank panel  1  is preferably monolithically fabricated by injection molding. A preferred polymer material is a well known ABS with optional contents of glass or other stiffening fibers. The fiber contents may be adjusted in conjunction with the dimensions of thin film bridge  125  and groove angle GA to warrant instantaneous and complete separation as may be well appreciated by anyone skilled in the art.  
         [0038]    Accordingly, the scope of the invention should be determined by the following claims and their legal equivalents.
A plank panel for covering fronts of electronic equipment racks consists of preferably three face plates separable via a break-off groove such that the plank panel may be easily reduced to a lesser height. The face plates provide slots for fasteners that slide in from the side and are adjustable to slight dimensional discrepancies and various configurations of the mounting holes of various rack systems.