Abstract:
A shelf having two telescoping plates secured by a toothed crank is provided for locker users. The plates have a generally rectangular shape with perimeter edges reinforced by lips and pads to engage the locker walls. Friction between the pads and the walls holds the present invention at a desired elevation. This shelf has a toothed rack upon a first plate and a crank with teeth upon the second plate. The teeth upon the crank engage the rack and turning of the crank secures the second plate relative to the first plate longitudinally at a desired width for fitting against the inner walls of a locker.

Description:
CROSS REFERENCE TO REALTED APPLICATION 
   This nonprovisional patent application claims priority to the provisional patent application having Ser. No. 60/655,874, which was filed on Feb. 24, 2005. 

   BACKGROUND OF THE INVENTION 
   This invention relates generally to shelving and more specifically to a longitudinally extendable shelf. 
   People often need to store items when moving outside to inside of a building or between work areas within a building. Students store coats and books in lockers at school while workers store outerwear and tools in lockers at a workplace. Further athletes store clothing and other items in lockers at athletic facilities of all kinds. 
   The typical locker has, behind the door, one shelf at nearly eye level. Students and athletes can quickly fill a single shelf. Other lockers, often in workplaces, lack shelving. Workers merely stack items within those lockers. The clever students and workers provide and construct additional shelving for their lockers. Such shelving can be plywood plates upon pins in the walls of a locker, milk crates, or other paneling simply supported. Existing shelving typically has a fixed size, usually suitable for one locker alone. Further students and workers provide such shelving at their own expense and labor. 
   DESCRIPTION OF THE PRIOR ART 
   Various types of shelves and components have been available for the storage industry. The prior art shelves fit within lockers and attach to the walls of a locker in a variety of ways. Adjustable gates provide a mechanism to extend portions of the gate lengthwise. Some mechanisms use ratcheting teeth or screws to secure or to extend a gate or shelf. 
   For example, the patent to Bluem, et al., and assigned to North States Industries, Inc., U.S. Pat. No. 4,607,455 first shows handle gear related to the present invention. This expired patent covers an adjustable gate for doorways. 
   The patent to Larson et al., also assigned to North States Industries, Inc., U.S. Pat. No. 4,677,791 relates to the adjustable gate for a doorway, but more specifically pertains to the mounting socket. 
   The design patent to McNamara et al., assigned to Minnesota American, Inc., U.S. Pat. No. Des. 355,551, illustrates a legless locker shelf assembly. Though this particular locker shelf expands, the appearance and structure of this patented device is just totally dissimilar from the appearance and function of the present invention. 
   Earlier, the patent to Peterson, assigned to Sioux Technology Inc., U.S. Pat. No. 4,500,146 shows the use of shelving, which is expandable, and which can be forced against the interior walls of a locker, to furnish supplemental storage. 
   Then the patent to McNamara et al., assigned to Minnesota American, Inc., U.S. Pat. No. 5,421,646, describes another legless locker shelf assembly. In this assembly, the side walls of its first and second shelf members have releasable cooperating holding means that retain the first and second shelf members in expanded positions. These holding means, associated with the side walls, are the operating ratchet teeth that hold the shelves separated when they are expanded. While the ratchet teeth may be releasable, they are intended to retain the first and second shelf members in an expanded position, once expanded. The present invention does not show or disclose any type of that structure. The shelves of the present invention are free to slide into expansion or contraction, all the time, and are not held in expanded position, by anything operatively connected with its side walls. 
   And, McNamara &#39;646 defines the releasable cooperating holding means as the first and second sets of ratchet teeth, operatively cooperating with the side walls. This is not the structure of the present invention. The present invention lacks the side walls that have these engaging ratchet teeth. McNamara &#39;646 goes on to define a cam actuator means having a spiral-shaped outer portion that engages with at least one of the cam follower teeth that are attached to the top of the shelf.  FIGS. 8 and 9 , of the &#39;646 patent, once again, show that the cam follower teeth are forced into expansion by the outer end portion of the spiral cam actuator. 
   And, the patent to Santucci, No. U.S. Pat. No. 5,137,160 describes a self supporting locker shelf similar to the present invention. The Santucci &#39;160 patent defines a self-supporting locker shelf comprised of first and second planar and rectangular shelf members, attached to each other for pivotal movement. The present invention has linear or longitudinal movement for its shelves, relative to each other, and not pivotal movement. 
   SUMMARY OF THE INVENTION 
   This invention generally defines a shelf having two telescoping plates controlled by a toothed crank and a rack. The plates have a generally rectangular shape with perimeter edges reinforced by downturned lips. The outer edges of the plates have pads to abut the interior walls of a locker. Friction between the pads and the walls holds the present invention, under a load, at a desired elevation within the locker. 
   More specifically, this locker shelf has a toothed rack upon a first plate and a crank with teeth upon the second plate. The teeth upon the crank engage the rack and turning of the crank secures the second plate relative to the first plate longitudinally. Using the crank, the first plate and the second plate attain an overall width that adjusts to meet the width presented by the interior of a locker. 
   Further this locker shelf has the rack and crank generally located in the center of the invention and upon the lower surface of the respective plates. The plates have an open grid pattern flanking the rack and crank to allow for ventilation and display of the interior of the locker. 
   This therefore is the principal object of the present invention to secure two aligned plates extending across the interior width of various lockers. 
   Another object of this invention is to provide a shelf that extends without use of tools. 
   Still another object of this invention is to provide a shelf that does not permanently attach to a locker, and can be readjusted to other positions. 
   Still another object is to provide such a shelf that can be easily and efficiently manufactured and marketed to the consuming public. 
   These and other objects may become more apparent to those skilled in the art upon review of the summary of the invention as provided herein, and upon. undertaking a study of the description of the preferred embodiment in view of the drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In referring to the drawings,  FIG. 1  shows an isometric top view of the locker shelf; 
       FIG. 2  shows an isometric bottom view of the present invention; 
       FIG. 3  provides an isometric top view of the second plate; 
       FIG. 4  describes an isometric bottom view of the second plate, 
       FIG. 5  illustrates the crank of the present invention; 
       FIG. 6  shows the two plates of the shelf locked together. 
   

   Corresponding reference numerals will be used throughout the several figures of the drawings. 
   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   In referring to  FIG. 1  of the drawings, the concept of this invention or device  1  is readily disclosed. The device  1  includes, as depicted therein, a first plate  2  generally rectangular in shape and a second plate  4  that extends from the first plate  2 . The second plate  4  has a slightly narrower width than the first plate  2 . Each plate has a turned down edge or lip  3  upon three or more perimeter sides. The first plate  2  has two longitudinal edges  2   a  and one lateral edge  2   b  perpendicular to the longitudinal edges  2   a . The second plate  4  also has two mutually parallel spaced apart longitudinal edges  4   a  but two mutually parallel spaced apart lateral edges  4   b  perpendicular to the longitudinal edges  4   a . The lips  3  reinforce the perimeter of the shelf  1  and increase rigidity of the shelf  1  when under load. Upon the outer lips  3  of each plate, two or more pads  17  extend further outward to grasp the wall of a locker. The pads  17  have a generally round shape and secure into slots within the lip  3 . The slots open downward so the shelf  1  remains on the pads  17  when upright and under a load. In the preferred embodiment, each plate has an open pattern of holes  15  flanking the longitudinal axis. The holes  15  provide ventilation and allow the user to see through the shelf  1  if needed. Centered between the holes  15 , each plate has a solid longitudinal strip or spine  16  that conceals a means to secure or securing mechanism  6  of the shelf  1 . Flanking the spine  16 , the first plate  2  has two spaced apart and mutually parallel tracks  7  visible upon the top surface. The tracks  7  have a lengthwise slot  8  and run in the longitudinal direction of the shelf  1 . 
   The securing mechanism appears in  FIG. 2  beneath the spine  16  of both plates. Beneath the first plate  2 , the securing mechanism has a toothed rack  12 . The rack  12  extends longitudinally. The teeth  12   a  are adjacent to a pattern of holes  15  upon one side of the spine  16 . Corresponding to the teeth  12   a , a crank  13  beneath the second plate  4  secures the second plate  4  relative to the first plate  2  when turned. The crank  13  has a handle  13   d  offset from a head  13   a  later shown in  FIG. 5 . Opposite from the head  13   a , the handle  13   d  approaches a pair of stops  14 . The stops  14  are mutually spaced apart for a snug fit of the handle  13   d . When engaged, the stops  14  prevent the handle  13   d  from rotating when the shelf  1  is secured. 
   Also beneath the first plate  2 , a gusset  7   a  supports each track  7  upon which the second plate  4  slides. The tracks  7  serve as one component of a means for telescoping  5  the second plate  4  longitudinally from the first plate  2 . Upon the other end of each track  7 , the first plate  2  has a glide  8 . The glides  8  are located at the lower edge of the lips  3  on the edges  2   a  also parallel to the longitudinal direction of the shelf  1 . The glides  8  support the lips  3  on the longitudinal edges  4   a  of the second plate  4  and form a load bearing connection of the second plate  4  to the first plate  2  at any width of the shelf. Moving to the second plate  4  and opposite the pads  17 , gussets  7   a  support the keys  10  extending above the second plate  4  collinear with the tracks  7  of the first plate  2 . 
   The keys  10  of the second plate  4  appear more clearly in  FIG. 3 . Upon the top surface of the second plate  4 , two depressed parallel grooves  11  run. Opposite the pads  17 , each groove  11  has a key  10 . The key  10  has a generally T shaped cross section that engages the groove  11  upon the first plate  2 . The keys  10  and grooves  11  cooperate to extend the second plate  4  longitudinally from the first plate  2  while maintaining a structural connection between the plates. Generally centered between the keys  10 , the head  13   a  is located upon the spine  16  opposite the pads  17 . The head  13   a  has a generally round flat shape with two or more teeth  13   b  radially disposed upon the circumference of the head  13   a . In the preferred embodiment, the head  13   a  has three teeth  13   b  regularly spaced so the teeth  13   b  permit partial rotation of the handle  13   d  when engaging the rack  12 . The rotation of the crank  13  induces extension of the second plate  4  slightly from the first plate  2  for a friction fit. 
   Turning beneath the second plate  4 ,  FIG. 4  shows the handle  13   d  of the crank  13 . The handle  13   d  has a tapered elongated shape with a grip  13   f  upon one end. Opposite the grip  13   f , a hole admits the stem  13   c  of the head  13   a . With a lip adjacent to the stem  13   c , the crank  13  can rotate within 180° when moving the second plate  4  relative to the first plate  2 . Proximate to the pads  17  and opposite of the keys  10 , gussets  11   a  support the outer corners of the second plate  4 . 
   The crank  13  appears alone in  FIG. 5 . As before, the head  13   a  has a round flat shape with two or more teeth  13   b  extending radially. Via a stem  13   c  through the second plate  4 , the head  13   a  attaches to the handle  13   d . Proximate to the head  13   a , the handle  13   d  has a rounded end where the head  13   a  and teeth  13   b  fit within the shape of the handle  13   d . Away from the head  13   a , the handle  13   d  tapers in width as an elongate form. As shown in  FIG. 4 , the handle  13   d  has reinforcement perpendicular and beneath the handle  13   d , opposite of the head  13   a . In the preferred embodiment, the reinforcement is a triangular shaped rib  13   e  where the point of the triangle approaches the stem  13   c . At the opposite end of the rib  13   e , a grip  13   f  attaches to the rib  13   e  beneath the handle  13   d  and the second plate  4 . In the preferred embodiment, the grip  13   f  has a rectangular shape within the width of the handle  13   d.    
   In use, a user places the lip  3  on a lateral edge  4   b  of the second plate  4  opposite the pads  17  into the first plate  2  where no lip  3  is present. The lips  3  of the second plate  4  pass upon the glides  8  and slide beneath the surface of the first plate  2 . The second plate  4  within the first plate  2  forms the shelf  1 . The user then inserts the shelf  1  at an angle into a locker. The user then levels the shelf  1 , extends the first plate  2  and the second plate  4  outwards against the locker walls, and then reaches beneath the shelf  1  to grasp the crank  13 . Turning the crank  13 , the user extends the second plate  4  relative to the first plate  2  then induces more friction between the pads  17  and the locker walls when the teeth  13   b  engage the rack  12  as the user turns the crank  13  for a tight fit of the  1  shelf. When the crank  13  reaches the longitudinal axis of the shelf  1 , the user places the rib  13   e  within the stops  14  to fix the crank  13  in place and the width of the shelf  1 . 
   Variations or modifications to the subject matter of this invention may occur to those skilled in the art upon reviewing the summary of the invention as defined herein, and upon undertaking a study of the description of its preferred embodiment. Such variations, if within the spirit of this development, are intended to be encompassed within the scope of the invention as shown and described herein. The specific depiction of the invention, as described, and as shown in the drawings, is set forth for illustrative purposes only. 
   From the aforementioned description, an adjustable shelf has been described. The adjustable shelf is uniquely capable of extending one plate relative to another plate to adjust the width of a shelf to meet various widths. The adjustable shelf and its various components may be manufactured from many materials including but not limited to polymers, high density polyethylene HDPE, polypropylene PP, polyethylene terephalate ethylene PETE, polyvinyl chloride PVC, polystyrene PS, nylon, ferrous and non-ferrous metals, their alloys, and composites.