Abstract:
A flat file for storing drawings, providing an easy way to pull a drawing from the middle of a stack of drawings without disrupting the previous order of the stack. A movable board mechanism allows one to lift the drawings stacked on top of a selected drawing and hold them while the selected drawing is retrieved. Later the drawing can be replaced under the board mechanism and the stack returned to its original order.

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 07/359,977, filed on June 1, 1989, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     In forty years of experience in the technical community, this inventor has seen a revolution in the drafting medium of choice for inking from tracing cloth to mylar. While mylar has great linear stability and virtual indestructibility, it nevertheless has inherent problems which have never been addressed in the design of flat files, to wit: being a dense, heavy material, with a very low surface friction, it is extremely mobile in the file drawer, and this weight and mobility make refiling drawings in the proper order very daunting and unrewarding, since it is an awkward process, and any amount of care is undone the very next time a drawing is removed from the stack. As one drawing is removed from the middle of the stack, others tend to stick to it and the whole stack has to be realigned before a new drawing can be located. A new approach to the drawer principle, which is basically still a sound idea, is needed to circumvent these problems. 
     SUMMARY OF THE INVENTION 
     Briefly described, the present invention is a flat file comprising a cabinet, tailored to closely fit one specific size drawing. A stack of drawings will ordinarily be stored in the lower portion of the cabinet. The file includes a board approximately half way up in the cavity, which can be interposed at a point in the stack where a desired drawing is located. This is done by manually raising the overlying drawings to facilitate entry of the board. The board is inserted under these drawings and the desired drawing, beneath the board, is then easily retrieved. After replacing it under the board, withdrawing the board allows the stack to recombine by gravity to its original condition. 
     The basic embodiment for an individual file is a box with a rigid board mounted on full-extension drawer slides. Unfortunately, as the board size increases, the reach across the board when it is withdrawn from the box in order to access the file becomes increasingly onerous. One preferred embodiment of the present invention addresses this problem by adding a &#34;lag panel&#34; which, through a mechanical linkage to the box itself, retracts into a cavity inside the board as the board is pulled out. Since this cavity must degrade the beam strength of the board somewhat, the effect is minimized in preferred embodiments by making the lag panel as wide as possible, so that its beam strength, rather than that of the board, can be relied on for rigidity. 
     It is therefore an object of the present invention to provide a flat file which functions to lift part of a stack of drawings in the file and hold them suspended above the drawings below while a drawing is either removed from or inserted on the top of the underlying stack of drawings. 
     Another object of the present invention is to also provide a flat file which allows easy access to any drawing in the file without disrupting the order of the drawings. 
     Yet another object of the present invention is to provide a flat file with a sliding board assembly having a retractable panel therein for reducing the effective width of the board assembly. 
     Other objects, features, and advantages of the present invention will become apparent upon reading and understanding of this specification, taken in conjunction with the accompanying drawings. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a pictorial view for a flat file in accord with the present invention, showing one embodiment thereof. 
     FIG. 2 is a frontal elevation of the file of FIG. 1, with the gate below the board shown only in part. 
     FIG. 3 is a detail of a center hinge boss for the gate of the flat file of FIG. 1, in accordance with one embodiment. 
     FIGS. 4 and 5 are cross-sectional details of the file of FIG. 1, demonstrating technique in removal and return of a drawing. 
     FIG. 6 is a pictorial view of one embodiment of the present invention with the board inside the file. 
     FIG. 7 is a pictorial view of one embodiment of the present invention with the board partially withdrawn and the lag panel fully extended. 
     FIG. 8 is a pictorial view of one embodiment of the present invention with the board fully withdrawn and the lag panel fully retracted. 
    
    
     DETAILED DESCRIPTION 
     Referring now in greater detail to the drawings, in which like numerals represent like components throughout the several views, a preferred embodiment of the file of the present invention is seen in FIG. 1 and FIG. 2 as including a box or cabinet 1, open at the front, and having fixed panels at the top 40, bottom 41, left side 42a, right side 42b, and back side 44. Interior side panels 6a and 6b are attached to the top 40, bottom 41, and back 44, parallel to side panels 42a and 42b respectively. 
     The cabinet 1 is open on the front, as shown in the illustrated embodiment, to allow a board 10 to be alternately inserted or withdrawn from the cabinet 1. A cutout area 8 at the front of the top 40 facilitates access to the file interior. Keepers 5a, 5b are attached to the front of sides 42a, 42b above the board 10, and serve to decrease the size of the opening at the front of the cabinet 1. A slight thinning 16a, 16b at the left and right edges of the board 10 allow the lower edges 33a, 33b of the keepers 5a, 5b to barely break below the plane of the board 10. Due to this thinning 16a, 16b of the board edges, the keepers 5a, 5b serve to hold drawings that are on top of the board 10 inside the cabinet as the board 10 is removed from the cabinet. 
     Lower cavity panels 2a, 2b below the plane of the board 10, and upper cavity panels 4a, 4b above the plane of the board 10, extend front to rear of the cabinet and define the file cavity width. Cantilevered from the front end of each upper cavity panel 4a, 4b is a magnet 3a, 3b. 
     The board 10 is a built-up structure and is provided with an internal lag panel 20. An unbroken recess 14 accommodates the internal lag panel 20 in the interior of the board 10. The lag panel is freely movable from front to back of the board within this space and is guided by rails 17a, 17b extending from the front 24 to the rear 18 of the lag panel recess 14. At each side of the rear edge 15 of the board 10 and cantilevered out as shown in FIG. 2 are magnets 11a, 11b so located as to engage the matching aforementioned magnets 3a, 3b when board 10 is fully withdrawn from the cabinet (Ref. 34, FIG. 8). The rear edge 15 of board 10 is tapered (see FIG. 5). 
     On each rear side of board 10 is a stepped-in opening 13a, 13b and the board width is narrower from the openings 13a, 13b to the rear edge 15 of the board 10. Full extension drawer slides 30a, 30b mount on the fixed side to internal bulkhead 6a, 6b and on the sliding side to a bracket 31a, 31b which in turn mount the board 10. 
     Lag panel 20, as denoted by the cross-hatch in FIG. 2, has built-in saddles 25a, 25b, which guide it on rails 17a, 17b of the board. An L-shaped link 21a, 21b is rigidly attached to each rear corner of the lag panel and these links extend out through the stepped-in side openings 13a, 13b in the board (see FIG. 1). The interior side panels 6a, 6b each have an elongated hole or channel 7a, 7b for most of their length, and a flared end section 22a, 22b at the free end of each link 21a, 21b projects through the elongated opening 7a, 7b in each respective interior side panel 6a, 6b. A limber spring 23a, 23b (capable of doubling its extension) attaches each link 21a, 21b to the inner surface of the front board facia 24a, 24b. 
     Gate 26 (shown ajar in FIG. 1) is shown closed in FIG. 5. It is represented by the fine crosshatch symbol in FIG. 2 showing a preferred embodiment. A drop 35 in its upper edge, adjacent to the &#34;Pull Here&#34; applique 19, allows for an easy thumb hold when gripping the board 10. A center hinge boss 37 (FIG. 3) supports a hinge pin 38 for mounting the gate 26. An oversized cutout 36 at the lower edge of the gate 26 facilitates assembly on the center hinge 37 while hinge pin 9 provides end support. A light-weight spring 27 (one side only) is adequate to provide closure, with its upper extremity 28 embedded in the end surface of the gate 26, and its lower end 29 bearing against the bottom 41 of the cabinet. 
     In the illustrated embodiment, a rectangular cutout 12, through one front side of the board 10, provides exposure of lag panel 20 (see FIGS. 6-7). As the board 10 is withdrawn from the cabinet a distance &#34;a&#34; (see FIG. 7), the lag panel 20 stays at the front of the board 10. Then, as the board advances between distance &#34;a&#34; and distance &#34;b&#34;, (see FIG. 8) the lag panel 20 stays put and the cutout 12 allows closer access to the front of the cabinet 1. The lag panel does not advance with the board as it moves on from distance &#34;a&#34; to distance &#34;b&#34;, since the link interface 22a, 22b reaches the end of channel 7a, 7b and restrains it from farther advance. Pulling the board 10 out any farther builds potential energy in the springs 23a, 23b until at the limit of its travel 34 (FIGS. 1, 8), (corresponding with the limit of travel of the drawer slides 30a, 30b) magnets 3a, 3b and 11a, 11b engage, holding the board in the extended position until an inboard impulse breaks the magnetic bond. 
     The amount of lag shown in FIG. 1 was established by consideration of what would be an acceptable approach distance for the average user. By way of example only, the approach distance is taken arbitrarily to be 18 inches. This results in a lag for a 24×36 inch unit of 6 inches. For the larger unit (e.g. 30×42) the lag panel 20 and its recess 14 would take up proportionately more of the board interior (and make the board cut-out 12 deeper as well). Conversely, for a smaller size (17×22) there would be no lag panel needed. Since this would also eliminate the springs 23a, 23b, such a unit without a lag panel could have weaker magnets, since their function is thence much reduced. 
     USE: To retrieve a drawing from the file, the user first pulls the board out until the magnetic latch engages. Then, positioning himself at the operator station defined by the board cut-out 12 (FIG. 1), he now has both hands free to reach over and thumb through the file to locate the desired drawing. Lifting the leading edge of the overlying portion of the stack (i.e. that portion overlying the desired drawing) throughout its length well clear of the board&#39;s rear edge 15, he applies a sufficient forward pressure to the board 10 with his midriff to break the magnetic bond, allowing the energy released in the springs to propel the board inward under the drawings so elevated. He can now free his left hand to push the board the rest of the way in, while still keeping his grip with the right hand. The inward movement of the board 10 serves to further lift the overlying portion of the stack; and the board supports the overlying portion at a distance above the desired drawing. By the technique in FIG. 4, he now retrieves his desired drawing from its exposed position under the board. When ready to return it to the file, it is slipped into the aperture between the gate and the board (FIG. 5) with enough thrust to propel it completely into the file cavity. Finally, the file is restored to its original condition by pulling the board out, in which process the keepers 5a, 5b restrain the overlying drawings from moving forward with the board, so the file recombines by gravity. The board can be pushed back in, for storage, above the recombined stack. 
     Whereas the present invention has been described in detail with specific reference to particular embodiments thereof, it will be understood that variations and modifications can be affected within the spirit and scope of the present invention as hereinbefore described and as defined in the appended claims.