Field of the Invention
The present invention relates to the field of optical fiber interconnection and more particularly to splice trays therefor.
Background of the Invention
In multiple fiber interconnection arrangements, a plurality of pairs of associated optical fibers are to be interconnected and such interconnections must thereafter be held securely and carefully, usually in an organizer tray or cassette within a larger enclosure or cabinet, and usually in an array of such trays or cassettes. Splice trays must also hold generous portions of the fibers adjacent the interconnections, or splices, to permit splice repair without requiring cable replacement. Preferably the trays are flat and of low height to be conveniently stacked in array thereof, and further include a cover that is preferably transparent to enable visual inspection of the splice interconnections. Such a cover must be easily secured to the tray in a manner permitting it to be easily removed from the tray for repair or servicing. In one manner of cover securement, the cover is of resilient material and includes side walls that are angled toward each other and are latchable about the side walls of the tray proper, being slightly deflectable outwardly by bearing engagement with the tray side walls during cover assembly or removal.
One such splice tray is disclosed in U.S. patent application Ser. No. 08/453,303 filed May 30, 1995, pending, and assigned to the assignee hereof. The disclosed splice tray provides strain relief holders at each end having an array of slots into which portions of the optical fiber cables are inserted to be held securely but without substantial clamping of the fiber cables. Additionally, the optical interconnections of associated pairs of optical fibers of the cables are held in a generally centrally located slotted splice holder, again without substantial clamping of the fragile fibers. The disclosed splice tray is adapted for utilization with either single-fiber or multiple-fiber cylindrical cable or flat wide multiple-fiber ribbon cable.
It is desired to provide a tray cover that is planar, having no features requiring a forming step, and is securable to a tray without separate fasteners in a manner permitting easy removal when desired.
Summary of the Invention
The tray member provides a tab along at least one side wall located adjacent an end of the tray, and preferably tabs on both side walls near each end, first protruding upwardly a slight distance above the upper or free side wall edge and including an inwardly directed retaining section at the tab end. Cooperating retaining sections of the cover underlie the tray tab retaining sections, preventing the cover from being lifted off. The tray cover includes along one or each side edge near but spaced from an end, a deflectable portion such as a tab. Extending inwardly from one side of each such deflectable portion adjacent an associated tray tab, and preferably both sides of a cover tab, is a slot, allowing the tab to define a cantilever beam manually deflectable upwardly a limited extent, with an end thereof preferably protruding slightly outwardly of the side of the tray to enable manual engagement.
The cover is adapted to be slid onto and off the tray from an end of the tray, or preferably, slid a fixed distance along the tray and thereafter lifted. During cover assembly and removal, the deflectable portion or cover tab is deflectable to ride over the tray tab while the side edge portions of the cover slide atop the tray side wall free edges and beneath the inwardly directed tray tab end. During assembly, the tray tab free end secures the planar cover adjacent the tray side wall free edges, and the cover tab resiles to rest within the plane of the cover after passing inwardly beyond the tray tab, a side edge of the cover tab adjacent the inner side edge of the tray tab defining cooperating stop surfaces maintaining the cover on the tray fixed against sliding. During removal, the cover tab is easily engageable manually to be deflected upwardly to again ride over the tray tab as the cover is slid off the tray end.
It is an objective of the present invention to provide a tray cover that is easily securable to a splice tray without separate fasteners, and in a manner permitting removal.
It is another objective to provide a tray cover that is planar and is fabricated simply such as by stamping to define cover features cooperable with the tray that are within the plane of the cover, thereby obviating any forming steps.
It is still another objective to provide the tray cover with at least one upwardly deflectable portion, such as a cover tab, that when undeflected cooperates with a tray tab to prevent sliding, and when deflected can ride over the tray tab to permit sliding of the cover relative to the tray.
It is yet another objective to provide the tray cover with features that permit lifting the cover off the tray after limited sliding.
An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings.
Brief Description of the Drawings
FIG. 1 is a plan view of a splice tray of the prior art;
FIG. 2 is an isometric view of the assembly of the splice tray and cover of the present invention;
FIGS. 3 and 4 are plan and end views of the splice tray assembly of FIG. 2;
FIGS. 5, 6 and 7 are plan, side and end views of the splice tray of FIGS. 2 to 4; and
FIG. 8 is a plan view of the tray cover of FIGS. 2 to 4.
Detailed Description of the Preferred Embodiment
In FIG. 1 a prior art splice tray 10 is shown having cable holders 12 adjacent each end and a splice holder 14 disposed intermediate the ends, with representative optical fiber cables shown contained in the splice tray. Such a splice tray is disclosed in U.S. patent application Ser. No. 08/453,303 filed May 30, 1995.
FIGS. 2 to 4 illustrate the present invention. Splice tray assembly 20 includes a tray member 22 and a cover member 24 affixed thereto; assembly 20 is simplified in that no optical cables are shown. In FIGS. 3 and 4 cable holders 26 similar to cable holders 12 of FIG. 1 are shown affixed at each end 28,30 of tray member 22 where openings between the tray and the cover are defined providing entrances for the optical fiber cables. Assembly 20 is seen to be flat and have a low profile facilitating stacking in a splice tray array.
In FIGS. 5 to 7, tray member 22 includes a bottom wall 32, with side walls 34,36 coextending therefrom. Flanges 38 extend inwardly from top edges of side walls 34,36 parallel to bottom wall 32 along the central portion of the tray, that will serve to contain portions of loops of the optical fibers during assembly of the fiber splice interconnections prior to and during placement of cover 24 thereonto. Adjacent each tray end 28,30 and along both side walls 34,36 are defined tray tabs 40 protruding slightly beyond top edges of side walls 34,36 and having side edges 42. Free ends of tray tabs 40 are bent to extend inwardly to define retainer sections 44 positioned higher than the upper surfaces of flanges 38, as seen best in FIG. 6, spaced thereabove a distance slightly greater than the thickness of cover member 24. Cutouts (FIG. 5) are provided in bottom wall 32 at the base of each tray tab 40 sufficient to receive thereinto the elevated retainer sections of a similar tray stacked thereunder. Several pairs of holes 48 are shown provided at each end 28,30 along each side wall 34,36 enabling fastening of cable ties (not shown) if desired to be utilized for securing larger fiber optic cables (not shown) extending through the end openings beside cable holders 26 (FIG. 3) Also seen are rod-receiving holes 50,52 through bottom wall 32 enabling stacks of tray assemblies to be secured onto stacking rods (not shown).
Cover member 24 is seen in FIG. 8, and is planar as seen best in FIGS. 2 and 4. End portions 56 are associated with tray ends 28,30 to enclose the cable entrances of the assembly above the cable holders. Side edge portions 58,60 will overlie flanges 38 of tray member 22. Proximate end portions 56 are cooperating retainer sections 62 that will underlie retainer sections 44 of tray tabs 40 while side edge portions 58,60 overlie flanges 38, an arrangement wherein cover member 24 is trapped between flanges 38 and retainer sections 44 to retain the cover member to the tray member. Rod-receiving openings 64,66 are provided corresponding to rod-receiving holes 50,52 of tray member 22. Cover cutouts 68 are provided beside end portions 62, associated with pairs of holes 48 of tray member 22, defining clearance for receipt thereinto of cable ties utilized on a similar tray stacked on top of tray assembly 20.
Cover tabs 70,72 are provided along side edges of cover member 24 spaced inwardly from cooperating retainer sections 62 of the cover member to reside inwardly of tray tabs 40 upon cover assembly and are easily manually engageable such as by protruding slightly beyond the side walls of the tray member as seen in FIGS. 2 and 3. In accordance with the present invention, cover tabs 70,72 define cantilever beams by reason of slots 74, with the slots extending sufficiently inwardly so that the cover tabs may be manually deflected upwardly sufficiently to rise above retainer sections 44 of tray tabs 40 during sliding of the cover member along tray member 22 during cover assembly or removal. By extending at least to the outer surface of tray side walls 34,36 while cooperating retainer sections 62 are recessed within the inner surface of tray tabs 40, end portions 76,78 of cover tabs 70,72 define side edges 80 adjacent inner side edges 42 of tray tabs 40 to abut thereagainst to restrain cover member 24 from inadvertent sliding with respect to tray member 22.
Recesses 82,84 are preferably formed in cover member 24 opposite the locations of cover tabs 70,72 permitting cover member 24 to be lifted off of tray member 22 as soon as cover member 24 is slid a sufficient distance to align a recess 82 or 84 with the retainer section 44 of the adjacent tray tab 40 opposite the location of corresponding cover tab 70 or 72. Optionally, only a single slot 74 extending to the interior of the cover member located adjacent one or each tray tab, will enable sufficient deflection of adjacent portions of the cover member thereat to ride over the tray tab thereat, especially if recesses 82,84 are provided requiring only a limited sliding prior to lifting of the cover member.
Cover member 24 thus can be fabricated by being cast in a planar sheet and stamped to define its dimensions and its features, all without any forming steps to bend portions thereof out of the plane, as in the prior art, and yet define features enabling retention to a tray member and also easy manual removal therefrom. The cover member is easily removable by being slid off either end of the tray member merely by upward deflection such as by the thumb of each cover tab in sequence. Alternatively the tray could be provided with only two tabs instead of four, whereby only one cover tab need be deflected during cover removal. The cover member may be made for example of polycarbonate having a thickness of about 0.030 inches, and the tray member may be stamped and formed from a sheet of anodized aluminum, for example.
The cover tab ends may optionally be shaped to facilitate manual engagement thereof. Variations and modifications may be devised that are within the spirit of the invention and the scope of the claims.