Tab and slot fiber optic fitting

A duct fitting for joining a plurality of duct sections of a wiring duct network comprising a fitting base and a fitting cover having corresponding tabs and slots for providing a simple assembly operation for fixing the cover to the base. The fitting base has tabs formed on the marginal edges of its sidewalls which cooperate with slots formed on flanges of the cover. The sidewalls of the base are flexed inwardly and then released to engage the tabs with the slots of the cover.

FIELD OF THE INVENTION 
The present invention relates to a fitting for joining wiring duct sections 
of a duct network, and more particularly to a tab and slot arrangement for 
a thermoplastic duct fitting. 
BACKGROUND OF THE INVENTION 
In the electronics and telecommunications industries duct networks are 
common for protecting and carrying various bundles of wires and fiber 
optic cables. Because the cables and wires are routed around corners and 
include numerous branches and splits in all different directions, the duct 
networks must include fittings that connect the multiple duct sections to 
provide for all the desired paths. The duct fittings are formed having 
many configurations such as T-shaped, right-angled and cross-shaped. 
Additionally, duct fittings often include removable covers to aid in 
installation and maintenance of the cables and wires. 
The following examples of duct fittings are known in the prior art: U.S. 
Pat. No. 834,828 to Lutz; U.S. Pat. No. 917,328 to Lutz; U.S. Pat. No. 
3,603,625 to Cottrell et al.; U.S. Pat. No. 4,951,716 to Tsunoda et al. 
and U.S. Pat. No. 5,161,580 to Klug. 
Many of the prior art duct fittings require complicated multi-step assembly 
operations that include a bending or folding action of a tab into a slot 
in order to engage the base with the fitting cover. Removal of these 
covers also includes similar complicated multi-step unfolding operations 
of the tabs. Other duct fittings and covers utilize engagement means such 
as velcro pads that do not adequately prevent inadvertent removal of the 
cover from the fitting in many of the uses for the duct networks. 
Furthermore, many of these prior art duct fittings are expensive to 
manufacture due to their complicated tab and slot arrangements with 
special side walls and intricately formed slots. 
SUMMARY OF THE INVENTION 
It is therefore an object of the present invention to provide an improved 
duct fitting for connecting multiple duct sections of a wiring duct 
network. 
It is another object of the present invention to provide a duct fitting 
with a removable cover that minimizes the assembly operations of the cover 
to the fitting while maintaining engagement strength to prevent 
inadvertent removal of the cover. 
It is still another object of the present invention to provide a duct 
fitting that is easier and cheaper to manufacture. 
A fitting for joining a plurality of duct sections of a cable duct network 
comprising a base member including a floor section, a plurality of 
sidewalls perpendicularly disposed and extending from an interior face of 
the floor section, a plurality of tabs formed on the marginal edges of the 
sidewalls and extending perpendicularly away from an exterior surface of 
the sidewalls, a cover member, engageable with the base member, having a 
lid section and including flange portions extending perpendicularly from 
an interior face of the lid section and a plurality of slots formed in the 
flange portions corresponding to the tabs of the base member.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
A duct fitting embodying the concept of the present invention is designated 
generally by the reference numeral 10 in the accompanying drawings. Duct 
fitting 10 includes a fitting base 12 and a fitting cover 28. Fitting base 
12 and fitting cover 28 are both thermo-formed into T-shaped pieces from 
sheets of plastic. 
Fitting base 12 has a floor section 14 with an interior face 16 and a pair 
of sidewalls 18 extending perpendicularly from the sides of floor section 
14 such that an interior surface 20 of each sidewall 18 is adjacent the 
interior face 16 of floor section 14. As can be seen in FIG. 1, sidewalls 
18 are formed on only the two sides of fitting base 12 for the T-shaped 
design that correspond to the sides of the stem of the "T" and the bottom 
of the top crossing portion. While sidewalls 18 are relatively stiff, they 
do have some resiliency and are flexible with respect to the floor section 
14. As can be seen in FIGS. 1 and 3, lips 22 are formed along the marginal 
edges of sidewalls 18 and are directed away from an exterior surface 24 of 
each sidewall 18. A number of tabs 26, in this case four, are formed at 
spaced distances along lips 22. Tabs 26 are extensions of lips 22 and are 
therefore also formed on the marginal edges of sidewalls 18 at right 
angles to and extending away from the exterior surface 24 of sidewalls 18. 
Fitting cover 28 has a lid section 30 with an interior face 32 and a pair 
of flange portions 34 extending perpendicularly from the sides of the 
interior face 32 of lid section 30 corresponding to sidewalls 18 of base 
12. A number of slots 36, in this case four, are formed at spaced 
distances along flange portions 34 corresponding to tabs 26 of the duct 
fitting base 12. 
As can be seen in FIGS. 4 and 5, tabs 26 cooperate with slots 36 to secure 
fitting cover 28 to fitting base 12 to comprise the duct fitting 10 for 
connecting a number of separate ducts together to route fiber optic cables 
or the like as part of a duct network. The slots 36 on the underside of 
the crossing top part of the "T" are initially slid onto corresponding 
tabs 26 and then the sidewalls 18 of the stem part of the "T" of base 12 
are flexed inwardly and released when tabs 26 are in position to engage 
corresponding slots 36 to secure cover 28 to base 12. 
In order to remove fitting cover 28, sidewalls 18 along the stem of the "T" 
are squeezed towards each other a sufficient distance to disengage tabs 26 
from slots 36. The fitting cover 28 is then slid in a direction to 
disengage the remaining tabs 26 from slots 36 on the underside of the 
crossing top part of the "T". This allows for quick and easy access to the 
interior of fitting 10 for maintenance rerouting of wires or for any other 
purpose. 
By having tabs 26 extending at right angles to sidewalls 18, slots 36 can 
be formed solely on the flange portions 34. Furthermore, with the tabs 26 
formed at the marginal edges of sidewalls 18, the flange portions 34 
extending perpendicularly from the edges of fitting cover 28 which contain 
slots 36, can be relatively short in length. This arrangement allows for a 
fitting that provides easy access to the interior of the fitting, and that 
is cheaper and easier to manufacture. 
The fitting base 12 and fitting cover 28 also include tongue portions 38 
extending from ends of fitting 10 that engage with other duct sections 40 
of the duct network. As can be seen in FIGS. 1 and 3, fitting 10 engages 
the duct sections 40 by creating an interlocking fit with duct sections 40 
by having tongues 38 formed offset either inwardly or outwardly from floor 
section 14. The inward offsetting of the tongue portions 38 that engage a 
floor of one of the duct sections to be joined allows for the floors of 
the duct sections 40 to be uniform to the fitting 10. The outward offset 
tongue portions 38 in turn cover the outer sidewalls of the joined duct 
sections 40. 
A support rib 44 is also formed on the outside of cover 28 as shown in FIG. 
4. Support rib 44 provides additional rigidity for the top cross part of 
the "T" of lid section 30. 
It can also be seen in FIG. 1 that standard duct covers 42 that cover the 
separate duct sections 40 can also be used to cover the crossing top part 
of the "T" as both the base 12 and cover 28 include a lip to engage a duct 
cover 42. 
While a T-shaped fitting has been shown and described above, there are a 
wide variety of shapes and configurations for duct fittings to which the 
tab and slot arrangement of the present invention would be applicable. 
A number of other possible embodiments of the tab and slot arrangement for 
a duct fitting are shown in FIGS. 6-10. In all of these other embodiments 
in order to form the fitting the sidewalls of the base are flexed inwardly 
and then released when the tabs are in position to engage the slots of the 
cover. It is noted that in the embodiments shown in FIGS. 6-10, the 
fitting base and fitting cover fully comprise the duct fitting without the 
need for any additional duct covers. 
FIG. 6 shows another embodiment of the present invention where tabs 56 of 
fitting base 54 engage slots 58 of fitting cover 52 to comprise an inside 
turning curved fitting 50. 
FIG. 7 shows another embodiment of the present invention in which tabs 66 
of fitting base 64 engage the slots 68 of fitting cover 62 to comprise an 
inside turning right-angled fitting 60. 
FIG. 8 shows yet another embodiment of the present invention in which tabs 
76 of fitting base 74 engage slots 78 of fitting cover 72 to comprise 
outside turning curved fitting 70. 
FIG. 9 shows another embodiment of the present invention in which tabs 86 
of fitting base 84 engage slots 88 of fitting cover 82 to form outside 
turning right-angled fitting 80. 
FIG. 10 shows another embodiment of the present invention in which tabs 96 
of fitting base 94 engage slots 98 of fitting cover 92 to form 
cross-shaped fitting 90. 
While the particular embodiments of the present invention have been shown 
and described, it will be obvious to those skilled in the art the changes 
and modifications may be made without departing from the invention and its 
broader aspects. The matter set forth in the foregoing description and 
accompanying drawings is offered by way of illustration only and not as a 
limitation. The actual scope of the invention is intended to be defined in 
the following claims when viewed in their proper perspective based on the 
prior art.