Ducting system for wiring having channel alignment interface members

A ducting system for electrical wiring or the like including elongated channels and channel covers and prefabricated channel interface assemblies adapted for rapid non-defacing installation without resort to special tools or precision assembly techniques. The interface assemblies are comprised of alignment members which are adapted to engage two or more channels thereby to automatically position the channels in a predetermined relationship. More specifically, projections are provided on the alignment members which are received within recesses on the ends of the duct channels thereby functioning to properly and automatically orient the several duct channels upon system assembly. The interface assemblies further include removable cover means which bridge and conceal the respective ends of the channels and channel covers thereby eliminating precision cutting of the duct sections.

This invention relates generally to duct systems for the containment of 
electrical wiring, conduits, or other similar objects and, in particular, 
to a duct system having interface and terminal components adapted to 
exposed installation on pre-existing structures or in applications where 
frequent or subsequent wiring changes are contemplated. The uses for 
electrical wiring, both in the home and in business, have been steadily 
increasing in recent years. Applications now include, for example, 
telephone, intercom, TV and video, hi-fi, burglar and other alarms, 
computer and general control systems. The expanding and ever-changing 
nature of these uses effectively precludes permanent in-wall conduit 
wiring installed during initial building construction. And, in most 
instances, subsequent in-wall installation is often destructive and 
prohibitively expensive. 
Wiring ducts have been known for many years. Such systems, however, due to 
various limitations are often unsuitable or undesirable for many 
applications. Certain ducts, for example, are adapted for installation 
only in limited, special environments. The duct system shown in U.S. Pat. 
No. 3,471,629 to O'Leary FIG. 28, is such a duct, incorporating parallel 
spaced flanges specifically designed to mount the duct to room dividers or 
partitions. The O'Leary duct is therefore unsuitable for general in-room 
installation. 
Present known duct systems generally utilize screws or similar anchors to 
secure the duct to the desired surfaces. Examples include Schwab, U.S. 
Pat. Nos. 4,166,195; 4,136,257; Taylor, U.S. Pat. No. 3,909,505; or Pollak 
et al, U.S. Pat. No. 3,697,667. These duct systems variously require 
anchoring through bottom conduit face, flanges integral to the duct, or 
separate clamp elements. Each relies upon a nail or screw driven into the 
mounting surface for attachment. These ducts involve relatively difficult 
and time consuming installations. In addition, nail or screw installations 
in the respective mounting surfaces will permanently mar the mounting 
surface and, consequently, unless the installation is permanent, 
subsequent duct system reconfiguration will necessarily expose the marred 
former mounting surface. Removal or reconfiguration of the ducts requires 
time consuming and expensive hole patching to restore the previous 
mounting surface to its original, pre-installation condition. The duct of 
this invention, by contrast, utilizes a pre-applied adhesive backing which 
facilitates rapid anchorless installation. Since no holes are required, 
this duct can readily and rapidly be reconfigured with a minimum of damage 
to abandoned mounting surfaces. 
Difficulties with installation of convention ducts are not limited merely 
to the above discussed mounting considerations. Installation of a complete 
duct system also requires the measuring, cutting and fitting of duct 
channels with various interface assemblies including elbows, inside and 
outside corners, tees, splices and ends. Conventional systems generally 
require that each individual length of duct channel be accurately measured 
and neatly and squarely severed to permit proper abutment with mating 
corner or other interface assemblies. In D'Esopo, U.S. Pat. No. 3,404,706, 
for example, inaccurate or non-square cutting may result in the channels 
not fitting or, at least, in a sloppy, unsightly installation having 
visible gaps and rough edges. Other systems, such as shown in O'Leary, 
U.S. Pat. No. 3,471,629, which utilize no corner interface assemblies, 
require precisely cut and mitred corners to achieve an accurate and 
acceptable appearing junction. The duct system of this invention, by 
contrast, employs pre-fabricated assemblies adapted to conceal duct 
channel and channel cover ends thereby obviating precisely measured and 
cut or mitred ends as required by conventional duct systems and 
simplyfying installation to a degree where an unskilled homeowner can 
produce a professional-appearing installation with simple tools. 
In addition, the duct channel of this invention incorporates a bottom 
T-groove and a series of ridges in the channel sidewalls adapted to create 
a highly flexible mounting capability in which a wide variety of wire 
retainers, component carriers, terminal points, printed circuit boards, 
jacks, switches or duct channel expanders can be affixed therein. In this 
manner, the duct system of this invention functions not merely as a 
raceway to conceal and retain wires, but as a total containment system for 
interfacing physically separated apparatus. 
An object of this invention, therefore, is an economical ducting system 
suitable for in-room installation by unskilled individuals in existing 
buildings and structures. Attachment is preferably accomplished with a 
taped adhesive pre-applied to the duct channels to facilitate rapid and 
effortless installation while minimizing marring or damaging of the 
underlying attachment surface inherent in ducts anchored by nails or 
screws. 
Duct channels, covers, and interface assemblies are preferably fabricated, 
by extrusion or molding, from economical and easy to handle material such 
as PVC plastic. Channels include a T-groove and ridges which create a 
flexible retention scheme whereby wire retainers, terminal or component 
carriers, jacks, switches and the like may be positioned and retained 
within, or adjacent, an associated duct channel span. The duct system will 
preferably include such component carriers and a complete family of 
interface assemblies, such as elbows, inside and outside corners, tees, 
splices and ends, in combination with straight duct channel segments to 
facilitate flexible installations adapted to particular user requirements. 
Channel and interface assembly covers will be easily removed and 
reinstalled to expedite rerouting or additions to the electrical cables 
therein. Duct interface assemblies will eliminate the necessity of 
accurately measuring and cutting duct channels and channel covers. In 
addition, user fabricated precision mitred corners or elbows will not be 
required. The system will be suited to subsequent expansion or deletion of 
duct routes in response to changing user needs.

PREFERRED EMBODIMENT 
FIG. 1 illustrates a typical portion of the duct of this invention wherein 
a vertical duct segment 10 is shown intersecting a generally horizontal 
span 12 of ducting to form a `tee` junction. A duct interface assembly 14 
comprising alignment member 16 and interface cover 18 joins and 
decoratively covers exposed channel ends 20 and channel cover ends 22. A 
complete installation of this ducting may include multiple spans of 
ducting, such as shown at 10 and 12, interconnected by appropriate 
interface assemblies, such as the `tee` assembly shown at 14, to link the 
multiple terminal or mid-span locations. 
Each duct span includes a length of duct channel 24 and a generally equal 
length of duct channel cover 26. Channels 24 and covers 26 are extruded, 
preferably of a PVC material and supplied in standard lengths which the 
user can readily cut as required to meet his specific installation needs. 
As best seen in FIG. 2, channel 24 comprises a bottom 28 and a pair of 
spaced sidewalls 30 defining a generally U-shaped cross-section. A 
double-backed adhesive strip or tape 32 is positioned along the outer face 
of bottom 28. Tape 32 is provided with a protective covering sheet which, 
when peeled off and removed, exposes the adhesive material to permit 
attachment of channel 24 to a wall or other surface. 
A pair of complementary L-shaped ridges 34 extend inwardly generally from 
the center of bottom 28 and define a `T` groove 36 therebetween running 
longitudinally along the bottom of the channel. Each sidewall 30 contains 
a pair of inward facing parallel retention ridges 38 positioned generally 
adjacent the upper free edge of wall 30. Clip or component carrier 
retention slots 40 are defined between respective ridges 38 on each 
sidewall. Rectangular cover retention recesses 42 are provided in the 
lower outer sidewall surfaces adjacent bottom 28. 
Channel cover 26 comprises a top 44 and two spaced parallel cover sides 46. 
Opposed lips or flanges 48 extend inwardly from respective lower free 
edges of sides 46. Interface cover engaging recesses 50 are provided along 
the lower outer surface of walls 46. A non-uniform relief or pattern of 
grooves is otherwise provided on the outward facing surfaces of cover 26 
to enhance the esthetic appearance of the cover. 
The ducting system of this invention includes a `family` of interface 
assemblies which are adapted to engage and interconnect individual duct 
channel spans. These assemblies permit the `contouring` of the duct system 
around corners where straight linear installations are either impractical 
or impossible as well as the splicing of multiple standard length channel 
spans where longer overall duct lengths are required. Typical interface 
assemblies of this type include right angle inside 52 and outside 54 
corners and elbows 56. In addition, multiple channel interface assemblies, 
such as 3-channel `tee`s' or `wye`s' or 4-channel cross-intersections, add 
system flexibilty by permitting duct branching and crossing. Duct channel 
`end` members 58, as shown in FIG. 1, and terminal or component break-outs 
60, as shown in FIG. 6, also are contemplated. 
FIG. 1 illustrates a typical interface assembly of this invention. 
Interface assembly 14 includes `tee` alignment member 16 and `tee` 
interface cover 18. Alignment member 16 is a rigid molded plastic piece 
having projections 62 which are inserted into T-grooves 36 (FIG. 2) in 
friction engagement with ridges 34. Alignment members serve to properly 
position respective channel ends 20 with respect to one another during 
installation and to maintain this relationship thereafter. Alignment 
members are uniquely dimensioned for each different interface assembly 
configuration. Thus, the number and positioning of projections 62 from any 
given alignment member will characterize the configuration of the 
resulting duct interface. For example, the alignment member 16 shown in 
FIG. 1 includes a pair of oppositely facing projections 62 positioned on a 
common longitudinal axis and a third projection (not shown) disposed 
perpendicularly midway therebetween. The configuration establishes the 
`tee` interface assembly shown. Other alignment members, including 
projections 62, are illustrated in FIG. 5. Inside and outside corner, 
elbow and splice alignment members are shown and respectively identified 
by reference numbers 64, 66, 68 and 70. Duct end members 58 and terminal 
or component mid-span breakouts 60 do not generally require alignment 
members as only a single channel span or end is associated with each of 
these components. 
Interface covers 18 are, similarly, uniquely dimensioned to achieve the 
desired channel interface. Thus, a `tee` cover 18 is combined with a 
corresponding `tee` alignment member 16 to create a `tee` interface 
assembly. As illustrated in FIG. 3, `tee` interface cover 18 has a 
substantially U-shaped cross-section dimensioned to closely fit over 
channel covers 26. One or more inwardly facing ridges or flanges 72 are 
provided along the opposed bottom edges of interface cover 18. These 
ridges or flanges 72 serve to retain cover 18 by mating with recesses 50 
in duct channel covers 26. Interface covers 18 are further dimensioned to 
interconnect and overlap both the respective duct channels and channel 
covers thereby assuring proper cover to cover engagement and a decorative 
assembly completely enclosing the channel interface region defined between 
respective channel ends 20. 
A central feature of the duct of this invention is found in the simplicity 
of installation by the unskilled and uninitiated where precision cutting, 
skilled assembly techniques or special tools are unnecessary. First, a 
ducting route interconnecting the desired cable terminal points is chosen 
which may include any combination of linear ducting spans and available 
interface assemblies. The distances between adjacent interface assemblies 
are measured and standard extruded duct channels 24 and channel covers 26 
are cut accordingly. Corresponding or mating duct channels and channel 
covers are cut to substantially the same length. Precision cutting or 
squaring of end surfaces is not required as the ends of both duct channel 
24 and channel cover 26 are ultimately concealed by the interface cover 
18. Thus, a common or similar inexpensive and readily available cutting 
may be used. 
Once cut to proper length, channels 24 are readily installed simply by 
peeling back the protective backing, thereby exposing the adhesive surface 
32, and by pressing the duct channel 24 against the desired wall or other 
surface. Positioning of adjacent duct channels at interface assemblies is 
facilitated by use of alignment members 16, or 64, 66, 68, 70 (FIG. 5). 
Specifically, alignment member projections 62 are urged into respective 
T-grooves 36 at channel ends 20 prior to securing the channels to the 
surface. Alternatively, an alignment member may be inserted into the 
T-groove 36 end of a previously secured channel prior to attachment of the 
remaining channels comprising the interface assembly junction. 
Subsequently, each of the remaining channels may, in turn, be positioned 
with respect to the interface by inserting alignment member projections 62 
into successive channel T-grooves 36. In this manner, the ducting of this 
invention can be rapidly and accurately assembled from one terminus to 
another by successively and alternately mounting duct channel segments and 
interface alignment members. Multiple channel `tee` or `wye` interfaces 
are installed in the same manner except that each of the separate branches 
is installed independently to its respective terminus. 
Terminal or component carriers 74, as shown in FIG. 6, are positioned along 
the duct channel as desired. Ridges 38 and T-groove 36 are adapted to 
provide flexible mounting alternatives to meet the requirements for 
differing terminal or component carrier option. For example, a carrier may 
be positioned between opposing slots 40 in a similar fashion to that shown 
for cable retention clip 77, FIG. 2. Alternatively, a carrier may be 
retained within T-groove 36 and, if desired, `three-point` attachment can 
be achieved by dimensioning the carrier to urge it into engagement with 
lower ridges 34 from below or, the carrier may be snapped into slots 40 
similar to that shown for retention clip 80, FIG. 3. 
The above described network of duct channels 24, interface alignment 
members 16, 64, 66, 68, 70 and terminal or component carriers 74, is now 
ready for initial cable installation. Wires and cables 76 are routed 
through channels 24 between the various duct termini and component 
carriers 74 as required. Flat cable retainers 77, as shown in FIGS. 1 and 
2, may be snapped into parallel slots 40 at intervals along channels 24 to 
dress and retain wires and cables within the channel interior 78 prior to 
initial installation of channel covers 26 or, subsequently, when these 
covers are removed for cable rewiring or servicing. The combined 
flexibility of channel walls 30 and cable retainers 77 facilitates the 
rapid placement and removal of these retainers as may be necessary during 
subsequent system alteration. 
An alternate three-point retainer 80 is shown in FIG. 3. This retainer 
includes a flat member 82, the ends of which are retained within opposed 
slots 40 in channel wall 30 in substantially the same manner as retainer 
77. Flat member 82 includes a perpendicular leg 84 projecting downwardly 
from the center of the flat region and into T-groove 36 of the duct 
channel 24. As shown in FIG. 3, a pair of opposed feet 86 extend outwardly 
from the bottom of leg 84 in generally parallel relation to the flat upper 
member 82 and frictionally engage the L-shaped ridges 34 forming T-groove 
36. 
The installation of retainer 80 is accomplished by rotation 90 degrees from 
the position illustrated in FIG. 3. Leg 84 carrying opposed feet 86 slips 
easily into T-groove 36 between ridges 34. As retainer 80 is rotated 90 
degrees to the position shown in FIG. 3, feet 86 are brought into 
frictional engagement with the portions of ridges 34 defining T-groove 36. 
Similarly, the distal ends of flat member 82 of the retainer are brought 
into frictional engagement with the ridges 38 defining opposed slots 40 at 
the upper end of duct 24 as the retainer 80 is rotated into the FIG. 3 
position. The three-point retainer 80, after installation, divides the 
channel interior 78 into two generally equivalent half-channels and may be 
used to segregate or identify certain wires or cables. 
Final duct assembly simply requires that the channel covers 26 be snapped 
onto the respective channels 24. As illustrated in FIG. 3, cover ridges or 
flanges 48 engage channel recesses 42 to provide secure retention of the 
cover. Finally, interface assembly covers 18 are similarly snapped into 
position thereby covering the alignment member, duct channel and channel 
cover ends, and wires and cables therein. Interface cover ridges 72 engage 
channel cover recesses 50 to effect interface cover retention. 
It can be appreciated from the above description, that the duct system of 
this invention not only can be simply installed by the average homeowner 
without special tools, but that the wiring therein can be instantaneously 
re-accessed merely by unsnapping interface and channel covers. In this 
manner, the electrical cables can be quickly reached for service or 
rewired as electrical system requirements change. In addition, duct 
channel T-groove and sidewall ridges in the duct channel facilitate a wide 
range of cable retention clip and terminal or component carrier mounting 
options, thereby creating a complete overall duct system wherein 
additional, bulky and non-matching component or interface boxes are not 
required. 
Further, the ease of installing or removing channels without the use of 
screws or nails which deface the mounting surface facilitates the removal 
of unused functionally obsolete portions of the duct system as well as 
system expansion to meet growing needs.