Terminator connector fitting for electrical box and conduit system

A terminator fitting useful for connecting corrugated tubing to an electrical outlet box and including a cylindrical collar having first and second ends and a rib projecting radially inwardly from the collar for engaging an external rib on corrugated tubing placed within the collar. The collar carries circumferentially-spaced, axially projecting projections on one of its ends, with each such projection including a wedge-shaped free end portion. Each wedge-shaped end portion is joined to the first end of the collar by a web portion. The web portion, free end portion and collar define a groove for engaging the side wall of an outlet box when the arcuate projections are forced through an opening in the box to secure the fitting in the box. A plurality of blocking flanges are included in the terminator fitting with each blocking flange extending in a circumferential direction from a lateral edge of one of the wedge-shaped free end portions.

FIELD OF THE INVENTION 
This invention relates to an electrical conduit system which includes a 
flexible corrugated conduit, an electrical outlet box of synthetic resin 
and a terminator connector fitting by which the corrugated conduit is 
connected to the electrical outlet box. The invention more specifically 
relates, in one aspect and without limitation, to a novel terminator 
connector fitting which is snapped into an opening in an electrical outlet 
box, and is used to connect to the outlet box, a flexible corrugated 
conduit which functions as a raceway for electrical conductors extended 
into the box and connected to terminals therewithin. 
BACKGROUND OF THE INVENTION 
1. Brief Description of the Prior Art 
U.S. Pat. No. 4,494,779, assigned to the assignee of the present invention, 
describes a terminator connector fitting by which corrugated conduit is 
connected to an electrical outlet box. The terminator fitting and the 
corrugated conduit are made of a synthetic resin material, and are 
characterized by flexibility and limited resiliency. The terminator 
fitting described in U.S. Pat. No. 4,494,779 is adapted to be forced, as 
facilitated by the resilient yielding of parts of the fitting, partially 
through an opening in a side wall of an electrical outlet box. The 
terminator fitting then snaps into position as the portion of the box 
defining this opening engages a recess or groove formed in the terminator 
fitting. 
To facilitate insertion of a portion of the terminator fitting into the 
opening through the wall of the box, the terminator fitting includes a 
pair of semi-cylindrical collars which can be interconnected, and each of 
which carries two spaced, box-engaging projections which extend axially 
from each of the collars and are yieldable radially inwardly sufficiently 
to permit them to be forced through the opening in the electrical outlet 
box. The inner side of each of the semi-cylindrical collars is grooved and 
ribbed to mate with, and engage, corrugations carried on a corrugated 
conduit to be connected to the electrical outlet box. Each box-engaging 
projection includes a wedge-shaped free end portion, and also a web 
portion by which the wedge-shaped free end portion is connected to the 
respective semi-cylindrical collar upon which it is carried. Each 
wedge-shaped end portion, associated web portion, and the semi-cylindrical 
collar to which the respective web portion is connected, define an arcuate 
channel, groove or relief for receiving and engaging the portion of the 
wall of the electrical box which surrounds and defines the opening into 
which the terminator fitting is snapped in assembling the system. 
Each of the box-engaging projections is spaced from the adjacent 
box-engaging projection by a substantial circumferential distance, 
considered as an arc of a circle, and this spacing serves several 
functions. First, it requires less material when the terminator fitting is 
molded of plastic. More importantly, the spacing allows the arcuate 
dimension of each of the box-engaging projections to be sufficiently small 
that the respective projection can flex or bend about the web portion by 
which the respective box-engaging projection is connected to the 
semi-cylindrical collar upon which it is carried. Further, in providing 
the circumferential space between adjacent box-engaging projections, each 
of these projections can flex or bend in a radially inwardly direction as 
much as is required to permit it to be passed through the generally 
circular opening in an electrical outlet box. Such opening has a diametric 
dimension which is less than the outside diameter of the circle which 
passes through, and includes the largest outside dimension of the several 
box-engaging arcuate projections when they are collectively considered as 
a cylindrical array and are in a relaxed, undeflected condition. Without 
such spacing between the box-engaging projections, they would interfere 
with each other as they tend to flex radially inwardly, and such radially 
inward flexure would be limited, in many cases, to an extent such that the 
terminator fitting could not be forced through the opening in the wall of 
the electrical outlet box. 
Though the necessary freedom of flexing movement is gained in the 
terminator fitting by providing the described spacing between adjacent 
box-engaging projections carried on each of the semi-cylindrical collars, 
it has been found that in the case of some electrical conductor 
installations where wires are extended through the corrugated conduit 
engaged by the terminator fitting and into the electrical outlet box, a 
problem comes to exist as a result of the spacing between the box-engaging 
projections. This problem is that the portions of the electrical 
conductors located inside the electrical outlet box, after passing through 
the corrugated conduit and the terminator fitting, tend to pull back into 
the space or gap between adjacent box-engaging projections, and to become 
restricted in their freedom of movement at the free end portions of the 
electrical conductors and wires. This makes it more difficult to 
manipulate the conductors as necessary for connection to terminals within 
the box. Importantly also, on occasion the electrical conductors, after 
connection within the electrical outlet box, will be pulled into the gap 
or space between adjacent box-engaging projections of the terminator 
fitting, and will work against the side edges of one of the projections 
until the insulation on the conductor is destroyed. Occasionally the 
conductor is completely severed. 
For all of the foregoing reasons, the terminator connector fitting 
described in U.S. Pat. No. 4,494,779 works well in many installations, and 
provides a highly useful fitting which can be quickly installed in an 
electrical outlet box to establish a connection between a corrugated 
conduit and the box, but such terminator fittings nevertheless do not 
provide optimum performance in all modes of usage. 
2. Brief Description of the Present Invention 
This invention provides a terminator fitting of synthetic resin which can 
be quickly snapped into an opening provided in an electrical outlet box, 
and there function to retain a corrugated conduit in position relative to 
the box and the opening so that a system can thus be constructed which 
more effectively guides and protects electrical conductors used in a 
system of electrical service. Although the terminator fitting preferably, 
and most frequently, will be used with an electrical outlet box made of a 
synthetic resin material, and with a corrugated conduit also made of such 
material, the terminator fitting can be employed with metallic electrical 
outlet boxes. 
Broadly described, the terminator fitting of the invention preferably 
includes a pair of semi-cylindrical collars of substantially identical 
dimension, and which are preferably, but not necessarily, interconnected 
by a thin hinge strap which can be molded integrally with the 
semi-cylindrical synthetic resin collars. The collars cooperate, in use, 
to define, in collective array, a cylinder having a greater outside 
diameter than the diameter of the opening in the electrical outlet box 
into which the terminator fitting is to be inserted. In an alternative 
form of the invention, the two collars may be molded as a single integral 
unit of cylindrical form. 
At the radially inner side of the two semi-cylindrical collars, each collar 
carries a projection which may, in a preferred embodiment, be in the form 
of an arcuate rib. The projection is adapted to interfit with and engage 
the corrugations carried on the exterior of a flexible conduit which is to 
be connected to the electrical outlet box. As an alternative to such 
conduit-engaging arcuate ribs, the collars may instead carry yieldable, 
flexible tongues or tabs, by which engagement with the described 
corrugated conduit can be effected. 
Each one of the semi-cylindrical collars in the pair carries two 
circumferentially spaced, box-engaging, arcuate projections. These 
projections extend axially from one end of each of the semi-cylindrical 
collars. In being molded of a resilient synthetic resin and formed 
integrally with the collars, the projections are yieldable in a radially 
inward direction to permit these projections to be displaced by a 
sufficient amount to be forced through the circular opening in the side 
wall of an electrical outlet box. Each of the box-engaging projections 
includes a wedge-shaped free end portion at its terminus spaced from the 
respective semi-cylindrical collar upon which it is carried, and each 
projection also includes a hinging web portion by which the wedge-shaped 
free end portion is connected to the respective semi-cylindrical collar 
upon which it is carried. Each of the wedge-shaped end portions defines, 
with the respective semi-cylindrical collar, an arcuate channel, relief or 
groove extending circumferentially across the respective box-engaging 
projection. The channel or relief thus defined adjacent the axially inner 
side of each semi-cylindrical collar is dimensioned for receiving, and 
relatively snugly engaging, the portion of the wall of the electrical 
outlet box which surrounds and defines the opening into which the 
terminator fitting is snapped during the assembly of the system. 
The present invention provides as one improvement in a terminator fitting 
structure, a first blocking flange which is molded integrally to each of 
one of the two box-engaging projections on each collar at a location 
adjacent an axial edge thereof. This first blocking flange extends from 
the respective box-engaging projection upon which it is mounted in a 
circumferential direction preferably to a point where the free end of the 
blocking flange lies immediately adjacent an axial edge of the other of 
the two box-engaging projections carried on the same respective 
semi-cylindrical collar. Each blocking flange thus substantially fills one 
of the curcumferential gaps or spaces between the two adjacent 
box-engaging projections carried on the semi-cylindrical collar. Yet, it 
is preferably free to flex inwardly as may be needed to allow it to slide 
beneath one of the box-engaging projections as the terminator fitting is 
being snapped into the opening into which it is to be received when 
mounted in the electrical outlet box. 
Carried on the second of the two box-engaging projections mounted on the 
respective semi-cylindrical collar is a second, narrower blocking flange 
which also has one of its ends molded integrally with, and secured beneath 
an edge portion of, this second box-engaging projection. This blocking 
flange also extends circumferentially from the axial edge portion of this 
second box-engaging projection to a location where it is adjacent the 
axial edge of one of the box-engaging projections carried on the second or 
other of the semi-cylindrical collars. 
Both semi-cylindrical collars, box-engaging projections and the blocking 
flanges carried thereon are identically constructed. The second of the 
semi-cylindrical collars and its respective associated box-engaging 
projections and blocking flanges is thus described as being constructed in 
accordance with the description appearing above as characterizing one of 
the semi-cylindrical collars and its associated pair of projections. 
An important advantage of the present invention is that the insulated 
electrical conductors, which extend through a corrugated conduit engaged 
by the terminator fitting and into an electrical outlet box in which the 
fitting is mounted, cannot be pulled back into the gap between adjacent 
box-engaging projections carried on each of the semi-cylindrical collars, 
and there be sawed back and forth to destroy the integrity of the 
insulation on the electrical conductor, or perhaps cause a complete break 
to occur in the conductor. The spaces between adjacent box-engaging 
projections are effectively blocked by the blocking flanges which are 
provided. Yet these flanges are positioned and oriented in such a way with 
respect to the remainder of the structure that they do not interfere in 
any way with the inward flexure of the box-engaging projections, which 
inward flexure is required in order to permit the terminator fitting to be 
snapped into the opening in the side of the electrical outlet box. 
Another important object of the invention is to provide a terminator 
fitting which is improved in its construction in that it does not 
interfere with, or cause damage to, electrical conductors passed 
therethrough and into the interior of an electrical outlet box in which 
the fitting is mounted. 
An additional object of the invention is to provide an improved terminator 
fitting which can be quickly and easily snapped into an electrical outlet 
box and concurrently grip and engage a corrugated flexible conduit through 
which an electrical conductor is to be extended to reach to, and inside 
of, the electrical outlet box, which terminator fitting is characterized 
by a long and trouble-free operating life. 
Additional objects and advantages will become apparent as the following 
detailed description of the invention is read in conjunction with the 
accompanying drawings which illustrated a preferred embodiment of the 
invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION 
In a broad aspect, the present invention relates to an improved electrical 
service system in which a terminator fitting 4 is engaged with an 
electrical outlet box 6 by insertion in a circular opening 7 therethrough, 
and functions to connect a flexible corrugated conduit 8 to the box. This 
system, as illustrated in FIG. 7, further includes insulated electrical 
conductors 9 which extend through the conduit 8, through the terminator 
fitting 4 and into the interior of the box 6. 
The terminator fitting 4, in a preferred form, includes a pair of 
semi-cylindrical collars 10 and 12 which are substantially identical in 
configuration. In another, less preferred form, the collars may be a 
single, unitary cylindrical collar element. The collars 10 and 12 are 
preferably constructed of a suitable synthetic resin, such as 
polyphenyleneoxide base resin or a polyphenylene ether copolymer, and each 
includes a convex semi-cylindrical external surface 14 and a concave 
semi-cylindrical internal surface 16. Carried on the inner surface 16 of 
each of the semi-cylindrical collars 10 and 12 is at least one radially 
inwardly projecting arcuate locking rib or ridge 15 which is axially 
spaced from an arcuate stop flange 19 and is radially dimensioned to 
engage one of the annular grooves formed around the exterior of a flexible 
corrugated conduit 8. Such conduit 8 is typically used in electrical 
service systems for containing, and acting as a raceway for, one or more 
flexible electrical conductors, as illustrated at 9 in FIG. 7. 
The semi-cylindrical collars 10 and 12 are preferably interconnected by a 
relatively narrow flexible strap 18 which is molded integrally with the 
two collars, and has its opposite ends connected to the respective collars 
adjacent the diametric plane which is defined by the relatively broad 
axial edge portions 17 of each of the two semi-cylindrical collars. Thus, 
the collars can be folded out with respect to each other so as to occupy 
the position illustrated in FIG. 6 of the drawings. Alternatively, the two 
hingedly interconnected collars can be folded together to occupy the 
positions shown in FIG. 3 of the drawings in which the relatively broad 
axial edge portions 17 of the collars abut each other along the described 
diametric plane so as to conjointly form a cylindrical figure of the sort 
shown in FIGS. 1-3 of the drawings. 
It should be pointed out that in a preferred method of constructing the 
terminator fitting of the invention, the fitting is formed by an injection 
molding procedure in which all of the parts of the fitting are integrally 
formed with all other parts. As earlier noted, however, the two collars 10 
and 12 need not necessarily be interconnected to each other by a strap, 
and it is also possible to construct the terminator fitting 4 with a 
single, integrally molded cylindrical unit replacing the two 
semi-cylindrical collars. 
Each pair of the semi-cylindrical collars 10 and 12 carries a pair of 
spaced, axially projecting box-engaging projections. For clarity of 
discussion and illustration, the two box-engaging projections carried on 
the collar 12 are denominated by reference numerals 20 and 22, whereas the 
box-engaging projections carried on the semi-cylindrical collar 10 are 
denominated by reference numerals 24 and 26. As will be better understood 
as the following description proceeds, the box-engaging projections 20 and 
26 are substantially identical to each other in construction, 
configuration and function, and the box-engaging projections 22 and 24 are 
substantially identical to each other in construction, configuration and 
function. 
Each of the box engaging projections 20-26 is of arcuate, transverse 
cross-sectional configuration, with each being formed substantially on an 
arc of a circle. Such arc is preferably slightly less than a quadrant of a 
circle, or, stated differently, subtends slightly less than 90.degree.. It 
will be noted that the arcuate box-engaging projection 20 is separated 
from the box-engaging projection 22 by a circumferential space or gap 28, 
and that the box-engaging projections 24 and 26 are also separated from 
each other by a similar circumferential space or gap 30. The projection 20 
is also spaced from the projection 24 by an intervening gap 31, and a gap 
33 separates the projection 22 from the projection 26. As previously 
mentioned, each of the arcuate box-engaging projections 20-26 extends in 
an axial direction from one end, hereinafter termed the axially inner end, 
of the respective semi-cylindrical collar 10 or 12 upon which it is 
carried. The box-engaging projections 20-26 in collective array form a 
generally cylindrical figure. 
Each of the arcuate box-engaging projections 20-26 is joined by a web 
portion 32 to the respective semi-cylindrical collar 10 or 12 upon which 
it is mounted. The web portion 32 has a relatively thin radial dimension, 
and a relatively narrow circumferential dimension, to thus permit the 
remaining part of the respective box-engaging projection to flex and pivot 
radially inwardly as the terminator fitting is pressed into its operative 
position within the opening of an electrical outlet box as shown in FIG. 
4. Stated differently, each of the box-engaging projections 20-26, as the 
outer surface thereof encounters the defining boundary of the circular 
opening through the box, can undergo radially inward movement by flexure 
about the hinge constituted by the interconnecting web portion 32. The 
resilience of the synthetic resin of which the terminator fitting 4 is 
constructed will then cause the respective box-engaging projections 20-26 
to spring back into their box-engaging positions. These positions are 
illustrated in FIG. 4 after the free inner ends of the projections, which 
are of a wedge-shaped configuration, have passed through the box opening. 
The several wedge-shaped inner ends of the box-engaging projections 20-26 
are denominated in the several figures of the drawings by the respective 
reference numerals 20a-26a. 
It will be noted in referring to FIGS. 1 and 2 that the circumferential 
width of the web portion 32 by which each of the box-engaging projections 
20-26 is joined to the respective semi-cylindrical collars 10 or 12 upon 
which the respective projection is carried is substantially less than the 
circumferential width of the wedge-shaped free end portion of the 
respective projection. The reduced circumferential width and reduced 
radial thickness of the web portions 32 facilitate the required flexing 
movement of the box-engaging projections as the terminator fitting is 
snapped into the opening of the synthetic resin electrical outlet box 6. 
An important feature of the terminator fitting 4 is the provision of a 
plurality of blocking flanges which prevent electrical conductors 9 
extended through the fitting and into the electrical outlet box 6 from 
being pulled between the circumferentially-spaced, box-engaging 
projections 20-26. The circumferential spaces 28, 30, 31 and 33 at these 
locations between the several projections 20-26 have previously presented 
the problem of permitting insulated electrical conductors 9 passed through 
the flexible 8 conduit and the fitting 4 and into an electrical outlet box 
6 to become jammed in such spaces. The conductors 9 then chafe and wear as 
they undergo any movement so as to sever the insulation and, in extreme 
instances, to even sever the electrical conductor. In some cases, jamming 
of an insulated electrical conductor 9 into the circumferential space 
between two of the flexible box-engaging projections 20-26 has interfered 
with the ability to push or pull and manipulate the conductor 9 so as to 
effect connection to a contact within the electrical outlet box 6, or to 
remove slack from the conductor where such slack exists within the box and 
during the course of installation of the system. 
As illustrated in the drawings, and particularly in FIGS. 3, 6 and 7, each 
of the box-engaging projections 20 and 26 carries an elongated arcuate 
blocking flange 20b and 26b, respectively. The blocking flanges 20b and 
26b are molded integrally to the underside of the respective box-engaging 
projections 20 and 26 near the axial side or edge thereof. In projecting 
circumferentially away from this axial side or edge, each of the blocking 
flanges 20b and 26b project across at least a major portion of the 
intervening circumferential space, and preferably to a location 
immediately adjacent one side of the other box-engaging projection in the 
pair carried on the same one of the respective semi-cylindrical collars 10 
and 12. The blocking flanges 20b and 26b will be perceived to be 
positioned so that, as the several box-engaging projections 20-26 undergo 
radially inward movement as they are pressed through the opening in an 
electrical outlet box 6, the blocking flanges can pass clear of the 
respective box-engaging projections by extending below the radially inner 
side thereof with a very slight clearance existing along the radially 
inner surface of the respective projection 22 or 24 and the adjacent 
blocking flange. 
In similar fashion, the box-engaging projections 22 and 24 carry 
circumferentially extending blocking flanges 22b and 24b, respectively, as 
best illustrated in FIGS. 3 and 6. The blocking flanges 22b and 24b are 
molded to the underside of the respective box-engaging projection 22 and 
24, and adjacent one edge thereof. The flanges 22b and 24b project 
circumferentially from the respective box-engaging projection toward the 
radially inner surface of the adjacent one of the several box-engaging 
projections. 
As will be perceived in referring to FIG. 3, at a time, for example, when 
the terminator fitting 4 is to be pressed through the opening in the wall 
of an electrical outlet box, the arcuate box-engaging projections 22 and 
24 flex inwardly about the web portions 32 by which these projections are 
joined to the semi-cylindrical collars 10 and 12 upon which they are 
carried. At this time, the blocking flange 22b will move circumferentially 
along the inner side of the box-engaging projection 26 and will not 
prevent either the box-engaging projection 26 or the box-engaging 
projection 22 from flexing radially inwardly. The same relationship exist 
with respect to the box-engaging projection 24, its blocking flange 24b 
and the box-engaging projection 20. 
In the utilization of the illustrated embodiment of the terminator fitting 
4, the two semi-cylindrical collars 10 and 12, joined by the thin, narrow 
flexible strap 18, are opened out to the position illustrated in FIG. 6. A 
flexible corrugated conduit 8 having alternating ribs and troughs in the 
external surface thereof is then placed against one of the 
semi-cylindrical collars 10 or 12 so that the radially inwardly projecting 
rib 15 on that collar engages one of the troughs or grooves in the 
external surface of the conduit. The end face of the conduit 8 then bears 
against the arcuate stop flanges 19. The other of the two semi-cylindrical 
collars 10 and 12 is then folded to a closed position as illustrated in 
FIG. 3, so that its radially inwardly projecting rib 15 also passes into 
and engages the groove or trough formed in the external surface of the 
corrugated conduit 8. 
With the flexible corrugated conduit positioned between the 
semi-cylindrical collars 10 and 12 in the manner described, the terminator 
fitting 4 is pressed through the opening in the side wall of the box 6 by 
initially inserting the inner end of the fitting (the end having a 
radially smaller diameter) into the opening through the box, and forcing 
the arcuate box-engaging projections 20-26 into the box until they snap 
engage the box where it surrounds the opening 7 therethrough. Stated 
differently, the terminator fitting 4 is forced inwardly through the 
opening in the box 6 until the edge of the box wall around the opening 7 
comes to rest within, and to occupy, the groove or recess segments defined 
by the several wedge-shaped end portions 20a-26a of the projections 20-26, 
the web portions 32 and the two semi-cylindrical collars 10 and 12. As the 
terminator fitting 4 is being pressed into its interlocked operative 
position, the several box-engaging projections 20-26 can be flexed 
radially inwardly, as has been previously described, with the several 
blocking flanges 20b-26b clearing the adjacent projections, and avoiding 
any sort of interference or contact with these projections which would 
preclude the box-engaging projections 20-26 from undergoing the necessary 
inward flexure to permit the terminator to be snap engaged with the box 6. 
In installations where the grooves and ribs around the exterior of the 
conduit 8 are of a helical or spiral shape, and mate with identically 
configured ribs 15 provided on the terminator fitting 4, the corrugated 
conduit 8 can be further screwed into the fitting toward the interior of 
the flexible outlet box toward the blocking flanges 20b-26b. These flanges 
are positioned radially inwardly with respect to the remaining radially 
inner surfaces carried on the wedge-shaped free end portions 20a-26a of 
the arcuate box-engaging projections 20-26. The conduit 8 will then 
ultimately be forced against the several blocking flanges 20b-26b, and 
will, by such contact, tend to force the box-engaging projections 20-26 
radially outwardly slightly so as to more firmly grip the wall of the box 
6 between the collars 10 and 12 and the radially thickest portion of the 
wedge-shaped free end portions 20a-26a end portions. This will firmly lock 
the terminator fitting in position within the opening in the box, and will 
also tend to prevent further inward or outward movement of the corrugated 
conduit. 
From the foregoing description of the invention, it will be perceived that 
the present invention provides an improved terminator fitting for use in 
connecting a flexible corrugated conduit or pipe to an electrical outlet 
box. The use of the blocking flanges located in the positions described 
affords a reliable safeguard against electrical conductors becoming jammed 
into the space between adjacent box-engaging projections forming a part of 
the fitting, and assures that the fittings will have a longer and more 
trouble-free operating life. 
Although a preferred embodiment of the invention has been herein described 
in order to illustrate the basic principles which underlie the invention, 
various changes and innovations can be made in the illustrated and 
described structure without departure from these basic principles. All 
such changes and innovations are therefore deemed to be circumscribed by 
the spirit and scope of the invention, except as the same may be 
necessarily limited by the appended claims or reasonable equivalents 
thereof.