A New and Improved Conduit Terminal and Junction Box for Electric Wires.
Year: 1899

page_text: Date of Application, 3rd Oct., 1899-Accepted, 25th Nov., 1899
COMPLETE SPECIFICATION.
A New and Improved Conduit Terminal and Junction Box for
Electric Wires.
I, ROBERT MCKEAN THOMAS, of 141, Broadway, New York City, State of New
York, United States of America, Electrician, do hereby declare the nature of this
invention, and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:
This invention relates to terminal or junction boxes for conduits that contain
electric wires used in the distribution of electricity for lighting buildings and
other purposes. In modern practice, for the distribution of electricity used in
incandescent or are lighting of interiors of buildings, as well as for other purposes,
it is customary to incase the insulated wires which extend from a source of
electricity throughout the rooms of the building in tubular metal conduits which
are lined with insulating material, and at suitable points in the walls or floor
of each room an outlet cavity in the form of a box having a cover is provided
to facilitate the outward extension of the wires from the conduits that are merged
at the ends of the same in the walls of a junction or terminal box.
There may be one conduit for electric wires extended to a terminal box in
a room, or several conduits be projected thereto, and may enter the bottom wall
or one or more, side walls of said box at an arbitrary point, as the trend of the
conduit-pipes for wires is sometimes controlled by the plan of construction had
in walls of the building, so that the terminals of the conduits at the terminal
boxes vary in relative position, comparing one box with another.
It is very essential in the wiring of a building for electric lighting or other
electric service that such work be completed before the walls are coated with
plaster, as the difficulty of introducing terminal boxes for fixtures, switches, or
other necessary adjuncts to the lighting or signaling equipment is greatly
enhanced if such work is delayed until the walls and ceiling of rooms are coated
with plastering in the usual way.
Owing to the variation in position of inlet-apertures in the junction or terminal
boxes, as before explained, it has heretofore been the custom to place all the
conduits for electric wires before the walls are plastered, and then make a diagram
indicating the relative positions or terminals of the conduits that have to be
introduced in one or more walls of each terminal box. After the necessary data
has been obtained, the usual way is to order these special boxes from the manu-
facturer and await their construction and delivery to the contractor doing the
house wiring.
Frequently delays occur in furnishing the special terminal boxes, and the
plasterer proceeds with the work so that the party doing the house-wiring must
cut out cavities in the finished walls to permit of the introduction of the terminal
boxes, whereby in some cases injury to the walls unavoidably results, while the
work of placing said boxes is greatly retarded, on account of the wall cutting
that must be done to introduce the boxes at proper points in the walls and ceilings
of the rooms.
The object of this invention is to provide a peculiar and novel construction

page_text: for the terminal boxes that receive and support the ends of electric wire conduits
used in wiring buildings, which will afford convenient and reliable means for
the introduction of the ends of said conduits in a wall or walls of each box
without delay, or the necessity of providing a special individual box for each
location, whereby the boxes can be ordered in any required number previous
to the commencement of the work of wiring a building, and the entire wiring
and the terminal or junction boxes and other adjuncts that connect with said
boxes may be placed in position before the plastering of the building is
commenced.
A further object is to provide a novel construction for the terminal boxes which
will facilitate their introduction and the connection of the house-wire conduits
therewith when said boxes have to be placed in suitable excavations formed to
receive them in plastered or other finished walls of a building, after the latter
have been erected and completed prior to the introduction of electricity for
lighting or other purposes.
To the indicated ends, this invention consists in the novel construction and
combinations of parts, as is hereinafter described, and defined in the claims.
Reference is to be had to the accompanying drawings, forming a part of this
statement, in which similar characters of reference indicate corresponding parts
in all the figures.
Figure 1 is a plan view of the improvement in one of its forms of construction.
Fig. 2, is a plan view of a lower section of the improved terminal box shown
in Fig. 1, on the line of separation for both sections of said box. (Indicated
at 22 in Fig. 3.) Fig. 3 is a transverse sectional view substantially on the
line 33 in Fig. 1. Fig. 4 is a plan view of the lower section of a box of slightly
different construction. Fig. 5 is a plan view of the lower half-section of the
box, showing another slight modification in construction and the ends of wire-
supporting conduits connected therewith. Fig. 6 is a transverse sectional view
of the terminal box embedded in position in the side wall of a room, the line of
section being indicated at 88 in Fig. 5. Fig. 7 is an enlarged detached view
of a stopper-plate for apertures in one style of the terminal box, as indicated in
connection therewith in Fig. 4, and Fig. S is a transverse sectional view of the
stopper-plate on the line 12 12 in Fig. 7.
There are several novel features of construction embodied in this improved
terminal box, consisting, first in the formation of the box in two main parts
or sections that are joined together edgewise on a transverse plane. The section
of the box that is outermost in use is adapted to receive a cover and retain the
latter removably in place. The second feature of primary importance comprises
the provision of a plurality of partly or wholly completed openings in the sides
and bottom wall of the two-part box, the said partial or complete openings being
semicircular in outline in cach side wall of a box section, these semicircular
formations being opposite in pairs when the two main sections of the box are
joined, so that the joining together of the two parts of the box will afford a
plurality of circular-edged incipient or complete orifices in each side wall of
the box.
Another essential feature of the invention consists in the provision of guiding
projections at suitable points on one section of the box which will slide into the
other section when both sections are in contact at their meeting edges, whereby
these joined sections of the outlet-box are held from lateral displacement.
"
Another novel feature of the improved terminal box consist in the formation
of radial slots in the bottom wall of what may be termed the "lower half-section
of the box, which slots extend from a central opening therein and are adapted
to receive a headed screw or bolt for the secured connection of fixtures to the
bottom wall of the box, which may be introduced through an opening in the
lid of the upper box-section. The said slots are also available for the introduction
of screws through two or more of them into a stable portion of the building-wall
or floor of the same to secure the box in position.

page_text: Another important novel feature of the improvement consists in the peculiar
formation of the coupling-nut for each house-wire conduit, which nut is inter-
changeable to permit conduits of different diameters to have a coupled engage-
ment effected between a threaded end of the same and a complete aperture in
the side wall of two joined box-sections, the nut by its construction being adapted
for ready insertion or removal.
Referring to the drawings, it will be seen that the terminal boxes shown are
all rectangular in contour, and it here may be stated that while a box having
a rectangular form is preferable it is not imperative that the improved terminal
boxes be so shaped in outline.
As indicated in the brief description of the several figures of the drawings,
slight modifications in construction of the two part terminal box are shown, all
based on the broad feature of invention comprising the provision of incipient
or complete apertures in sufficient number in the sides and bottom of a box to
permit one or more end portions of wire-holding conduits to be held in engage-
ment with the box without regard to the point of approach to said box, had by
the conduit or conduits. These slightly different styles of construction will
now be described.
In Figs. 1 to 3, inclusive, are shown incipient orifices defined in the sides
and bottom wall of the two-part terminal-box, said orifices being each partly
produced by an indentation of semicircular form on the inner side wall of the
box, three such half-circular indentations a being formed in each side wall of
a section, which will afford a complete circular formation when the meeting
edges of the two box-sections 10 10" are in contact, as shown in Fig. 3. It will
be observed in this form of construction that the semicircular indentations « are
of a depth almost equal to the thickness of the side walls they are produced in,
and said indentations are covered by integral thin plates b, which join the
peripheral edges of the indentations, whereby the outer surfaces of the side walls
of the terminal box are rendered imperforate. Should it be desired to produce
a circular-edged orifice at a point coinciding with any of the incipient apertures
or indentations a, the thin plate covering b is broken, so as to remove each
semicircular portion of the same, which can be readily effected with a convenient
implement used by the workman who is placing the boxes in position, so that
an appropriate aperture may thus be produced with ease and celerity as occasion
may require, and it will be manifest that such portions of the box as are not
completely apertured in the manner specified will remain intact and thus prevent
the entrance of mortar or other detrimental material within the box when the
latter is in position. At each corner of the lower box section 10 a guide post C
is projected a short distance above the free edge of said portion of terminal box,
and these posts are adapted to fit in the corners of the upper box-section 10ª
when the two sections are fitted together, as shown in Fig. 3, and it will be evident
that the provision of the short posts C will retain the respective sides of the
joined box-sections in alinement and effectively prevent lateral displacement
of the same in any direction. There are four radial slots & formed in the bottom
of the box-section 10, which at their inner ends intersect the edge of a central
circular aperture e formed in the bottom of said box-section, and the lower wall
of the bottom is recessed along the edges of each slot for reception of bolt or
screw heads. The slots afford means for the convenient bolted attachment
of any desired fixture which is to project from the terminal box, and also may
be utilized for the insertion of the bodies of screws through said slots into
timbers or other stable portions of the buildings, walls, or floors, to retain the
box-section 10 in position. Other screw holes f may be provided in the bottom
wall of the box-section 10 for the reception of screws if such additional screw-
holes are desired.
The upper box-section 10 is preferably furnished with a circular flanged pro-
jection 10b, having two ears g projected inwardly from the outer edge of said
Hange, and a lid 10° is fitted on the circular portion of the box, projecting into

page_text: it a sufficient degree to permit the ears g to lock the lid in place after the ears
have passed through notches in the lid and the latter is rotatably moved. The
lid 10 may be imperforate if the box is placed in the floor, and when the box
is located in the wall or ceiling of a room the lid may be suitably apertured for
admission of a fixture of any style that is to be held projected from the wall
or ceiling.
In the bottom of the section 10 circular indentations a are formed, which
are covered by thin integral plates b, and any of the said circular recesses may
readily be converted into a complete orifice by removal of the covering b with
a convenient implement, so that a conduit for wires may be entered by its end
in an appropriate aperture in the bottom of the terminal box, which has been
readily produced, as required, by the workman who is wiring the building.
In Fig. 4, a rectangular two-part terminal box is shown which is substantially
similar in construction as the one already described, the only difference consisting
in the formation of the complete orifices h in the sides and bottom of the said
box-sections 11 and the covering of said orifices with a thin envelope 12 for
the semicircular or half orifices in each section 11 of the box. As shown, the
application of the envelope 12 seals the orifices on the outer sides of the box,
and as the said encircling closures are formed of material that may be easily
cut there may be an orifice completed at a suitable point in either side wall of
the box by use of a tool that will quickly remove the portion of the envelope
from over an appropriate orifice. The circular openings in the bottom walls
of the box-section 11 are completed in this style of construction for the terminal
box, and detachable cover-plates are provided, the preferred form of which is
clearly shown in Figs. 11 and 12, and it will be seen that these coverings each
consist of a disk having ears formed near its edge, which are adapted to bear
on the peripheral edge of the orifice in the bottom of box-section 11 and hold the
cover over said orifice, to be readily removed as occasion may require. In Figs. 5
and 6 another slightly modified method in the production of detachably-covered
orifices in the terminal-box is shown. In this construction there are indenta-
tions a formed in the sides and bottom wall of the two-part box in the same
manner as represented in Figs. 1, 2, and 3, the cover-plates in this case being
formed integral but flush with the outer sides of the box, the said thin coverings
being in a like manner removable when a complete orifice is to be produced in
a side wall or bottom of the box.
The two sections of the improved terminal-box are held secured together by
two screws K, that pass through perforations in the top section of the box and
screw into threaded perforations in the bottom of the lower section, the said
screws having heads that contact with the top wall of the upper section, and thus
adapt the screws to draw both sections of the box together. The interior of the
improved terminal box is rendered non-conductive of electricity, preferably by
coating it with enamel, but other means may be employed for said purposes.
The improved means for detachably securing an end of a conduit 1 in the
side of the two-part terminal-box consists in providing a nut 13, having a
circumferential groove m formed in it. The body of the nut where grooved is
circular and is of such a diameter externally as will permit it to fit in any completed
orifice in the side wall of the two-part box, and it will be seen that as the receiving
orifice is formed half in each box-section the nut 13, after it is screwed on the
end of the conduit, may be readily slid into place in the lower box-section, and
that the upper box section may then be placed in position, thereby clamping
the nut and retaining the end of the conduit connected with the terminal box,
as clearly indicated in Figs. 5 and 6.
This improvement in terminal-boxes for electric wiring will not only expedite
the work in new buildings, but will also facilitate the introduction of such
outlets in structures where the walls have been plastered, as the sectional division
of the improved box and novel means for connecting the ends of the wire-holding
conduits enables the ready introduction of the boxes in suitable recesses cut to

page_text: receive them in the plastered walls at proper points, and also permits the easy
and reliable connection of the ends of the conduits to be effented with the sides
or bottoms of the boxes.
Having now particularly described and ascertained the nature of this
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. A terminal or junction box for electric wires, the box having a series of
weakened portions which can be broken out to form openings, the weakened
portions serving to regulate the shape of the break, substantially as described in
the foregoing statement.
2. A terminal or junction box for electric wires, the box consisting of two
parts, each having an opening therein, the openings matching to form a single
opening when the parts are joined, a pipe passing through the said single opening,
and a nut screwed on the pipe, the nut having an annular groove receiving the
edges of the said single opening, substantially as described in the foregoing
statement.
3. A terminal or junction box for electric wires, the box having two sections,
cach of which is formed with a weakened portion, said weakened portions match-
ing with each other when the sections are joined and the weakened portions being
capable of being broken to form a single orifice, the form of which is regulated
by the form of the weakened portions, substantially as described in the foregoing
statement.
4. A. terminal or junction box for electric wires, consisting of two sections,
one of which is formed with two crossing slots, and the remaining section being
formed with a circular opening from which a flange outwardly projects, the flange
having an inwardly extending car, and a circular cover for the opening, the cover
engaging the flange and having an opening receiving the ear of the flange the
box having openings therein, through which the wires may pass, substantially
as described in the foregoing statement.
5. A terminal or junction box for electric wires the box being formed of
material, part of which has less strength than the remaining part, the thus
weakened part being capable of being broken separately from the remaining
part, and the weakened portion serving to regulate the form of the break, sub-
stantially as described in the foregoing statement.
1
LT
11
J
1000
ROBERT MCKEAN THOMAS.
By Herbert Haddan & Co.,
Agents to Applicant,
18, Buckingham Street, Strand, W.C., London.