Multiple passage wiring duct

Nov. 6, 1934

1,979,804

G. A. LUTZ

MULTIPLE PASSAGE WIRING DUCT

Filed Feb. 16, 1932

<img file="US1979804A_D0001.tif" />

Patented Nov. 6, 1934

1,979,804

UNITED STATES PATENT OFFICE

1,979,804

MULTIPLE PASSAGE WIRING DUCT

George A. Lutz, Cranford, N. J., assignor to National Electric Products Corporation, New York, N. Y., a corporation of Delaware

Application February 16, 1932, Serial No. 593,256

Claims. (CI. 247—32)

This invention relates to improvements in ducts providing raceways for electrical wiring and more particularly to ducts which are intended to be buried in a floor, which are commonly known as underfloor ducts.

With present methods of electrical wiring it is the common and well established practice to provide separate ducts for circuits of different potential so that low potential circuits may be positively and definitely separated and. kept away from possible contact and possible short circuiting with high potential circuits. Such separate ducts are frequently installed side by side in parallel relationship and such separate ducts may be of the same size or may differ in size. Such ducts are also provided with outlets in the form of outlet necks which are provided at frequent intervals along the ducts. Often times and usually, more outlets are provided than are required and such unused outlets increase the cost of the ducts. Furthermore separate ducts as heretofore used must be individually installed in the floor and individually fitted in boxes and fittings.

One object of the present invention resides in the provision of a single duct with one or more distinctly separated passages or raceways therein, with a common exterior wall for all of the various passages or raceways whereby the use of separate ducts to provide the separate passages may be obviated.

Another object of the present invention resides in the provision of a tubular multiple passage duct with dividing partition means therein to separate the duct into multiple passages.

Another object of the present invention resides in the provision of a multiple passage duct of a configuration which requires far less material than is required for separate ducts of equivalent size.

A further object of the present invention resides in the provision of a multiple passage duct which is adaptable for mounting in the floor and for securing in fittings and boxes in the same manner as a single passage duct. In this way the number of duct supporting means and. the number of entrances in junction boxes with their multiplicity of duct securing means may be materially reduced.

A further object of the present invention resides in the provision of a multiple passage duct with outlet means therefor which may be common to two passages in the multiple passage duct or individual to such passages.

Further and incidental objects of the present invention reside in the provision of a duct and duct system which is more compact as to width; which requires less space; which is required for the entrance of the duct into junction boxes, etc.; which eliminates the necessity of handling 60 extra ducts in the course of manufacturing and finishing and the cutting off and installing of multiple ducts upon the job and generally in the provision of a duct which is cheaper to manufacture and install than previous ducts. 65

Further and other objects of the present invention will be hereinafter set forth in the accompanying specification and claims and shown in the drawing which by way of illustration shows what I novz consider to be the preferred 70 embodiment of my invention.

In the drawing:

Figures 1, 2, 3 and 4 are end views of ducts incorporating features of the present invention. Fig. 1 shows a multiple passage duct with two 75 pairs of passages of the same size. Fig. 2 shows a three-passage duct with the different duct passages of the same size and Figs. 3 and 4 respectively show a two-passage duct with the passages of different size and a three-passage so duct in which two of the passages are larger in size than the third passage;

Fig. 5 is a cross-sectional view of a twopassage duct, the section being taken substantially along the line 5—5 of Fig. 6; §5

Fig. 6 is a top plan view of the duct shown in Fig. 5;

_Fig. 7 is a sectional view of a different form of two-passage duct with distinctive outlets, one set of outlets being provided for each passage. 90 This section is taken substantially along the line 7—7 of Fig. 8;

Fig. 8 is a top plan view of the duct shown in Fig. 7;

Fig. 9 is a sectional view of a modified form 95 of duct of the general type shown in Fig. 5; and

Fig. 10 shows several views which delineate the manner of use of a multiple passage duct in a single entrance junction box which box is adaptable also for use to receive two separate 199 single passage ducts.

According to the present invention multiple passage ducts are constructed in tubular form from strip sheet metal with a single exterior wall portion 20, which exterior wall portion may 105 be provided with curved up portions defining inwardly facing opposed grooves 21 and 22 which receive a strip 23, such strip forming the common dividing wall between two separate passages 24 and 25 (see Fig. 1). By constructing jjq

1.979.804 the duet in this manner there is a material saving in duct material over that required for two separate single passage ducts, since in lieu of requiring four side wall portions for bounding 5 each single passage duct, making eight wall portions in all, only four· side wall portions and a dividing wall portion are required. This gives a saving of material substantially equivalent to that of one side wall portion of a single passage 10 single duct. The grooves 21 and 22 may be disposed centrally of the duct along the horizontal center line to provide equal sized passages such as are shown in Fig. 1, or the grooves may be disposed off the central line of the duct to pro15 vide unequal sized passages 24α and 25α. Also· in place of having a single pair- of grooves 21 and 22 such as are shown in Figs. 1 and 3 a multiplicity of pairs of such grooves may be provided (see 21α—22α, 21b—22b [Fig. 2]) adapted 5>0 to receive two dividing strips 23α and 23b. With such, an arrangement a three-passage duct is provided. Obviously any number of dividing strips can be used depending upon the number of passages which are desired. In Fig. 4 the 25 multiple grooves are designated 21c—22c and 21d—22d and these grooves are adapted to receive dividing strips marked 23c and 23d.

From the foregoing it will be understood that the location and numbers of grooves may be §0 varied according to the size and number of passages which are required in each duct. According to the embodiment shown in Fig. 2, three equal sized passages 24, 25 and 25b are provided and according to the embodiment shown in Fig. 35' 4, two equal sized passages 24—25 and one smaller sized passage 25c are provided.

Multiple passage ducts can conveniently be provided with integral outlet necks 26. Such necks it will be understood are disposed at inter40 vals along the necks. Such necks 26 can be provided disposed as shown in Figs. 5 and 6, that is directly over the dividing ’ wall. By disposing the outlet necks in this manner a single outlet will afford access to two passages. By disposing 45 the outlet necks in this manner a saving is made in outlet cost since a single outlet serves for both passages.

In place of having a common outlet for a pair of passages, individual outlets for the indi50 vidual passages can be provided as shown at 26α and 26b (Figs. 7 and 8). Such outlets are preferably disposed in staggered relation as shown.

In lieu of using the separate dividing strip 23 and the grooved portions 21 and 22 a multiple 55 passage duct with a pair of separate passages may be constructed from a single strip of metal in the manner shown in Fig. 9. Here the outer wall portion 20α has an extension 20b which forms the dividing wall for the duct. The por60 tion 20αα of the outer, wall preferably has its terminating end welded to the bent up portion 20b as indicated at 27.

Fig. 10 illustrates the manner in which a junction box 30, provided with a single entrance G§ opening or socket 31 is adapted to alternatively receive a multiple passage single duct 32 or two separate single passage ducts 32α and 32b. The socket 31 is provided with set screw passage means 34 which are adapted to hold either mul70 tiple single ducts 32α and 32b or the single multiple passage duct 32.

It will be appreciated that the use of ducts incorporating the principles of the present invention will afford numerous economies and 75 advantages. In place of manufacturing, hand ling and installing two or more separate single passage ducts, one multiple passage duct only need be manufactured, handled and installed. Less material is also required for a single multiple passage duct than for a multiplicity of 80 separate single passage ducts which afford multiple passages of equivalent size.

It will be understood that the ducts are provided with the multiplicity of outlets along a wall portion thereof and that such outlets with 85 any of the various forms of duct can be so located that each outlet affords access to a pair of distinctively separated passages in the duct or the outlets can be so located as to be individual to each duct passage. Furthermore, the 90 number and relative size of the multiple passages may vary according to the use to which the duct is to be put.

In all embodiments of the invention a common partition means is provided to distinctively 95 separate the tubular duct into separate passages. The use of such common sheet metal partition affords a saving of material and of cost over separate ducts because the material of one side wall portion is dispensed with. The ducts are 100 preferably made of steel strip shaped into tubular form and welded in any desired manner.