US2538088A - Conduit box - Google Patents

Description

Jan. 16, 1951 J, DESLOGE 2,538,088

CONDUIT BOX Filed Jan. 29, 1949 INVENTOR JOSEPH DESLOGE xii ATTORNEY Patented Jan. 16, 1951 UNITED STATES PATENT OFFICE CONDUIT BOX Joseph Desloge, Florissant, Mo., assignor to Killark Electric Manufacturing Company, St. Louis, Mo., a corporation of Missouri Application January 29, 1949, Serial No. 73,588

2 Claims. 1 1

This invention relates in general to certain new and useful improvements in conduit boxes and methods of making the same.

Heretofore it has been the practice to fabricate conduit boxes by conventional casting procedure, employing sand molds and sand cores. Obviously, the preparation of cores is both time-consuming and expensive and has been found to result in castings which contain rough spots and frequently must be rejected for that, as well as other reasons. It has furthermore been found in actual practice that conduit boxes of the conventional type have various undercut surfaces which collect dirt and moisture and needlessly add to the weight of metal in the boxes without contributing to the structural strength thereof.

It is, therefore, the primary object of the present invention to provide a conduit box uniquely de-- signed to eliminate substantially all of the undercut surfaces and areas encountered in conventional conduit boxes, thereby materially improving the functional characteristics of the box and, at the same time, reducing the cost thereof.

It is a further object of the present invention to provide a conduit box and method of making the same whereby light weight alloys may readily be employed and the use of expensive or complicated sand cores may be eliminated.

It is an additional object of the present invention to provide a conduit box uniquely so designed as to permit the use of retractable cores, thereby materially simplifying the manufacturing operations and providing a conduit box having improved structural characteristics.

Wth the above and other objects in View, my invention resides in the novel features of form, construction, arrangement, and combination of parts presently described and pointed out in the claims.

In the accompanying drawing- Figure 1 is a fragmentary top plan View of a conduit box constructed in accordance with and embodying the present invention;

Figures 2 and 3 are sectional views taken along lines 2-2 and 33, respectively, of Figure 1;

Figure 4 is a top plan view of a modified form of conduit box constructed in accordance with and embodying the present invention;

Figure 5 is a transverse sectional view taken along line 5-5 of Figure 4;

Figure 6 is a top plan view of a further modifled form of conduit box constructed in accord Figure 11 is a sectional view taken along line I IH of Figure 10.

Referring now in more detail and by reference characters to as drawing, which illustrates practical embodiments of the present invention, A designates a conduit boxcomprising a unitary cast open-topped shell-like housing 9 integrally including straight parallel side walls 2, 3, connected by outwardly curved end walls t and a transversely extending bottom wall 5, defining a cavity a for housing an electrical switch, receptacle 01' other similar device. Also formed integrally with and projecting outwardly on either side from the end walls 4 are axially aligned tubular conduit hubs 6, which open at their interior ends into the housing and are internally threaded as at 7 for receiving the threaded end of a length of conduit pipe (not shown).

It should be particularly noted, as may be seen by reference to Figures 2 and 3, that the interior faces of the side walls 2, 3, and end walls 4 are sloped inwardly and downwardly and joined to the bottom wall by a short radius, as at r, so as to provide the interior without overhanging ledges or back-drafts from which a permanent retract able core will draw readily. Finally, the side walls t are provided centrally of their outwardly presented or exposed faces with tapped holes a by which conventional cover plate retainer screws (not shown) may be suitably installed.

If desired, a modified form of conduit box A may be provided, which is substantially identical in all respects with the previously described conduit box A except that it is provided with arcuate end walls 4' having relieved areas symmetrically disposed on opposite sides of the tapped hole 8' in the formation of recesses 9 which extend downwardly in the direction of the bottom wall 5, terminating somewhat above the opening It from the tubular conduit hub 6-. The side walls of;

the recesses 9 have slight inward and downward angles of convergence very much in the same manner as previously described with respect to the walls 2, 3, 4, of the conduit box A, so that a retractable core may be used and will freely withdraw from the interior of the conduit box A. It has been found that, by the employment of the recesses 9 in the design of the conduit box A, it is possible to produce a conduit boX of somewhat lighter weight without sacrificing to any material degree the strength or efficiency thereof.

If desired, a further modified form of conduit box B may be provided comprising a rectangular box-like open-topped casting integrally including straight parallel side walls l i, [2, transversely connected by straight parallel end walls 13 and a transversely extending bottom wall 4, defining a cavity 1). Also cast integrally with, and extending around the peripheral edges of the walls I 6, l2, l3, is a continuous outwardly turned flange l which in relatively narrow along the walls I i, l2, and is relatively wide along the transversely extending end walls it. Also formed integrally with the end walls I3, and projecting outwardly from the outer faces thereof and downwardly from. the under face of the wide transversely extending portions of the flange 15, are integrally cast hubs it which are axially drilled, counterbored, and tapped to provide sockets I1 internall threaded for receiving conduit pipe or tubing (not shown). As will be noted by reference to Figures '2 and 8, the inside faces of the walls H, l2, l3, and the outer side faces of the hubs H5 are provided with slight angles of convergence or inward taper, as it may be called, to permit the use of retractable permanent cores which may be readily withdrawn therefrom and also to permit ready withdrawal of the entire casting B from the mold, so that, if desired, a permanent mold may also be used.

The hubs it are finally provided in their upper portions above the pipe sockets H with tapped holes M3 for receiving conventional cover plate attachment screws (not shown), and symmetrically arranged on either side of the tapped holes i3 are'downwardly and inwardly tapered recesses ii?" which open later lly into the cavity 1) and terminate in arcuate bottomed walls to concentric with and located in radially outwardly spaced relation to the pipe sockets l? for eliminating excess weight of metal and preventing the formation of cooling stresses which ordinarily occur in the heavy portions of castings of the type here under discussion. It will be noted in this connection that the recesses is are tapered very much in the same manner as the inner faces of the walls ii, E2, 52, so as to be capable of being formed by suitable projections which are a part of a single retractable core.

If, desired, a further modified form of conduit box C may be provided, comprising a somewhat circular box-like open topped casting having a substantially cylindrical annular side wall the interior face of which is tapered inwardly and downwardly toward a flat bottom wall 2!, defining a cavity 0. Formed integrally upon and projecting outwardly from diametrally outward position upon the exterior face of the side wall are mounting cars 22., which are substantially flush upon their under face with the under face of the bottom wall Also formed integrally with the side wall 29 at 90 intervals therearound are hubs 2-3 which are thicknened and provided with interior and exterior faces substantially perpendiculanto the bottom wall 25. The hubs'ZB- are furthermore drilled and tapped for receiving the threaded ends of either conduit pipe or conduit receiving fittings, as be desired.

Upon their under faces, each 23 extends upwardly in the provision of an integrally cast boss 24 which is drilled and tapped as at 2?: for conventionally receiving screws by which a receptacle or other electrical device may be secured in place. It should be particularly noted in this connection that all interior and exterior surfaces of the conduit box C are arranged to eliminate overhanging ledges or back-drafts so that a permanent retractable core may be simply and expedientiy used and entire design is thus readily adaptable to fabrication in a die casting machine or by sand casting methods by the use of permanent cores.

It has been found that conduit bones constructed. in accordance with and embodying the present invention unusualiy strong and durable and are of a design whic lends itsel readily to much more economical methods of fabrication than heretofore have been possible. in fact, the conduitboxes of the present invention are readily adaptable to mechanical mother of casting, such as die casting machines, for example.

a central cavity defined by a bottom portion and side walls and end walls, said side and end walls being sloped inwardly and downwardly toward the bottom portion in a converging manner and being joined to the bottom portion by a radius, the said end walls being made thicker than the side walls and at least one end wall being pro vided upon its outwardly presented face with an integrally cast projecting hub, said hub being counterbored to provide a conduit-receiving opening, each of said. thickened end Walls having a pair of downwardly and inwardly tapered recesses opening on its inner face, the bottom of the recesses on the said hub-bearing end wall being formed by arcuate walls located above the bottom portion of the conduit box and being substantially concentric with the conduit-receiving opening, the walls of said recesses defining projecting spaced pillars the end faces of which lie in the plane of the op n-top.

2; A substantially rectangular conduit box comprising a cast metal body having an open-top and a central cavity defined by a bottom portion and side walls and end walls, said side and end walls being sloped inwardly and downwardly toward the bottom portion in a converging manner and being joined to the bottom portion by a radius, the said end walls being made thicker than the side walls and at least one end wall being provided upon its outwardly presented face with an integrally cast projecting hub, said hub being counterbored to provide a conduit-receiving opening, each of said thickened end walls having a pair of downwardly and inwardly tapered recesses opening on its inner face, the bottom of the recesses on the said hub-bearing endwall being formed by arcuate walls located above the 76 bottomportion of the conduit box and being sub- 5 stantially concentric with the conduit-receiving opening, the walls of said recesses defining ro- J'ecting spaced pillars the upper end faces of which lie in the plane of the open-top, said upper end faces of the pillars being provided with internally threaded openings adapted for receiving fastening elements.

JOSEPH DESLOGE.

REFERENCES CITED UNITED STATES PATENTS Name Date Hinsdill Apr. 9, 1907 Number Number Number Name Date Raymond Dec. 1, 1908 Ward May 20, 1919 Boyton et al May 15, 1928 Shickluna Nov. 19, 1929 Mever Dec. 2, 1930 Steber Aug. 25, 1942 Popp Mar. 21, 1944 FOREIGN PATENTS Country Date Great Britain June 11, 1925 Great Britain Oct. 8, 1931

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