An overhead ceiling structure with an integrated fixture hanging assembly, the fixture hanging assembly being supported by a yoke means bridging a pair of adjacent ceiling frame rail members.

CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. Ser. No. 4≡,575, filed Mar. 28, 1974 now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to supports employed primarily in overhead structures such as suspended ceilings in the integration of ancillary lighting, ventilation, smoke detection, speakers, signs, alarms, auxiliary lighting and like equipment into the ceiling. 
     Under current construction procedures, an interior ceiling of substantial area may be connected to an overhead roof or roof superstructure, the interior ceiling being generally known as a "suspended" ceiling. In such a ceiling, it has been found necessary and/or desirable to incorporate lighting or ventilating or like systems of various types, including upwardly spaced or coved lighting or ventilating means. 
     It is a basic objective of the present invention to supply improved supporting means for the incorporation of the illumination or ventilation means into a ceiling, the supports being of a construction and assembly such that the system is fully compatible with available structural materials for the construction of suspended ceilings. The fixture housings contain apparatus such as lighting equipment which is retained in such manner that bulbs and other portions requiring maintenance or replacement are readily accessible from below. 
     The invention has primary relation to these gridtypes of suspended ceilings presently in vogue in modern public buildings, shopping centers, apartments and the like and is directed to means for facilitating the installation of a junction box or lighting fixtures, smoke detector, etc., capable of supporting such as a lighting fixture or device, or other article, which fixture or device or article frequently is of considerable weight. Typically up to about 30 lbs. can be supported by a single hanger strap before center deflection. 
     The insertable and removable ceiling panel is hardly dependable for supporting a heavy fixture or device or article, same being commonly a flush mounted or recessed type of fixture located at any desired position in a selected ceiling panel. The choice and type of fixture or device or article available for use with a suspended ceiling is normally limited accordingly. 
     SUMMARY OF THE INVENTION 
     Therefore, one particular object of this invention is to allow the adoption and use of an unlimited choice of fixtures or devices or articles with respect to shape, size or design in a range from simple low-priced to expensive highpriced types and with a minimum of concern as to weight. 
     A further object resides in the provisions of supports of standard modular dimension having new and novel bracket means whereby the supports and appurtenant apparatus are readily substituted for existing modules. 
     Yet another object is to provide a support for such a fixture as aforesaid wherein the fixture is easily maintained, is readily accessible from the underside for cleaning, repair or replacement of components, and may be used either with or without shields, diffusers, or other accessories. 
     An additional object of importance pertains to the construction and assembly of supports of this type from standard stock, with the result that the supports are noncomplex in construction and assembly, inexpensive in manufacture, and durable in use. 
     Still another object of the present invention relates to providing a preferred supporting means which is safer, especially from the standpoint of electrical isolation, than supporting means provided heretofore. A further object is to provide such means adapted to be anchored to the ceiling above the T-bar network. 
     A still further object of this invention is to provide a supporting means which is selectively adjustable in height. 
     The concept of providing means in a suspended ceiling framework to offer adequate support means for fixtures or devices or articles is hardly new, but this invention, structurally, functionally and otherwise, improves upon known prior art support means, involves features which are new and novel, and provides a suspension unit which is an advancement over the art. 
     The concept relates to a prefabricated adaptor unit which includes a single, rigid, straight hanger strap in the form of a supporting bar of a predetermined length proportional to the space anticipated to be bridged, which hanger strap serves to accommodate a slotted fixture stud for the threaded engagement with and support of a conventional type junction box. For the purposes of supporting devices other than conventional junction boxes, such as recessed fixtures, audio speakers, smoke detectors, and the like, the hanger strap serves to accommodate U-shaped mounting brackets in lieu of a threaded fixture stud. The respective end portions of the hanger strap are provided with clips or mounts, each consisting of a horizontal part associated with an end portion of the hanger strap and integral with a right-angularly-disposed downwardly-opening generally T-shaped terminal end part defining a strap mounting and attaching means, which means is slip-fitted over opposite sides of the vertical flange of the T-iron employed in the ceiling frame. 
     In other words, the hanger strap is of a requisite length and straight from end to end and serves to accommodate the conventional junction box, or other fixture, such as a recessed fixture, a speaker, smoke detectors, exit signs, etc., the support means being either in the form of a fixture stud which is slotted so as to be slidingly received over and along the hanger strap in a manner to permit the junction box to be shifted so as to assume and maintain any selected situs relative to the ceiling and of course relative to the room, or other means, such as a U-shaped mounting bracket adapted to be clipped on the hanger strap and further adapted to be fastened by a screw to the appropriate fixture or other device. A straight hanger strap, in contrast to the prior art U-shaped strap, gives versatility with most types of recessed fixtures. 
    
    
     Other and further objects and advantages will become apparent to those skilled in the art from a consideration of the following specification when read in conjunction with the annexed drawings in which: 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top plan view of a portion of suspended ceiling construction with a first form of support yoke of the instant invention in use therewith; 
     FIG. 1A is a perspective view showing a hanger strap with free distal ends and having clipped thereon a mounting bracket used in connection with this invention; 
     FIG. 1B is a side view of the mounting bracket shown in FIG. 1A and a side view of a sheet metal screw used in connection therewith; 
     FIG. 2 is an enlarged transverse sectional view of the FIG. 1 showing with certain parts broken away or in section for clarity; 
     FIG. 3 is an enlarged side elevational view of the first form of clip or mount of the invention; 
     FIG. 4 is a front elevational view of the FIG. 3 clip or mount; 
     FIG. 5 is an exploded view of the conventional fixture stud used in connection with the invention; 
     FIG. 6 is an assembled view of the FIG. 5 fixture stud; 
     FIG. 7 is a side elevational view of a preferred form of the clip or mount of the invention; 
     FIG. 8 is a front elevational view of the FIG. 7 clip or mount; 
     FIG. 9 is a rear elevational view of the FIG. 9 clip or mount; 
     FIG. 10 is a side elevational view of an especially preferred form of the clip or mount of the invention; 
     FIG. 11 is a front elevational view of the FIG. 10 clip or mount; and 
     FIG. 12 is a rear elevational view of the FIG. 10 clip or mount. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Proceeding to a more detailed description of the invention and referring initially to the form shown in FIGS. 1-4, the support assembly and ceiling construction hereof includes at least one pair of spaced apart parallel coplanar longitudinal rail members 10 and 12 and a transverse rail member 14. The rail members are of inverted T shape and have upstanding legs 15 with a bead 16 and distal and proximal ledges 17 and 18. The rail members are suspended in a grid arrangement from some overhead anchorage such as a roof or roof beams (not shown) by such as hanger cables or the like engaged in provided openings through the leg below the bead. 
     Horizontally arranged blocks C of interior ceiling material, such as acoustical tile or the like, are suspended on the ledges 17 and 18 of the rail members. The blocks C thus form an interior ceiling disposed in a given substantially horizontal plane. 
     So much as has been above described comprises known standard equipment. Accordingly, the supporting assembly hereof is readily employed in existing structures. 
     The usual outlet box J is adapted to be supported from hanger strap 20 by a fixture stud in the following manner: 
     A plug S includes a slot 32 to define an upper or top wall 30 which rides on top of the hanger strap as the hanger strap is extended through the slot 32 and a lower or bottom wall 34 which has a threaded aperture 36 centrally therethrough. 
     The hanger strap is adjustably extended relative to the fixture stud as is clearly evident in FIGS. 1 and 2. That is, the hanger strap serves to accommodatingly and adjustably support the fixture stud and its associated junction box J. 
     The fixture stud also includes a retaining yoke Y which includes an upwardly projecting tongue 40 unitary with a lowermost externally threaded bulbous portion 42 having a through opening 44 extending therethrough. 
     A set screw 46 extendable through aperture 44 is threadedly engageable with the thread in aperture 36 so as to bring the topmost planar surface of retaining yoke 40 into snug embracement with the underside of the hanger or strap as shown in FIG. 6 so as to make a tight hanger strapfixture stud relationship. 
     The fixture hanging junction box is threadedly mounted on the threaded end of annular portion 42 and is accordingly held against rotary movement. 
     The junction box can be easily slid freely along the length of the hanger strap and can be secured by tightening set screw 46 at any selected position. This feature provides adjustability in the placing and centering of the fixture box. A hold is then made on the ceiling panel directly below where the box is secured and the fixture (not shown) is eventually hung therefrom. 
     FIGS. 1A and 1B represent an alternative mode to support a device from hanger strap 20 by use of a U-shaped mounting bracket 104 which is adapted to be snugly clipped onto the hanger strap 20. The mounting bracket 98 is adapted to receive a screw 99, such as a sheet metal screw, through aperture 100, to be further received by the open threaded portion of the appropriate fixture or device to be supported. In the practice of the present invention one or more of these mounting brackets 104 are contemplated. 
     The hanging fixture cannot be pushed upwards or out of place because the junction box is secured on the hanger strap which in turn is secured at both ends to the T-irons by means to be disclosed. Thus, the fixture is virtually immovable despite the fact that the ceiling panels can be pushed out of place in the usual manner by as little effort as a touch of the finger. 
     A plurality of yoke assemblies or adapter units is provided for extending between in bridging manner selected pairs of longitudinal rails 10 and 12 for the mounting of the upwardly spaced equipment. 
     The respective end portions are each provided with a substantially L-shaped clip or mount which includes a horizontally-extending component 21 which may be swagged or welded to the hanger strap so as to provide a strong rigid connection therebetween. 
     Such is the first or FIGS. 1-4 exemplification. 
     The second, or FIGS. 7-9, exemplification will be explained hereinafter. 
     In either instance, the connection will be seen to offer excellent resistance to bending, shear and torsional stresses resulting from the weight of such as a junction or outlet box supported by the hanger strap and also has good resistance to tension stresses tending to longitudinally separate the hanger strap and clips or mounts. 
     Additional to the horizontally-extending component 21, the clip or mount envisions a unitary vertically-depending component which branches from a main web portion 22 into a trio of spaced flexible legs 23, 24 and 25, the legs 23 and 25 representing outer relatively short legs capable of being flexed into a position over the bead 16 and against the inboard face of an upstanding leg 15 of a rail member wherefore the bottom edges of the legs may be spaced above the proximal ledge 18 so as to provide space for the ceiling blocks C, and the leg 24 representing an inner or intermediate relatively long leg capable of being flexed into a position over the head 16 and against the outboard face of the leg 15 of the rail member wherefore a pair of oppositely facing feet 26 may be brought to bear against the distal ledge 17 of the rail member so as properly to locate the hanger strap relative to the stud or joist involved. If the clip or mount is made of metal, obviously, an insulating coating can be applied thereto to provide protection against accidental passage of electric current to the T-bar network. Alternatively, at least the distal ends of the strap can also be insulated with a plastic coating or a plastic bushing. 
     In FIGS. 7-9 which are exemplifications of a preferred form of clip or mount, it will be understood that same will preferentially be formed of a flame resistant plastic material and will be of one piece. 
     A horizontally-extending component 80 will be observed to be of a thickness and width as to allow formation therein of an open-ended pocket 81 capable of receiving the free end of a hanger or strap. The pocket walls are configured with a slight taper inwardly so as to allow a snug friction fit when the clip is introduced to and is fitted upon the end of the hanger strap. 
     Depending downwardly from the base of the horizontal component 80, at one end thereof, is a unitary vertically-depending component which branches from a main web portion 82 into a trio of spaced flexible legs 83, 84 and 85, the legs 83 and 85 representing outer relatively short legs capable of being flexed into a position over the bead 16 and against the inboard face of an upstanding leg 15 of a rail member wherefore the bottom edges of the legs may be spaced above the proximal ledge 18 so as to provide space for the ceiling blocks C, and the leg 84 representing an inner or intermediate relatively long leg capable of being flexed into a position over the bead 16 and against the outboard face of the leg 15 of the rail member wherefore the bottom edge of the leg may be brought to rest upon the distal ledge 17. 
     In FIGS. 10-12 which are preferred embodiments of a modified and improved form of clip or mount within the scope of this invention, it will also be understood that the same will preferentially be formed of a plastic material, most preferably a flame-resistant plastic material, and will be of one piece. Particularly preferred include polyacetals, such as Delrin, available from duPont, and Celcon, available from the Celanese Corp. Most especially preferred materials are plastics having what is known as a plastic memory, i.e., one that always returns to its originally molded shape. 
     A horizontally-extending component 90 will be observed to be of a thickness and width as to allow formation therein of at least one, and preferably, a plurality of open-ended pockets 91 (two pockets are shown for exemplary purposes), each capable of receiving the free distal end of a hanger strap. To insure a snug friction fit with the end of the hanger strap, and to accommodate possible slight variations in the thickness of the hanger strap, the open-ended pockets 91 can be provided with ribs 98 extending lengthwise in the pocket. By virtue of providing a plurality of open-ended pockets 91, the supporting means of this invention is accordingly selectively adjustable in height providing the user thereof with a choice of heights to use in order to suitably accommodate the particular fixture with which he is working. For example, by inserting the free ends of the hanger strap in the lower of the open-ended pockets of the clips or mounts, the fixture will hang lower than if the free ends of the hanger strap are inserted in the higher open-ended pockets. Similarly, if the free ends of the hanger strap are inserted in the higher of the open-ended pockets, the fixture will hang higher. 
     Depending downwardly from the horizontal component 90, at one end thereof, are a trio of spaced flexible legs 93, 94 and 95. The outer legs 93 and 95 and the inner leg 94 are, in this embodiment, preferably all of a length permitting them to terminate at the same distance below the top of the T-bar. However, it is also contemplated by this invention to provide that outer legs 93 and 95 are shorter than inner leg 94, similarly to the construction shown in analogous FIGS. 7-9. In either case, the outer legs 93 and 95 are capable of being flexed into a position over the bead 16 and against the inboard face of an upstanding leg 15 of a T-bar rail member whereby the bottom edges of the legs may be brought to rest upon or at any strategic location above the proximal ledge 18 and the leg 94 representing the inner leg is capable of being flexed into a position over the bead 16 and against the outboard face of the leg 15 of the rail member whereby the bottom edge of the leg may be brought to rest upon the distal ledge 17. 
     As is further shown in FIGS. 10-12, each of legs 93, 94 and 95 terminate at its bottom end in tapered portions 101, 102 and 103, respectively. These are adapted to facilitate easy installation of the clip. In contrast to the earlier embodiments which do not have such tapered portions, merely forcing the clip into engagement with the top of the T-bar provides cooperation with each said tapered portion to automatically urge the legs apart and into proper engaging alignment. 
     In further preferred embodiments, horizontally extending components 80 and 90 can also be provided with at least one aperture, e.g., 96 or 97 in FIGS. 10-12. This provides a means for further supporting the ends of the hanger strap by engaging the free end of a tie wire or the like to the clip or mount and anchoring the other end of the tie wire to the ceiling. 
     In addition to their other advantages, the clips or mounts of the present invention made of plastic, provide safeguards against shorted fixtures and accidentally energized metal frameworks as a result of the electrically insulating properties of the plastic. Obviously, electrically insulating materials other than plastic are also contemplated herein for this purpose. 
     While we have illustrated and described a preferred and modified form of construction for carrying our invention into effect, the same are capable of variation and modification, without departing from the spirit of the invention. We, therefore, do not wish to be limited to the precise details of construction set forth but desire to avail ourselves of such variations and modifications as come within the scope of the appended claims.