US 2945661 A
Description (OCR text may contain errors)
WASH- July 19, 1960 lflu. l. APPLl-:ToN 2,945,661
TEILESCOPING BAR HANGER ASSEMBLY Filed July l1, 1956 TELEscorlNG BAR HANGER ASSEMBLY Arthur I. Appleton, Northbrook, Ill.` Appleton Elec- The present invention relates `to supporting devices amsn Patented July 19, 1960 tion is there shown embodied in an illustrative bar hanger 4for electrical boxes and nxtures used' in power supply Y;
vide a bar hanger assembly to be nailed between spaced oor joists or the4 like, and which is adjustable in length for facilitating insallation between joists spaced diierent distances apart.
Another object is to provide a bar hanger assembly of great strength, yet obtained with relatively thin gauge and light weight channel members telescoped together.
It is a further object to provide an interlock toprevent the telescoped members from pulling apart resulting in `collapse of the bar hanger, when nailed in place between spaced iloor joists or the like, the hanger is subjected to bending stresses of such severe magnitude as to bend the channel members.
A further object isA to provide a fixture mounting arranged to be slidable the length of the assembled box hanger, the mounting serving the dual purpose of securing an outlet box or the like to the bar hanger and also anchoring the outlet box against movement in any one of an infinite number of positions along the bar hanger.
Other objects will become apparent as the following V*description proceeds taken together with the accompanying drawingswheren: l
l Figure 1 is a perspective View of the telescoping bar hanger assembly embodying the invention; Fig. 2 is a side elevation of the telescoping bar hanger installed between laterally spaced iloor joists;
. nFig. 3jis an enlarged cross-sectional view taken along lines 3-3 of Fig. 2, through the xture stud and retaining lock nut securing the outlet boxto the bar hanger;
Fig. 4 isV an enlarged cross-sectional view taken through the telescoped channel. members,.in the plane y, of lines 4-4 of Fig. 2; i
Fig. 5 is an enlarged fragmentary view of the ends of the channel members interlocked, with part of the Y,
outer member broken struction; and
Figs. 6 and 7 are views illustrating the ordinarily concealed end of the inside channel member.
away to show the toothed con- While the invention is susceptible -of various modiiicainvention to the form disclosed, on the contrary,`the
intention is to cover all modifications, alternative constructions and equivalents falling within the spirit and scope of theV invention as expressed in the appended claims.
i Referring more specifically -to the drawings, the invenassembly designated with the general reference character 10, shown in Figure 2 fastened between opposed faces 11 of a pair of laterally spaced supports. in the form of oor joists 12.- Rgidly xed to the bar hanger assembly is an outlet box 13, the assembly being so lo cated relative to the edges of the joists thatthe lower edge of the outlet box lies substantially coplanar with the lower edges of the joists. Y t. In the present instance, the telescoping bar hanger assembly comprises a pair of telescoped `channel -mer'n'- bers 15, 16' respectively, generally tubular in shape, here shown as having an arched cross-section, and freely slidable one within the other for varying the overall length of the bar hanger in order to enable the bar hanger to be installed between joists spaced different distances apart. f t Y -f Forv fastening the free vends of the telescoped members 15, 16 to the joists, the thin gauge sheet material from which the channel members are formed,y isv flattened for a limited longitudinal extent, and bent at right angles to the channel members to present relatively wide anges 17, 18 which may be fastened to the joists by means of nails hammered lthrough* openings-19, V2l) punched through the material of the flanges. By leaving sharp lanced or struck-out deformations Z1, 22 providing outwardly extending teeth, as shown in Fig. 2, around the nail holes, nailing the -bar hanger in place Vbetween the joists is facilitated. When the bar hanger is held With the flanges 17, 18 against the Yjoists, a hammer blow against the inner surface of the flange will drive the llances into the joists to temporarily hold'the bar hanger in place while the nails are driven. f
In `the illustrative form of the invention illustrated 'in Figs. l and 2, the outlet box 13 is securedito the bar hanger by a combined outlet box connector'and anchor. In this instance, the outlet box is supported from the hanger so as to be movable along the longitudinal'extent of the assembled channel members, and by means of the combined outlet box connector and anchon'the outlet box may be fixed at any given point depending upon the spacing desired from the floor joists between which the hanger is suspended. As illustrated, each channel member 15, 16 is -formed from thin gauge sheet material such as aluminum or sheet steel, bent up to a substantially arched shape but leaving a relatively narrow slot longitudinally of the under side of 4the members. The formed channels each include the curved back'wall and a bottom wall,-where preferablythe narrow slot is left. The channel members 15, 16 are sized for a sliding tit one within the other, and when/telescopedl together are arranged so that the under side slots are alined and provide al continuous, uninterrupted slideway, in the-present instance, the full length ofthe assembled bar hanger assembly. By employing generally tubular or' channel members in the bar hanger assembly, a relatively thin section suffices to provide optimum strength and rigidity, while affording an extremely lightweight assembly.
To secure the outlet box 13 to the bar hanger assembly, a headed fixture stud 25 is employed (Figs. 1-5), inserted to slide within the slideway provided by the alined slots in the under side of the channel members. f In the present instance, the stud 25 is made with a head portion 26 formed to slide easily within the inside channel member. For convenience, and to prevent cocking of the' headed portion it is elongated in length, and in section slightly 'undersize with respect to the inside dimension ofthe channel member in whichV it is received. r[illus the head of the stud 25 is captivev against rot-ation inside the channel members. j l., 'That'portionof the stud 25 which receives. the-outlet box may be termed the body 29, and it projects a short distance below the bottom of the channel member being threaded to receive a retaining lock nut 30. As shown in Fig. 2, the xture stud projects through a knock-out opening 311m the `bottom w'all 32 of the utletor junctionbox 13. yThe body part'29 of the stud necks down as it merges into the head to tit between the edges of the slot in the under sides of the channel members, the clearance being 'such as allows free movement of the stud lengthwise of ithe members.V vIn order to hold the outlet or junction box 13 in place on the stud 25, a retaining or lock nut 30 may be used. The nut 30 here takes the form of a relatively short sleeve, both internally and externally threaded, the internal threads 36 adapting the nut to engage Ithe threaded body part 29 of the iixture stud 25 to secure these/two elements together. Projecting radially from the body of the retaining nut 30 is a radial flange 37 having a thickness substantially less than the axial dimension of the annular body 29 of the retaining nut. The radial Yange 37 in the present instance has dened therein a plurality of notches 38, in this case three in number. These notches provide for tightening or loosening of the retaining nut by the application of force from a driveable handtool such asa screwdriver, or by means of a wrench.
In fastening the outlet box to the bar hanger assembly, the retaining nut 30 is tightened on the threaded fixture stud, themarginal portion of the box wall 40 surrounding the opening being squeezed between the radial ange of the retaining nut, on the one hand, and the underside of the channel members, on the other hand. This squeezing action, of course, clamps the box securely in place between the annular retaining nut and the underside of the channel members. It will also be observed that the .retaining nut can be threaded up tight against the underside of the channels, permitting securely fastening outlet or junction boxes of the thinnest wall section while still enabling fastening in place outlet or junction boxes having thick wall sections.
In addition to fastening the outlet box to the bar hanger, the fixture stud and retaining nut also serve to tix the outlet box at any desired point along the bar hanger, hence, the ascribing of a dual function -to the xture stud and retaining nut. That is, theretaining nut by clamping the elements together, serves to anchor the outlet or junction box to the bar hanger. Frictional engagement prevents the elements from moving when the retaining nut is tightened, while allowing the outlet or junction box to be easily adjusted along the bar hanger when the retaining nut is loose.
When -the Youtlet or junction box is mounted on a section of the bar hanger where the channel members 15, 16 overlap, the retaining nut clamps the channel members together, yas well as clamping the outlet box to the bar hanger itself. Since this bar hanger is used in power supply systems of buildings and other structures, it must be approved -by the Underwriters Laboratories. One of the tests to which the bar hanger is subjected is commonly termed the dead weight test, where a heavy weight is suspended from the fixture stud or outlet box. With the outlet box fastened on a section of the lbar hanger where the channel members overlap, the resistance to bending is very substantial. This is the result of having a double wa'll thickness of material, having the channel shape ofthe telescoping members which imparts rigidity to the assembly, and in addition having the clamping arrangement which resists bending of the members and slipping of one relative to the other.
On vthe other hand, when the outlet or junction box is mounted along a section of the bar hanger (left hand position Fig. 2) where the channel members do not overlap,rthat is, on only one of the telescoping members of the assembly, the resistance to bending is naturally less. Furthermore, the advantage is lost of the clamping -etect aiordedfby the retaining nut to prevent Vendwise Slipping of the members. Suspending a very heavy dead weight from a box so mounted may cause the single channel member supporting the weight to bend, the result of this being the overlapping sections of the channel members slip relative to each other. If this slipping is not interrupted, the inner telescope member may pull entirely out of the other channel member resulting in collapse of the bar hanger. However, it should be noted that the hanger members Imay be bent by a heavy weight and caused to slip apart even when the box is fastened on a section of the hanger where the channel members overlap, if the box retaining nut becomes loose due to vibration or the like. In thiscase, too, if some means is not provided to prevent it, one member may pull entirely out of the other.
In the illustrative form of the invention shown in the drawings, means are provided for preventing the members from completely separating under such bending stresses. In the form of the invention shown in Figs. l-S, the interlock is eifected -by the inter-engagement of a tooth element on one of the channel members and a stop element on the other of the members. For -this purpose these elements are located adjacent the overlapping ends of the channel members.
The arrangement shown as illustrative includes laterally spaced teeth of opposite hand carried by each member at the overlapping ends. In other words, each channel member is formed adjacent the overlapping ends with teeth projecting laterally from the sides of the channel members towards the longitudinal center line thereof. Upon relative slipping movement of the' channel members `accompanied by canting the result of the downward acting weight which produced the bending stresses impressed, as illustrated in Fig. 5, just before the members would otherwise pull completely apart the teeth of one of said members engages what is effectively a stop or abutment presented by the teeth projecting laterally from the sides of the other channel member. This effectively prevents further separation of the hanger members. For convenience in manufacture, the teeth may be formed by cutting away a limited longitudinal extent of the bottom wall of the channel members, this extent being equal to the spacing of the cutout portion from the end of the member, leaving left and right hand teeth carried by both members adjacent the overlapping ends; although it will be understood this may be varied as desired.
The aforementioned canting or cooking of the telescoped members occurring as an incident to one of the channel members pulling out of the other has the result that the teeth on the inner channel member drops (in a sense) into the cutout portion of the'outside channel member. The pairs of teeth on both members then are in engagement and prevent further separating movement. Although the side walls of the channel members in the region of these cutout portions could also be cut away, tests demonstrate the eicacy of the present arrangement in producing the interlock desired. This canting is illustrated in Figure 5.
In the illustrative form of the invention shown in the drawings, the undersides of the inner and outer channel ymembers 15, 16, are cut away adjacent lthe ends to leave oppositely facing teeth 41, 42 and 43, 44 on the respective members. These teeth inter-engage as shown in Fig. 5, to obtain the interlock desired to prevent separation of the members.
The length of the individual telescoped mem-bers is selected to provide a hanger which will be usable in ordinary building structures where the iioor joist spacing and wall stud spacing varies only a few inches in keeping with upto-date practices as set by local building ordinances, and as required to conform to Federal Agency regulations. lt is preferred that bar hangers of this type be made in different sizes, so that the Iwork-men can select a size appropriate for a given installation. The 4proper' hanger size, ordinarily, for a given joist spacing is provided vee when the desired over all length of the hanger occurs with a moderate length of overlap of the members, as shown in Fig. 2. The longest length is that provided by separating the members to a point just prior to registration of se ieth and cut-out portions (which is illustrated in To facilitate obtaining the shortest over all length, the inner telescoped member is notched at the end 4S to conform to the inside Wall 46 at the corner o-r bend made in forming the tianged end 18 of the outer member V16 and which constitutes the mounting ilange. With this arrangement the inner member is allowed to butt up sol-idly against the mounting flange, Fig. 6 illustrating the inside member sliding towards this position.
I claim as my invention:
l. A bar hanger for supporting an outlet box or the like between a pair ot laterally spaced supports such as floor joists, said bar hanger comprising, in combination, a pair of generally tubular cross-section channel members telescoped together for varying-the over all length of the bar hanger and having relatively narrow uninterrupted alined slots extending longitudinally of the members along the undersides thereof, means for fastening the free ends of the members to the supports, means for securing an outlet box to the telescoped members, and means for preventing complete separation of the overlapping ends of the assembled members of thebar hanger when -thelatter -is erected and subject to bending stresses tending to pull said members apart, said last named means including laterally spaced teeth of opposite hand carried by each member adjacent the said overlapping ends, the teeth projecting laterally Ifrom the sides of the channel members towards the longitudinal center line thereof, so that said teeth inter-engage ras the said overlapping ends approach each other.
2. A bar hanger for supporting an outlet boxer the like between a .pair of laterallyk spaced supports such as floor joists, said bar hanger comprising, in combination, a pair of channel members telescoped together for varying the over all length of the bar hanger, means for fastening the free ends of the members to the supports, means for securing an outlet box to the members, and means fo-r preventing complete separation of the overlapping ends of the assembled members upon the telescoped members bending and slipping apart under bending stresses, said last named means being operative irrespective of the position of the outlet box longitudinally of the members and including a tooth element on one of said members and a stop element on the other of said members, said elements being located adjacent the overlapping ends of said members, the tooth element being arranged to engage thestop element when the members slip apart under such bending stresses.
3. A bar hanger for supporting an outlet box or the like between a pair of laterally spaced supports such as oor jois'ts, said bar hanger comprising, in combination, a pair of generally ltubular members slideably telescoped together for varying the overall length of the assembled members; means for securing the free ends of said mem-k bers to said spaced supports to erect the bar hanger; each member being formed from thin gauge sheet material bent up to an arched shape including a top and a bottom wall, and having a relatively narrow slot longitudinallyof the members in the bottom -fwalls thereof, the members when telescoped together being arranged so that the slots are uninterruptedly alined the combined length of the members; a headed txture stud inserted within the alined slots and adjustable longitudinally the full combined length of the members, the headed portion thereof being wider than the slots for overhanging inside the members and engaging the bottom wall material laterally of the slots; a box retaining nut threaded on the stud to the exterior of the telescoped members, said stud constituting a combined outlet box connector and anchor to x the outlet box at a given point longitudinally of the members; and an interlock elective between the overlapping ends of said assembled members of the bar 'hanger when the latter is erected and subject to bending stresses tending to pull-the members apart, said interlock including teeth of limited longitudinal extent projecting laterally from the sides of vsaid channel members toward the longitudinal center line thereof and formed by cutting away the bottom wall of each of said channel members for a longitudinal extent at least as great as the spacing of the cut away portion from the ends of said members, so that said teeth interengage as the overlapping ends approach each other to prevent complete separation of said members.
McKinley lan. 24, 1956