Housing for electrical apparatus
United States Patent 1 1 Seabury, Jr.  
 [ Apr. 8, 1975 l l HOUSING FOR ELECTRICAL APPARATUS [75] Inventor: Richard W. Seabury, Jr., Towaco.  
 [73] Assignee: RFL Industries, lnc., Boonton NJ.  
 [22] Filed: Apr. 25, l974 2 l] Appl. No.1 464,043  
 [52] U.S. Cl. 220/4 R; 220/80 [5 l] Int. Cl 865d 7/32 [58] Field of Search 220/4 R. 4 F, 80, 62, 73,  
 [56] References Cited UNITED STATES PATENTS l.322,962 ll/l9l9 Sessions 220/4 F 2.371409 4/1945 Myes 220/4 R Primary ExaminerGeorge E. Lowrance Assistant E.\&#39;aminerSteven M. Pollard Attorney, Agent, or Firm-Rudolph J. Jurick [57] ABSTRACT A sheet metal housing having corners reinforced by self-retaining fasteners.  
 7 Claims, 16 Drawing Figures HOUSING FOR ELECTRICAL APPARATUS BACKGROUND OF THE INVENTION Housings for electrical apparatus generally are formed by bending a metal sheet into a desired configuration. In order to minimize weight, the housing prefer ably is formed of a relatively-thin sheet of aluminum. Also, a plurality of holes and slots are formed in the housing walls for purpose of ventilation and for receiving screws which fasten contained components and circuitry in place. In housings of this type, it is necessary to reinforce the corners thereof to produce a structure having the necessary rigidity to resist bending and twisting forces applied thereto. Presently, this is accomplished by welding the corner joints or by riveting gussets thereto. which operations are time consuming and expensive.  
  In accordance with this invention, the housing corners are preformed to accommodate simple, selfretaining fasteners which reinforce the corners and result in a rigid housing structure. The fasteners also serve as means for securing housings together in sideby-side relationship.  
 SUMMARY OF THE INVENTION Halfholes are punched in a sheet of aluminum at predetermined locations. The sheet is bent to form a generally-rectangular housing having side portions of the top, bottom and rear walls offset at a right angle to form flaps. Adjacently-disposed ends of the flaps are mitered to establish a 90 corner angle, with complementary half-holes forming clearance holes for fastening screws. The mitered flap ends are bridged by selfretaining fastners secured in place by the fastening screws. The housing may have an open end with the housing top and bottom spaced apart by bracing members. Similar fasteners bridge adjacently-disposed por tions of the bracing members and the flaps which extend from the housing top and bottom.  
  An object of this invention is the provision of a rigid housing made of a relatively-thin metal sheet.  
  An object of this invention is the provision ofa sheet metal housing having corners reinforced by selfretaining fasteners.  
  An object of this invention is the provision of a housing having sides defined by flaps formed by offsetting portions of the housing top, bottom and sides, the corner portions of the flaps being bridged by self-retaining fasteners.  
  The above-stated and other objects and advantages ofthe invention will become apparent from the following description when taken with the accompanying drawings. It will be understood, however, that the drawings are for purposes of illustration and are not to be construed as defining the scope or limits of the invention, reference being had for the latter purpose to the claims appended hereto.  
 BRIEF DESCRIPTION OF THE DRAWINGS In the drawings wherein like reference characters de note like parts in the several views:  
 FIG. 1 is a top plan view of a sheet metal housing;  
 FIG. 2 is a side elevational view thereof;  
 FIG. 3 is a bottom plan view thereof;  
 FIG. 4 is a front elevational view thereof;  
 FIG. 5 is a rear elevational view thereof;  
  FIG. 6 is an enlarged, fragmentary plan view ofa corner of the housing as made in accordance with this invention;  
 FIG. 7 is a side elevational view of a corner fastener;  
 FIG. 8 is a top plan view of the fastener;  
 FIG. 9 is a bottom plan view of the fastener;  
 FIG. 10 is a front elevational view of the fastener;  
 FIG. 11 is a side elevational view of the fastening screw;  
  FIG. I2 corresponds to FIG. 6 and shows a fastener secured to the mitered ends of the side wall flaps of the housing;  
  FIG. 13 is an enlarged fragmentary plan view of another corner of the housing made in accordance with this invention;  
  FIG. 14 corresponds to FIG. 13 and shows a fastener applied to such corner of the housing;  
  FIG. 15 is a rear elevational view showing two housings secured together, portions being shown in cross section; and  
  FIG. I6 is a corresponding front elevational view, with portions shown in cross-section.  
 DESCRIPTION OF PREFERRED EMBODIMENT Referring to FIGS. 1-5, there is shown a housing of the type used to enclose and support electrical components and circuitry. The housing is formed by bending a relatively thin sheet of aluminum to form a top 10, a bottom 11 and a back 12. A pair of braces 13 and 14, made of the same material as the housing, have offset end portions 15 and 16, respectively, said end portions being secured to the top and bottom of the housing by rivets l7 and 18, respectively. These braces serve to support the top and bottom in proper spaced position at the open end of the housing. As shown, the top, bottom and back of the housing are provided with a plurality of holes and slots for purposes of ventilation and for receiving screws used to fasten components in place. Side portions of the top and bottom are offset at a right angle to form the flaps 20 and 21. The side portions of the back 12 are similarly offset to form two flaps, the flap 22 being visible in FIG. 2. Adjacently-disposed ends of the flaps are mitered to establish corners as indicated by the reference letters a and 1:. Similar corners are formed between the ends of flaps located on the other side of the housing. At the open end of the housing, the top 10 and the bottom 11 each have reduced-width end portions 23 and 24, which portions extend between the braces 13 and 14, whereby the braces lie flush with the flaps 20 and 21.  
  The side of the housing, FIG. 2, is open except for the flaps 20-22 and the brace 13. The other side of the housing has a similar configuration. The described housing, being made of relatively thin sheet metal and having open sides and an open end, does not have sufficient rigidity to resist twisting and bending forces applied thereto and, therefore, it is necessary to reinforce the corners thereof. Heretofore, the corners have been reinforced by welding or by means of gussets riveted to the housing corners. In accordance with this invention, the housing corners are reinforced by means of selfretaining fasteners as, for example, the fastener 26 shown in FIGS. 7-10. Such fastener, made of spring steel and having a U-shaped cross-sectional configuration, comprises spaced leg portions 27 and 28, the leg portion 28 being provided with a clearance hole 29 for a fastening screw 30, see FIG. 11. The leg portion 27 is provided with raised tips 31 and 32 which serve as threads for the fastening screw. The free ends of the fastener are spaced apart a distance equal to the thickness of the metal of which the housing is made, and a corner 33, of the leg portion 27, is offset upwardly to facilitate pressing the fastener onto a metal sheet.  
  Reference now is made to FIG. 6 which is an enlarged fragmentary view of a corner of the housing as, for example, the corner shown in FIG. 2. Two halfholes are punched in the flat sheet prior to bending the sheet to form the housing. When the sheet is bent to form the flaps 21 and 22, the half-holes 35 and 36 form a clearance hole for the screw 30 shown in FIG. II. The fastener 26 is then pressed into place as shown in FIG. 12, with the fastener leg 28 being in engagement with the outer surfaces of the flaps and the other fastener leg 27, see FIG. 8, being in engagement with the inner surfaces of the flaps. When fully tightened, the fastening screw 30 causes the leg portions of the fastener to clamp tightly about the end portions of flaps. The half-holes 35 and 36 are located such that when the screw 30 passes therethrough the fastener forms a wedge between the edge walls of the flaps. All of the mitered corners of the housing are similarly reinforced by means of the described fasteners.  
  Reference now is made to the enlarged. fragmentary view of FIG. 13 showing a housing corner corresponding to the corner c in FIG. 2. Half-holes 38 and 39 are formed in the flap 2] and the brace 13, respectively. Additionally. a slot 37 is formed in the brace. the upper wall of the slot being aligned with the side edge of the flap. When a fastener 26, FIG. 14, is secured in place by the screw 30, approximately one-half of the base of the fastener lies within the slot formed in the brace, while the remaining portion of the fastener base en gages the side edge of the flap 2]. The other three housing corners at the open end of the case are similarly reinforced by fasteners.  
  The described corner-reinforcing fasteners also serve as means for securing two housings together in side-byside relationship. The rear elevational view of FIG. shows two housings 40 and 40&#39; having tops 10, 10&#39; and backs l2, 12&#39;, respectively. The fastener screw 30 passes through a lock washer 41, the half-holes formed in the mitered ends of flaps 42&#39; and 43&#39;, the flat leg portion 28 of the fastener, the half-holes formed in the mitered ends of flaps 42 and 43, and the fastener leg portion 27. The adjacent lower corners of the two housings are similarly secured together, the flat leg portion 28 of the associated fastener being visible in this particular view.  
  The front ends of the two housings 40 and 40&#39; are secured together by means of fasteners positioned as shown by the fastener 26 in FIG. I4. Referring to the front elevational view of FIG. I6, a fastener 26 has its base extending into the slot formed in the brace 14 and the fastener leg portions 27 and 28 span portions of the brace and the associated flap 45 formed by the offset side portion of the top 10. The fastener screw 30 passes through a lock washer 41, the half-holes formed in brace 14&#39; and the flap 45&#39;, the flat leg portion 28 of the fastener, the half-holes formed in the brace 14 and the flap 45, and the fastener leg portion 27. The lower corners of the two housings are similarly secured together, as shown.  
  Having now described the invention, what I desire to protect by letters patent is set forth in the following claims.  
 I claim:  
  1. An arrangement for reinforcing a corner ofa sheet metal housing, which corner is formed by two portions of the housing lying in a common plane and having adjacently-disposed ends, said arrangement comprising,  
 a. complementary half-holes formed in the said ends,  
 b. a metal fastener member of U-shaped crosssectional configuration and having leg portions bridging the said ends, one leg portion being provided with a hole and the other leg portion being provided with a screw thread, and  
 c. a screw threaded into said screw thread, the shank portion of the screw passing through the hole in the said one leg portion and through said half-holes.  
  2. The arrangement recited in claim I, wherein the said two portions of the housing are offset flaps extending from adjacent walls of the housing; wherein the adjacently-disposed ends of the flaps are mitered at an angle of substantially 45; and wherein the base of said fastener member is in engagement with side walls of the flaps.  
  3. The arrangement as recited in claim 1, wherein the said two portions of the housing are a brace spanning opposite walls of the housing and an offset flap formed in one of such walls.  
  4. The arrangement as recited in claim 3, wherein the said brace includes a slot aligned with a side edge of said flap; and wherein the base of said fastener member extends into said slot.  
 5. A sheet metal housing comprising,  
 a. a back formed integrally with a top and a bottom,  
 b. first and second flaps formed integrally with said top and extending toward said bottom,  
 c. first and second flaps formed integrally with the bottom and extending toward said top,  
 d. first and second flaps formed integrally with said back, the said first flaps lying in a first common plane and having adjacently-disposed ends, and the said second flaps lying in a second common plane and having adjacently-disposed ends,  
 e. complementary half-holes formed in each of the said adjacently disposed ends,  
 sectional configuration, each member having leg portions bridging adjacently-disposed ends of the flaps, one leg portion being provided with a hole and the other leg portion being provided with a screw thread; and  
 g. individual screws threaded in said threads, each screw having a shank passing through the hole of the fastener member and through the half-holes of the associated flaps.  
  6. A housing as recited in claim 5, wherein the adjacently-disposed ends of the flaps are mitered at an angle of substantially 45.  
  7. A housing as recited in claim 6, including a first brace secured to the said top and bottom, said brace lying in the said first plane and having a side edge adjacent to end edges of the first flaps formed integrally with the said top and bottom; a second brace secured to the said top and bottom, said brace lying in said second plane and having a side edge adjacent to end edges of the second flaps formed integrally with the said top metal fastener members of U-shaped crossan end edge of an associated flap, and each fastener member having a base extending into a slot of a brace; and individual screws threaded into the screw thread of an associated fastener member.  
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