US3211824A - Stud insert for shielding electrical conductors, and the like - Google Patents

Description

Oct. 12, 1965 HElMAN 3,211,824

STUD INSERT FOR SHIELDING ELECTRICAL GONDUCTORS, AND THE LIKE Filed Jan. I50, 1964 INVENTOR JORD N L. HEIMN Z1 ATTORNEY United States Patent 3,211,824 STUD INSERT FOR SHIELDING ELECTRICAL CONDUCTORS, AND THE LIKE Jordan L. Heiman, Olivette, Mo., assignor to International Oil Burner Company, St. Louis, Mo., a corporation of Missouri Filed Jan. 30, 1964, Ser. No. 341,358

8 Claims. (Cl. 17448) The present invention relates to an article for shielding electrical wires and the like, to be inserted in the studs of walls of mobile houses, for example; and to the method of constructing such walls.

In the construction of hollow walls for mobile homes, the exterior sheet, usually a metal sheet such as aluminum, and the interior sheet, which may be a decorative interior sheet of plywood, are secured to closely spaced wooden studs which support and structurally reinforce the wall. Electrical wires are customarily concealed within the walls by stringing them through notched-out grooves provided in the wooden studs.

Because of the close spacing of the wooden studs, it is difficult to position a drill between them to bore holes through which the electrical wires may be strung. Therefore, to expedite assembly of the walls, a routing tool is passed over the inside surface of the wooden studs,

thereby providing the notched-out grooves which receive the electrical wires.

This method has not proved satisfactory where the inner and outer wall boards are secured to the studs by randomly spaced fasteners. One difliculty encountered has been that the randomly spaced nails, staples or other fasteners pierce the insulation of the electrical wires, causing short circuits to be developed. Such short circuits are not detected until the wall has been completely assembled. If detected at this time, an expensive and time-consuming dismantling of the wall is required to locate and to correct the defect. Another difficulty is that the grooves Weaken the wooden studs, and accordingly, the wall structure.

The general purpose of this invention is to provide a method and article for shielding electrical wires concealed in hollow walls, wherein all the advantages of customar- .ily employed methods and apparatus are retained, and

none of the aforedescribed disadvantages are encountered. Therefore among the objects of the present invention are the provisions of:

A metal shield for electrical wire which may be readily manufactured without welding or extrusion; a shield having sufficient structural strength to prevent penetration by fasteners and reinforced against inward forces applied to its exterior surface;

A metal shield for hammering into a wooden stud groove which exhibits spring-like defiectance on insertion to tightly engage the shield therein;

A metal shield for hammering into a wooden stud which is open to receive electrical wires therein and is closeable upon hammering into the stud; and

A method of building hollow Walls of the type including wooden studs to which structural and decorative sheets are to be fastened, whereby bending strength of the grooved studs is restored by the compressive strength of the shield and the tensile strength of the structural sheets fastened thereto.

In the present invention these purposes (as well as others apparent herein) are achieved generally by providing a one-piece tubular shield for electrical conductors, adapted to be driven into a groove in a wooden stud over which structural sheets are to be fastened. The shield consists of an elongated metal strip of sutficient structural strength to prevent penetration by the sheet fasteners.

3,211,824 Patented Oct. 12, 1965 ice The metal strip is bent into a closed, hollow cross-section having unsecured strip ends adjacent to which two substantially plane walls are formed. These walls form a corner; one wall having an unsecured end, at least a portion of which abuts the interior surface of the other wall. Fastening means are provided on two opposite horizontal walls and project outwardly to secure the strip within the grooved stud.

The method utilized in practicing the present invention consists generally of: routing the studs to provide laterally thereacross rectangular notches whose depth do not exceed half the depth of the studs, force-fitting within each rectangular notch a rectangular metal shield member hollow transversely to the stud, inserting electrical wiring through the metal shield member, and randomly fastening the structural sheets to the outer side of the studs. Accordingly, those nails or staples driven into the wall, at the stud locations, which happen to strike the shields will be turned harmlessly aside.

Utilization of the invention will become apparent to those skilled in the art from the disclosures made in the following detailed description of the preferred embodiment of the invention as illustrated in the accompanying drawings, in which:

FIG. 1 is a perspective sketch of the tubular shield showing the reinforcing top wall bent to engage the vertical side wall and the fastening tabs;

FIG. 2 is a plan view of the tubular shield of FIG. 1 illustrating the top portion of the shield and the protruding pointed tab used in securing the shield;

FIG. 3 is a plan view illustrating a modification of the pointed tab used in securing the shield of FIG. 1 to wooden studs;

FIG. 4 is a side edge view of the metal strip as it appears before bending into the tubular shield of FIG. 1;

FIG. 5 is a cross-sectional view of the tubular shield of FIG. 1 shown inserted in a groove provided in a wooden stud which supports interior and exterior surface sheets; and

FIG. 6 is a perspective sketch of a second embodiment of the present invention showing the reinforcing wall with an inwardly protruding tab and the rear wall having arcuately bowed portions extending inwardly.

Referring now to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in FIG. 1 a onepiece tubular shield, generally designated 10, formed to be inserted in notched-out grooves provided in the vertical wooden studs used in the construction illustrated. This tubular shield 10 consists of an elongated metal strip 12 which is bent into an open-ended, rectangular cross section having two unsecured ends 14 and 16. By bending the metal strip 12 in this fashion, two substantially vertical walls are formed to meet two substantially horizontal walls at three bent corners 18 and a fourth, closing corner 20, formed by the intersection of the unsecured end 16 and one of the vertical walls. The two horizontal walls are generally designated as a top wall 22 and the bottom wall 24, while the vertical walls are generally designated as a front wall 26 and a rear wall 28. Preferably the metal strip 12 is cold rolled steel which exhibits a degree of hardness sufficient to prevent penetration by commonly employed sheet fasteners utilized in wall construction. It has been found that 16-gauge coldrolled steel can be readily bent into the configuration illustrated and prevents penetration of the tubular shield 10 by conventional sheet nails, staples, screws, and the tools used in inserting them.

The closing corner 20 of the tubular shield 10 is formed so that, although having unsecured ends, it structurally reinforces itself to resist deformation and inward forces applied to its exterior surface.

To this end, the top wall 22 has a bent margin 30 which extends angu-l-arly, subtending an angle greater than 90 and downward terminating in the unsecured end 16 at the hereinbefore referred to closing corner 20. This unsecured end 16 is presented abuttingly against the interior surface 32 of the shields rear wall 28. Because the bent margin 30 intersects the rear wall 28 inwardly of its terminating unsecured end 514, it reinfior-ces the shields rear wall 28 against inward forces; for example, against nails or screws driven against it in fastening the exterior :aluminum sheet onto the studs. The angularly bent margin '30 presented to the interior surface '32 of the rear wall 28 inwardly of its terminus permits a spring-like deflect-ance of the tubular shield .10 on being driven into the grooves of the studs. This spring-like detlectance allows upper and lower fastening means, generally designated 34, to press into the groove of a wooden stud and tightly engage the tubular shield 10 therein.

The fastening means referred to hereinabove takes the form of integral pointed tabs 84 which project outwardly from the top and bottom walls 22 and 24 of the hollow shield. These tabs 34 are preferably stamped-out, arrowhead-like spikes having their pointed ends extending toward the shields vertical front wall 2 6.

FIG. 3 shows a modified pointed tab 34 especially suited for use where the notched-out groove in the wooden stud has been made too large for :a tight fit between it and the tubular shield 10. The pointed tab 34, like the pointed tabs 34, project outwardly from the top and bottom walls *22 and 24 respectively and toward the front wall 26. However, the pointed tabs 34' are provided with doublepointed tips 36 forming a V-shaped notch 37 therebetween. If such loose fit exists between the tubular shield 10 and such groove in the wooden stud, a nail may be driven through this notch 37 and into the wooden stud to secure the tubular shield within the notched-out groove.

FIG. 4 shows the metal strip 12 as it appears prior to the bending operation which closes it to provide the finished product shown in FIG. 1. The metal strip 12 is cut off from a longer strip of the material to form the unsecured ends 14 and 1 6. In the next operation the pointed tabs 34 and the bent-down margin 30 are formed. The final operation involves the bending of the metal strip -12 at the points indicated by the dashed lines I, whereupon the open-ended tubular shield 10 of FIG. 1 results.

In the construction of hollow walls for mobile homes, where closely spaced wooden studs have tension-resisting structural sheets fastened to their outer sides and through which it is desired to install electrical wiring, a routing tool is passed over the interior edge surfaces 38 of the wood-en studs 39 to provide the notched-out grooves 40 (see FIG. for a single stud 39 :and groove 40). In order not to substantially weaken the Wooden studs 39 therectangular grooves 40, which extend transversely across the entire interior edge surface 38 of the studs, should not be permitted to exceed half of the depth of the stud which separates the interior and exterior sheets to be applied. The tubular shield .10 is then force-fitted into a notchedout groove 40 of a rear wall 28 iir'st, and driven therein by hammering the front shield wall 26 until it is flush with the interior edge surface '38 of the stud 39. As the tubular shield is driven into the rectangular, notched-out groove 40 the bent-down margin 30 of its top wall 22 reinforces the rear wall 28 to prevent it from being deflected into the hollow interior of the tubular shield. Nevertheless, the spring-like defiectance of the shield .10 permits wedge-like engagement of its pointed tabs 34 into the woo-den stud 39, The tabs 34 serve as barbs to prevent the shield from moving transversely or outwardly from the groove 40.

Electrical Wiring may then be inserted through the metal tubular shield member 10. After the electrical wires have been installed within the tubular shield !10 in the stud, an interior sheet 42, of decorative plywood or the like, may

then be randomly fastened to the wooden studs 39 by the fasteners 44, for example nail-s, screws, staples, or the like. if any fasteners 44 be directed toward the electrical conductors 46, they are deflected by the metal tubular shield M as shown, thereby preventing the short circuiting of the electrical conductors 46. In like manner, when an exterior structural sheet 48 is secured by randomly spaced fasteners 44, interference with the electrical conductors 46 by the fasteners 44 is prevented by the rear wall 28. Because the rear wall .28 is reinforced by the top wall margin 30, a fastener 44, so driven, will not cause collapse of the rear wall 28 against the conductors 46-.

In addition to shielding the electrical conductors 44, the tubular shield .10 rest-ores the structural strength of the stud by contributing its compressive strength to replace that lost by grooving the wood. The structural sheets 42, 48, which are strong in tension work with the studs 39 to resist bending loads. When the interior structural sheet 42 is in tension, its strength in tension is adequate to resist the imposed load, regardless of the groove. If the bending load be reversed, to put the interior in compression, the tubular shield 10 resists such compression. Accordingly, the present method prevents structural failures which might otherwise occur due to the weakening of the "studs by the grooves 40.

In FIG. 6, there is shown a modification of the tubular shield member 10' wherein the top wall 22', rather than having a bent down margin portion, extends horizontally throughout its entire length to terminate in an unsecured end 16. This unsecured end 16 is provided with an indented, inwardly protruding reinforcing tab '50 which serves to abut the interior surface of the rear wall 2 8' inwardly of its terminus unsecured end 14'. Preferably the tab 50 abuts the rear wall 28' intermediate the side edges at the approximate middle thereof. The rear wall 28 consists of :a flat, plane mid-portion 52 which terminates on each side in inwardly-extending, arcuately bowed portions 54, The inwardly extending bowed portions 54 serve to abut the inner surface of the topwall 22' and reinforce same.

In fabricating the tubular shield member 10, the bending operation is such that the bottom wall 24 and the rear wall .28 form an angle greater than as shown in FIG. 6. This provides an opening 56 between the unsecured ends .14 and 16' through which electrical wiring may be inserted prior to closing. Upon force-fitting the shield member 10' into a wooden stud, the rear wall 28' is bent around the corner 18' to close the opening 56 and the tabs 34' secure it to the stud. Reinforcing tab 50 impends the bending of the rear wall 28' past the vertical position and the bowed portions 54 of the rear wall 28' reinforce the upper wall 22 in this vertical position.

Thus, it may be seen that the present invention provides a unique tubular shield which may be utilized in the construction of hollow, stud-reinforced walls to house and protect electrical wiring installed therein and simultaneousy avoid lessening the structural strength of the wall stu s.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. For example, instead of driving the fasteners at random, the steel shield can be located magnetically, and the fasteners may then be spaced to avoid them. Furthermore, it should be understood that the steps of inserting the electrical wires in the metal shield member and force-fitting the shield members into the stud are interchangeable in time sequence. For example, in using the shield member which is partially open after fabrication, the electrical wiring can be inserted and then the shield member force-fitted into the stud. The reverse operation is most practical using the shield member having the bent down margin. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

Iclaim: 1. A one-piece tubular shield for electrical conductors adapted to be inserted in wooden studs over which structural sheets are to be fastened, comprising an elongated metal strip of suflicient structural strength 5 to prevent penetration by the sheet fasteners, said metal strip being bent into an open-ended hollow rectangular cross-section having unsecured ends and characterized by two substantially vertical walls meeting upon closure with two substantially horizontal walls at three bent corners and at a fourth corner,

said fourth corner being defined by one of said horizontal walls presenting upon closure one of said unsecured strip ends abuttingly against the interior surface of that adjacent vertical wall which has its terminus in the other unsecured strip end whereby said vertical wall is reinforced against inward forces applied to its exterior surface.

2. The one-piece tubular shield as defined in claim 1,

wherein said horizontal walls have fastening means projecting outward therefrom whereby said shield may be secured within the wooden studs.

3. The tubular shield as defined in claim 2, wherein said fastening means are integral pointed tabs which project toward that vertical wall which terminates in two bent corners.

4. The tubular shield as defined in claim 3, wherein the fastening means are integral double-pointed tabs, each having a notch between the double points thereof,

whereby in the event of loose fit of the shield within the stud, a nail may be driven within such notch to secure the shield to the stud.

5. A one-piece tubular shield for electrical conductors adapted to be driven into a groove in a wooden stud over which structural sheets are to be fastened, comprising tially plane walls forming a corner, one said wall having an angularly bent margin adjacent to its such ends to abut the interior surface of the other said wall,

whereby spring-like deflectance of the metal on being so driven into such groove tightly engages the shield therein.

6. The tubular shield as defined in claim 5, wherein said angular bend of said margin subtends an angle greater than 7. A one-piece tubular shield for electrical conductors adapted to be driven into a groove in a wooden stud over which structural sheets are to be fastened, comprising an elongated metal strip of sufficient structural strength to prevent penetration by the sheet fasteners, said metal strip being bent into a hollow cross-section including an angle greater than 90 whereby unsecured strip ends thereof are spaced apart to provide an opening communicating with the interior of said bent metal strip,

there being formed adjacent to said unsecured strip ends two walls, one of said walls having an inwardly protruding tab at its said strip end to about the interior surface of the other said wall,

whereby upon being driven into such grooved stud the said angle is reduced to 90 and the spaced apart ends are closed together and said inwardly protruding tab reinforces the other said wall and prevents the reduction of said angle to less than 90.

8. The tubular shield as defined in claim 7, wherein said other wall is characterized by inwardly extending bowed portions which upon closure are caused to be aligned below the inner surface of the one said wall.

References Cited by the Examiner

Claims (1)

1. A ONE-PIECE TUBULAR SHIELD FOR ELECTRICAL CONDUCTORS ADAPTED TO BE INSERTED IN WOODEN STUDS OVER WHICH STRUCTURAL SHEETS ARE TO BE FASTENED, COMPRISING AN ELONGATED METAL STRIP OF SUFFICIENT STRUCTURAL STRENGTH TO PREVENT PENETRATION BY THE SHEET FASTENERS, SAID METAL STRIP BEING BENT INTO AN OPEN-ENDED HOLLOW RECTANGULAR CROSS-SECTION HAVING UNSECURED ENDS AND CHARACTERIZED BY TWO SUBSTANTIALLY VERTICAL WALLS MEETING UPON CLOSURE WITH TWO SUBSTANTIALLY HORIZONTAL WALLS AT THREE BENT CORNERS AND AT A FOURTH CORNER, SAID FOURTH CORNER BEING DEFINED BY ONE OF SAID HORI-

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