US3428779A - Means for mounting electrical radiant heating wires - Google Patents

Description

Feb. 18, 1969 3,428,779

MEANS FOR MOUNTING ELECTRICAL RADIANT HEATING WIRES W. T. DAVIDSON Filed July 18, 1966 WILLIAM Tl/[UDMI DAV/0S0! INVENTOR.

United States Patent Oihce 3,428,779 Patented Feb. 18, 1969 5 Claims ABSTRACT OF THE DISCLOSURE A nonconductive support strip of a U-shaped crosssection, having one leg of the U adapted for mounting the strip onto a surface and the other leg of the U crenelated to form a plurality of hooks from which anelectric heating wire may be suspended in a series of continuous loops, displays the crenelations in angularly inclined position with respect to the main axis of the strip.

This invention is directed to a method of mounting a radiant heating wire onto a surface such as a ceiling, and to a suport member for use in the method.

The use of radiant heating elements enclosed within structural surfaces, such as radiant heating wires mounted above or within the ceiling of a room is well known. Certain structures such as concrete buildings having unitary concrete floors and ceilings, while being particularly suited in certain regards for use with surface elements, are particularly diflicult to wire, as the concrete surface of the ceilings is not suited for accepting wire supporting devices. One earlier method included the use of U-shaped staples for physically securing the wires to the ceiling. The use has also been proposed of a pair of plastic or other nonconducting support members in spaced-apart backto-back relation being of U-section, one leg of the U being mounted to the ceiling and the other leg of the U being castellated to form a plurality of hooks from which the wire may be suspended in a series of continuous loops.

This latter proposal suffers from the serious disadvantage that the loops so formed are limited in length by the natural sag of the wire, it being impractical to extend the span by increased wire tension due to the nature of the hook-like supports and the natural tendency of the wire to expand when heated.

The present invention provides an electrically nonconductive strip suitable as a wire support member and for interposition as an intermediate support member for electrically heating wires comprising: an elongated flexible body of U-form cross-section having two legs and a bight portion therebetween, one arm of the strip having diagonally extending crenelations defined by a plurality of substantially parallel cut-outs extending through the body of the U-section to the edge of the leg, the crenelations being angularly inclined to the longitudinal axis of the strip.

The strip according to the present invention, while being particularly suited for use as an intermediate wire support, is also completely suitable to be used as a loop spacer for suspending heating wires from a surface.

The support strip according to the present invention is particularly well adapted to facilitate installation of a suspended heating wire because, with a pair of support strips according to the present invention attached to the primary surface such as a ceiling in mutual back-to-backrelation, having a third strip substantially parallel therewith and interposed between the first two strips, the heating wire may be readily looped to and fro between the two outer support strips and introduced beneath the diagonally lying detent portions of the intermediate strip by conforming the wire wth the diagonal inclination of the detents for insertion therebetween, whereafter straightening of the wire either by deformation or increased Wire tension positions the wire in overlying supported relation relative to the respective detent of the intermediate support strip.

The following is a description by way of example of certain embodiments of the present invention, reference being had to the accompanying drawings in which:

FIGURE 1 shows a wiring installation embodying sup port strips according to the present invention;

FIGURE 2 is an end view of the arrangement shown in FIGURE 1; and

' FIGURE 3 is a view from below of an installation as shown in FIGURE 1.

The individual support strips 20 comprise an elongated planar securing strip 21 having a plurality of lengthwise extending ribs 24 on the obverse side thereof. The strip 21 constitutes one leg of a U-section, the other leg of the U being made up of tooth-like projections 22 with slots 23 therebetween extending outwardly from the bight of the U-section, being inclined to the axis of the strip.

The support strips 20 are electrically nonconductive, being generally extruded in thermo plastic material, with the slots 23 being formed in a subsequent operation.

It will be seen that a single support member 20 in accordance with the present invention may be utilized intermediate of wire support members according to the prior art, to permit extended spans of heating wire being strung. This has the particular advantage that the number of wire bend-ing operations necessary to cover a given area of ceiling may be considerably reduced. In accordance with prior practice, when intermediate support members in accordance with the present invention were not available, it was necessary in the case of large area coverage to make a series of independent installations in order to subdivide the total area being wired into a number of strips of suitable span. However, by using one or more intermediate members in accordance with the invention the span can be so extended that much larger surfaces may be treated as a single entity, thus reducing the quantities of material required and also greatly facilitating the wire suspending operation, while at the same time improving the reliability of the installation due to the reduced number of wire turns or bends required with a corresponding reduction in wire stress both from the point of view of bending and tensioning.

The use of slots inclined at 45 to the strips main axis permits reversal of the support strip. Slots inclined to the strip in the range from 20 to 70 are contemplated.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electrically nonconductive intermediate strip in cooperation with a pair of outer electrically nonconductive strips suitable for supporting electrical heating wires from a surface, said intermediate strip comprising: an elongated, flexible body of U-form cross section having two legs and a bight portion therebetween, one leg of said strip having crenelations defined by a plurality of cut-outs extending through the body of the U-section to the edge of said leg, said crenelations being angularly inclined to the longitudinal axis of the said strip.

2. An electrically nonconductive strip as claimed in claim 1 wherein the crenelated leg is of lesser width than the other leg of the strip.

3. An electrically nonconductive strip as claimed in claim 2 further comprising longitudinally extending ribs on the outer face of the other said leg of the strip, to facilitate atachment of said outer face to a supporting surface.

4. An electrically nonconductive strip as claimed in claim 1, wherein said crenel-ations are substantially parallel sided, being inclined to the longitudinal axis of said strip at an included angle in the range from 20 to 70.

5. In the method of suspending radiant heating wire from a surface such as a ceiling, wherein a length of electrical resistance wire is suspended in a series of continuous loops between a pair of support member secured in back-to-back, substantially parallel spaced arrangement, and wherein the distance between such support members permits undue sage in said Wire loops, particularly in the heated condition, the improvement comprising: providing an intermediate support member lying between said pair of support members and having a series of substantially planar wire-engaging detent members extending therefrom substantially parallel with said surface and inclined to the axis of said heating wire; inserting an intermediate portion of said wire loops between adjacent ones of said detents, and tensioning said loops to the extent that said inserted intermediate wire portions are engaged in over- 4 lying supported relation by said inclined detent members, whereby intermediate wire support is provided to the wire by said detents.

References Cited UNITED STATES PATENTS 2,940,481 6/1960 Hunter 2l9---213 X 3,200,236 8/1965 Geyer 219-213 FOREIGN PATENTS 20,742 10/ 1935 Australia. 752,020 1/ 1967 Canada. 391,895 5/1933 Great Britain.

RICHARD M. WOOD, Primary Examiner.

C. L. ALBRITTON, Assistant Examiner.

US. Cl. X.R.

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