Air filter frame

July 18, 1961

2,992,702

C. S. REID

AIR FILTER FRAME

Filed July 9, 1958

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ATTORNEYS.

United States Patent Office _p., _{d 5} f’⁹⁹²;⁷®?

Patented July 18,1961

2,992,702 AIR FILTER FRAME

Charles S. Reid, New York, N.Y., assignor to Continental Can Company, Inc., New York, N.Y., a corporation of New York

Filed July 9,1958, Ser. No. 747,438 2 Claims. (Cl. 183—49)

The invention relates to a frame to hold air filtering material such as spun glass, for filter elements such as those now widely used in air conditioning units for buildings and homes.

According to my invention the filter frame comprises a body made of complementary half sections, each of which consists of a single sheet of paperboard and has a flat perforate face and two opposed tubular edges of generally rectangular form. The two sections are joined together with their flat perforate faces in spaced parallel relation and with the opposed tubular edges of one section arranged at right angles to those of the other section. The tubular edges of each section are secured to the inside edges of the flat perforate face of the other. These tubular edges are constituted by folded and glued edge portions of the sheet. I have discovered that when the individual sections, or components, are constructed in a flat folded form in which the two opposed tubular edges are collapsed inwardly, erection of the tubular edges will bias the flat perforate face inwardly. What happens is that the face takes the form of an inward bow. The result of this is that after the filter element has been inserted, the perforate face of the frame springs firmly against the face of the filter element. Another advantageous result is that the tubular edges themselves are likewise biased inwardly to close with the edges of the filter element. This action is further assisted by the tendency of the inwardly bowed faces of the frame to pull the opposed tubular edges together, so that in the completed assembly the frame snugs tightly against both the faces and edges of the filter element. The inward bias of the faces and edges of the frame is produced by the “fight” of the paperboard stock, and this action is enhanced by the fact that the fight of the stock occurs at each of the several corners of the tubular edges of the complementary frame components.

With reference to the drawing, I here describe the best mode contemplated by me for carrying out my invention.

FIG. 1 is an end elevational view of one of the frame components as constructed in flat folded form.

FIG. 2 is an end elevational view of the same frame component with the tubular edges erected for assembly with the filter element.

FIG. 3 is a perspective view illustrating the final step in assembling the component with another component of like construction.

In these views we see an air filter frame of paperboard and the like comprising a body made of complementary half sections, each of which consists of a single sheet of paperboard and has a flat perforate face 4 and two· opposed tubular edges 5 of generally rectangular form constituted by folded edge portions of the sheet. The perforate faces of the frame form a lattice or screen which holds the filter material while permitting relatively free passage of air through the filter. Preferably the paperboard is scored at the several lines of folding, and the edges of the sheet glued to the backs of face panels 4 as at 8. The two sections are joined together with their flat perforate faces in spaced parallel relation and the opposed tubular edges of one section arranged at right angles to those of the other section, and the tubular edges of each section are secured to the inside edges of the flat perforate face of the other, i.e. over the area indicated by the stippling at 6 in FIG. 3. For this purpose a suitable adhesive may be applied to the edges of the tubes. If desired a pressure sensitive adhesive coating may conveniently be used, such as a suitable adhesive coating of the kind which will produce adherence only upon contact between two similarly coated surfaces. Or in some cases a thermoplastic adhesive may be preferred.

FIG. 2 illustrates the effect of erecting the tubular edges of one of the frame components which has been constructed in a flat folded form in which these edges are collapsed inwardly. Notice the inward bowing of the face 4 of the component as seen in this view. Insertion of the filter element 7 as in FIG. 3 flattens out the face 4 and tends to square up the edges 5 of the frame component, retaining an inward bias of the face 4 and the tubular edges 5 themselves being biased inwardly in the directions indicated by the arrows a to close with the edges of the filter element. In the upper part of FIG. 3 we again see the inward biasing action, this time with reference to the second of the two frame components. As the second component is pressed downwardly into its assembled relation with the first component, its face flattens out and the edges of the tubes 5 of each component are secured to the inside edges of the face 4 of the other component. In the completed assembly, by reason of the special biasing action I have described, the frame snugs tightly against both the faces and edges of the filter element.

The terms and expressions which I have employed are used in a descriptive and not a limiting sense, and I have no intention of excluding such equivalents of the invention described as fall within the scope of the claims.