Adjustable Filter Assembly

Abstract

A frame assembly for a filter or the like which is adapted to be inserted in apertures of buildings such as windows or doors or the like. The frame assembly is telescopically adjustable in two different directions for being accommodated by different size and shape apertures, and is provided with an elongate clamp at each telescopically adjustable portion for holding the adjustment and for rigidity and strength. A filtering material is disposed within the frame assembly and is provided with a retaining screen at each of its major surfaces.

Description

This invention relates to a frame assembly and more particularly to a frame assembly for a filter for purifying air and other fluid media, with particular emphasis on purifying the air moving into a building.

In apartment buildings constructed today, an inherent forced air flow occurs through each of the apartments in the building, usually due to the use of ventilation fans associated with ventilation ducts leading into each apartment in the building. In addition air flow occurs in the areas of the windows and doors of the apartment causing the undesirable result of deposits of dirt in the vicinity of such windows and doors. At the window, the dirt is usually deposited on the inside window ledge, while at the door, the dirt is usually caught at the base of the door in the carpeting, which acts as a filter letting the air pass through to the outside while catching the dirt. Such a situation is a problem requiring almost constant attention due to the rapid build-up of dirt deposits in these forced air situations, especially in urban areas which are always high in air pollution and which contain the majority of apartments.

Accordingly, it is desirable that the problem of dirt carried by the air flowing into these apartments be eliminated, such as by use of a filter.

In addition to this basic problem, another problem arises in the selection of a particular filter to overcome the basic problem. The filters presently available have frame assemblies which generally fall into two basic categories. The first category consists of the type wherein the frame elements are made of a structurally rigid material such as wood or metal. Due to the inherent strengths associated with such materials little or no reinforcing is required at the interconnecting junctures of the frame elements, even when the frame elements are relatively movable for adjustment purposes. Typical examples of such type of frame elements are shown in U. S. Pat. No. 2,175,903 to Lichtman and U. S. Pat. No. 2,624,405 to Lynch. In the telescopically adjustable frame assemblies shown in these patents, the strength of the material used in the frame elements is sufficient to resist significant flexion in the vicinity of the telescopically adjustable portions of the frame assembly. Although locking clamp assemblies are provided at the telescopically adjustable portions of the frame assembly, their purpose is merely to fix the relative position of the various frame elements with respect to each other and they provide little or no structural reinforcement to the frame assembly because the frame assembly is already sufficiently strong for its diverse applications. The second category consists of the type wherein the frame elements are made of a less expensive and less rigid material such as cardboard or the like. Typical examples of such type of frame elements are shown in U.S. Pat. No. 3,237,387 to Haugen et al. and U. S. Pat. No. 2,965,197 to Dow et al. These patents show cardboard type frame elements which are not adjustable relative to each other and which, if made adjustable, would have resulted in a structure which was inherently weak and would therefore have been inadequate for many filter applications. In summary, although cost factors indicate the desirability of a filter using a less expensive adjustable cardboard type frame, the mere inclusion of an adjustability feature in such a filter is self defeating due to the severe reduction in overall frame strength.

It would therefore be desirable that a filter be designed which is adjustable to fit different size building apertures, be inexpensive, and be reasonably durable, and since in many applications it will be exposed to the elements, it is desirable that it also be weatherproof. It is with such objects in mind that the instant invention was perceived.

In addition, it is an object of this invention to provide an improved frame assembly.

It is a further object of this invention to provide an improved apparatus for purifying air and other fluid mediums.

It is still a further object of this invention to provide an improved apparatus for filtering air passing through a building.

In accordance with the above stated objects, an adjustable frame assembly is provided which is capable of accommodating a filtering material and a plurality of retaining screens for the filtering material. A plurality of elongate clamps, preferably of plastic, positioned at the adjustable portions of the frame assembly provide rigidity and strength to the frame assembly while holding the frame elements in an adjusted position while it is disposed in a window or door aperture or the like. The frame assembly is fabricated of a cellulose based material such as cardboard or paper which is preferably weatherproofed such as by wax treating or by other diverse well known processes. The frame assembly may also be fabricated of other materials including plastic, wood, metal, or any combination of such materials.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of the invention as illustrated in the accompanying drawings.

In FIG. 1 is shown a perspective view of a filter apparatus employing the frame assembly disposed within the aperture of a slidable window or door of a building.

In Fig. 2 is shown a perspective view of a filter apparatus employing the telescopically adjustable frame assembly.

In Fig. 3 is shown an enlarged cross section view taken along the line 3--3 of FIG. 2.

In Fig. 4 is shown a perspective view of the clamp for retaining and strengthening the frame assembly.

Referring now to FIG. 1, a filter employing the telescopically adjustable frame assembly, shown generally at 10, is shown in use disposed within and abutting the framework 22 of the aperture of a building 23 and being abutted at one edge by a slidable partition 21 associated with the framework, which partition may take form of a slidable door or window or the like. An edge sealer (not shown), such as tape, may be employed to seal the joints between the building framework and partition and the frame assembly.

With reference to Figs. 2 and 3, the frame assembly comprises four L shaped frame elements 11, 12, 13, 14 which are telescopically interfitted to form a parallelogram. Each frame element is channel shaped, having an opening along its length to receive a sheet of filter material 16, preferably fibrous but it may be of other known types, and retaining screens 15 which are positioned on both sides of the filter material to keep it from billowing. The adjacent frame elements have their mating portions in slightly different sizes (see Fig. 3) to allow for the telescopic effect. The frame element material is a cellulose based material such as cardboard, paper or the like which is preferably weatherproofed in any well known manner such as by wax treating or the like. The frame elements may also be made of other materials as well, including plastic, wood or metal and a frame assembly may comprise a plurality of frame elements each of a different material.

An elongate clamp 17 is provided at each of the telescopic portions of the frame assembly to both strengthen the frame assembly and retain the frame assembly in any desired predetermined size or shape within the confines of its adjustment limits. The clamp is preferably made of rigid plastic but other rigid materials including cardboard or other stiff cellulose based material or metal may also be used.

When employing the above referred to other materials for the frame elements, the use of the elongate clamps 17 of this invention enable a lighter gauge material to be used than would normally be expected due to the geometry of the clamps, which are substantially longer than they are deep or wide.

With reference to FIG. 4, the clamp is shown to define an elongate channel 30 formed by first and second side walls 31 and an interconnecting base wall 32. The ends of the clamp are open to enable the clamp to slide over the frame elements being supported and retained thereby. In addition, the clamp has first short wall portions 33 extending substantially perpendicular from each side wall and second wall portions 34 extending substantially parallel to the first short wall portions 33 and substantially perpendicular to the base wall 32. The length of the first and second short wall portions is shown to be commensurate with the overall length of the clamp but it may be of a greater or lesser dimension as well. The dimensional extent of the first wall portions is such as to enable reasonably free slidable movement of the clamp along one frame element, and more limited movement along two adjacent frame elements forming a telescopic connection, with the retention of the overall telescopic connection occuring due to a friction fit between the inside surfaces of the clamp and the associated frame elements.

With reference to the adjustability feature of the instant invention, it is apparent that with a particular sheet size for the filter material and associated screens, the frame elements can be adjusted no more than the height of their side walls without exposing the edge of the filter material and screens. However, the limit of adjustability may be increased by cutting off equal portions of the filter material and screens to thereby allow the frame assembly to assume a much smaller size, or by providing a plurality of different size filter materials and screens which are selectively chosen in accordance with the particular aperture to be serviced.

While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that changes in form and details may be made thereto without departing from the spirit and scope of the invention. For example, the frame assembly for the filter may take the shape of a triangle or other regular or irregular geometric configuration. In addition, each of the four corners of the frame assembly may be rounded or assume other shapes rather than at right angles, and the channel formed by the frame elements and clamps may be rounded or assume other shapes rather than squared off as shown. The elongate clamp may also take a hairpin form such as defined by walls 31, 33, 34 of Fig. 4, which may be friction fitted or held in other ways to the frame assembly such as by rivits or crimping. Further, where the particular aperture receiving the filter has insufficient means to retain it, the filter may be provided with additional means for such purpose, such as mounting brackets or the like affixed to the frame assembly. Therefore, it is not intended to limit the scope of the present invention to the above described preferred embodiment, but that scope should only be determined by the following claims.

Claims

What is claimed and desired to be secured by Letters Patent is:

1. An adjustable filter assembly for use in purifying air entering an aperture of a building comprising:

a frame assembly comprising first and second cardboard frame members, each of said frame members comprising a first and second leg portion and an intermediary portion interconnecting said leg portion, the leg portions of the first frame member being interfitted with the leg portions of the second frame member to form a telescopically adjustable parallelogram, each of said frame members having a continuous recessed channel along its entire length facing the inner area defined by said parallelogram for receiving a filter material;

a sheet of fibrous filter material contained within the confines of the frame assembly and having its edge portions disposed within the channels of the frame members;

first and second screens positioned on opposite sides of the fibrous filter material, each of said screens having their edge portions disposed within the channels of the frame members, for preventing billowing of the filter material during use; and

a pair of substantially rigid clamps, each comprising a pair of parallel sidewalls connected together by a base portion for frictionally mating with an outer surface of said interfitted leg portions, and wherein the ends of the sidewalls farthest removed from the base portion are turned back and inward in hairpin configuration to frictionally engage an inside surface of the channel at the interconnections, each of said clamps being substantially longer in the direction of the line formed by the intersection of a side wall and the base portion than along its width or height.