Foldable filter frame

A foldable filter frame is provided. The filter frame includes a filter media panel and a rectangular support frame surrounding the filter media panel. The support frame included four edge elements. Each edge element has a double-walled construction and is foldable into a position in which a first leg of the respective edge element is generally perpendicular to a second leg of the edge element. An end of at least one of the edge elements that defines a corner of the support frame supports a foldable tab that is receivable in a complementary slot in an end of the other edge element defining the respective corner of the support frame with the tab being arranged in an inner space between the double-walls of the edge element.

FIELD OF THE INVENTION

This invention pertains to air filters used in heating and air conditioning systems.

BACKGROUND OF THE INVENTION

Forced air heating and air conditioning systems commonly include an air filter to remove particulates and other impurities from the circulating air. These air filters generally consist of a filter media (e.g., a fibrous mat or porous foam) that is held within a frame. The frame provides the air filter with mechanical strength and rigidity so as to facilitate mounting of the air filter in the air handling equipment. Frequently, these air filters must be replaced on a periodic basis. Alternatively, the air filters can be designed to be washable.

Unfortunately, the air filters that are commercially available for use in heating and air conditioning systems have a number of shortcomings. For example, the air filters are relatively expensive to transport and store because they are quite bulky despite their lightweight construction. This problem has been alleviated somewhat by filters having frames that are designed to nest in another filter thereby allowing more filters to be stored in a given shipping container. However, even with nestable filter designs, the transport and storage of the filters remains a significant cost issue. Moreover, nestable filter designs, as is the case with many conventional filter designs, tend to be expensive to manufacture, awkward to assemble and somewhat flimsy.

BRIEF SUMMARY OF THE INVENTION

A foldable filter frame is provided. The filter frame includes a filter media panel and a rectangular support frame surrounding the filter media panel. The support frame included four edge elements. Each edge element has a double-walled construction and is foldable into a position in which a first leg of the respective edge element is generally perpendicular to a second leg of the edge element. An end of at least one of the edge elements that defines a corner of the support frame supports a foldable tab that is receivable in a complementary slot in an end of the other edge element defining the respective corner of the support frame with the tab being arranged in an inner space between the double-walls of the edge element.

DETAILED DESCRIPTION OF THE INVENTION

Referring more particularly toFIG. 1, an air filter assembly10is shown that is suitable for use in a heating or air conditioning system. The illustrated filter assembly consists of a filter media panel12that is contained within a surrounding support frame14. The illustrated filter media panel12has a generally planar construction. Alternatively, the filter media can have a pleated or corrugated configuration. Moreover, any suitable filter media can be used including a fibrous fiberglass mat, porous foam or the like.

In this case, the support frame14comprises four side or edge elements16that together define the open center portion through which a fluid such as air can flow to the filter media panel12. The filter media panel12is attached to the edge elements16of the support frame14using any suitable method (e.g., glue, staples or the like). Advantageously, while their lengths may vary depending on whether the filter is square or rectangular, each of the edge elements16has the same configuration. As will be appreciated, this can substantially reduce the cost of manufacturing the support frame.

To maximize the number of filters that can be stored in a given container, the support frame14is constructed such that it can lie flat for shipping purposes and then be folded into a more rigid box frame (seeFIG. 1) prior to installation. To this end, a fold or score line18extends lengthwise through the middle of each of the edge elements16(seeFIG. 2). The score lines18facilitate folding of a first leg20of the individual edge elements16into a position in which it is perpendicular relative to a second leg22of the respective edge element to which the filter media panel12is attached thereby forming an L-shape as shown inFIG. 3. The support frame14is preferably made of a material such as paperboard that is sufficiently flexible to allow the frame to be readily folded.

As is the case with the illustrated embodiment, the edge elements16of the support frame14can have a double-walled construction. This double-walled construction along with the L-shaped configuration of the folded edge elements14(seeFIGS. 1 and 4) makes the fully assembled filter assembly10rigid and strong. As will be appreciated, this strength and rigidity makes the filter assembly easier to handle and install.

To secure the corners of the support frame14, the end of one of the edge elements16defining each corner includes a pair of tabs24that are received in a pair of complementary slots26formed in the end of the other edge element16defining the corner (seeFIGS. 2–4). As noted above, each of the edge elements16has the same configuration, which in this case comprises a first “male” end including tabs24and a second “female” end including slots26. As best shown inFIG. 2, each tab24is connected to the rest of its respective edge element16along a transverse fold or score line28that facilitates bending of the tab24relative to the rest of its corresponding edge element16.

To assemble one of the corners, the tabs24are bent along the score line28into perpendicular relation with the remainder of their corresponding edge element16as shown inFIG. 3. If it has not already been done, the two contiguous edge elements16that will form the corner are then folded along their longitudinal score lines18so that the first and second legs20,22of each of the edge elements16forms an L-shape. In this case, a slot26is provided in the inside facing wall and in the outside facing wall of the perpendicular first leg20of the “female” edge element end forming the corner. Accordingly, the two tabs24of the contiguous “male” edge element end are split with one of the tabs24extending into the slot26on the outside face of the first leg20and the second tab extending into the slot26on the inside face.

Because of the double-walled construction of the edge elements16, the tabs24are received in the inner space between the two walls when inserted in the slots26. As a result, the majority of the tabs24are hidden when the filter support frame14is assembled so as to ensure that they do not become snagged or otherwise damaged in such a manner that the corners become unfastened.

To secure the tabs24in the slots26, each tab24has a notch30formed in an upper edge thereof that engages the upper corner of its associated slot26when the tab24is fully inserted. This locks the tab24in the slot26making the tab resistant to being pulled out of engagement. Thus, when assembled, the corners of the support frame14are rigid and strong. While the use of two tabs at each corner is advantageous in that it increases the strength of the corners, it will be understood that each corner also could be equipped with only a single tab.

A second embodiment of an air filter assembly is shown inFIGS. 5–8. As with theFIGS. 1–4embodiment, the air filter assembly shown in the photos can be stored in a flat condition and then folded into a box-like construction for installation. The primary difference between the first and second embodiments lies in the fastening of the corners once the edge elements16have been folded. As shown inFIGS. 5 and 6, in the second embodiment, a single tab24is provided on one of the edge elements16defining each corner. The tab24is received in a slot26formed in the end of the other edge portion that defines the corner (seeFIG. 7). In this case, the slot26is formed by the two walls of the folded-up portion of the edge element16of the support frame14.