Patent Description:
A typical home or business HVAC air-handling system requires periodic or occasional replacement of air filters. Consumers are burdened either with frequent trips to purchase replacement filters or with acquiring and storing a number of replacement filters. However, HVAC air filters are generally large and somewhat fragile. Consumers are also burdened with finding appropriately sized replacement filters, and because air-handling systems have dimensions that vary from unit to unit and there is no specific industry standardization in place. Indeed, success in finding the needed correct size replacement filter is not assured on any given trip to a brick-and-mortar retail location where filters are stocked on shelves and sold to consumers in the traditional point-of-sale (POS) fashion.

Compromises are thus forced upon consumers, including, for example, the use of filters that are bit small or large in one or both rectangular dimensions, and frustrated consumers even delay or neglect suggested periodic filter replacement. When air driven through an air-handling system bypasses an improperly fitted filter, airborne matter is not optimally trapped at the filter, which can permit the accumulation of matter on HVAC system components and cause or aggravate respiratory problems. When filter replacement schedules are missed, filter blockage by matter / particles accumulated in an old filter can increase system power consumption and wear; it can also harbor microbial growth, which can adversely affect respiratory health. Further, the dimensions as well as the delicate nature of traditional air filters pose some challenges. For example, consumers can find it difficult to handle and transport purchased filters without causing damage to the product. Retailers face additional problems with storing / stocking large and fragile products such as replacement filters; retailers are further forced to make critical calculations regarding stocking a range of filter sizes whereby the shelf-space available for each filter size may be minimized.

Accordingly, opportunities exist for improvements that overcome the above-noted shortcomings of the art.

Prior art patent documents including the following:.

<CIT> and published June <NUM>, <NUM>, is directed to a foldable filter frame including a filter media and a rectangular support frame surrounding and secured to the filter media, having opposed side frame elements having a hingable joint formed near the midpoint that allows the support frame and a dirt-capturing surface of the filter media to fold along lateral line from a planar, extended position to a folded position. The joint includes a fold line in a dirtied-side attaching panel, and a cut formed through a base and a clean-side attaching panel, of the side frame elements, and a means for biasing the joint to the planar, extended position. The biasing means is a strip of elastic member, stapled to an inside surface of the clean-side attaching panel in a relaxed state, across the cut formed through the clean-side attaching panel. The frame can have Velcro-type fasteners in the corners to secure the frame in the folded position.

<CIT> and published June <NUM>, <NUM> is directed to a method for packaging, shipping, displaying and positioning a foldable filter having a hinge into an air filtration unit wherein the foldable filter is pivotable about the hinge between a collapsed position and an expanded position. The method includes the steps of positioning the foldable filter in the collapsed position, inserting the collapsed foldable filter into a package, shipping the collapsed foldable filter within the package to a store, positioning the packaged foldable filter for display at the store, removing the foldable filter from the package, moving the foldable filter to the expanded position and positioning the foldable filter into the air filtration unit. The foldable filter includes first and second frame sections connected by the hinge and pleated filter material that includes at least one pleat edge extending generally parallel to a hinge axis. The hinge is formed at least partially by a portion of the at least one pleat edge.

<CIT> and issued July <NUM>, <NUM>, is directed to a method of making a filter, in which a zigzag filter element of any desired size can be quickly and easily connected to its supports while the filter element is in a compressed form, in which the blank thus formed can then be quickly expanded to operative position, and in which light weight filters of any desired size are produced inexpensively and without separators.

<CIT> and published January <NUM>, <NUM>, is directed to foldable filter assemblies and methods of use thereof. An air filter assembly including a frame having opposed substantially rigid end members and a flexible side member, the end members being connected to the flexible side member, and an air filter media connected to and disposed within the frame such that the frame is adapted to be disposed in a planar use position, and the end members of the frame are adapted to be moved toward each other prior to installation into the planar use position.

WIPO Patent Publication No. <CIT> and published September <NUM>, <NUM>, is directed to an air filter assembly including a filter element having at least one variable dimension, and a frame for engaging and supporting the filter element. The frame may include a plurality of linear segments forming a rectangular configuration, and a plurality of clips for connecting the linear segments together at corners thereof. The linear segments may be L-channel segments, C-channel segments, or may be of other form. Clips may be used for connecting the linear segments together at the corners. The filter element may have a pattern of creases or fold lines to facilitate folding thereof from an expanded configuration to a reduced configuration. A grate may be included for spanning an area bounded by the frame to support the filter element. The grate may have multiple arms and a central hub. An edge treatment may form a seal between the filter element and the frame.

This summary is provided to introduce in a simplified form concepts that are further described in the following detailed descriptions. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it to be construed as limiting the scope of the claimed subject matter.

A collapsible air-filter assembly according to the present invention is as set forth in claim <NUM>. Further features of the collapsible air-filter assembly are set out in the dependent claims.

The previous summary and the following detailed descriptions are to be read in view of the drawings, which illustrate particular exemplary embodiments and features as briefly described below. The summary and detailed descriptions, however, are not limited to only those embodiments and features explicitly illustrated.

Below, the technical solutions in the examples of the present invention are depicted clearly and comprehensively with reference to the figures according to the examples of the present invention. Obviously, the examples depicted here are merely some examples, but not all examples of the present invention. In general, the components in the examples of the present invention depicted and shown in the figures herein can be arranged and designed according to different configurations. Thus, detailed description of the examples of the present invention provided in the figures below are not intended to limit the scope of the present invention as claimed, but merely represent selected examples of the present invention. On the basis of the examples of the present invention, all of other examples that could be obtained by a person skilled in the art without using inventive efforts will fall within the scope of protection of the present invention.

Any dimensions expressed or implied in the drawings and these descriptions are provided for exemplary purposes. Thus, not all embodiments within the scope of the drawings and these descriptions are made according to such exemplary dimensions. The drawings are not made necessarily to scale. Thus, not all embodiments within the scope of the drawings and these descriptions are made according to the apparent scale of the drawings with regard to relative dimensions in the drawings. However, for each drawing, at least one embodiment is made according to the apparent relative scale of the drawing.

Unless described or implied as exclusive alternatives, features throughout the drawings and descriptions should be taken as cumulative, such that features expressly associated with some particular embodiments can be combined with other embodiments.

<FIG> illustrate a collapsible filter assembly <NUM> unfolding in ordered stages from an area-reduced configuration in which its footprint is most reduced ( as illustrated, for example, in <FIG>), to an area-expanded configuration (as illustrated, for example, in <FIG>), in which its footprint is most expanded. To prepare the collapsible filter assembly <NUM> for use, a typical user may remove the filter assembly <NUM> from product packaging <NUM> in the area-reduced configuration of <FIG>, which is preferable for storage and shipping purposes due to the reduced footprint and/or volume. Once removed from the product packaging <NUM>, the collapsible filter assembly <NUM> is expandable to the area-expanded configuration of <FIG>.

The collapsible filter assembly <NUM> further expands volumetrically as shown in <FIG>, which illustrate a sixth configuration of the filter assembly <NUM>, which is preferable for typical use as an air filter. As the collapsible filter assembly <NUM> ultimately has some degree of material flexibility and deformation, particularly when air flow pressures are applied, its operational configuration may be found as somewhat flexed, bulged, or compressed relative to the depictions in the drawings. Nonetheless, the collapsible filter assembly <NUM> can be described as assuming an approximately planar configuration in the fully expanded configuration of <FIG>.

The footprint of the collapsible filter assembly <NUM> is understood as the area, which can be determined, for example, by multiplication of the length L and width W of the filter assembly <NUM>. The footprint of the filter assembly <NUM> in the drawings is rectangular, and can vary in dimensions. Although the length L and width W are only particularly labeled in the drawings in <FIG>, the footprint or area of the filter assembly has an effective lesser area in any of the configurations of <FIG>, for example. The length L and width W are taken in the filter plane, which is generally the plane perpendicular to the direction in which air will flow when the filter assembly is expanded and in use, such that the air flows <NUM> (<FIG>) are directed approximately parallel to the normal axis <NUM> of the filter plane. The normal axis <NUM> is understood as orthogonal to the length L and width W dimensions, and the thickness T of the filter assembly is understood as taken along the normal axis <NUM>. The volume of the collapsible filter assembly <NUM> is understood as approximately the multiplicative product of the length L, width W, and thickness T. In normal use, the air flows <NUM> pass through the thickness T of the filter assembly <FIG> within the fully expanded area of the filter assembly as shown in <FIG>.

In transitioning from a packaged configuration (as shown, for example, in <FIG>) to a configuration as ready for use (as shown, for example, in <FIG>), the collapsible filter assembly is unfolded along engineered fold lines defined along one or more dimensions, such that each fold during the unfolding process successively increases the footprint. Accordingly, during the collapsing process, for example during the manufacturing of the collapsible filter assembly, the collapsing filter assembly is folded along the engineered fold lines such that each fold during the folding process successively decreases the footprint.

The engineered fold lines can be rendered, for example, by thinning or stamping the material, embossing the material, perforating the material, and/or by adding a hinging structure, feature, or material. The quarter-area-reduced configuration of <FIG> can be described as a twice folded configuration having folds in two dimensions relative to the area-expanded configuration of <FIG>. Similarly, the fractionally-reduced-area configuration of <FIG> can be described as a once folded configuration having a fold in one dimension relative to the area-expanded configuration of <FIG>.

The filter assembly <NUM> is designed to be twice folded, with one-fold each in two dimensions. For example, at least one filter assembly is designed to be folded once in one of the two dimensions (i.e., L and W), and folded twice in the other of the two dimensions. For example, an air filter assembly having an expanded footprint of dimensions <NUM> by <NUM> centimetres (<NUM> by <NUM> inches), can be folded three times to have a reduced footprint of approximate dimensions <NUM> by <NUM> centimetres (<NUM> by <NUM> inches). Accordingly, a filter assembly according to these descriptions can be folded once or any number of times.

Transitioning of the collapsed filter assembly for use can also include permitting the collapsible filter assembly to expand in thickness, for example, as shown in transitioning from the configuration of <FIG> to the configuration of <FIG>. The filter assembly is particularly advantageous in that regard, with a rectangular or trapezoidal pleated filter medium element <NUM> and edge treatments <NUM> as further described below with reference to <FIG>. In this particular example the filter assembly <NUM> has approximately rectangular shaped channels <NUM> (see <FIG>) terminating at opposing ends. This design facilitates the top side <NUM> of the filter assembly <NUM> rocking upward as internal channel walls <NUM> unfold upward from a flattened configuration (<FIG>) to standing configuration (<FIG>). The pleated filter medium and edge treatments can be described as having a rectangular-wave shape or a trapezoidal-wave shape as opposed, for example, a triangle wave shape. Thus, the approximately rectangular or trapezoidal pleated filter medium and edge treatments are particularly advantageous for third dimension or thickness (T) expansion / standing (from <FIG>) and reduction / flattening (<FIG>) without damaging the components of the filter assembly.

As shown in <FIG>, filter medium element 110a can include rounded pleat shape channels 112a (instead of rectangular shaped channels <NUM> as shown, for example, in <FIG>). As illustrated in <FIG>, the collapsible filter assembly as disclosed herein can include filter medium element 110a having an original shape profile comprising a rounded pleat shape by way of rounded pleat shape channels 112a. The approximately rounded pleated filter medium and corresponding edge treatments are particularly advantageous for third dimension or thickness (T) expansion /standing and reduction / flattening without damaging the components of the filter assembly.

Conventional air filter pleat shapes are typically triangular, and conventional triangular pleat shapes are stable, strong, and resistant to collapsing; accordingly, when collapsed, convention triangular pleat shapes can suffer from a lack of controlled and repeatable collapse and rebound to their original shape. In contrast to conventional air filter with triangular pleat shape, the present invention can include a rectangular-wave shape, a trapezoidal-wave shape, or a rounded pleat shape wherein the respective pleat shape profile can encourage collapse in a controlled and repeatable manner.

It is noted that there is an additional configuration where the filter only collapses in the thickness "T" dimension, in a similar method as described here, in applications where it is unnecessary or undesirable to additionally reduce the filter in the "W" and "L" dimensions. The filter assembly <NUM> could be removed from product packaging or other compressing constraint in the configuration of <FIG> and then would be expanded to the configuration of <FIG>.

<FIG> is an exploded perspective view of the collapsible filter assembly so as to illustrate exemplary components. As shown, the collapsible filter assembly has a top shell <NUM>, the filter medium element <NUM>, edge treatments <NUM>, and a bottom shell <NUM>. The components of the filter assembly <NUM> are designed to align the engineered folds in the flattened configuration of <FIG> to facilitate folding and unfolding.

The filter assembly <NUM> is referenced herein as a collapsible filter assembly <NUM> according to the rebound tendencies of the materials used and according to the design, which includes, for example, the rectangularly pleated filter medium element <NUM> and edge treatments <NUM>. The filter medium can have pleats that are square, trapezoidal, rounded, and/or saw-toothed. Upon removal of the filter assembly <NUM> from packaging and other restraints, the filter assembly <NUM> naturally expands with regard to foot print and volume, with some manual assistance being expected of a typical user in unfolding from the area-reduced configuration of <FIG>, to the area-expanded configuration of <FIG>, and to the volumetrically expanded configuration of <FIG>. It should be understood that the transitioning from a reduced configuration (<FIG>) freed from packaging to an expanded configuration for use (<FIG>) may depart from the stages and order of steps suggested in considering the drawings as chronologically ordered (<FIG>). Some degree of unflattening (<FIG>) may occur even as the folded filter assembly <NUM> is removed. Each user may treat the filter assembly <NUM> differently and thus each unpackaging and deployment may progress with variations accordingly.

Whereas the figures illustrate a certain dimension of the pleat height, it is to be noted that there is no particular specific aspect ratio between pleat height and pleat width that is required for the invention to operate as intended. Accordingly, the aspect ratio between pleat height and pleat width can be any suitable ratio values. For example, the aspect ratio between pleat height and pleat width can be <NUM>: <NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM> or any other similar ratio values. Inventors have accordingly identified that while the shape of the pleat affects the effectiveness of the collapsible filter assembly to a considerable level, the aspect ratio between pleat height and pleat width does not affect the effectiveness of the collapsible filter assembly as much.

The top shell and bottom shell have matching footprints to form a frame around the filter medium element. Each shell has linear outer edge strips <NUM> along the margins of the filter assembly <NUM> and four sub-frame areas <NUM>; each shell also includes four inner edge strips. Diagonally extending stringers <NUM> span each sub-frame area to stiffen the filter assembly <NUM> and support the filter medium element across the otherwise open areas of the top shell and bottom shell; stringers <NUM> further operate to provide a degree of protection to the filter from mechanical damage.

The top shell and bottom shell are to be constructed of foldable and resilient materials to as to permit reduction and expansion and still provide structural support to the filter assembly <NUM> which may span, with or without additional external support, the interior flow channel of an air duct or other air-handling system interior space in use and under the load of air pressure applied. The top shell and bottom shell may be constructed of polymer, cardboard polyester, polymer and/or plastic. Cardboard or other durable paper or wood-fiber based product may be used.

The edge treatments are constructed of resilient materials having some degree of return force when flattened so as to naturally rebound or unfold to the heightened configuration of <FIG> when released from the flattened configuration of <FIG>. For example, plastic and/or spring steel may be used.

The filter medium element is generally porous and may be layered and may include woven and non-woven materials such as paper, fabrics, piles, felts, mesh, and foams. The filter medium element may include materials that are melt blown, spun bound, carded, expanded, extruded or molded. The filter medium element may include materials having antimicrobial, olfactory, and/or chemical absorbent properties.

The product packaging <NUM> may be a box, bag, envelope or other container and may be padded. The outer dimensions of the product packaging <NUM> may be selected to conform to particular shipping and postage standards for convenience and cost savings or for a particularly desired retail store presence.

Further, the collapsible filter assembly can further include a scrim layer or other similar stiff net-like material comprising a flat top layer and / or a flat bottom layer, with the filter medium element being bounded by the flat top layer and/or the flat bottom layer of the scrim layer, for example. The scrim layer can be configured to have a tensile disposition with bending stiffness whereby the scrim encourages the pleats to rebound to an original / expanded shape profile when in an expanded configuration. Accordingly, the pleated filter medium element can be secured to one or more sheets of the scrim layer. The tensile and bending stiffness of the scrim layer can provide the ability of the pleats to rebound back to their original shape when the collapsible filter assembly is transferred from a collapsed configuration (as shown, for example, in <FIG>) to an expanded configuration (as shown, for example, in <FIG>). For example, a higher stiffness scrim layer can be beneficial for pleat rebound. A stiff scrim layer can also provide additional sturdiness to the filter and reduce deflection of the filter assembly when under load from airflow when in use.

The collapsible filter assembly can further include a frame wrap provided around the edges of the frame of a collapsible filter assembly. The frame wrap around frame edges can encase, surround, or otherwise be attached to the frame of the collapsible filter assembly. The frame wrap around frame edges can be used for functional purposes. For example, frame wrap around frame edges can help seal the ends of the pleated portion of the filter; alternately, or in addition, the frame wrap around frame edges can provide a more compliant surface to help achieve a better seal when the filter assembly is installed in an HVAC register. The frame wrap around frame edges can also help provide a tight-fit to the register to assist installation, were the register holds the filter in place when closing the grating. The frame wrap around frame edges can also prevent the filter assembly from moving up and down when the flow of air is turned on or off. The frame wrap can have a geometry that creates an interference fit and further allows for collapse and expansion for packaging, such as single-bend accordion-style geometry. The frame wrap material can be stiff (for example, the frame wrap material can comprise neoprene) such that elements of the air filter assembly do not need to be secured to each other at the corners. Accordingly, the frame wrap can be configured to seal the ends of the pleated portion of the filter. The frame wrap can also be configured to provide a compliant surface to for a semi-seal to the register, and to further provide a compliant tight-fit to the register to assist installation.

The frame wrap is configured to reduce noise associated with the filter moving when airflow is turned on or turned off. The partial seal created by the frame wrap as well as the disruption to air flow resulting from the frame wrap can operate to reduce and even eliminate the whistling / noise otherwise generated when airflow is turned on or turned off. Through experiments, the inventors have discovered that the reduction in the noise or whistling is accomplished by fabricating the frame wrap from a material that includes sufficient loft such as, for example, felt, flannel, or a similar other material. Through experiments, the inventors have also discovered that this benefit (i.e., the reduction in noise / whistling) is generally not obtained when the filter medium element is made up of a material such as a cotton sheet. Indeed, reduction of noise or whistling by the provision of a frame wrap as discussed above is not limited to collapsible filter assemblies; in other words, reduction of noise or whistling by the provision of a frame wrap as discussed above can also be obtained in conventional / existing non-collapsible filter assemblies that include cardboard frames, for example.

Claim 1:
A collapsible air-filter assembly (<NUM>) comprising:
a filter medium element (<NUM>); and
a frame comprising a top shell (<NUM>) and a bottom shell (<NUM>), wherein the frame is positioned to at least partially surround the filter medium element (<NUM>), wherein the filter medium element (<NUM>) is placed between the top shell (<NUM>) and the bottom shell (<NUM>),
wherein the filter medium element (<NUM>) and the frame each include a plurality of areas separated by at least one engineered fold line;
wherein the frame and the filter medium element (<NUM>) are configured to vary in at least one dimension by folding or unfolding; and
wherein the assembly (<NUM>) is operable to expand from a folded position to an unfolded position along the at least one engineered fold line;
wherein, when the assembly (<NUM>) is in the unfolded position, the filter medium element (<NUM>) is configured to expand volumetrically from a flattened configuration to a standing configuration, and
wherein the filter medium element (<NUM>) is pleated, wherein, in the volumetrically expanded configuration, the filter medium element includes a plurality of channels (<NUM>) extending from end to end, wherein the plurality of channels (<NUM>) includes a rectangular, trapezoidal, or rounded pleat shape.